Bearing seal of the main type refers both end faces of the rolling bearing , the effect of mounting a sealing device . Bearing Sealed With industrial development gradually into the horizon , in recent years that it has been the focus of a technology before the development of the bearing seal bearings are all open bearings .
In the form of bearing seal
Different structure of the bearing seal ring , the sealing effect is also a difference . Seal and the shaft bearing bolt seals a gap between , called non-contact bearing seals , which seal the sealing is better the smaller the gap , but the gap is reduced to allow the shaft will reduce the rotational speed , and vice versa The greater the gap sealing effect is worse , the higher the rotational speed of the shaft allows .
Bearing seal between the shaft seal and the gap does not exist , is known to be contact seals . Bearing seal with contact seal type, seal lip contact with the contact surface of the shaft determines the sealing effect , the greater the contact surface of sealing better, but allows lower speed shaft , otherwise the smaller sealing surface in contact with the sealing effect is more poor, but the shaft allow higher speed .
The role of bearing seal
Maintained a rolling bearing seal the inside and the outside is basically in isolation , bearing the added variety of internal lubricants, grease substances minimal wastage , and lubrication effect has been significantly improved , thus bearing seal can to a large extent to maintain bearing lubrication state.
Another effect of the bearing seal is cut off from the outside world inside the bearing contact with various substances to reduce dust ,strap seals harmful gases and other substances into the bearing cavity chance to reduce impurities inside the bearing because of the formation of a variety of injuries infringement . From one hand, the relative bearing seal can improve bearing life.
pull tight security seals
pull tight security seals
2013年9月26日星期四
Seal pneumatic valve structure and working principle
Lever hoist structure
Lever hoist structure . When the valve is closed, the spindle and the lever with the taper pin fastened around the point o counterclockwise rotation , lever driven off with perforated disc ab, by a compression spring to promote the disc fixed fulcrum on n , with the spindle lever rotates. When the butterfly plate upper b and valve sealing surface to seal all contact . Open the process is reversed . In the opening and closing process , the relative sliding sealing small , reducing the relative wear . In the off state for the axial pressure seal , to change the traditional external compression seal.
By force type actuator rod
By force type actuator rod , the piston in the air under pressure to the right, sliding rod drive arm in the housing , the connecting rod affects rocker clockwise , the output torque. The rod and rocker length (h) the same is equal to the output housing groove cardiac center . Case groove walls subjected to lateral thrust f, p affects rocker rotating component , according to the force analysis shows that:
p = q / cosαα = sin-1 (1-sinβ)
m Twist = phcos (90-α-β) = qhsin (α + β) / cos (α + β)
From the above equation , β angle decreases , α angle increases , m torque value increases. When β = 0 °, α = 90 ° (the valve is closed) , the maximum output torque of drive means ,marker cable ties and in the opening and closing process of the torque is small. This feature is exactly on the curve inclusive of valve operating torque curve , to meet the butterfly valve in the closed or open state seal required torque .
Flat sealing structure
Past pneumatic valve seal pair commonly used spherical sealing , the sealing pressure is radial compression force , the sealing amount of interference can not be adjusted , depending on the sealing performance of the sealing material amount of interference , therefore, the design of the sealing material selected the amount of interference is very important . At work, in particular in zeolite pre-purification process, the switching valve is operated in the range of 10 ~ 200 ℃ , when using the rubber seals , rubber, linear expansion coefficient is large , by the temperature change is large , the amount of interference is difficult to accurately OK. If interference capacity, not only increase the friction , and often appear to "bite edge" and "turn tongue" phenomenon, so seal failure , a small amount of interference appeared leak. Even if the amount of interference reasonable choice , and this valve switching frequently over time due to wear and after the operation will fail . If the use of non-rubber sealing materials, according to information known at present , their elastic deformation is small, the radial seal interference is difficult to control, manufacturing complexity , high cost. While the rubber seal materials, changing the temperature , the temperature of the rubber seal and cause premature aging of the fatigue damage , for large air separation unit is equipped with large-diameter pneumatic butterfly valve, replace the seals will be very difficult.
Since the movement of the valve plate using leveraged institutions , when the valve plate is closed , the valve plate sealing surface contact with the valve seat to become subsequently lever cam mechanism equivalent , if the spindle continues to rotate , then translate the valve plate forward to continue to achieve the balance of forces with working medium pressure, but also to achieve self-sealing , ensure the sealing reliability. When the wear of the sealing surface , the seal also has an automatic wear compensation characteristics , thereby extending the service life.
New sealing pneumatic valve is used flat metal seal structure , the valve as a non- consumable welding of stainless steel alloy, copper alloy seat seal ring with cobalt alloy or stainless steel welding generations , nylon zip ties they are highly resistant to corrosion and abrasion resistance , temperature range, between -40 ~ 300 ℃ in long-term use , so much more life than rubber seal .
Lever hoist structure . When the valve is closed, the spindle and the lever with the taper pin fastened around the point o counterclockwise rotation , lever driven off with perforated disc ab, by a compression spring to promote the disc fixed fulcrum on n , with the spindle lever rotates. When the butterfly plate upper b and valve sealing surface to seal all contact . Open the process is reversed . In the opening and closing process , the relative sliding sealing small , reducing the relative wear . In the off state for the axial pressure seal , to change the traditional external compression seal.
By force type actuator rod
By force type actuator rod , the piston in the air under pressure to the right, sliding rod drive arm in the housing , the connecting rod affects rocker clockwise , the output torque. The rod and rocker length (h) the same is equal to the output housing groove cardiac center . Case groove walls subjected to lateral thrust f, p affects rocker rotating component , according to the force analysis shows that:
p = q / cosαα = sin-1 (1-sinβ)
m Twist = phcos (90-α-β) = qhsin (α + β) / cos (α + β)
From the above equation , β angle decreases , α angle increases , m torque value increases. When β = 0 °, α = 90 ° (the valve is closed) , the maximum output torque of drive means ,marker cable ties and in the opening and closing process of the torque is small. This feature is exactly on the curve inclusive of valve operating torque curve , to meet the butterfly valve in the closed or open state seal required torque .
Flat sealing structure
Past pneumatic valve seal pair commonly used spherical sealing , the sealing pressure is radial compression force , the sealing amount of interference can not be adjusted , depending on the sealing performance of the sealing material amount of interference , therefore, the design of the sealing material selected the amount of interference is very important . At work, in particular in zeolite pre-purification process, the switching valve is operated in the range of 10 ~ 200 ℃ , when using the rubber seals , rubber, linear expansion coefficient is large , by the temperature change is large , the amount of interference is difficult to accurately OK. If interference capacity, not only increase the friction , and often appear to "bite edge" and "turn tongue" phenomenon, so seal failure , a small amount of interference appeared leak. Even if the amount of interference reasonable choice , and this valve switching frequently over time due to wear and after the operation will fail . If the use of non-rubber sealing materials, according to information known at present , their elastic deformation is small, the radial seal interference is difficult to control, manufacturing complexity , high cost. While the rubber seal materials, changing the temperature , the temperature of the rubber seal and cause premature aging of the fatigue damage , for large air separation unit is equipped with large-diameter pneumatic butterfly valve, replace the seals will be very difficult.
Since the movement of the valve plate using leveraged institutions , when the valve plate is closed , the valve plate sealing surface contact with the valve seat to become subsequently lever cam mechanism equivalent , if the spindle continues to rotate , then translate the valve plate forward to continue to achieve the balance of forces with working medium pressure, but also to achieve self-sealing , ensure the sealing reliability. When the wear of the sealing surface , the seal also has an automatic wear compensation characteristics , thereby extending the service life.
New sealing pneumatic valve is used flat metal seal structure , the valve as a non- consumable welding of stainless steel alloy, copper alloy seat seal ring with cobalt alloy or stainless steel welding generations , nylon zip ties they are highly resistant to corrosion and abrasion resistance , temperature range, between -40 ~ 300 ℃ in long-term use , so much more life than rubber seal .
2013年9月25日星期三
Sealants Industry demand situation Reviews
In our country sealant products are widely used in construction, electronic instrumentation and components industries. In recent years , with the rapid development of the market building doors and windows ,Fixed Length plastic seals sealants growing market demand , sealants industry has entered the fast lane , not only usage soared, product variety is also more sophisticated. Sealant is a mainstream product polysulfide rubber and silicone rubber, polysulfide rubber but environmental problems exist , therefore the growing use of low and silicone gel environmental problems do not exist and the cost is greatly reduced , thus becoming the main products sealant is the trend. With polysulfide sealant products market position drop some of the original production of polysulfide sealant companies will converting silicone rubber, silicone rubber market will continue to grow.
China has more than 2,000 enterprises sealant , with the technological level and market demand to expand, more and more enterprises to enter into this industry in the past , the market is increasingly competitive , many companies or invest and build factories or expand production scale, China currently has formed Zhejiang, Guangdong and two silicone sealant production base.
Our sealant will become increasingly fierce market competition , the entry of sealant production costs are lower ,printed cable ties industrial simple , small investment , huge market potential to attract more enterprises to join , so competition will be more intense, disordered competition phenomenon also occurs , which gives the sealant industry development has brought some obstacles .
Sealant product demand continues to grow, enterprises should improve the technological level of the enterprise product positioning in the high-end market , improve product quality and service , and expand the scale of production of silicone rubber , a diversified manufacturing strategy , without prejudice to the relevant industry development, improve their production technology , increase the competitiveness of enterprises so that enterprises in the fierce market competition in an invincible position .
China has more than 2,000 enterprises sealant , with the technological level and market demand to expand, more and more enterprises to enter into this industry in the past , the market is increasingly competitive , many companies or invest and build factories or expand production scale, China currently has formed Zhejiang, Guangdong and two silicone sealant production base.
Our sealant will become increasingly fierce market competition , the entry of sealant production costs are lower ,printed cable ties industrial simple , small investment , huge market potential to attract more enterprises to join , so competition will be more intense, disordered competition phenomenon also occurs , which gives the sealant industry development has brought some obstacles .
