Serial scrubber for the IDA 71

J. V. · 16th May 2007, 13:42

Quote:

The square filter is great, just make sure you manufacture a screen for over the powder. it is designed for a cartridge, so when that is not used you need to trap the 'sorb with a screen. It "can" do without it, but is lots better with it. Try it, and WOB will go down even more.

Thank you, I'll forward the info to my friend (he use my IDA now).

Quote:

The Joel Seymour rig was finally assembled by Joel in my shop while he stayed here in the house.

You're the Franken-son's father

Most of IDA 71 modified on The Rebreathersite says "based on D. Sutton idea".

undrh2o · 16th May 2007, 13:43

Quote: (Originally Posted by Dave Sutton)

The square filter is great, just make sure you manufacture a screen for over the powder. it is designed for a cartridge, so when that is not used you need to trap the 'sorb with a screen. It "can" do without it, but is lots better with it. Try it, and WOB will go down even more.

Paul, if you had back luck with the square one, try again with a screen. And you are correct with the measurements.

One more thing: The square one can be *half loaded* if you use a screen over the powder. One half can remain empty. Be careful!

The Joel Seymour rig was finally assembled by Joel in my shop while he stayed here in the house. He did a nice job.
Had someone looking over the shoulder.... on his first dives with it too... with Franken-Son. Good guy!

Dave

I like the OMS valve protectors as feet but it seems OMS doesn't sell them anymore.

bigblue · 16th May 2007, 15:48

Quote: (Originally Posted by paulraymaekers)

funny, I also had a square filter, I remember that the gaspath is only +/- 5X10 cm, and double length of the filter lenght, not?? the one with the plate in the middle inside???
I measured it in the lab... 4 times higher WOB than the oval ones (seems logic as length is twice and diameter is half..)
this one was not meant to be used with granular I think!

paul

I'm JV friends using the square filter and his old IDA, I'm using granular sorb (Spherasorb), I fully agree with you Paul but I wanted to test in order to make my conviction... It's done

to my expérience the square filter is better!

Quote: (Originally Posted by Dave Sutton)

The square filter is great, just make sure you manufacture a screen for over the powder. it is designed for a cartridge, so when that is not used you need to trap the 'sorb with a screen. It "can" do without it, but is lots better with it. Try it, and WOB will go down even more.

Dave

I've try both with and without "screen" as you sayed it's better with a screen and naturally and good diluent with high % He.

mverick · 17th May 2007, 01:55

Quote: (Originally Posted by J. V.)

Exactly like on other breather with same sorb capacity. Why more with the IDA? Cause of insulation? I don't think. I've use it deep in cold water and have never encounted CO2 hit du to filter conception. Friend used it and have not encounted. One have encounted, cause he have push the sorb too long. I've encounted cause of (very) bad sorb storage (completly dry...). Naturally, a 2kg sorb breather need to be used as a 2 kg sorb breather. Never start a planned deep and long dive with a half used filter. It's tru for all breathers. Even with my rEvo I always start a deep/long dive with fresh filters.
Sure, if all dive must be deep and long there is better breathers than IDA 71. But IMHO, for moderate dive, range 40/50 meters, in temperate or warm waters, IDA 71 is a very correct breather if used logically. Which means for me Ray DSV or equivalent, fresh sorb, helium based diluant.
That's not theory, that's practice.
Two filters in parallel give a better WOB (just a little in fact), but can not be quantified in matter of sorb efficiency. Gas pass where it's more easy to go, if a filter is packed less hard than the other, gas pass thru this filter and just this filter. There is no sure way to know before the dive where gas will go. After it's possible to have an idea if using colour changing sorb, but it's not accurate and dangerous cause need to push the filter to obtain great colour change -and results can be different during other dives.

3 people being OK and one person having a hit isn't a case study.

Everything isn't sorb capacity. If you can keep the material hot you gain efficiency. That's just how it is. How much heat you loose out of your scrubber is what will tell your efficiency of your scrubber. Radial or axial has some merit also, but mostly it's keeping the heat in the scrubber. It keeps the chemical reaction going.

Simple test. Couch dive your IDA. Grab your scrubber after 20min. Is it hot? If it is, you're loosing that heat to the water quick. Why? Because you can feel it's hot. It's transferring the heat to your hand. If it can do that, it can transfer it to the water. Grab a plastic bucket scrubber like a Prism or a Inspiration. It will still be warm. But since it's plastic it won't transfer the heat to your hand as fast.

I don't doubt what you did. I'm wondering why they built them like this myself. It isn't that they didn't have the resources to build it the other way. But then again, what was the IDA71 designed for? In a plane and what depth? I doubt 90 meters but maybe. I'm thinking around 45 meters. Anyone got true info from the manual on what depth it was designed for?

