First, the working principle
Pilot operated pressure reducing valve
The pilot-operated pressure reducing valve changes the flow rate and the kinetic energy of the fluid in the pipeline system by changing the throttle area. After different degrees of pressure loss, the internal pressure reduction of the pipeline is achieved. The internal pressure of the valve is controlled by careful control and adjustment. The fluctuations and spring forces reach a balance that ultimately keeps the post-valve pressure in the pipe constant within a certain margin of error.
The pilot operated pressure reducing valve uses hydraulic working principle to achieve control. As a partial pressure change adjustment and throttling component, the pilot pressure reducing valve reduces the inlet pressure to a set outlet pressure range, and then relies on the energy of the medium to automatically maintain the outlet pressure. valve.
2. Proportional pressure reducing valve
The proportional pressure reducing valve is a pressure reducing valve that controls the pressure behind the valve according to the numerical ratio. The ratio of the pressure before the valve to the pressure after the valve is 2:1, 3:1, and so on. The post-valve pressure changes with the change of the pre-valve pressure, and the post-valve pressure is not kept constant, but only maintains a certain ratio with the pre-valve pressure. When the pressure in front of the valve increases, the pressure behind the valve increases proportionally. When the pressure in front of the valve decreases, the pressure behind the valve decreases proportionally, keeping the ratio of the inlet and outlet pressure of the pressure reducing valve constant.
Second, the setting requirements
1. The pressure reducing valve should be placed in front of the alarm valve group inlet. When connecting two or more alarm valve groups, an auxiliary pressure reducing valve should be provided.
2. A filter should be installed at the inlet of the pressure reducing valve. The diameter of the filter mesh should not be less than 4 mesh/cm2 to 5 mesh/cm2, and the flow area should not be less than 4 times the cross-sectional area of the pipe.
3. Pressure gauge should be installed before and after the filter and pressure reducing valve. The diameter of the dial of the pressure gauge should not be less than 100mm, and the maximum range should be twice the design pressure.
4. The control valve should be set in front of the filter and after the pressure reducing valve.
5. A pressure test drain valve should be provided after the pressure reducing valve.
