P Port Pressure

Tom Rose · 20th June 2007, 03:37

Does anyone know how much pressure a P Port will hold. I do not mean the attachment to the bag, but the pressure a P Port Plug will hold.

TIA

dockterj · 20th June 2007, 04:09

Don't know that I've ever seen "real" numbers for that. My guess is that the port itself will hold a lot more pressure than the lung and that the failure mode is the port blowing out of the lung. As such it would be dependent on each installation (is the lung doubled up? how much is the p-port torqued down?).

Sounds like it's time for empirical data! Let's blow some lungs up!!!

jaap · 20th June 2007, 09:46

Quote: (Originally Posted by Tom Rose)

Does anyone know how much pressure a P Port will hold. I do not mean the attachment to the bag, but the pressure a P Port Plug will hold.

TIA

I use a p-port on my latest cell testing pot. Makes it easy and fast to just put it in and test the cells now and then.

When testing if it would work I never tried more than a 2 bar gradient and it held nicely. I normally only test up to ~0.8 bar overpressure.

Drmike · 20th June 2007, 10:06

Havent tested it or done calcs but just looking at the wall thickness Id be surprised if it couldnt do at least 10 bar

Locked/housed in position you may have more of an issue with the spring clip at higher pressures- but who knows without testing

Tom Rose · 20th June 2007, 11:17

Quote: (Originally Posted by jaap)

I use a p-port on my latest cell testing pot. Makes it easy and fast to just put it in and test the cells now and then.

When testing if it would work I never tried more than a 2 bar gradient and it held nicely. I normally only test up to ~0.8 bar overpressure.

Exactly what I had planned, thanks for the information.

Do you have a picture?

I will do mine today and send one.

Tom

jaap · 21st June 2007, 00:59

Quote: (Originally Posted by Tom Rose)

Exactly what I had planned, thanks for the information.

Do you have a picture?

I will do mine today and send one.

Tom

Don't have it at home, but will try thinking about taking a pic of it this weekend.

Testing another earlier setup I had a slight mishap that might be interesting. The manometer got stuck for some reason so I ended up putting the full IP on the pot. Since it was a clear plastic one made from a lab bottle it started to look "overinflated" and a second later it burst with a bang...
No worries though since it was in a closed fume hood (safety frist

).

But an OPV set just above the operating pressure might be a good thing to incorporate. Or slightly more complicated to use a dedicated regulator with an IP set at the planned operating pressure.

Tom Rose · 21st June 2007, 01:55

Quote: (Originally Posted by jaap)

Don't have it at home, but will try thinking about taking a pic of it this weekend.

Testing another earlier setup I had a slight mishap that might be interesting. The manometer got stuck for some reason so I ended up putting the full IP on the pot. Since it was a clear plastic one made from a lab bottle it started to look "overinflated" and a second later it burst with a bang...
No worries though since it was in a closed fume hood (safety frist

).

But an OPV set just above the operating pressure might be a good thing to incorporate. Or slightly more complicated to use a dedicated regulator with an IP set at the planned operating pressure.

Bet that was exciting. Thanks for the tips.

Tom

Corallaro · 21st June 2007, 08:11

Hi Tom

I use a p-port on my pressure-pot and at now it works ok
until 2 ata (1+1 bar)

Giovanni

Tom Rose · 21st June 2007, 11:52

Quote: (Originally Posted by Corallaro)

Hi Tom

I use a p-port on my pressure-pot and at now it works ok
until 2 ata (1+1 bar)

Giovanni

Nice setup,

I finished mine last night and will test it today and post pictures.

Tom

Tom Rose · 22nd June 2007, 13:40

I tested my setup this morning. Pressure test was fine. With a p plug I was able to go to 3 bar absolute or 2 bar gauge. More than enough to test any cells.

Parts list:

P port
2 2" ABS Pipe caps
1 piece of 2" ABS pipe
Silicone rubber gasket material
One tire gauge with vent
One 1/8" NPT male to tube fitting (this fits my Cressi O2 output system

I drilled out the end of the tire gauge, and threaded the end
I drilled and tapped two holes in the one pipe cap. !/4 & 1/8 NPT
I machined out the other cap to hold the P port.

It works perfectly.......is light and also works as a cell protector when not in the Cressi.

Thanks guys for your info.

My picture below.

Tom

20th June 2007, 03:37	#1 (permalink)
Tom Rose Still Learning Current Rebreather/s: Other CCR Home Build Other Rebreather/s: Prism Topaz Other CCR Home Build Join Date: Oct 2005 Location: USA,North Carolina Posts: 331	P Port Pressure Does anyone know how much pressure a P Port will hold. I do not mean the attachment to the bag, but the pressure a P Port Plug will hold. TIA __________________ The 50-50-90 rule: Anytime I have a 50-50 chance of getting something right, there's a 90% probability I'll get it wrong the first time. www.atlimp.com
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20th June 2007, 04:09	#2 (permalink)
dockterj New Member Current Rebreather/s: Other CCR Azimuth Other SCR Home Build Other Rebreather/s: Other CCR Azimuth Other SCR Home Build Join Date: Jun 2007 Location: Michigan Posts: 3	Re: P Port Pressure Don't know that I've ever seen "real" numbers for that. My guess is that the port itself will hold a lot more pressure than the lung and that the failure mode is the port blowing out of the lung. As such it would be dependent on each installation (is the lung doubled up? how much is the p-port torqued down?). Sounds like it's time for empirical data! Let's blow some lungs up!!!
(Offline)

