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How Back Pressure Reducing Valve Works

Back Pressure Valve

What is a Back pressure-reducing valve?

A back pressure-reducing valve or back pressure regulator is a device that maintains a constant pressure upstream of its inlet. When the process fluid pressure in the regulator’s inlet exceeds the setpoint, the regulator opens to release the excess pressure. The primary function of the back pressure regulator is to control the pressure of fluid, gas, or mixture in a system. Most pumping applications use this regularly. Innovative Back pressure-reducing valve optimize system operations

Pressure relief valve vs back pressure regulator

The primary similarity between the pressure relief valve and the back pressure regulator is to control the level of pressure. However, there is a difference in the method of operation. The pressure relief valve is a safety device that automatically opens and closes depending on the pressure and the need to release, on the other hand, a back pressure regulator is a constantly moving application with pressure sensors that react accordingly. The back pressure regulator is not just a safety device but an integral part of the system.

Working principle of pressure valve

The Back Pressure Valve is an integrated device The pilot responsible for opening and closing the valve is attached to the valve and comes out as one piece.

The upstream pressure of various kinds of fluid, liquid, or gas is monitored through the valve. To change the set point to a desired level just turn the adjustment bolt on the top.

The spring compresses the diaphragm assembly, causing the pilot plug to be positioned. The gas can then push downward on the diaphragm from upstream thanks to the pilot plug.

The flow through the valve originates beneath the plunger. As the gas pulls down on the diaphragm, the flow pushes up on the plunger. As the diaphragm has a bigger surface area than the plunger, the same pressure can close the valve. This maintains a steady back pressure and the valve begins to regulate the pressure.

If the pressure reaches the set point, the upstream pressure pulls up on the diaphragm assembly, sealing it off. The gas then vents from the diaphragm’s top and the valve controls the upstream pressure.


The back pressure regulator is used in industries including the food and beverage industry, high-pressure application, fuel and oil burner control, and oil atomization.

Check the below-discussed factors if the back pressure regulator is not operating smoothly

Is the stopper in the breather plug still fixed?

The small red stopper on the breather plug has not been removed then the regulator gets stuck in the ON position. The stopper is a temporary unit, to prevent oil spillages during transport. Before proceeding with operations manually remove the stopper.

Is the pilot plug seat loose?

If the pilot plug is not fixed tightly the regulator would not open To solve the issue remove the then-net and the pilot housing and access the pilot plug seat. Check the pilot plug seat with a wrench.

Is the seat nut too tight?

The seat nut should not be too tightened otherwise the seat bulges. Then the regulator starts leaking downstream. All you need to do is back off the nut a quarter turn at a time until the seat is flat.

Is your petrol damp or dirty?

If your regulator is constantly venting, you might have a damaged diaphragm or the lot plug that is unable to seat properly owing to moist or unclean gas in your pipelineIn such cases y, you have to remove both the net and pilot housing and access the pilot plug Thee pilot plug should then be removed, cleaned and dried, and reinstalled.

How to identify the valve

Specific data is provided on back pressure regulator housing. The marking must contain information like

  • Name of the manufacturer
  • Nominal width
  • PN designation
  • Maximum allowable pressure
  • Maximum allowable temperature
  • Material
  • Order number
  • Type of valve
  • Year of manufacturing

Bottom line

A back pressure regulator is an integrated device with pilot housing to maintain constant upstream pressure. It is slightly different than a pressure relief valve. Purchasing the appropriate valve is crucial If the regulator is not working properly, remove the pilot plug and investigate various causes.

Some related questions

How to choose a back pressure regulator?

Checking the flow curve frequently, as supplied by the manufacturer, is the optimum way to choose a regulator for your application.

Why do I need a back pressure regulator?

A back pressure regulator controls the pressure of any fluid or gas. Most pumping applications require back pressure to be positioned on the outlet of the system.

What Material is used in the back pressure regulator?

Common regulator components include brass, plastic, and aluminum. Additionally, stainless steel comes in a number of grades.