2 replies to this topic

[Epoche]

I have a few questions pertaining to relief valves and their nameplates.

 

1) Found a conventional relief valve that had a set pressure change. On the original nameplate, the following items were crossed out: set pressure, capacity, and CDTP. There is constant superimposed back pressure (greater than 10% of set pressure) in the discharge line, so the CDTP is different than the set pressure. There was a secondary tag attached to the valve that listed the new set pressure and capacity, but did not have the new CDTP listed. Should the secondary valve state the CDTP?

 

2) Found a relief valve with a missing nameplate. It can't be 100% verified; the valve should be replaced?

 

3) Found a valve that looks like the original nameplate fell off and a new one was put on (has service provider's name listed on it instead of the manufacturer's). The nameplate is no longer code stamped (UV and NB); the valve should be replaced?

 

4) Sort of related, how does the NBIC "VR" program play into valve servicing? My understanding is that if any machining or part replacement needs to be done, a tag stamped VR needs to be present? For example, my question 1), if a set pressure change was performed and then a CDTP correction needed to be performed, would this then need a VR stamp? My thinking is that the spring would have to be replaced.

 

I appreciate your help.

[ValveBoy]

Epoche, i have been servicing safety valves for a long time. I work in a "VR" stamp holder shop and the answers below are what we would do if we were asked to repair the valves you described.

 

1. Yes, the "repair nameplate " must show the new set pressure, capacity, bp and cdtp and any other information that has changed from the OEM nameplate such as a conversion which changes the model number.

2. Yes, we would not repair that valve, we would recommend replacing.

3. we occasionally install a "duplicate nameplate" if the original is missing or worn out. The duplicate nameplate we use has all the information from the OEM nameplate except the asme code stamp and nb stamp, we do however have to stamp on the nameplate "asme code section VIII" for example. Also the nameplate must state "duplicate nameplate".

4. the National Board "VR" program is a quality program for servicing safety/relief valves.

4a. yes, we would "VR" stamp the valve because we would have checked all the components of the valve, spring range, etc. to assure it performed as intended. We would have replaced the spring if it fell out of the range for the new set pressure.

[Epoche]

That's awesome information, thank you!