caustic cocktail

Tom Mount · 18th May 2007, 20:02

Quote: (Originally Posted by AD_ward9)

There are three issues here:

1. Risks from hydrophobic pads. Which material would you use? All increase WOB, some a lot more than others, and if the user packs the material incorrectly, the result can be serious. The Stone Aerospace cartridges are not designed for the chaotic environment of sports diving, and some of the things sports divers do.

2. EACs with electronic flood detection are a solution. EACs take tens of minutes to reach dangerous pH levels, compared to 30 seconds with granules.

3. The granules themselves. Just a month ago there were posts explaining how it was not a clever idea to use medical grade granules, yet in this very sad accident, that is just what was used. If there is a CO2 hit before the flood, which is almost always the case, the diver cannot deal with it. Those granules were not appropriate for diving. There is widespread ignorance of what absorbers do with increasing levels of CO2 flow: many shut down giving huge CO2 spikes. Divers are doing these changes without the faintest idea of what it is they are actually doing. Training organisations have a role to explain this to their students: i.e. do NOT mess with granules other than those the unit has been designed for and tested with.

I had a complete flood and caustic cocktail on a rebreather 6 years ago due to a design fault on the equipment (that is still there on units sold today). The accident was enough for me to take a lot of interest in Micropore's products. The CO2 hit that goes with a flood makes one far less able to reason about a caustic cocktail. I thought it was caustic coming into my nose, but that was an hallucination under the CO2 hit - my nose was in a half mask. Fortunately I was very close to the surface, I did bail out - albeit much too slowly, and the boat came fast. If I had been deeper, I would have been gone.

As regards low risk not needing the investment: caustic cocktails are not low risk, not are they infrequent. The problem is caused by incompetent safety design IMHO.

Simon's post shows the critical nature of these failures, as do the accident lists, and posts such as yours, Rons and others, show it is not uncommon. I cannot see how on earth any manufacturer can defend not dealing with these issues. Perhaps manufacturers on the forum could enlighten us?

Alex

Hi Alex
Well first, there are several grades- and at least one manufacture is going to come out with it as an option in the near future

Second the Borus has it now and one of my friends is diving it

Third I already stated it would increase wOB- but that can be a minimum and for the safety well worth the effort

And Wow what you base your assumption on that the CIS Canister will not stand up to the abuse of sport divers

I have two cis canisters I have dived in the Meg since owning the meg other than pre production that threaded into canister- they have traveled around the world bent beat up by me- I do not baby equipment at al they work perfect I think a coupe of other people on this list are using them- a couple of my students have and are using them- So I think you are way off base- unfortunately they only work in the CIS and Meg or I would use them in everything. I do not think there is anything a sport diver could do to a canister I nor Joe nor Bill nor Rich nor any number of other peoiple have not and they still work- you do not know much about the historu of the cis canister and have some assumptions that are incorrect as to their durability. and over all toughness

I would lie to know more about the risk of the mebranes- the design to keep wOB down is important but what other risk do you refer to-

And where does one get an EAC and electronic warning-

I would chalenge your there was a co2 hit then the flood and caustic- most of the times i have seen caustic they were not preceeded by co2 issues - and the ones I have had mellow by comparision to some- happened quickly and I discoverd why but that did not keep them from happening. A bad cO2 hit will put you top sleep or render you unable torewact- in the cases of caustic I have seen this is not the case.

I think ALL training agencies emphasize use only sorb approved for the unit. People I know who got hits were using sorb or cartridges designed for the unit.

Yes, he was using med grade- but caustic is caustic and why not do something to avoid it- instead of finding a reason not to avoid it.

We completely agree that caustic is not a low rish although often it is perceived to be- Hope the manufactures including micropore will get interested .

And in closing pads can be designed to keep aminimum of WOB- and the cis is an excellent rugged design

Most units try to use water traps and that does a reasobable job but would be more efficient with a membrane to keep water out of the canister

At least you and others are interested and pushing to get a solution tell me more about the electronic warnings

AD_ward9 · 18th May 2007, 20:18

Hi Tom,

The electronic warnings we use are based on the differential pressure across the scrubber. It rises 3 to 4 fold in the case of granular scrubbers and more than 10 fold in the case of EACs when there is a flood, after compensating for gas and depth. Methods that simply measure the resistance between two isolated parts can also work: the condensation is relatively high resistance compared to a cocktail. My point was that manufacturers can address this issue if the will is there.

On the hydrophobic membranes, they are torn easily and in a general sports diving environment users would replace them with the wrong thing. On regular use, the pores get blocked. The materials are generally designed as surface filters, so they collect microscopic detritus. There are more than a dozen different hydrophobic membranes so I asked which material you had in mind so I could be specific. If we take as an example two materials which are quite similar, Zitex A105 and the GE Nylon equivalent, these have a high breathing resistance. The problem is to block water, but they resist gas. A 2lb/inch pressure in resisting water translates to tens of millibar in blocking gas. Moreover, when the membrane is wet, the resistance to gas increases dramatically. Some other membranes use PTFE, which introduces risk of off-gasing toxic products into the breathing loop. I agree the Stone canisters are particularly well designed, but in my view it is better to cure the problem at source.

