Back Pressure Relief Valve

 In Gas Regulators

A recent new product offering prompted a customer’s question, “what is the difference between a relief valve and a back pressure regulator, and which do I need?” With the entry of a new product offering, we also had to explain the back pressure relief valve.

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What’s the difference between a relief valve and a back pressure regulator?

Both the relief valve and backpressure regulator serve as a pressure control valve when pressure is too high, but they both function differently.

What is a pressure relief valve?

When there is a pressure buildup in the relief valve, the valve opens and releases the pressure. When normal pressure restores, the valve closes. A relief valve is typically a last line of defense to prevent an accident or catastrophic event.

What is a back pressure regulator?

A back pressure (backpressure) regulator maintains a defined pressure upstream of the device, at its inlet. When fluid pressure at the inlet exceeds the setpoint, the valve opens enough to relieve the excess pressure until returning to normal operating pressure. Backpressure regulators work similarly to relief valves, but a back pressure regulator provides steady-state pressure control rather than strictly on-off actuation.

What is a back pressure relief valve?

The Belgas 289 is a line of regulators that can function as either back pressure regulators to maintain upstream pressure or as high flow relief valves to provide overpressure protection. Using the Belgas 289 in combination with line pressure regulators (such as the Dungs FRS series) or even the Belgas P133/P134 residential and light industrial regulators when inlet pressures exceed 2 PSI is critical, as they do not have overpressure protection. To adhere to the international fuel and gas code, these regulators would require an OPD (overpressure protection device).

What is overpressure protection?

An overpressure protection device (OPD) protects downstream piping from dangerous pressure buildup if the regulator fails. A regulator commonly fails when debris builds up on its valve seat or orifice, keeping the regulator from shutting bubble-tight during periods of no gas usage. As a result, the gas continues passing through the regulator, and consequently, the pressure builds in the downstream piping.

Which device is correct for my application?

The correct device for any application has to be with the objective.

  • If you need to maintain a set-upstream pressure, the back pressure regulator is the correct product.
  • If you want to protect a pressurized system or vessel during an overpressure event, then the correct device is a relief valve.
  • If you have a regulator that does not have an OPD and inlet is around 2PSI (or more), consider the Belgas 289 Type to adhere to the gas code.

Belgas Back Pressure Relief Valve

P289 belgas

P289 Belgas

We are now offering Belgas type 289 back pressure regulators that function as high flow relief valves with adjustable set points. The Belgas 289 comes in three variations for different applications. The P289 is standard for high pressure, L289 is for low pressure, while the F289 is for pilot operated.

P289 an Over-Pressure Protection Device

The BelGAS P289 back pressure regulator performs as a high flow relief valve with an adjustable setpoint. It can serve as a standard relief valve to protect against over-pressurization in the downstream system. With its large diaphragm area and integral pitot tube booster, the Type P289 has a quick and smooth response to excessive pressure relief requirements, particularly within low-pressure settings. Optional regulator rebuild kits are also available.

F289 Pilot Operated Back Pressure Regulator

Belgas F289 Type Back Pressure Regulator Relief Valve

Belgas F289 Type Back Pressure Regulator Relief Valve

The Belgas F289 is a Pilot Operated Back Pressure Regulator that functions as a high flow relief valve with an adjustable setpoint. Use the F289 in place of a standard relief valve to protect against overpressurization in the downstream system. The pilot regulator allows for accurate back pressure control with minimal buildup over the set pressure for the main valve’s full opening.

If you’re in need of a natural gas regulator, simply message us with your needs.

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Image by TheoRivierenlaan from Pixabay

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