8 pm, Mengjin County Baihe Town territory Zhengsan Gong Lu Meng Road, near the buckle tanker spill occurred , but fortunately no casualties .
16:00 the day before , container seals a formaldehyde solution tanker transportation in Bangladesh village a big buckle road slope sections Mizoguchi leak , the county public security fire department rushed to the scene after the alarm .
Police on the scene saw the leaked formaldehyde solution to form a ditch along the roadside about 400 meters and a width of 1 meter trickle. In the relevant departments under the coordination of the car belongs transferred to another car company vehicle accidents within the formaldehyde solution pumped . Field staff to disclose rubbed salt formaldehyde solution and covered with mud after clearing, collection .
It is understood that the car is equipped with 10 tons of formaldehyde solution , because the tanker at the bottom of a valve gasket is damaged, resulting inside about 300 kg , containing 30% aqueous solution of formaldehyde leak. Formaldehyde is a kind of colorless gas with strong pungent odor , soluble in water , alcohol and ether .self-locking cable ties Formaldehyde is gaseous at room temperature , usually in the form of an aqueous solution .
Currently, the leaked scene disposal, the road returned to normal traffic .
pull tight security seals
pull tight security seals
2013年10月31日星期四
Valve gasket damaged damaged bitter pit large tanker drivers
8 pm, Mengjin County Baihe Town territory Zhengsan Gong Lu Meng Road, near the buckle tanker spill occurred , but fortunately no casualties .
16:00 the day before , container seals a formaldehyde solution tanker transportation in Bangladesh village a big buckle road slope sections Mizoguchi leak , the county public security fire department rushed to the scene after the alarm .
Police on the scene saw the leaked formaldehyde solution to form a ditch along the roadside about 400 meters and a width of 1 meter trickle. In the relevant departments under the coordination of the car belongs transferred to another car company vehicle accidents within the formaldehyde solution pumped . Field staff to disclose rubbed salt formaldehyde solution and covered with mud after clearing, collection .
It is understood that the car is equipped with 10 tons of formaldehyde solution , because the tanker at the bottom of a valve gasket is damaged, resulting inside about 300 kg , containing 30% aqueous solution of formaldehyde leak. Formaldehyde is a kind of colorless gas with strong pungent odor , soluble in water , alcohol and ether .self-locking cable ties Formaldehyde is gaseous at room temperature , usually in the form of an aqueous solution .
Currently, the leaked scene disposal, the road returned to normal traffic .
16:00 the day before , container seals a formaldehyde solution tanker transportation in Bangladesh village a big buckle road slope sections Mizoguchi leak , the county public security fire department rushed to the scene after the alarm .
Police on the scene saw the leaked formaldehyde solution to form a ditch along the roadside about 400 meters and a width of 1 meter trickle. In the relevant departments under the coordination of the car belongs transferred to another car company vehicle accidents within the formaldehyde solution pumped . Field staff to disclose rubbed salt formaldehyde solution and covered with mud after clearing, collection .
It is understood that the car is equipped with 10 tons of formaldehyde solution , because the tanker at the bottom of a valve gasket is damaged, resulting inside about 300 kg , containing 30% aqueous solution of formaldehyde leak. Formaldehyde is a kind of colorless gas with strong pungent odor , soluble in water , alcohol and ether .self-locking cable ties Formaldehyde is gaseous at room temperature , usually in the form of an aqueous solution .
Currently, the leaked scene disposal, the road returned to normal traffic .
Wafer soft seal butterfly valve characteristics
New features and butterfly valve in the course of a problem :
Currently, soft seal butterfly valve as a piping system used to achieve off and flow control components, has been in the petroleum, chemical, metallurgy, water and electricity , and many other fields has been very widely used . In the well-known butterfly valve technology , the sealing forms enclosed structure, sealing material for rubber , PTFE and so on. Restrictions due to structural features , suited high temperature, high pressure and corrosion resistance, abrasion resistance and other industries. Present a more advanced butterfly valve is a three eccentricity metal hard luggage seals butterfly valve, valve and seat components for the piece , seat sealing surface layer welding temperature, corrosion resistant alloys. Multilayer soft stacked ring fixed to the valve plate, this butterfly valve in comparison with the conventional high temperature , easy operation, open and close without friction, closed with the transmission of the torque increases to compensate for sealing , improved valve sealing performance and durability advantages .
One , as soft and hard stacked ring fixed in the valve plate, when the valve plate normally open state media, the formation of a positive sealing surface erosion, metal sheets laminated in soft sealing tape subject to erosion , direct impact on seal performance.
Second, by the structural constraints of the structure do not meet the following diameter DN200 valves, because the overall structure of the valve plate is too thick, large flow resistance .
Third, because the principle of three eccentric structure , the sealing surface of the valve plate seal between the valve seat is on the transmission of torque to the valve plate is pressed against the valve seat . Positive flow state, the higher the pressure medium sealed tight squeeze . When the flow channel upstream medium with media pressure valve plate and valve seat pressure between the units is less than the medium pressure, the security stickers started to leak .
Currently, soft seal butterfly valve as a piping system used to achieve off and flow control components, has been in the petroleum, chemical, metallurgy, water and electricity , and many other fields has been very widely used . In the well-known butterfly valve technology , the sealing forms enclosed structure, sealing material for rubber , PTFE and so on. Restrictions due to structural features , suited high temperature, high pressure and corrosion resistance, abrasion resistance and other industries. Present a more advanced butterfly valve is a three eccentricity metal hard luggage seals butterfly valve, valve and seat components for the piece , seat sealing surface layer welding temperature, corrosion resistant alloys. Multilayer soft stacked ring fixed to the valve plate, this butterfly valve in comparison with the conventional high temperature , easy operation, open and close without friction, closed with the transmission of the torque increases to compensate for sealing , improved valve sealing performance and durability advantages .
One , as soft and hard stacked ring fixed in the valve plate, when the valve plate normally open state media, the formation of a positive sealing surface erosion, metal sheets laminated in soft sealing tape subject to erosion , direct impact on seal performance.
Second, by the structural constraints of the structure do not meet the following diameter DN200 valves, because the overall structure of the valve plate is too thick, large flow resistance .
Third, because the principle of three eccentric structure , the sealing surface of the valve plate seal between the valve seat is on the transmission of torque to the valve plate is pressed against the valve seat . Positive flow state, the higher the pressure medium sealed tight squeeze . When the flow channel upstream medium with media pressure valve plate and valve seat pressure between the units is less than the medium pressure, the security stickers started to leak .
2013年10月28日星期一
Currently on the market often posing Corner There are three types of plastic glue
Strength aluminum alloy doors and sealing the corners of aluminum doors and windows as long as the use of special glue to set angle, but unfortunately most of the windows and doors factory and developers, as well as related administrative departments architectural design, supervision and other units did not really recognize the special Corner plastic windows and doors in improving the overall quality of the important role. Some assembly plant doors and windows do not use glue or wrongly Corner glass adhesive, structural adhesive, such as epoxy glue aluminum doors and windows dedicated Corner glue in use. Currently on the market often posing Corner adhesive glue into three categories:
1, glass, plastic, also known as silicone sealant; poor adhesion on aluminum, poor weather, easy to aging, low hardness, elasticity is too large, curing gel does not swell, can not make the corner yard stick closely with the cavity then become one.
2, structural adhesive for bonding aluminum poor, long curing time, products and more smell, does not swell when cured, can not produce high strength.
3, after curing epoxy adhesive inelastic, unable to adapt to the form of microseismic, easy crisp and broken, Corner after long-term strength is not enough, will produce cracking, dregs phenomenon.
Why do we have to use a dedicated advocate Corner gum? Because of special aluminum alloy doors and windows Corner glue has the following characteristics:
1, colloids are modified polyurethane-based adhesives, solvent-free, in line with environmental requirements.
2, initial curing time is short, about 10 minutes, will help improve production efficiency. Divided into single, two-component two kinds, more suitable for "Corner glue and corner connectors dispensing whole" two kinds of process requirements.
3, high hardness after curing, but not brittle, with low elasticity and excellent waterproof performance, so that angle code and section ductile adhesive wall connections, which make up, various parts of the corner of the window to reduce deformation, cracking conditions an effective solution to the problem of leakage corner windows and doors.
4, one-component adhesive glue is completely cured Corner, Corner profiles cavity with an effective part of the shear strength of the adhesive can be achieved 10.3N/MM2, component Corner Shear strength can reach 18N/MM2, greatly enhanced strength corner of the window. That is, ordinary 60 series of profiles of the shear strength can exceed Cutaway.
5, colloidal slightly foaming during the curing process, expanded, forming metal to metal between the elastic pad, the effective transmission of forces weaken, play a shock, the cushion effect.
6, weather resistance, the ability of -40 ° C +80 ° C temperature variation, white or translucent gel, the gel will not play in the short yellow. Corner two-component glue in 230 ° C high temperature tolerance of 30 minutes, suitable for powder coating and other post-processing needs.
7, with special cleaning agent with a small amount of excess glue is easy to clean,Fixed Length plastic seals will not harm the surface profile of the coating and paint, environmental non-toxic.
The author believes that the current market a lot to promote the use of the German "Wei Shi" series Corner combination of gum and related ancillary products, aluminum doors and windows corner for structural reinforcement and sealed professionally designed to meet the requirements of various groups angle is aluminum door and window factory and the developers of the most sensible choice.
1, glass, plastic, also known as silicone sealant; poor adhesion on aluminum, poor weather, easy to aging, low hardness, elasticity is too large, curing gel does not swell, can not make the corner yard stick closely with the cavity then become one.
