Channeling - Defined...?

netmage · 6th December 2007, 16:13

Been following the discussions on CO2, scrubber packing etc.. and I'm a little confused... What exactly is channeling...?

Is it physical 'gaps' in the scrubber bed; whereby gas can find the path of least resistance w/o being scrubbed through loose material...?

Or is it chemical 'gaps' in the scrubber bed; as in the repacking case, whereby gas finds a path thru used material in the scrubber bed...?

-Tim
(I pick up my meg tomorrow, class starts 1/24....)

Mark Chase · 6th December 2007, 16:22

Quote: (Originally Posted by netmage)

Been following the discussions on CO2, scrubber packing etc.. and I'm a little confused... What exactly is channeling...?

Is it physical 'gaps' in the scrubber bed; whereby gas can find the path of least resistance w/o being scrubbed through loose material...?

Or is it chemical 'gaps' in the scrubber bed; as in the repacking case, whereby gas finds a path thru used material in the scrubber bed...?

-Tim
(I pick up my meg tomorrow, class starts 1/24....)

Spot on

Settlement of the scrubber in a horizontal position may leave a loose fill or even a physical hole up the side of a scrubber (something the design of the rEvo scrubber seems more prone to IMHO)

Mainly its clumping of the sorb or something like the repacking incident which leaves a path through the scrubber of spent lime.

Whilst the path may be small C02 has a cumulative effect so will gradually build up during the dive.

ATB

Mark

paulraymaekers · 6th December 2007, 16:39

Quote: (Originally Posted by Mark Chase)

Settlement of the scrubber in a horizontal position may leave a loose fill or even a physical hole up the side of a scrubber (something the design of the rEvo scrubber seems more prone to IMHO)

uh??

hi Marc, where do you get that??

I think it is just the unit with the least possible chance for channeling: the only thing that can happen is that with heavy bumping the sorb would get more compacted towards the bottom of the scrubber!

remember in horizontal position the gasflow trough the scrubber is vertical!

regards
paul

***jradomski*** · 6th December 2007, 17:26

Quote: (Originally Posted by Mark Chase)

Spot on

Settlement of the scrubber in a horizontal position may leave a loose fill or even a physical hole up the side of a scrubber (something the design of the rEvo scrubber seems more prone to IMHO)

Mainly its clumping of the sorb or something like the repacking incident which leaves a path through the scrubber of spent lime.

Whilst the path may be small C02 has a cumulative effect so will gradually build up during the dive.

ATB

Mark

Mark,
sorry to say this but you are talking through your arse..

The each rEVo scruber is relatively short so packing is quite easy.. if you follow the proper packing procedure it packs very quickly and consistently.. if there is any settling (very doubtful if you follow the packing procedure) the spring could easily take up any space that has formed..

the short length probably makes it one of the most consitent scrubbers to pack and having 2 scrubbers make it highly unlikely that there will be a single path in BOTH scrubers to let gas bypass....

decoweenie · 6th December 2007, 18:25

Quote: (Originally Posted by jradomski)

Mark,
sorry to say this but you are talking through your arse..

Oh come on, Joe!

Are you telling me that Mark Chase is talking thru his arse...

... again ?

**sfldiver** · 6th December 2007, 18:38

Gotta love those EAC's my Optima uses!

And Tim, congrats on teh Meg purchase!

I'm looking forward to seeing you out there with us on a Florida S.C.R.U.B. dive blowing no bubbles!

Adrian

AD_ward9 · 6th December 2007, 18:48

Joe and Mark: you are both right.

Mark's definition is the correct one of channelling. Many axial scrubbers suffer badly from channelling when the scrubber is horizontal.

Joe rightly points out that the rEvo is not as prone to channelling as most axial scrubbers are, because it is oriented vertically when the diver is prone, and also has opportunity for the gas to mix between the two scrubbers, so raw unscrubbed gas does not go through a channel on the second scrubber even if both were to channel.

However, I would like to see the figures for when the diver is vertical, such as in a deco reading his fishing journal or whatever he gets put onto the trapeze for amusement.

Alex

***jradomski*** · 6th December 2007, 19:08

Quote: (Originally Posted by AD_ward9)

Joe and Mark: you are both right.

Mark's definition is the correct one of channelling. Many axial scrubbers suffer badly from channelling when the scrubber is horizontal.

Joe rightly points out that the rEvo is not as prone to channelling as most axial scrubbers are, because it is oriented vertically when the diver is prone, and also has opportunity for the gas to mix between the two scrubbers, so raw unscrubbed gas does not go through a channel on the second scrubber even if both were to channel.

However, I would like to see the figures for when the diver is vertical, such as in a deco reading his fishing journal or whatever he gets put onto the trapeze for amusement.

