Sealing Hydrophobic membrane to canister

Drmike · 6th February 2007, 01:46

Quote: (Originally Posted by Frankie Pellegrino)

Mike I'm not sure I understand what your writing. (so please correct me if I'm wrong)
If a flat o-ring was sandwiched on the top and bottom of the membrane it isn't making any more of a seal then if it's sandwiched on the side's .

Thats right (Didnt say it would) - but its a more professional way to do it as it cant fall out/move and doesnt require fiddling about to fit/remove. Im only suggesting its a 'neater' more pro way to effect a seal.

Quote:

The porex is very hydrophobic not water proof. In my opinion the o-ring or silicone would only stop a easy water flow under or over the membrane regardless of were it's installed.

Yes I know - did you forget about my post on boris forum early last year. I tested it for water flow when I first got it. Found it lacking, suggested it needed to be sealed and suggested an o-ring. The membrane is hydrophobic - but the water passed the top and bottom as there was no seal (then) as I reported.

Quote:

So if water got into the loop you wouldn't get a caustic drink from the inhalation side of the kit. Then you can clear the water from the exhalation counter lung. We agree the canister will work with a good amount of water in it. And that if it was flooded you could recover and stay on the loop. (WOB wouldn't be the best or if it came through the exhalation side

thats another problem)

Yup been there done that (around 800m? in Russel cave (sp)) Flood recovery was a sinch - just stayed horizontal and opened the opv - got all the water out instantly - but obviously sorb totally wet. Scrubber still scrubbed but WOB was very high - too high for swimming - doable -just if scootering. Didnt get any caustic even though a full flood - so it does its job very very well.

Quote:

What I'm not understanding is if you installed a flat o-ring like you stated it wouldn't make any difference then if it was installed on the side of the membrane.

I didnt say it would make a better seal - its just a more pro way to effect a seal there. O-rings (or in this case a flat seal ring) should as far as possible be 'captive' Personaly I think Silicon is the worst way.

Capt.Dan · 6th February 2007, 02:00

La franc, make sure you tell the post about color cordination. I know its important.

Lt. Dan

jeff h · 6th February 2007, 02:25

Quote: (Originally Posted by Drmike)

I didnt say it would make a better seal - its just a more pro way to effect a seal there. O-rings (or in this case a flat seal ring) should as far as possible be 'captive' Personaly I think Silicon is the worst way.

Is the surface of the Porex membrane smooth? (i.e. is it a good sealing surface)?

If not then running a bead of silicon around the top and bottom lip would fill in the pores. You could smooth with your finger and let dry before installing in the rig. After that it should be sealable with a flat gasket or o-ring.

Drmike · 6th February 2007, 06:35

Quote: (Originally Posted by jeff h)

Is the surface of the Porex membrane smooth? (i.e. is it a good sealing surface)?

If not then running a bead of silicon around the top and bottom lip would fill in the pores. You could smooth with your finger and let dry before installing in the rig. After that it should be sealable with a flat gasket or o-ring.

Bead of Silicon (in fact any silicon inside a loop is just asking for trouble in my experience) I picked enough out of my OPV check valves etc to know that. The last flood I had was from a piece of silicon (thats used to seal the opv into the CL) working its way into the OPV.

No need to get too carried away with sealing as its got to hold back practically no differential so seal doesnt have to be great.

6th February 2007, 01:46	#11 (permalink)
Drmike Custom Title Allowed! Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,128	Re: Sealing Hydrophobic membrane to canister Quote: (Originally Posted by Frankie Pellegrino) Mike I'm not sure I understand what your writing. (so please correct me if I'm wrong) If a flat o-ring was sandwiched on the top and bottom of the membrane it isn't making any more of a seal then if it's sandwiched on the side's . Thats right (Didnt say it would) - but its a more professional way to do it as it cant fall out/move and doesnt require fiddling about to fit/remove. Im only suggesting its a 'neater' more pro way to effect a seal. Quote: The porex is very hydrophobic not water proof. In my opinion the o-ring or silicone would only stop a easy water flow under or over the membrane regardless of were it's installed. Yes I know - did you forget about my post on boris forum early last year. I tested it for water flow when I first got it. Found it lacking, suggested it needed to be sealed and suggested an o-ring. The membrane is hydrophobic - but the water passed the top and bottom as there was no seal (then) as I reported. Quote: So if water got into the loop you wouldn't get a caustic drink from the inhalation side of the kit. Then you can clear the water from the exhalation counter lung. We agree the canister will work with a good amount of water in it. And that if it was flooded you could recover and stay on the loop. (WOB wouldn't be the best or if it came through the exhalation side thats another problem) Yup been there done that (around 800m? in Russel cave (sp)) Flood recovery was a sinch - just stayed horizontal and opened the opv - got all the water out instantly - but obviously sorb totally wet. Scrubber still scrubbed but WOB was very high - too high for swimming - doable -just if scootering. Didnt get any caustic even though a full flood - so it does its job very very well. Quote: What I'm not understanding is if you installed a flat o-ring like you stated it wouldn't make any difference then if it was installed on the side of the membrane. I didnt say it would make a better seal - its just a more pro way to effect a seal there. O-rings (or in this case a flat seal ring) should as far as possible be 'captive' Personaly I think Silicon is the worst way. __________________ Get a girlfriend you sad twat - a Rebreather is an unfaithful mistress - dont blind yourself to her faults just because she goes down on you
(Offline)

6th February 2007, 02:00	#12 (permalink)
Capt.Dan New Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Nov 2006 Location: nj Posts: 8	Re: Sealing Hydrophobic membrane to canister La franc, make sure you tell the post about color cordination. I know its important. Lt. Dan
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6th February 2007, 02:25	#13 (permalink)
jeff h New Member Current Rebreather/s: Megalodon Other CCR Home Build Other Rebreather/s: Other CCR Home Build Join Date: Feb 2006 Location: Michigan Posts: 89	Re: Sealing Hydrophobic membrane to canister Quote: (Originally Posted by Drmike) I didnt say it would make a better seal - its just a more pro way to effect a seal there. O-rings (or in this case a flat seal ring) should as far as possible be 'captive' Personaly I think Silicon is the worst way. Is the surface of the Porex membrane smooth? (i.e. is it a good sealing surface)? If not then running a bead of silicon around the top and bottom lip would fill in the pores. You could smooth with your finger and let dry before installing in the rig. After that it should be sealable with a flat gasket or o-ring.
(Offline)

6th February 2007, 06:35	#14 (permalink)
Drmike Custom Title Allowed! Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,128	Re: Sealing Hydrophobic membrane to canister Quote: (Originally Posted by jeff h) Is the surface of the Porex membrane smooth? (i.e. is it a good sealing surface)? If not then running a bead of silicon around the top and bottom lip would fill in the pores. You could smooth with your finger and let dry before installing in the rig. After that it should be sealable with a flat gasket or o-ring. Bead of Silicon (in fact any silicon inside a loop is just asking for trouble in my experience) I picked enough out of my OPV check valves etc to know that. The last flood I had was from a piece of silicon (thats used to seal the opv into the CL) working its way into the OPV. No need to get too carried away with sealing as its got to hold back practically no differential so seal doesnt have to be great. __________________ Get a girlfriend you sad twat - a Rebreather is an unfaithful mistress - dont blind yourself to her faults just because she goes down on you
(Offline)

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