nitrogen vs. ***** r22 vs. ???

[Eddi]

good day ya all !

i'm new at this forum, but i was following threads for awhile now ..

and now, i have a serious question, hope someone could help !


in my company, we are using ***** r22 to detect leakage in condenser soils, pressurized up to 100 psi. then we add nitrogen gas to increase the net pressure up to 450 psi.

then we sealed it, and use ***** r22 detector to investigate for leaks with sensitivity of 0.01 oz/yr.


now, i'm thinking of replace the current system by only using nitrogen gas, which we already generate in house, as testing gas, and we also might install some recovery system to re-use the nitrogen number of times. where we also going to test some units at 650 psi.

my question is, is there a nitrogen detector that can detect leaked nitrogen gas of sensitives 0.01 oz/yr ?

if not, what would be an alternative gas for testing, and what is the best detection system for the alternative gas ?


thanx and happy new year to ya all !

[Eddi]

condenser coils * << spelling mistake

[monkey spanners]

Hi Eddi,

There is a lot of nitrogen in the air so a detector won't be able to tell the difference between background nitrogen and any that may have leaked from the system being tested.

I believe a lot of manufacturers test with nitrogen with a trace of helium (it is available ready mixed here) as helium is not generally found in the air and has very small molecules so is good at finding very small leaks. Special helium detectors are needed.

Jon

[chilliwilly]

I have a Dtec select detector and that picks up Nitrogen. As I only work on smaller refrigeraton systems these days with short pipe runs (less than 20 meters). I can always use leak detection spray if the leak isn't local or doesn't trace on the detector. Over here in Europe its illegal to vent ***** into the atmosphere, or even top up a leaking system with *****. Do you have a similar EPA/F gas regs implemented in Saudi?

edit

Or there's always the UV tracing die, I never used though so I don't know if its any good or not.

[Eddi]

i liked your idea ..

and i missed that point of background nitrogen .. it really matters

anyhow, can you provide me with more detail about the nitrogen-helium gas .. like the vendor or pricing or even if you have tried it and you have some more details

thanx in advanced

[Eddi]

I have a Dtec select detector and that picks up Nitrogen. As I only work on smaller refrigeraton systems these days with short pipe runs (less than 20 meters). I can always use leak detection spray if the leak isn't local or doesn't trace on the detector. Over here in Europe its illegal to vent ***** into the atmosphere, or even top up a leaking system with *****. Do you have a similar EPA/F gas regs implemented in Saudi?

edit

Or there's always the UV tracing die, I never used though so I don't know if its any good or not.

thanx for your reply

so far, no regulation has taken place, but soon it will be.

i will check the UV, knowing though it's not the best solution for the company. thanx anyway

[frank]

One other option to consider is using an ultrasonic leak detector. No need to use a trace gas and will work with OFN

http://www.inficonultrasonicleakdete...kdetector.html

http://www.refrigeration-engineer.co...ght=ultrasonic

[chemi-cool]

You can add a small amount of Helium to the Nitrogen.
helium is easier to detect and you can detect smaller leaks.

[Brian_UK]

BOC Helium/OFN mix...
http://www.boconline.co.uk/products/...tion_gases.asp

[Eddi]

thank you all

actually i started working in your ideas, specially the nitrogen-helium mix and the UV.

but so far the best sensitivity UV offers is 0.1 oz/yr, while we strictly require 0.01 oz/yr for best quality.

thus, i'm thinking more about the traced gas mixture.


thanx for your help guys

i'll dig more and hopefully i'll find a way.

[lawrence1]

Why so high test pressures,,,,are these CO2 systems?
450 psi and 650 psi oh my god.

[Eddi]

they're chiller condenser coils and evaporators

the testing for cond. coil is done at 450 psi, evaporator at 350 psi.

the 650 psi is for upcoming bigger units.

and as you know, testing should be conducted at the operating limits. it's not just an exaggeration of higher standards.

[SkyWalker]

Safe handling of refrigerants states that pressure testing shall be:-

for Strength 1.1 - 1.43 MWP for a minimum of 15 mins
For leak detection 1 x MWP for minimum 60 mins

Mwp = 55c Air cooled high side, 43c Water cooled high side and 32c low side

I use 1.1 for strength then leak test at 1 x MWP

[Quality]

Safe handling of refrigerants states that pressure testing shall be:-

for Strength 1.1 - 1.43 MWP for a minimum of 15 mins
For leak detection 1 x MWP for minimum 60 mins

Mwp = 55c Air cooled high side, 43c Water cooled high side and 32c low side



I use 1.1 for strength then leak test at 1 x MWP

It s BS EN 378 2008 which states that not safe handling of refrigerants

[Brian_UK]

Also, if within the EU then using refrigerant for leak testing is illegal.

[Tesla]

Eddi
In the old days when we couldn't find a leak on a coil but knew there was one we would remove the coil blow it up with nitro and submerse it into a bucket of water and see bubbles where the leaks were. But I'm not sure what rate of detection this method would give. Just a thought but I think the Helium and ultrasonic ideas are better.

[SkyWalker]

It s BS EN 378 2008 which states that not safe handling of refrigerants

fair enough, u know what i mean its doing it correctly thats important

[hyperion]

There is also the nitrogen/hydrogen mix that is available. You will need a special leak detector and normally do not need to test at such high pressures to find a leak. It is quite expensive if used in large quantities and may not suit your manufacturing test pressures.

[Quality]

fair enough, u know what i mean its doing it correctly thats important

Yeh I know what ya mean, I posted so that everyone else does.

[tajger]

Use nitrogen and submerge the condenser in a pool.