Scrubber Packing

UKSteve · 31st August 2006, 20:03

For those of you who do not subscribe to the Drogon Inspiration mailing list, Martin Parker has posted a salient and sobering message that looks like it comes from investigations into a number of fatalities. Much of it should not be new to existing users but what has gobsmacked me are his comments on scrubber packing.

Without permission I will not regurgitate it in full here but essentially he says :

1) Fill halfway ...tap until level.
2) Fill to top ...tap until level
3) put the scrim and spider on
4) screw the nut down until it touches the spider - don't keep tightening it.
5) Ensure the spider is level or just proud of the edge of the scrubber cartridge
... and thats it - job done!!

He says that to turn and tap until you cant tighten the nut further and until the slime is firm is wrong and will be more liable to channeling.

As the latter was how I have been taught on my course and how I seem to understand the majority of users do it I am stunned. Does anyone know where it comes from?

Steve

***jradomski*** · 31st August 2006, 21:59

Quote: (Originally Posted by UKSteve)

For those of you who do not subscribe to the Drogon Inspiration mailing list, Martin Parker has posted a salient and sobering message that looks like it comes from investigations into a number of fatalities. Much of it should not be new to existing users but what has gobsmacked me are his comments on scrubber packing.

Without permission I will not regurgitate it in full here but essentially he says :

1) Fill halfway ...tap until level.
2) Fill to top ...tap until level
3) put the scrim and spider on
4) screw the nut down until it touches the spider - don't keep tightening it.
5) Ensure the spider is level or just proud of the edge of the scrubber cartridge
... and thats it - job done!!

He says that to turn and tap until you cant tighten the nut further and until the slime is firm is wrong and will be more liable to channeling.

As the latter was how I have been taught on my course and how I seem to understand the majority of users do it I am stunned. Does anyone know where it comes from?

Steve

most sorb manufactures recommend the sorb be packed as tightly as possible without crushing the granules..

If you crush them then you will change the wob... You can usually get away with a loose pack on an Inspiration because the plate will compress the sorb.. I tried it with a loose pack for a while and on bumpy boat rides the sorb settled considerably.. I was using a dye based sorb and you could see that the scrubber was not being used evenly.. since then I have always packed tight myself and have never had any channeling issues..

All the packing is done by tapping, the "nut" is only tightened by friction.. (using the tip of the finger only).. this way there is no way to crush and overpack the sorb, its only what would normally settle through vibration..

I also know that using this method I consistently use the same amount of sorb.. (I have checked by weight using the same batch)

UKSteve · 31st August 2006, 22:02

Joe,
I follow all of that..it just seems that Martin is recommending almost no packing at all.. save for the levelling twice. Really can't see how its going to ensure no channelling after a bumpy boat ride.

Steve

Barrie Law · 31st August 2006, 23:04

Quote: (Originally Posted by UKSteve)

For those of you who do not subscribe to the Drogon Inspiration mailing list, Martin Parker has posted a salient and sobering message that looks like it comes from investigations into a number of fatalities. Much of it should not be new to existing users but what has gobsmacked me are his comments on scrubber packing.

Without permission I will not regurgitate it in full here but essentially he says :

1) Fill halfway ...tap until level.
2) Fill to top ...tap until level
3) put the scrim and spider on
4) screw the nut down until it touches the spider - don't keep tightening it.
5) Ensure the spider is level or just proud of the edge of the scrubber cartridge
... and thats it - job done!!

He says that to turn and tap until you cant tighten the nut further and until the slime is firm is wrong and will be more liable to channeling.

As the latter was how I have been taught on my course and how I seem to understand the majority of users do it I am stunned. Does anyone know where it comes from?

Steve

Hi Steve,
During a visit to the UK in June, diving out of Falmouth a few of us went to AP for a visit and Martin was kind enough to demonstrate the correct filling method for the Inspiration.
It was a surprise for us to see him follow the above listed method with practically no tapping of the scrubber, I have been filling my scrubber by this method since without incident and I have when appropriate mentioned this to other Inspiration divers who have all said that's not the way I was shown.

After some discussion with Martin Parker it emerged the scrubber does not require the Sofnolime to be tighly packed.

Helium mix's and especially Heliox make the scrubber more efficient not less.

Regards

***jradomski*** · 1st September 2006, 00:31

Quote: (Originally Posted by UKSteve)

Joe,
I follow all of that..it just seems that Martin is recommending almost no packing at all.. save for the levelling twice. Really can't see how its going to ensure no channelling after a bumpy boat ride.

