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View Full Version : PRV's with lift indicators.







mlindal
07-12-2013, 06:57 PM
Does anybody know of any PRVs that have incorporated lift indicators that would fit existing PRV dimensions? See that there are add-ons but if we make any changes will have to update exisiting prv header to code, which we dont want to do at this time.

passandscore
08-12-2013, 12:23 AM
Check this out: http://hantech.com/documents/PDF/k209d.pdf

FreezerGeezer
08-12-2013, 10:02 AM
Balloons work quite well.

torque
25-12-2013, 10:51 AM
We trap PRV outlets, put sight glasses in and fill with oil. Extremely useful if all PRVs go into a common header.

mrfreezeit
14-02-2014, 12:40 AM
You cannot put a liquid in the outlet of the relief valves unless all the calculations are done to determine what effects it will do. In a valve sized for just the vessel, the back pressure will far exceed the allowable 15% in the outlet piping + back pressure created by the liquid. It will alter the capacity of the valve and possibly the pressure setting. The outlet piping is sized for vapor not oil and vapor. I know also in the USA, it is a Giant No-No to relieve oil into the environment. If you have a vent line sensor, all the oil baths will need to be replaced after a release as the oils will absorb the ammonia and mess with the sensors.
passandscore - I would not suggest rupture discs. They cost a lot and have to be changed when the relief valves are changed. They also derate the relief capacity by 10%. I have always had trouble with leakage too. Might check out this product - http://hantech.com/documents/PDF/Hansen_EZSRVBrochure0911.pdf Can get the optional tattletale gauge that tells how much pressure the valve saw. Bonus - Never remove the piping to change the relief.

RamAir95TA
14-02-2014, 01:11 AM
Balloons work quite well.

We do the same. But some of our safeties that don't have exhaust piping we keep the shipping caps over them, loosely installed.

Magoo
14-02-2014, 05:08 AM
If no external piping, electrical insulation tape or plastic caps work well, busted tape or no plastic cap then it has gone off. A squirt of oil into the exhaust also reduces the relief spring corroding, add cap or tape all good.