fluorine lining gate valve

Troubleshooting and Removal of Pressure Reducing Valves

by:Lianke Valve     2022-06-25
Troubleshooting and troubleshooting of pressure reducing valves In hydraulic systems that require high-pressure fluid and secondary high-pressure fluid, pressure-reducing valves are often used to provide secondary high-pressure fluid. D-JF1 pressure reducing valve has outstanding advantages such as reliable action, convenient and flexible pressure regulation, and stable operation. 1. Working principle D-JF1 pressure reducing valve is shown in Figure 1. It consists of valve body, valve core, valve seat, piston, safety valve, adjusting screw, accumulator, guide sleeve, pressure bearing ring, filter, etc. The valve seat and piston slide up and down. The working principle of D-JF1 pressure reducing valve: use the gap between the valve core and the valve seat to throttle, so that the output pressure is lower than the input pressure; at the same time, the output pressure feedback, acting on the piston, forms a dynamic balance with the gas spring force, and automatically adjusts the valve The gap between the core and the valve seat keeps the output pressure constant. During the working process, when the outlet pressure changes, the force state of the piston will be changed instantly, and the piston will be forced to rise and fall. The resultant force on the spool is always upward, so that the spool rises and falls with the piston at the same time until a new equilibrium position is reached, thereby keeping the pressure regulation value constant. The accumulator is pre-charged with nitrogen with a certain pressure, which is used as a gas spring. Adjust the pressure of the D-JF1 pressure reducing valve by changing the accumulator pressure with the adjusting screw. Slowly open the screw on the liquid inlet side, the high pressure liquid enters the lower part of the accumulator, the nitrogen gas is compressed, the pressure increases, the piston moves down, the valve gap increases, the throttling effect weakens, and the outlet pressure increases; on the contrary, open the liquid outlet side screw, then The liquid decreases, the pressure drops, the piston moves up, and the outlet pressure decreases. 2 Existing problems and improvement measures (1) Air leakage of the accumulator When the accumulator is put into the water, if there are bubbles in the water, the air leakage of the accumulator is detected, which is mostly caused by the poor sealing of the inflation valve. The charging valve on the D-JF1 pressure reducing valve accumulator adopts an M8 socket head cap screw, and a plane is cut along the length of the thread part, and a combined sealing washer is used to seal it. Special tools are required to check the gas pressure. (2) Leakage of adjusting screw D-JF1 pressure reducing valve is a poppet valve. Due to its structure and manufacturing, it is difficult to make it close without leakage. After modification, it is sealed with a steel ball, and the effect is very good. (3) The piston is stuck at the highest position. There are 2 small holes in the upper part of the inner hole of the guide sleeve that matches the outer circle of the piston. The pressure is too low to meet the requirements. A better way is to add a relief groove to remove the burrs on the inside of the upper two small holes in the guide sleeve hole. (4) The O-ring of the outer diameter of the guide sleeve is easy to be cut and damaged. The original design of the seal between the valve body and the guide sleeve is that the O-ring is installed in the hole of the valve body. In order to facilitate processing, it is now installed on the guide sleeve, but the valve body hole The mouth does not have a 20° chamfer, which makes the O-ring easy to be cut during assembly. 3 Common faults and troubleshooting methods (1) No decompression ① The pressure is too high, check and inflate to 2.5~4.5MPa; ② The left adjusting screw leaks, and the inner taper hole at the bottom of the connecting hole is repaired; ③ The opening of the valve seam is too large , the piston is stuck at the lowest position, the piston and the guide sleeve are not matched with each other, and the matching step hole is polished. (2) The outlet pressure is too low to be adjusted up ① The accumulator leaks. Check and inflate to the specified value; ② the right adjusting screw leaks. Trim the inner taper hole at the bottom of the connecting hole; ③The opening of the valve seam is too small, and the piston is at the highest position. Remove the guide sleeve and polish the matching step hole. (3) The outlet pressure fluctuates and is unstable ① the accumulator leaks, check and inflate to the specified value; ② the left and right adjusting screws are not well sealed, and the inner cone hole at the bottom of the connecting hole is repaired. 4 Precautions Pay attention to the following two points in daily application: (1) Clean the filter frequently; (2) Regularly check the gas pressure of the accumulator and inflate it to the specified value.
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