What is a Pneumatic Regulator?

by Justin Uhm

In this post, I will explain what a pneumatic regulator is and what it does. I will also cover all the different pressure control valves (a type of regulator), and I will explain the operating functions of these differing regulators.

Pressure Control Valve (aka Regulators)

Usually, compressed air sent from the air compressor to a pneumatic system through the purification system is more highly pressured than the system and is decompressed before reaching the system. If air from the air compressor is not decompressed before it is supplied to the driver apparatus, the instability of the air will affect the driver apparatus or it will output unnecessarily high force to cause various troubles and reduce the lifespan of the equipment. 

Therefore, a pressure control valve, or a pneumatic regulator, is used to maintain air pressure. Following are the functions of pressure control valves:

  • Uses air pressure that is appropriate for the driver apparatus to prevent any waste of compressed air. 
  • Controls the air pressure at the bottom of the pneumatic line that fluctuates according to the air usage to supply consistent air pressure. 
  • Operates the driver apparatus with the appropriate air pressure for the durability and reliability of pneumatic drives. 
  • When the apparatus rises above the set pressure, the regulator releases some air for safety.
  • Converts the existence of air pressure into electrical signals for monitoring or to control solenoid valves and other devices.

The following sections discuss the different types of pressure-reducing valve regulators.

Pressure Reducing Valve Regulator

A regulator (also known as a pressure-reducing valve) reduces the pressure of compressed air from the aerial power source and adjusts the secondary air pressure to the preset air pressure. Even if the primary pressure fluctuates or the amount of use for using the secondary air Secondary air controls preset air pressure to supply stable air pressure.

Pressure Reducing Valve also reduces humidity in compressed air. Regulators are mostly used in normal aerial circuits; pilot type regulators are used in circuits that require a high level of precision. 

Direct-Type Regulator

A direct-type regulator can be operated manually by a handle or mechanically using a cam.

A manually operated pressure-reducing valve, as shown in Figure 1.1, opens the valve for the primary air supply, while the handle is used to manipulate the spring.

The air pressure that corresponds to the control spring force works on the diaphragm to control the surface area of air passageway to the valve so that the secondary air pressure is balanced with the control spring force.

The pneumatic system often sees the secondary air pressure going higher than the preset air pressure. For example, an unexpected load pushes the piston out while operating the pneumatic cylinder, causing the secondary air pressure to go higher than the preset air pressure. 

Different components of a regulator
Figure 1.1


In this case, the diaphragm is raised by the stem, as shown in Figure 1.2, to release the secondary air into the atmosphere to return to the preset pressure. This type of pressure reducing valve is called a relief type; valves without the relief hole are called non-relief pressure-reducing valves. 

Example of a control spring compression and secondary pressure compressing on the diaphragm
Figure 1.2

A non-relief pressure-reducing valve has no discharge opening on the relief valve sheet and cannot reduce the secondary pressure if there is no consumption of secondary air. However, non-relief valves are widely used for secondary air release and are designed to allow discharge. 

A bleed-type pressure-reducing valve include a port that discharges secondary air in small amounts. A bleed-type pressure-reducing valve improves flow characteristics and the lag in a low-flow area, it enables more sensitive pressure control. 

Pilot Type Pressure Reducing Valve

A pilot-type pressure-reducing valve, also known as a precision regulator, has an embedded pilot device in the pressure-reducing valve and is used to control pressure with high precision by sensitively responding to the fluctuations in secondary air pressure.

Pilot-type pressure-reducing valve is classified as both a precision type and high-capacity type of valve.

Precision type valves are used for various testing, inspections that require highly precise pressure control, or for remote-control pilot pressure signals. 

As shown in Figure 1.3, a pilot-type pressure-reducing valve closes the pilot valve when the handle is turned to compress the control spring and compress the primary airflow into the secondary area when the main valve is opened by the nozzle back pressure. 

Components that make up the pilot-type pressure reducing valve
Figure 1.3

Selecting a Pneumatic Regulator

As you can see, there are many types of regulators, so how do you know which one to pick? Below, I list some of the issues to consider, so you can make the right choice for the application at hand. 

When selecting a regulator, the following issues should be considered:

  • The size and fluctuating of primary pressure
  • The size and fluctuation of pressure required by the secondary area
  • Precision of pressure
  • The amount and fluctuation of air in use

The points above must be carefully reviewed to select a regulator that is suitable for all conditions.

From an economical point of view, it would be good to install one high-capacity regulator to cover several areas, but as mentioned above, secondary pressure is fluctuated by the fluctuation in the amount of air that passes through the regulator. Therefore, it is safer to choose and install regulators that are suitable for each area. 

This concludes information on regulators. I hope this has been informative to everyone and for more information on topic like this, follow us on social media. Or to contact us, click here. Visit our pneumatics components store at https://store.tpcautomation.com.

This is one of three articles about pneumatics components called FRLs. See the other FTL posts here:

Have a pneumatics question? Click the button below.

Ask a TPC Pneumatics Expert a Question