anybody tried 1 atm blending ?

**jmurba** · 15th April 2007, 20:14

Hi all,

I would like to blend 400 liters of trimix in a big bag injecting the o2, he and air and pumping in my 2 liters tank wjth the compressor.

god idea or bad ?

regards

jean mi

bletso · 15th April 2007, 20:48

I've been continuous blending trimix for years. I use a blending tube. Homemade of course.

Dale

**jmurba** · 15th April 2007, 21:42

Quote: (Originally Posted by bletso)

I've been continuous blending trimix for years. I use a blending tube. Homemade of course.

Dale

can u explain shortly the process ?
regards
jean mi

ntokyo · 15th April 2007, 23:09

Quote: (Originally Posted by jmurba)

Hi all,

I would like to blend 400 liters of trimix in a big bag injecting the o2, he and air and pumping in my 2 liters tank wjth the compressor.

god idea or bad ?

regards

jean mi

On the principle it is a good idea. But in practice, I see a big drawback. First is the lack of precision, as the gas within the bag may not be homogeneous and you will have eratic readings... It may be dangerous to compress an unknown gas (O2 in excess of 40%) considering that your analysis may not be precise. Imagine that your HE hose disconnect or He bank is empty and your O2 % will immediately raise over 40%.... I am not certain how you plan to inject air inside, depending of the method it may not be very accurate.... I have a small compressor and the inspiration is varying along a tank filling. You need to have a way to tune the air, o2 or He entry along the blending.
I would rather avoid compressing O2 if a proper "mixing" is not made before.

I suggest to use this method for Helium only. As for O2, do it separately by partial pressure (lyre) with a O2 clean tank. Or you can buy a Continious Blending mixer, that will mix properly the gas before entering the compressor. Make sure to have an analyser before the compressor to do not exceed the 40%. To buy a mixer you can do it in France at Bigata.fr or underwaterexplorers in Bordeaux. Buy it in Europe, in US it is incredibly expensive as a company registered a patent...

ntokyo · 15th April 2007, 23:11

Quote: (Originally Posted by jmurba)

can u explain shortly the process ?
regards
jean mi

Take a look at plongeesout.com or buy the book of Jacques Vettier on Trimix, everything is verey nicely explained. Bag techinique is explained.

Dave & Sandy · 15th April 2007, 23:55

We have been pumping Helium through our compressor using a continuous flow method for a couple of years.

Our intake to our compressor sucks in air through the normal snorkel and Helium from a G via an industrial regulator (Co2 & Argon) attached to the G. A hose runs from the G/indutrial reg to the air intake. We set the flow rate of Helium on the industrial reg to say 15L/min and control the quantity of Helium by time (stop watch).

A few simple calculations are required to work out how much Helium needs to go in over what time period. O2 is cascaded first from a G.

This method is simple (no fiddeling with bags), cost effective, ($100 Au for an industrial reg), you can extract every last bit of helium from the G, you don't stuff your compressor because you are pumping Helium and air simultaneously, no need to start/stop your compressor, versatile as if you go away you can take a G and fill in the field, dam accurate (+-0.5%), never have to dump a used mix.

**jmurba** · 16th April 2007, 06:56

Quote: (Originally Posted by ntokyo)

On the principle it is a good idea. But in practice, I see a big drawback. First is the lack of precision, as the gas within the bag may not be homogeneous and you will have eratic readings... It may be dangerous to compress an unknown gas (O2 in excess of 40%) considering that your analysis may not be precise. Imagine that your HE hose disconnect or He bank is empty and your O2 % will immediately raise over 40%.... I am not certain how you plan to inject air inside, depending of the method it may not be very accurate.... I have a small compressor and the inspiration is varying along a tank filling. You need to have a way to tune the air, o2 or He entry along the blending.
I would rather avoid compressing O2 if a proper "mixing" is not made before.

I suggest to use this method for Helium only. As for O2, do it separately by partial pressure (lyre) with a O2 clean tank. Or you can buy a Continious Blending mixer, that will mix properly the gas before entering the compressor. Make sure to have an analyser before the compressor to do not exceed the 40%. To buy a mixer you can do it in France at Bigata.fr or underwaterexplorers in Bordeaux. Buy it in Europe, in US it is incredibly expensive as a company registered a patent...