2, structural adhesive for bonding aluminum poor, long curing time, products and more smell, does not swell when cured, can not produce high strength.
3, after curing epoxy adhesive inelastic, unable to adapt to the form of microseismic, easy crisp and broken, Corner after long-term strength is not enough, will produce cracking, dregs phenomenon.
Why do we have to use a dedicated advocate Corner gum? Because of special aluminum alloy doors and windows Corner glue has the following characteristics:
1, colloids are modified polyurethane-based adhesives, solvent-free, in line with environmental requirements.
2, initial curing time is short, about 10 minutes, will help improve production efficiency. Divided into single, two-component two kinds, more suitable for "Corner glue and corner connectors dispensing whole" two kinds of process requirements.
3, high hardness after curing, but not brittle, with low elasticity and excellent waterproof performance, so that angle code and section ductile adhesive wall connections, which make up, various parts of the corner of the window to reduce deformation, cracking conditions an effective solution to the problem of leakage corner windows and doors.
4, one-component adhesive glue is completely cured Corner, Corner profiles cavity with an effective part of the shear strength of the adhesive can be achieved 10.3N/MM2, component Corner Shear strength can reach 18N/MM2, greatly enhanced strength corner of the window. That is, ordinary 60 series of profiles of the shear strength can exceed Cutaway.
5, colloidal slightly foaming during the curing process, expanded, forming metal to metal between the elastic pad, the effective transmission of forces weaken, play a shock, the cushion effect.
6, weather resistance, the ability of -40 ° C +80 ° C temperature variation, white or translucent gel, the gel will not play in the short yellow. Corner two-component glue in 230 ° C high temperature tolerance of 30 minutes, suitable for powder coating and other post-processing needs.
7, with special cleaning agent with a small amount of excess glue is easy to clean,Fixed Length plastic seals will not harm the surface profile of the coating and paint, environmental non-toxic.
The author believes that the current market a lot to promote the use of the German "Wei Shi" series Corner combination of gum and related ancillary products, aluminum doors and windows corner for structural reinforcement and sealed professionally designed to meet the requirements of various groups angle is aluminum door and window factory and the developers of the most sensible choice.
Gear pump mechanical seal shortcomings
1) is more complex, demanding for processing
2) Installation and replacement of cumbersome, requiring workers to have a certain level of technology
3) fortuitous accident occurred when handling more difficult.
Preparatory work before sealing the highest bid:
1) Check the mechanical seal models. Specifications to check whether the requirements of the design drawings, so parts (extraordinary is the sealing surface, secondary seal) for damage. Deformation. Cracks phenomenon, if defective and must be replaced or repaired
2) Check the mechanical seal with the size of the parts, roughness, parallel with the design requirements
3) Using a small spring mechanical vehicle seals should be checked small springs are the same length and rigidity
4) Check the host runout. Swing amount and around the degree of compliance with the technical requirements, the sealed chamber meets the installation scale, sealed cover and whether the axis perpendicular to the general requirements: Shaft runout is less than ± 0.5mm: axis swing amount (rotation ring seal point) is not greater than 0.06mm: maximum around the axis is not greater than 0.05mm: sealing cover gasket contact with the plane on the vertical centerline of the promise is not bad 0.03 ~ 0.05mm.
5) should be kept clean, the extraordinary is the rotating ring and the stationary ring seal surface and the secondary seal surface should be free of impurities. container seal Dust does not agree with unclean loosen the sealing surface.
6) does not agree with the percussion instruments sealing element. To prevent the seal is damaged.
2) Installation and replacement of cumbersome, requiring workers to have a certain level of technology
3) fortuitous accident occurred when handling more difficult.
Preparatory work before sealing the highest bid:
1) Check the mechanical seal models. Specifications to check whether the requirements of the design drawings, so parts (extraordinary is the sealing surface, secondary seal) for damage. Deformation. Cracks phenomenon, if defective and must be replaced or repaired
2) Check the mechanical seal with the size of the parts, roughness, parallel with the design requirements
3) Using a small spring mechanical vehicle seals should be checked small springs are the same length and rigidity
4) Check the host runout. Swing amount and around the degree of compliance with the technical requirements, the sealed chamber meets the installation scale, sealed cover and whether the axis perpendicular to the general requirements: Shaft runout is less than ± 0.5mm: axis swing amount (rotation ring seal point) is not greater than 0.06mm: maximum around the axis is not greater than 0.05mm: sealing cover gasket contact with the plane on the vertical centerline of the promise is not bad 0.03 ~ 0.05mm.
5) should be kept clean, the extraordinary is the rotating ring and the stationary ring seal surface and the secondary seal surface should be free of impurities. container seal Dust does not agree with unclean loosen the sealing surface.
6) does not agree with the percussion instruments sealing element. To prevent the seal is damaged.
2013年10月27日星期日
Experts discuss starter gel sealed lead-acid battery type font
"Start -type gel sealed lead acid battery technology Seminar " was held recently in Beijing , high security bolt seals State Department Counselor Xu Dingming , Deputy Director of Science and Technology Development Plan and other related departments Liu Jinlin leaders and experts attended the meeting.
According to the project responsible person Zhang Dianding introduction , development polluting silicone body battery , validated by the former State Science and Technology Commission as a national key new product plan and the Torch Program and get Guangxi Science and Technology Progress Award. Sealed lead-acid battery -starter colloidal silica sol is added to a water-soluble after formation within the cell, through specific charging method to achieve the electrolyte into the gel to improve the relative performance of the battery . The product testing by the state authorities , some indicators than the national standard .
State Department counselor Xu Dingming noted that the project is an energy storage device , storage device is a new national energy policy revolution important part , cable ties not from the energy conservation , energy security is inseparable from the region , the smart grid can not be separated . Experts say : starting gel sealed lead-acid battery type is mainly used in automobile starters , the technology can also be applied to areas such as energy storage , belonging to the new energy industry to reduce pollution of the environment , in line with national industrial policy, its technology has reached the leading domestic level .
According to the project responsible person Zhang Dianding introduction , development polluting silicone body battery , validated by the former State Science and Technology Commission as a national key new product plan and the Torch Program and get Guangxi Science and Technology Progress Award. Sealed lead-acid battery -starter colloidal silica sol is added to a water-soluble after formation within the cell, through specific charging method to achieve the electrolyte into the gel to improve the relative performance of the battery . The product testing by the state authorities , some indicators than the national standard .
State Department counselor Xu Dingming noted that the project is an energy storage device , storage device is a new national energy policy revolution important part , cable ties not from the energy conservation , energy security is inseparable from the region , the smart grid can not be separated . Experts say : starting gel sealed lead-acid battery type is mainly used in automobile starters , the technology can also be applied to areas such as energy storage , belonging to the new energy industry to reduce pollution of the environment , in line with national industrial policy, its technology has reached the leading domestic level .
New seals leak and cause analysis
Sometimes mechanical seal leakage , not due to leakage caused by face , but because ring, stationary ring seal or sleeve seal leak caused . For the following reasons :
Machine rubber seals leak
Actuating ring, stationary ring "O" type rubber seals, rubber finish is not enough because the hardness inappropriate , good elasticity , friction coefficient, geometry failure , heat resistance, corrosion resistance and other good reasons, often cause seal leakage .
Machine shaft seal ring in contact with leaking
When a sleeve repeated use in contact with ring seal and sleeve at the sleeve surface will have a rough grinding marks and spots , often caused by seal leakage . The main reasons are:
( 1) Since the rail car seals ring and the sleeve exists between the small amount of relative movement , or other hard abrasive grains embedded impurities into the softer seal . Produce a friction rub on the sleeve , and the sleeve surface without surface hardening treatment or processing of poor quality , resulting in wear and tear.
( 2 ) the result of friction rub , the metal surface passivation film sleeve damage present on the surface of the metal sleeve electrode potential difference , the formation of electrochemical corrosion. Also, because of the contact at the leak itself and in the micro crevice corrosion when they have the condition , therefore , the corrosion rate is higher . Furthermore , seal ring side in contact with the atmosphere , due to the presence of oxygen , more complex and harsh etching conditions , so wear marks and spots more obvious.
PTFE sealing ring group polytetramethylene used in the ring , due to the smaller coefficient of friction than the rubber , high finish , easy to move with the ring , thus , is better than the rubber seals . Rubber seals used in the stationary ring , due to good elasticity, low hardness, therefore , the reliability is better than the PTFE ring seal . Therefore, a reasonable choice of ring material is also very important, and we based on the specific circumstances of corrosion on the mechanical seal made the following adjustments: the media side stationary ring with Teflon rings or rubber ring temperature corrosion in the atmosphere quiet side always use rubber ring ring ; ring PTFE seals are generally used , the effect is more ideal .
Bushings eliminate fretting , except try to use the sleeve surface hardness, good corrosion resistance, and maternal affinity, high surface finish of better spraying spraying materials and processes , but also pay attention when installing bushings wear, timely replacement of bushings, new security seals, in many ways to ensure sealing reliability.
Machine rubber seals leak
Actuating ring, stationary ring "O" type rubber seals, rubber finish is not enough because the hardness inappropriate , good elasticity , friction coefficient, geometry failure , heat resistance, corrosion resistance and other good reasons, often cause seal leakage .
Machine shaft seal ring in contact with leaking
When a sleeve repeated use in contact with ring seal and sleeve at the sleeve surface will have a rough grinding marks and spots , often caused by seal leakage . The main reasons are:
( 1) Since the rail car seals ring and the sleeve exists between the small amount of relative movement , or other hard abrasive grains embedded impurities into the softer seal . Produce a friction rub on the sleeve , and the sleeve surface without surface hardening treatment or processing of poor quality , resulting in wear and tear.
