Directional control valves

The directional control valves divert the flow of air in different ways by means of an external control.

The parameters which characterize a valve are:

• Number of ways
• Number of positions
• Type of actuation

The number of ways is obtained by adding the number of couplings present on the valve to the number of exhausts.

The number of positions is the number of positions that the valve can assume when the control is actuated, including the rest position.

In the description of a valve, the first number represents the number of ways; the second number represents the number of positions.

For a three-way valve you must identify the function of the position at rest. It distinguishes between:

• Normally Open (NO): in the rest position the air passage is open.
• Normally Closed (NC): in the rest position the air passage is closed.

For example:

• 3/2-NO is a 3-way valve (inlet, outlet and exhaust) with 2 positions (rest and operating); in the rest position the air passage is open.
• 3/2-NC is a 3-way valve (inlet, outlet and exhaust) with 2 positions (rest and operating); in the rest position the air passage is closed.
• 5/2 is a 5-way valve (inlet, first outlet, exhaust, second outlet, exhaust) with 2 positions (rest and operating).