General

The pneumatic time delay valves from SFS are used in circuits and systems for the precise control of pneumatic signals and combine the function of a 3/2-way valve and a time delay unit.

The delay time can be set continuously from 0-30s with a repeat accuracy of +-2%. After the set time has elapsed, the 3/2-way valve switches and opens or closes the output for the compressed air. This means that the SFS time delay valve can be used both as a 3/2-way NC (normally closed) valve and as a 3/2 way NO (normally open) valve.

ATEX

As the time delay valve operates purely pneumatically and does not require a power connection, it does not fall under the ATEX directive according to the ignition risk assessment. This means that this valve can also be used in potentially explosive atmospheres without any problems.

Function

The control air at port X flows through the adjustable fine throttle (0-30s) into a volume in the time delay valve. As soon as the pressure in the volume exceeds a defined value, the 3/2-way valve switches over.

If the control pressure is removed again (vented), the valve returns to its initial state and is available for the next control task.

When pressure input a is used, the time delay valve has a positive output A. If pressure input b is used, the valve has a negative output A.

Increasing the setting time with additional volume

If an extension of the setting range of 30 s is required (e.g. 60 s), an additional volume (additional tank) can be connected to the valve via an M5 connection.