( 2 ) the result of friction rub , the metal surface passivation film sleeve damage present on the surface of the metal sleeve electrode potential difference , the formation of electrochemical corrosion. Also, because of the contact at the leak itself and in the micro crevice corrosion when they have the condition , therefore , the corrosion rate is higher . Furthermore , seal ring side in contact with the atmosphere , due to the presence of oxygen , more complex and harsh etching conditions , so wear marks and spots more obvious.
PTFE sealing ring group polytetramethylene used in the ring , due to the smaller coefficient of friction than the rubber , high finish , easy to move with the ring , thus , is better than the rubber seals . Rubber seals used in the stationary ring , due to good elasticity, low hardness, therefore , the reliability is better than the PTFE ring seal . Therefore, a reasonable choice of ring material is also very important, and we based on the specific circumstances of corrosion on the mechanical seal made the following adjustments: the media side stationary ring with Teflon rings or rubber ring temperature corrosion in the atmosphere quiet side always use rubber ring ring ; ring PTFE seals are generally used , the effect is more ideal .
Bushings eliminate fretting , except try to use the sleeve surface hardness, good corrosion resistance, and maternal affinity, high surface finish of better spraying spraying materials and processes , but also pay attention when installing bushings wear, timely replacement of bushings, new security seals, in many ways to ensure sealing reliability.
2013年10月26日星期六
Pump mechanical seal failure analysis
Mechanical seal means two sealing elements perpendicular to the axis of the smooth and flat surface bonded to each other and constituting the sealing relative to the rotation of the device. It usually consists of stationary ring , ring , spring loading device ( including the thrust ring , spring , spring seat , fixing screws , drive pin ) , the auxiliary ring ( ring ring seals and static seals ) and other components . Anti-rotation pin fixed to the gland to prevent static ring rotation.
From a structural point of view, the mechanical seal is easy to leak mainly axial seal , change the seal easily leaks . Because of mechanical seal has sealing performance , reliable, leak less , long life, low power consumption , does not require frequent maintenance, etc. , and can meet the production automation and high temperature , releasable cable ties low temperature, high pressure, high vacuum , high speed, a variety of explosive , corrosive and corrosive media sealing requirements , thus to obtain more rapidly than other sealing the development and promotion of more and more alternative packing seal and other seals .
Early failure of the mechanical seal now common phenomenon , causes and remedies described below:
A new face early wear and tear causes and solutions
Mechanical seal face common cause early wear and tear are the following .
1.1 motorized ring and stationary ring material selection is appropriate
By the ring and static friction ring is composed of the most important parts of the mechanical seal . Seal life and work quality ( leakage index ) are and it has a direct relationship .
Mechanical seal friction material according to the nature of the pump working medium , working pressure , temperature, rotation speed and other factors to choose, especially for old products on mechanical seal or packing seal retrofit transformation of the original mechanical seals , mechanical seals rational choice material is very important. When the mechanical seal in a corrosive medium, it is subjected to a chemical and galvanic corrosion , particularly in the friction surface , the corrosion rate is great , it is just because the end surface of the corrosion product is generated ( to reduce the corrosion rate ) was friction cause damage .bolt security seals This generated by corrosion-resistant surface to rub off , periodic cycles of more than, often referred to abrasion phenomenon . The abrasion rate of about no friction surface corrosion rate of 10 to 50 times . Therefore, the friction should choose both corrosion resistance and good wear resistance of materials . Generally , graphite impregnated with phenolic resin acid not alkali , acid and also alkali impregnated furan resin , epoxy resin impregnated alkali resistance , impregnated with PTFE resin and ceramic capability corrosive media .
From a structural point of view, the mechanical seal is easy to leak mainly axial seal , change the seal easily leaks . Because of mechanical seal has sealing performance , reliable, leak less , long life, low power consumption , does not require frequent maintenance, etc. , and can meet the production automation and high temperature , releasable cable ties low temperature, high pressure, high vacuum , high speed, a variety of explosive , corrosive and corrosive media sealing requirements , thus to obtain more rapidly than other sealing the development and promotion of more and more alternative packing seal and other seals .
Early failure of the mechanical seal now common phenomenon , causes and remedies described below:
A new face early wear and tear causes and solutions
Mechanical seal face common cause early wear and tear are the following .
1.1 motorized ring and stationary ring material selection is appropriate
By the ring and static friction ring is composed of the most important parts of the mechanical seal . Seal life and work quality ( leakage index ) are and it has a direct relationship .
Mechanical seal friction material according to the nature of the pump working medium , working pressure , temperature, rotation speed and other factors to choose, especially for old products on mechanical seal or packing seal retrofit transformation of the original mechanical seals , mechanical seals rational choice material is very important. When the mechanical seal in a corrosive medium, it is subjected to a chemical and galvanic corrosion , particularly in the friction surface , the corrosion rate is great , it is just because the end surface of the corrosion product is generated ( to reduce the corrosion rate ) was friction cause damage .bolt security seals This generated by corrosion-resistant surface to rub off , periodic cycles of more than, often referred to abrasion phenomenon . The abrasion rate of about no friction surface corrosion rate of 10 to 50 times . Therefore, the friction should choose both corrosion resistance and good wear resistance of materials . Generally , graphite impregnated with phenolic resin acid not alkali , acid and also alkali impregnated furan resin , epoxy resin impregnated alkali resistance , impregnated with PTFE resin and ceramic capability corrosive media .
New seal ring fragmentation causes and prevention measures
mechanical security seals seal ring fragmentation is a common phenomenon of early failure . Graphite stationary ring main is broken off , ceramic , tungsten carbide ring is mainly Seals cracks and deformation . Graphite ring broken off , a serious leak sealing , sealing medium pressure greater than the pressure can not be guaranteed . Although ring crack , causing leakage increased, but in most cases, but also to maintain operation . Resulting graphite ring broken off for many reasons , mainly the following .
( 1 ) Rubber seals or PTFE V-ring and graphite ring and stationary ring seat fit too tight , graphite by squeezing , under the dynamic fragmentation .
( 2 ) Install the seal chamber and pump in shock when heavy or pump seal chamber heavily skewed .
( 3 ) the swing axis and the string exceeds the specified value.
( 4 ) seal water interruption friction dry friction, high temperature , sealing ring thermal cracking , but suddenly sent to seal water , violent contraction of the seal ring fragmentation .
Ring crack main reasons are:
( 1 ) carbide ring , there is a greater stress on moving ring operation, in force , under the combined effects of internal forces cracks . These cracks are diverging radially dense fine cracks.
( 2 ) Temperature: non-metallic materials for the seal ring ( such as ceramic , WC), due to thermal conduction is not good , the ring is very uneven temperature distribution , even in normal conditions, the temperature may reach several Baidu , the temperature difference due to the presence and, thus, thermal stress caused by thermal deformation . When the thermal stress reaches a certain level , resulting in stress exceeds the ultimate strength of the material . At this time, the sealing ring on brittle materials tend to produce surface cracking , thereby enabling the sealing surface of the friction and wear and tear and failure. Due to thermal deformation of the sealing surface will fit clearance distortion, thus increasing the leakage .
Ring face with carbide , due to the thermal expansion coefficients of these materials are small , and the substrate materials, the thermal expansion coefficient difference between the larger ( stainless steel carbide thermal expansion coefficient than 3 to 4 times ) , so when the sealing temperature l exceeds a certain value , it will cause surfacing carbide seal ring deformation or cracks.
Solving dynamic and static bad fragmentation and deformation effective measures , in addition to strictly control the quality of spare parts processing , careful installation and maintenance , enhance operational management , the guarantee can be fully cable seals face lubrication and cooling are important measures. However, in practice, not any time to ensure adequate lubrication and cooling , seal water pressure fluctuations , disruption and misuse of workers , will cause the seal to lose sufficient lubrication and cooling.
( 1 ) Rubber seals or PTFE V-ring and graphite ring and stationary ring seat fit too tight , graphite by squeezing , under the dynamic fragmentation .
( 2 ) Install the seal chamber and pump in shock when heavy or pump seal chamber heavily skewed .
( 3 ) the swing axis and the string exceeds the specified value.
( 4 ) seal water interruption friction dry friction, high temperature , sealing ring thermal cracking , but suddenly sent to seal water , violent contraction of the seal ring fragmentation .
Ring crack main reasons are:
( 1 ) carbide ring , there is a greater stress on moving ring operation, in force , under the combined effects of internal forces cracks . These cracks are diverging radially dense fine cracks.
( 2 ) Temperature: non-metallic materials for the seal ring ( such as ceramic , WC), due to thermal conduction is not good , the ring is very uneven temperature distribution , even in normal conditions, the temperature may reach several Baidu , the temperature difference due to the presence and, thus, thermal stress caused by thermal deformation . When the thermal stress reaches a certain level , resulting in stress exceeds the ultimate strength of the material . At this time, the sealing ring on brittle materials tend to produce surface cracking , thereby enabling the sealing surface of the friction and wear and tear and failure. Due to thermal deformation of the sealing surface will fit clearance distortion, thus increasing the leakage .
Ring face with carbide , due to the thermal expansion coefficients of these materials are small , and the substrate materials, the thermal expansion coefficient difference between the larger ( stainless steel carbide thermal expansion coefficient than 3 to 4 times ) , so when the sealing temperature l exceeds a certain value , it will cause surfacing carbide seal ring deformation or cracks.
