Pressure relief valve (Pressure Relief Valve) according to its structure and working principle
1. Direct-acting pressure relief valve
Definition: The medium pressure acts directly on the valve disc, overcoming the spring force or other loading device force to open the valve.
Features
Simple structure: No external energy is required, driven by the medium's own pressure.
Quick response: Suitable for occasions where rapid pressure relief is required.
Application: Widely used in gas, steam and liquid systems, such as boilers, pressure vessels, etc.
Subtype
Spring direct load type: Control the opening pressure by spring force.
Heavy hammer type: Use the weight of the heavy hammer as a loading device.
2. Pilot pressure relief valve
Definition: It consists of a main valve and a pilot valve, and the pilot valve controls the opening and closing of the main valve.
Features
High-precision control: The pilot valve can accurately adjust the opening pressure of the main valve.
Applicable to high-pressure systems: Can withstand higher system pressures.
Application: Commonly used in high-pressure equipment in chemical, petroleum, power and other industries.
Subtype
Snap-action pilot type: After the pilot valve is actuated, the main valve opens quickly and fully.
Proportional action pilot type: The opening height of the main valve is proportional to the system pressure.
3. Balanced pressure relief valve
Definition: The force of the back pressure on the valve disc is balanced through a special structure (such as a bellows), so that the opening pressure is not affected by the change of back pressure.
Features
Back pressure compensation: Suitable for occasions with large discharge back pressure.
Good stability: It can still maintain a stable opening pressure when the back pressure fluctuates.
Application: Commonly used in corrosive media or systems with unstable back pressure.
Subtype
Bellows balanced type: Use bellows to isolate the medium to prevent corrosion.
Other types
Power-driven pressure relief valve: Driven by external power (such as pneumatic, electric), suitable for special working conditions.
Safety relief valve: Combines the functions of safety valve and pressure relief valve, used in gas and liquid systems.
These types are selected according to specific application requirements to ensure that the system can safely relieve pressure under overpressure conditions.
