Fluid Controls Ltd is one of the UK’s leading distributors for pressure control

Parker high pressure relief valves

Difference between a Pressure Relief & Control Valve

What is the difference between a relief valve and a control valve? Here, Fluid Controls explains the difference between the two components, explaining the features, safety information and benefits of each.

Pressure relief valve features

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 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 life time 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.

Pressure control valve features

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 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 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.

The difference between a relief valve and a control valve

The difference between PRV and PCV is that the PCV is called as 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 pre-set downstream pressure.

For more information about any of our products at Fluid Controls call us today on 0118 970 2060

Latest News

Why you should choose Welker Jet® control valves The Welker Jet® is the only natural gas control valve designed by a natural gas engineer specifically for the needs of the natural gas industry. Invented in 1958 by Robert H. Welker, founder of Welker Engineering, the Jet® is still untouchable more than 60 years later. No other control valve can... Read More
Introducing our range of Welker products Welker Engineering manufactures specialised instrumentation for the oil and gas industry. Their extensive product line provides a wealth of effective solutions for countless oil and gas applications, from sampling to conditioning, filtering, regulation, injection, containers and control. All of their... Read More
What is a flow switch? A flow switch can perform a range of functions across a variety of applications. Designed to control the flow of liquid or gas through a designated channel, flow switches are used to monitor flow rates of liquids, protect pumps and trigger alarms if the flow is too high or low. Here, Fluid Controls... Read More
Introducing the Norgren air pressure regulator range Air pressure regulators are found in most industrial settings, from processing plants to manufacturers and repair and maintenance facilities. Any setting where compressed air or gases are used will have an array of air pressure regulators in use to ensure a safe environment where equipment can function... Read More
How Parker tube fittings can benefit your processes For guaranteed leak-free and secure connections, there are no better industrial tube fittings on the market than Parker tube fittings. As a revered name in the manufacturing world, Parker flow control equipment is synonymous with innovation - a quality that extends to their industrial tube fitting... Read More