Differences and similarities between pressure reducing valves, safety valves, pressure stabilizing valves and pressure relief valves

1. Pressure reducing valve

A pressure reducing valve is a valve that reduces inlet pressure to a desired outlet pressure through regulation, automatically maintaining a stable outlet pressure by relying on the energy of the medium itself. From a fluid mechanics perspective, a pressure reducing valve is a throttling element with variable local resistance. This means that by varying the throttling area, the flow rate and kinetic energy of the fluid are altered, resulting in varying pressure losses, thereby achieving the purpose of reducing pressure. The control and regulation system then balances pressure fluctuations downstream of the valve with the spring force, maintaining a constant pressure within a certain tolerance.

(1) Used to reduce high-pressure fluid to the required low pressure level to meet system requirements.

(2) Able to stably control the output pressure and ensure that the system can maintain a constant pressure at any flow rate.

(3) Usually installed on high-pressure pipelines.

2. Safety valve

A safety valve is a special valve that is normally closed when an external force is applied to the opening and closing parts. When the pressure of the medium in the equipment or pipeline exceeds the specified value, the medium is discharged to the outside of the system to prevent the pressure of the medium in the pipeline or equipment from exceeding the specified value. Safety valves belong to the automatic valve category and are mainly used in boilers, pressure vessels and pipelines to control the pressure not to exceed the specified value, playing an important protective role in personal safety and equipment operation.

(1) A device used to protect equipment and systems from damage caused by excessive pressure.

(2) When the system pressure exceeds the preset safety value, it will automatically open and release excess pressure.

(3) Usually installed upstream of key equipment or systems.

3. Pressure stabilizing valve

A pressure stabilizing valve is a device that keeps the medium in an area within a certain pressure range. Differences from pressure reducing valves:

Pressure reducing valve: Reduces the outlet pressure to the rated value regardless of changes in the inlet pressure, thus reducing pressure.

Pressure stabilizing valve: Maintains a constant upstream pressure regardless of changes in downstream pressure and demand.

(1) A device used to maintain a stable system pressure.

(2) It works when pressure fluctuates, maintaining a constant pressure by adjusting the flow rate of the fluid.

(3) It is usually used in situations where high-precision pressure control is required.

4. Pressure Relief Valve

When the pressure within a device or pipeline exceeds the set pressure, the pressure relief valve automatically opens to relieve pressure, ensuring the pressure of the medium within the device and pipeline remains below the set pressure, protecting the equipment and pipeline and preventing accidents. Pressure relief valves are primarily used in situations where excessive pressure is present. When the pressure exceeds the set value, the valve disc opens, releasing pressure immediately. Once the pressure decreases, the valve returns to its original position. Pressure relief valves are similar to safety valves, with pressure relief valves typically used for liquids, and safety valves typically used for gases and steam.