Pressure reducing valve working principle

Pilot piston type pressure reducing valve turn adjusting screw, the top channel valve disc, medium from the inlet side into the piston above, due to the piston area is greater than the main valve disc area, promote the piston moves down, makes the main valve is opened, a valve after pressure adjustment spring change pilot valve opening pressure, which changes the piston at the top of the pressure, control of main valve opening of the valve after pressure constant.
The guide above pneumatic control valve working principle. Thin film on cavity pressure is controlled by the bypass valve.
Pilot diaphragm pressure-reducing valve when adjusting spring in a free state, the main valve and pilot valve are closed. Clockwise rotate the handwheel, the pilot valve diaphragm downward channel valve, medium to flow through the pilot valve to the above the diaphragm, thus promote the main valve, make the main valve opens, media of exports, at the same time into the pilot valve beneath the diaphragm, the outlet pressure rise to and the spring force balance. Such as export pressure heighten, pilot valve diaphragm moving up, the pilot valve opening. At the same time into the main diaphragm below medium flow decreases, and pressure drop, outlet pressure lower reaches a new equilibrium, and vice versa.
Combined type pressure reducing valve pressure reducing valve by the main valve and pilot valve, cut-off valve. When adjusting spring in a free state, the main valve and pilot valve is closed. Turn adjusting screw, pushed by the media channel valve, rubber film chamber at the same time into the main valve to adjust the spring pressure balance, into the main valve rubber film chamber, rubber diaphragm up, the main valve is opened, the medium flow export , the export of medium and then feedback to rubber film chamber above and below the pilot valve chamber.
When the outlet pressure increased, of the diaphragm of the pilot valve, pilot valve opening degree is reduced, the chamber of the medium pressure drop, chamber pressure drop at the same time, the main valve rubber film down, the opening of the main valve is electric control valve, the outlet pressure drops, reaching a new equilibrium and vice versa.
Lever type pressure reducing valve at this time through the lever on the counterweight balance pressure reducing valve. Its action principle: when the lever is in free state, the double seat disc and seat closed. Under the effect of inlet pressure, the upward push disc, outlet pressure, balance weight, on the lever to adjust important to convey to the required outlet pressure.
When the outlet pressure over a given pressure, due to the medium pressure compared to the force acting on the seat to the seat of strength, forming a certain differential pressure, the valve moves down, in order to reduce the ball valve, outlet pressure drops, reaching a new equilibrium. The forerunner of bellows type pressure reducing valve structure principle with the guide piston type pressure reducing valve.