The 500X Pressure Relief valve is a hydraulically controlled  valve, also known as a Sustaining/ Relief valve. It belongs to the hydraulic control  valve series and is extensively used in water  force and drainage systems. Its main functions are to  help system overpressure, maintain a specified pressure, and  cover the safety of channels and outfit.

A.Pressure relief working mode
The main valve is installed in the drain bypass, parallel to the main channel.
When the system pressure exceeds the set value of the airman valve, the airman valve opens, reducing the pressure above the main valve cover.
Driven by the pressure difference between upstream and downstream, the main valve opens fleetly to discharge redundant fluid and lower the system pressure.
When the pressure drops below the set value, the airman valve closes, the pressure above the main valve cover is restored, and the main valve closes.
B.Pressure-holding working mode
Acclimate the airman valve to the sustaining pressure mode, and the main valve remains unrestricted.
When the upstream pressure falls below the set value, the airman valve closes and the main valve does n’t open.
This ensures the upstream system maintains pressure above the set value to meet specific water force conditions.