Swing Check Position?

[Budro]

I have a 1500# steam swing check valve with no external indication of the open or close position of the check. Does anybody know if there is an external/clamp on device that can determine the position of the check without modifying the valve (ASME Boiler valve)?

 

[zdas04]

To determine if it is moving you can use a stethescope. If you have a good ear you should also be able to differentiate flow from no-flow. Beyond that the only ongoing indicator I can think of is a strap-on ultrasonic flow-measurement device.

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Cockroach]

Depending on the make of the check valve, for years I have simply scribed a line on the clapper shaft relative to an external reference point to show "CLOSED". Obviously when the valve is OPEN, the line is misaligned.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[Budro]

I wish this was the case, but the swing check shaft is completely enclosed in the body of the valve. We also need to the position prior to any flow/process moving in the pipe. The only thing I can think of is X-ray.

Jeff

 

[MikeHalloran]

If you applied an alternating magnetic field across the valve, parallel to the check shaft, say by means of a C- shaped armature with pole pieces near the valve seat, you might be able to measure, say with a linear output Hall effect device on one pole, a change in the valve's magnetic impedance (reluctance?) depending on whether the poppet was in the seat or not.

I'd expect a small signal, and you'll probably need to also measure the temperature so you can compensate the LOHED.

-Mike-