Principle and structure of pressure reducing valve

The pressure reducing valve belongs to the automatic valve type. When the air source pressure of the high-pressure oxygen tank is higher than 0.8 MPa, the pressure reducing valve shall be set. With the help of the energy of compressed air itself, the pressure reducing valve can keep the outlet pressure stable automatically.

Working principle of pressure reducing valve: the principle of pressure reducing is to use sensitive elements such as diaphragm, spring and piston to change the clearance between valve core and valve seat to achieve the purpose of automatic pressure reduction. The lower part of the valve body is equipped with a main valve spring to support the main valve core, so that it is in a sealed state with the valve seat. The plug on the lower end cover is used to drain the liquid in the valve. There are cylinder plate, cylinder sleeve, piston and piston ring in the upper cylinder of the valve body. The pilot hole in the middle of the cylinder plate is matched with the main valve stem, and the piston is placed on the main valve stem. When the piston is under the medium pressure, the valve core in the workshop is pushed down through the main valve stem to open the main valve. The valve cover is equipped with the spring, valve core and valve seat of the auxiliary valve, and the valve core is covered with a stainless steel diaphragm. The cap is equipped with adjusting spring, adjusting screw and lock nut.

Structure of the pressure reducing valve: the piston type pressure reducing valve is mostly used for the pressure reducing valve of the air source of the high-pressure oxygen cabin. It is mainly composed of valve body, valve cover, piston, spring, main valve, auxiliary valve and diaphragm.

Pressure regulation of pressure reducing valve: remove the safety cover, loosen the lock nut, turn the regulating screw clockwise, the pressure at the outlet of pressure reducing valve will increase, otherwise it will decrease. When the adjusting screw is turned clockwise, the auxiliary valve is opened, and the compressed air enters the upper part of the piston from the inlet through channels a, B, auxiliary valve and C. because the area of the piston is larger than that of the main valve core, the piston moves downward after being stressed to open the main valve core. The compressed air flows to the outlet and enters the lower part of the diaphragm through channels D and e at the same time, and the outlet pressure rises gradually until the required peak value Balance with spring force. After the pressure is adjusted, tighten the lock nut and install the safety helmet. When adjusting the pressure, the air source pressure should be at the highest working pressure, as shown on the pressure gauge before pressure reduction. The outlet pressure of pressure reducing valve should be 0.6 ± 0.02MPa.