intermittend pressure and deeper diving

divelermentov · 4th August 2006, 00:26

I understand that the intermittend pressure at the inspo is 7.5 bar.
Which would be ambient pressure at 65 meters.

If you want to dive deeper you will need an increased ambient pressure, however my solenoid tents to stuck shut if the intermitend pressure is increased.
Or do I miss something here

Or do I have to drive the unit manually when diving deeper ?

Please can someone enlighten me

Cheers
Christian

Gibbon · 4th August 2006, 00:30

Quote: (Originally Posted by divelermentov)

Or do I miss something here

You are missing the depth compensation.

Padowan · 4th August 2006, 00:54

Yep, the compensation. Basically, when you tune a first stage to give you 7.5 bar, it will give you 7.5bar above ambient pressure. Therefore on the sirface with no additional pressure the absolute pressure is 7.5bar - when you are at 65m, and there is a surrounding pressure of 7.5bar around you - the reg will have an absolute pressure of 15bar, or 7.5bar above ambient, hence your solenoid will still work fine!

(Caveat) the compensation may not be completely linear, but it's near enough.

***jradomski*** · 4th August 2006, 01:11

Quote: (Originally Posted by divelermentov)

I understand that the intermittend pressure at the inspo is 7.5 bar.
Which would be ambient pressure at 65 meters.

If you want to dive deeper you will need an increased ambient pressure, however my solenoid tents to stuck shut if the intermitend pressure is increased.
Or do I miss something here

Or do I have to drive the unit manually when diving deeper ?

Please can someone enlighten me

Cheers
Christian

regs are depth compensating, in fact I tend to have the IP set lower (usually around 7 bar) to reduce the overshoots typical of the AP controllers when diving deeper..

divelermentov · 4th August 2006, 01:43

thanks

that makes sense ( I knew I had a basic mistake in my argumentation, must be due to beieng head down all the day here in down under

)

Thanks again for emlighten me

Greetings from down under
Christian

RonMicjan · 4th August 2006, 05:51

its possible you were refering to data on the KISS style CCR's whose regulators must be blocked from compensating for depth. They keep the intermediate pressure the same throughout the water column. the drawback to this type of system is when the ambient pressure reaches the IP, (at depth) then the oxygen flow stops and manual doesnt work either, so a diver using this system attempting to go deeper (usually around the 300 foot mark, but this will be based on the IP the diver has chosen to give them the proper flow, which is also based on the IP) must have a second injection system, or do an occasional dil flush while below this depth to keep the PO2 up.

Your inspiration has none of the above issues.

4th August 2006, 00:26	#1 (permalink)
divelermentov Nutty dentist - uwdriller Current Rebreather/s: Inspiration Classic Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: Auckland Posts: 663	intermittend pressure and deeper diving I understand that the intermittend pressure at the inspo is 7.5 bar. Which would be ambient pressure at 65 meters. If you want to dive deeper you will need an increased ambient pressure, however my solenoid tents to stuck shut if the intermitend pressure is increased. Or do I miss something here Or do I have to drive the unit manually when diving deeper ? Please can someone enlighten me Cheers Christian __________________ May The Sorb Be With You
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4th August 2006, 00:30	#2 (permalink)
Gibbon Southern Monkey Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Aug 2005 Location: East Devon Posts: 224	Re: intermittend pressure and deeper diving Quote: (Originally Posted by divelermentov) Or do I miss something here You are missing the depth compensation.
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4th August 2006, 00:54	#3 (permalink)
Padowan RBW Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2005 Location: Exeter, UK. Posts: 524	Re: intermittend pressure and deeper diving Yep, the compensation. Basically, when you tune a first stage to give you 7.5 bar, it will give you 7.5bar above ambient pressure. Therefore on the sirface with no additional pressure the absolute pressure is 7.5bar - when you are at 65m, and there is a surrounding pressure of 7.5bar around you - the reg will have an absolute pressure of 15bar, or 7.5bar above ambient, hence your solenoid will still work fine! (Caveat) the compensation may not be completely linear, but it's near enough. __________________ Padowan The future's bright, the future's Yellow .....for now padowan.net - Latest Video: Scapa Flow Rebreather Diving
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4th August 2006, 01:11	#4 (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: 3,096	Re: intermittend pressure and deeper diving Quote: (Originally Posted by divelermentov) I understand that the intermittend pressure at the inspo is 7.5 bar. Which would be ambient pressure at 65 meters. If you want to dive deeper you will need an increased ambient pressure, however my solenoid tents to stuck shut if the intermitend pressure is increased. Or do I miss something here Or do I have to drive the unit manually when diving deeper ? Please can someone enlighten me Cheers Christian regs are depth compensating, in fact I tend to have the IP set lower (usually around 7 bar) to reduce the overshoots typical of the AP controllers when diving deeper.. __________________ 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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4th August 2006, 01:43	#5 (permalink)
divelermentov Nutty dentist - uwdriller Current Rebreather/s: Inspiration Classic Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: Auckland Posts: 663	Re: intermittend pressure and deeper diving thanks that makes sense ( I knew I had a basic mistake in my argumentation, must be due to beieng head down all the day here in down under ) Thanks again for emlighten me Greetings from down under Christian __________________ May The Sorb Be With You
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4th August 2006, 05:51	#6 (permalink)
RonMicjan Cap Ron scourge of the NW Current Rebreather/s: Megalodon Dolphin Home Build Other Rebreather/s: Sport Kiss Classic Kiss Dolphin Home Build Join Date: Feb 2005 Location: Cape Disapointment, The Graveyard of the Pacific Posts: 1,112	Re: intermittend pressure and deeper diving its possible you were refering to data on the KISS style CCR's whose regulators must be blocked from compensating for depth. They keep the intermediate pressure the same throughout the water column. the drawback to this type of system is when the ambient pressure reaches the IP, (at depth) then the oxygen flow stops and manual doesnt work either, so a diver using this system attempting to go deeper (usually around the 300 foot mark, but this will be based on the IP the diver has chosen to give them the proper flow, which is also based on the IP) must have a second injection system, or do an occasional dil flush while below this depth to keep the PO2 up. Your inspiration has none of the above issues. __________________ Marine rescue, towing and salvage. Interfering with natural selection since 1983. www.tmishop.com Diving bits etc. www.seatowpdx.com The Summer Job
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