Solving dynamic and static bad fragmentation and deformation effective measures , in addition to strictly control the quality of spare parts processing , careful installation and maintenance , enhance operational management , the guarantee can be fully cable seals face lubrication and cooling are important measures. However, in practice, not any time to ensure adequate lubrication and cooling , seal water pressure fluctuations , disruption and misuse of workers , will cause the seal to lose sufficient lubrication and cooling.
2013年10月24日星期四
How to choose the right repair seals
Notice for users in the purchase of maintenance repair seals , most users will be according to the sample size and color to buy, this will only increase the difficulty of purchasing , but not necessarily be able to select the appropriate product. The following procedures are recommended to improve the accuracy of purchase seals :
1 the direction of movement - first determine the location of the sealing member movement direction , such reciprocating , rotary ,ss cable ties screw or fixed .
2 Sealed focus - such as deciding the point of activity in the inner diameter of the rod seal or activity point is at the outer diameter of the piston seal.
3 Temperature Class - Instructions for use machinery from the factory to inspect or assess the actual working environment temperature, determine the required use of materials . For a description of the temperature level of production users can refer to the following precautions .
4 pressure levels - from factory machinery access to the relevant data for use , or by observing the original seals and structural inference softness working pressure rating, a description of the relevant pressure level production users can refer to the following precautions .
5 size - most users will by used to buy old samples , but seals in use for some time, will be the temperature,colored cable ties pressure and wear and tear and other factors significantly affect its original size, press the select sample only as a reference , a better approach is to measure the location of the metal seal tank size , accuracy will be higher .
1 the direction of movement - first determine the location of the sealing member movement direction , such reciprocating , rotary ,ss cable ties screw or fixed .
2 Sealed focus - such as deciding the point of activity in the inner diameter of the rod seal or activity point is at the outer diameter of the piston seal.
3 Temperature Class - Instructions for use machinery from the factory to inspect or assess the actual working environment temperature, determine the required use of materials . For a description of the temperature level of production users can refer to the following precautions .
4 pressure levels - from factory machinery access to the relevant data for use , or by observing the original seals and structural inference softness working pressure rating, a description of the relevant pressure level production users can refer to the following precautions .
5 size - most users will by used to buy old samples , but seals in use for some time, will be the temperature,colored cable ties pressure and wear and tear and other factors significantly affect its original size, press the select sample only as a reference , a better approach is to measure the location of the metal seal tank size , accuracy will be higher .
The main characteristics of polysulfide sealant
Because liquid polysulfide polymer main chain containing -ss- bond , and is saturated , so the sealant made with unique properties : oil, water , solvent resistance to atmospheric aging , resistance to radiation , low temperature , good song , excellent air tightness . Can be used for construction projects , large reservoirs, diversion works , sewage treatment , bolt security seals roads, bridges , doors, windows and other joints , settlement is sealed.
l, adhesion : polysulfide sealant for cement , steel, glass, wood , natural stone , etc. have good adhesion. General building and water conservancy projects on the appropriate use of low modulus, high elongation polysulfide sealant , its bond strength ≥ 0.2Mpa, Elongation ≥ 300%.
2, the water resistance : polysulfide sealant for water, tap water, distilled water, the role of stability , compared to seawater ( salt ) the minimum change in weight .
3 , acid and alkaline able to: polysulfide sealant resistant to strong acids, alkalis . However, the dilute mineral acid, vehicle seals alkali and various salts , or stable .
4 , heat aging properties : polysulfide sealant heat aging performance very good, long-term in a 40 ℃ ~ 120 ℃ working conditions .
l, adhesion : polysulfide sealant for cement , steel, glass, wood , natural stone , etc. have good adhesion. General building and water conservancy projects on the appropriate use of low modulus, high elongation polysulfide sealant , its bond strength ≥ 0.2Mpa, Elongation ≥ 300%.
2, the water resistance : polysulfide sealant for water, tap water, distilled water, the role of stability , compared to seawater ( salt ) the minimum change in weight .
3 , acid and alkaline able to: polysulfide sealant resistant to strong acids, alkalis . However, the dilute mineral acid, vehicle seals alkali and various salts , or stable .
4 , heat aging properties : polysulfide sealant heat aging performance very good, long-term in a 40 ℃ ~ 120 ℃ working conditions .
2013年10月23日星期三
Selection of gasket
Widely used in the gasket pipes, pressure vessels and various body joint surface static seal . There are non-metallic gaskets gaskets , non-metallic gaskets and metal combination and metal gasket three categories. The commonly used materials are rubber, leather , asbestos nylon zip ties, cork , PTFE , steel, iron, copper and stainless steel .
Gasket leaks in three forms : the interface leakage, infiltration leaks and destructive leak. Where previously the two as the main form .
Gasket selection :
Gasket selection principle is that, for less demanding situations, can be empirically selected sub- city again when replaced. But for those demanding applications such as explosive, toxic and combustible gases and highly corrosive liquids equipment, reaction tank and pipeline systems, etc. , should be based on operating pressure , operating temperature, sealed.
Flange surface roughness . The surface roughness of the sealing flange great effect , especially when using non- flexible gasket , the sealing surface roughness is caused by leakage of a large value of the main. For example , turning the blade flange is a spiral line pattern , using the metal gasket , if the roughness is large, it can not block the knife profile gasket is formed of spiral grooves which , under pressure , the media will along this trench leaked . Soft gasket to the flange surface finish is required is much lower, this is because it is easily deformed , fixed length plastic strap seal to block the machining tool pattern, thereby preventing leakage. Right soft gasket and flange surface is too smooth detriment .
Gasket leaks in three forms : the interface leakage, infiltration leaks and destructive leak. Where previously the two as the main form .
Gasket selection :
Gasket selection principle is that, for less demanding situations, can be empirically selected sub- city again when replaced. But for those demanding applications such as explosive, toxic and combustible gases and highly corrosive liquids equipment, reaction tank and pipeline systems, etc. , should be based on operating pressure , operating temperature, sealed.
Flange surface roughness . The surface roughness of the sealing flange great effect , especially when using non- flexible gasket , the sealing surface roughness is caused by leakage of a large value of the main. For example , turning the blade flange is a spiral line pattern , using the metal gasket , if the roughness is large, it can not block the knife profile gasket is formed of spiral grooves which , under pressure , the media will along this trench leaked . Soft gasket to the flange surface finish is required is much lower, this is because it is easily deformed , fixed length plastic strap seal to block the machining tool pattern, thereby preventing leakage. Right soft gasket and flange surface is too smooth detriment .
Heat pump mechanical seal Precautions
Heat pump according to the conditions of use of the different installation of different forms of mechanical seals , such as the built-in single-ended flat horizontal and non- balanced ,high security cable seals double-end balanced and unbalanced type , externally mounted mechanical seals , etc. Therefore , according to the choice of seals in different forms, its using methods and precautions are also different, generally have the following specific conditions :
1, the general mechanical seal suitable for cleaning medium without suspended particles , on the newly installed piping system should be carefully cleaned reservoir together to prevent solid impurities into the mechanical seal faces .
2, in the crystallization medium using mechanical seals , attention should be cleaned regularly , before the restart after stopping to get crystal mechanical seal clean .
3 , the mechanical seal should be carefully disassemble , prohibited by hand cone, iron and other percussion . Demolition should be clear dirt.
4 , strict inspection ring and the stationary ring for face grinding , does not allow any minor scratches, Pengpo other defects.
5 , the right to adjust the amount of compression springs , making it an appropriate degree of tightness to avoid excessive wear or leakage.
6, there is an external mechanical seal flush , start should be preceded by open cavity filled with fluid sealing liquid is sealed ,adjustable length plastic seals stopping when the first stop the pump, close the seal flush fluid.
1, the general mechanical seal suitable for cleaning medium without suspended particles , on the newly installed piping system should be carefully cleaned reservoir together to prevent solid impurities into the mechanical seal faces .
2, in the crystallization medium using mechanical seals , attention should be cleaned regularly , before the restart after stopping to get crystal mechanical seal clean .
3 , the mechanical seal should be carefully disassemble , prohibited by hand cone, iron and other percussion . Demolition should be clear dirt.
4 , strict inspection ring and the stationary ring for face grinding , does not allow any minor scratches, Pengpo other defects.
5 , the right to adjust the amount of compression springs , making it an appropriate degree of tightness to avoid excessive wear or leakage.
6, there is an external mechanical seal flush , start should be preceded by open cavity filled with fluid sealing liquid is sealed ,adjustable length plastic seals stopping when the first stop the pump, close the seal flush fluid.
2013年10月22日星期二
Conical shaft for the mechanical seal of the swing
Shaft swings may occur depending on the maximum pump heads ( the bottom one ) fluorine resin bearing radial clearance . According to the manufacturer 's standard , 9LDTN type condensate pump bearings allow maximum use of fluorine resin gap 0.4 mm, taking into account the fluorine resin bearing wear will not damage after mechanical seal , based on past experience overhaul , whichever heads fluorine resin bearing radial clearance to 2 mm. Principles calculations based on similar triangles , the mechanical seal shaft runout limit value of 0.24 mm, and then consider rolling under its own motor radial clearance is set to 0.1mm ( for 6226 bearing is damaged in terms of the gap ) , then mechanical shaft seals can get maximum runout of 0.34 mm. The selected mechanical seal allows runout of 0.5 ~ 0.7 mm, it will not damage the shaft for mechanical seal conical swing .
