What cylinder characteristics are preferred

Deep Thought · 17th December 2005, 02:51

Quote: (Originally Posted by mverick)

From what is posted. The smaller 19 Worth is still heavier then the Faber 20. Then if they won't boost it to the 3400psi. You're short gas too... with a heavier tank.

-----------psi
---------+10%_ CF _Dia ___Height Weight WeightMT Weight Full
Faber 13 2400_ _13 3.9 ____14 ____5.9 _____-2.25 ___-3.31
Faber 20 2400 __20 3.9 ____19.5 __7.5 ______-1.5 ____-3
Worth 13 3130 __13 4 _____12.5 ___6.9 _____-2.3 ____-3.3
Worth 19 3130 __19 4 _____16.5 ___9.3 _____-2.2 ____-3.8
Worth 30 3130 __30 5.4 ____14.75__14.9 ____-3.9 _____-6
Worth 40 3130 __40 5.4 ____18.75 __18.1 ____-3.3 ____-6.3

One of the problems is that U.S. consumers stick to the stupid system of Cu. Ft. measurement that relates to fill pressure rather than the internal volume measurement which is a lot more sensible.

If a cylinder is measured at 2 / 3 liter it relates to the overall size of the cylinder, plus or minus some wall thickness of course….So if you choose the pressure that you are comfortable filling any gas then you decide how much gas you want to take with you.

To me size matters, and I’m proud to say “Small Is Better” big just gets in the way… “it’s short, but at least it’s skinny” is my motto.

I want the smallest cylinder (2 & 3 liter is ideal size) make it with high strength steel so you can pump it low or pump it high and put enough steel so the cylinder is slightly negative when empty.

Pressure is, and is not relevant to this poll in the U.S. market.

Take the current 13 and 19 cu. Ft faber cylinders that are on the U.S. market, with a total pressure of 2640 psi. – they are approximately 2 and 3 liters internal volume. If you could make this cylinder out of high strength steel that could withstand 3442 psi then you would have more compressed gas than 13/19 Cu. Ft.

You could also achieve this concept if you made the cylinder of thicker lower grade steel – you have to have more wall thickness to withstand the pressure. This is what they currently have with the heavy 3442 cylinders.

So the real question that I think Lead King is asking is if you want a cylinder, do you want Cheap Heavy, or would you want less weight and the same or more gas.

Go back to the internal volume 2 / 3 liter size, make it out of high strength steel with reasonable weight characteristics and pump it to whatever you feel is appropriate. If you want low pressure then you get 13 or 19 cu. Ft. if you are comfortable filling gas to higher pressure then you get more gas! So you really don’t loose anything compared to what we are currently using, and you could gain more.

Remember boats don’t burn down because of pressure, boats burn down due to how oxygen is handled low or high pressure. If you go from 0 – 2400 psi, or if you go from 0 -3442 in a split second you will have a problem.

If I wanted heavy tanks I could go back to open circuit doubles

***jradomski*** · 17th December 2005, 04:21

Quote: (Originally Posted by leadking)

I am working with Worthington to design new 2/3 liter cylinders and want to know what features are important to end users;

1. Weight is most important (neutral buoyancy 2400 psi)

2. Total gas volume ( -2 neg. 3442 psi)

3. Price (heavy but cheap)

I answered #2 only because I prefer the cylinders slightly negative.. The 3442 rating is nice but it has to have similiar dimensions as cylindersd avilable today,
a) since it may have toi fit in a case
B) alot of places do not have boosters, so you need the volume to make up forlow pressure fills.. Unless the place has a big cascade, without a booster you are looking at fills even below 1500 psi... on a 3l cylinder (based on 2400) thats not that bad.. a 2l doent leave alot of extra gas - thats one big dive..

if your going to do 3442 they have to have the same volume as the lp versions do at lower pressures..

leadking · 17th December 2005, 16:18

if your going to do 3442 they have to have the same volume as the lp versions do at lower pressures..[/quote]

3 liters is 3 liters.

