Booster for rebreather - Oxygen and trimix

[Gone for diving]

On the other hand my friends booster (forget model) is great for doubles and bank bottles but pushes too much volume for use with small bottles making filling RB difficult and potentially dangerous.

Why can't you slow down the drive air?
A nice needle valve should work...

 

[Jack Hammer]

Why can't you slow down the drive air?
A nice needle valve should work...

You can and most people I know do just that. The issue with too big of a booster is the volume of gas they push per cycle can be too much for a small bottle and even cycling it slowly can generate a LOT of heat and quickly overfill a small bottle. That's not good when dealing with O2.

 

[tbone1004]

dual output whip, put an AL40/80 of the same mix that you want to fill onto the outlet and it will slow the fill rates down.

 

[happy-diver]

Only a problem if the Helium is contaminated. You can boost normal air from a clean diving compressor if you want to without problems. Just make sure it's clean.

Don't be lookin at me that's what he said


A needle valve on drive gas ha ha ha ha ha ha ha where do you read this stuff, use a ball valve
and remember to flush your lines when you are filling your storage bottles from rental bottles

 

[DiveGearExpress]

I'm wondering about using the same whips for pure oxygen and trimix, as it would make the oxygen clean setup no longer oxygen clean, right?

To answer your question... Yes, in many cases boosting trimix would contaminate an otherwise oxygen clean system.

Boosting pure O2 requires the entire system wetted components to be what is called 'oxygen clean', so your concerns regarding also using the same system to boost trimix are valid. There are no issues with boosting pure diving grade helium, it's going to be as clean as the oxygen. Helium is often boosted to produce trimix, and you can use the same oxygen booster on pure helium without concern. You can even use an oxygen booster to boost blended trimix, from a mechanical standpoint... but there are concerns regarding boosting trimix contaminated with hydrocarbons.

Boosting the already blended trimix is a different circumstance because trimix is usually made by adding helium and sometimes a little oxygen (or vice versa), and then topping off with ordinary compressed air. The concern, especially in a remote location, is the quality of the compressed air being used to make the trimix. If the air used to blend the trimix is not what is generally described as OCA purity, that is to say only the typical dive shop CGA Grade-E quality or of unknown quality (often the case in remote locations and private compressors without quarterly testing), then there is a substantial likely hood the trimix will contaminate the system with hydrocarbon condensate if a sufficient volume of trimix is boosted.

If you are able to determine the trimix was made with compressed air that is what the diving industry describes as OCA grade, then you are OK to proceed with boosting trimix. If not, then you risk contaminating the booster, whips and related components. While you are unlikely to experience a booster fire when boosting trimix, you may experience a booster fire when later boosting oxygen. Oxygen-related fires and explosions can result in serious injury or death. The 'clean state' of equipment applies only prior to initial use. Thereafter, periodic inspection and cleaning are a necessity for any booster.

How do the grades of compressed oxygen differ? | Dive Gear Express®

How do the grades of compressed oxygen differ? Nearly all compressed oxygen gas produced in the US is what is known as USP quality, meeting or exceeding United States Pharmacopeia quality ...

www.divegearexpress.com

Helium Grades for Breathing Gases in Diving | Dive Gear Express®

Helium Grades for Breathing Gases in Diving Pure helium is used in the blending of mixed breathing gases that contain an appropriate amount of oxygen suitable for diving applications. Helium ...

www.divegearexpress.com

Oxygen Cleanliness & Compatibility FAQ | Dive Gear Express®

www.divegearexpress.com

 

[monkkx]

To answer your question... Yes, in many cases boosting trimix would contaminate an otherwise oxygen clean system.

Boosting pure O2 requires the entire system wetted components to be what is called 'oxygen clean', so your concerns regarding also using the same system to boost trimix are valid. There are no issues with boosting pure diving grade helium, it's going to be as clean as the oxygen. Helium is often boosted to produce trimix, and you can use the same oxygen booster on pure helium without concern. You can even use an oxygen booster to boost blended trimix, from a mechanical standpoint... but there are concerns regarding boosting trimix contaminated with hydrocarbons.

Boosting the already blended trimix is a different circumstance because trimix is usually made by adding helium and sometimes a little oxygen (or vice versa), and then topping off with ordinary compressed air. The concern, especially in a remote location, is the quality of the compressed air being used to make the trimix. If the air used to blend the trimix is not what is generally described as OCA purity, that is to say only the typical dive shop CGA Grade-E quality or of unknown quality (often the case in remote locations and private compressors without quarterly testing), then there is a substantial likely hood the trimix will contaminate the system with hydrocarbon condensate if a sufficient volume of trimix is boosted.