Hello,
my problem is not to blend trimix, as a matter of fact it is not difficult to do it using the various classic methods .
my problem is to be able to top up my 2 liters tanks...
my idea was to do it in a bag before starting to pump the mix .
I wanted to intake a certain amount of air, and then a certain amount of helium (an heliair) and finaly add a little bit of O2 to go back to a normoxic mix as I dive shallow (50/60m).
but you point out some difficulties... as a matter of fact it will be difficult to know how much of every gas I have intaken in the bag, if I transfer helium from my b50 bank in a 400 liter bag, pressure drop in the bank will to small to mesure the amount of helium transfered..... well bad idea...
forget about that (((-:

regards

jean mi

**jmurba** · 16th April 2007, 06:58

Quote: (Originally Posted by Dave & Sandy)

We have been pumping Helium through our compressor using a continuous flow method for a couple of years.

Our intake to our compressor sucks in air through the normal snorkel and Helium from a G via an industrial regulator (Co2 & Argon) attached to the G. A hose runs from the G/indutrial reg to the air intake. We set the flow rate of Helium on the industrial reg to say 15L/min and control the quantity of Helium by time (stop watch).

A few simple calculations are required to work out how much Helium needs to go in over what time period. O2 is cascaded first from a G.

This method is simple (no fiddeling with bags), cost effective, ($100 Au for an industrial reg), you can extract every last bit of helium from the G, you don't stuff your compressor because you are pumping Helium and air simultaneously, no need to start/stop your compressor, versatile as if you go away you can take a G and fill in the field, dam accurate (+-0.5%), never have to dump a used mix.

it seems good but not a good solution to be able to top up the tanks...i definitely need an helium analyzer (((-:

JonORunde · 16th April 2007, 07:16

The oxygen-hacker -book
Vance Harlow's OXYGEN HACKER'S COMPANION From AIrspeed Press
has some nice ideas about continous mixing trimix.
You do not need an He-analyzer, but with two O2analyzers, and some math, you can measure the mix correctly through a mixing-stick, that you can build yourself.
This will enable you to top off your mix-bottles.
You can also topp off with
1. bagging pure He in your bag, through the compressor, then
2. top off with 40% -that you continous-blend with a simpler mixing-stick, and
3. a little air on the top.

This is what I do... -when not using the booster

jon o

Marc T · 16th April 2007, 08:06

Quote: (Originally Posted by jmurba)

it seems good but not a good solution to be able to top up the tanks...i definitely need an helium analyzer (((-:

Hi Jean-Michel,

A solution is to always blend trimix from a fixed nitrox 30 for example ( first blend ) in which I add the helium. ( for me, all is done by continus blending on compressor )
So watether the way you use to blend initialy your gas ( nitrox then heliox ) and after that eventually top up your tank you alway have a blend of two part which are NX 30 and pure He.
So the computations are the same as if it was heliair, except air is replaced by NX30.
So what?

Ho hum read your post about hydrogom, fortunatly Ive not contact them for spare parts as whe have not the same system

, ive the old one!

