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 .

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.

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 .

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 .

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

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 .

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 ."