anybody tried 1 atm blending ?

Gilles · 17th April 2007, 04:57

Quote: (Originally Posted by jmurba)

Hi gilles,

My problerm is not to find a way to blend trimix , I learnt that with Iantd ten years ago, my problem is to find a simple way to top up my trimix dil tanks without having to empty it first.
with no helium analyzer one can top up using partial pressure methode, but only one time, after on top up the mix error is not acceptable any more.
some may top up many times but I don't cause I do what I was educated to do....
I had considered that blendig the necessary trimix to top up in a bag at 1 atm would have been a way to minimized the error givent that there is no compressibility rate problem and that I could have very easily merure fo2 in the bag.. but it does not seems to be as easy as I hoped (((-:

so blending using a continuous methode is mabye a solution to top up tanks....but how to do it ?

a continuous blending makes it possible to top with a premix gas without adding first nitrox and after helium generating errors.

Dales says he is used to do it , but I don't see how to do.
what whould I inject in the mixed, in what order ?

I thougth it was possible in using too mixers ate the same time, one nitrox mixer with and o2 sensor , and a second to add helium in the nitrox higer contiuously blended, but is seems to be very difficult

no solution

regards

jean mi

Jean Michel;

As long as you are dealing with only Helium and air (or only one type of Nitrox), you can always determine what your He content is by only measuring your O2.

The attached table can be used, providing you are topping up with either air or Helium. Just look up what your O2 is, and the corresponding He concentration will be there.

I can create another table if you'd like to use a constant Nitrox of some kind.

J'espere a votre service.

rdmmdr · 17th April 2007, 05:15

What i dont understand is, if you felt confident to make the mix the first time and not die. why not just make the mix again and transfill with a booster. it sounds like it is time to get a helium meter.
rick

**jmurba** · 17th April 2007, 07:42

Quote: (Originally Posted by Gilles)

Jean Michel;

As long as you are dealing with only Helium and air (or only one type of Nitrox), you can always determine what your He content is by only measuring your O2.

The attached table can be used, providing you are topping up with either air or Helium. Just look up what your O2 is, and the corresponding He concentration will be there.

I can create another table if you'd like to use a constant Nitrox of some kind.

J'espere a votre service.

Hi ,

ok you've just given me the solution

... but I think I have the solution now... I will first bend a nitrox in a tank, then I will use and expansion bag, this bag will be connected to the the only stick, I will inject helium in the stick to blend the trimix.... knowing accuratly the nitrox fo2 that won't drift as it could with a first nitrox stick...
that way I wil be sure of the He fraction and will be able to top my tanks...
but I definitly need an helium analyze (((-:

great....

regards

jean mi

**jmurba** · 17th April 2007, 07:44

Quote: (Originally Posted by rdmmdr)

What i dont understand is, if you felt confident to make the mix the first time and not die. why not just make the mix again and transfill with a booster. it sounds like it is time to get a helium meter.
rick

heu well ...true(((-: for the 2 points (((-:

Gilles · 17th April 2007, 08:51

Quote: (Originally Posted by jmurba)

Hi ,

ok you've just given me the solution

... but I think I have the solution now... I will first bend a nitrox in a tank, then I will use and expansion bag, this bag will be connected to the the only stick, I will inject helium in the stick to blend the trimix.... knowing accuratly the nitrox fo2 that won't drift as it could with a first nitrox stick...
that way I wil be sure of the He fraction and will be able to top my tanks...
but I definitly need an helium analyze (((-:

great....

regards

jean mi

Jean Michel;

Providing you are using a big storage of Nitrox, and you are not re-mixing or contaminating it with air using the above method, you should not really need an He analyzer.

Good luck anyway.
G

**jmurba** · 17th April 2007, 14:07

Quote: (Originally Posted by Gilles)

Jean Michel;

Providing you are using a big storage of Nitrox, and you are not re-mixing or contaminating it with air using the above method, you should not really need an He analyzer.

