Would an integrated O2 tank pressure monitor be safer?

chrisp · 19th March 2008, 04:08

The fatality that occurred this past weekend got me thinking on this subject....

Considering the severe consequences that result if the oxygen is not turned on (either by user error, roll off, or 3rd party interference) why has a preventative/protective measure not been taken in Rebreather design?

It seems like it would be very easy to add an electronic (wired or wireless) pressure transducer to the first stage of the oxygen regulator. This pressure transducer would feed supply pressure info to computer/electronics. If the tank pressure dropped below a preset value (say 500 psi) or droped at too fast a rate, the electronics could trigger an alarm (such as vibrating the mouthpiece) to alert the diver. This would alert the diver to the problem prior to them becoming hypoxic and suffering any mental imparement.

I'm no electronics engineer but I'm sure this would not be difficult to implement.

I know that a diver should be checking his valves before a dive and not relying on a computer to save him, but accidents/oversights/complacency/etc. does happen. I think that a system like this could/would save lives.

What do you all think? Has this been thought of before? Is there a downside that I am missing? (Yeah, one more failure point, but I think the reward well outweighs the risk.)

***ScubaDadMiami*** · 19th March 2008, 05:01

I think that this is a good idea for not only O2 but also for diluent. It might not create a new failure point since it could replace the analog gauges that not only connect into the first stage (failure point one) but also have o-ring swivels (failure point two) and then connect into the SPG (failure point three).

Regarding the alarm, it would be important to make such a device so that the user would know right away which alarm was sounding. Too many alarms that go off in a similar fashion can be confusing and cause the diver to spend time trying to figure out what is going on rather than reacting.

***jradomski*** · 19th March 2008, 05:06

Quote: (Originally Posted by ScubaDadMiami)

I think that this is a good idea for not only O2 but also for diluent. It might not create a new failure point since it could replace the analog gauges that not only connect into the first stage (failure point one) but also have o-ring swivels (failure point two) and then connect into the SPG (failure point three).

Regarding the alarm, it would be important to make such a device so that the user would know right away which alarm was sounding. Too many alarms that go off in a similar fashion can be confusing and cause the diver to spend time trying to figure out what is going on rather than reacting.

this would not be a problem for oxgen asside from cost.. for diluent unless you go to an expensive capacitive sensor you will have issues with helium screwing up the pressure readings after a period of time..

Drmike · 19th March 2008, 05:11

Quote: (Originally Posted by chrisp)

The fatality that occurred this past weekend got me thinking on this subject....

Considering the severe consequences that result if the oxygen is not turned on (either by user error, roll off, or 3rd party interference) why has a preventative/protective measure not been taken in Rebreather design?

it has. Boris and Sentinel alarm will go off when O2 or Dil pressures drop to 50bar or anytime there is excessive usage rate. If tanks closed pressure will soon drop to zero and low pressure alarm and/or excessive usage rate alarm wll go off.

Drmike · 19th March 2008, 05:14

Quote: (Originally Posted by jradomski)

this would not be a problem for oxgen asside from cost.. for diluent unless you go to an expensive capacitive sensor you will have issues with helium screwing up the pressure readings after a period of time..

Hmm, are you sure about this?

Plenty of helium gas pressure sensors around, so far mine on Boris has been perfect (Ive used up to 90% He)

***jradomski*** · 19th March 2008, 05:44

Quote: (Originally Posted by Drmike)

Hmm, are you sure about this?

Plenty of helium gas pressure sensors around, so far mine on Boris has been perfect (Ive used up to 90% He)

yup... how screwed up it gets depends on the type of sensor and where the reference chamber is... if its a sealed absolute pressure sensors it will become inaccurate pretty quickly as there is only a ver small reference chamber.. if ts a differential sensor in a larger (or open) chamber, it will take longer to get screwed up (or not)... under stress the he molecule can diffuse across the stressed membrane (typical strain type sensor).. More expensive capacitive sensors can be used..

Pressure sensors like those used in mixing panels generally have an open side of the sensor so they would not see a problem, its primarily devices that need to be sealed..

also teh price people pay for the boris, its a possibility that a capacitive sensor is used... WHen I researched this a while back, the cheapest usable solution I found was in the $700 price each in large quantity..

Mark Chase · 19th March 2008, 05:50

I can see an advantage in a Diluient presure sensor because that can run out without you noticing but whats the ponint of an 02 sensor? If your going to be oblivious to PP02 drop wont you be oblivious to 02 presure drop?

Dosent a PP02 alarm do the same thing?

ATB

Mark

jhaaja · 19th March 2008, 05:57

Quote: (Originally Posted by Mark Chase)

I can see an advantage in a Diluient presure sensor because that can run out without you noticing but whats the ponint of an 02 sensor? If your going to be oblivious to PP02 drop wont you be oblivious to 02 presure drop?

