Are cells in Counterlung good enough for ECCR?

Mdemon

Has anyone tried accurate setpoint control using cells/solenoid in a counterlung?

I've been told the gas flow might be too inconsistent for good control, but would be interested to see if anyone's done it.

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www.southwestmafia.com

"small minds talk about people, Average Minds Talk About Events, GREAT MINDS TALK ABOUT IDEAS!"

The WRONG Attitude will get you killed.

"Once the agenda-monkeys and perfect-worlders have moved on, perhaps we can do some diving?"

Moray Brown

Get in contact with Dennis Vessey via Megalodon UK
He had a conversion to run a 4th cell in CL for the Meg via a VR3

paulraymaekers

the problem of hanging cells in the counterlungs, without special precaution is more of condensation and water on the cells, then of mixing

paul

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Marc T

I actually have cells hanging in the counterlung of one of my sidemount which have only one inhale CL.
All the condensation is in the counterlung ( need a small sponge inside )but there is no condensation at all ( !!! ) after two hours and half on the sensors themselves.
I must say that I have been initialy quite surprised but I think that as long as the sensor face dont touch the CL it self, youll have no prob.

I must admit that thats need further testing.

paulraymaekers

hello Marc, seen sensors in dolphins, IDA's, subm.., you must take care that the cells stay away from the CL walls

a special problem is when you have some free water in the CL, and when you vacuum the counterlung, the water is actually 'pressed' into the cell, both front and back: test it with a transparant bag: put a cell in and a spoon of water: then vacuum the bag and see what happens with the water

I noticed the problem in the beginning with the rEvo alfa's (serie I) we did not have the plastic protection under the cellgrid, and we often got water into the cells: the lung was 'wrapping' itself around the cells, when you suck the unit negative

regards
paul

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.... the earth is flat, Elvis is alive, and radial scrubbers give longer dwell time than axials...

Mdemon

Thank you everyone for your comments.

Can I ask more on the mixing thing though? Mounting cells high in an Inspiration CL is easy. But if I add the O2 solenoid at the bottom of the counterlung, will the gas path be regular enough for the setpoint controller? Will variations in breathing depth and rate affect this more than normal scrubber-mounted electronics?

I worry that the flow might not be good enough to mix the O2 quickly, meaning that the controller might over-shoot giving lots of small spikes.

Or that shallow breaths might circulate low PO2 gas while the controller keeps perfect setpoint in a little pocket in the CL.







(I have had two cells dangling effectively in an Inspiration Inhale counterlung for some time, and because it is a long CL, condensation hasn't been a problem. They were mounted in a very low tech plastic onion net. This seemed to stop the wrap issues mentioned.)

__________________
www.southwestmafia.com

"small minds talk about people, Average Minds Talk About Events, GREAT MINDS TALK ABOUT IDEAS!"

The WRONG Attitude will get you killed.

"Once the agenda-monkeys and perfect-worlders have moved on, perhaps we can do some diving?"

Marc T

Dont think its a problem, mix in the CL is very quick, perhaps the O2 injection being closed to the sensors avoid spike.
The variation of the CL volume certainly induce occasional variation in the accuracy but certainly not so far from the one in mean volume.
A safe and cheap "solution" is using a set point arround 1.0 to 1.2 so you dont care about spike.
But what I say hum?