Various hydraulic valves hydraulic support life is very low, foreign ways and means to solve is to improve the system to improve filtering accuracy and the quality of emulsion, but with little success. This paper analyzes the stent valve sealing a development process, discusses the Sealing of the materials and the relationship between the sealing performance. Pointed out the sealing technology is to improve the service life of hydraulic valve hydraulic support in the key.
Hydraulic stent is in the supporting coal mining machine and, after a general overhaul in the underground can be used for five years, but the various hydraulic valves hydraulic support life is very low, a long 3 months, short only a few weeks, foreign ways and means to solve is to increase the filtration accuracy of the system and improve the quality of emulsion, but with little success. In the United Kingdom as an example of a hydraulic valve, although the machining accuracy and the entire hydraulic system have higher filtering accuracy, but the low life has been phased out in China.
One affecting the hydraulic valve sealing performance of the main factors
Sealing component damage factor is the working fluid in the main impurities. These impurities in a sealed between the grinding elements, so that valve leakage generated. Thus, raised abroad, the corresponding level of hydraulic components should be used accordingly the accuracy of filters. They think 5μM of the oil pump seal components, if we adopt the filtering accuracy 3/μM filter life than 10-fold increase in use of 10μM.
However, with the hydraulic valve stent, the working environment is very bad. In the coal face, tubing total length of more than 1000 meters, the joint socket up to more than 4000, and liquid tank without a special dust-proof facilities. Emulsion in a large number of floating impurities, Bottom and the valve chamber in the column, leaving more coal, rock grains, and iron filings. Into the liquid valve core and valve seat, due to turn off more frequently, the liquid flow rate high, sealing will soon expire. Practice has proved that reduction of hydraulic system fluid contamination of impurities, it is very difficult, it was once envisaged in emulsion pump high-pressure filter, while a small increase in the entrance of each stent filter. But in its work soon be blocked to form a stop.
On the other hand, with the hydraulic support technology development. The use of the valve performance and valve life put forward higher requirements. At present, when equipped with a 120 mesh filter and magnetic filtration devices under the conditions being tested through the valve with the emulsion of total traffic and the number of valves open and close to a metering valve life. But in fact underground room type test and the actual results of the work varies widely. Today, many countries in the form of experiments, an increase of anti-pollution requirements, or in emulsion of coal mixed with the appropriate, either by adding mechanical impurities.
To this end, the use of novel, anti-pollution ability, and suitable working conditions underground seal pair.
2, hydraulic valve seal materials, the history and current situation
Valve core and valve seat contact surface leakage, work the liquid molecules to squeeze into the results. Affect the sealing effect is mainly due to valve core and valve seat contact is better than pressure, roughness, and pressure. When the valve core and valve seat of the joints in order to compress P force, work force to squeeze into the liquid molecules to F, sealing materials, will produce elastic deformation. If the seal resistance greater than the vice president of molecular repulsion, then sealed and effective, otherwise it will form a leak.
Early hydraulic support, there are no other seal between the motion pairs measure is direct contact with metal seal, which called for sealing engagement plane Vice-match, with a high machining accuracy, or to increase the binding force of seal pair, so that contact with the surface plastic deformation, plug the leak channel. ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve Three way ball valve V Type Ball Valve
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