Pressure is limited by collars fitted. If a working pressure cannot be attained, remove some collars. One collar is equivalent to 10 MPa (1450 PSI).
If the internal volume of the vent line is too large, chattering is likely to occur.
The main factor of the damage of the sealing element is the impurity in the working fluid. These impurities grinding between the sealing element , so that the hydraulic cylinder pressure relief valve leakage.As a result, it has been proposed that the corresponding grade of hydraulic components should be used in the corresponding precision filter. If the filter accuracy of 5M oil pump sealing element is 3 / M filter, life can be 10 times higher than the use of 10 M.
But the working environment of the hydraulic support hydraulic pump pressure relief valve is very poor. In coal mining, tubing length of 1000 meters, up to more than 4000 joint socket, tank without special dust-proof facilities. A large number of floating impurities in the emulsion in coal, leaving more rock and iron tablets in the column bottom and the hydraulic pump pressure relief valve chamber. Valve core and valve seat due to the frequent opening and closing and high liquid flow rate, the seal will soon fail. Practice has proved that it is very difficult to reduce the pollution of the liquid in the hydraulic system. It has been assumed that the use of high pressure filter in the emulsion pump station, while set more small filters in the inlet of each bracket. But at work will soon be blocked, so as to form a stop.
On the other hand, with the development of the hydraulic support technology, the requirements for the hydraulic cylinder pressure relief valve performance and service became higher. At present, under the condition of 120 mesh filter and magnetic filter device, the life of the valve is measured by the total flow rate of the valve and the opening and closing times of the hydraulic pump pressure relief valve. But in fact, indoor and underground test results vary widely. Now many countries have increased the anti pollution requirements, some of which are mixed with the appropriate coal in the emulsion, some of which is to add mechanical impurities.