Sealant product demand continues to grow, enterprises should improve the technological level of the enterprise product positioning in the high-end market , improve product quality and service , and expand the scale of production of silicone rubber , a diversified manufacturing strategy , without prejudice to the relevant industry development, improve their production technology , increase the competitiveness of enterprises so that enterprises in the fierce market competition in an invincible position .
Hydraulic system factors affecting the performance of seals
Hydraulic oil for hydraulic drive system as the working medium , from the energy transfer , conversion and control role, while also playing the various components within the hydraulic system for lubrication , corrosion , rust and cooling effect.
Hydraulic system plays a seal to prevent leakage of fluid from the joint surfaces , maintaining the pressure , to maintain the role of energy transfer or conversion .
Sealing material used at home and abroad are mostly polymer elastomer , there are a number of special conditions, the use of plastic and various metals. But regardless of what kind of material , should have the following properties:
1 , with some mechanical and physical properties : such as tensile strength , elongation strength , elongation ;
2, there is a certain degree of flexibility, hardness fit and compression set ;
3 , the working media , not prone to swelling , decomposition , hardening ;
4 , wear, there are some anti -tear properties ;
5 , high temperature, low temperature aging .
However , there is no numbered seals sealing materials include all of the above properties , the need to work environment, such as temperature , pressure, media and sport mode to select the suitable sealing material , and through the development of materials with recipe to meet certain requirements . Or the use of composite materials or a combination of two or more structures in the form of play to their strengths, to achieve more comprehensive results.
Seal formation : dynamic seal is divided into non-contact seals and contact seals . Non-contact seal mainly a variety of mechanical seals , such as: graphite packing ring , floating ring seals ; rubber composite seals and rubber seals belong portfolio contact seals , relying on filling in a sealed chamber in the pre- compression force , leakage channel blocking sealing effect is obtained . Seals used in hydraulic systems are mostly static seal ( seal ) , reciprocating seals ( piston, piston rod plastic seals seal ) and rotating seal .
Factors affecting the sealing effect : seal structure selection and film formation , pressure, temperature , material compatibility , dynamic sealing contact with the working surface of the material, hardness , geometry, surface finish .
Hydraulic system plays a seal to prevent leakage of fluid from the joint surfaces , maintaining the pressure , to maintain the role of energy transfer or conversion .
Sealing material used at home and abroad are mostly polymer elastomer , there are a number of special conditions, the use of plastic and various metals. But regardless of what kind of material , should have the following properties:
1 , with some mechanical and physical properties : such as tensile strength , elongation strength , elongation ;
2, there is a certain degree of flexibility, hardness fit and compression set ;
3 , the working media , not prone to swelling , decomposition , hardening ;
4 , wear, there are some anti -tear properties ;
5 , high temperature, low temperature aging .
However , there is no numbered seals sealing materials include all of the above properties , the need to work environment, such as temperature , pressure, media and sport mode to select the suitable sealing material , and through the development of materials with recipe to meet certain requirements . Or the use of composite materials or a combination of two or more structures in the form of play to their strengths, to achieve more comprehensive results.
Seal formation : dynamic seal is divided into non-contact seals and contact seals . Non-contact seal mainly a variety of mechanical seals , such as: graphite packing ring , floating ring seals ; rubber composite seals and rubber seals belong portfolio contact seals , relying on filling in a sealed chamber in the pre- compression force , leakage channel blocking sealing effect is obtained . Seals used in hydraulic systems are mostly static seal ( seal ) , reciprocating seals ( piston, piston rod plastic seals seal ) and rotating seal .
Factors affecting the sealing effect : seal structure selection and film formation , pressure, temperature , material compatibility , dynamic sealing contact with the working surface of the material, hardness , geometry, surface finish .
2013年9月24日星期二
Valve leakage sealing performance factors
Assessment of the valve is the valve sealing performance merits of the main indicators of quality . Valve sealing performance factors that may affect whether the valve leakage and leakage size. Valve sealing performance mainly include two aspects, namely, leakage and leakage . Endoleak refers to the closure member between the valve seat and sealing of the media reach , assessment criteria within the country there are two missing . One is the State Technical Supervision Bureau released in December 1992 , June 1, 1993 began the implementation of a national standard GB/T13927-1992 " universal valve pressure test ." This standard is used with reference to the international standard ISO5208-1982 " Industrial valve pressure test " developed ; another was issued by the Ministry of Machinery Industry JB/T9092-1999 " valve testing and inspection ," This standard is referenced API598-1986 "Valve inspection and test " developed .
GB/T13927-1992 for general industrial valves inspection ; JB/T9092-1999 industrial valves for the oil inspection . Leakage refers to the parts of the stem packing leak , the leak in the flange gasket and valve parts casting defects caused due to leakage, leakage is simply not allowed. If the media is not allowed into the atmosphere , then the leakage of seal leakage than the inner seal more important. Therefore, the valve sealing performance should lead to the manufacturer 's attention.
Factors affecting the performance of the main valve seal are: ① sealing surface quality ; ② sealing surface width ; ③ valve before and after the valve pressure difference ; ④ sealing surface material and its processing status ; ⑤ media properties ; ⑥ surface hydrophilicity ; ⑦ seal film presence ; ⑧ closed parts of rigidity and structural characteristics .
( 1 ) the width of the sealing surface of the valve sealing performance of the sealing surface width determines the length of the pores . When the width is increased, fluid movement along the pores stroke lengthened to increase the resistance movement . Can be reduced to increase the width of the sealing surface pressure in the valve erosive wear . Increase the width of the sealing surface , it will cause leakage increased in proportion to the stroke length , and thus be able to proportionately reduce leakage. But the sealing surface width increases , in the same sealing force , wire seal the sealing pressure than decreases, but also make the possibility of leakage increases. Therefore, the increase can not be unlimited sealing surface width.
( 2 ) The quality of the sealing surface of the valve sealing performance of the sealing surface of the valve seat and the closure member is in contact with each other to shut down part. When the sealing surface pressure at 40MPa or less, the quality of the sealing surface of the valve sealing performance play a decisive role . This is because : When the sealing surface pressure is small, low surface roughness , the leakage is increasing rapidly . When the sealing surface pressure is large, the surface roughness on the leakage has been significantly reduced .
⑶ valve before and after the valve differential pressure on the valve sealing performance is analyzed theoretically , valves before and after the valve pressure difference is proportional to both the amount of leakage . But tests proved : in other conditions are the same , the leakage volume growth is increasing pressure differential over .
Leakage between the pressure difference can be approximated by the following formula :
G = M (N △ P2 + S △ P) where : M, N, S - constant coefficients, which depend on the material , the processing quality of the sealing surface , security seals sealing surface pressure and other conditions ;
△ P - pressure differential.
GB/T13927-1992 for general industrial valves inspection ; JB/T9092-1999 industrial valves for the oil inspection . Leakage refers to the parts of the stem packing leak , the leak in the flange gasket and valve parts casting defects caused due to leakage, leakage is simply not allowed. If the media is not allowed into the atmosphere , then the leakage of seal leakage than the inner seal more important. Therefore, the valve sealing performance should lead to the manufacturer 's attention.
Factors affecting the performance of the main valve seal are: ① sealing surface quality ; ② sealing surface width ; ③ valve before and after the valve pressure difference ; ④ sealing surface material and its processing status ; ⑤ media properties ; ⑥ surface hydrophilicity ; ⑦ seal film presence ; ⑧ closed parts of rigidity and structural characteristics .
( 1 ) the width of the sealing surface of the valve sealing performance of the sealing surface width determines the length of the pores . When the width is increased, fluid movement along the pores stroke lengthened to increase the resistance movement . Can be reduced to increase the width of the sealing surface pressure in the valve erosive wear . Increase the width of the sealing surface , it will cause leakage increased in proportion to the stroke length , and thus be able to proportionately reduce leakage. But the sealing surface width increases , in the same sealing force , wire seal the sealing pressure than decreases, but also make the possibility of leakage increases. Therefore, the increase can not be unlimited sealing surface width.
( 2 ) The quality of the sealing surface of the valve sealing performance of the sealing surface of the valve seat and the closure member is in contact with each other to shut down part. When the sealing surface pressure at 40MPa or less, the quality of the sealing surface of the valve sealing performance play a decisive role . This is because : When the sealing surface pressure is small, low surface roughness , the leakage is increasing rapidly . When the sealing surface pressure is large, the surface roughness on the leakage has been significantly reduced .
⑶ valve before and after the valve differential pressure on the valve sealing performance is analyzed theoretically , valves before and after the valve pressure difference is proportional to both the amount of leakage . But tests proved : in other conditions are the same , the leakage volume growth is increasing pressure differential over .
Leakage between the pressure difference can be approximated by the following formula :
G = M (N △ P2 + S △ P) where : M, N, S - constant coefficients, which depend on the material , the processing quality of the sealing surface , security seals sealing surface pressure and other conditions ;
△ P - pressure differential.
Model of the mechanical seal
In order to adapt to different working conditions , there are many different mechanical seal of the type :
1, according to the logarithm of the seal faces , into a single face , double face and other mechanical seal.
Single face - the sealing device in only one pair of seal faces . It is simple in structure , is commonly used mechanical seal type .
Double face - the sealing device has two end faces of the seal . Its complex structure, suitable for highly corrosive , flammable , toxic and harmful media and vacuum applications.
2, according to the role of the sealed fluid pressure in the sealed end face is unloading or unloading can be divided into balanced and unbalanced mechanical seal .
Balanced - sealed fluid pressure acting on the seal end face of the part or all of unloading unloading .
Unbalanced - the sealed fluid acting on the end surface of the sealing pressure is not unloading .
Balanced suitable for medium and high-pressure conditions of mechanical seals ; unbalanced voltage conditions applicable to the mechanical seal.
3, according to the spring is placed within a security stickers sealed fluid is divided into spring and spring built-in external mechanical seal.
Built-in spring - spring is placed within a sealed fluid .
External spring - spring placed outside the sealed fluid .
Spring built-in seal face stress state is good, small amount of leakage , cooling and lubrication is good. So, in addition to corrosive media , shall as far as possible using the built -in structure .
4, according to the number of springs compensation structure , divided into single and multi- spring type spring type mechanical seal .
Single spring - in only one spring compensation mechanism . It is used for lighting loads , shaft diameter smaller occasions .