On the CO2 hit, I was not referring to one that is so bad as to knock a diver out, but one that causes the diver to get confused or even hallucinate. When measuring scrubbers in the lab, when scrubbers are wet, they both increase breathing resistance and allow CO2 to spike. It was also my experience with a heavy flood: one is not conscious of one's judgement being affected but the hallucination is proof that it is severely.

Cheers,

Alex

Tom Mount · 19th May 2007, 11:02

Hi Alex

In all hypercapnia -hypoxia and hyperoxia the first real thing is confussion- So agree that with hypercapnia confussion comes first

Where I disagree is that not all floods cause hypercapnia as some happen fast- Most I have seen or experienced were very fast

A slow flood as on a dive would produce hypercapnia first and of course, it would all be down hill at that point.

In addition, most often one who has a CO2 hit has limited time to respond if they even become aware of the hit.

In your case it does sound as if you had a co2 hit c\with the flood- I imagine this was not the more or less explosive type caustic's I have seen.

The electronic warnings sounds like a great and relatively inexpensive way to go- and maybe in the long run the safest. I would definitely use such a system.

I do hope someone does produce either a safe hydrophobic membrane or the EEC

On the Cis canister yes it will clog thus one must (not should but must) rinse/clean it every 30 to 50 hours. As you know the Cis looks very much like a raycor fuel filter in a diesel engine-I often wonder if it is the same material.

Selection of a hydrophobiac material that provides low breathing resistance, is efficient and does not give off toxic gas (I did not know about the toxic gas issue before) would be a challenge for the manufactures.

So question how does one go about installing an electronic warning system into their individual rebreathers? I for one would like to have it on all unts if your testing reflects it is dependable and can be done eaisly

Most any unit can be flooded

When I fist got my Evolution a few years back it flooded the first 4 dives I did quickly- It would hold pos and neg overnight- I checked the mouthpeice it on the outside was good. As this is a source that has caused floods before by having small tears in them- not so in this case at least outwardly

But when I took the mouthpeice off- and looked on the inside that seals to the DSV it had a small gorove in it- so most likely a mold imperfection. Changed mouth pieces and it has not had an issue since that time- Also as these were fast (relatively ) floods I actually went upside down (did not inhale) and cleared the unit totally just as we do on the Cis and each time dived- The sorb in these cases when changed post dive were slightly damp not wet - and no taste and of course no caustic.

In fact I was delighted as on the old inspiration I had never been able to get water out of it -that had gooten into the canister housing - and on the evolution it is apeice of cake- but doing a clear of this nature does run a risk of caustic thus I do not teach it ( although of course we do/did on the Cis and until veryrecently I did on the Meg and on the Optima, but trick is it has tobe done at fist flood (notice of excessing breathing resostance -not after hearing "heavy" gurgling for a prolonged period of time- just teach clearing water out of CL or in some units water traps. I use the term "heavy" gurgling to reflect 3h difference in the gurgle in the exhalation hose that people get comfortable with and then do not notice the change in sound or type gurgle thus go on to flood the unit in some cases.

Anyway would love to explore the electronic warning systems - I fyou need test subjects in the field I for one would be a test subject)

Was just looking at Chris' Haveranero- it is about as flood proof as anything can be -the canister is bascially sealed in such a nmanner that unless water is emitted through the inhalation hose it cannot get to the canister- he even demonstrates taking a hose and running into the exhalation side and the water simply runs out-Very impressive- (it is a passive sCR) So that may be another solution to prevention of floods of the canister

Thanks for the info

AD_ward9 · 19th May 2007, 15:06

Quote: (Originally Posted by Tom Mount)

Was just looking at Chris' Haveranero- it is about as flood proof as anything can be -the canister is bascially sealed in such a nmanner that unless water is emitted through the inhalation hose it cannot get to the canister- he even demonstrates taking a hose and running into the exhalation side and the water simply runs out-Very impressive- (it is a passive sCR) So that may be another solution to prevention of floods of the canister

Hi Tom,

Your post was full of little gems. We will publish in full the flood monitoring details (the circuit is already published on the DL site). I will call to follow up with you on the testing at a suitable time.

On materials, if one is going down the hydrophobic membrane route, then PVDF (Kynar) membranes appear to be the safest. Kynar is a material we like for rebreather parts generally, as it is the purest synthetic resin available and is mouldable without softeners and plasticisers, as well as being very tough. The problem is primarily one of ensuring the users clean the membrane regularly or replace it, and ensuring the user cannot replace the membrane with something else such as by welding the membrane to a ring so they have to buy the ring and membrane as an assembly. These membranes are fragile in the micron thicknesses of hydrophobic membrane, but it is obvious when it is torn.

Your comment about Chri's Haveranero in particular has piqued my interest. Is there anywhere one can find more information?

Cheers,

Alex

Tom Mount · 19th May 2007, 15:09

For those not up on PH etc- you may like the following material and the info on the web page How You Rot & Rust

How You Rot & Rust

It all begins with pH.

THE pH REGULATORY SYSTEM OF THE BODY

The pH balance of the human bloodstream is recognized by all medical physiology texts as one of the most important biochemical balances in all of human body chemistry.

pH is the acronym for "Potential Hydrogen". In definition, it is the degree of concentration of hydrogen ions in a substance or solution. It is measured on a logarithmic scale from 0 to 14. Higher numbers means a substance is more alkaline in nature and there is a greater potential for absorbing more hydrogen ions. Lower numbers indicate more acidity with less potential for absorbing hydrogen ions.

