Monitoring lifting of Safety valves

[Bozis]

Does anyone know of a simple way to monitor if a safety valve has lifted? Most of our safety valve vent directly into a flare header making it difficult to determine if one has lifted. One way is to put a bursting disc on the discharge side of the safety valve. This solution is however expensive to retrofit on an existing plant. Any ideas ?

Thanks

 

[nagarajank]

You can try a mechanical Lift Indicator arrangement for this purpose. If the medium is at a higher temperature than atmospheric, then a thermocouple (temperature sensing element) at the outlet may serve your purpose.

 

[bljnv]

Did you really want to know if the valve has attained its full lift. Normally during the firing of safety valves, this requirement is ensured by physically measuring the lift of the stem top by using a vernier caliper.

 

[Bozis]

All I want to know is did it lift. I have an internal requirement to investigate everytime a safety valve lifts. With over 150 valves which don't have associated instruments that measure / record upstream pressure, and very limited funds I am trying to find a simple, cheap method of determining when one lifts

 

[TD2K]

Check with the major PSV vendors. I believe Consolidated (and likely others) have PSV lift indicators but I'm not sure what retrofits involve. I have seen them talked about in literature but can't remember the vendor.

 

[croxt]

Crosby has a valve indicating switch assy (VISA) that can be retro-fitted to any of their valves (OMNI, JOS-E, HCI, etc).