Multi-spring - in the compensation mechanism has a plurality of springs . For the larger shaft diameter . Sealing end face spring force distribution is more uniform, but the spring wire diameter is small, a greater impact of corrosion on the spring .
5, according to whether the compensation mechanism rotates with the shaft is divided into rotary and stationary mechanical seal.
Rotary - compensating ring rotates with the shaft .
Static - compensation ring does not rotate with the shaft .
General mechanical rotary tamper evident label seal is often used , because the compensation mechanism and the shaft is simple in structure , small radial dimension . However, in high-speed conditions, compensation and other rotating parts ring centrifugal force generated greater impact , balancing high requirements , the use of static type is more appropriate.
1, according to the logarithm of the seal faces , into a single face , double face and other mechanical seal.
Single face - the sealing device in only one pair of seal faces . It is simple in structure , is commonly used mechanical seal type .
Double face - the sealing device has two end faces of the seal . Its complex structure, suitable for highly corrosive , flammable , toxic and harmful media and vacuum applications.
2, according to the role of the sealed fluid pressure in the sealed end face is unloading or unloading can be divided into balanced and unbalanced mechanical seal .
Balanced - sealed fluid pressure acting on the seal end face of the part or all of unloading unloading .
Unbalanced - the sealed fluid acting on the end surface of the sealing pressure is not unloading .
Balanced suitable for medium and high-pressure conditions of mechanical seals ; unbalanced voltage conditions applicable to the mechanical seal.
3, according to the spring is placed within a security stickers sealed fluid is divided into spring and spring built-in external mechanical seal.
Built-in spring - spring is placed within a sealed fluid .
External spring - spring placed outside the sealed fluid .
Spring built-in seal face stress state is good, small amount of leakage , cooling and lubrication is good. So, in addition to corrosive media , shall as far as possible using the built -in structure .
4, according to the number of springs compensation structure , divided into single and multi- spring type spring type mechanical seal .
Single spring - in only one spring compensation mechanism . It is used for lighting loads , shaft diameter smaller occasions .
Multi-spring - in the compensation mechanism has a plurality of springs . For the larger shaft diameter . Sealing end face spring force distribution is more uniform, but the spring wire diameter is small, a greater impact of corrosion on the spring .
5, according to whether the compensation mechanism rotates with the shaft is divided into rotary and stationary mechanical seal.
Rotary - compensating ring rotates with the shaft .
Static - compensation ring does not rotate with the shaft .
General mechanical rotary tamper evident label seal is often used , because the compensation mechanism and the shaft is simple in structure , small radial dimension . However, in high-speed conditions, compensation and other rotating parts ring centrifugal force generated greater impact , balancing high requirements , the use of static type is more appropriate.
2013年9月21日星期六
Introduction silicone sealant for construction and use of pitfalls and errors
Construction silicone sealant as today's most widely used in various building exterior decoration waterproof sealing material has been accepted by all . But with silicone sealant for construction developed rapidly, such as colloidal stiff , brittle powder, oil leakage pollution, glue seam cracking, pieces of insulating glass unit failure , deterioration and other structural bonding affect the building features and security problems have gradually show. Partly due to vicious market competition has led many manufacturers in the construction silicone sealant to increase the production of plasticizers cause , but there are also a large part because consumers do not understand the product performance or improper construction of the operator directly affect the overall performance of silicone rubber products .
To introduce the following silicone sealants used in construction as well as the basics of the process in the purchase and use of a number of errors and improper methods .
1 Introduction silicone sealant
A, the characteristics of silicone sealant
Silicone sealant refers to a linear polysiloxane as the main raw materials to produce sealants, also called silicone sealant .
Silicone sealant polymer main chain mainly composed of silicon -oxygen -silicon bond composition , coloured cable ties cross-linking agent during the curing reaction of the base polymer to form a network of Si-Q-Si backbone structure . And other polymers , and organic sealant (such as: polyurethane sealant, acrylic sealant, polysulfide sealant , etc. ) compared to the most significant feature is the excellent high temperature properties and weather resistance properties.
Above table shows , Si-0-Si bond can be very high, not only much larger than the other polymers bond energy ( other chemical bond are below 300nrn UV bond energy ) , and Si 101 Si bond energy is higher than UV bond energy , which is used in construction sealants under UV irradiation still maintain good performance, but other organic polymer material is easily root cause of aging . Therefore, construction silicone sealant has very good weather resistance.
B, m with silicone sealant construction Classification
Silicone sealant construction is mostly used at room temperature vulcanizing (RTV) type condensation cure system, security seals that does not require heat curing , can be cured at room temperature , and the curing process will release some small molecules .
To introduce the following silicone sealants used in construction as well as the basics of the process in the purchase and use of a number of errors and improper methods .
1 Introduction silicone sealant
A, the characteristics of silicone sealant
Silicone sealant refers to a linear polysiloxane as the main raw materials to produce sealants, also called silicone sealant .
Silicone sealant polymer main chain mainly composed of silicon -oxygen -silicon bond composition , coloured cable ties cross-linking agent during the curing reaction of the base polymer to form a network of Si-Q-Si backbone structure . And other polymers , and organic sealant (such as: polyurethane sealant, acrylic sealant, polysulfide sealant , etc. ) compared to the most significant feature is the excellent high temperature properties and weather resistance properties.
Above table shows , Si-0-Si bond can be very high, not only much larger than the other polymers bond energy ( other chemical bond are below 300nrn UV bond energy ) , and Si 101 Si bond energy is higher than UV bond energy , which is used in construction sealants under UV irradiation still maintain good performance, but other organic polymer material is easily root cause of aging . Therefore, construction silicone sealant has very good weather resistance.
B, m with silicone sealant construction Classification
Silicone sealant construction is mostly used at room temperature vulcanizing (RTV) type condensation cure system, security seals that does not require heat curing , can be cured at room temperature , and the curing process will release some small molecules .
New building materials polyurethane sealant application status
Sealant is a scene filling them , room temperature curing adhesive seams elastic sealing material , is nearly 10 years the rapid development of a new type of building materials, their industrialization encouraged and supported by the State . With modern urban architecture , architectural design and construction technology advances, decoration quality continues to improve, sealant construction and home decoration rapid growth in consumption , a strong impetus to the sealant industry. Especially in the 20th century , 90 years after sealant adhesive wall structure fitted with a structural material , the state "July" , "August " and " Nine Five" research program, have included insulating glass sealant , security ties construction high and low modulus silicone sealant, sealant production equipment and product standardization projects, the state and enterprises gradually increase investment in this area , to form a polyurethane , polysulfide , acrylic , silicone sealants and other emerging industries as the mainstay . At present, China sealant production reached 60,000 tons .
Polyurethane sealant used in construction of the current low price silicone sealant for construction, erosion has exposed concrete , oil leakage pollution, easy tear, you can not paint and other defects, particularly in the precast concrete panels and stone wall joints , airport, bridge concrete and glass fiber reinforced concrete construction and other structural joints watertight seal problem has become more prominent. Polyurethane sealant with tearing, abrasion resistance, puncture , the substrate does not pollute , acid and alkali resistance, organic solvents, paint , stone and concrete for non-corrosion properties , which stand out in the application . Polyurethane sealant has good prospects for development, with the gradual expansion of the construction market , the demand will gradually increase . In addition, polyurethane has a lively isocyanate groups , better cost performance can be modified development of new products. As long as the increased production of polyurethane sealant renovation investment, increase the development, promotion , and constantly develop marketable functional products , China's construction polyurethane sealant production will be substantial growth in recent years .
At present , China's construction sealant products have been adopted ISO11600 " structural sealant · · Classification and requirements " standard, raised 11 levels and the corresponding technical specifications ,tamper seal requirements and test methods , research and development should comply with the relevant sealant modulus and displacement capacity regulations. Polyurethane sealant must enhance their ability to innovate, develop new China already has a silicone sealant , polyurethane, polysulfide , acrylic sealant and other products in the future should be based primarily large enterprises or enterprise groups enhance product innovation, based on the existing stable quality, expand production scale, strengthen and new modified polymer sealant developed highly functional , improving product technology content and added value , promote the construction of new technological developments .
Polyurethane sealant used in construction of the current low price silicone sealant for construction, erosion has exposed concrete , oil leakage pollution, easy tear, you can not paint and other defects, particularly in the precast concrete panels and stone wall joints , airport, bridge concrete and glass fiber reinforced concrete construction and other structural joints watertight seal problem has become more prominent. Polyurethane sealant with tearing, abrasion resistance, puncture , the substrate does not pollute , acid and alkali resistance, organic solvents, paint , stone and concrete for non-corrosion properties , which stand out in the application . Polyurethane sealant has good prospects for development, with the gradual expansion of the construction market , the demand will gradually increase . In addition, polyurethane has a lively isocyanate groups , better cost performance can be modified development of new products. As long as the increased production of polyurethane sealant renovation investment, increase the development, promotion , and constantly develop marketable functional products , China's construction polyurethane sealant production will be substantial growth in recent years .
At present , China's construction sealant products have been adopted ISO11600 " structural sealant · · Classification and requirements " standard, raised 11 levels and the corresponding technical specifications ,tamper seal requirements and test methods , research and development should comply with the relevant sealant modulus and displacement capacity regulations. Polyurethane sealant must enhance their ability to innovate, develop new China already has a silicone sealant , polyurethane, polysulfide , acrylic sealant and other products in the future should be based primarily large enterprises or enterprise groups enhance product innovation, based on the existing stable quality, expand production scale, strengthen and new modified polymer sealant developed highly functional , improving product technology content and added value , promote the construction of new technological developments .
2013年9月17日星期二
Centrifugal method for each component overhaul
First, the packing seal repair methods
1, cleaning centrifugal pump stuffing box and check whether the shaft surface scratches, burrs, etc. . Stuffing box should be cleaned shaft surface should be smooth .
2, check shaft runout , unbalance of the rotor should be beating within the allowable range ,indicative seal in order to avoid excessive vibration , the filler negative.
3 , the packing box and shaft sealant coated or coated with a lubricant adapted to the media .
4, rolls packing filler with a time of first take root stick with the journal of the same size , the packing wound on it , and then cut with a knife , blade best was 45 ° slope.