If you are able to determine the trimix was made with compressed air that is what the diving industry describes as OCA grade, then you are OK to proceed with boosting trimix. If not, then you risk contaminating the booster, whips and related components. While you are unlikely to experience a booster fire when boosting trimix, you may experience a booster fire when later boosting oxygen. Oxygen-related fires and explosions can result in serious injury or death. The 'clean state' of equipment applies only prior to initial use. Thereafter, periodic inspection and cleaning are a necessity for any booster.

How do the grades of compressed oxygen differ? | Dive Gear Express®

How do the grades of compressed oxygen differ? Nearly all compressed oxygen gas produced in the US is what is known as USP quality, meeting or exceeding United States Pharmacopeia quality ...

www.divegearexpress.com

Helium Grades for Breathing Gases in Diving | Dive Gear Express®

Helium Grades for Breathing Gases in Diving Pure helium is used in the blending of mixed breathing gases that contain an appropriate amount of oxygen suitable for diving applications. Helium ...

www.divegearexpress.com

Oxygen Cleanliness & Compatibility FAQ | Dive Gear Express®

www.divegearexpress.com

thanks for the detailed explanation

 

[mdwalter]

I've got the same setup, GUE configured JJ. My mini while great on the 3L bottles takes a really really long time to top off the dual 7L bottles. The higher the boost pressure and bigger differential between supply and boosted pressure the longer it takes. So I only top them off as often as I'd like to.

Something like this is a nice compromise.

USUN Model:GB40-OL 160mm Driven single action air driven oxygen gas booster pump - Buy Air driven oxygen gas booster pump Product on WWW.U-SUN.CN

USUN Model: GB40-OL 160MM driven air driven oxygen gas booster pump find complete details about USUN Model:GB40-OL air driven oxygen gas booster pump on - WWW.U-SUN.CN

www.u-sun.cn

One of my friends picked one up and it is quick but not too quick for small bottles, good on stages, and slow but useable for doubles. The weight is about 35 pounds or so and still small enough, to be portable. It is comparable in size to a Haskel AG30.

I'd like to hear anyone's educated opinion on single action vs double action boosters. I've not been able to find direct information on whether a double action (boosts on both strokes) booster is either faster or more efficient than a single action. Clearly the single action will be smaller, lighter, and more portable than the double action of the same final ratio, but is there a down side to that which I should consider?
I'm currently comparing the uSun XB30-OL vs the XBD30-OL (about a $150 difference) or the GB40-OL vs the GBD40-OL (about a $200 more than the 30s, and again about $150 to go from single to double acting). Anyone have experience or advice on making the final selection among these models? I plan to use whichever I buy mainly to boost O2 into the AL13 for my RB, and occasionally to top off 80% full dilout tanks with trimix or HE followed by air (side mount LP45s, LP85s, or back mount double LP45s).

 

[mdwalter]

I'd like to hear anyone's educated opinion on single action vs double action boosters. I've not been able to find direct information on whether a double action (boosts on both strokes) booster is either faster or more efficient than a single action. Clearly the single action will be smaller, lighter, and more portable than the double action of the same final ratio, but is there a down side to that which I should consider?
I'm currently comparing the uSun XB30-OL vs the XBD30-OL (about a $150 difference) or the GB40-OL vs the GBD40-OL (about a $200 more than the 30s, and again about $150 to go from single to double acting). Anyone have experience or advice on making the final selection among these models? I plan to use whichever I buy mainly to boost O2 into the AL13 for my RB, and occasionally to top off 80% full dilout tanks with trimix or HE followed by air (side mount LP45s, LP85s, or back mount double LP45s).

Nevermind, I got impatient and went with the lowest cost option (XB30-OL). This left me with enough money to buy the better hose kit with QDs and all the CGA fittings for different input gasses.

 

[kissonerga.ccr]

I was actually looking at MPS band, feedbacks would be welcome

I’ve been using an MPS booster for a couple of years to boost 3L and 7L, both O2 and trimix, works as advertised, no complaints so far (well, one petty gripe: their analog gauges seem to be a little optimistic, by approximately 5 bars, on the drive gas side as well as the boosted side).

For an individual RB diver needs, a small size model would suffice, imho. I got the one pre-packaged in a travel case, comes complete with whips

 

[GF99/99]

I’ve been using an MPS booster for a couple of years to boost 3L and 7L, both O2 and trimix, works as advertised, no complaints so far (well, one petty gripe: their analog gauges seem to be a little optimistic, by approximately 5 bars, on the drive gas side as well as the boosted side).

For an individual RB diver needs, a small size model would suffice, imho. I got the one pre-packaged in a travel case, comes complete with whips

I am in the market for a booster also and the MPS units are #1 on my list right now.

May I ask what model you have? and aprox how much drive gas are you using for a 3L from 50b to 200b out of an O2 G that is say 50b?