Alex

Alex,

I really don't see the rEvo channeling.. When you following the packing procedure, the amount of sorb you is is very consistent.. so once you get the technque down there is very little variation from scrubber to scrubber.. so I see you either pack it really badly (probably by not having someone show you the technique) and you have a loose fill on many dives or you get a good fill.. Following the techniques that are taught in the class, I havent seen a poorly packed scrubber yet..

Mark Chase · 6th December 2007, 19:25

I dont see any scrubber channeling if its packed properly, surely thats the point.

The settlement isnt going to take place during the dive its going to occur in the car on the way there and on the boat on the journy out

A vertical scrubber is surely less likley to suffer this than a horizontal one?

It seems logical to me.

But hey i could be talking out of my arse.

ATB

Mark

ReikiMaster · 6th December 2007, 22:21

Quote: (Originally Posted by Mark Chase)

I dont see any scrubber channeling if its packed properly, surely thats the point.

The settlement isnt going to take place during the dive its going to occur in the car on the way there and on the boat on the journy out

A vertical scrubber is surely less likley to suffer this than a horizontal one?

It seems logical to me.

But hey i could be talking out of my arse.

ATB

Mark

i dont think you are talking out your arse (for a change

) when its strapped to the tank stands on a boat, (as it will be on any decent boat) i would not have my Rebreather stuffed under the bench while on the way out to a dive site.

it is however better while laying down in the boot of the car, going over all the f'ign speed bumps in town!