5 , packing to loading by the root , not one filled with a few . Method is to take a filler coated with a lubricant , filler interface, each hand holding one end opened in the axial direction , so that a spiral , and then coat the incision into the journal . Shall not be opened along the radial direction in order to avoid missing the interface .
6 , take a box of the same size with the filler material or be lower than the hardness of the metal shaft bushings, push the stuffing box deep , with gland put some pressure on the sleeve , so that the filler be pre-compressed . Precompression of 5% to 10%, up to 20%. Then the shaft is rotated one week , remove the sleeve .
7 , in the same way , filling the second , third, . Note that when the filler number of 4 to 8 , the filling should be the interface to each other by 90 °; two fillers shifted 180 °; 3 ~ 6根shifted 120 °, to prevent leakage through the interface .
8 , the last one filler loading is complete, the application gland pressed, but pressing force is not too large .metal seal While rotating shaft by hand to make assembly clamping force tends parabolic profile . Then relax a little gland .
9 , for running test , if not sealed , then pressed a number of filler ; if fever is too large , it would relax some of the . So transferred was only little droplets when leakage and heat up ( only fill part of the temperature than the ambient temperature 30 ~ 40 ℃), before they can be put into use.
1, cleaning centrifugal pump stuffing box and check whether the shaft surface scratches, burrs, etc. . Stuffing box should be cleaned shaft surface should be smooth .
2, check shaft runout , unbalance of the rotor should be beating within the allowable range ,indicative seal in order to avoid excessive vibration , the filler negative.
3 , the packing box and shaft sealant coated or coated with a lubricant adapted to the media .
4, rolls packing filler with a time of first take root stick with the journal of the same size , the packing wound on it , and then cut with a knife , blade best was 45 ° slope.
5 , packing to loading by the root , not one filled with a few . Method is to take a filler coated with a lubricant , filler interface, each hand holding one end opened in the axial direction , so that a spiral , and then coat the incision into the journal . Shall not be opened along the radial direction in order to avoid missing the interface .
6 , take a box of the same size with the filler material or be lower than the hardness of the metal shaft bushings, push the stuffing box deep , with gland put some pressure on the sleeve , so that the filler be pre-compressed . Precompression of 5% to 10%, up to 20%. Then the shaft is rotated one week , remove the sleeve .
7 , in the same way , filling the second , third, . Note that when the filler number of 4 to 8 , the filling should be the interface to each other by 90 °; two fillers shifted 180 °; 3 ~ 6根shifted 120 °, to prevent leakage through the interface .
8 , the last one filler loading is complete, the application gland pressed, but pressing force is not too large .metal seal While rotating shaft by hand to make assembly clamping force tends parabolic profile . Then relax a little gland .
9 , for running test , if not sealed , then pressed a number of filler ; if fever is too large , it would relax some of the . So transferred was only little droplets when leakage and heat up ( only fill part of the temperature than the ambient temperature 30 ~ 40 ℃), before they can be put into use.
Under high pressure mechanical seal
Under high pressure mechanical seal
Mechanical seals operating pressure exceeds 4 ~ 5MPa that belong to high-pressure sealing range . In the high-pressure conditions, due to the seal faces than the pressure value is too large , causing the face , fever, thereby undermining the film formation , resulting in abnormal wear . High friction can also make deformation and rupture. High pressure seal generally a balanced structure, so that the end than the pressure in an appropriate range . But taking into account the reliability of sealing balance coefficient increases can not be unlimited , and thus in some cases despite using a balanced structure, but may still be greater than the pressure face . Balanced structure alone is difficult to meet the requirements , this situation can be multi- end mechanical seal or controlled membrane mechanical seal.
Second, the high temperature mechanical seals
Generally, the medium temperature exceeds 120 ℃ is considered to be heat-sealed . At this time the main problems the mechanical seal are:
( 1) Since the friction face temperature, resulting vaporized film between the seal faces , the friction coefficient increases, increased wear , temperature increase, the sealing ring thermal deformation or thermal cracking and failure ;
( 2 ) The secondary seal mechanical luggage seals materials are generally rubber or PTFE , because for a long time in a hot environment , easy to aging and decomposition , resulting in seal failure ;
( 3 ) high temperature mechanical seal is easy to produce an elastic member and creep fatigue , failure of the seal ;
( 4 ) high-temperature corrosion of metallic materials will intensify and shorten the life of the mechanical seal .
To ensure mechanical seals in high temperature environment to work properly, you can take the following measures.
1 to increase the cooling mechanical seal flushing device .
2 Select the temperature of the material , depending on the operating temperature used different materials. Nitrile rubber upper temperature limit is 80 ℃, silicone rubber and fluorine rubber of 200 ℃, PTFE as 250 ℃.
In addition, the mechanical seal multi -metallic friction material impregnated with graphite , so they will have different operating temperature based on selection of different types of impregnated graphite . General Baptist babbitt graphite suitable temperature range is less than 150 ℃, resin-impregnated graphite temperature range of 170 ~ 200 ℃, leaching of copper, aluminum, lead and graphite at less than 400 ℃ working conditions. Ring components should be used wherever possible expansion coefficient similar material to prevent high temperatures ring and ring seat loose connection.
3 Select the metal bellows mechanical seal. Metal bellows seal used in recent years in many high temperature sealing , and achieved good results. In this kind of mechanical seal , the metal bellows mechanical security seals replaces the ordinary in spring , eliminating the need for secondary seal ring , ring compensation is not required to overcome the friction and wear of the shaft , so use at high temperatures , are generally able to achieve good results.
Mechanical seals operating pressure exceeds 4 ~ 5MPa that belong to high-pressure sealing range . In the high-pressure conditions, due to the seal faces than the pressure value is too large , causing the face , fever, thereby undermining the film formation , resulting in abnormal wear . High friction can also make deformation and rupture. High pressure seal generally a balanced structure, so that the end than the pressure in an appropriate range . But taking into account the reliability of sealing balance coefficient increases can not be unlimited , and thus in some cases despite using a balanced structure, but may still be greater than the pressure face . Balanced structure alone is difficult to meet the requirements , this situation can be multi- end mechanical seal or controlled membrane mechanical seal.
Second, the high temperature mechanical seals
Generally, the medium temperature exceeds 120 ℃ is considered to be heat-sealed . At this time the main problems the mechanical seal are:
( 1) Since the friction face temperature, resulting vaporized film between the seal faces , the friction coefficient increases, increased wear , temperature increase, the sealing ring thermal deformation or thermal cracking and failure ;
( 2 ) The secondary seal mechanical luggage seals materials are generally rubber or PTFE , because for a long time in a hot environment , easy to aging and decomposition , resulting in seal failure ;
( 3 ) high temperature mechanical seal is easy to produce an elastic member and creep fatigue , failure of the seal ;
( 4 ) high-temperature corrosion of metallic materials will intensify and shorten the life of the mechanical seal .
To ensure mechanical seals in high temperature environment to work properly, you can take the following measures.
1 to increase the cooling mechanical seal flushing device .
2 Select the temperature of the material , depending on the operating temperature used different materials. Nitrile rubber upper temperature limit is 80 ℃, silicone rubber and fluorine rubber of 200 ℃, PTFE as 250 ℃.
In addition, the mechanical seal multi -metallic friction material impregnated with graphite , so they will have different operating temperature based on selection of different types of impregnated graphite . General Baptist babbitt graphite suitable temperature range is less than 150 ℃, resin-impregnated graphite temperature range of 170 ~ 200 ℃, leaching of copper, aluminum, lead and graphite at less than 400 ℃ working conditions. Ring components should be used wherever possible expansion coefficient similar material to prevent high temperatures ring and ring seat loose connection.
3 Select the metal bellows mechanical seal. Metal bellows seal used in recent years in many high temperature sealing , and achieved good results. In this kind of mechanical seal , the metal bellows mechanical security seals replaces the ordinary in spring , eliminating the need for secondary seal ring , ring compensation is not required to overcome the friction and wear of the shaft , so use at high temperatures , are generally able to achieve good results.
2013年9月13日星期五
Reaction kettle mechanical seal structure and working principle
Reactor mechanical seal comprises a spring loading device , ring, stationary ring and auxiliary seals and other four parts.
Reactor mechanical seal generally have four face :
A reactor with static ring seal between the stationary ring seat is static sealing the reactor , generally produced with flexible secondary seal to prevent leakage.
2 reactor stationary ring seal between the seat and the device is static sealing the reactor , can be produced with ordinary gasket seal.
3 reactor ring and shaft (sleeve ) between the metal seal , this is a relatively stationary seal , usually 0 -ring to seal .
These three are all static sealing , can produce measures to prevent leakage.
4 reactor stationary ring and the relative rotation between the sealing ring , belonging to dynamic seal, is to rely on a spring loading device and media pressure on the relative rotation . Static ring and ring contact surface between the ( end ) to generate a suitable clamping force ,bolt seal so that the two smooth, flat end face snug fit between the end face of the fluid while maintaining a very thin layer to achieve the purpose of sealing .
Reactor mechanical seal generally have four face :
A reactor with static ring seal between the stationary ring seat is static sealing the reactor , generally produced with flexible secondary seal to prevent leakage.
2 reactor stationary ring seal between the seat and the device is static sealing the reactor , can be produced with ordinary gasket seal.
3 reactor ring and shaft (sleeve ) between the metal seal , this is a relatively stationary seal , usually 0 -ring to seal .
These three are all static sealing , can produce measures to prevent leakage.
4 reactor stationary ring and the relative rotation between the sealing ring , belonging to dynamic seal, is to rely on a spring loading device and media pressure on the relative rotation . Static ring and ring contact surface between the ( end ) to generate a suitable clamping force ,bolt seal so that the two smooth, flat end face snug fit between the end face of the fluid while maintaining a very thin layer to achieve the purpose of sealing .
Square sealed cans kept most suitable seasoning
Slimline sealed bottle
A class can be sealed liquid foods, like honey , edible oil and so on. In addition to decorating the room can be used as exhibit .
Square Canister
Seasonings used to store the better. Chili, pepper , aniseed , and so will a glance . Lid groove design can safely be placed overlapping .