Cheers

Marc

15th April 2007, 20:14	#1 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 861	anybody tried 1 atm blending ? Hi all, I would like to blend 400 liters of trimix in a big bag injecting the o2, he and air and pumping in my 2 liters tank wjth the compressor. god idea or bad ? regards jean mi __________________ when will I be able to think about something else then spending hours underwater, when will I be normal ? http://web.mac.com/jmurba/Site_2/home.html http://web.mac.com/jmurba/Site_3/home.html
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15th April 2007, 20:48	#2 (permalink)
bletso An independent diver. Current Rebreather/s: Dolphin Home Build Other Rebreather/s: Dolphin Home Build Join Date: May 2006 Location: Louisville, KY, USA Posts: 256	Re: anybody tried 1 atm blending ? I've been continuous blending trimix for years. I use a blending tube. Homemade of course. Dale
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15th April 2007, 21:42	#3 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 861	Re: anybody tried 1 atm blending ? Quote: (Originally Posted by bletso) I've been continuous blending trimix for years. I use a blending tube. Homemade of course. Dale can u explain shortly the process ? regards jean mi __________________ when will I be able to think about something else then spending hours underwater, when will I be normal ? http://web.mac.com/jmurba/Site_2/home.html http://web.mac.com/jmurba/Site_3/home.html
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15th April 2007, 23:09	#4 (permalink)
ntokyo New Member Current Rebreather/s: rEvo Other Rebreather/s: rEvo Join Date: Dec 2006 Location: Tokyo, Japan Posts: 90	Re: anybody tried 1 atm blending ? Quote: (Originally Posted by jmurba) Hi all, I would like to blend 400 liters of trimix in a big bag injecting the o2, he and air and pumping in my 2 liters tank wjth the compressor. god idea or bad ? regards jean mi On the principle it is a good idea. But in practice, I see a big drawback. First is the lack of precision, as the gas within the bag may not be homogeneous and you will have eratic readings... It may be dangerous to compress an unknown gas (O2 in excess of 40%) considering that your analysis may not be precise. Imagine that your HE hose disconnect or He bank is empty and your O2 % will immediately raise over 40%.... I am not certain how you plan to inject air inside, depending of the method it may not be very accurate.... I have a small compressor and the inspiration is varying along a tank filling. You need to have a way to tune the air, o2 or He entry along the blending. I would rather avoid compressing O2 if a proper "mixing" is not made before. I suggest to use this method for Helium only. As for O2, do it separately by partial pressure (lyre) with a O2 clean tank. Or you can buy a Continious Blending mixer, that will mix properly the gas before entering the compressor. Make sure to have an analyser before the compressor to do not exceed the 40%. To buy a mixer you can do it in France at Bigata.fr or underwaterexplorers in Bordeaux. Buy it in Europe, in US it is incredibly expensive as a company registered a patent...
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15th April 2007, 23:11	#5 (permalink)
ntokyo New Member Current Rebreather/s: rEvo Other Rebreather/s: rEvo Join Date: Dec 2006 Location: Tokyo, Japan Posts: 90	Re: anybody tried 1 atm blending ? Quote: (Originally Posted by jmurba) can u explain shortly the process ? regards jean mi Take a look at plongeesout.com or buy the book of Jacques Vettier on Trimix, everything is verey nicely explained. Bag techinique is explained.
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15th April 2007, 23:55	#6 (permalink)
Dave & Sandy New Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Jun 2006 Location: Melbourne, Australia Posts: 99	Re: anybody tried 1 atm blending ? We have been pumping Helium through our compressor using a continuous flow method for a couple of years. Our intake to our compressor sucks in air through the normal snorkel and Helium from a G via an industrial regulator (Co2 & Argon) attached to the G. A hose runs from the G/indutrial reg to the air intake. We set the flow rate of Helium on the industrial reg to say 15L/min and control the quantity of Helium by time (stop watch). A few simple calculations are required to work out how much Helium needs to go in over what time period. O2 is cascaded first from a G. This method is simple (no fiddeling with bags), cost effective, ($100 Au for an industrial reg), you can extract every last bit of helium from the G, you don't stuff your compressor because you are pumping Helium and air simultaneously, no need to start/stop your compressor, versatile as if you go away you can take a G and fill in the field, dam accurate (+-0.5%), never have to dump a used mix. __________________ Cheers, Dave & Sandy Atvar shows Dave & Sandy testing their new habitat 101 and home build RBMK69's Last edited by Dave & Sandy : 15th April 2007 at 23:56. Reason: spullin
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16th April 2007, 06:56	#7 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 861	Re: anybody tried 1 atm blending ? Quote: (Originally Posted by ntokyo) On the principle it is a good idea. But in practice, I see a big drawback. First is the lack of precision, as the gas within the bag may not be homogeneous and you will have eratic readings... It may be dangerous to compress an unknown gas (O2 in excess of 40%) considering that your analysis may not be precise. Imagine that your HE hose disconnect or He bank is empty and your O2 % will immediately raise over 40%.... I am not certain how you plan to inject air inside, depending of the method it may not be very accurate.... I have a small compressor and the inspiration is varying along a tank filling. You need to have a way to tune the air, o2 or He entry along the blending. I would rather avoid compressing O2 if a proper "mixing" is not made before. I suggest to use this method for Helium only. As for O2, do it separately by partial pressure (lyre) with a O2 clean tank. Or you can buy a Continious Blending mixer, that will mix properly the gas before entering the compressor. Make sure to have an analyser before the compressor to do not exceed the 40%. To buy a mixer you can do it in France at Bigata.fr or underwaterexplorers in Bordeaux. Buy it in Europe, in US it is incredibly expensive as a company registered a patent... Hello, my problem is not to blend trimix, as a matter of fact it is not difficult to do it using the various classic methods . my problem is to be able to top up my 2 liters tanks... my idea was to do it in a bag before starting to pump the mix . I wanted to intake a certain amount of air, and then a certain amount of helium (an heliair) and finaly add a little bit of O2 to go back to a normoxic mix as I dive shallow (50/60m). but you point out some difficulties... as a matter of fact it will be difficult to know how much of every gas I have intaken in the bag, if I transfer helium from my b50 bank in a 400 liter bag, pressure drop in the bank will to small to mesure the amount of helium transfered..... well bad idea... forget about that (((-: regards jean mi __________________ when will I be able to think about something else then spending hours underwater, when will I be normal ? http://web.mac.com/jmurba/Site_2/home.html http://web.mac.com/jmurba/Site_3/home.html
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16th April 2007, 06:58	#8 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 861	Re: anybody tried 1 atm blending ? Quote: (Originally Posted by Dave & Sandy) We have been pumping Helium through our compressor using a continuous flow method for a couple of years. Our intake to our compressor sucks in air through the normal snorkel and Helium from a G via an industrial regulator (Co2 & Argon) attached to the G. A hose runs from the G/indutrial reg to the air intake. We set the flow rate of Helium on the industrial reg to say 15L/min and control the quantity of Helium by time (stop watch). A few simple calculations are required to work out how much Helium needs to go in over what time period. O2 is cascaded first from a G. This method is simple (no fiddeling with bags), cost effective, ($100 Au for an industrial reg), you can extract every last bit of helium from the G, you don't stuff your compressor because you are pumping Helium and air simultaneously, no need to start/stop your compressor, versatile as if you go away you can take a G and fill in the field, dam accurate (+-0.5%), never have to dump a used mix. it seems good but not a good solution to be able to top up the tanks...i definitely need an helium analyzer (((-: __________________ when will I be able to think about something else then spending hours underwater, when will I be normal ? http://web.mac.com/jmurba/Site_2/home.html http://web.mac.com/jmurba/Site_3/home.html
(Offline)