Steve

It probably will work 99.9% of the time, I'm not willing to push that .1%.. It probably only makes a difference if the scrubber is pushed way out.. I did see differences in scrubbers with long times on it where the tightly packed unit was purple straight up the core but a looser unit did have SOME white within the mostly purple areas..

I do Agree with Martin that if it is overpacked problems can occur.. people who FORCIBLY pack down the scrubber will cause problems and his policy of not tightening it down would remove that chance..

I'll just countinually tap until no more settling occurs.. The nut just is used to bring the scrim/plate to the current position.. You can get a good solid pack without ever using force on the nut..

I was told by more than one person who did run tests on scrubbers that a tight pack (one that wasnt forcibly overpacked) had no significant difference in WOB compared to a loose pack..

dive2dive2000 · 1st September 2006, 03:54

Quote: (Originally Posted by Barrie Law)

Helium mix's and especially Heliox make the scrubber more efficient not less.

Regards

Please explain, this goes against everything and also everyone I have spoken too or wrote too, including every thread on RBW

***jradomski*** · 1st September 2006, 04:08

Quote: (Originally Posted by dive2dive2000)

Please explain, this goes against everything and also everyone I have spoken too or wrote too, including every thread on RBW

there is actually a navy report showing these results..

Helium has a much lower thermal capacity so it takes alot less calories to heat it up (less to rob from the scrubber), so it will be more efficient.. BUT the scrubber usefulness drops with depth (pressure).. remember cooler gas will always enter the scrubber (once the scrubber is working).. Even if you could totally insulate the exhaled gas from the diver to the scrubber the highest it would be was body core temp, the core of a scrubber is usually warmer than that

if you were to compare 2 scrubbers both at 100m.. one using air as a medium and 1 using He as a medium, the He one would do better, but if you compared both of these against performance at the surface, both woud be much shorter.

UKSteve · 1st September 2006, 05:25

.. so there seem to be three options:

1. "AP" Method - as explained in first post
2. Tap - Turn nut method until compaction ends (as it seems many do - and how I was taught by my instructor) for "firm pack" - as described by Joe above
3. A more compacted pack where nut is turned forcibly.

Any instructors out there teaching method 1??

Steve

dive2dive2000 · 1st September 2006, 14:05

Quote: (Originally Posted by jradomski)

there is actually a navy report showing these results..

Helium has a much lower thermal capacity so it takes alot less calories to heat it up (less to rob from the scrubber), so it will be more efficient.. BUT the scrubber usefulness drops with depth (pressure).. remember cooler gas will always enter the scrubber (once the scrubber is working).. Even if you could totally insulate the exhaled gas from the diver to the scrubber the highest it would be was body core temp, the core of a scrubber is usually warmer than that

if you were to compare 2 scrubbers both at 100m.. one using air as a medium and 1 using He as a medium, the He one would do better, but if you compared both of these against performance at the surface, both woud be much shorter.

Hi Joe,
I am lost, If the temp is the same why would depth play a role?

Barrie Law · 1st September 2006, 15:33

Quote from Martin Parker APDiving:

Overpacking of Scrubbers

Giving tours round the factory this year I have been showing owners how to fill canisters. When questioning them, it has become clear that many are over-filling the canister - presumably worried about channelling. The problem is, you increase the channelling problem by over-filling. Fill it half way, tap until it's level, fill it to the top, tap until it's level, put the scrim and spider on, screw the nut down until it touches the spider - don't keep tightening it. Ensure the spider is level or just proud of the edge of the scrubber cartridge and away you go.
If you over-fill, you will get headaches, you will get increased work of breathing and you will get channelling.