White Porcelain Canister
Generous appearance , classical tastes strong ,id cable ties each tank with a wooden spoon , Sheng things very convenient. Storing sugar, salt is the best choice.
Cube Canister
There are many models of choice, according to your needs . Max model can store 10 pounds of rice . You can buy a few to hold innocent grains , placed in a row, both beautiful and practical.
Cute little jar
Can be used to hold children like to eat candy , colorful it is not only beautiful but also increase appetite .
Glass printing Canister
Work more elegant , usually on more prominent place , coloured cable ties such as coffee table top. So, used to hold tea very appropriate , especially the various tea , that seductive beauty.
Color fancy sealed cans
Many young people have choice. On the decoration of the room is decorated personality played a significant role. In fact, anything can be used to hold , to see which you like to put them up . Overhaul of the mechanical seal
A class can be sealed liquid foods, like honey , edible oil and so on. In addition to decorating the room can be used as exhibit .
Square Canister
Seasonings used to store the better. Chili, pepper , aniseed , and so will a glance . Lid groove design can safely be placed overlapping .
White Porcelain Canister
Generous appearance , classical tastes strong ,id cable ties each tank with a wooden spoon , Sheng things very convenient. Storing sugar, salt is the best choice.
Cube Canister
There are many models of choice, according to your needs . Max model can store 10 pounds of rice . You can buy a few to hold innocent grains , placed in a row, both beautiful and practical.
Cute little jar
Can be used to hold children like to eat candy , colorful it is not only beautiful but also increase appetite .
Glass printing Canister
Work more elegant , usually on more prominent place , coloured cable ties such as coffee table top. So, used to hold tea very appropriate , especially the various tea , that seductive beauty.
Color fancy sealed cans
Many young people have choice. On the decoration of the room is decorated personality played a significant role. In fact, anything can be used to hold , to see which you like to put them up . Overhaul of the mechanical seal
Pump Failure introduce dynamic seal
Core Tip: pump seals are soft packing seals , oil seals , labyrinth seals , spiral seals, dynamic seals and mechanical seals.
Prevent the working medium from leaking out of the pump or to prevent impurities or outside air intrusion into the pump means or measures known internal seal medium to be sealed is generally liquid, gas or dust .
Causing leakage for two main reasons : First, there is a gap sealing surface . Second, the pressure difference on both sides of the sealing parts , to eliminate or reduce any of the factors that can prevent or reduce leakage , to achieve the purpose of sealing . Pressure pump design and the use of pressure is an objective can not be reduced , so that the pump is sealed to the solution to eliminate or reduce the gap between the seal faces . Such a gap includes a gap between the sealing surface and the sealing means within the gap Bunsen .
Mechanical seals
Modern shaft seal mechanical seal is the main method , though use of it is not easy to achieve completely leak , but the reach of tiny , it is perfectly acceptable amount of leakage is entirely possible. However, the operation of the pump , but often embarrassing situation, then the mechanical seal failure because what is it ?
1, the mechanical seal material selection inappropriate. Mechanical seal material and the transmission medium does not match. In operation, the sealing element will soon be corrosion, dissolution or wear , thus losing the sealing capability. Therefore, according to the nature of the transmission medium and the choice of the mechanical seal material is to ensure its sealing function and the normal life of the prerequisites.
2 , the mechanical seal flush condition does not meet the design requirements. In conveying easy to crystallize or fine particles of the medium , there must be a certain pressure and a certain flow of fluid to wash , or their crystals or particles will accelerate the sealing wear and affect the sealing of worn automatic compensation leak. Therefore, according to the nature of the transmission medium not only to configure the appropriate flushing lines , but also to install a monitoring and regulation instruments and devices to ensure that fluid pressure and flow to meet the design requirements, in order to maintain the normal operation of the mechanical seal , which is often overlooked by users .
3 , each of the mechanical seal can withstand the pressure is limited , due to the seal chamber pressure measurement are not allowed, resulting in the seal chamber pressure exceeds the mechanical seal can withstand the pressure of the leak , is a common sealing one reason for failure .
4 , the mechanical seal operating temperature can not exceed the specified value. In the design of a cooling circuit , often due to insufficient flow of the cooling medium leaving the cooling effect is reduced ; without the cooling circuit design, the numbered seals cavity often as harbored in the air and cause mechanical seal dry friction condition. In both cases, the movement of the mechanical seal sealing temperature is too high and accelerated wear, resulting in seal failure.
5 , the use of a single spring mechanical seals ignored when spring pump rotor rotation direction and the direction of rotation correct combination also occurs . Or design without instructions or assembly negligence , failed to do so because of the rotation of the rotor mechanical seal leaving but on the contrary increase the spring force , resulting in the ring and stationary ring friction pairs formed insufficient pressure leak .
6 , bearing severe wear or damage , so that axial movement of the shaft produce severe , but also one of the reasons mechanical seal leakage . With the scientific and technological development, new seals and sealing materials , emerging forms , which is bound to the pump seal technology have a direct impact and promoted. Long life, zero leakage pump products in a growing number of occasions to get promotion and application.
Oil seals
Self-tight seal is a lip fixed length plastic strap seal , its simple structure , small size , low cost , easy maintenance, resistance torque is small, both to prevent media leaks , but also to prevent external intrusion of dust and other harmful substances , but also to wear have a certain ability to compensate , but the impatience high pressure, it is generally used in low pressure applications. Seal should be installed in the manufacturing precision of h8 ~ h9, the surface roughness of 1.6 ~ 0.8μm and after surface hardening treatment of the shaft . Sealing medium should not contain solid particles and impurities , which will cause rapid wear of the shaft seal and leaving the seal failure.
Prevent the working medium from leaking out of the pump or to prevent impurities or outside air intrusion into the pump means or measures known internal seal medium to be sealed is generally liquid, gas or dust .
Causing leakage for two main reasons : First, there is a gap sealing surface . Second, the pressure difference on both sides of the sealing parts , to eliminate or reduce any of the factors that can prevent or reduce leakage , to achieve the purpose of sealing . Pressure pump design and the use of pressure is an objective can not be reduced , so that the pump is sealed to the solution to eliminate or reduce the gap between the seal faces . Such a gap includes a gap between the sealing surface and the sealing means within the gap Bunsen .
Mechanical seals
Modern shaft seal mechanical seal is the main method , though use of it is not easy to achieve completely leak , but the reach of tiny , it is perfectly acceptable amount of leakage is entirely possible. However, the operation of the pump , but often embarrassing situation, then the mechanical seal failure because what is it ?
1, the mechanical seal material selection inappropriate. Mechanical seal material and the transmission medium does not match. In operation, the sealing element will soon be corrosion, dissolution or wear , thus losing the sealing capability. Therefore, according to the nature of the transmission medium and the choice of the mechanical seal material is to ensure its sealing function and the normal life of the prerequisites.
2 , the mechanical seal flush condition does not meet the design requirements. In conveying easy to crystallize or fine particles of the medium , there must be a certain pressure and a certain flow of fluid to wash , or their crystals or particles will accelerate the sealing wear and affect the sealing of worn automatic compensation leak. Therefore, according to the nature of the transmission medium not only to configure the appropriate flushing lines , but also to install a monitoring and regulation instruments and devices to ensure that fluid pressure and flow to meet the design requirements, in order to maintain the normal operation of the mechanical seal , which is often overlooked by users .
3 , each of the mechanical seal can withstand the pressure is limited , due to the seal chamber pressure measurement are not allowed, resulting in the seal chamber pressure exceeds the mechanical seal can withstand the pressure of the leak , is a common sealing one reason for failure .
4 , the mechanical seal operating temperature can not exceed the specified value. In the design of a cooling circuit , often due to insufficient flow of the cooling medium leaving the cooling effect is reduced ; without the cooling circuit design, the numbered seals cavity often as harbored in the air and cause mechanical seal dry friction condition. In both cases, the movement of the mechanical seal sealing temperature is too high and accelerated wear, resulting in seal failure.
5 , the use of a single spring mechanical seals ignored when spring pump rotor rotation direction and the direction of rotation correct combination also occurs . Or design without instructions or assembly negligence , failed to do so because of the rotation of the rotor mechanical seal leaving but on the contrary increase the spring force , resulting in the ring and stationary ring friction pairs formed insufficient pressure leak .
6 , bearing severe wear or damage , so that axial movement of the shaft produce severe , but also one of the reasons mechanical seal leakage . With the scientific and technological development, new seals and sealing materials , emerging forms , which is bound to the pump seal technology have a direct impact and promoted. Long life, zero leakage pump products in a growing number of occasions to get promotion and application.
Oil seals
Self-tight seal is a lip fixed length plastic strap seal , its simple structure , small size , low cost , easy maintenance, resistance torque is small, both to prevent media leaks , but also to prevent external intrusion of dust and other harmful substances , but also to wear have a certain ability to compensate , but the impatience high pressure, it is generally used in low pressure applications. Seal should be installed in the manufacturing precision of h8 ~ h9, the surface roughness of 1.6 ~ 0.8μm and after surface hardening treatment of the shaft . Sealing medium should not contain solid particles and impurities , which will cause rapid wear of the shaft seal and leaving the seal failure.
Sealing butterfly valve with hard seal butterfly valve and use of the distinction
Valve seal means sealing the sides are rigid metallic material or other materials are called "hard seal ." This seal sealing performance is poor, but high temperature, abrasion resistance, good mechanical properties , such as : steel + steel ; steel + copper ; steel + graphite ; steel + alloy ; ( where steel may be cast iron, cast steel, alloy steel may be surfacing , spraying the alloy ) .
Soft sealing : sealing the sides of the metal material side , the other side there is a flexible non-metallic materials are called "soft seal ." This seal sealing performance is good, but not high temperature, easy to wear, mechanical poor , such as: steel + rubber ; steel + PTFE [wiki] polyethylene [/ wiki]; etc. soft sealing seat using a certain strength , hardness and heat resistance of non-metallic materials, good sealing performance, zero leakage can be done , but the life and relatively poor adaptability to temperature . Hard sealed with metal production, sealing performance is relatively poor , despite the manufacturers claim can be done zero leakage. Soft seal on the part of corrosive materials can not meet the technical requirements , the seal can be solved ! These two seals can complement each other , just in terms of soft seal tightness is relatively good , but now it is possible to seal tightness meet the corresponding requirements ! soft seal the advantage of good sealing performance , the disadvantage is easy to aging , wear, short life. Seal long life, but the relative tightness worse than the soft seal .