16th April 2007, 07:16	#9 (permalink)
JonORunde New Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Dec 2005 Location: Norway Posts: 88	Re: anybody tried 1 atm blending ? The oxygen-hacker -book Vance Harlow's OXYGEN HACKER'S COMPANION From AIrspeed Press has some nice ideas about continous mixing trimix. You do not need an He-analyzer, but with two O2analyzers, and some math, you can measure the mix correctly through a mixing-stick, that you can build yourself. This will enable you to top off your mix-bottles. You can also topp off with 1. bagging pure He in your bag, through the compressor, then 2. top off with 40% -that you continous-blend with a simpler mixing-stick, and 3. a little air on the top. This is what I do... -when not using the booster jon o
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16th April 2007, 08:06	#10 (permalink)
Marc T hell is in the details Current Rebreather/s: RB80 / Clone Home Build Other Rebreather/s: Not Bought Yet RB80 / Clone Home Build Join Date: Sep 2005 Location: FRANCE Carcassonne Posts: 485	Re: anybody tried 1 atm blending ? Quote: (Originally Posted by jmurba) it seems good but not a good solution to be able to top up the tanks...i definitely need an helium analyzer (((-: Hi Jean-Michel, A solution is to always blend trimix from a fixed nitrox 30 for example ( first blend ) in which I add the helium. ( for me, all is done by continus blending on compressor ) So watether the way you use to blend initialy your gas ( nitrox then heliox ) and after that eventually top up your tank you alway have a blend of two part which are NX 30 and pure He. So the computations are the same as if it was heliair, except air is replaced by NX30. So what? Ho hum read your post about hydrogom, fortunatly Ive not contact them for spare parts as whe have not the same system , ive the old one! Cheers Marc
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