Maximum safe He concentration 4 compresssion?

decoweenie · 20th November 2006, 03:14

Quote: (Originally Posted by gtzavelas)

...I have to point out that in the summer we use the compressor with VERY high ambient temperature and that at that time we had the compressor in a room with limited ventilation. The room temperature reached 40oC...

IMHO, any similar-size compressor would have problem under those conditions.

My compressor stays in the dive room in the house and has its own air conditioning unit, except in Belgium where it stays in the garage (much cooler ambient temp).

You take care of it, and it will take care of you...

Gilles · 20th November 2006, 12:57

Quote: (Originally Posted by decoweenie)

Personally, I have been pumping pure Helium for quite a number of years using the Bauer Jr-2 compressor.

I standardize my diluent to 10/50 for everything up to 92m (i.e. deepest local wreck before the sub at 120m) so I whip Helium from the J-bottle to my diluent tanks when the pressure is high enough. Then top off with air.

Once the pressure is too low (i.e. not 1/2 of max pressure required in Rebreather tanks), I whip it across to a storage source (i.e. old twinset) then feed from there into the compressor to pump into the RB tanks.

I suppose I could use the booster as well, but this is faster.

In addition, I preblend 10/50 into a storage source (i.e. again, old twinset) and just top off my Rebreather tanks thru the compressor from there.

Years ago, I was unsure about the compressor heating up before trying it. However, after seeing how a friend pump probably 100 times more Helium amount thru his Jr-2 compressor (i.e. he dives OC) at much high frequency than I do, I tried it too and haven't looked back.

Caveat, I don't run the compressor very long since the most I ever need to pump pure Helium was probably 30 mins (for the twinset). The rest of the time is shorter due to small tank size.

YMMV, so don't blame me if you blow up your compressor...

OK Thanks. I'll try not to blame you 4 blowing up the presser.

I follow your logic but even on shallower dives. A half spent dil bottle of 10/50 becomes another useful bottle of 15/30 or something near when topped with air.

Genesis · 20th November 2006, 13:10

Yeah, running a compressor in a 40C ambient environment - that's 104F - and that's the ROOM AIR temp. Ever shoot the heads with an IR thermometer? I suspect you'd be quite unhappy if you did..... and so would the manufacturer of your unit!

decoweenie · 20th November 2006, 13:18

Quote: (Originally Posted by sabgia)

I follow your logic but even on shallower dives. A half spent dil bottle of 10/50 becomes another useful bottle of 15/30 or something near when topped with air.

For clarity, I don't top off my 10/50 diluent with air. I top it off with 10/50 from my preblend storage tank.

My diluent tank is always 10/50, except for when teaching mod-1 courses, then it is air.

**wedivebc** · 20th November 2006, 14:51

I think alot of it has to do with how much. I usually use my compressor (7cfm bauer) to get the bottoms of my helium Ts. I am never pumping HE for more than 10-15 minutes at a time so I have not experienced any issues in the last 4 years.

20th November 2006, 03:14	#11 (permalink)
decoweenie Crash Test Dummy Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Feb 2005 Location: Cairo Posts: 5,510	Re: Maximum safe He concentration 4 compresssion? Quote: (Originally Posted by gtzavelas) ...I have to point out that in the summer we use the compressor with VERY high ambient temperature and that at that time we had the compressor in a room with limited ventilation. The room temperature reached 40oC... IMHO, any similar-size compressor would have problem under those conditions. My compressor stays in the dive room in the house and has its own air conditioning unit, except in Belgium where it stays in the garage (much cooler ambient temp). You take care of it, and it will take care of you... __________________ "...after a while you get bored offering advice to a bull that like to keep butting the fence with its head rather than walking through the open gate..." - Rebreather World PM
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20th November 2006, 12:57	#12 (permalink)
Gilles Worship the feminine Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: Den Haag (Netherlands) Posts: 762	Re: Maximum safe He concentration 4 compresssion? Quote: (Originally Posted by decoweenie) Personally, I have been pumping pure Helium for quite a number of years using the Bauer Jr-2 compressor. I standardize my diluent to 10/50 for everything up to 92m (i.e. deepest local wreck before the sub at 120m) so I whip Helium from the J-bottle to my diluent tanks when the pressure is high enough. Then top off with air. Once the pressure is too low (i.e. not 1/2 of max pressure required in Rebreather tanks), I whip it across to a storage source (i.e. old twinset) then feed from there into the compressor to pump into the RB tanks. I suppose I could use the booster as well, but this is faster. In addition, I preblend 10/50 into a storage source (i.e. again, old twinset) and just top off my Rebreather tanks thru the compressor from there. Years ago, I was unsure about the compressor heating up before trying it. However, after seeing how a friend pump probably 100 times more Helium amount thru his Jr-2 compressor (i.e. he dives OC) at much high frequency than I do, I tried it too and haven't looked back. Caveat, I don't run the compressor very long since the most I ever need to pump pure Helium was probably 30 mins (for the twinset). The rest of the time is shorter due to small tank size. YMMV, so don't blame me if you blow up your compressor... OK Thanks. I'll try not to blame you 4 blowing up the presser. I follow your logic but even on shallower dives. A half spent dil bottle of 10/50 becomes another useful bottle of 15/30 or something near when topped with air. __________________ Gilles http://www.dirrebreather.com Last edited by Gilles : 20th November 2006 at 13:00.
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20th November 2006, 13:10	#13 (permalink)
Genesis Bubbless Box of Death Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: Oct 2005 Location: Sunny Florida Posts: 1,394	Re: Maximum safe He concentration 4 compresssion? Yeah, running a compressor in a 40C ambient environment - that's 104F - and that's the ROOM AIR temp. Ever shoot the heads with an IR thermometer? I suspect you'd be quite unhappy if you did..... and so would the manufacturer of your unit! __________________ "A venturesome minority will always be eager to get off on their own, and no obstacles should be placed in their path; let them take risks for Godsake, let them get lost, sunburnt, stranded, drowned, eaten by bears, buried alive under avalanches - that is the right and privilege of any free American." http://www.denninger.net http://www.diversunion.org/liability.htm - Fix the Diving Cert racket
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20th November 2006, 13:18	#14 (permalink)
decoweenie Crash Test Dummy Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Feb 2005 Location: Cairo Posts: 5,510	Re: Maximum safe He concentration 4 compresssion? Quote: (Originally Posted by sabgia) I follow your logic but even on shallower dives. A half spent dil bottle of 10/50 becomes another useful bottle of 15/30 or something near when topped with air. For clarity, I don't top off my 10/50 diluent with air. I top it off with 10/50 from my preblend storage tank. My diluent tank is always 10/50, except for when teaching mod-1 courses, then it is air. __________________ "...after a while you get bored offering advice to a bull that like to keep butting the fence with its head rather than walking through the open gate..." - Rebreather World PM
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20th November 2006, 14:51	#15 (permalink)
wedivebc FIGJAM Current Rebreather/s: Megalodon Other CCR Other Rebreather/s: Not Bought Yet Inspiration Classic Sport Kiss Other CCR Join Date: Feb 2005 Location: Vancouver Island BC Canada Posts: 1,411	Re: Maximum safe He concentration 4 compresssion? I think alot of it has to do with how much. I usually use my compressor (7cfm bauer) to get the bottoms of my helium Ts. I am never pumping HE for more than 10-15 minutes at a time so I have not experienced any issues in the last 4 years. __________________ Cheers, Dave.... Man is the only animal burdened with the knowledge he will eventually die
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