One of the things that I hope most of this group understands is additional pressure equals additional gas volume. I've sold over 50,000 cylinders in the last few years and one of the most confusing issues I've run into is the absolute belief that a cylinder must be filled to its rated pressure. I am trying to fill the needs of rebreather divers, but there is no consensus. Even the rebreather manufacturers give a different view than what this poll is suggesting.

I want to supply the end customer with what they want, not what I or the manufacturers think you want.

Please say what you really need, I'm going to invest 10,000's of thousands of dollars on this project and want to know.

mverick · 17th December 2005, 16:41

Quote: (Originally Posted by Deep Thought)

One of the problems is that U.S. consumers stick to the stupid system of Cu. Ft. measurement that relates to fill pressure rather than the internal volume measurement which is a lot more sensible.

Well, I guess that is based on who you are and what your thinking is.

Telling me they have a new 3liter out. Then I have to ask a bunch of questions. Not even knowing anything other then approx size. Heck, it could be a 1000psi tank. Although I doubt it. I like knowing capacity.

Telling me there is a new 40cf out. I know, it holds the amount of gas I'm looking to put on my rig. And still ask a bunch of questions.

That 3 liter has a lot of questions to be asked too. Like height, diameter, pressure, weight, bouyancy. True that telling me it's a 3liter. I know approx size. But I don't want to put 20lbs extra on my rig. To me, I wanna know all the answers. So although knowing it is a 3l is nice. I'm more into what is the size of the tank.

I love the size of the Worth40's. It's just the weight that kills it for me.

Got away from duals for a bad back. Not wanting to add any extra weight.

***jradomski*** · 19th December 2005, 02:31

Quote: (Originally Posted by leadking)

if your going to do 3442 they have to have the same volume as the lp versions do at lower pressures..

3 liters is 3 liters.

One of the things that I hope most of this group understands is additional pressure equals additional gas volume. I've sold over 50,000 cylinders in the last few years and one of the most confusing issues I've run into is the absolute belief that a cylinder must be filled to its rated pressure. I am trying to fill the needs of rebreather divers, but there is no consensus. Even the rebreather manufacturers give a different view than what this poll is suggesting.

I want to supply the end customer with what they want, not what I or the manufacturers think you want.

Please say what you really need, I'm going to invest 10,000's of thousands of dollars on this project and want to know.[/quote]

well the 19 is surely less than 3l, so if I cant get a full fill I have less gas.... the 30 might be close but its too fat and heavy for most of the rebreathers out there.. give me a 3l tank with the same (or very close) to a faber 3l (20), and you have a winner..

They do 232bar 3l tanks in the UK that are the same size as the US 2400psi 3l tanks..

leadking · 21st December 2005, 22:07

A 3 liter tank is 183 cu. inches at 3442 psi, it is almost 25 CF/at 2400 psi it is 17cf. If I make a lightweight 2400 it will not be plus rated so 2400 psi is it. A 3 liter tank at 2400+ will be 19 cf.

Our 2/3 liter cylinders will be the same configuration as Faber's

Lee
www.seapearls.com

***jradomski*** · 21st December 2005, 22:43

Quote: (Originally Posted by leadking)

A 3 liter tank is 183 cu. inches at 3442 psi, it is almost 25 CF/at 2400 psi it is 17cf. If I make a lightweight 2400 it will not be plus rated so 2400 psi is it. A 3 liter tank at 2400+ will be 19 cf.

Our 2/3 liter cylinders will be the same configuration as Faber's

Lee
www.seapearls.com

depends on what gas you put in it..

You get more oxygen in the same cylinder than you do "air".. and you get more "air" than you do with a cylinder with a He mix..

Plus you also have to take temperature into accound..

You cant go quoting gas capacity without qualifying what gas it is and what temperature you are specifying it at..

silent running · 22nd December 2005, 06:33

Quote: (Originally Posted by jradomski)

depends on what gas you put in it..