31st August 2006, 20:03	#1 (permalink)
UKSteve Steve Collard Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Jul 2005 Location: Weymouth, UK Posts: 600	Scrubber Packing - all out the window...? For those of you who do not subscribe to the Drogon Inspiration mailing list, Martin Parker has posted a salient and sobering message that looks like it comes from investigations into a number of fatalities. Much of it should not be new to existing users but what has gobsmacked me are his comments on scrubber packing. Without permission I will not regurgitate it in full here but essentially he says : 1) Fill halfway ...tap until level. 2) Fill to top ...tap until level 3) put the scrim and spider on 4) screw the nut down until it touches the spider - don't keep tightening it. 5) Ensure the spider is level or just proud of the edge of the scrubber cartridge ... and thats it - job done!! He says that to turn and tap until you cant tighten the nut further and until the slime is firm is wrong and will be more liable to channeling. As the latter was how I have been taught on my course and how I seem to understand the majority of users do it I am stunned. Does anyone know where it comes from? Steve Last edited by UKSteve : 31st August 2006 at 21:34.
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31st August 2006, 21:59	#2 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Join Date: Mar 2005 Location: "Da" Bronx Posts: 3,095	Re: Scrubber Packing - all out the window...? Quote: (Originally Posted by UKSteve) For those of you who do not subscribe to the Drogon Inspiration mailing list, Martin Parker has posted a salient and sobering message that looks like it comes from investigations into a number of fatalities. Much of it should not be new to existing users but what has gobsmacked me are his comments on scrubber packing. Without permission I will not regurgitate it in full here but essentially he says : 1) Fill halfway ...tap until level. 2) Fill to top ...tap until level 3) put the scrim and spider on 4) screw the nut down until it touches the spider - don't keep tightening it. 5) Ensure the spider is level or just proud of the edge of the scrubber cartridge ... and thats it - job done!! He says that to turn and tap until you cant tighten the nut further and until the slime is firm is wrong and will be more liable to channeling. As the latter was how I have been taught on my course and how I seem to understand the majority of users do it I am stunned. Does anyone know where it comes from? Steve most sorb manufactures recommend the sorb be packed as tightly as possible without crushing the granules.. If you crush them then you will change the wob... You can usually get away with a loose pack on an Inspiration because the plate will compress the sorb.. I tried it with a loose pack for a while and on bumpy boat rides the sorb settled considerably.. I was using a dye based sorb and you could see that the scrubber was not being used evenly.. since then I have always packed tight myself and have never had any channeling issues.. All the packing is done by tapping, the "nut" is only tightened by friction.. (using the tip of the finger only).. this way there is no way to crush and overpack the sorb, its only what would normally settle through vibration.. I also know that using this method I consistently use the same amount of sorb.. (I have checked by weight using the same batch) __________________ 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 : 1st September 2006 at 05:56.
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31st August 2006, 22:02	#3 (permalink)
UKSteve Steve Collard Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Jul 2005 Location: Weymouth, UK Posts: 600	Re: Scrubber Packing - all out the window...? Joe, I follow all of that..it just seems that Martin is recommending almost no packing at all.. save for the levelling twice. Really can't see how its going to ensure no channelling after a bumpy boat ride. Steve
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31st August 2006, 23:04	#4 (permalink)
Barrie Law Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Jun 2005 Location: Ireland Posts: 459	Re: Scrubber Packing - all out the window...? Quote: (Originally Posted by UKSteve) For those of you who do not subscribe to the Drogon Inspiration mailing list, Martin Parker has posted a salient and sobering message that looks like it comes from investigations into a number of fatalities. Much of it should not be new to existing users but what has gobsmacked me are his comments on scrubber packing. Without permission I will not regurgitate it in full here but essentially he says : 1) Fill halfway ...tap until level. 2) Fill to top ...tap until level 3) put the scrim and spider on 4) screw the nut down until it touches the spider - don't keep tightening it. 5) Ensure the spider is level or just proud of the edge of the scrubber cartridge ... and thats it - job done!! He says that to turn and tap until you cant tighten the nut further and until the slime is firm is wrong and will be more liable to channeling. As the latter was how I have been taught on my course and how I seem to understand the majority of users do it I am stunned. Does anyone know where it comes from? Steve Hi Steve, During a visit to the UK in June, diving out of Falmouth a few of us went to AP for a visit and Martin was kind enough to demonstrate the correct filling method for the Inspiration. It was a surprise for us to see him follow the above listed method with practically no tapping of the scrubber, I have been filling my scrubber by this method since without incident and I have when appropriate mentioned this to other Inspiration divers who have all said that's not the way I was shown. After some discussion with Martin Parker it emerged the scrubber does not require the Sofnolime to be tighly packed. Helium mix's and especially Heliox make the scrubber more efficient not less. Regards
(Offline)

