Manifold block

Problems in the use of Manifold block pilot relief valve


There are some problems in the use of pilot relief valves, but many of the problems are attributed to the wear of the poppet spool, the blockage of the choke hole, and the length of the pipe between the remote pilot valve and the main pilot valve.


During the operation of pilot relief valve, the pilot valve’s poppet spool will wear due to moving back and forth on the seat, causing the spring chamber of the main valve to leak back to the oil tank. If the leakage is too large due to wear, sufficient control pressure above the annular edge of the main spool cannot be maintained, resulting in instability of the main valve and system pressure.

The use of pilot relief valve


Did not use a filter in the system of right protection under the condition of oil pollutants in May clog the throttle valve core, which means that at the top of the spring pressure not to valve core control cavity, when this happens, the main valve core will move once closed, no longer or shut down very slowly, because through the orifice pressure transmission is very difficult.


In some cases, the problem is the length of the connection between the main valve and the remote pilot valve. The further the remote pilot valve is removed from its main valve, the more opportunities there are for pressure pulsations, oil compressibility, and the main valve spring to interact with each other to generate excitation noise and excessive vibration. For this reason, it is generally recommended that the line length be kept to a minimum.


Relief valve adjustment


The pressure gauge should be installed near the oil outlet of the hydraulic pump or the valve body of the relief valve. The oil in the tank should reach its working temperature. Under this condition, the relief valve of the system can be accurately adjusted.


The pressure of the relief valve is set high enough so that no flow passes through the valve. The pressure gauge will indicate the pressure that the pump/motor must provide to overcome the load and fluid resistance of the system to do active work. This is the working pressure of the pump/motor unit.


The relief valve is then adjusted so that the opening pressure is higher than the working pressure of the pump/electrical set. The opening pressure of the valve can be determined from the manufacturer’s sample.

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