You get more oxygen in the same cylinder than you do "air".. and you get more "air" than you do with a cylinder with a He mix..

Plus you also have to take temperature into accound..

You cant go quoting gas capacity without qualifying what gas it is and what temperature you are specifying it at..

Hi Joe, very interesting. Had not thought about differing gas densities as they relate to cylinder capacities. I learn something new everyday... -Andy

mikedive · 23rd December 2005, 00:25

Hi Leadking,

I tried many tanks sizes at my O2ptima and I personally use Al 13cf @ 3000 psi in fresh water and I'm using the Ouroboros steel tanks, 2l HP from Kevin in salt water.
The problem for me is very easy to decide what is better to produce because weight you can add if you need in many ways like steel back plates and weight pieces in different places to balance the unit like you want but if the tanks are to heavy you have no way to lower the weight of the unit!!!!
This is my personal point of view in especial if you need fly with your tanks.

Cheers,

Mike - www.protecdiving.com

***jradomski*** · 23rd December 2005, 00:51

Quote: (Originally Posted by silent running)

Hi Joe, very interesting. Had not thought about differing gas densities as they relate to cylinder capacities. I learn something new everyday... -Andy

Its not gas densities. its the compressibility of the gases and the temperature determineshow much energy the molecules have, colder temps allow more gas at same temperature.. oxygen is very compressible, helium isn't

View Poll Results: CYLINDER PREFERENCES
light -neutrally buoyant 2400 psi	7	22.58%
medium-max gas, 3442 psi, couple of lbs. neg	21	67.74%
heavy- costs the least but wall thickness reduces gas 4 lbs neg	3	9.68%
Voters: 31. You may not vote on this poll

17th December 2005, 02:51	#11 (permalink)
Deep Thought Custom Title Allowed! Current Rebreather/s: Inspiration Vision Classic Kiss Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Megalodon Sport Kiss Classic Kiss Optima Join Date: Apr 2005 Location: Great Lakes Posts: 190	Re: What cylinder characteristics are preferred Quote: (Originally Posted by mverick) From what is posted. The smaller 19 Worth is still heavier then the Faber 20. Then if they won't boost it to the 3400psi. You're short gas too... with a heavier tank. -----------psi ---------+10%_ CF _Dia ___Height Weight WeightMT Weight Full Faber 13 2400_ _13 3.9 ____14 ____5.9 _____-2.25 ___-3.31 Faber 20 2400 __20 3.9 ____19.5 __7.5 ______-1.5 ____-3 Worth 13 3130 __13 4 _____12.5 ___6.9 _____-2.3 ____-3.3 Worth 19 3130 __19 4 _____16.5 ___9.3 _____-2.2 ____-3.8 Worth 30 3130 __30 5.4 ____14.75__14.9 ____-3.9 _____-6 Worth 40 3130 __40 5.4 ____18.75 __18.1 ____-3.3 ____-6.3 One of the problems is that U.S. consumers stick to the stupid system of Cu. Ft. measurement that relates to fill pressure rather than the internal volume measurement which is a lot more sensible. If a cylinder is measured at 2 / 3 liter it relates to the overall size of the cylinder, plus or minus some wall thickness of course….So if you choose the pressure that you are comfortable filling any gas then you decide how much gas you want to take with you. To me size matters, and I’m proud to say “Small Is Better” big just gets in the way… “it’s short, but at least it’s skinny” is my motto. I want the smallest cylinder (2 & 3 liter is ideal size) make it with high strength steel so you can pump it low or pump it high and put enough steel so the cylinder is slightly negative when empty. Pressure is, and is not relevant to this poll in the U.S. market. Take the current 13 and 19 cu. Ft faber cylinders that are on the U.S. market, with a total pressure of 2640 psi. – they are approximately 2 and 3 liters internal volume. If you could make this cylinder out of high strength steel that could withstand 3442 psi then you would have more compressed gas than 13/19 Cu. Ft. You could also achieve this concept if you made the cylinder of thicker lower grade steel – you have to have more wall thickness to withstand the pressure. This is what they currently have with the heavy 3442 cylinders. So the real question that I think Lead King is asking is if you want a cylinder, do you want Cheap Heavy, or would you want less weight and the same or more gas. Go back to the internal volume 2 / 3 liter size, make it out of high strength steel with reasonable weight characteristics and pump it to whatever you feel is appropriate. If you want low pressure then you get 13 or 19 cu. Ft. if you are comfortable filling gas to higher pressure then you get more gas! So you really don’t loose anything compared to what we are currently using, and you could gain more. Remember boats don’t burn down because of pressure, boats burn down due to how oxygen is handled low or high pressure. If you go from 0 – 2400 psi, or if you go from 0 -3442 in a split second you will have a problem. If I wanted heavy tanks I could go back to open circuit doubles __________________ Creature Of Habits; Mostly Bad www.gudcscuba.com
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17th December 2005, 04:21	#12 (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: 2,887	Re: What cylinder characteristics are preferred Quote: (Originally Posted by leadking) I am working with Worthington to design new 2/3 liter cylinders and want to know what features are important to end users; 1. Weight is most important (neutral buoyancy 2400 psi) 2. Total gas volume ( -2 neg. 3442 psi) 3. Price (heavy but cheap) I answered #2 only because I prefer the cylinders slightly negative.. The 3442 rating is nice but it has to have similiar dimensions as cylindersd avilable today, a) since it may have toi fit in a case B) alot of places do not have boosters, so you need the volume to make up forlow pressure fills.. Unless the place has a big cascade, without a booster you are looking at fills even below 1500 psi... on a 3l cylinder (based on 2400) thats not that bad.. a 2l doent leave alot of extra gas - thats one big dive.. if your going to do 3442 they have to have the same volume as the lp versions do at lower pressures.. __________________ 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.
(Online)

