The Principle of Pressure Reducing Valve in Hydropower Station
Author: source: date: 2020-05-20 11:17:52
Today I would like to share with you the pressure relief valve used in conjunction with the installation of hydropower stations and turbines.
We often become pressure-reducing valves for pressure-reducing valves. It uses the opening degree of the opening and closing parts in the valve body to adjust the flow of the medium and reduce the pressure of the medium. Keep the pressure behind the valve within a certain range, and spray cooling water in the valve body or behind the valve to reduce the temperature of the medium. This valve is called a decompression and temperature reduction valve. The automatic selection of pressure relief valve quick and easy is included. The characteristic of this valve is to keep the outlet pressure and temperature value within a certain range under the condition that the inlet pressure keeps changing.
The working principle of the pressure reducing valve: the pressure reducing valve uses the opening degree of the opening and closing member in the control valve body to adjust the flow rate of the medium, and reduces the pressure of the medium. The back pressure is kept within a certain range, and cooling water is sprayed into the valve body or behind the valve to reduce the temperature of the medium. This valve is called a decompression and temperature reduction valve. The automatic selection of pressure relief valve quick and easy is included. The characteristic of this valve is to keep the outlet pressure and temperature value within a certain range under the condition that the inlet pressure keeps changing.
(1) Pressure regulation range: It refers to the adjustable range of the output pressure P2 of the pressure-reducing valve. Within this range, it is required to achieve the specified accuracy. The pressure regulating range is mainly related to the rigidity of the pressure regulating spring.
(2) Pressure characteristics: It refers to the characteristics of output pressure fluctuations caused by input pressure fluctuations when the flow rate g is a fixed value. The smaller the output pressure fluctuation, the better the characteristics of the pressure reducing valve. The output pressure must be lower than the input pressure-the fixed value basically does not change with the input pressure.
(3) Flow characteristics: It refers to the input pressure-timing, and the persistence of the output pressure with the change of the output flow g. When the flow rate g changes, the smaller the change in output pressure, the better. Generally, the lower the output pressure, the smaller the fluctuation of it with the change of output flow.
It can reduce the higher liquid pressure in the pipeline before the valve to the level required by the pipeline behind the valve. The transmission medium here is mainly water. Pressure relief valves are widely used in high-rise buildings, areas with high water pressure in urban water supply networks, mines and other occasions to ensure that the water points in the water supply system get the proper service water pressure and flow. In view of the fact that the water leakage rate and the degree of waste are almost proportional to the water pressure of the water supply system, the pressure reducing valve has the function of improving the system operating conditions and potential water saving. According to statistics, the water saving effect is about 30%.
1. Close the gate valve before the pressure reducing valve and open the gate valve behind the reducing valve to create a downstream low-pressure environment;
2. Turn the adjusting screw counterclockwise to the uppermost position (relative to the lowest outlet pressure), and then close the gate valve behind the pressure reducing valve;
3. Slowly open the gate valve in front of the pressure reducing valve to fully open;
4. Slowly turn the adjusting screw clockwise to adjust the outlet pressure to the required pressure (based on the gauge pressure behind the valve); after adjustment, lock the lock nut and open the gate valve after the pressure reducing valve;
5. If the outlet pressure is higher than the set pressure during the adjustment, it must be readjusted from the first step, that is, it can only be adjusted from low pressure to high pressure.