Our body pH is very important because pH controls the speed of our body's biochemical reactions. It does this by controlling the speed of enzyme activity as well as the speed that electricity moves through our body.

The higher (more alkaline) the pH of a substance or solution, the more electrical resistance that substance or solution holds. Therefore, electricity travels slower with higher pH.

All biochemical reactions and electrical (life) energy
are under pH control.

If we say something has an acid pH, we are saying it is hot and fast. As an example, look at the battery of your car. It's an acid battery. On cold days you want it to be hot and ready, and you want your car to start fast.

Alkaline pHon the other hand, biochemically speaking, is slow and cool. Compare it to an alkaline battery in a flashlight. You want that battery to be cool, and to burn out slowly.

Here is an example of how pH can control. Look around you at society in general. Do you see people getting exhausted, burned out, and quick to anger? Do you see a rise in violence? In part it could be due to the fact that people today lean to an acid pH. As a society we are running hot and fast. How did we get there? We guzzle coffee for breakfast (acid), burgers for lunch (acid), wash it down with king size colas (acid), and have a pizza (acid) for dinner. In fact, with this scenario, you could easily correlate the rise of violence in our society with the increasing number of fast food restaurants on every corner. But I digress. However, this does lead me to the second part of the pH and digestive metabolic equation. pH is under the direct control of what we put into our mouths. Kind of makes sense doesn't it?

What we eat and drink will impact where our body's pH level falls, and our body's pH will control the activity of every metabolic function happening in our body.

pH is behind the body's electrical system and intracellular activity as well as the way our bodies utilize enzymes, minerals, and vitamins. That is why pH is one of the first things to be looked at if you are experiencing unbalance in your body in any way, shape, or form. And since our body's pH level is a direct result of what we eat and drink, anytime we are experiencing imbalance, we need to look at what we have historically been eating and drinking because this impacts our pH. It's a circle. You can't look at one without looking at the other.

What we eat and drink is directly tied to the functioning of our digestive system. From our mouth through our small intestines and through our colon, that system plays the most important part in our physical well being. This system, what we feed it, and how it impacts our pH, is the essential core that determines whether we have perfect health or not. It is really so simple.

Now you may be thinking that all of this makes perfect sense. It is so simple that you would think that modern medicine could look at it, put two and two together and simply attempt to bring people back into balance through the food that they eat.

Hippocrates said, "Let food be your medicine.
Let medicine be your food."

If it were only so simple. Modern medicine has gotten to where it is today in part through a scientific and philosophical debate that culminated in the 19th century. On one side of the debate was French microbiologist Antoine Bechamp. On the other side was French microbiologist Louis Pasteur. Bechamp and Pasteur strongly disagreed in their bacteriological theories. They argued heatedly about who was correct. It was...

The Argument that Changed the Course of Medicine.

Pasteur promoted a theory of disease that described non-changeable microbes as the primary cause of disease. This is the theory of monomorphism. This theory says that a microorganism is static and unchangeable. It is what it is. Disease is solely caused by microbes or bacteria that invade the body from the outside. (This is the germ theory.)

Bechamp held the view that microorganisms can go through different stages of development and they can evolve into various growth forms within their life cycle. This is the theory of pleomorphism. He observed microbe like particles in the blood which he called microzymas. These microbes would change shape as individuals became diseased, and for Bechamp, this was the cause of disease; hence disease comes from inside the body.

Another scientist of the day, Claude Bernard, entered into the argument and said that it was actually the "milieu" or the environment that is all important to the disease process. Microbes do change and evolve, but how they do so is a result of the environment (or terrain) to which they are exposed. Hence, for Bechamp, microbes, being pleomorphic, will change according to the environment to which they are exposed. Therefore, disease in the body, as a biological process, will develop and manifest dependent upon the state of the internal biological terrain. At the core of that terrain, is pH.

Both men acknowledged certain aspects of each other's research, but it Pasteur was the stronger, more flamboyant, and more vocal opponent when compared to the quiet Bechamp. Pasteur also came from wealth and had the right family connections. He went to great lengths to disprove Bechamp's view. Pasteur eventually managed to convince the scientific community that his view alone was correct. Bechamp felt that this diverted science down a deplorable road - a road that held only half the truth.

On his deathbed, Pasteur finally acknowledged Bechamp's work and said, "Bernard was correct: the microbe is nothing: the terrain is everything." It was a 180 degree turnaround. With his death imminently at hand, he as much as admitted that his germ theory had flaws. But his admission fell on deaf ears. It was far too late. It could not reverse the inertia of ideas that had already been accepted by mainstream science at that time. Allopathic (drug based) medicine was firmly entrenched on the road that was paved by Pasteur.

The result of that road is what you see today practiced as medicine. When a body is out of balance, doctors attempt to put it back into balance, first through drugs, then through surgery. The general effect is to remove the symptoms, not to deal with the ultimate cause of the ailment.

Please I have no intention of offending MD's this is just the material on the web page- even though as an ND I do agree in the treatment of cause rather than symptom- but all approaches have merit and time and place, I even recently had surgery due to it being a correct time and place- of course aftert two months replaced the meds with natural substances free of side effects- but this was a good page and has several other "chapters" on PH without getting into allot of biochemistry so all can understand and benefit from it.

