The working principle of pressure reducing valve
Relief valve pneumatic control valve is a necessary accessories, main effect is to air pressure decompression and stability to a fixed value, so that the regulator can obtain stable gas source power for regulating control. According to the structural form can be divided into the diaphragm, diaphragm spring, piston, lever and bellows type; According to the seat number can be artificial single-seat and two-seater; According to the position of the disc can be divided into different function type and reaction type.
When the output of the pressure reducing valve, pressure higher or larger regulating directly with pressure regulating spring, the spring stiffness is too large, flow changes, the output pressure fluctuation is bigger, the structure size of the valve will also increase. In order to overcome these shortcomings, pilot operated pressure reducing valve can be used. Pilot operated relief valve working principle and straight acting basically the same. Pilot operated relief valve used in gas, voltage regulator is made up of small supply of straight moving type relief valve. If the small straight moving type relief valve is installed inside the body, is called the internal pilot operated relief valve; If the small straight moving type relief valve is installed on the outside of the main body, is called external pilot operated pressure reducing valve. As shown in figure 14-2 for the internal structure of pilot operated pressure reducing valve, compared with a straight moving type relief valve, the valve is increased by the nozzle 4, 3, 9 and fixed orifice gas damper chamber of the nozzle flapper amplification B. When the distance between the nozzle and the baffle is small change, can cause stress in the room B obvious changes, causing 10 have larger displacement of diaphragm, and 6 to control valve core to move up and down, the intake valve opening up or down, improves the sensitivity of control valve core, which improved the precision of voltage regulation.
