What is a Pneumatic Valve?

Pneumatic valves play an important role in pneumatic systems. Due to the fast switching, different designs and material types, they can be adapted to various applications and environmental conditions.

The structure of a pneumatic valve is characterized by a number of connections and a number of switching positions.

What exactly is a valve in pneumatics?

In pneumatics, valves are used as a switch between different machine parts. They determine how much air is let through and in which direction.

You can compare the operation of a pneumatic valve to the switch of a lamp. The moment compressed air arrives at a pneumatic valve, it is opened, the compressed air flows to the air cylinder. 

Function of a pneumatic valve

Each pneumatic valve basically consists of three elements, 2, 3 or 5 connections. The connections are also called ports.

A port provides the compressed air supply. In addition to a port, valves also consist of switching positions.

The gear positions take care of the work and venting.

The functions of a valve are indicated by two numbers. The first number represents the number of connections and the second number represents the switch positions.

Here are the available combinations:

• 2/2 valve  -  two ports and two positions - Used where air supply must be periodically regulated.

• 3/2 valve  -  three ports and two positions - Often used to control a cylinder or let out air.

• 5/2 valve  -  five ports and two positions - Widely used in double-acting cylinders.

• 5/3 valve  -  five ports and three positions - This valve can assume an intermediate position, for example to block a cylinder in a certain position.

Different valves in pneumatics

Not only the connections and switching positions determine the choice of which pneumatic valve you need. The way in which the valve is operated also determines the choice.

There are different types of valves:

Mechanical control: 

Through a physical action, such as pressing a button or moving a lever.

Electric actuation (solenoid valve):

By an electrical pulse that activates a solenoid coil and thus opens or closes the valve.

Pneumatic operation:

By a small amount of compressed air moving a diaphragm or piston.

Manual operation:

For example, with a rotary knob or pedal.

When a valve is activated, an internal valve opens or closes, directing the airflow in the desired direction. This controls the operation of pneumatic actuators, such as cylinders and motors .

Find out more about the operation of a pneumatic valve? Read all about it in our extensive blog.

Properties of a pneumatic 2/2 or 3/2 valve

• Normally closed (NC)
  In the idle or non-actuated position, the valve is closed. When we operate the valve, the valve opens and flow is possible.

• Normally open, also known as normally open (NO)
  In idle or non-actuated position, the valve is open. When we operate the valve, the valve closes and no flow is possible.

A 5/2 valve has 5 ports and 2 outputs with a switch function between the 2 positions.

The operation of this valve is in: 

• Monostable
  One control is available that must be operated continuously during the changeover time.

• Bistable
  The switch between the two positions always takes place by a short-term control signal on one of the two sides of the valve.   

A 5/3 valve has the same number of ports as a 5/2 variant, but with an extra switch position.

The so-called middle position, this offers an extra unserved position.

There are 3 different versions for this middle position:

• Open middle position: This type of valve has a center position that allows a cylinder to move freely.

• Closed middle position: With this type of cylinder, a double-acting cylinder can be stopped in an intermediate position.

• Press center position: This position remains under pressure in the middle position, and ready for quick actions. 

5/3 valves can also be bi- or monostable.

Applications of pneumatic valves

Pneumatic valves are widely used in various industries. Among other things, in industrial automation:

• Packaging

• Metal cutting

• Material transport

• Product sorting

You can find your most suitable pneumatic valve at Pneuparts

By now you know that pneumatic valves are used for various industries. When looking for the right valve, you have to pay attention to all kinds of factors. This includes application, operation and control.

If you have any questions or need advice about this, please feel free to contact us and we will be ready to help you further.