Good luck anyway.
G

hem....
why a big nitrox bank ?
I only usualy blend 200 litres of trimix .
as for the air contamination as a matter of fact I think I will have to pay attention to this...it is maybye worth to install an o2 analyzer in the expansion bag on on the hose going from the bag to the intake of the stick...well I see thing clearer now tanks of all replies...
regards
jean mi

Gilles · 17th April 2007, 23:41

Quote: (Originally Posted by jmurba)

hem....
why a big nitrox bank ?
I only usualy blend 200 litres of trimix .
as for the air contamination as a matter of fact I think I will have to pay attention to this...it is maybye worth to install an o2 analyzer in the expansion bag on on the hose going from the bag to the intake of the stick...well I see thing clearer now tanks of all replies...
regards
jean mi

I replied a bit too quickly (on company time). What I mean is that if you are topping up Rebreather tanks with only Helium, and/or a certain nitrox (that never changes as a result of topping up/remixing the nitrox only storage tank). You can always determine your He and N2 concentration by measuring only the O2. You would need a special reference table (the one above is valid for Heliair only).

In order for this to work, you have to be very strict about always having the same Nitrox.

If you are ok with hypoxic Heliair mixes (as I am), it is more practical. Providing your compressor is sucking clean air, it'll always be 20.9%.

G

**jmurba** · 18th April 2007, 07:06

Quote: (Originally Posted by Gilles)

I replied a bit too quickly (on company time). What I mean is that if you are topping up Rebreather tanks with only Helium, and/or a certain nitrox (that never changes as a result of topping up/remixing the nitrox only storage tank). You can always determine your He and N2 concentration by measuring only the O2. You would need a special reference table (the one above is valid for Heliair only).

In order for this to work, you have to be very strict about always having the same Nitrox.

If you are ok with hypoxic Heliair mixes (as I am), it is more practical. Providing your compressor is sucking clean air, it'll always be 20.9%.

G

Well,
it is not easy to blend trimix...as a matter of fact heliair would be a solution, after all we have ccr's and can intake as mutch o2 as we need in the circuit....
mabye would it be the better solution....an other solution would be to add a little bit of o2 and top with heliair.....many solutions, no perfect solution....
I must admit that I m a little bit lost...
thanks anyway..
regards
jean mi

Gilles · 18th April 2007, 09:21

Quote: (Originally Posted by jmurba)

Well,
....an other solution would be to add a little bit of o2 and top with heliair.....many solutions, no perfect solution....
I must admit that I m a little bit lost...
thanks anyway..
regards
jean mi

Jean Michel;

Edited.

Anytime you begin adding O2 to Heliair, it becomes Trimix, and then you'll start needing an He analyzer when you top up.

Whenever you have 3 quantities (such as O2, N2, and He), as long as you know 2 of them, you can always determine the 3rd.

So how do we keep track of the 2 quantities with a single measurement? By always using the same 2-component gas (air or constant nitrox, in this case EAN32).

Attached is a table you can use to track your mix, providing you are only topping up with He, or EAN32. You can make any Trimix using any other EAN type (but a new table is needed for ech type).

When topping up, as long as you are using only He and EAN32, you do not need an He analyzer and will always know your He fraction.

Depending on what remains in the tank, you boost the additional amount of He you want (or none at all). By only measuring the O2, you determine the He by using the attached table (providing your EAN32 is EAN32). Go to the measured O2 level of left column, moving to the right, you get he fractions of He, EAN32, and N2 respectively.

I wouldn't want to encourage Heliair use to anyone who isn't aware of the hazard of hypoxic dil. There is good advice in this forum about not using hypoxic when not needed. It is a risk I calculate as acceptable for myself.

So, instead of spending 700-800 Euro on an analyzer, you only need to click a green blob for your Rebreather World colleague.

Voila.

**jmurba** · 18th April 2007, 14:25

Quote: (Originally Posted by Gilles)

Jean Michel;

Edited.

Anytime you begin adding O2 to Heliair, it becomes Trimix, and then you'll start needing an He analyzer when you top up.

Whenever you have 3 quantities (such as O2, N2, and He), as long as you know 2 of them, you can always determine the 3rd.

So how do we keep track of the 2 quantities with a single measurement? By always using the same 2-component gas (air or constant nitrox, in this case EAN32).

Attached is a table you can use to track your mix, providing you are only topping up with He, or EAN32. You can make any Trimix using any other EAN type (but a new table is needed for ech type).

When topping up, as long as you are using only He and EAN32, you do not need an He analyzer and will always know your He fraction.

Depending on what remains in the tank, you boost the additional amount of He you want (or none at all). By only measuring the O2, you determine the He by using the attached table (providing your EAN32 is EAN32). Go to the measured O2 level of left column, moving to the right, you get he fractions of He, EAN32, and N2 respectively.