Tom Mount · 19th May 2007, 15:25

Quote: (Originally Posted by AD_ward9)

Hi Tom,

Your post was full of little gems. We will publish in full the flood monitoring details (the circuit is already published on the DL site). I will call to follow up with you on the testing at a suitable time.

Your comment about Chri's Haveranero in particular has piqued my interest. Is there anywhere one can find more information?

Cheers,

Alex

Alex could you contact me at tom.mount@Chi-EnergyDynamics.com

You have my full attention with the electronic warning- althouh i still like the idea of a safe membrane so unit can be cleared and stayed on UM!- for me both sound good combined warning- abilty to prevent - and then use the techniques to clear all water from the system- What the heck if you are gonna ask for something ask BIG

Genesis · 19th May 2007, 19:55

There are two methods I can think of with regards to electronic warning.

The first is as Alex outlined - trigger on WOB changes. However, this may or may not give warning, depending on the nature of the flood (a swimmer in a horizontal position could potentially flood a good bit of an EAC cannister without impairing gas flow enough to trip the sensor, and if it sits in there long enough it'll stil nail you.)

The second however, appears to be just as valid if not more so, at least for an OTS design which requires that the cocktail get past the "T" piece on the inhale lung before it can get YOU. And that is to monitor for liquid intrusion at the exit of the cannister (inhale side) with a probe set that will trip an alarm on the handset and/or HUD when flooded.

This SHOULD give you enough warning of an impending disaster to bail, and it would work no matter how the cocktail got there. If you get liquid of a low enough conductivity on the probes the alarm goes off, and if the liquid must pass the probes to get into the inhale hose and counterlung, that should do it.

I will have to run some tests on this, but this appears to be pretty simple to do, because ordinary condensation (which of course is all over the inside of the unit in operation) should have MUCH higher resistance than a cocktail, which is full of ions and thus would have extremely low resistence.

Floods of the magnitude required to pass the 'sorb and emerge on the inhale side headed for your mouth would, I suspect, reliably trip a probe set.

What am I missing?

Drmike · 20th May 2007, 07:23

Boris has a hydrophobic membrane which (when sealed in with o-ring cord) will keep caustic away from the diver. MK15.5/16s also has membranes (like boris they need to be sealed at the edges)

It is very reasuring to know you can never have a coctail.

When the edges of the membranes werent sealed in both cases (boris and MK15.5) I was actually alerted to flooding by mild caustic taste - which gave me some warning.

Of course if you forget to close your mouthpiece when your shaking it over your head in an attempt to getting rid of hose girgles 800m+ inside a cave - you get what you deserve

, especially if the scooter decides to fail at the same time

AD_ward9 · 20th May 2007, 15:27

Quote: (Originally Posted by Genesis)

I will have to run some tests on this, but this appears to be pretty simple to do, because ordinary condensation (which of course is all over the inside of the unit in operation) should have MUCH higher resistance than a cocktail, which is full of ions and thus would have extremely low resistence.

Floods of the magnitude required to pass the 'sorb and emerge on the inhale side headed for your mouth would, I suspect, reliably trip a probe set.

What am I missing?

You are not missing anything Karl. If you measure less than 1K Ohm between two probes in the port from the head to the inhale bag then it is flooded.

To see the effect of a flood, just put multimeter probes into a cup of clean water and drop in some granules. As you say, there are so many ions the resistance drops really quick.

Alex

Outlaw · 20th May 2007, 17:36

hey guys,

is there a chance that you have some caustic fumes due to the scruber being wet and then to continue the dive breathing from the loop?

i once had an incident where i was under for about 2 hours, and suddenly i felt like throwing up, which i did. i managed to to shut the DVS valve and when on the bail out, had a five minute breathing on that, which was air, and then went back on the loop and i could still manage to finish the dive, well i had a scooter battery running out so i had a long swim.

This was last year by the way. at the time i was thinking that it was due to the fact that during the dive i was increasing and decreasing my set point on 02, but when i came home, i realized that my scrubber was sort of "half wet".... i have the pictures somewhere....i'll try and find them and post.

it was really strange for me, especially now that i read all these posts, but there was no clarification if a scrubber can actually get wet, and have no issues with the dive....can this thing happen, or once water touches the sofnolime then is all over.

Please advice. i would like to hear your views. promise to sent the pictures which will help you realize what i mean.

Chees.

Spyros.