Their structural differences are mainly the following:
1, the structural differences : soft seal butterfly mostly in line more than a single eccentric hard sealing , double eccentric butterfly valve
2 , temperature : soft plastic seal for normal environments. Seal can be used for low temperature , room temperature , high temperature and other environmental
3 , pressure: soft sealing pressure - atmospheric pressure seal can also be used in high-pressure and other conditions
4 , the sealing performance: soft cargo seal and three eccentric hard sealing butterfly valve sealing performance is better, three eccentric butterfly valve in the high pressure high temperature environment can maintain a good seal.
In view of the above characteristics, soft seal butterfly valve for opening and closing the ventilation and dust piping bidirectional adjustment, water , light industry, petroleum, chemical and other industries. Hard seal butterfly valve used for heating, gas , and coal gas , oil, acid and alkali environment .
With the widespread use of butterfly valves , its easy installation, easy maintenance , simple structure features becoming increasingly apparent. Electric soft seal butterfly valve, pneumatic soft seal butterfly valve, hard seal butterfly valve in more and more places began to replace the electric gate valve, globe valve.
Soft sealing : sealing the sides of the metal material side , the other side there is a flexible non-metallic materials are called "soft seal ." This seal sealing performance is good, but not high temperature, easy to wear, mechanical poor , such as: steel + rubber ; steel + PTFE [wiki] polyethylene [/ wiki]; etc. soft sealing seat using a certain strength , hardness and heat resistance of non-metallic materials, good sealing performance, zero leakage can be done , but the life and relatively poor adaptability to temperature . Hard sealed with metal production, sealing performance is relatively poor , despite the manufacturers claim can be done zero leakage. Soft seal on the part of corrosive materials can not meet the technical requirements , the seal can be solved ! These two seals can complement each other , just in terms of soft seal tightness is relatively good , but now it is possible to seal tightness meet the corresponding requirements ! soft seal the advantage of good sealing performance , the disadvantage is easy to aging , wear, short life. Seal long life, but the relative tightness worse than the soft seal .
Their structural differences are mainly the following:
1, the structural differences : soft seal butterfly mostly in line more than a single eccentric hard sealing , double eccentric butterfly valve
2 , temperature : soft plastic seal for normal environments. Seal can be used for low temperature , room temperature , high temperature and other environmental
3 , pressure: soft sealing pressure - atmospheric pressure seal can also be used in high-pressure and other conditions
4 , the sealing performance: soft cargo seal and three eccentric hard sealing butterfly valve sealing performance is better, three eccentric butterfly valve in the high pressure high temperature environment can maintain a good seal.
In view of the above characteristics, soft seal butterfly valve for opening and closing the ventilation and dust piping bidirectional adjustment, water , light industry, petroleum, chemical and other industries. Hard seal butterfly valve used for heating, gas , and coal gas , oil, acid and alkali environment .
With the widespread use of butterfly valves , its easy installation, easy maintenance , simple structure features becoming increasingly apparent. Electric soft seal butterfly valve, pneumatic soft seal butterfly valve, hard seal butterfly valve in more and more places began to replace the electric gate valve, globe valve.
2013年9月11日星期三
Centrifugal pump mechanical seal leakage causes operation and installation errors
First, the normal operation of a sudden leak. Centrifugal pumps in operation suddenly leaking a few are due to normal wear and tear or has reached the end , but mostly due to large changes in working conditions , operation or maintenance caused by improper .
1 , taking the time , cavitation or longer hold pressure , resulting in seal damage ;
2 , the actual output of the pump is too small, a large number of medium circulation pump , heat build-up , causing the gasification medium , resulting in seal failure ;
3, the return flow is too large , causing suction tube side of the container ( tower, kettle , pot, pool ) at the bottom dregs , damaged seals ;
4 , for a long time outage, restart without manual turning , friction due to adhesion and tearing sealing surface ;
5, the corrosive medium , the polymerizable , gumming material increased;
6, the dramatic changes in the ambient temperature ;
7 , or adjustment of operating conditions change frequently ;
8 , such as a sudden power outage or downtime . Centrifugal sudden leak in normal operation , if not in time, often lead to more accidents or loss shall be seriously and take effective measures .
Second, pump mechanical seal Overhaul Mistakes
1 , the greater the amount of compression spring seal better. In actual fact , the spring compression excessive friction can cause rapid wear , instantly burning ; excessive compression of the spring to lose the ability to adjust the ring face , resulting in seal failure.
2 , the sealing ring diagram tighter, the better . In fact, ring seals tight harm than good. First exacerbate inter- ring and sleeve wear, premature leakage ; Second, increasing the axial adjustment ring , the resistance movement , frequent changes in operating conditions can not make timely adjustments ; Third spring excessive fatigue easily damaged ; four is to make the ring seal deformation, affecting the sealing effect.
3, the stationary ring seals tight as possible . Stationary ring seals basically at a standstill , the effect will be relatively tight seal better, but too tight is harmful. One cause static ring seals due to excessive deformation, affecting the sealing effect ; Second, the majority of graphite stationary ring material , generally more brittle , excessive force can easily cause fragmentation ; three is to install , difficult to remove , easy to damage the stationary ring .
4 , impeller lock nut tight as possible . Mechanical bolt seal leakage , the leakage between the sleeve and the shaft ( shaft between the leak ) is relatively common . Generally, the impeller shaft between the leak is not locking the lock master , in fact, lead to leakage between axes many factors , such as the failure of inter-axis pad , offset , there are impurities between axes , with the shaft and sleeve at a larger shape bit error , the contact surface damage , there is a gap between the shaft parts , threaded shaft is too long , and this will lead to leakage between the shafts . Lock nut locking pad between axes can only lead to excessive premature failure , contrary moderate lock locked mother , so that the shaft between the pads always maintain a certain degree of compression flexibility in operation will be automatically timely lock nut locking , so that the shaft is always in a good inter- the sealed state .
5 , the new better than the old . In contrast, using the new mechanical seal better than the old , but the new mechanical seal quality or choice of material is not the time , with the larger size of the error will affect the sealing effect ; and permeability in the polymerization medium, the stationary ring without excessive wear, or not to replace as well. Because static ring stationary ring seat for a long time in a quiescent state , the polymer and impurities deposited as a whole, played a good seal.
6 , do not split overhaul than good . Once the mechanical wire seals leakage will be eager to overhaul , in fact , sometimes sealed and not damaged , simply adjust the working conditions or the seals can be adjusted to eliminate leakage. This way to avoid waste and can verify their fault judgment ability , and accumulated experience in maintenance to improve the quality of maintenance .
1 , taking the time , cavitation or longer hold pressure , resulting in seal damage ;
2 , the actual output of the pump is too small, a large number of medium circulation pump , heat build-up , causing the gasification medium , resulting in seal failure ;
3, the return flow is too large , causing suction tube side of the container ( tower, kettle , pot, pool ) at the bottom dregs , damaged seals ;
4 , for a long time outage, restart without manual turning , friction due to adhesion and tearing sealing surface ;
5, the corrosive medium , the polymerizable , gumming material increased;
6, the dramatic changes in the ambient temperature ;
7 , or adjustment of operating conditions change frequently ;
8 , such as a sudden power outage or downtime . Centrifugal sudden leak in normal operation , if not in time, often lead to more accidents or loss shall be seriously and take effective measures .
Second, pump mechanical seal Overhaul Mistakes
1 , the greater the amount of compression spring seal better. In actual fact , the spring compression excessive friction can cause rapid wear , instantly burning ; excessive compression of the spring to lose the ability to adjust the ring face , resulting in seal failure.
2 , the sealing ring diagram tighter, the better . In fact, ring seals tight harm than good. First exacerbate inter- ring and sleeve wear, premature leakage ; Second, increasing the axial adjustment ring , the resistance movement , frequent changes in operating conditions can not make timely adjustments ; Third spring excessive fatigue easily damaged ; four is to make the ring seal deformation, affecting the sealing effect.
3, the stationary ring seals tight as possible . Stationary ring seals basically at a standstill , the effect will be relatively tight seal better, but too tight is harmful. One cause static ring seals due to excessive deformation, affecting the sealing effect ; Second, the majority of graphite stationary ring material , generally more brittle , excessive force can easily cause fragmentation ; three is to install , difficult to remove , easy to damage the stationary ring .
4 , impeller lock nut tight as possible . Mechanical bolt seal leakage , the leakage between the sleeve and the shaft ( shaft between the leak ) is relatively common . Generally, the impeller shaft between the leak is not locking the lock master , in fact, lead to leakage between axes many factors , such as the failure of inter-axis pad , offset , there are impurities between axes , with the shaft and sleeve at a larger shape bit error , the contact surface damage , there is a gap between the shaft parts , threaded shaft is too long , and this will lead to leakage between the shafts . Lock nut locking pad between axes can only lead to excessive premature failure , contrary moderate lock locked mother , so that the shaft between the pads always maintain a certain degree of compression flexibility in operation will be automatically timely lock nut locking , so that the shaft is always in a good inter- the sealed state .
5 , the new better than the old . In contrast, using the new mechanical seal better than the old , but the new mechanical seal quality or choice of material is not the time , with the larger size of the error will affect the sealing effect ; and permeability in the polymerization medium, the stationary ring without excessive wear, or not to replace as well. Because static ring stationary ring seat for a long time in a quiescent state , the polymer and impurities deposited as a whole, played a good seal.
6 , do not split overhaul than good . Once the mechanical wire seals leakage will be eager to overhaul , in fact , sometimes sealed and not damaged , simply adjust the working conditions or the seals can be adjusted to eliminate leakage. This way to avoid waste and can verify their fault judgment ability , and accumulated experience in maintenance to improve the quality of maintenance .
