Difference between pressure relief and control valve?

09 Jan.,2023


Both pressure relief valves and pressure control valves have their own unique uses within fluid control and gas control applications. Pressure control valves and pressure relief valves have unique attributes that make them best suited to a number of very distinct and different applications. If you’ve found yourself wondering what a pressure control valve is, and the difference between the two pressure valve types, read on to learn more. Here, the fluid handling experts at Fluid Controls explain the difference between the two components; explaining the features, safety information and benefits of each valve type. 

What is a pressure relief valve?

A pressure relief valve is a type of safety valve that is used in a process control system to limit or control the pressure in a system. This prevents pressure from building up, which could cause a devastating process breakdown, including equipment failure. 

This means that pressure relief valves are designed to be set at a specific pressure to protect the equipment from reaching a pressure that could damage expensive equipment. 

What are the features of a pressure relief valve?

Pressure Relief Valves (PRV) were first used on steam boilers during the industrial revolution. Early boilers without them were prone to accidental Explosion due to their lack of safety features.

A pressure relief valve is a static device that can reduce pressure even if there is no flow coming out of the reservoir. They are designed to open proportionally to increasing pressure and therefore are not recommended for applications requiring immediate full valve flow at a set pressure.

The full flow of the relief valve is defined at 10% over set pressure and the two general types of protection encountered in industry are thermal protection and flow protection. These precision valves are designed for pressure gas systems, cryogenic systems, petrochemical applications and other special systems. The pressure relief valve features are designed to EN ISO 4126-1 standard, they have a lower whole lifetime cost and they optimise outlet flow for faster relieving. These valves usually release in to the drain or environment meaning that the steam or fluid that goes into the pressure release valve is naturally lost to the system.

What is a pressure control valve?

Similar to a pressure relief valve, a pressure control valve can protect a system from the damages which is caused by excessive pressure. These valves are often found in hydraulic systems and are used to protect the hydraulic system. 

Hydraulic systems employ pressure control valves in order to limit the level of maximum pressure which can protect the pump or system from overpressure. 

What are the features of a pressure control valve?

A Pressure Control Valve (PCV) on the other hand, acts to change resistance to the flow of the fluid, but does not alter its destination. Fluid that passes through the Pressure Control Valve is still going to the destination it was proposed for and is not lost.

These valves are found in virtually every hydraulic system, and they assist in a variety of functions, from keeping system pressures safely below a desired upper limit to maintaining a set pressure in part of a circuit.

The pressure control valve features guarantee the performance of the system and optimisation of energy usage. Exact and precise control of differential pressures eliminates overflows at partial conditions and controls the temperature at low load conditions.

Here at Fluid Controls, we are proud to be able to offer a range of control valves from some of the leading names in process and fluid controls, including Burkert and Welker. 

The difference between a relief valve a control valve

The main difference between PRV and PCV is that the PCV is called a first-line defence which is meant for primary safety. The PRV is not used as a pressure control device but as a backup of last resort. Pressure Control Valves are ideal for applications requiring a reduced pressure to a cylinder whereas Pressure Relief Valves are used to maintain a preset downstream pressure.

Buy pressure control valves and pressure relief valves from Fluid Controls.

Here at Fluid Controls, we don’t just have the knowledge and expertise to explain what a pressure control valve is, and its difference from a pressure relief valve. We can also support you in making the correct choice of pressure control valve and pressure relief valve for your application. For more information about any of our products at Fluid Controls call us today on 0118 970 2060