I wouldn't want to encourage Heliair use to anyone who isn't aware of the hazard of hypoxic dil. There is good advice in this forum about not using hypoxic when not needed. It is a risk I calculate as acceptable for myself.

So, instead of spending 700-800 Euro on an analyzer, you only need to click a green blob for your Rebreather World colleague.

Voila.

Hi Gilles,

thanks for spending the time to explain me all of that, after this disscussion I have now a mutch better view of the problem.
I think that even if it is a little bit dear I will buy an he analyzer , to be more confortable but I agree with you on the point that it is possible to do without using the methodes we were discussing.
however I decided to fine down the problem, I am going blend my weak trimix in a 30 liters twin tank using the old partial pressure method with the help of my booster if necessary, then I will fill my dil 2 liters, and after every dive I will top them up using the compressor or the booster to transfer....4000 liters of trimix on 2 2 liter tanks usualy on emptied by half will give me 10 dives...ten weeks more given that sometime meteo sends you to the pub ((-:.
as you said I don't want an heliair, I am a shalow diver not willing to use hypoxic dils.
I've semiclosely rebreathed my dil on electronic breakdowns and I was happy to get a descent fo2 in the mix not to **** my deco .
regards
jean mi

17th April 2007, 05:15	#22 (permalink)
rdmmdr designer of death Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Mar 2006 Location: kerman,california Posts: 372	Re: anybody tried 1 atm blending ? What i dont understand is, if you felt confident to make the mix the first time and not die. why not just make the mix again and transfill with a booster. it sounds like it is time to get a helium meter. rick
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17th April 2007, 07:42	#23 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 718	Re: anybody tried 1 atm blending ? Quote: (Originally Posted by Gilles) Jean Michel; As long as you are dealing with only Helium and air (or only one type of Nitrox), you can always determine what your He content is by only measuring your O2. The attached table can be used, providing you are topping up with either air or Helium. Just look up what your O2 is, and the corresponding He concentration will be there. I can create another table if you'd like to use a constant Nitrox of some kind. J'espere a votre service. Hi , ok you've just given me the solution ... but I think I have the solution now... I will first bend a nitrox in a tank, then I will use and expansion bag, this bag will be connected to the the only stick, I will inject helium in the stick to blend the trimix.... knowing accuratly the nitrox fo2 that won't drift as it could with a first nitrox stick... that way I wil be sure of the He fraction and will be able to top my tanks... but I definitly need an helium analyze (((-: great.... 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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17th April 2007, 07:44	#24 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 718	Re: anybody tried 1 atm blending ? Quote: (Originally Posted by rdmmdr) What i dont understand is, if you felt confident to make the mix the first time and not die. why not just make the mix again and transfill with a booster. it sounds like it is time to get a helium meter. rick heu well ...true(((-: for the 2 points (((-: __________________ 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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17th April 2007, 08:51	#25 (permalink)
Gilles Worship the feminine Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: Den Haag (Netherlands) Posts: 762	Re: anybody tried 1 atm blending ? Quote: (Originally Posted by jmurba) Hi , ok you've just given me the solution ... but I think I have the solution now... I will first bend a nitrox in a tank, then I will use and expansion bag, this bag will be connected to the the only stick, I will inject helium in the stick to blend the trimix.... knowing accuratly the nitrox fo2 that won't drift as it could with a first nitrox stick... that way I wil be sure of the He fraction and will be able to top my tanks... but I definitly need an helium analyze (((-: great.... regards jean mi Jean Michel; Providing you are using a big storage of Nitrox, and you are not re-mixing or contaminating it with air using the above method, you should not really need an He analyzer. Good luck anyway. G __________________ Gilles http://www.dirrebreather.com
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17th April 2007, 14:07	#26 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 718	Re: anybody tried 1 atm blending ? Quote: (Originally Posted by Gilles) Jean Michel; Providing you are using a big storage of Nitrox, and you are not re-mixing or contaminating it with air using the above method, you should not really need an He analyzer. Good luck anyway. G hem.... why a big nitrox bank ? I only usualy blend 200 litres of trimix . as for the air contamination as a matter of fact I think I will have to pay attention to this...it is maybye worth to install an o2 analyzer in the expansion bag on on the hose going from the bag to the intake of the stick...well I see thing clearer now tanks of all replies... 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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17th April 2007, 23:41	#27 (permalink)