Experts tell you do choose plastic window seal
Leakage leaking sealant seals at play
"I lived on the 9th floor , the house has lived for six years, recent heavy rains , many places are leaking windows , and ventilation is very serious, how is this going ? " Ms. Hou , who lives in intimate garden advice .
Experts say : It is Door Changchun Da Wang Jinhong manager introduced into July , Changchun temperature surge, but sooner or later the temperature difference is quite large , mutant temperature makes general quality steel windows stretching more obvious , especially in the window sealant, rail car seals after a heavy rain, exposure and other reasons , making the glass and sash seal tightly enough to appear leakage leaking situation. Consumers can check their own windows, first check whether there is sediment drain , clean-up if it is missing , we should replace the seals and a large area of sealant . Second seal and sealant replacement to note that these small pieces of quality vary widely , a good seal can be used on 2078 , or even ten years are no problems, and poor quality may 2023 will be aging . Window sealant , too, generally imported glue to better seal the wall and window frames , no leakage , winter warmth, no air leakage . Poor quality sealant will shrink after Enthusiasm , or even fall off .
Fog cover insulating glass windows are leaking due to
"My family is opposite a large ecological park , but recently the bedroom window somehow a large area of fog , mist between two layers of glass , not simply wipe the park landscape of sight ." Zhou , who lives in city wide she says.
Experts : City Engineering Manager Jiang Hao others pointed out , this situation is because steel windows hollow glass leak caused , if shelf life has expired , only to replace the glass . Replacement to a regular manufacturers to buy , because regular steel window factory specialized in the production , the use of large machines repression, evacuated of air between the glass are basically machine operation , and some small handicraft workshop , the majority or in manual-based , difficult to ensure quality, double-glazed security seals sealant will be breathable. Consumers are choosing steel window making factory , it is best to look at its factory site to see if there are relevant certificates , whether the technology is clearance. Secondly, they have a lot to the owners has produced a good windows, consumers can look carefully at whether the clearance of their craft , handled the details of the connection is fine and smooth, whether seals pores and so on. Third, if the conditions , the consumer can field their construction site to see .
Defective serious security risk profiles
"I lived in a 12-story , yang side floor bedroom is large windows , the sash is very large. Recent heavy winds, steel window frames were blown straight drum , looking quite startling . Heavy downpour , looking for professional inspection , startled , the original large windows so many places that are not lined , Zai Yu wind, really disastrous consequences ! " Mr. Zheng to the newspaper .
Experts say : Fund Manager pointed out that most problems are steel window steel liner thickness unqualified or without liner , followed actuator angle chain failed, sealing tape aging, a pull on the crack or fracture , then there is some small workshops windows with plastic from the other removed to the "second-hand goods", reprocessed into windows . Small workshop processing steel window factory itself is a problem , coupled with cut corners , shoddy deceive means to cause new for steel windows appear breathable, water seepage, no wind force and other quality problems . After a market test of the brand really only a few , but these profiles OEM brand is also very much , consumers must be careful when steel windows , it is best to have scale , professional manufacturers purchase .
In addition, steel window design and installation process is also very important, such as the height of the middle frame to take a more appropriate value at least equal to the height of the upper and lower beams . When the box width of 1.5 meters, the window may be considered without vertical transom beam , when the frame width of 1.8 meters , then the window to add vertical transom beam . These designs are very particular about not only beautiful, but also windproof and warm.
In the installation , the regular scale factories have professional home design for home owners in the specific circumstances of the original windows or balconies at the construction, whether to use steel, how to install the liner , how to punch drilling has relevant norms and acceptance.
"I lived on the 9th floor , the house has lived for six years, recent heavy rains , many places are leaking windows , and ventilation is very serious, how is this going ? " Ms. Hou , who lives in intimate garden advice .
Experts say : It is Door Changchun Da Wang Jinhong manager introduced into July , Changchun temperature surge, but sooner or later the temperature difference is quite large , mutant temperature makes general quality steel windows stretching more obvious , especially in the window sealant, rail car seals after a heavy rain, exposure and other reasons , making the glass and sash seal tightly enough to appear leakage leaking situation. Consumers can check their own windows, first check whether there is sediment drain , clean-up if it is missing , we should replace the seals and a large area of sealant . Second seal and sealant replacement to note that these small pieces of quality vary widely , a good seal can be used on 2078 , or even ten years are no problems, and poor quality may 2023 will be aging . Window sealant , too, generally imported glue to better seal the wall and window frames , no leakage , winter warmth, no air leakage . Poor quality sealant will shrink after Enthusiasm , or even fall off .
Fog cover insulating glass windows are leaking due to
"My family is opposite a large ecological park , but recently the bedroom window somehow a large area of fog , mist between two layers of glass , not simply wipe the park landscape of sight ." Zhou , who lives in city wide she says.
Experts : City Engineering Manager Jiang Hao others pointed out , this situation is because steel windows hollow glass leak caused , if shelf life has expired , only to replace the glass . Replacement to a regular manufacturers to buy , because regular steel window factory specialized in the production , the use of large machines repression, evacuated of air between the glass are basically machine operation , and some small handicraft workshop , the majority or in manual-based , difficult to ensure quality, double-glazed security seals sealant will be breathable. Consumers are choosing steel window making factory , it is best to look at its factory site to see if there are relevant certificates , whether the technology is clearance. Secondly, they have a lot to the owners has produced a good windows, consumers can look carefully at whether the clearance of their craft , handled the details of the connection is fine and smooth, whether seals pores and so on. Third, if the conditions , the consumer can field their construction site to see .
Defective serious security risk profiles
"I lived in a 12-story , yang side floor bedroom is large windows , the sash is very large. Recent heavy winds, steel window frames were blown straight drum , looking quite startling . Heavy downpour , looking for professional inspection , startled , the original large windows so many places that are not lined , Zai Yu wind, really disastrous consequences ! " Mr. Zheng to the newspaper .
Experts say : Fund Manager pointed out that most problems are steel window steel liner thickness unqualified or without liner , followed actuator angle chain failed, sealing tape aging, a pull on the crack or fracture , then there is some small workshops windows with plastic from the other removed to the "second-hand goods", reprocessed into windows . Small workshop processing steel window factory itself is a problem , coupled with cut corners , shoddy deceive means to cause new for steel windows appear breathable, water seepage, no wind force and other quality problems . After a market test of the brand really only a few , but these profiles OEM brand is also very much , consumers must be careful when steel windows , it is best to have scale , professional manufacturers purchase .
In addition, steel window design and installation process is also very important, such as the height of the middle frame to take a more appropriate value at least equal to the height of the upper and lower beams . When the box width of 1.5 meters, the window may be considered without vertical transom beam , when the frame width of 1.8 meters , then the window to add vertical transom beam . These designs are very particular about not only beautiful, but also windproof and warm.
In the installation , the regular scale factories have professional home design for home owners in the specific circumstances of the original windows or balconies at the construction, whether to use steel, how to install the liner , how to punch drilling has relevant norms and acceptance.
VRLA batteries four conditions of a hermetic seal
Well known in the battery manufacturing process , tight sealing is to prevent the battery from the loss of moisture during storage and decrease in capacity , to prevent the green copper cap and ensure that no water in the use of the important measures grout . Tight vehicle cargo seal with the battery discharge level of performance , leak-proof performance and storage performance solidarity . Sealing the battery to prevent intrusion of oxygen in the air inside the battery , accelerated corrosion of zinc . Therefore , in order to ensure the quality of the battery , it is necessary to strengthen seal.
When they meet the following four conditions , sealed VRLA batteries can be achieved .
1 ) Negative grid with no antimony lead-calcium alloy to improve the cathode overpotential , which is to improve gas precipitation threshold voltage , according to estimates using lead-calcium alloy than the low antimony alloy high 200mv precipitation gases. Inhibiting the precipitation of hydrogen , with a certain internal pressure . And there is a very strong corrosion resistance.
2 ) using a special one-way valve , the internal pressure of the battery to maintain a certain balance , and to suppress the outside air (O2) from entering the battery negative grid corrosion , trailer seals the valve opening pressure of 18-23Kpa, valve closing pressure of not less 8Kpa, and there filter acid tablets to maintain a certain electrolyte concentration .
3) The porosity of more than 90% ultra-fine glass fiber separator , a certain amount of adsorption of the electrolyte , to lean solution design , and sufficient gas passage , the gas can internally complex .
4) The negative plate active material 10% excess , of oxygen is sufficient to precipitate the composite positive electrode , the negative electrode reaction is always in charge , to prevent hydrogen and salinization .
When they meet the following four conditions , sealed VRLA batteries can be achieved .
1 ) Negative grid with no antimony lead-calcium alloy to improve the cathode overpotential , which is to improve gas precipitation threshold voltage , according to estimates using lead-calcium alloy than the low antimony alloy high 200mv precipitation gases. Inhibiting the precipitation of hydrogen , with a certain internal pressure . And there is a very strong corrosion resistance.
2 ) using a special one-way valve , the internal pressure of the battery to maintain a certain balance , and to suppress the outside air (O2) from entering the battery negative grid corrosion , trailer seals the valve opening pressure of 18-23Kpa, valve closing pressure of not less 8Kpa, and there filter acid tablets to maintain a certain electrolyte concentration .
3) The porosity of more than 90% ultra-fine glass fiber separator , a certain amount of adsorption of the electrolyte , to lean solution design , and sufficient gas passage , the gas can internally complex .
4) The negative plate active material 10% excess , of oxygen is sufficient to precipitate the composite positive electrode , the negative electrode reaction is always in charge , to prevent hydrogen and salinization .
STP guard shield with superior sealing performance
We all know that driving on the highway often because of the tightness of the car loud enough to cause , serious impact on car owners driving. So the car noise is particularly important modifications , security seals as choose what kind of products, Here I will introduce STP ALUM (STP guard shield ) , with superior sealing performance.
STP guard shield is a thin plate , 0.2mm thick aluminum foil and the adhesive layer consisting of butyl product . The most suitable temperature range of -45 ℃ to -70 ℃. Waterproof, anti-corrosion and sealing characteristics. Can be easily installed in a variety of surfaces , and the installation process does not require heating . This material is mainly for sound systems installed in different parts of the vehicle prior to sealing , waterproof labels mainly used in the door panels .
