Guizhou Hydraulic Lock: Applications of Threaded Cartridge Valves in Hydraulic Pumps

Threaded cartridge valves are selected for hydraulic pumps. Since hydraulic pumps integrate hydraulic solenoid valves, compact solenoid valves are required, which promoted the R&D and design of threaded cartridge flow control valves. The threaded cartridge flow control valve was among the first developed and widely adopted threaded cartridge valves. Threaded cartridge products and threaded cartridge one-way throttle valves are further applied to hydraulic pumps. Modern hydraulic pumps are equipped with a large number of threaded cartridge valves.

Threaded cartridge valves are used to set the high working pressure for the main hydraulic pump and charge pump. This type of threaded cartridge valve is used to open or cut off oil passages. When system faults occur, ports A and B are connected via threaded cartridge stop valves to facilitate towing or pulling of construction machinery. The threaded cartridge pressure-differential unloading valve adjusts the pump’s outlet pressure to vary with load pressure.

With continuous advancement in threaded cartridge valve technology, multi-function valves dedicated for pumps have been developed. Hydraulic power system manufacturers integrate four valve functions: threaded cartridge flow control valve, threaded cartridge differential pressure flow control valve, threaded cartridge check valve and threaded cartridge stop valve.

Threaded cartridge valves are also commonly used in hydraulic motors, especially closed-circuit test motors. The structure and circuit diagram of the closed-circuit test variable motor from the threaded cartridge valve supplier are shown below. Four threaded cartridge valves are fitted in this hydraulic power unit.

• The threaded cartridge valve regulates the system oil change pressure.
• The threaded cartridge shuttle valve delivers pressurized oil from the high-pressure side to port P of the solenoid directional pressure reducing valve.
• The threaded cartridge solenoid directional pressure reducing valve controls motor venting.
• The threaded cartridge 3/3-way shuttle valve (also known as threaded cartridge oil shuttle valve) connects to both sides of the motor in the closed test control circuit. During forward and reverse system operation, it ensures a certain volume of residual oil on the high-pressure side returns to the tank, realizing cooling of the closed test control circuit.