Abstract: in the hydraulic support various hydraulic valves service life is very low, foreign solutions and measures to improve the system is filtration precision and enhance the quality of emulsion, but had not. The paper analyzes the valve seal, discusses the development process of the material and the seal of the relationship between the sealing performance. Sealing technology is pointed out in the hydraulic support to improve the service life of hydraulic valves.
Hydraulic support's mining machinery and equipment, through the support in general use overhaul in five years, but the hydraulic support various hydraulic valves service life is very low, long, short 3 months of only a few weeks, foreign solutions and measures is to increase the filtration precision and improve the system of quality, but the outcome emulsion. With a British hydraulic valve, for example, although the machining accuracy and the hydraulic system are high precision, but for life in China, has been eliminated.
1 influence hydraulic valves sealing performance
Sealing element damage is the main factor of working liquid impurities. These impurities in sealing element, make valve between grinding leak. Therefore, the corresponding level of overseas have hydraulic components, should adopt appropriate precision filter. They may think of the pump seal components muon m, if the filtration precision for 3 / mu m filters, life is improved by 10 mu m 10 times.
But with valve hydraulic support environment is very bad, and work. In the mining face, more than 1,000 meters, total tubing connector socket as more than 4000, liquid tank no special dustproof facilities. There are a lot of emulsion floating impurities, the pillar crock bottom and valve chamber, have more coal, grain and iron. In the core and seat, due to open shutoff frequently, high velocity, liquid sealed will soon. Practice has proved reduce pollution of liquid stent hydraulic system impurities, it is difficult to imagine someone in the emulsion pump adopts high voltage filter, at the same time in each machine bracket inlet small filter. But in work quickly clogged, forming flow.
On the other hand, along with the development of hydraulic support technology. The use of valve performance and valve life put forward higher request. At present, with 120 mesh in the filter and magnetic filter device, the condition is tested through the valve with the blade and valve emulsion, open the valve to measurement. But actually indoor type test results of actual work with mine. Now many countries, in the form of increased resistance experiment, in the emulsion is contaminated with appropriate coal, have joined mechanical impurities.
Therefore, we need to use new and strong ability of pollution, suitable for underground work condition of seal.
2 hydraulic valve sealing materials of history and status
Valve spool and seat surface leakage, is working liquid molecular pushed results. Seal effect is the main reason of the valve spool and seat contact pressure, roughness and differential pressure. When the valve is the core and the joints with p seat, working pressure with liquid molecular impact force f, sealing material can produce elastic deformation. If the sealing vice-president, molecular repulsive force more effectively, otherwise it will seal leakage form.
Early hydraulic support, no other sealing between motion pair, is in direct contact with metal sealing, which requires seal contact surface, high machining accuracy, otherwise, must increase seal bonding, make contact surface plastic deformation, jams leak path.