Dosent a PP02 alarm do the same thing?

ATB

Mark

I agree, if you monitor your ppO2 you will notice that no O2 is being added. If you run out of diluent, it should not be too big a problem if you have bail out gas to use.

JH

Brainx3 · 19th March 2008, 06:04

Hi,

I already use that on my Inspiration. I have taken away the analog guages on my tanks and I have wireless guage integrated in my mask as I use Oceanic Data Mask which gives me a direct view all the time of my gases in addition to many other information.

Best Regards. Wael

***caveseeker7*** · 19th March 2008, 06:14

Quote: (Originally Posted by chrisp)

Has this been thought of before? Is there a downside that I am missing? (Yeah, one more failure point, but I think the reward well outweighs the risk.)

Before Closed Circuit Research's Ouroboros and Sentinel CCRs that technology was used in the Cis-Lunar MK-5p, not only for the O2 and dil inside the case, but with optional pressure transducer also the two tanks that can be mounted on the outside.

DeltaP offers a version of the Universal Rebreather Monitor that reads a single cell and two HP transducers. Can either be used with a 4th cell, or replace one of the stock displays.

So the technology is there, but it's expensive, and I gather there aren't too many takers of this version of the URM. The triple sensor version without the HP links is more popular as Jetsam offers it as a factory option.

One thing though, as any display and warning, it'll only do good if you watch and heed it.