**Dave Sutton** · 17th May 2007, 02:06

Quote: (Originally Posted by mverick)

Simple test. Couch dive your IDA. Grab your scrubber after 20min. Is it hot?

Uhh.... why no, it's not....

We did bike riding with them (dry stationary bike) and they never got even warm to the toutch in air. Double wall scrubber.... designed to cool the inhaled gas by water contacting the exhale gas bolus, and to use that warm gas to insulate the scrubber bed. Pretty well done design. 2 birds with one stone.

The guys who are diving these as conversion platforms (some 200 at present) are enjoying pretty uniform results. With a 0% accident rate they must be doing something right. There's always room for improvement, but the scriubber ain't broke, so don't fix it.

Dave

mverick · 17th May 2007, 05:13

Quote: (Originally Posted by Dave Sutton)

Uhh.... why no, it's not....

We did bike riding with them (dry stationary bike) and they never got even warm to the toutch in air. Double wall scrubber.... designed to cool the inhaled gas by water contacting the exhale gas bolus, and to use that warm gas to insulate the scrubber bed. Pretty well done design. 2 birds with one stone.

The guys who are diving these as conversion platforms (some 200 at present) are enjoying pretty uniform results. With a 0% accident rate they must be doing something right. There's always room for improvement, but the scriubber ain't broke, so don't fix it.

Dave

Guess I should rephrase the hot. You're breath is 98degrees or so. Temp of the air going through the scrubber usually increases that temp. Other then the drop in temp from the DSV and the Counter lung and the hoses. So, air goes through the scubber and increases to >98 degrees.

I take it you're not telling me the temp of the outer part of your scrubber is <98 degrees. But, >98 degree outer temp with a water temp of <98 degrees means ya loose heat.

If I couch dive my IDA and grab the scrubber it's Hot, which is > then ambient in my home. Granted, I keep it at around 73 degree's give or take a few in my house.

Never did I say the scrubber was broke. In any of my posts. I wondered why it wasn't insulated. Not needed? Uh, it could help. But they chose not to for a reason.

To cool the inhale air? That would be a reason.
But in Cold water ie, Great lakes, I doubt that. Warm water diving I'd understand.

To extract moisture. That would be a reason.
But, why extract the moisture without an electronics package?

By the way, the double wall with a metal scrubber is what I had mentioned in a previous thread. But I had wanted an external of insulating quality. And a internal wall of metal. To hold heat and transfer it back to the medium.

divingtoors · 17th May 2007, 07:14

Hi

I found that with my IDA, after a dive, the scrubber will be quite warm to the touch. Maybe because our water is 17'C..

However, I found that most of the scrubber material is wet inside, and not much water accumulated in the inhalation side in the "double wall" after a 90 minute dive. (with one scrubber only). In the "deeper", parts of the dive, (read 15m / 50ft) there is also noticeable shortness of breath and the feeling of oxygen starvation, which I presume is the onset of hypercapnia. Accent to shallower depths alleviates this problem.

The scrubber is placed correctly, with the seam down.

Will the wetness of the scrubber ebd not increase WOB or decrease the CO2 scrubbing functionality?

If so, I would have reckoned that the scrubber might have to be placed with the seam up, so that the warm moist exhalation gas can go through the outer wall first, thereby condensing against the cold outer wall, and thus letting drier air though the scrubber bed and thus keeping the bed more efficient.
The scrubber material should have enough of its own moisture to "re-moisten: the inhalation gas.

Currently the moist exhalation gas is passing through the scrubber bed first, and the scrubber absorbing the moisture,therefore not leaving much to condense on the scrubber outer wall, which sounds counterpoductive..

any help on this

Johan

Marc T · 17th May 2007, 08:41

Quote: (Originally Posted by bigblue)

I've try both with and without "screen" as you sayed it's better with a screen and naturally and good diluent with high % He.

I also own a square scrubber but never tried it yet.
Could you ( or somehone else ) please send a pic of this screen, I dont really understand the need and how it can made the WOB better.
Do it allows you to let a space without sorb at the bottom of the scrubber? Is it the way to use it?

Thanks

Marc

**Dave Sutton** · 17th May 2007, 13:22

Quote: (Originally Posted by Marc T)

I also own a square scrubber but never tried it yet.
Could you ( or somehone else ) please send a pic of this screen, I dont really understand the need and how it can made the WOB better.
Do it allows you to let a space without sorb at the bottom of the scrubber? Is it the way to use it?