Transformation is due to the choice of cartridge single mechanical seal , installation is relatively simple and does not require any transformation of the pump , mechanical seal less work . However, in the transformation process involves the following considerations :
a) Check the condensate pump original packing sleeve outer periphery of ovality , elliptical too large to be replaced. Because mechanical seal sleeve must set this sleeve , with the Department by its O-ring indicative seal, sleeve oval spend much effect on the O-ring and sleeve contacts , causing leaks here .
b) packing sleeve and the shaft seal must be reliable without leakage, if packing between the sleeve and the shaft seal leakage , condensation will also affect water quality and vacuum unit .
c) the original packing chamber condensate pump outer face flat on the lathe processing needs . In order to ensure the mechanical seal stationary ring gland with a combination of good surface contact , it is best to fill up the cavity outer face flange portion for turning .
d) Install the mechanical seal , in a still sealed position using a good quality sealant to prevent leakage.
e) mechanical seal is in place, the pump and the motor must be in good and installed on the coupling after a fixed stationary ring and ring gland , and finally will be positioned to take the card to open . Otherwise , couplings and joints for adjusting the pendulum will cause partial radial and axial elevation will not only affect the mechanical seal static ring sealing surface contact , but also changes the mechanical seal tight static ring contact force, contact tightening force burned mechanical adjustable length seal over the General Assembly .
f) mechanical seal return pipe must be connected back to the pump inlet . Because the upper guide bearing a relief bore seal leakage , it serves to ensure the mechanical seal chamber pressure of not more than 490 kPa in effect, while the return pipe connected to a lower pressure , they may form a flow in order to promptly the movement of the mechanical seal sealing surface due to friction heat away .
Transformation is due to the choice of cartridge single mechanical seal , installation is relatively simple and does not require any transformation of the pump , mechanical seal less work . However, in the transformation process involves the following considerations :
a) Check the condensate pump original packing sleeve outer periphery of ovality , elliptical too large to be replaced. Because mechanical seal sleeve must set this sleeve , with the Department by its O-ring indicative seal, sleeve oval spend much effect on the O-ring and sleeve contacts , causing leaks here .
b) packing sleeve and the shaft seal must be reliable without leakage, if packing between the sleeve and the shaft seal leakage , condensation will also affect water quality and vacuum unit .
c) the original packing chamber condensate pump outer face flat on the lathe processing needs . In order to ensure the mechanical seal stationary ring gland with a combination of good surface contact , it is best to fill up the cavity outer face flange portion for turning .
d) Install the mechanical seal , in a still sealed position using a good quality sealant to prevent leakage.
e) mechanical seal is in place, the pump and the motor must be in good and installed on the coupling after a fixed stationary ring and ring gland , and finally will be positioned to take the card to open . Otherwise , couplings and joints for adjusting the pendulum will cause partial radial and axial elevation will not only affect the mechanical seal static ring sealing surface contact , but also changes the mechanical seal tight static ring contact force, contact tightening force burned mechanical adjustable length seal over the General Assembly .
f) mechanical seal return pipe must be connected back to the pump inlet . Because the upper guide bearing a relief bore seal leakage , it serves to ensure the mechanical seal chamber pressure of not more than 490 kPa in effect, while the return pipe connected to a lower pressure , they may form a flow in order to promptly the movement of the mechanical seal sealing surface due to friction heat away .
Measures to eliminate shaft deflection is too large
This phenomenon exists mostly horizontal multistage centrifugal pump , in the design of the following measures:
( A ) to reduce the distance between the ends of the bearing . Pump impeller stages not too much higher in the pump total head case , try to improve each impeller head, reducing progression .
( 2 ) increasing the diameter of the shaft . In the design of the shaft diameter , do not simply transfer power only to consider the size , and to consider the mechanical seal,tamper evident tape shaft deflection , starting methods and related inertia load , radial force and other factors. Many designers do not fully understand it.
( 3) improve the level of the shaft material .
( 4 ) shaft before installation on the shaft deflection test to be checked .
4 increase in auxiliary flushing system
When conditions permit , try to flush the system design assistance . General requirements for flushing pressure is higher than the seal chamber pressure 0.107 ~ 0.11 MPa, if the transmission medium is easily vaporized , the vapor pressure should be higher than 0.1175 ~ 0.12 MPa. Seal chamber pressure pump according to the structure of each type, and other factors to calculate the system pressure . Seal chamber pressure is high or when the pressure is almost close to the seal using the highest limit, also cited by the liquid seal chamber to the low pressure area , so that the liquid flow to seal away frictional heat . Recommended flushing volume as shown in Table 1 .
Pump mechanical seal table
According to the operating conditions of each pump , a reasonable allocation of piping and accessories. Such as coolers, plate , filters , valves, flow indicators , pressure gauge and temperature. Actually seal the reliability and life depends largely on the nylon cable tie support system configuration.
( A ) to reduce the distance between the ends of the bearing . Pump impeller stages not too much higher in the pump total head case , try to improve each impeller head, reducing progression .
( 2 ) increasing the diameter of the shaft . In the design of the shaft diameter , do not simply transfer power only to consider the size , and to consider the mechanical seal,tamper evident tape shaft deflection , starting methods and related inertia load , radial force and other factors. Many designers do not fully understand it.
( 3) improve the level of the shaft material .
( 4 ) shaft before installation on the shaft deflection test to be checked .
4 increase in auxiliary flushing system
When conditions permit , try to flush the system design assistance . General requirements for flushing pressure is higher than the seal chamber pressure 0.107 ~ 0.11 MPa, if the transmission medium is easily vaporized , the vapor pressure should be higher than 0.1175 ~ 0.12 MPa. Seal chamber pressure pump according to the structure of each type, and other factors to calculate the system pressure . Seal chamber pressure is high or when the pressure is almost close to the seal using the highest limit, also cited by the liquid seal chamber to the low pressure area , so that the liquid flow to seal away frictional heat . Recommended flushing volume as shown in Table 1 .
Pump mechanical seal table
According to the operating conditions of each pump , a reasonable allocation of piping and accessories. Such as coolers, plate , filters , valves, flow indicators , pressure gauge and temperature. Actually seal the reliability and life depends largely on the nylon cable tie support system configuration.
2013年10月11日星期五
Cycloid gear pump industry applications extended
Because nothing like cycloid gear involute gears meshing in the center distance separability , tooth profile curve equation is complex and engaging ordinary cycloid gear pump is a multi- point contact . Gang Here, cycloid gear machining high precision , small processing errors might prevent the assembly, or uneven loads .security tie Prior to the 1980s of last century by means of design calculations and processing technical limitations , cycloid gear pump application subject to certain restrictions. With the increased level of processing technology , especially the development of numerical control technology , cycloid gear machining accuracy gradually improved , the cost becomes lower , cycloid pump renewed attention .
Its application range with gradually expanded from general industrial extended to the field of micro-mechanical hydraulic systems and bio- engineering . With more teeth difference cycloid gear pump and the emergence of modern design and manufacturing technology development , research and cycloid gear pump by domestic and foreign scholars and producers attention. Recently, there are many foreign companies producing such a gear pump . It is understood that a large number of imports from abroad, air compressors, chillers, oxygen compressors, expanders , and a large number of chemical raw material conveyors often appear on the cycloid gear pump , especially in the chemical industry for delivering high-viscosity liquids on the device .trailer seals China also has many companies began producing teeth difference cycloid pump , but all in imitation of similar products abroad , mainly in order to meet the need for equipment maintenance .
Its application range with gradually expanded from general industrial extended to the field of micro-mechanical hydraulic systems and bio- engineering . With more teeth difference cycloid gear pump and the emergence of modern design and manufacturing technology development , research and cycloid gear pump by domestic and foreign scholars and producers attention. Recently, there are many foreign companies producing such a gear pump . It is understood that a large number of imports from abroad, air compressors, chillers, oxygen compressors, expanders , and a large number of chemical raw material conveyors often appear on the cycloid gear pump , especially in the chemical industry for delivering high-viscosity liquids on the device .trailer seals China also has many companies began producing teeth difference cycloid pump , but all in imitation of similar products abroad , mainly in order to meet the need for equipment maintenance .
Gear pump hydraulic system development
In order to adapt hydraulic system is toward fast response , small size, low noise direction, gear pumps in addition to actively take measures to maintain its low-pressure dosing system , lubrication system dominance , but still need the following directions:
( 1 ) low flow pulsation : flow pulsation will cause pressure fluctuations , causing the system to generate vibration and noise, which is associated with the requirements of modern hydraulic systems are inconsistent . Reduce flow pulsation method , in addition to the previously described measures, Saikawa complex multi- gear pump is a trend.
( 2 ) high-voltage technology : higher pressure is required by the system , but also gear pumps and piston pumps, vane pumps competition must be addressed . The high pressure gear pump of the work has made great progress , but by its own structural limitations , in order to further improve the working pressure is very difficult to be developed a new structure of the gear pump . In this regard, by a plurality of composite gear pump gear will have a great advantage, the country has many researchers has conducted some research, and achieved remarkable results pull tight plastic seals.
( 3 ) Low noise: abroad have long been "quiet" pump said. As people's awareness of environmental protection , the gear pump noise requirements have become more stringent. Gear pump noise is mainly composed of two parts , part of the process of meshing gear mechanical noise generated in the other part of the trapped oil hydraulic pressure generated by the impact of noise. The former gear precision machining and installation , while the latter mainly depends on the thoroughness of the pump unloading . For external gear pump , to achieve complete unloading is very difficult, thus further reducing pump noise subject to certain restrictions . In this regard, due to internal gear pump has a smooth , non- trapped oil phenomenon , low noise characteristics and attracted universal attention , especially linear conjugate tooth profile of the internal gear pump because of its smooth operation, low noise, and much favor , is becoming the focus of research .
