inspiration half fill adaptor

Ant Slegg · 16th November 2007, 11:21

Quote: (Originally Posted by Mdemon)

WOB would increase too...

Yep - I calculate that the wall thickness would need to be just under 30% of the Inside Diameter radius.

***jradomski*** · 16th November 2007, 12:09

Quote: (Originally Posted by toe)

Has anyone made or thought of making a half fill scrubber adaptor for the ybod? (vision)

Cheers
Tony

There is a post on the Inspiration list archives that was from Martin.. I don't remember the specifics but if I remember correctly with a "half fill adapter" the testing that was done at the factory showed there was a much shorter time than expected.. My guess is that AP did alot of testing before deciding on how much scrubber (length) was needed for the evolution..

dave t · 16th November 2007, 15:05

Quote: (Originally Posted by jradomski)

There is a post on the Inspiration list archives that was from Martin.. I donlt remember the specifics but if I remember correctly with a "half fill adapter" the testing that was done at the factory showed there was a much shorter time than expected.. My guess is that AP did alot of testing before deciding on how much scrubber (length) was needed for the eveloution..

Yes I tested it, in fact I still have it in my shed somewhere. it was pretty useless, duration was much less than half the full scrubber with much more chance of breakthrough. Please do not try to modify your existing scrubber to get a half fill. I guarantee it will end in tears!!

Dave

Jack · 18th November 2007, 01:32

Quote: (Originally Posted by dave t)

Yes I tested it, in fact I still have it in my shed somewhere. it was pretty useless, duration was much less than half the full scrubber with much more chance of breakthrough. Please do not try to modify your existing scrubber to get a half fill. I guarantee it will end in tears!!

Dave

That about sums it up.

Molecular Products Ltd · 26th November 2007, 14:31

Hi,

couple of real easy points on this and most have been covered.

You may reduce the size to a point where the residence time is not sufficient and get bypass - this is bad

The biggest part of the scrubber would be mass transfer zone (the bit where the reaction happens that you can never use, see attachment) and very little 'capacity left' to use, - this is bad (not cost effective

if the mass transfer zone was the same size as the scrubber unit it would not work at all - this is bad.

I hope the attachted document explains how an absorber works

Regards

Stephen

paulraymaekers · 26th November 2007, 15:27

Quote: (Originally Posted by Molecular Products Ltd)

Hi,
couple of real easy points on this and most have been covered.
You may reduce the size to a point where the residence time is not sufficient and get bypass - this is bad
The biggest part of the scrubber would be mass transfer zone (the bit where the reaction happens that you can never use, see attachment) and very little 'capacity left' to use, - this is bad (not cost effective
if the mass transfer zone was the same size as the scrubber unit it would not work at all - this is bad.
I hope the attachted document explains how an absorber works
Regards

Stephen

Hello Stephen, I would just add that the reaction zone becomes bigger with increasing depth and decreasing temperature. So together with extersion level and gas speed you have the main factors that determine scrubber duration

regards and thanks for the clear explanation

paul

Shaunzxr · 26th November 2007, 22:44

Just do what I do
Fill scrubber, 1 hour dive, take scrubber out of unit, bag and seal til the next dive.
Iv'e left it for a month with no problems.
Just make a note on the srubber how long its been used for,
I forgot to do this and had to bin it.

Tino de Rijk · 27th November 2007, 05:25

Quote: (Originally Posted by dave t)

Yes I tested it, in fact I still have it in my shed somewhere. it was pretty useless, duration was much less than half the full scrubber with much more chance of breakthrough. Please do not try to modify your existing scrubber to get a half fill. I guarantee it will end in tears!!

Dave

some long, long time ago (I'm getting old....) APD made a half-way-insert for the Classic. It was an elegant & simple construction, basically 2 spider plates internally connected with three rods, so no issue with higher WOB or pressure transducing to keep the sorb compressed. I dived it many times, BUT very only for short & shallow dives. I still have it somewhere around, like Dave...
Very soon after the very first Inspo's, APD decided it was too much abused by "penny-wise, pound-foolish" divers and binned it.

A bit later on, subsequent testing by APD (who at that time invested massively in a huge full-size Rebreather test facility - look at the photos on their website!) verified indeed that it lasted far less than half the time of a full load, i.e. not 3 / 2 = 1.5 hour but far less (something like only 45 minutes or so, and then only relatively shallow).

So in fact a relatively costly rather than money-safing measure......

I do now what another guy suggested: after a day's diving I dry out the breather, put the partly spent scrubber back in and seal it all airtight (=empty C/L's like you do in a negative pressure test, close mouthpiece etc.). Alternatively you could seal it outboard in an airtight container.