Thanks

Marc

Just make a square of heavy screen (really "perforated metal", you want it to be fairly strong). This makes a "sorb free" space at the end, where the gas "turns around". The springs in the lid should hold the screen down, helps prevent the 'sorb from loosening up when vibrated. What you are doing, in essence, is making up a cheap iteration of the rEvo scrubber... two in series. This square scrubber was never intended to take powder, but a brick-like cartridge. The short answer is "yes", it makes a small smace where the is no 'sorb at the bottom.

I'm not sure what the point of the other debate is, "why" and "how" etc... The scrubbers work fine, use them.
If you want a plastic one, make it. Make a rapid load radial. Nothing is so good that it cannot be improved.

Dave

bythesea · 17th May 2007, 14:13

Quote: (Originally Posted by Dave Sutton)

Just make a square of heavy screen (really "perforated metal", you want it to be fairly strong). This makes a "sorb free" space at the end, where the gas "turns around".

Hey Dave,
Do you happen to have any more of these square scrubbers lurking in odd corners???

16th May 2007, 13:42	#21 (permalink)
J. V. RBW Member Current Rebreather/s: rEvo Other Rebreather/s: Not Bought Yet rEvo Join Date: Mar 2006 Location: Lot & Savoie Posts: 249	Re: Serial scrubber for the IDA 71 Quote: The square filter is great, just make sure you manufacture a screen for over the powder. it is designed for a cartridge, so when that is not used you need to trap the 'sorb with a screen. It "can" do without it, but is lots better with it. Try it, and WOB will go down even more. Thank you, I'll forward the info to my friend (he use my IDA now). Quote: The Joel Seymour rig was finally assembled by Joel in my shop while he stayed here in the house. You're the Franken-son's father Most of IDA 71 modified on The Rebreathersite says "based on D. Sutton idea". __________________ -------------------- Jacques NPSFQQA-EDS IT # 007 (remué non agité)
(Offline)

16th May 2007, 13:43	#22 (permalink)
undrh2o Chris Miller Current Rebreather/s: Other CCR Dolphin Home Build Other Rebreather/s: Inspiration Classic Other CCR Dolphin Home Build Join Date: Apr 2006 Location: Ottawa, Canada Posts: 206	Re: Serial scrubber for the IDA 71 Quote: (Originally Posted by Dave Sutton) The square filter is great, just make sure you manufacture a screen for over the powder. it is designed for a cartridge, so when that is not used you need to trap the 'sorb with a screen. It "can" do without it, but is lots better with it. Try it, and WOB will go down even more. Paul, if you had back luck with the square one, try again with a screen. And you are correct with the measurements. One more thing: The square one can be half loaded if you use a screen over the powder. One half can remain empty. Be careful! The Joel Seymour rig was finally assembled by Joel in my shop while he stayed here in the house. He did a nice job. Had someone looking over the shoulder.... on his first dives with it too... with Franken-Son. Good guy! Dave I like the OMS valve protectors as feet but it seems OMS doesn't sell them anymore.
(Offline)

16th May 2007, 15:48	#23 (permalink)
bigblue New Member Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: Dec 2005 Location: FRANCE Posts: 14	Re: Serial scrubber for the IDA 71 Quote: (Originally Posted by paulraymaekers) funny, I also had a square filter, I remember that the gaspath is only +/- 5X10 cm, and double length of the filter lenght, not?? the one with the plate in the middle inside??? I measured it in the lab... 4 times higher WOB than the oval ones (seems logic as length is twice and diameter is half..) this one was not meant to be used with granular I think! paul I'm JV friends using the square filter and his old IDA, I'm using granular sorb (Spherasorb), I fully agree with you Paul but I wanted to test in order to make my conviction... It's done to my expérience the square filter is better! Quote: (Originally Posted by Dave Sutton) The square filter is great, just make sure you manufacture a screen for over the powder. it is designed for a cartridge, so when that is not used you need to trap the 'sorb with a screen. It "can" do without it, but is lots better with it. Try it, and WOB will go down even more. Dave I've try both with and without "screen" as you sayed it's better with a screen and naturally and good diluent with high % He.
(Offline)