18th May 2007, 20:02	#31 (permalink)
Tom Mount New Member Current Rebreather/s: Inspiration Classic Evolution Megalodon Sport Kiss Classic Kiss Optima Other CCR Other Rebreather/s: Other CCR Join Date: Jul 2005 Location: USA Posts: 96	Re: caustic cocktail Quote: (Originally Posted by AD_ward9) There are three issues here: 1. Risks from hydrophobic pads. Which material would you use? All increase WOB, some a lot more than others, and if the user packs the material incorrectly, the result can be serious. The Stone Aerospace cartridges are not designed for the chaotic environment of sports diving, and some of the things sports divers do. 2. EACs with electronic flood detection are a solution. EACs take tens of minutes to reach dangerous pH levels, compared to 30 seconds with granules. 3. The granules themselves. Just a month ago there were posts explaining how it was not a clever idea to use medical grade granules, yet in this very sad accident, that is just what was used. If there is a CO2 hit before the flood, which is almost always the case, the diver cannot deal with it. Those granules were not appropriate for diving. There is widespread ignorance of what absorbers do with increasing levels of CO2 flow: many shut down giving huge CO2 spikes. Divers are doing these changes without the faintest idea of what it is they are actually doing. Training organisations have a role to explain this to their students: i.e. do NOT mess with granules other than those the unit has been designed for and tested with. I had a complete flood and caustic cocktail on a rebreather 6 years ago due to a design fault on the equipment (that is still there on units sold today). The accident was enough for me to take a lot of interest in Micropore's products. The CO2 hit that goes with a flood makes one far less able to reason about a caustic cocktail. I thought it was caustic coming into my nose, but that was an hallucination under the CO2 hit - my nose was in a half mask. Fortunately I was very close to the surface, I did bail out - albeit much too slowly, and the boat came fast. If I had been deeper, I would have been gone. As regards low risk not needing the investment: caustic cocktails are not low risk, not are they infrequent. The problem is caused by incompetent safety design IMHO. Simon's post shows the critical nature of these failures, as do the accident lists, and posts such as yours, Rons and others, show it is not uncommon. I cannot see how on earth any manufacturer can defend not dealing with these issues. Perhaps manufacturers on the forum could enlighten us? Alex Hi Alex Well first, there are several grades- and at least one manufacture is going to come out with it as an option in the near future Second the Borus has it now and one of my friends is diving it Third I already stated it would increase wOB- but that can be a minimum and for the safety well worth the effort And Wow what you base your assumption on that the CIS Canister will not stand up to the abuse of sport divers I have two cis canisters I have dived in the Meg since owning the meg other than pre production that threaded into canister- they have traveled around the world bent beat up by me- I do not baby equipment at al they work perfect I think a coupe of other people on this list are using them- a couple of my students have and are using them- So I think you are way off base- unfortunately they only work in the CIS and Meg or I would use them in everything. I do not think there is anything a sport diver could do to a canister I nor Joe nor Bill nor Rich nor any number of other peoiple have not and they still work- you do not know much about the historu of the cis canister and have some assumptions that are incorrect as to their durability. and over all toughness I would lie to know more about the risk of the mebranes- the design to keep wOB down is important but what other risk do you refer to- And where does one get an EAC and electronic warning- I would chalenge your there was a co2 hit then the flood and caustic- most of the times i have seen caustic they were not preceeded by co2 issues - and the ones I have had mellow by comparision to some- happened quickly and I discoverd why but that did not keep them from happening. A bad cO2 hit will put you top sleep or render you unable torewact- in the cases of caustic I have seen this is not the case. I think ALL training agencies emphasize use only sorb approved for the unit. People I know who got hits were using sorb or cartridges designed for the unit. Yes, he was using med grade- but caustic is caustic and why not do something to avoid it- instead of finding a reason not to avoid it. We completely agree that caustic is not a low rish although often it is perceived to be- Hope the manufactures including micropore will get interested . And in closing pads can be designed to keep aminimum of WOB- and the cis is an excellent rugged design Most units try to use water traps and that does a reasobable job but would be more efficient with a membrane to keep water out of the canister At least you and others are interested and pushing to get a solution tell me more about the electronic warnings
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18th May 2007, 20:18	#32 (permalink)
AD_ward9 So much more to learn Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Jun 2005 Location: Scotland Posts: 1,856	Re: caustic cocktail Hi Tom, The electronic warnings we use are based on the differential pressure across the scrubber. It rises 3 to 4 fold in the case of granular scrubbers and more than 10 fold in the case of EACs when there is a flood, after compensating for gas and depth. Methods that simply measure the resistance between two isolated parts can also work: the condensation is relatively high resistance compared to a cocktail. My point was that manufacturers can address this issue if the will is there. On the hydrophobic membranes, they are torn easily and in a general sports diving environment users would replace them with the wrong thing. On regular use, the pores get blocked. The materials are generally designed as surface filters, so they collect microscopic detritus. There are more than a dozen different hydrophobic membranes so I asked which material you had in mind so I could be specific. If we take as an example two materials which are quite similar, Zitex A105 and the GE Nylon equivalent, these have a high breathing resistance. The problem is to block water, but they resist gas. A 2lb/inch pressure in resisting water translates to tens of millibar in blocking gas. Moreover, when the membrane is wet, the resistance to gas increases dramatically. Some other membranes use PTFE, which introduces risk of off-gasing toxic products into the breathing loop. I agree the Stone canisters are particularly well designed, but in my view it is better to cure the problem at source. On the CO2 hit, I was not referring to one that is so bad as to knock a diver out, but one that causes the diver to get confused or even hallucinate. When measuring scrubbers in the lab, when scrubbers are wet, they both increase breathing resistance and allow CO2 to spike. It was also my experience with a heavy flood: one is not conscious of one's judgement being affected but the hallucination is proof that it is severely. Cheers, Alex Last edited by AD_ward9 : 18th May 2007 at 20:41.