17th December 2005, 16:18	#13 (permalink)
leadking New Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Nov 2005 Location: Minneapolis Posts: 56	Re: What cylinder characteristics are preferred if your going to do 3442 they have to have the same volume as the lp versions do at lower pressures..[/quote] 3 liters is 3 liters. One of the things that I hope most of this group understands is additional pressure equals additional gas volume. I've sold over 50,000 cylinders in the last few years and one of the most confusing issues I've run into is the absolute belief that a cylinder must be filled to its rated pressure. I am trying to fill the needs of rebreather divers, but there is no consensus. Even the rebreather manufacturers give a different view than what this poll is suggesting. I want to supply the end customer with what they want, not what I or the manufacturers think you want. Please say what you really need, I'm going to invest 10,000's of thousands of dollars on this project and want to know. Last edited by leadking : 17th December 2005 at 16:20.
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17th December 2005, 16:41	#14 (permalink)
mverick ScubaPimp Current Rebreather/s: Megalodon Other CCR Home Build Other Rebreather/s: Other CCR Home Build Join Date: Aug 2005 Posts: 510	Re: What cylinder characteristics are preferred Quote: (Originally Posted by Deep Thought) One of the problems is that U.S. consumers stick to the stupid system of Cu. Ft. measurement that relates to fill pressure rather than the internal volume measurement which is a lot more sensible. Well, I guess that is based on who you are and what your thinking is. Telling me they have a new 3liter out. Then I have to ask a bunch of questions. Not even knowing anything other then approx size. Heck, it could be a 1000psi tank. Although I doubt it. I like knowing capacity. Telling me there is a new 40cf out. I know, it holds the amount of gas I'm looking to put on my rig. And still ask a bunch of questions. That 3 liter has a lot of questions to be asked too. Like height, diameter, pressure, weight, bouyancy. True that telling me it's a 3liter. I know approx size. But I don't want to put 20lbs extra on my rig. To me, I wanna know all the answers. So although knowing it is a 3l is nice. I'm more into what is the size of the tank. I love the size of the Worth40's. It's just the weight that kills it for me. Got away from duals for a bad back. Not wanting to add any extra weight.
(Online)