17th May 2007, 01:55	#24 (permalink)
mverick ScubaPimp Current Rebreather/s: Megalodon Other CCR Home Build Other Rebreather/s: Other CCR Home Build Join Date: Aug 2005 Posts: 555	Re: Serial scrubber for the IDA 71 Quote: (Originally Posted by J. V.) Exactly like on other breather with same sorb capacity. Why more with the IDA? Cause of insulation? I don't think. I've use it deep in cold water and have never encounted CO2 hit du to filter conception. Friend used it and have not encounted. One have encounted, cause he have push the sorb too long. I've encounted cause of (very) bad sorb storage (completly dry...). Naturally, a 2kg sorb breather need to be used as a 2 kg sorb breather. Never start a planned deep and long dive with a half used filter. It's tru for all breathers. Even with my rEvo I always start a deep/long dive with fresh filters. Sure, if all dive must be deep and long there is better breathers than IDA 71. But IMHO, for moderate dive, range 40/50 meters, in temperate or warm waters, IDA 71 is a very correct breather if used logically. Which means for me Ray DSV or equivalent, fresh sorb, helium based diluant. That's not theory, that's practice. Two filters in parallel give a better WOB (just a little in fact), but can not be quantified in matter of sorb efficiency. Gas pass where it's more easy to go, if a filter is packed less hard than the other, gas pass thru this filter and just this filter. There is no sure way to know before the dive where gas will go. After it's possible to have an idea if using colour changing sorb, but it's not accurate and dangerous cause need to push the filter to obtain great colour change -and results can be different during other dives. 3 people being OK and one person having a hit isn't a case study. Everything isn't sorb capacity. If you can keep the material hot you gain efficiency. That's just how it is. How much heat you loose out of your scrubber is what will tell your efficiency of your scrubber. Radial or axial has some merit also, but mostly it's keeping the heat in the scrubber. It keeps the chemical reaction going. Simple test. Couch dive your IDA. Grab your scrubber after 20min. Is it hot? If it is, you're loosing that heat to the water quick. Why? Because you can feel it's hot. It's transferring the heat to your hand. If it can do that, it can transfer it to the water. Grab a plastic bucket scrubber like a Prism or a Inspiration. It will still be warm. But since it's plastic it won't transfer the heat to your hand as fast. I don't doubt what you did. I'm wondering why they built them like this myself. It isn't that they didn't have the resources to build it the other way. But then again, what was the IDA71 designed for? In a plane and what depth? I doubt 90 meters but maybe. I'm thinking around 45 meters. Anyone got true info from the manual on what depth it was designed for?
(Online)

17th May 2007, 02:06	#25 (permalink)
Dave Sutton Diveshop of Horrors Current Rebreather/s: Sport Kiss MK 15.X rEvo Other CCR Azimuth Home Build Other Rebreather/s: Evolution Megalodon rEvo Other CCR Azimuth Home Build Join Date: Jun 2006 Location: Narragansett, Rhode Island and Hackettstown, New Jersey Posts: 2,907	Re: Serial scrubber for the IDA 71 Quote: (Originally Posted by mverick) Simple test. Couch dive your IDA. Grab your scrubber after 20min. Is it hot? Uhh.... why no, it's not.... We did bike riding with them (dry stationary bike) and they never got even warm to the toutch in air. Double wall scrubber.... designed to cool the inhaled gas by water contacting the exhale gas bolus, and to use that warm gas to insulate the scrubber bed. Pretty well done design. 2 birds with one stone. The guys who are diving these as conversion platforms (some 200 at present) are enjoying pretty uniform results. With a 0% accident rate they must be doing something right. There's always room for improvement, but the scriubber ain't broke, so don't fix it. Dave __________________ "Silent Diving with No Bubbles and No Politics".... www.nobubblediving.com Last edited by Dave Sutton : 17th May 2007 at 02:09.
(Offline)

17th May 2007, 05:13	#26 (permalink)
mverick ScubaPimp Current Rebreather/s: Megalodon Other CCR Home Build Other Rebreather/s: Other CCR Home Build Join Date: Aug 2005 Posts: 555	Re: Serial scrubber for the IDA 71 Quote: (Originally Posted by Dave Sutton) Uhh.... why no, it's not.... We did bike riding with them (dry stationary bike) and they never got even warm to the toutch in air. Double wall scrubber.... designed to cool the inhaled gas by water contacting the exhale gas bolus, and to use that warm gas to insulate the scrubber bed. Pretty well done design. 2 birds with one stone. The guys who are diving these as conversion platforms (some 200 at present) are enjoying pretty uniform results. With a 0% accident rate they must be doing something right. There's always room for improvement, but the scriubber ain't broke, so don't fix it. Dave Guess I should rephrase the hot. You're breath is 98degrees or so. Temp of the air going through the scrubber usually increases that temp. Other then the drop in temp from the DSV and the Counter lung and the hoses. So, air goes through the scubber and increases to >98 degrees. I take it you're not telling me the temp of the outer part of your scrubber is <98 degrees. But, >98 degree outer temp with a water temp of <98 degrees means ya loose heat. If I couch dive my IDA and grab the scrubber it's Hot, which is > then ambient in my home. Granted, I keep it at around 73 degree's give or take a few in my house. Never did I say the scrubber was broke. In any of my posts. I wondered why it wasn't insulated. Not needed? Uh, it could help. But they chose not to for a reason. To cool the inhale air? That would be a reason. But in Cold water ie, Great lakes, I doubt that. Warm water diving I'd understand. To extract moisture. That would be a reason. But, why extract the moisture without an electronics package? By the way, the double wall with a metal scrubber is what I had mentioned in a previous thread. But I had wanted an external of insulating quality. And a internal wall of metal. To hold heat and transfer it back to the medium.
(Online)