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19th May 2007, 11:02	#33 (permalink)
Tom Mount New Member Current Rebreather/s: Inspiration Classic Evolution Megalodon Sport Kiss Classic Kiss Optima Other CCR Other Rebreather/s: Other CCR Join Date: Jul 2005 Location: USA Posts: 96	Re: caustic cocktail Hi Alex In all hypercapnia -hypoxia and hyperoxia the first real thing is confussion- So agree that with hypercapnia confussion comes first Where I disagree is that not all floods cause hypercapnia as some happen fast- Most I have seen or experienced were very fast A slow flood as on a dive would produce hypercapnia first and of course, it would all be down hill at that point. In addition, most often one who has a CO2 hit has limited time to respond if they even become aware of the hit. In your case it does sound as if you had a co2 hit c\with the flood- I imagine this was not the more or less explosive type caustic's I have seen. The electronic warnings sounds like a great and relatively inexpensive way to go- and maybe in the long run the safest. I would definitely use such a system. I do hope someone does produce either a safe hydrophobic membrane or the EEC On the Cis canister yes it will clog thus one must (not should but must) rinse/clean it every 30 to 50 hours. As you know the Cis looks very much like a raycor fuel filter in a diesel engine-I often wonder if it is the same material. Selection of a hydrophobiac material that provides low breathing resistance, is efficient and does not give off toxic gas (I did not know about the toxic gas issue before) would be a challenge for the manufactures. So question how does one go about installing an electronic warning system into their individual rebreathers? I for one would like to have it on all unts if your testing reflects it is dependable and can be done eaisly Most any unit can be flooded When I fist got my Evolution a few years back it flooded the first 4 dives I did quickly- It would hold pos and neg overnight- I checked the mouthpeice it on the outside was good. As this is a source that has caused floods before by having small tears in them- not so in this case at least outwardly But when I took the mouthpeice off- and looked on the inside that seals to the DSV it had a small gorove in it- so most likely a mold imperfection. Changed mouth pieces and it has not had an issue since that time- Also as these were fast (relatively ) floods I actually went upside down (did not inhale) and cleared the unit totally just as we do on the Cis and each time dived- The sorb in these cases when changed post dive were slightly damp not wet - and no taste and of course no caustic. In fact I was delighted as on the old inspiration I had never been able to get water out of it -that had gooten into the canister housing - and on the evolution it is apeice of cake- but doing a clear of this nature does run a risk of caustic thus I do not teach it ( although of course we do/did on the Cis and until veryrecently I did on the Meg and on the Optima, but trick is it has tobe done at fist flood (notice of excessing breathing resostance -not after hearing "heavy" gurgling for a prolonged period of time- just teach clearing water out of CL or in some units water traps. I use the term "heavy" gurgling to reflect 3h difference in the gurgle in the exhalation hose that people get comfortable with and then do not notice the change in sound or type gurgle thus go on to flood the unit in some cases. Anyway would love to explore the electronic warning systems - I fyou need test subjects in the field I for one would be a test subject) Was just looking at Chris' Haveranero- it is about as flood proof as anything can be -the canister is bascially sealed in such a nmanner that unless water is emitted through the inhalation hose it cannot get to the canister- he even demonstrates taking a hose and running into the exhalation side and the water simply runs out-Very impressive- (it is a passive sCR) So that may be another solution to prevention of floods of the canister Thanks for the info
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19th May 2007, 15:06	#34 (permalink)
AD_ward9 So much more to learn Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Jun 2005 Location: Scotland Posts: 1,856	Re: caustic cocktail Quote: (Originally Posted by Tom Mount) Was just looking at Chris' Haveranero- it is about as flood proof as anything can be -the canister is bascially sealed in such a nmanner that unless water is emitted through the inhalation hose it cannot get to the canister- he even demonstrates taking a hose and running into the exhalation side and the water simply runs out-Very impressive- (it is a passive sCR) So that may be another solution to prevention of floods of the canister Hi Tom, Your post was full of little gems. We will publish in full the flood monitoring details (the circuit is already published on the DL site). I will call to follow up with you on the testing at a suitable time. On materials, if one is going down the hydrophobic membrane route, then PVDF (Kynar) membranes appear to be the safest. Kynar is a material we like for rebreather parts generally, as it is the purest synthetic resin available and is mouldable without softeners and plasticisers, as well as being very tough. The problem is primarily one of ensuring the users clean the membrane regularly or replace it, and ensuring the user cannot replace the membrane with something else such as by welding the membrane to a ring so they have to buy the ring and membrane as an assembly. These membranes are fragile in the micron thicknesses of hydrophobic membrane, but it is obvious when it is torn. Your comment about Chri's Haveranero in particular has piqued my interest. Is there anywhere one can find more information? Cheers, Alex Last edited by AD_ward9 : 19th May 2007 at 15:46.
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19th May 2007, 15:09	#35 (permalink)
