Pneumatic Dump Valve
Safe operation according to IEC62061 (and previously EN954/4)
To meet safety requirements you may have to dump the compressed air supply to your pneumatic cylinders or actuators, i.e. "remove all energy sources to all hazards". You may need to do this at each individual cylinder or for specific zones. This procedure and the components needed should be considered thoroughly, as the conventional dump valve offered by most manufacturers may not be suitable for today's safety culture.
You will need to dump air quickly, possible using port sizes up to 1/2"
You will need an external device to monitor that the dump valve has worked. Probably a pressure switch.
You may need to protect from accidental manual operation.
You may need to avoid "soft start" particulary soft re-start, because your system may activate output instructions before the compressed air has time to build up to sufficient pressure to operate pilot valves.
You will most likely need to have a pilot / auxiliary air supply port upstream of your dump valve.
Integral spool monitoring or position sensors may be insufficient.
You may choose an additional monitoring device to ensure pressure drop is not due to supply failure.
You may require special identifying tags and maintenance markings.
H. Kuhnke Ltd can supply an automatic pneumatic dump valve combination for safety systems. This is based on a 3/2 poppet valve, 24VDC solenoid operated, with all features assembled within a suitable enclosure.
- 1/4" Kuhnke Pneumatic Dump Valve Combination
- 1/2" Kuhnke Pneumatic Dump Valve Combination
This combination is suitable for operation using the safety channel of an ASi-Safe monitor. It is ideal for new build or easy retro-fit. For more details contact H. Kuhnke Ltd, UK. We will discuss a version to suit your Safety Integrity Level, and how to avoid specification of common cause failure.
Whichever design of pneumatic dump valve you choose we strongly recommend the function is tested, or at least de-energised, daily. This will minimise the possiblity of seals "sticking" as an indirect consequence of coil generated heat.