17th May 2007, 07:14	#27 (permalink)
divingtoors RBW Member Current Rebreather/s: Home Build Other Rebreather/s: Not Bought Yet Home Build Join Date: Mar 2006 Location: Cape Town Posts: 103	Re: Serial scrubber for the IDA 71 Hi I found that with my IDA, after a dive, the scrubber will be quite warm to the touch. Maybe because our water is 17'C.. However, I found that most of the scrubber material is wet inside, and not much water accumulated in the inhalation side in the "double wall" after a 90 minute dive. (with one scrubber only). In the "deeper", parts of the dive, (read 15m / 50ft) there is also noticeable shortness of breath and the feeling of oxygen starvation, which I presume is the onset of hypercapnia. Accent to shallower depths alleviates this problem. The scrubber is placed correctly, with the seam down. Will the wetness of the scrubber ebd not increase WOB or decrease the CO2 scrubbing functionality? If so, I would have reckoned that the scrubber might have to be placed with the seam up, so that the warm moist exhalation gas can go through the outer wall first, thereby condensing against the cold outer wall, and thus letting drier air though the scrubber bed and thus keeping the bed more efficient. The scrubber material should have enough of its own moisture to "re-moisten: the inhalation gas. Currently the moist exhalation gas is passing through the scrubber bed first, and the scrubber absorbing the moisture,therefore not leaving much to condense on the scrubber outer wall, which sounds counterpoductive.. any help on this Johan
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17th May 2007, 08:41	#28 (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: 498	Re: Serial scrubber for the IDA 71 Quote: (Originally Posted by bigblue) I've try both with and without "screen" as you sayed it's better with a screen and naturally and good diluent with high % He. I also own a square scrubber but never tried it yet. Could you ( or somehone else ) please send a pic of this screen, I dont really understand the need and how it can made the WOB better. Do it allows you to let a space without sorb at the bottom of the scrubber? Is it the way to use it? Thanks Marc
(Offline)

17th May 2007, 13:22	#29 (permalink)
Dave Sutton Diveshop of Horrors Current Rebreather/s: Sport Kiss MK 15.X rEvo Other CCR Azimuth Home Build Other Rebreather/s: Evolution Megalodon rEvo Other CCR Azimuth Home Build Join Date: Jun 2006 Location: Narragansett, Rhode Island and Hackettstown, New Jersey Posts: 2,907	Re: Serial scrubber for the IDA 71 Quote: (Originally Posted by Marc T) I also own a square scrubber but never tried it yet. Could you ( or somehone else ) please send a pic of this screen, I dont really understand the need and how it can made the WOB better. Do it allows you to let a space without sorb at the bottom of the scrubber? Is it the way to use it? Thanks Marc Just make a square of heavy screen (really "perforated metal", you want it to be fairly strong). This makes a "sorb free" space at the end, where the gas "turns around". The springs in the lid should hold the screen down, helps prevent the 'sorb from loosening up when vibrated. What you are doing, in essence, is making up a cheap iteration of the rEvo scrubber... two in series. This square scrubber was never intended to take powder, but a brick-like cartridge. The short answer is "yes", it makes a small smace where the is no 'sorb at the bottom. I'm not sure what the point of the other debate is, "why" and "how" etc... The scrubbers work fine, use them. If you want a plastic one, make it. Make a rapid load radial. Nothing is so good that it cannot be improved. Dave __________________ "Silent Diving with No Bubbles and No Politics".... www.nobubblediving.com Last edited by Dave Sutton : 17th May 2007 at 13:24.
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17th May 2007, 14:13	#30 (permalink)
bythesea RBW Member Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Nov 2006 Location: W.Mass, USA Posts: 75	Re: Serial scrubber for the IDA 71 Quote: (Originally Posted by Dave Sutton) Just make a square of heavy screen (really "perforated metal", you want it to be fairly strong). This makes a "sorb free" space at the end, where the gas "turns around". Hey Dave, Do you happen to have any more of these square scrubbers lurking in odd corners???
(Online)

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