Tom Mount New Member Current Rebreather/s: Inspiration Classic Evolution Megalodon Sport Kiss Classic Kiss Optima Other CCR Other Rebreather/s: Other CCR Join Date: Jul 2005 Location: USA Posts: 96	Re: caustic cocktail For those not up on PH etc- you may like the following material and the info on the web page How You Rot & Rust How You Rot & Rust It all begins with pH. THE pH REGULATORY SYSTEM OF THE BODY The pH balance of the human bloodstream is recognized by all medical physiology texts as one of the most important biochemical balances in all of human body chemistry. pH is the acronym for "Potential Hydrogen". In definition, it is the degree of concentration of hydrogen ions in a substance or solution. It is measured on a logarithmic scale from 0 to 14. Higher numbers means a substance is more alkaline in nature and there is a greater potential for absorbing more hydrogen ions. Lower numbers indicate more acidity with less potential for absorbing hydrogen ions. Our body pH is very important because pH controls the speed of our body's biochemical reactions. It does this by controlling the speed of enzyme activity as well as the speed that electricity moves through our body. The higher (more alkaline) the pH of a substance or solution, the more electrical resistance that substance or solution holds. Therefore, electricity travels slower with higher pH. All biochemical reactions and electrical (life) energy are under pH control. If we say something has an acid pH, we are saying it is hot and fast. As an example, look at the battery of your car. It's an acid battery. On cold days you want it to be hot and ready, and you want your car to start fast. Alkaline pHon the other hand, biochemically speaking, is slow and cool. Compare it to an alkaline battery in a flashlight. You want that battery to be cool, and to burn out slowly. Here is an example of how pH can control. Look around you at society in general. Do you see people getting exhausted, burned out, and quick to anger? Do you see a rise in violence? In part it could be due to the fact that people today lean to an acid pH. As a society we are running hot and fast. How did we get there? We guzzle coffee for breakfast (acid), burgers for lunch (acid), wash it down with king size colas (acid), and have a pizza (acid) for dinner. In fact, with this scenario, you could easily correlate the rise of violence in our society with the increasing number of fast food restaurants on every corner. But I digress. However, this does lead me to the second part of the pH and digestive metabolic equation. pH is under the direct control of what we put into our mouths. Kind of makes sense doesn't it? What we eat and drink will impact where our body's pH level falls, and our body's pH will control the activity of every metabolic function happening in our body. pH is behind the body's electrical system and intracellular activity as well as the way our bodies utilize enzymes, minerals, and vitamins. That is why pH is one of the first things to be looked at if you are experiencing unbalance in your body in any way, shape, or form. And since our body's pH level is a direct result of what we eat and drink, anytime we are experiencing imbalance, we need to look at what we have historically been eating and drinking because this impacts our pH. It's a circle. You can't look at one without looking at the other. What we eat and drink is directly tied to the functioning of our digestive system. From our mouth through our small intestines and through our colon, that system plays the most important part in our physical well being. This system, what we feed it, and how it impacts our pH, is the essential core that determines whether we have perfect health or not. It is really so simple. Now you may be thinking that all of this makes perfect sense. It is so simple that you would think that modern medicine could look at it, put two and two together and simply attempt to bring people back into balance through the food that they eat. Hippocrates said, "Let food be your medicine. Let medicine be your food." If it were only so simple. Modern medicine has gotten to where it is today in part through a scientific and philosophical debate that culminated in the 19th century. On one side of the debate was French microbiologist Antoine Bechamp. On the other side was French microbiologist Louis Pasteur. Bechamp and Pasteur strongly disagreed in their bacteriological theories. They argued heatedly about who was correct. It was... The Argument that Changed the Course of Medicine. Pasteur promoted a theory of disease that described non-changeable microbes as the primary cause of disease. This is the theory of monomorphism. This theory says that a microorganism is static and unchangeable. It is what it is. Disease is solely caused by microbes or bacteria that invade the body from the outside. (This is the germ theory.) Bechamp held the view that microorganisms can go through different stages of development and they can evolve into various growth forms within their life cycle. This is the theory of pleomorphism. He observed microbe like particles in the blood which he called microzymas. These microbes would change shape as individuals became diseased, and for Bechamp, this was the cause of disease; hence disease comes from inside the body. Another scientist of the day, Claude Bernard, entered into the argument and said that it was actually the "milieu" or the environment that is all important to the disease process. Microbes do change and evolve, but how they do so is a result of the environment (or terrain) to which they are exposed. Hence, for Bechamp, microbes, being pleomorphic, will change according to the environment to which they are exposed. Therefore, disease in the body, as a biological process, will develop and manifest dependent upon the state of the internal biological terrain. At the core of that terrain, is pH. Both men acknowledged certain aspects of each other's research, but it Pasteur was the stronger, more flamboyant, and more vocal opponent when compared to the quiet Bechamp. Pasteur also came from wealth and had the right family connections. He went to great lengths to disprove Bechamp's view. Pasteur eventually managed to convince the scientific community that his view alone was correct. Bechamp felt that this diverted science down a deplorable road - a road that held only half the truth. On his deathbed, Pasteur finally acknowledged Bechamp's work and said, "Bernard was correct: the microbe is nothing: the terrain is everything." It was a 180 degree turnaround. With his death imminently at hand, he as much as admitted that his germ theory had flaws. But his admission fell on deaf ears. It was far too late. It could not reverse the inertia of ideas that had already been accepted by mainstream science at that time. Allopathic (drug based) medicine was firmly entrenched on the road that was paved by Pasteur. The result of that road is what you see today practiced as medicine. When a body is out of balance, doctors attempt to put it back into balance, first through drugs, then through surgery. The general effect is to remove the symptoms, not to deal with the ultimate cause of the ailment. Please I have no intention of offending MD's this is just the material on the web page- even though as an ND I do agree in the treatment of cause rather than symptom- but all approaches have merit and time and place, I even recently had surgery due to it being a correct time and place- of course aftert two months replaced the meds with natural substances free of side effects- but this was a good page and has several other "chapters" on PH without getting into allot of biochemistry so all can understand and benefit from it. Last edited by Tom Mount : 19th May 2007 at 15:20.