( 4 ) Variable Displacement: gear pump displacement can not be adjusted , limiting its scope to use the same . In order to change the gear pump displacement , domestic and foreign scholars have done a lot of research work, and made a lot of research results. For variable displacement gear pump has a lot of aspects of the patent , but really very little can be converted into products . Balanced compound gear internal gear pump can be adjusted by changing the speed of the pump displacement meters , but the specific methods and structures to be studied further tamper seal.
( 5 ) Large displacement : For some systems require fast moving rice , said large displacement is required. But conventional gear pump displacement increased by many factors. This regard , balanced compound gear pump has significant advantages , such as a table three composite idler gear pump displacement equivalent to 6 units with a single pump displacement dimensions .
( 1 ) low flow pulsation : flow pulsation will cause pressure fluctuations , causing the system to generate vibration and noise, which is associated with the requirements of modern hydraulic systems are inconsistent . Reduce flow pulsation method , in addition to the previously described measures, Saikawa complex multi- gear pump is a trend.
( 2 ) high-voltage technology : higher pressure is required by the system , but also gear pumps and piston pumps, vane pumps competition must be addressed . The high pressure gear pump of the work has made great progress , but by its own structural limitations , in order to further improve the working pressure is very difficult to be developed a new structure of the gear pump . In this regard, by a plurality of composite gear pump gear will have a great advantage, the country has many researchers has conducted some research, and achieved remarkable results pull tight plastic seals.
( 3 ) Low noise: abroad have long been "quiet" pump said. As people's awareness of environmental protection , the gear pump noise requirements have become more stringent. Gear pump noise is mainly composed of two parts , part of the process of meshing gear mechanical noise generated in the other part of the trapped oil hydraulic pressure generated by the impact of noise. The former gear precision machining and installation , while the latter mainly depends on the thoroughness of the pump unloading . For external gear pump , to achieve complete unloading is very difficult, thus further reducing pump noise subject to certain restrictions . In this regard, due to internal gear pump has a smooth , non- trapped oil phenomenon , low noise characteristics and attracted universal attention , especially linear conjugate tooth profile of the internal gear pump because of its smooth operation, low noise, and much favor , is becoming the focus of research .
( 4 ) Variable Displacement: gear pump displacement can not be adjusted , limiting its scope to use the same . In order to change the gear pump displacement , domestic and foreign scholars have done a lot of research work, and made a lot of research results. For variable displacement gear pump has a lot of aspects of the patent , but really very little can be converted into products . Balanced compound gear internal gear pump can be adjusted by changing the speed of the pump displacement meters , but the specific methods and structures to be studied further tamper seal.
( 5 ) Large displacement : For some systems require fast moving rice , said large displacement is required. But conventional gear pump displacement increased by many factors. This regard , balanced compound gear pump has significant advantages , such as a table three composite idler gear pump displacement equivalent to 6 units with a single pump displacement dimensions .
2013年10月9日星期三
Wear of the pump bearings and seals resistant to solutions
( A ) problem : support bearing severe wear . Try a number of different plant materials, such as carbon , graphite, Teflon ® material with fillers , trying to find a suitable solution to the problem of wear and misalignment , all materials 2-3 months to be scrapped . Wherein the polytetrafluoroethylene material products due to wear so that the shaft wear, have a great leak , causing mechanical seal failure.
Workaround: polyimide carbon fiber composite materials instead of the original use of a filler PTFE bearings.
Results: polyimide carbon fiber composite material support bearings installed, has been successfully operating for more than 13 months , after using the first eight months , the central part of the agitator is removed temporarily use other equipment , then , the staff detected stirrer bearings, found on each side leakage rate is less than 0.005 per inch , then the average failure interval time increased by 300% to 400%.
(B ) the problem : the axis deviation caused by high vibration and shorten the life of the mechanical security seals, while generating the noise .
Workaround: polyimide carbon fiber composite material with stainless steel impeller mouth ring pump housing orifice ring ; using our materials throat bushings instead of the original graphite bushings.
Result: reduced vibration amplitude , thus extending the service life of the seal and bearing life , and enhance the free operation of the pump . Many pumps are in use as a filler in packing , packing main role is to prevent leaks, but also play a role in the bearing , stable axis . At present, many pumps have packing to mechanical seals, mechanical seals with the changes did not affect the bearing , while the axis deviation ( high vibration and associated impacts ) has become a problem .
Polyimide carbon fiber composite materials to improve pump , successfully resolved the customer's problem , the following main points:
A ) polyimide carbon fiber composite material is a non- metal wear , do not bite material . This allows the running clearance out ( API provides only half the interstitial metal material ), the smaller the gap can stabilize shaft bush , the smaller the gap can further limit the leakage orifice ring and leak rate.
2 ) Polyimide carbon fiber composite material is a high strength , high performance thermoplastic material .pull tight seal It is easy to injection molding, can absorb vibration and shock , while the metal is being replaced will cause vibration and shaft wear .
Parts : Equipped with a removable Teflon seal and bearing sleeve
Workaround: polyimide carbon fiber composite materials instead of the original use of a filler PTFE bearings.
Results: polyimide carbon fiber composite material support bearings installed, has been successfully operating for more than 13 months , after using the first eight months , the central part of the agitator is removed temporarily use other equipment , then , the staff detected stirrer bearings, found on each side leakage rate is less than 0.005 per inch , then the average failure interval time increased by 300% to 400%.
(B ) the problem : the axis deviation caused by high vibration and shorten the life of the mechanical security seals, while generating the noise .
Workaround: polyimide carbon fiber composite material with stainless steel impeller mouth ring pump housing orifice ring ; using our materials throat bushings instead of the original graphite bushings.
Result: reduced vibration amplitude , thus extending the service life of the seal and bearing life , and enhance the free operation of the pump . Many pumps are in use as a filler in packing , packing main role is to prevent leaks, but also play a role in the bearing , stable axis . At present, many pumps have packing to mechanical seals, mechanical seals with the changes did not affect the bearing , while the axis deviation ( high vibration and associated impacts ) has become a problem .
Polyimide carbon fiber composite materials to improve pump , successfully resolved the customer's problem , the following main points:
A ) polyimide carbon fiber composite material is a non- metal wear , do not bite material . This allows the running clearance out ( API provides only half the interstitial metal material ), the smaller the gap can stabilize shaft bush , the smaller the gap can further limit the leakage orifice ring and leak rate.
2 ) Polyimide carbon fiber composite material is a high strength , high performance thermoplastic material .pull tight seal It is easy to injection molding, can absorb vibration and shock , while the metal is being replaced will cause vibration and shaft wear .
Parts : Equipped with a removable Teflon seal and bearing sleeve
Characteristics of Compound Gear Pump
A ) compound gear pump flow characteristics ;
2 ) Compound Gear Pump Optimization Method ;
3 ) radial force balance methods and measures .seal cable Compound gear pump flow characteristics of the parameters involved in the calculation more complicated calculation , must resort to computer-aided design methods to achieve.
( 6 ) helical gear pumps helical gear pump research study is currently the focus of attention of researchers in domestic issues , Ganxue Hui , Zhao Liang and so on helical gear pump flow characteristics , the leakage flow characteristics , flow pulsation characteristics a study of helical gear pump research has laid a theoretical foundation.
( 7 ) gear pump gear pump noise noise control technology is engaged by the flow pulsation and shock caused by the control flow pulsation and noise from the lower tooth profile to start asking the relative sliding velocity .
( 8 ) Method of a variable gear pump gear pump because the engagement of the gear pump flow characteristic adjustment has been a problem , only up to consider the structural solution , there is no effective solution.
( 9 ) means of high-pressure gear pump gear pump working pressure increase is a development direction of the gear pump , the pressure increase caused by the question :
( 1 ) bearing life is shortened, shortening the life of the pump :
( 2 ) pump leak intensifies, the volumetric efficiency decreases.
Produce these two issues fundamental reason lies in the role of the unbalanced gear radial hydraulic pressure ,padlock seal and the pressure is higher, the greater the radial hydraulic pressure .
( 10 ) gear pump life and its influencing factors . Meshing gear pump unbalanced radial force is affecting the life of the main factors gear pump . Hydrostatic bearings can be used , reducing the radial force methods to improve the life of the gear pump , while reducing the radial force of the most effective way is to use more complex gear pump gear .
2 ) Compound Gear Pump Optimization Method ;
3 ) radial force balance methods and measures .seal cable Compound gear pump flow characteristics of the parameters involved in the calculation more complicated calculation , must resort to computer-aided design methods to achieve.
( 6 ) helical gear pumps helical gear pump research study is currently the focus of attention of researchers in domestic issues , Ganxue Hui , Zhao Liang and so on helical gear pump flow characteristics , the leakage flow characteristics , flow pulsation characteristics a study of helical gear pump research has laid a theoretical foundation.
( 7 ) gear pump gear pump noise noise control technology is engaged by the flow pulsation and shock caused by the control flow pulsation and noise from the lower tooth profile to start asking the relative sliding velocity .
( 8 ) Method of a variable gear pump gear pump because the engagement of the gear pump flow characteristic adjustment has been a problem , only up to consider the structural solution , there is no effective solution.
( 9 ) means of high-pressure gear pump gear pump working pressure increase is a development direction of the gear pump , the pressure increase caused by the question :
( 1 ) bearing life is shortened, shortening the life of the pump :
( 2 ) pump leak intensifies, the volumetric efficiency decreases.
Produce these two issues fundamental reason lies in the role of the unbalanced gear radial hydraulic pressure ,padlock seal and the pressure is higher, the greater the radial hydraulic pressure .
( 10 ) gear pump life and its influencing factors . Meshing gear pump unbalanced radial force is affecting the life of the main factors gear pump . Hydrostatic bearings can be used , reducing the radial force methods to improve the life of the gear pump , while reducing the radial force of the most effective way is to use more complex gear pump gear .
