Please Explain Scrubbers!

divemasterrob

Regarding the setup of Inspiration Scrubber units... I ACCEPT the fact that the unit was designed to insulate the Sofnolime from the cold water by use of an air cavity. I am new to rebreathers and am puzzled about the resulting impacts?
1. Why is the pack mounted on springs?
2. Don't they go BANG as a diver lands in the water, and cause the O ring to break it's seal?
3. The Spacer Collar above the O ring seats in a bevelled channel, so will it not be displaced, and leak, even momentarily? Gas would rush PAST the scrubber, fuelled by the gas wavefront created by the piston-like cannister throw on that spring!
4. Why are there not additional seals around the belly or middle portion of the scrubber walls, so an O ring there would always make contact with both surfaces, regardless of travel magnitude? These would keep the alignment correct thereby maintaining seal integrity.
5. Maybe there is no need to concern myself, as the CO2 is not kept on one side of the scrubber, but rather ABSORBED by the chemical reactions taking place in the material. But what about gas that bypasses the scrubber past the top O ring/collar seal?
Perhaps someone would be so kind as to share their experience with respect to the inevitable high impact (upon entries) on the scrubber for lets say a typical "giant stride" for example?
6. How does the sprung Sofnolime Cannister not slop around?
7. If water were to collect in the scrubber, then if inverted, would be allowed to wet the wiring, cells etc. So why is there not a watertight seal around the scrubber cannster? This would require ingress via the scrubber material itself, thereby maintaining vital function to continue unhindered.
8. Why is there not a water sensor in teh bottom of the scrubber? It would be powered by it's own battery and simply activate a buzzer when the probes detect water level threshold.

Ferg3333

1. Why is the pack mounted on springs?

To keep the scrubber packed, it is a self packing design provided you put enough lime in....

2. Don't they go BANG as a diver lands in the water, and cause the O ring to break it's seal?

It is secured by 4 bolts???

3. The Spacer Collar above the O ring seats in a bevelled channel, so will it not be displaced, and leak, even momentarily? Gas would rush PAST the scrubber, fuelled by the gas wavefront created by the piston-like cannister throw on that spring!

The sping keeps everything nice and tight, the o ring is slightly lubed to allow movement when putting the electronics on, and while it sits on the springs keeping the lime packed.

4. Why are there not additional seals around the belly or middle portion of the scrubber walls, so an O ring there would always make contact with both surfaces, regardless of travel magnitude? These would keep the alignment correct thereby maintaining seal integrity.

seal is already mantained.


5. Maybe there is no need to concern myself, as the CO2 is not kept on one side of the scrubber, but rather ABSORBED by the chemical reactions taking place in the material. But what about gas that bypasses the scrubber past the top O ring/collar seal?

No gas will bypass if set up correctly, unless you dont pack the lime properly and you get unfiltered gas through

Perhaps someone would be so kind as to share their experience with respect to the inevitable high impact (upon entries) on the scrubber for lets say a typical "giant stride" for example?

No problems they have sold 12000 units

6. How does the sprung Sofnolime Cannister not slop around?

it is completely encased and the springs are stiff to provide upthrust against the head

7. If water were to collect in the scrubber, then if inverted, would be allowed to wet the wiring, cells etc. So why is there not a watertight seal around the scrubber cannster? This would require ingress via the scrubber material itself, thereby maintaining vital function to continue unhindered.

The unit was designed about 10 years ago. It is very hard to completely flood a inspiration and its one of the more flood tolerant units on the market, you have that seal using the oring if gas cant pass neither can water


8. Why is there not a water sensor in teh bottom of the scrubber? It would be powered by it's own battery and simply activate a buzzer when the probes detect water level threshold.[/quote]

not needed you would hear water ingress before that point. Esp since your exhalation lung would be full of water or you would hear gas escaping if you had a hole in the breathing hoses.

