The type of valve you need depends on the way of control.

Types of valves:

• Solenoid valve
• Pneumatic valve
• Mechanically operated valve
• Electrically actuated valve
• Manual valve

How a pneumatic valve works

The operation of a solenoid valve is usually indicated by a symbol

• The square frame stands for 1-switch position (several squares mean multiple switch positions)
• The lines in the frame represent the connections. These are indicated in the box that shows the normal position/resting state. (usually right)
• The arrows in the frame indicate the direction of flow.

5/3 valve
This valve has five connections and three switching positions (5/3). For example; Connection 1 is the connection to the compressed air supply. Connections 2 and 4 are connections to a double-acting cylinder and 3 and 5 are vents.

Properties of a 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. We call this Normally Closed or NC.

Sent directly

The sealing gasket pulls a plunger towards it. This immediately opens or closes the opening. No differential pressure is required (works from 0 bar).

Indirectly controlled

Indirect- or servo-controlled solenoid valves use the differential pressure of the medium to open or close. The minimum differential pressure is usually 0.5 bar. Because the liquid pressure is used, a relatively small coil can still control a large diaphragm and thus a high flow rate.

Semi direct controlled

In this version, the sealing diaphragm is directly connected to the plunger. When the coil voltage is switched on, the plunger is pulled up against the spring force and the auxiliary steering opening is opened. Semi-directly actuated valves switch from 0 bar.

Monostable

Monostable valves are valves that require a continuous control signal to switch the valve. If this control signal is lost, the valve switches back to its idle position by means of spring force.

Bistable

Bistable valves can be permanently switched over by a short control signal. Without a signal, the valve remains in its position. The valve switches back by a control signal on the other side. A separate control is therefore required for each mode.

NAMUR

Valves are available in a standard or NAMUR operated version. A NAMUR valve is a pneumatic valve with a special connection pattern of the valve's outputs. These outputs are normally ports 2 and 4 of a valve. By means of this type of connection, the valves can be mounted directly on a pneumatic actuator equipped with the same NAMUR standard. A pneumatic actuator opens and closes, for example, ball valves and butterfly valves. Thanks to this NAMUR standard, you can place the valve directly on the actuator. Hoses and couplings between the valve and actuator are therefore not necessary.

Find all your pneumatic valves at Pneuparts