2013年10月8日星期二
Beverage bottle child may drink into the container sealed proposal
News Playback frequency exposure safety issues bottled beverages
As temperatures gradually warming , bottled drinks ushered in the year of the sales season. At the same time , some information about the safety of bottled beverages reports but can often be seen .
Ms. Wang Hefei Parkson supermarket bought in Jasmine Tea Master of bottled beverages. Open only to find that the cap wall covered with black mold substances . After Ms. Wang found a manufacturer, factory explanation is " previously encountered such a problem may be caused by moisture on the supermarket warehouse ."
In recent years , with regard to beverage bottle moldy , breeding eggs , frequent reports of excessive bacteria . These problems involve many well-known brands , showing not the case. The brand is also more for such quality issues attributed to warehousing, transportation and other circulation . Well, we almost daily consumption of bottled drinks, they are not fully sealed bottle in the end it ? Please enter the living laboratory period , the facts to give you the answer.
Sample: 4 bottles of mineral water , label 1,2,3,4 , 1,2 for the same brand of mineral water, which is internally threaded cap double parallel lines, 3,4 for the same brand of mineral water , which internal thread for the screw cap double lines ; gentian violet
Experimental conditions: the fully sealed and then tighten unscrew bottle of mineral water upside down into the gentian violet solution
Experimental Target : gentian violet solution will soak into the inside of the cap
Experimental Procedure
1 The test samples 1,3 unscrew , pour a glass of water , then tighten. Open a bottle of drinking too mimic the situation .
2 gentian violet take about 5 ml was poured into water , the water level height is about 3 cm , can be completely off caps.
3 respectively 1,2 inverted water bottle into the gentian violet solution and let stand for 5 minutes . After removing the bottle with a paper towel and put up dry.
4 Take 3,4 mineral water bottles, repeat step 3.
7 Unscrew guinea pigs 3,4 . Among them, the whole of the 4th sealed bottle caps innermost colored spots appear below the threads 3 , on the outermost whorl coloring water droplets. The 4th bottle mouth with colored spots under the thread , the bottle at no obvious staining . And before the experiment was then tighten the screw to open the 3rd bottle , barrier seals staining slightly above the 4th bottle , the bottle at no obvious staining .
6 Unscrew guinea pigs 1,2 , which is the 2nd bottle sealed inside found no shading . And before the experiment was unscrew and tighten No. 1 bottle , the cap edge coloring inside of the case . Bottles at the bottle and bottle screw were no shading .
5 4 bottles of mineral water to be dried and observed . Bottle of mineral water bottle and cap of about 1 cm were staining .
The 4th bottle caps with colored water droplets inside
Experimental results : closed bottle of mineral water infiltration staining solution is still possible , but it will not penetrate the bottle at .
● Expert Interpretation
Secretary-General of the International Food Packaging Association , professor of environmental experts said threaded portion of beverage bottles only play the role of reinforcement , but not confined, " really play a role in the sealed bottle on a prominent cushion , tightening the cap while pressing close to the bottle, sealing function . "
Introduction, vendors can make through ultrasound and heat shrinkable plastic shrink technology , to enhance or replace the mold bottle seal. But for cost reasons , most companies will not use these technologies , while the domestic beverage bottle hygiene standards at a blank spiral also enable manufacturers failed to give sufficient attention.
Said that as the threaded mouth is not sealed ,security seals in the filling , warehousing, transportation and other aspects of secondary contamination may exist , it is recommended to drink bottled beverages , do not directly touch the bottle mouth . " The use of straw may still exist secondary pollution , advised consumers to pour the beverage in the container and then drink ."
As temperatures gradually warming , bottled drinks ushered in the year of the sales season. At the same time , some information about the safety of bottled beverages reports but can often be seen .
Ms. Wang Hefei Parkson supermarket bought in Jasmine Tea Master of bottled beverages. Open only to find that the cap wall covered with black mold substances . After Ms. Wang found a manufacturer, factory explanation is " previously encountered such a problem may be caused by moisture on the supermarket warehouse ."
In recent years , with regard to beverage bottle moldy , breeding eggs , frequent reports of excessive bacteria . These problems involve many well-known brands , showing not the case. The brand is also more for such quality issues attributed to warehousing, transportation and other circulation . Well, we almost daily consumption of bottled drinks, they are not fully sealed bottle in the end it ? Please enter the living laboratory period , the facts to give you the answer.
Sample: 4 bottles of mineral water , label 1,2,3,4 , 1,2 for the same brand of mineral water, which is internally threaded cap double parallel lines, 3,4 for the same brand of mineral water , which internal thread for the screw cap double lines ; gentian violet
Experimental conditions: the fully sealed and then tighten unscrew bottle of mineral water upside down into the gentian violet solution
Experimental Target : gentian violet solution will soak into the inside of the cap
Experimental Procedure
1 The test samples 1,3 unscrew , pour a glass of water , then tighten. Open a bottle of drinking too mimic the situation .
2 gentian violet take about 5 ml was poured into water , the water level height is about 3 cm , can be completely off caps.
3 respectively 1,2 inverted water bottle into the gentian violet solution and let stand for 5 minutes . After removing the bottle with a paper towel and put up dry.
4 Take 3,4 mineral water bottles, repeat step 3.
7 Unscrew guinea pigs 3,4 . Among them, the whole of the 4th sealed bottle caps innermost colored spots appear below the threads 3 , on the outermost whorl coloring water droplets. The 4th bottle mouth with colored spots under the thread , the bottle at no obvious staining . And before the experiment was then tighten the screw to open the 3rd bottle , barrier seals staining slightly above the 4th bottle , the bottle at no obvious staining .
6 Unscrew guinea pigs 1,2 , which is the 2nd bottle sealed inside found no shading . And before the experiment was unscrew and tighten No. 1 bottle , the cap edge coloring inside of the case . Bottles at the bottle and bottle screw were no shading .
5 4 bottles of mineral water to be dried and observed . Bottle of mineral water bottle and cap of about 1 cm were staining .
The 4th bottle caps with colored water droplets inside
Experimental results : closed bottle of mineral water infiltration staining solution is still possible , but it will not penetrate the bottle at .
● Expert Interpretation
Secretary-General of the International Food Packaging Association , professor of environmental experts said threaded portion of beverage bottles only play the role of reinforcement , but not confined, " really play a role in the sealed bottle on a prominent cushion , tightening the cap while pressing close to the bottle, sealing function . "
Introduction, vendors can make through ultrasound and heat shrinkable plastic shrink technology , to enhance or replace the mold bottle seal. But for cost reasons , most companies will not use these technologies , while the domestic beverage bottle hygiene standards at a blank spiral also enable manufacturers failed to give sufficient attention.
Said that as the threaded mouth is not sealed ,security seals in the filling , warehousing, transportation and other aspects of secondary contamination may exist , it is recommended to drink bottled beverages , do not directly touch the bottle mouth . " The use of straw may still exist secondary pollution , advised consumers to pour the beverage in the container and then drink ."
Thread sealing
Thread seal on the pump, there are two ways , one is threaded coupling gasket seal , one is filled with economy plus thread sealing , Both small diameter threaded connections for sealing applications . Threaded coupling gasket sealing gasket seals are , but only as provided threaded clamping force. In addition to the sealing effect of the gasket outside its performance . The roughness of the sealing surface relative to the threaded hole of the sealing effect of the geometric positional accuracy of great impact .rail car seals The gasket is tightened by a screw not only withstand the pressing force , the torque is also exposed , the spacer is deformed or damaged , so that when the gasket is non-metallic , generally apply only where the pressure is not high , if the spacer metal above apply pressure up to 30Mpa .
Pump plugs frequently used , is another form of thread sealing . Taking into account the manufacturing economy plugs , generally can not play alone with threaded seal, often with raw tape, sealant fillers for thread sealing gap . Its bearing capacity depends on thread manufacturing precision and material, with plugs and threaded hole with the form does not matter. Threaded holes with plugs either a " cone on cone" or " columns on the cone" , the seal has the same effect , but using different regions only.
China currently uses two forms of the same . Affect the sealing effect is a common cause when machining starting hole size is too large , so that the thread deformation short crest wider, resulting in the sealing surface decreases, when the seal leak after pressure rises ,security seal and even plugs pressed out . As filler medium to be sealed leak corrosion phenomena in the chemical industry pumps also have occurred, so the choice of filler is also one of the factors considered sealed .
Pump plugs frequently used , is another form of thread sealing . Taking into account the manufacturing economy plugs , generally can not play alone with threaded seal, often with raw tape, sealant fillers for thread sealing gap . Its bearing capacity depends on thread manufacturing precision and material, with plugs and threaded hole with the form does not matter. Threaded holes with plugs either a " cone on cone" or " columns on the cone" , the seal has the same effect , but using different regions only.
China currently uses two forms of the same . Affect the sealing effect is a common cause when machining starting hole size is too large , so that the thread deformation short crest wider, resulting in the sealing surface decreases, when the seal leak after pressure rises ,security seal and even plugs pressed out . As filler medium to be sealed leak corrosion phenomena in the chemical industry pumps also have occurred, so the choice of filler is also one of the factors considered sealed .
2013年10月7日星期一
Effective measures to exclude mechanical seal failure
There are many ways to troubleshooting , here are a few conventional methods , for reference.
1 , must be monitored when the pump is running mechanical seal flush water return temperature , normal operation at 40 ℃ ~ 50 ℃ is the best, when the alarm when the temperature exceeds 85 ℃ , when the temperature exceeds 90 ℃ trip .