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19th May 2007, 15:25	#36 (permalink)
Tom Mount New Member Current Rebreather/s: Inspiration Classic Evolution Megalodon Sport Kiss Classic Kiss Optima Other CCR Other Rebreather/s: Other CCR Join Date: Jul 2005 Location: USA Posts: 96	Re: caustic cocktail Quote: (Originally Posted by AD_ward9) Hi Tom, Your post was full of little gems. We will publish in full the flood monitoring details (the circuit is already published on the DL site). I will call to follow up with you on the testing at a suitable time. Your comment about Chri's Haveranero in particular has piqued my interest. Is there anywhere one can find more information? Cheers, Alex Alex could you contact me at tom.mount@Chi-EnergyDynamics.com You have my full attention with the electronic warning- althouh i still like the idea of a safe membrane so unit can be cleared and stayed on UM!- for me both sound good combined warning- abilty to prevent - and then use the techniques to clear all water from the system- What the heck if you are gonna ask for something ask BIG
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19th May 2007, 19:55	#37 (permalink)
Genesis Bubbless Box of Death Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: Oct 2005 Location: Sunny Florida Posts: 1,396	Re: caustic cocktail There are two methods I can think of with regards to electronic warning. The first is as Alex outlined - trigger on WOB changes. However, this may or may not give warning, depending on the nature of the flood (a swimmer in a horizontal position could potentially flood a good bit of an EAC cannister without impairing gas flow enough to trip the sensor, and if it sits in there long enough it'll stil nail you.) The second however, appears to be just as valid if not more so, at least for an OTS design which requires that the cocktail get past the "T" piece on the inhale lung before it can get YOU. And that is to monitor for liquid intrusion at the exit of the cannister (inhale side) with a probe set that will trip an alarm on the handset and/or HUD when flooded. This SHOULD give you enough warning of an impending disaster to bail, and it would work no matter how the cocktail got there. If you get liquid of a low enough conductivity on the probes the alarm goes off, and if the liquid must pass the probes to get into the inhale hose and counterlung, that should do it. I will have to run some tests on this, but this appears to be pretty simple to do, because ordinary condensation (which of course is all over the inside of the unit in operation) should have MUCH higher resistance than a cocktail, which is full of ions and thus would have extremely low resistence. Floods of the magnitude required to pass the 'sorb and emerge on the inhale side headed for your mouth would, I suspect, reliably trip a probe set. What am I missing? __________________ "A venturesome minority will always be eager to get off on their own, and no obstacles should be placed in their path; let them take risks for Godsake, let them get lost, sunburnt, stranded, drowned, eaten by bears, buried alive under avalanches - that is the right and privilege of any free American." http://www.denninger.net http://www.diversunion.org/liability.htm - Fix the Diving Cert racket
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20th May 2007, 15:27	#39 (permalink)
AD_ward9 So much more to learn Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Jun 2005 Location: Scotland Posts: 1,856	Re: caustic cocktail Quote: (Originally Posted by Genesis) I will have to run some tests on this, but this appears to be pretty simple to do, because ordinary condensation (which of course is all over the inside of the unit in operation) should have MUCH higher resistance than a cocktail, which is full of ions and thus would have extremely low resistence. Floods of the magnitude required to pass the 'sorb and emerge on the inhale side headed for your mouth would, I suspect, reliably trip a probe set. What am I missing? You are not missing anything Karl. If you measure less than 1K Ohm between two probes in the port from the head to the inhale bag then it is flooded. To see the effect of a flood, just put multimeter probes into a cup of clean water and drop in some granules. As you say, there are so many ions the resistance drops really quick. Alex
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20th May 2007, 17:36	#40 (permalink)
Outlaw In search of Law breaking Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Aug 2006 Location: Cyprus, Nicosia Posts: 640	Re: caustic cocktail hey guys, is there a chance that you have some caustic fumes due to the scruber being wet and then to continue the dive breathing from the loop? i once had an incident where i was under for about 2 hours, and suddenly i felt like throwing up, which i did. i managed to to shut the DVS valve and when on the bail out, had a five minute breathing on that, which was air, and then went back on the loop and i could still manage to finish the dive, well i had a scooter battery running out so i had a long swim. This was last year by the way. at the time i was thinking that it was due to the fact that during the dive i was increasing and decreasing my set point on 02, but when i came home, i realized that my scrubber was sort of "half wet".... i have the pictures somewhere....i'll try and find them and post. it was really strange for me, especially now that i read all these posts, but there was no clarification if a scrubber can actually get wet, and have no issues with the dive....can this thing happen, or once water touches the sofnolime then is all over. Please advice. i would like to hear your views. promise to sent the pictures which will help you realize what i mean. Chees. Spyros. __________________ CMAS - IANTD - TDI Kamikazi Instrustor Trainer DIRRebreather Team Member ---------------------------- "Once an Outlaw, always an Outlaw"
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