As to storage time: consider the following: If you buy a new tub of Sofnolime, it is guaranteed for 5 years to work (if unused of course) according to the label on the tub. Basically as long as not subjected to new CO2 it will not deteriorate further. So if between dives you makes sure it is in a CO2-less environment, you're good. And of course this includes an environment that initially contains a bit of CO2, like a closed plastic bag or the closed-off rebreather itself, as it will quickly consume the very little bit of CO2 left in the packaging quickly and then "sit still", i.e. go inert.

Bottom line: forget it: not a real money-safer; just store between dives in a sealed environment to reduce further degradation due to CO2 consumption/burning.

BTW: I also very seriously doubt if the TempStik would be worth a thing anymore with a half-way insert, of may even give wrong info and/or errors.

Ciao,

Tino.

Tino de Rijk · 27th November 2007, 05:30

Quote: (Originally Posted by Molecular Products Ltd)

Hi,

couple of real easy points on this and most have been covered.

You may reduce the size to a point where the residence time is not sufficient and get bypass - this is bad

The biggest part of the scrubber would be mass transfer zone (the bit where the reaction happens that you can never use, see attachment) and very little 'capacity left' to use, - this is bad (not cost effective

if the mass transfer zone was the same size as the scrubber unit it would not work at all - this is bad.

I hope the attachted document explains how an absorber works

Regards

Stephen

Thanks very much for a nice, clear, short article on scrubber workings. Moderator(s): suggest it gets a place in the library!

ciao,

Tino.

***Beanie*** · 27th November 2007, 07:35

Quote: (Originally Posted by Tino de Rijk)

Thanks very much for a nice, clear, short article on scrubber workings. Moderator(s): suggest it gets a place in the library!

ciao,

Tino.

Yes, need to get permission first though...

