The pilot pressure reducing valve is composed of a valve body, main spring, main valve core, main valve seat, piston, pilot spring, pilot valve core, pilot valve seat, pilot piston, and adjustment spring. Turn the adjustment screw, compress the adjustment spring, and open the pilot valve core. The medium enters the upper part of the piston from the inlet side. As the piston area is larger than the main valve core area, the piston is pushed downwards to open the main valve. The pressure of the spring is adjusted by the pressure balance after the valve to change the opening of the pilot valve, thereby changing the pressure above the piston. Control the opening of the main valve core to maintain a constant pressure after the valve.

Compared to the direct acting pressure reducing valve, the remote control port of the pilot type pressure reducing valve has an important function, which is to connect it to another remote pressure regulating valve through an oil pipe (the structure of the remote pressure regulating valve is the same as the pilot control part of the pressure reducing valve). By adjusting the spring force of the remote pressure regulating valve, the hydraulic pressure at the upper end of the main valve core of the pressure reducing valve can be adjusted, thereby implementing remote pressure regulation of the outlet pressure of the pressure reducing valve, However, the pressure that can be adjusted by the remote pressure regulating valve shall not exceed the adjustment pressure of the pilot valve of the pressure reducing valve itself.