2, to improve water quality. User pump, water pump and mechanical seal according to certain requirements implemented. Necessary, increase the coarse strainer for coarse filter , improving water quality to avoid failure .
3, for sealing the circulatory system to regularly washable , clean dirt and impurities, especially magnetic filters must be cleaned regularly switch to prevent dirt clogging the filter , resulting in seal cavity without water , resulting in ring crumble , resulting in failure .
4 , the pump operation manual before operating according to a certain operation , good exhaust , give seal cooling water before starting to pump . Conversely operation to seal the first start after the cooling water is likely to cause sealing ring movement burst.
5, the user of the minor repairs , replacement of the mechanical security seals should pay attention to clean all sealing parts, check friction surface , not a scratch , rubber O-ring is defective , really no problem before installing high-pressure boiler feed pump is in use use of a certain technical requirements , if not by the manufacturer 's technical requirements, the use of will malfunction.
1 , as in the pump is installed , you can not correctly installed according to the installation instructions , resulting in pump vibration, so that the pump mechanical seal face fit is not good enough , or the failure to open end , the seal leakage.
2 , the pump is running , or due to other reasons not fully exhaust the sealed chamber contains gas , operation pressure in the sealed chamber under the action of friction moment cause seal leakage prop open failure.
3 , the circulatory system is not clean or filter cleaning dirty , poor water quality , a foreign body, mud , etc., so that the friction surface wear can also result in serious trouble . Such as Anhui Huainan power plants, because the water is bad, bad cooling cycle , the heat transfer performance.
4 , in addition to the pump run time due to sudden pressure fluctuations , resulting in pulse pressure or frequent starts can make transmission parts , parts of the weak links in the anti-rotation cause damage , resulting in mechanical seal failure . So users using high pressure boiler feed pump when the first power plant process to resolve the correctness of the process is running to minimize pressure fluctuations , reducing the number of frequent start . In addition, the mechanical trailer seals to be considered in the design of wear -loop transfer torque to the driven shaft and the stationary ring from the stator is transmitted to the pump and starting force transmitted to the ring from the shaft drive on the strength calculation and choose to avoid generate more problems.
1 , must be monitored when the pump is running mechanical seal flush water return temperature , normal operation at 40 ℃ ~ 50 ℃ is the best, when the alarm when the temperature exceeds 85 ℃ , when the temperature exceeds 90 ℃ trip .
2, to improve water quality. User pump, water pump and mechanical seal according to certain requirements implemented. Necessary, increase the coarse strainer for coarse filter , improving water quality to avoid failure .
3, for sealing the circulatory system to regularly washable , clean dirt and impurities, especially magnetic filters must be cleaned regularly switch to prevent dirt clogging the filter , resulting in seal cavity without water , resulting in ring crumble , resulting in failure .
4 , the pump operation manual before operating according to a certain operation , good exhaust , give seal cooling water before starting to pump . Conversely operation to seal the first start after the cooling water is likely to cause sealing ring movement burst.
5, the user of the minor repairs , replacement of the mechanical security seals should pay attention to clean all sealing parts, check friction surface , not a scratch , rubber O-ring is defective , really no problem before installing high-pressure boiler feed pump is in use use of a certain technical requirements , if not by the manufacturer 's technical requirements, the use of will malfunction.
1 , as in the pump is installed , you can not correctly installed according to the installation instructions , resulting in pump vibration, so that the pump mechanical seal face fit is not good enough , or the failure to open end , the seal leakage.
2 , the pump is running , or due to other reasons not fully exhaust the sealed chamber contains gas , operation pressure in the sealed chamber under the action of friction moment cause seal leakage prop open failure.
3 , the circulatory system is not clean or filter cleaning dirty , poor water quality , a foreign body, mud , etc., so that the friction surface wear can also result in serious trouble . Such as Anhui Huainan power plants, because the water is bad, bad cooling cycle , the heat transfer performance.
4 , in addition to the pump run time due to sudden pressure fluctuations , resulting in pulse pressure or frequent starts can make transmission parts , parts of the weak links in the anti-rotation cause damage , resulting in mechanical seal failure . So users using high pressure boiler feed pump when the first power plant process to resolve the correctness of the process is running to minimize pressure fluctuations , reducing the number of frequent start . In addition, the mechanical trailer seals to be considered in the design of wear -loop transfer torque to the driven shaft and the stationary ring from the stator is transmitted to the pump and starting force transmitted to the ring from the shaft drive on the strength calculation and choose to avoid generate more problems.
Note polyurethane rubber seals made factors
① prepolymer synthesis temperature control , the temperature controlled at 75 ~ 82 ~ C, high performance will decrease the prepolymer synthesis , low will prolong the reaction time . MOCA when mixed with the prepolymer temperature at 90 ~ 110 ℃, high will reduce the hardness and strength of the product , the mixture will increase low spike Yan, is not conducive to casting operations. Curing temperature 120130 ~ C, high will , MOCA decomposition, is not conducive to cross -linking reaction , while the other side reactions increases , lower molding time will be extended . MOCA melting temperature can be controlled just melt into a liquid , can not continue to heat , or liquid MOCA become darker in color , decomposition , affecting crosslinking molding.
⑦ time control synthesis reaction 2h, intermittent vacuum for 2h , and then stored at room temperature and placed in secret . Prepolymer synthesis at 75 ~ C , the no more than 4 ~ h, more {j in high temperature (100 ~ C) for more than 2h, otherwise it will reduce product performance. Pouring should be completed within 1 ~ 2min nephew because prepolymer and MOCA stabilization period after mixing is very short, only 4 ~ 5min, stirring well takes time .
Molding and vulcanization time for the product to the shape and size , are generally between 15 ~ 30min , no less , to ensure the molded product . Sometimes encounter large production such as wheels , rollers , and its curing ( refer molded ) longer and need 2 ~ 3h OK .
③ degassed prepolymer is good or bad degassing casting polyurethane rubber plastic seal made key to success, the prepolymer synthesis on standing , 75 ℃ degassed under vacuum to remove most of the gas in the prepolymer ; prepolymer MOCA body and prior to mixing needs to be heated to a temperature 100 ~ 1 10 ℃ degassed. Meanwhile vacuum (- 0.095MPa) degassing 1Omin, then remove the air bubbles in the bottom stirring upper turn , pulls out the vacuum degassing 10rain, the prepolymer to exclude air bubbles in the clean, in order to cast products with the curing agent are mixed .
④ pressure is generally 14MPa pressure can be.
⑤ release agent Luoyang Liming Research Institute of Chemical 's 4031 production of polyurethane release agent, ester or ether -based polyurethane are preferred release agent. The 3rd month of Na- purpose lubrication , ordinary three calcium-based grease can also be used .
⑥ a set A is a prepolymer of NCO content of the setting , primarily based on degree of erosion products , mechanical and performance requirements on the performance of casting process . Average high hardness bigger ; smaller low hardness products mouth , mouth commonly used value of 3 % to 6% .
⑦ Select the main raw material selection , depending on whether water, heat water , depending ether except ammonia furans superior water resistance ester -based polyurethane .
⑦ mold manufacturing polyurethane container seals the mold and demanding , high structure is in addition to children with normal rubber mold requirements, should not be too small spout , structural casting, stripping and cleaning. In addition to the end of the structure , the cover , the middle block at least three blocks.
Casting shrinkage polyurethane rubber , is generally 1.30% to 1.35 %
⑦ time control synthesis reaction 2h, intermittent vacuum for 2h , and then stored at room temperature and placed in secret . Prepolymer synthesis at 75 ~ C , the no more than 4 ~ h, more {j in high temperature (100 ~ C) for more than 2h, otherwise it will reduce product performance. Pouring should be completed within 1 ~ 2min nephew because prepolymer and MOCA stabilization period after mixing is very short, only 4 ~ 5min, stirring well takes time .
Molding and vulcanization time for the product to the shape and size , are generally between 15 ~ 30min , no less , to ensure the molded product . Sometimes encounter large production such as wheels , rollers , and its curing ( refer molded ) longer and need 2 ~ 3h OK .
③ degassed prepolymer is good or bad degassing casting polyurethane rubber plastic seal made key to success, the prepolymer synthesis on standing , 75 ℃ degassed under vacuum to remove most of the gas in the prepolymer ; prepolymer MOCA body and prior to mixing needs to be heated to a temperature 100 ~ 1 10 ℃ degassed. Meanwhile vacuum (- 0.095MPa) degassing 1Omin, then remove the air bubbles in the bottom stirring upper turn , pulls out the vacuum degassing 10rain, the prepolymer to exclude air bubbles in the clean, in order to cast products with the curing agent are mixed .
④ pressure is generally 14MPa pressure can be.
⑤ release agent Luoyang Liming Research Institute of Chemical 's 4031 production of polyurethane release agent, ester or ether -based polyurethane are preferred release agent. The 3rd month of Na- purpose lubrication , ordinary three calcium-based grease can also be used .
⑥ a set A is a prepolymer of NCO content of the setting , primarily based on degree of erosion products , mechanical and performance requirements on the performance of casting process . Average high hardness bigger ; smaller low hardness products mouth , mouth commonly used value of 3 % to 6% .
⑦ Select the main raw material selection , depending on whether water, heat water , depending ether except ammonia furans superior water resistance ester -based polyurethane .
⑦ mold manufacturing polyurethane container seals the mold and demanding , high structure is in addition to children with normal rubber mold requirements, should not be too small spout , structural casting, stripping and cleaning. In addition to the end of the structure , the cover , the middle block at least three blocks.
Casting shrinkage polyurethane rubber , is generally 1.30% to 1.35 %
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