I would suggest if you are looking at moving to ccr, discussing what the pros and cons of each unit are and if possible trying a few on to see how they feel in water and then if ccr is for you. Try and get the book Mastering Rebreathers by Jeff B

divernate

How about you do an inspo course or any ccr course with a decent instructor and then ask some sensible questions.


Or build your own Rebreather!

Ferg3333

fair enough but at least then he'd understand how it works

jkaterenchuk

They seem like reasonable and well thought out questions to me.

Some reading had to have been done to even come up with such specific questions.

It would be a sad day if everyone had to pay and take a course just to get some questions answered.

John

ReikiMaster

especially if they then dont like the answer they get and want to change their unit.

diveoceanos

Ferg I think you are very generous in aswering the questions and at the same time you are a little sarcastic. These words my folk Ferg "How about you do an inspo course or any ccr course with a decent instructor and then ask some sensible questions." could have been writen in an other way and yet to give the same meaning. What you meant to write (I think) is: "probably an Inspo course with a certified instructor would answer a lot of these questions and a lot more in full details" Right?

Being an instructor myself I know that people come to a course with different backrounds and different mentalities. I particularly enjoy a class where people like to ask questions or even to question my opinion as this allows more discussion from which some people do get a benefit! Please do not take it as granded that other people would see the obvious! Because the obvious is a very subjective matter! I mean for some people the answers are obvious while for others are not. It would be a sad day if we characterise a question as insensible! There are no insensible questions! There are retoric questions and real questions. And believe me the worst questions are the ones that we never asked!

Nice answers BTW and excuse my if I was a little philosophical. It is only because I thought...

Dive safe.
Sotos

Ferg3333

I was not intentionally being sarcastic, I was just a little unsure as it was post number one he had made??

caveseeker7

Nothing wrong with the questions, just some of the answers IMHO.

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aainslie

I'll take a bash at it:

1. Why is the pack mounted on springs?

The spring works in conjunction with the lid. basically the lid pushes the packed cartridge down (via the spacer ring, which seals using the O ring in the groove) and the spring pushes back against that.

2. Don't they go BANG as a diver lands in the water, and cause the O ring to break it's seal?

There's too much friction in the system. And even if it did it'd jump right back into place.

3. The Spacer Collar above the O ring seats in a bevelled channel, so will it not be displaced, and leak, even momentarily? Gas would rush PAST the scrubber, fuelled by the gas wavefront created by the piston-like cannister throw on that spring!

Not going to move. And if it did briefly during a heavy G load, there might be a tiny piddle of gas, qucikle terminated. I view this as a seriously unlikely scenario.

4. Why are there not additional seals around the belly or middle portion of the scrubber walls, so an O ring there would always make contact with both surfaces, regardless of travel magnitude? These would keep the alignment correct thereby maintaining seal integrity.

This'd be gilding the lily. Works fine as it is.

5. Maybe there is no need to concern myself, as the CO2 is not kept on one side of the scrubber, but rather ABSORBED by the chemical reactions taking place in the material. But what about gas that bypasses the scrubber past the top O ring/collar seal?

Again, you're overextrapolating a non event.

Perhaps someone would be so kind as to share their experience with respect to the inevitable high impact (upon entries) on the scrubber for lets say a typical "giant stride" for example?

Nothing!

6. How does the sprung Sofnolime Cannister not slop around?

Friction

7. If water were to collect in the scrubber, then if inverted, would be allowed to wet the wiring, cells etc. So why is there not a watertight seal around the scrubber cannster? This would require ingress via the scrubber material itself, thereby maintaining vital function to continue unhindered.

There is - two layers of water repellent paper and 5 lbs of scrubber. You'd need a helluva flood to get past that into the electronics.

8. Why is there not a water sensor in teh bottom of the scrubber? It would be powered by it's own battery and simply activate a buzzer when the probes detect water level threshold.[/quote]

Too much complication for too little benefit.

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Andrew Ainslie