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Safety relief valves

Description

Safety relief valves are designed to keep the pressure bellow the preset pressure. Usually safety relief valves are placed after pressure regulator. Safety relief valves are releasing small amounts of gas if for some reason pressure increase above the preset activation pressure, like in the case of regulator not closing perfectly, or for sudden pressure increase in the event of gas line fast closing.

Thanks to their effective release capacity and compact size, our safety relief valves are ideal for use on gas metering and regulating stations for natural gas as well as on storage tanks for LPG, propane - butane mixture, hydrogen, nitrogen and other technical, non-corrosive gases reservoirs.

Our safety relief valves are extremely easy to install and are designed for ready and easy maintenance.

Operation

If the pressure under the diaphragm or seat of the safety relief valve is higher than the force generated by the preset spring, diaphragm is raised, causing the sleeve which is integrated with the diaphragm to move and the natural gas is released through an orifice.

Safety relief valve activating pressure is set by adjusting the compression of the spring through an appropriate ring. The set pressure should be an intermediate value between active regulator set pressure, and the activation pressure of safety shut off valve. It is recommended that set pressure for relief valve needs to be 15% higher than pressure regulator set pressure.

Installation

Safety relief valves are normally installed downstream of the pressure regulators. For keeping the pressure in the installation bellow the set pressure, gas from the installation has to released. Natural gas is thereby released into the atmosphere at an appropriate height. Also, gas release pipe diameter has to be at least the same as safety relief valve outside diameter. The direction of safety relief valve installation does not influence the performance of the valve.

Technical data

For proper safety valve selection, except flow capacity, several more technical informations are required:

Activation pressure[bar]
Operating temperature range[OC]
Ambient temperature range[OC]
Nominal diametersDN
Standard pressure categoriesPN
ConnectionG, Rp, Rc, NPT, RF

Materials

Commonly used materials for safety relief valves working with natural gas and LPG, as non corrosive medium, are carbon steel with nitrile rubber for control diaphragm, like one example given bellow:

Valve body casingC22.8, AlSi, CuZn
Diaphragm80NBR
Seals 80NBR

If you have any additional questions or inquiries, feel free to contact us!

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