Principle of Differential Pressure Valve
The pressure difference between the high-pressure source (water supply pipe) and the low-pressure source (water return pipe) changes, and the opening of the guide valve changes accordingly when the pressure difference between inlet and outlet of the main valve changes. The guide valve is open large when the pressure difference is large, and the main valve control room is drained, the pressure of the main valve control room decreases, the opening of the main valve increases, and the pressure difference between the inlet and outlet of the main valve decreases. Conversely, if the pressure difference between the inlet and outlet of the main valve decreases, the opening of the guide valve decreases, the pressure of the main valve control room increases, the opening of the main valve decreases, and the pressure difference between inlet and outlet increases. This negative feedback effect stabilizes the differential pressure between the main valve inlet and outlet at the set pressure.