The Ins and Outs of Pressure Relief Valves

December 18, 2019

In many chemical and manufacturing industries, pressure relief valves — aka pressure release valves — are essential to everyday processes and safety. These valves are set to release pressure that has built up to avoid process upsets, equipment failures, or fire.

In short, pressure relief valves are crucial safety devices in industries where machinery relies on the release of pressure to continue operating.

The parts of a pressure relief valve

Pressure relief valves have three important parts to them: the valve itself, a sensor, and a reference force element.

The valve itself moves in accordance to the pressure placed upon it. When the pressure builds to high levels, the valve will move from its place to allow fluid to leave, releasing the pressure. It will stay in this position until the force of the spring in the valve is great than the pressure that has built up.

The sensor is pretty explanatory. This part of the pressure relief valve is under the spring and acts when pressure has built up. It can come in a piston or diaphragm style, but it is important that it is accurate. Diaphragm styles are preferred in low-pressure systems for greater accuracy, due to the ruggedness of a piston-style sensor.

Finally, the reference force element is comprised of the spring and it’s compressed to a certain stress level with an adjustment screw at the top of the valve. When the spring forces pressure on the sensor, it triggers the valve to open and allow that pressure to be released.

Maintaining pressure relief valves

Because pressure relief valves are a crucial safety device in machine operation and industrial manufacturing, it’s critical that they are installed, maintained, and repaired correctly and immediately if not in working condition.

Valve Magazine offers a great checklist of repairing and inspecting pressure relief valves, which includes:

1. Checking the condition of seal wires.

2. Visually inspecting the valve during disassembly to find any further damage

3. Properly cleaning parts, but not too aggressively as to damage them

4. Proper re-assembly of the valve when maintenance and repairs are completed.

Maintenance also includes testing the pressure relief valve, such as calibrating gages, set point tolerance, seal tightness and more.

Setting standards

Everyone on your staff that works with pressure relief valves in any capacity should be trained in looking for the signs of a malfunctioning or damaged valve. Luckily, The Blythe Company not only performs maintenance on pressure relief valves — among other important valves across industries — but also is an education partner for a variety of industrial companies and can be a partner with your company, too.

Contact The Blythe Company today for high-quality pressure relief valves as well as training and maintenance for your pressure relief valve needs.

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