Gilles Worship the feminine Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: Den Haag (Netherlands) Posts: 762	Re: anybody tried 1 atm blending ? Quote: (Originally Posted by jmurba) hem.... why a big nitrox bank ? I only usualy blend 200 litres of trimix . as for the air contamination as a matter of fact I think I will have to pay attention to this...it is maybye worth to install an o2 analyzer in the expansion bag on on the hose going from the bag to the intake of the stick...well I see thing clearer now tanks of all replies... regards jean mi I replied a bit too quickly (on company time). What I mean is that if you are topping up Rebreather tanks with only Helium, and/or a certain nitrox (that never changes as a result of topping up/remixing the nitrox only storage tank). You can always determine your He and N2 concentration by measuring only the O2. You would need a special reference table (the one above is valid for Heliair only). In order for this to work, you have to be very strict about always having the same Nitrox. If you are ok with hypoxic Heliair mixes (as I am), it is more practical. Providing your compressor is sucking clean air, it'll always be 20.9%. G __________________ Gilles http://www.dirrebreather.com Last edited by Gilles : 17th April 2007 at 23:46.
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18th April 2007, 07:06	#28 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 718	Re: anybody tried 1 atm blending ? Quote: (Originally Posted by Gilles) I replied a bit too quickly (on company time). What I mean is that if you are topping up Rebreather tanks with only Helium, and/or a certain nitrox (that never changes as a result of topping up/remixing the nitrox only storage tank). You can always determine your He and N2 concentration by measuring only the O2. You would need a special reference table (the one above is valid for Heliair only). In order for this to work, you have to be very strict about always having the same Nitrox. If you are ok with hypoxic Heliair mixes (as I am), it is more practical. Providing your compressor is sucking clean air, it'll always be 20.9%. G Well, it is not easy to blend trimix...as a matter of fact heliair would be a solution, after all we have ccr's and can intake as mutch o2 as we need in the circuit.... mabye would it be the better solution....an other solution would be to add a little bit of o2 and top with heliair.....many solutions, no perfect solution.... I must admit that I m a little bit lost... thanks anyway.. 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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18th April 2007, 14:25	#30 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 718	Re: anybody tried 1 atm blending ? Quote: (Originally Posted by Gilles) Jean Michel; Edited. Anytime you begin adding O2 to Heliair, it becomes Trimix, and then you'll start needing an He analyzer when you top up. Whenever you have 3 quantities (such as O2, N2, and He), as long as you know 2 of them, you can always determine the 3rd. So how do we keep track of the 2 quantities with a single measurement? By always using the same 2-component gas (air or constant nitrox, in this case EAN32). Attached is a table you can use to track your mix, providing you are only topping up with He, or EAN32. You can make any Trimix using any other EAN type (but a new table is needed for ech type). When topping up, as long as you are using only He and EAN32, you do not need an He analyzer and will always know your He fraction. Depending on what remains in the tank, you boost the additional amount of He you want (or none at all). By only measuring the O2, you determine the He by using the attached table (providing your EAN32 is EAN32). Go to the measured O2 level of left column, moving to the right, you get he fractions of He, EAN32, and N2 respectively. I wouldn't want to encourage Heliair use to anyone who isn't aware of the hazard of hypoxic dil. There is good advice in this forum about not using hypoxic when not needed. It is a risk I calculate as acceptable for myself. So, instead of spending 700-800 Euro on an analyzer, you only need to click a green blob for your Rebreather World colleague. Voila. Hi Gilles, thanks for spending the time to explain me all of that, after this disscussion I have now a mutch better view of the problem. I think that even if it is a little bit dear I will buy an he analyzer , to be more confortable but I agree with you on the point that it is possible to do without using the methodes we were discussing. however I decided to fine down the problem, I am going blend my weak trimix in a 30 liters twin tank using the old partial pressure method with the help of my booster if necessary, then I will fill my dil 2 liters, and after every dive I will top them up using the compressor or the booster to transfer....4000 liters of trimix on 2 2 liter tanks usualy on emptied by half will give me 10 dives...ten weeks more given that sometime meteo sends you to the pub ((-:. as you said I don't want an heliair, I am a shalow diver not willing to use hypoxic dils. I've semiclosely rebreathed my dil on electronic breakdowns and I was happy to get a descent fo2 in the mix not to **** my deco . 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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