20th June 2007, 09:46	#3 (permalink)
jaap Normal people worry me Current Rebreather/s: Classic Kiss Other CCR RB80 / Clone Ray Other SCR Home Build Other Rebreather/s: Other CCR RB80 / Clone Ray Other SCR Home Build Join Date: Jun 2005 Location: Stockholm Sweden Posts: 473	Re: P Port Pressure Quote: (Originally Posted by Tom Rose) Does anyone know how much pressure a P Port will hold. I do not mean the attachment to the bag, but the pressure a P Port Plug will hold. TIA I use a p-port on my latest cell testing pot. Makes it easy and fast to just put it in and test the cells now and then. When testing if it would work I never tried more than a 2 bar gradient and it held nicely. I normally only test up to ~0.8 bar overpressure. __________________ My initials: JAAP
(Offline)

20th June 2007, 10:06	#4 (permalink)
Drmike RBW Member 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: 3,378	Re: P Port Pressure Havent tested it or done calcs but just looking at the wall thickness Id be surprised if it couldnt do at least 10 bar Locked/housed in position you may have more of an issue with the spring clip at higher pressures- but who knows without testing __________________ Cave diving is a sport Wreck diving is a sport Diving in general is a sport 'Rebreather diving' is not a sport its the delusional obsession with a highly dangerous and often inappropriate piece of equipment
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20th June 2007, 11:17	#5 (permalink)
Tom Rose Still Learning Current Rebreather/s: Other CCR Home Build Other Rebreather/s: Prism Topaz Other CCR Home Build Join Date: Oct 2005 Location: USA,North Carolina Posts: 331	Re: P Port Pressure Quote: (Originally Posted by jaap) I use a p-port on my latest cell testing pot. Makes it easy and fast to just put it in and test the cells now and then. When testing if it would work I never tried more than a 2 bar gradient and it held nicely. I normally only test up to ~0.8 bar overpressure. Exactly what I had planned, thanks for the information. Do you have a picture? I will do mine today and send one. Tom __________________ The 50-50-90 rule: Anytime I have a 50-50 chance of getting something right, there's a 90% probability I'll get it wrong the first time. www.atlimp.com
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21st June 2007, 00:59	#6 (permalink)
jaap Normal people worry me Current Rebreather/s: Classic Kiss Other CCR RB80 / Clone Ray Other SCR Home Build Other Rebreather/s: Other CCR RB80 / Clone Ray Other SCR Home Build Join Date: Jun 2005 Location: Stockholm Sweden Posts: 473	Re: P Port Pressure Quote: (Originally Posted by Tom Rose) Exactly what I had planned, thanks for the information. Do you have a picture? I will do mine today and send one. Tom Don't have it at home, but will try thinking about taking a pic of it this weekend. Testing another earlier setup I had a slight mishap that might be interesting. The manometer got stuck for some reason so I ended up putting the full IP on the pot. Since it was a clear plastic one made from a lab bottle it started to look "overinflated" and a second later it burst with a bang... No worries though since it was in a closed fume hood (safety frist ). But an OPV set just above the operating pressure might be a good thing to incorporate. Or slightly more complicated to use a dedicated regulator with an IP set at the planned operating pressure. __________________ My initials: JAAP
(Offline)

21st June 2007, 01:55	#7 (permalink)
Tom Rose Still Learning Current Rebreather/s: Other CCR Home Build Other Rebreather/s: Prism Topaz Other CCR Home Build Join Date: Oct 2005 Location: USA,North Carolina Posts: 331	Re: P Port Pressure Quote: (Originally Posted by jaap) Don't have it at home, but will try thinking about taking a pic of it this weekend. Testing another earlier setup I had a slight mishap that might be interesting. The manometer got stuck for some reason so I ended up putting the full IP on the pot. Since it was a clear plastic one made from a lab bottle it started to look "overinflated" and a second later it burst with a bang... No worries though since it was in a closed fume hood (safety frist ). But an OPV set just above the operating pressure might be a good thing to incorporate. Or slightly more complicated to use a dedicated regulator with an IP set at the planned operating pressure. Bet that was exciting. Thanks for the tips. Tom __________________ The 50-50-90 rule: Anytime I have a 50-50 chance of getting something right, there's a 90% probability I'll get it wrong the first time. www.atlimp.com
(Offline)

21st June 2007, 11:52	#9 (permalink)
Tom Rose Still Learning Current Rebreather/s: Other CCR Home Build Other Rebreather/s: Prism Topaz Other CCR Home Build Join Date: Oct 2005 Location: USA,North Carolina Posts: 331	Re: P Port Pressure Quote: (Originally Posted by Corallaro) Hi Tom I use a p-port on my pressure-pot and at now it works ok until 2 ata (1+1 bar) Giovanni Nice setup, I finished mine last night and will test it today and post pictures. Tom __________________ The 50-50-90 rule: Anytime I have a 50-50 chance of getting something right, there's a 90% probability I'll get it wrong the first time. www.atlimp.com
(Offline)

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