It is reported , STP products are used Russian military technology , full of Russian manufacture . Size of packaging and sizes 3 / pack, large pack size (500X750mm = 0.375m2). Small package size (500X750mm = 0.375m2) products must be stored in vertical height shall not exceed 1.5 meters airtight room, at least one meter away from heating equipment , avoid moisture , oil and gas and direct sunlight . If the storage room is not warm enough , you can put the material before use +5 stored at 20 degrees Celsius in the room less than 24 hours.
STP guard shield is a thin plate , 0.2mm thick aluminum foil and the adhesive layer consisting of butyl product . The most suitable temperature range of -45 ℃ to -70 ℃. Waterproof, anti-corrosion and sealing characteristics. Can be easily installed in a variety of surfaces , and the installation process does not require heating . This material is mainly for sound systems installed in different parts of the vehicle prior to sealing , waterproof labels mainly used in the door panels .
It is reported , STP products are used Russian military technology , full of Russian manufacture . Size of packaging and sizes 3 / pack, large pack size (500X750mm = 0.375m2). Small package size (500X750mm = 0.375m2) products must be stored in vertical height shall not exceed 1.5 meters airtight room, at least one meter away from heating equipment , avoid moisture , oil and gas and direct sunlight . If the storage room is not warm enough , you can put the material before use +5 stored at 20 degrees Celsius in the room less than 24 hours.
2013年9月9日星期一
Sealing performance is to solve the key problem of transformer oil leakage
In recent years , through the main transformer and auxiliary transformer Oil Leak processing , continuous improvement , summarize prevention measures , transformer oil leakage rate is greatly reduced for the safe operation of the transformer to provide a guarantee for the enterprise , social, and users get economic efficiency.
1 , select the material good seals
Transformer maintenance and handling leakage should be selected high temperature, excellent oil resistant metal cable ties. Domestic transformer industry, the most commonly used seal material is nitrile rubber , oil resistance depends mainly on its acrylonitrile content of nitrile rubber , acrylonitrile content is higher, the better oil resistance , hardness , the more easily deformed. Generally Shore hardness should be selected between 70 to 80 nitrile rubber . Identification oil resistant gasket , the general aging test should be done and the gasket and compatibility testing of transformer oil , to be immersed in the hot oil 120 ℃ 168h, and measuring its weight , volume and rate of change of hardness , select its little deformation , standards-compliant security seal.
2, choose high-quality butterfly
Select ZF80 vacuum eccentric butterfly valve . Compared with the ordinary valve , vacuum butterfly valve in the mechanical strength , surface finish has been greatly improved, and that it also has one of the biggest advantage is that the transformer flange interface uses a double-sealed , so put an end to transformer oil leakage at the interface problem .
3 , the use of welding plugging
For the left to the transformer due to casting porosity, trachoma , weld , solder joint appearance of Weld , Desoldering , crack , the available welding for plugging. In the blocking should identify leaks before welding , smaller leaks will drain directly Welded little dead ; leak should be filled with the larger asbestos rope or metal filler , and then surfacing in four weeks , and then using a small electrode high-current fast arc welding .
1 , select the material good seals
Transformer maintenance and handling leakage should be selected high temperature, excellent oil resistant metal cable ties. Domestic transformer industry, the most commonly used seal material is nitrile rubber , oil resistance depends mainly on its acrylonitrile content of nitrile rubber , acrylonitrile content is higher, the better oil resistance , hardness , the more easily deformed. Generally Shore hardness should be selected between 70 to 80 nitrile rubber . Identification oil resistant gasket , the general aging test should be done and the gasket and compatibility testing of transformer oil , to be immersed in the hot oil 120 ℃ 168h, and measuring its weight , volume and rate of change of hardness , select its little deformation , standards-compliant security seal.
2, choose high-quality butterfly
Select ZF80 vacuum eccentric butterfly valve . Compared with the ordinary valve , vacuum butterfly valve in the mechanical strength , surface finish has been greatly improved, and that it also has one of the biggest advantage is that the transformer flange interface uses a double-sealed , so put an end to transformer oil leakage at the interface problem .
3 , the use of welding plugging
For the left to the transformer due to casting porosity, trachoma , weld , solder joint appearance of Weld , Desoldering , crack , the available welding for plugging. In the blocking should identify leaks before welding , smaller leaks will drain directly Welded little dead ; leak should be filled with the larger asbestos rope or metal filler , and then surfacing in four weeks , and then using a small electrode high-current fast arc welding .
How to choose the cable sealing modules
1 The right choice of supplier
Choice of supplier , you should choose a professional cable glands module suppliers , preferably in a cable gland for the main business activities of the manufacturers . Manufacturers should have some experience in industrial applications , understanding of the product market applications. The current market was mixed good and bad cable glands , especially the large number of dealers on the network information posted to our choice of suppliers to bring a certain degree of difficulty.
The author believes that an excellent cable sealing module manufacturers should have the following points , A. Cable sealing modules are its main business ; B. Qualification sound and stability office space, not just a few information posted online , casual leave a contact ; C. independent company website and product physical map , a lot of other company 's products stolen map ( or PS pictures ) , virtually no product and service capabilities ; D. able to provide customers a complete professional CAD drawings and quotes , rather than simply a casual quotations ; E. and customer should have good communication skills , customer product selection and design rationalization proposals , of course, this requires some practical experience .
2 The right choice of products
Correct choice of products, should pay attention to the following aspects:
2.1 Module options: module is divided into 30 mm long and 60 mm in length both in different lengths and maybe also the entire thickness of the sealing device . Thus, the general run cable through the cabin deck , cables through walls and other heavy objects selected 60 mm long modules. The cable through the cabinet or other thin object, generally choose 30 mm long modules , while the entire sealing device is thin and light .
2.2 sealing frame choice: sealing frame is determined by the strap seals modules with different specifications and number of modules determines the appropriate sealing frame . Across the deck and the cabin walls and other objects should be selected 60 mm thick frame , materials generally have two kinds of low carbon steel and stainless steel . Recommended depending on the application environment choose a different frame materials. Recommended to choose the stainless steel frame , because the general cable sealing modules are outdoor or indoor environments outside connections, generally dark and damp or in sunlight exposure . Once the sealing frame with rust corrosion is occurring, will directly affect the performance and life of the sealing module , and seriously affect the whole sealing means sealing protective effect.
2.3 clamping block and the spacer plate material selection : General cable sealsupplier in the clamping block and compartment plate material on both stainless steel and mild steel in both materials can be selected . I do not recommend choosing low- carbon steel clamping blocks and spacer plates, because both kinds of material cost difference is not great , but life is very different , do not lose the greater.
2.4 The use of grease : It is recommended strict accordance with product installation instructions to use grease , many times in order to improve the efficiency of workers in trouble , do not use or less use grease, actually greatly affected the overall sealing means sealing effect .
2.5 About Installation tools: general project is not recommended. Engineering projects larger than recommended a compactor on it, only in the maintenance and reconstruction of puller only be used to time . Many manufacturers generally put a full installation tool as essential goods sold to customers , the actual increase customer acquisition costs .
About aside : Under normal circumstances proposed to set aside 30-40 % , of course, if the project is implemented in phases necessary special consideration. Also do not recommend the use of solid module as set aside , because this part of the procurement cost savings temporarily , but the actual change is the need for secondary procurement, not only a waste , and increased costs.
Choice of supplier , you should choose a professional cable glands module suppliers , preferably in a cable gland for the main business activities of the manufacturers . Manufacturers should have some experience in industrial applications , understanding of the product market applications. The current market was mixed good and bad cable glands , especially the large number of dealers on the network information posted to our choice of suppliers to bring a certain degree of difficulty.
The author believes that an excellent cable sealing module manufacturers should have the following points , A. Cable sealing modules are its main business ; B. Qualification sound and stability office space, not just a few information posted online , casual leave a contact ; C. independent company website and product physical map , a lot of other company 's products stolen map ( or PS pictures ) , virtually no product and service capabilities ; D. able to provide customers a complete professional CAD drawings and quotes , rather than simply a casual quotations ; E. and customer should have good communication skills , customer product selection and design rationalization proposals , of course, this requires some practical experience .
2 The right choice of products
Correct choice of products, should pay attention to the following aspects:
2.1 Module options: module is divided into 30 mm long and 60 mm in length both in different lengths and maybe also the entire thickness of the sealing device . Thus, the general run cable through the cabin deck , cables through walls and other heavy objects selected 60 mm long modules. The cable through the cabinet or other thin object, generally choose 30 mm long modules , while the entire sealing device is thin and light .
2.2 sealing frame choice: sealing frame is determined by the strap seals modules with different specifications and number of modules determines the appropriate sealing frame . Across the deck and the cabin walls and other objects should be selected 60 mm thick frame , materials generally have two kinds of low carbon steel and stainless steel . Recommended depending on the application environment choose a different frame materials. Recommended to choose the stainless steel frame , because the general cable sealing modules are outdoor or indoor environments outside connections, generally dark and damp or in sunlight exposure . Once the sealing frame with rust corrosion is occurring, will directly affect the performance and life of the sealing module , and seriously affect the whole sealing means sealing protective effect.
2.3 clamping block and the spacer plate material selection : General cable sealsupplier in the clamping block and compartment plate material on both stainless steel and mild steel in both materials can be selected . I do not recommend choosing low- carbon steel clamping blocks and spacer plates, because both kinds of material cost difference is not great , but life is very different , do not lose the greater.
2.4 The use of grease : It is recommended strict accordance with product installation instructions to use grease , many times in order to improve the efficiency of workers in trouble , do not use or less use grease, actually greatly affected the overall sealing means sealing effect .
2.5 About Installation tools: general project is not recommended. Engineering projects larger than recommended a compactor on it, only in the maintenance and reconstruction of puller only be used to time . Many manufacturers generally put a full installation tool as essential goods sold to customers , the actual increase customer acquisition costs .
About aside : Under normal circumstances proposed to set aside 30-40 % , of course, if the project is implemented in phases necessary special consideration. Also do not recommend the use of solid module as set aside , because this part of the procurement cost savings temporarily , but the actual change is the need for secondary procurement, not only a waste , and increased costs.
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