16th November 2007, 11:21	#11 (permalink)
Ant Slegg Still Learning.... Current Rebreather/s: Ouroboros Other Rebreather/s: Ouroboros Join Date: Nov 2005 Location: Grevenmacher, Luxembourg Posts: 167	Re: inspiration half fill adaptor Quote: (Originally Posted by Mdemon) WOB would increase too... Yep - I calculate that the wall thickness would need to be just under 30% of the Inside Diameter radius. __________________ Ant' S Learning to dive since 1990...
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16th November 2007, 12:09	#12 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Home Build Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Home Build Join Date: Mar 2005 Location: "Da" Bronx Posts: 2,871	Re: inspiration half fill adaptor Quote: (Originally Posted by toe) Has anyone made or thought of making a half fill scrubber adaptor for the ybod? (vision) Cheers Tony There is a post on the Inspiration list archives that was from Martin.. I don't remember the specifics but if I remember correctly with a "half fill adapter" the testing that was done at the factory showed there was a much shorter time than expected.. My guess is that AP did alot of testing before deciding on how much scrubber (length) was needed for the evolution.. __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated. Last edited by jradomski : 16th November 2007 at 20:36. Reason: typos
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16th November 2007, 15:05	#13 (permalink)
dave t Custom Title Allowed! Current Rebreather/s: Inspiration Classic Inspiration Vision Evolution Sport Kiss Classic Kiss Dolphin Ray Azimuth Home Build Other Rebreather/s: Dolphin Ray Azimuth Home Build Join Date: May 2005 Location: UK Posts: 654	Re: inspiration half fill adaptor Quote: (Originally Posted by jradomski) There is a post on the Inspiration list archives that was from Martin.. I donlt remember the specifics but if I remember correctly with a "half fill adapter" the testing that was done at the factory showed there was a much shorter time than expected.. My guess is that AP did alot of testing before deciding on how much scrubber (length) was needed for the eveloution.. Yes I tested it, in fact I still have it in my shed somewhere. it was pretty useless, duration was much less than half the full scrubber with much more chance of breakthrough. Please do not try to modify your existing scrubber to get a half fill. I guarantee it will end in tears!! Dave
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18th November 2007, 01:32	#14 (permalink)
Jack Easy Does It Current Rebreather/s: Other SCR Other Rebreather/s: Other SCR Join Date: Apr 2005 Location: ireland Posts: 7	Re: inspiration half fill adaptor Quote: (Originally Posted by dave t) Yes I tested it, in fact I still have it in my shed somewhere. it was pretty useless, duration was much less than half the full scrubber with much more chance of breakthrough. Please do not try to modify your existing scrubber to get a half fill. I guarantee it will end in tears!! Dave That about sums it up. __________________ JACK www.dublinbaydiving.com
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26th November 2007, 15:27	#16 (permalink)
paulraymaekers rEvo's daddy Current Rebreather/s: rEvo Other CCR Home Build Other Rebreather/s: rEvo Other CCR Home Build Join Date: May 2005 Location: belgium Posts: 1,432	Re: inspiration half fill adaptor Quote: (Originally Posted by Molecular Products Ltd) Hi, couple of real easy points on this and most have been covered. You may reduce the size to a point where the residence time is not sufficient and get bypass - this is bad The biggest part of the scrubber would be mass transfer zone (the bit where the reaction happens that you can never use, see attachment) and very little 'capacity left' to use, - this is bad (not cost effective if the mass transfer zone was the same size as the scrubber unit it would not work at all - this is bad. I hope the attachted document explains how an absorber works Regards Stephen Hello Stephen, I would just add that the reaction zone becomes bigger with increasing depth and decreasing temperature. So together with extersion level and gas speed you have the main factors that determine scrubber duration regards and thanks for the clear explanation paul __________________ www.rEvo-rebreathers.com .... the earth is flat, Elvis is alive, and radial scrubbers give longer dwell time than axials...
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26th November 2007, 22:44	#17 (permalink)
Shaunzxr Inspo Luver Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Apr 2005 Location: UK, midlands Posts: 87	Re: inspiration half fill adaptor Just do what I do Fill scrubber, 1 hour dive, take scrubber out of unit, bag and seal til the next dive. Iv'e left it for a month with no problems. Just make a note on the srubber how long its been used for, I forgot to do this and had to bin it.
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27th November 2007, 05:25	#18 (permalink)
Tino de Rijk Old, maybe one day wise Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Evolution Join Date: Mar 2006 Location: Amsterdam Posts: 319	Re: inspiration half fill adaptor Quote: (Originally Posted by dave t) Yes I tested it, in fact I still have it in my shed somewhere. it was pretty useless, duration was much less than half the full scrubber with much more chance of breakthrough. Please do not try to modify your existing scrubber to get a half fill. I guarantee it will end in tears!! Dave some long, long time ago (I'm getting old....) APD made a half-way-insert for the Classic. It was an elegant & simple construction, basically 2 spider plates internally connected with three rods, so no issue with higher WOB or pressure transducing to keep the sorb compressed. I dived it many times, BUT very only for short & shallow dives. I still have it somewhere around, like Dave... Very soon after the very first Inspo's, APD decided it was too much abused by "penny-wise, pound-foolish" divers and binned it. A bit later on, subsequent testing by APD (who at that time invested massively in a huge full-size Rebreather test facility - look at the photos on their website!) verified indeed that it lasted far less than half the time of a full load, i.e. not 3 / 2 = 1.5 hour but far less (something like only 45 minutes or so, and then only relatively shallow). So in fact a relatively costly rather than money-safing measure...... I do now what another guy suggested: after a day's diving I dry out the breather, put the partly spent scrubber back in and seal it all airtight (=empty C/L's like you do in a negative pressure test, close mouthpiece etc.). Alternatively you could seal it outboard in an airtight container. As to storage time: consider the following: If you buy a new tub of Sofnolime, it is guaranteed for 5 years to work (if unused of course) according to the label on the tub. Basically as long as not subjected to new CO2 it will not deteriorate further. So if between dives you makes sure it is in a CO2-less environment, you're good. And of course this includes an environment that initially contains a bit of CO2, like a closed plastic bag or the closed-off rebreather itself, as it will quickly consume the very little bit of CO2 left in the packaging quickly and then "sit still", i.e. go inert. Bottom line: forget it: not a real money-safer; just store between dives in a sealed environment to reduce further degradation due to CO2 consumption/burning. BTW: I also very seriously doubt if the TempStik would be worth a thing anymore with a half-way insert, of may even give wrong info and/or errors. Ciao, Tino.
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27th November 2007, 05:30	#19 (permalink)
Tino de Rijk Old, maybe one day wise Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Evolution Join Date: Mar 2006 Location: Amsterdam Posts: 319	Re: inspiration half fill adaptor Quote: (Originally Posted by Molecular Products Ltd) Hi, couple of real easy points on this and most have been covered. You may reduce the size to a point where the residence time is not sufficient and get bypass - this is bad The biggest part of the scrubber would be mass transfer zone (the bit where the reaction happens that you can never use, see attachment) and very little 'capacity left' to use, - this is bad (not cost effective if the mass transfer zone was the same size as the scrubber unit it would not work at all - this is bad. I hope the attachted document explains how an absorber works Regards Stephen Thanks very much for a nice, clear, short article on scrubber workings. Moderator(s): suggest it gets a place in the library! ciao, Tino.
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27th November 2007, 07:35	#20 (permalink)
*Beanie* Politeness officer Current Rebreather/s: Inspiration Classic Other Rebreather/s: Inspiration Vision Join Date: Jan 2005 Location: In da house! yeah baby! Posts: 3,205	Re: inspiration half fill adaptor Quote: (Originally Posted by Tino de Rijk) Thanks very much for a nice, clear, short article on scrubber workings. Moderator(s): suggest it gets a place in the library! ciao, Tino. Yes, need to get permission first though... __________________ Beanie Gallery Admin & Library Assistant. www.outlawdivers.org.uk www.beandiving.co.uk www.beanengineering.co.uk www.divelife.co.uk
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