What are the Main Types of Hydraulic Pressure Relief Valve?

What are the different types of hydraulic pressure relief valves?

There are many kinds of sanitary pressure relief valves, they can be divided into two general categories: direct-action type and indirect-action type. The direct-action type uses the energy of the medium itself to control the required pressure. The Indirect-action type uses external power, such as air pressure, hydraulic pressure, or electric power to control the required pressure. Compare these two types, and it’s easy to conclude that the former has a relatively simple structure while the latter has higher precision.

According to the structure of pressure relief valves, they can be divided into:

Piston-type pressure relief valve:

It uses the piston to balance pressure and drive the movement of the valve flap.

Membrane-type pressure relief valve:

It uses a membrane as a sensing element to drive the movement of the valve flap.
Air bag-type pressure relief valve: It uses the pressure produced by the medium entering the air bag to balance pressure.

The above classification method is based on the structure of the valve.

According to the types of valve seats, they can be divided into single-seat valves and double-seat valves.

On the one hand, a double-seat valve can make the force on upper and lower seats mostly balanced and offset, reducing the resultant effect on the valve stem.

On the other hand, a larger channel area can be achieved, and the overall size of the valve can be reduced. However, the valve seat technology of the pressure relief valve is not good, and machining and grinding of it are difficult. The Assembly size chain should be well controlled in order to ensure assembly accuracy, making the valve normal and stable when working.

Conclusion

Different types of hydraulic pressure valves include relief, reducing, sequence, counterbalance, safety, and unloading. All of them are typically closed valves, except for reducing valves, which are usually open. For most of these valves, a restriction is necessary to produce the required pressure control.