19th March 2008, 04:08	#1 (permalink)
chrisp New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Nov 2007 Location: S.W. Florida Posts: 12	Would an integrated O2 tank pressure monitor be safer? The fatality that occurred this past weekend got me thinking on this subject.... Considering the severe consequences that result if the oxygen is not turned on (either by user error, roll off, or 3rd party interference) why has a preventative/protective measure not been taken in Rebreather design? It seems like it would be very easy to add an electronic (wired or wireless) pressure transducer to the first stage of the oxygen regulator. This pressure transducer would feed supply pressure info to computer/electronics. If the tank pressure dropped below a preset value (say 500 psi) or droped at too fast a rate, the electronics could trigger an alarm (such as vibrating the mouthpiece) to alert the diver. This would alert the diver to the problem prior to them becoming hypoxic and suffering any mental imparement. I'm no electronics engineer but I'm sure this would not be difficult to implement. I know that a diver should be checking his valves before a dive and not relying on a computer to save him, but accidents/oversights/complacency/etc. does happen. I think that a system like this could/would save lives. What do you all think? Has this been thought of before? Is there a downside that I am missing? (Yeah, one more failure point, but I think the reward well outweighs the risk.) __________________ http://www.whatisea.com
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19th March 2008, 05:01	#2 (permalink)
*ScubaDadMiami* Moderator Current Rebreather/s: Optima Other Rebreather/s: Join Date: Sep 2005 Location: Florida, USA Posts: 1,896	Re: Would an integrated O2 tank pressure monitor be safer? I think that this is a good idea for not only O2 but also for diluent. It might not create a new failure point since it could replace the analog gauges that not only connect into the first stage (failure point one) but also have o-ring swivels (failure point two) and then connect into the SPG (failure point three). Regarding the alarm, it would be important to make such a device so that the user would know right away which alarm was sounding. Too many alarms that go off in a similar fashion can be confusing and cause the diver to spend time trying to figure out what is going on rather than reacting. __________________ Howard Packer IANTD CCR Instructor Miami Beach, Florida CCRDiveTraining.com
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19th March 2008, 05:06	#3 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Home Build Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Home Build Join Date: Mar 2005 Location: "Da" Bronx Posts: 2,798	Re: Would an integrated O2 tank pressure monitor be safer? Quote: (Originally Posted by ScubaDadMiami) I think that this is a good idea for not only O2 but also for diluent. It might not create a new failure point since it could replace the analog gauges that not only connect into the first stage (failure point one) but also have o-ring swivels (failure point two) and then connect into the SPG (failure point three). Regarding the alarm, it would be important to make such a device so that the user would know right away which alarm was sounding. Too many alarms that go off in a similar fashion can be confusing and cause the diver to spend time trying to figure out what is going on rather than reacting. this would not be a problem for oxgen asside from cost.. for diluent unless you go to an expensive capacitive sensor you will have issues with helium screwing up the pressure readings after a period of time.. __________________ 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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19th March 2008, 05:11	#4 (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: 3,108	Re: Would an integrated O2 tank pressure monitor be safer? Quote: (Originally Posted by chrisp) The fatality that occurred this past weekend got me thinking on this subject.... Considering the severe consequences that result if the oxygen is not turned on (either by user error, roll off, or 3rd party interference) why has a preventative/protective measure not been taken in Rebreather design? it has. Boris and Sentinel alarm will go off when O2 or Dil pressures drop to 50bar or anytime there is excessive usage rate. If tanks closed pressure will soon drop to zero and low pressure alarm and/or excessive usage rate alarm wll go off. __________________ 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
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19th March 2008, 05:14	#5 (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: 3,108	Re: Would an integrated O2 tank pressure monitor be safer? Quote: (Originally Posted by jradomski) this would not be a problem for oxgen asside from cost.. for diluent unless you go to an expensive capacitive sensor you will have issues with helium screwing up the pressure readings after a period of time.. Hmm, are you sure about this? Plenty of helium gas pressure sensors around, so far mine on Boris has been perfect (Ive used up to 90% He) __________________ 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
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19th March 2008, 05:44	#6 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Home Build Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Home Build Join Date: Mar 2005 Location: "Da" Bronx Posts: 2,798	Re: Would an integrated O2 tank pressure monitor be safer? Quote: (Originally Posted by Drmike) Hmm, are you sure about this? Plenty of helium gas pressure sensors around, so far mine on Boris has been perfect (Ive used up to 90% He) yup... how screwed up it gets depends on the type of sensor and where the reference chamber is... if its a sealed absolute pressure sensors it will become inaccurate pretty quickly as there is only a ver small reference chamber.. if ts a differential sensor in a larger (or open) chamber, it will take longer to get screwed up (or not)... under stress the he molecule can diffuse across the stressed membrane (typical strain type sensor).. More expensive capacitive sensors can be used.. Pressure sensors like those used in mixing panels generally have an open side of the sensor so they would not see a problem, its primarily devices that need to be sealed.. also teh price people pay for the boris, its a possibility that a capacitive sensor is used... WHen I researched this a while back, the cheapest usable solution I found was in the $700 price each in large quantity.. __________________ 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. Last edited by jradomski : 19th March 2008 at 05:51.
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19th March 2008, 05:50	#7 (permalink)
Mark Chase I go down for ages Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Jan 2005 Location: Kent Posts: 2,417	Re: Would an integrated O2 tank pressure monitor be safer? I can see an advantage in a Diluient presure sensor because that can run out without you noticing but whats the ponint of an 02 sensor? If your going to be oblivious to PP02 drop wont you be oblivious to 02 presure drop? Dosent a PP02 alarm do the same thing? ATB Mark __________________ Is it supposed to make that noise ? I took my unit to the dive shop and demanded they bolt on every thing that would fit. Join my elite diving teem and get a Tshirt "Doing It Chasey"Hammerhead Eccr Advanced Diving System
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19th March 2008, 05:57	#8 (permalink)
jhaaja Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Mar 2005 Location: Finland Posts: 867	Re: Would an integrated O2 tank pressure monitor be safer? Quote: (Originally Posted by Mark Chase) I can see an advantage in a Diluient presure sensor because that can run out without you noticing but whats the ponint of an 02 sensor? If your going to be oblivious to PP02 drop wont you be oblivious to 02 presure drop? Dosent a PP02 alarm do the same thing? ATB Mark I agree, if you monitor your ppO2 you will notice that no O2 is being added. If you run out of diluent, it should not be too big a problem if you have bail out gas to use. JH
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19th March 2008, 06:04	#9 (permalink)
Brainx3 Temporary Read only mode for site infractions Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Join Date: Aug 2007 Location: Borås, Sweden Posts: 274	Re: Would an integrated O2 tank pressure monitor be safer? Hi, I already use that on my Inspiration. I have taken away the analog guages on my tanks and I have wireless guage integrated in my mask as I use Oceanic Data Mask which gives me a direct view all the time of my gases in addition to many other information. Best Regards. Wael
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19th March 2008, 06:14	#10 (permalink)
*caveseeker7* Who loves ya, baby Current Rebreather/s: Sport Kiss Other Rebreather/s: Prism Topaz Join Date: Jan 2005 Location: Too far from Neverland Posts: 5,287	Re: Would an integrated O2 tank pressure monitor be safer? Quote: (Originally Posted by chrisp) Has this been thought of before? Is there a downside that I am missing? (Yeah, one more failure point, but I think the reward well outweighs the risk.) Before Closed Circuit Research's Ouroboros and Sentinel CCRs that technology was used in the Cis-Lunar MK-5p, not only for the O2 and dil inside the case, but with optional pressure transducer also the two tanks that can be mounted on the outside. DeltaP offers a version of the Universal Rebreather Monitor that reads a single cell and two HP transducers. Can either be used with a 4th cell, or replace one of the stock displays. So the technology is there, but it's expensive, and I gather there aren't too many takers of this version of the URM. The triple sensor version without the HP links is more popular as Jetsam offers it as a factory option. One thing though, as any display and warning, it'll only do good if you watch and heed it. __________________ Cheers Stefan Be Water, My Friend - Bruce Lee Sponsor Lou in Race For Life!
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