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Thread: PRV's with lift indicators.
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07-12-2013, 05:57 PM #1
PRV's with lift indicators.
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.
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Re: PRV's with lift indicators.
Check this out: http://hantech.com/documents/PDF/k209d.pdf
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08-12-2013, 09:02 AM #3
Re: PRV's with lift indicators.
Balloons work quite well.
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25-12-2013, 09:51 AM #4
Re: PRV's with lift indicators.
We trap PRV outlets, put sight glasses in and fill with oil. Extremely useful if all PRVs go into a common header.
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13-02-2014, 11:40 PM #5
Re: PRV's with lift indicators.
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/Han...ochure0911.pdf Can get the optional tattletale gauge that tells how much pressure the valve saw. Bonus - Never remove the piping to change the relief.
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14-02-2014, 12:11 AM #6
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14-02-2014, 04:08 AM #7
Re: PRV's with lift indicators.
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.