1st September 2006, 00:31	#5 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Join Date: Mar 2005 Location: "Da" Bronx Posts: 3,095	Re: Scrubber Packing - all out the window...? Quote: (Originally Posted by UKSteve) Joe, I follow all of that..it just seems that Martin is recommending almost no packing at all.. save for the levelling twice. Really can't see how its going to ensure no channelling after a bumpy boat ride. Steve It probably will work 99.9% of the time, I'm not willing to push that .1%.. It probably only makes a difference if the scrubber is pushed way out.. I did see differences in scrubbers with long times on it where the tightly packed unit was purple straight up the core but a looser unit did have SOME white within the mostly purple areas.. I do Agree with Martin that if it is overpacked problems can occur.. people who FORCIBLY pack down the scrubber will cause problems and his policy of not tightening it down would remove that chance.. I'll just countinually tap until no more settling occurs.. The nut just is used to bring the scrim/plate to the current position.. You can get a good solid pack without ever using force on the nut.. I was told by more than one person who did run tests on scrubbers that a tight pack (one that wasnt forcibly overpacked) had no significant difference in WOB compared to a loose pack.. __________________ 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.
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1st September 2006, 03:54	#6 (permalink)
dive2dive2000 PRISM DIVER & LUVIN IT! Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Feb 2005 Location: Long Island, NY Posts: 795	Re: Scrubber Packing - all out the window...? Quote: (Originally Posted by Barrie Law) Helium mix's and especially Heliox make the scrubber more efficient not less. Regards Please explain, this goes against everything and also everyone I have spoken too or wrote too, including every thread on RBW __________________ Safe Diving, Martin
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1st September 2006, 04:08	#7 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Join Date: Mar 2005 Location: "Da" Bronx Posts: 3,095	Re: Scrubber Packing - all out the window...? Quote: (Originally Posted by dive2dive2000) Please explain, this goes against everything and also everyone I have spoken too or wrote too, including every thread on RBW there is actually a navy report showing these results.. Helium has a much lower thermal capacity so it takes alot less calories to heat it up (less to rob from the scrubber), so it will be more efficient.. BUT the scrubber usefulness drops with depth (pressure).. remember cooler gas will always enter the scrubber (once the scrubber is working).. Even if you could totally insulate the exhaled gas from the diver to the scrubber the highest it would be was body core temp, the core of a scrubber is usually warmer than that if you were to compare 2 scrubbers both at 100m.. one using air as a medium and 1 using He as a medium, the He one would do better, but if you compared both of these against performance at the surface, both woud be much shorter. __________________ 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.
(Offline)

1st September 2006, 05:25	#8 (permalink)
UKSteve Steve Collard Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Jul 2005 Location: Weymouth, UK Posts: 600	Re: Scrubber Packing .. so there seem to be three options: 1. "AP" Method - as explained in first post 2. Tap - Turn nut method until compaction ends (as it seems many do - and how I was taught by my instructor) for "firm pack" - as described by Joe above 3. A more compacted pack where nut is turned forcibly. Any instructors out there teaching method 1?? Steve
(Offline)

1st September 2006, 14:05	#9 (permalink)
dive2dive2000 PRISM DIVER & LUVIN IT! Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Feb 2005 Location: Long Island, NY Posts: 795	Re: Scrubber Packing - all out the window...? Quote: (Originally Posted by jradomski) there is actually a navy report showing these results.. Helium has a much lower thermal capacity so it takes alot less calories to heat it up (less to rob from the scrubber), so it will be more efficient.. BUT the scrubber usefulness drops with depth (pressure).. remember cooler gas will always enter the scrubber (once the scrubber is working).. Even if you could totally insulate the exhaled gas from the diver to the scrubber the highest it would be was body core temp, the core of a scrubber is usually warmer than that if you were to compare 2 scrubbers both at 100m.. one using air as a medium and 1 using He as a medium, the He one would do better, but if you compared both of these against performance at the surface, both woud be much shorter. Hi Joe, I am lost, If the temp is the same why would depth play a role? __________________ Safe Diving, Martin
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1st September 2006, 15:33	#10 (permalink)
Barrie Law Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Jun 2005 Location: Ireland Posts: 459	Re: Scrubber Packing Quote from Martin Parker APDiving: Overpacking of Scrubbers Giving tours round the factory this year I have been showing owners how to fill canisters. When questioning them, it has become clear that many are over-filling the canister - presumably worried about channelling. The problem is, you increase the channelling problem by over-filling. Fill it half way, tap until it's level, fill it to the top, tap until it's level, put the scrim and spider on, screw the nut down until it touches the spider - don't keep tightening it. Ensure the spider is level or just proud of the edge of the scrubber cartridge and away you go. If you over-fill, you will get headaches, you will get increased work of breathing and you will get channelling.
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