Hydraulic pneumatic valve sealing technology and data analysis

the service life of all kinds of hydraulic pneumatic valve in hydraulic support is very low, foreign way and solution is to improve the filtering precision of the system and improve the quality of the emulsion, but it is not big. In this paper, the development of the bracket of the pneumatic valve seal, seal materials are discussed and the relationship between the sealing performance. Points out the sealing technology is to improve the service life of hydraulic pneumatic valve in hydraulic support of the key.
hydraulic support is the supporting equipment in coal mining machinery, after overhaul in general can use five years, but the service life of all kinds of hydraulic pneumatic valve in hydraulic support is very low, long months, short only a few weeks, the way and solution is to increase system abroad filtering precision and improve the quality of the emulsion, but it is not big. In Britain, a hydraulic pneumatic valve as an example, although the machining accuracy and the whole hydraulic system filtration precision is high, but because of low service life, has been facing elimination in our country.
, the main factors influencing the hydraulic pneumatic valve sealing performance, packing element damage is the main factors of the impurity in the working fluid. These impurities grinding between the sealing element, make the pneumatic valve from leaking. Abroad, therefore, has put forward the corresponding grades of hydraulic components, should adopt the corresponding precision filter. They think mu M pump seal element, if the filtration precision filter for M/mu, life than the mu M times.
but hydraulic support with pneumatic valve, working environment is very bad. In the mining face, the total length of the tubing meters, joint pin up to multiple, tank no special dust-proof facilities. There are a large number of floating impurities in emulsion, and pneumatic valve chamber in the bottom of a column cylinder, leave more pulverized coal and rock grains and iron filings. In hydraulic and pneumatic pneumatic valve core seat, because open shutoff is frequent, high liquid velocity, seal failure soon. Proved less support liquid of hydraulic system pollution of impurities, it is very difficult, someone once envisaged in the emulsion pump station adopts high pressure filter, in each bracket inlet at the same time increase the small filter. But was quickly blocked in the work, form.
on the other hand, with the development of hydraulic support technology. The use of pneumatic valve performance and service life of the pneumatic valve higher requirements are put forward. At present, when a mesh filters and magnetic filter under the condition of use by the total capacity of the emulsion on pneumatic valve is tested and the number of pneumatic valve opening and closing, measured the service life of pneumatic valve. But in fact indoor type testing and downhole working results vary widely. Now many countries in the form of the experiment, increased the anti pollution for, have a plenty of mixed with appropriate coal powder in the emulsion, have a plenty of joining mechanical impurities.
to do this, you need to use the new, strong ability to resist pollution, is suitable for downhole working conditions of seal.
the history and status quo, hydraulic pneumatic valve sealing material, leakage, pneumatic valve core and pneumatic seat contact is the result of liquid molecules into work. Affect the sealing effect is the main reason of the pneumatic valve core and pneumatic seat contact pressure, roughness and differential pressure. When the pneumatic valve core and pneumatic seat junction plane with P compaction force, working liquid molecules to force into F, sealing material can produce elastic deformation. If the seal deputy resistance is greater than the molecular repulsive force, the sealing effective, otherwise will form the leak.
early hydraulic support, there is no other sealing measures between kinematic pair, is direct contact with the metal seal, requiring the seal contact surface, has high machining accuracy, otherwise must increase the adhesion strength of the seal, and make the contact surface to produce plastic deformation, plug leak path.