6th December 2007, 16:13	#1 (permalink)
netmage Hello Kitty...... Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Dec 2005 Location: Coconut Creek, FL Posts: 353	Channeling - Defined...? Been following the discussions on CO2, scrubber packing etc.. and I'm a little confused... What exactly is channeling...? Is it physical 'gaps' in the scrubber bed; whereby gas can find the path of least resistance w/o being scrubbed through loose material...? Or is it chemical 'gaps' in the scrubber bed; as in the repacking case, whereby gas finds a path thru used material in the scrubber bed...? -Tim (I pick up my meg tomorrow, class starts 1/24....)
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6th December 2007, 16:22	#2 (permalink)
Mark Chase I go down for ages Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Jan 2005 Location: Kent Posts: 2,470	Re: Channeling - Defined...? Quote: (Originally Posted by netmage) Been following the discussions on CO2, scrubber packing etc.. and I'm a little confused... What exactly is channeling...? Is it physical 'gaps' in the scrubber bed; whereby gas can find the path of least resistance w/o being scrubbed through loose material...? Or is it chemical 'gaps' in the scrubber bed; as in the repacking case, whereby gas finds a path thru used material in the scrubber bed...? -Tim (I pick up my meg tomorrow, class starts 1/24....) Spot on Settlement of the scrubber in a horizontal position may leave a loose fill or even a physical hole up the side of a scrubber (something the design of the rEvo scrubber seems more prone to IMHO) Mainly its clumping of the sorb or something like the repacking incident which leaves a path through the scrubber of spent lime. Whilst the path may be small C02 has a cumulative effect so will gradually build up during the dive. ATB Mark __________________ Is it supposed to make that noise ? I took my unit to the dive shop and demanded they bolt on every thing that would fit. Join my elite diving teem and get a Tshirt "Doing It Chasey"Hammerhead Eccr Advanced Diving System
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6th December 2007, 16:39	#3 (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: 1,384	Re: Channeling - Defined...? Quote: (Originally Posted by Mark Chase) Settlement of the scrubber in a horizontal position may leave a loose fill or even a physical hole up the side of a scrubber (something the design of the rEvo scrubber seems more prone to IMHO) uh?? hi Marc, where do you get that?? I think it is just the unit with the least possible chance for channeling: the only thing that can happen is that with heavy bumping the sorb would get more compacted towards the bottom of the scrubber! remember in horizontal position the gasflow trough the scrubber is vertical! regards 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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6th December 2007, 17:26	#4 (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: 2,817	Re: Channeling - Defined...? Quote: (Originally Posted by Mark Chase) Spot on Settlement of the scrubber in a horizontal position may leave a loose fill or even a physical hole up the side of a scrubber (something the design of the rEvo scrubber seems more prone to IMHO) Mainly its clumping of the sorb or something like the repacking incident which leaves a path through the scrubber of spent lime. Whilst the path may be small C02 has a cumulative effect so will gradually build up during the dive. ATB Mark Mark, sorry to say this but you are talking through your arse.. The each rEVo scruber is relatively short so packing is quite easy.. if you follow the proper packing procedure it packs very quickly and consistently.. if there is any settling (very doubtful if you follow the packing procedure) the spring could easily take up any space that has formed.. the short length probably makes it one of the most consitent scrubbers to pack and having 2 scrubbers make it highly unlikely that there will be a single path in BOTH scrubers to let gas bypass.... __________________ 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 : 6th December 2007 at 19:03.
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6th December 2007, 18:25	#5 (permalink)
decoweenie Crash Test Dummy Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Feb 2005 Location: Cairo Posts: 5,510	Re: Channeling - Defined...? Quote: (Originally Posted by jradomski) Mark, sorry to say this but you are talking through your arse.. Oh come on, Joe! Are you telling me that Mark Chase is talking thru his arse... ... again ?
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6th December 2007, 18:38	#6 (permalink)
sfldiver Team Optima Diver Current Rebreather/s: Optima Other Rebreather/s: Join Date: Jul 2007 Location: Pompano Beach, FL Posts: 664	Re: Channeling - Defined...? Gotta love those EAC's my Optima uses! And Tim, congrats on teh Meg purchase! I'm looking forward to seeing you out there with us on a Florida S.C.R.U.B. dive blowing no bubbles! Adrian __________________ *Currently piloting & shooting...* Dive Rite O2ptima FX Rigged w/ a Dsix Custom Aluminum Frame, Nomad Wing, Transpac Harness and VR3 Computer w/ VPM-B/E & a 4th Cell Sensor Link.* Canon PowerShot G9 Digital Camera *Rigged in a Patima-PDCH 2008 G9 Aluminum Housing w/ an Inon UWL-100 Achromat Wide Conversion Lens, 2 Inon UCL-165M67 Close-Up Lenses and 2 Inon Z-240 Strobes.
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6th December 2007, 18:48	#7 (permalink)
AD_ward9 So much more to learn Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Jun 2005 Location: Scotland Posts: 1,605	Re: Channeling - Defined...? Joe and Mark: you are both right. Mark's definition is the correct one of channelling. Many axial scrubbers suffer badly from channelling when the scrubber is horizontal. Joe rightly points out that the rEvo is not as prone to channelling as most axial scrubbers are, because it is oriented vertically when the diver is prone, and also has opportunity for the gas to mix between the two scrubbers, so raw unscrubbed gas does not go through a channel on the second scrubber even if both were to channel. However, I would like to see the figures for when the diver is vertical, such as in a deco reading his fishing journal or whatever he gets put onto the trapeze for amusement. Alex
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6th December 2007, 19:08	#8 (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: 2,817	Re: Channeling - Defined...? Quote: (Originally Posted by AD_ward9) Joe and Mark: you are both right. Mark's definition is the correct one of channelling. Many axial scrubbers suffer badly from channelling when the scrubber is horizontal. Joe rightly points out that the rEvo is not as prone to channelling as most axial scrubbers are, because it is oriented vertically when the diver is prone, and also has opportunity for the gas to mix between the two scrubbers, so raw unscrubbed gas does not go through a channel on the second scrubber even if both were to channel. However, I would like to see the figures for when the diver is vertical, such as in a deco reading his fishing journal or whatever he gets put onto the trapeze for amusement. Alex Alex, I really don't see the rEvo channeling.. When you following the packing procedure, the amount of sorb you is is very consistent.. so once you get the technque down there is very little variation from scrubber to scrubber.. so I see you either pack it really badly (probably by not having someone show you the technique) and you have a loose fill on many dives or you get a good fill.. Following the techniques that are taught in the class, I havent seen a poorly packed scrubber yet.. __________________ 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 : 6th December 2007 at 19:11.
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6th December 2007, 19:25	#9 (permalink)
Mark Chase I go down for ages Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Jan 2005 Location: Kent Posts: 2,470	Re: Channeling - Defined...? I dont see any scrubber channeling if its packed properly, surely thats the point. The settlement isnt going to take place during the dive its going to occur in the car on the way there and on the boat on the journy out A vertical scrubber is surely less likley to suffer this than a horizontal one? It seems logical to me. But hey i could be talking out of my arse. ATB Mark __________________ Is it supposed to make that noise ? I took my unit to the dive shop and demanded they bolt on every thing that would fit. Join my elite diving teem and get a Tshirt "Doing It Chasey"Hammerhead Eccr Advanced Diving System Last edited by Mark Chase : 6th December 2007 at 20:43.
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6th December 2007, 22:21	#10 (permalink)
ReikiMaster CK #21 Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Feb 2005 Location: Reading Berkshire Posts: 155	Re: Channeling - Defined...? Quote: (Originally Posted by Mark Chase) I dont see any scrubber channeling if its packed properly, surely thats the point. The settlement isnt going to take place during the dive its going to occur in the car on the way there and on the boat on the journy out A vertical scrubber is surely less likley to suffer this than a horizontal one? It seems logical to me. But hey i could be talking out of my arse. ATB Mark i dont think you are talking out your arse (for a change ) when its strapped to the tank stands on a boat, (as it will be on any decent boat) i would not have my Rebreather stuffed under the bench while on the way out to a dive site. it is however better while laying down in the boot of the car, going over all the f'ign speed bumps in town!
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