19th December 2005, 02:31	#15 (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: 2,887	Re: What cylinder characteristics are preferred Quote: (Originally Posted by leadking) if your going to do 3442 they have to have the same volume as the lp versions do at lower pressures.. 3 liters is 3 liters. One of the things that I hope most of this group understands is additional pressure equals additional gas volume. I've sold over 50,000 cylinders in the last few years and one of the most confusing issues I've run into is the absolute belief that a cylinder must be filled to its rated pressure. I am trying to fill the needs of rebreather divers, but there is no consensus. Even the rebreather manufacturers give a different view than what this poll is suggesting. I want to supply the end customer with what they want, not what I or the manufacturers think you want. Please say what you really need, I'm going to invest 10,000's of thousands of dollars on this project and want to know.[/quote] well the 19 is surely less than 3l, so if I cant get a full fill I have less gas.... the 30 might be close but its too fat and heavy for most of the rebreathers out there.. give me a 3l tank with the same (or very close) to a faber 3l (20), and you have a winner.. They do 232bar 3l tanks in the UK that are the same size as the US 2400psi 3l tanks.. __________________ 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.
(Online)

21st December 2005, 22:07	#16 (permalink)
leadking New Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Nov 2005 Location: Minneapolis Posts: 56	Re: What cylinder characteristics are preferred A 3 liter tank is 183 cu. inches at 3442 psi, it is almost 25 CF/at 2400 psi it is 17cf. If I make a lightweight 2400 it will not be plus rated so 2400 psi is it. A 3 liter tank at 2400+ will be 19 cf. Our 2/3 liter cylinders will be the same configuration as Faber's Lee www.seapearls.com
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21st December 2005, 22:43	#17 (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: 2,887	Re: What cylinder characteristics are preferred Quote: (Originally Posted by leadking) A 3 liter tank is 183 cu. inches at 3442 psi, it is almost 25 CF/at 2400 psi it is 17cf. If I make a lightweight 2400 it will not be plus rated so 2400 psi is it. A 3 liter tank at 2400+ will be 19 cf. Our 2/3 liter cylinders will be the same configuration as Faber's Lee www.seapearls.com depends on what gas you put in it.. You get more oxygen in the same cylinder than you do "air".. and you get more "air" than you do with a cylinder with a He mix.. Plus you also have to take temperature into accound.. You cant go quoting gas capacity without qualifying what gas it is and what temperature you are specifying it at.. __________________ 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.
(Online)

22nd December 2005, 06:33	#18 (permalink)
silent running Mature mouth breather Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Jun 2005 Location: U.S.A. Brooklyn, New York Posts: 1,813	Re: What cylinder characteristics are preferred Quote: (Originally Posted by jradomski) depends on what gas you put in it.. You get more oxygen in the same cylinder than you do "air".. and you get more "air" than you do with a cylinder with a He mix.. Plus you also have to take temperature into accound.. You cant go quoting gas capacity without qualifying what gas it is and what temperature you are specifying it at.. Hi Joe, very interesting. Had not thought about differing gas densities as they relate to cylinder capacities. I learn something new everyday... -Andy
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23rd December 2005, 00:25	#19 (permalink)
mikedive Custom Title Allowed! Current Rebreather/s: Megalodon Other CCR Other Rebreather/s: Inspiration Classic Optima Other CCR Join Date: Apr 2005 Location: South Brazil, Texas and Mexico Posts: 327	Re: What cylinder characteristics are preferred Hi Leadking, I tried many tanks sizes at my O2ptima and I personally use Al 13cf @ 3000 psi in fresh water and I'm using the Ouroboros steel tanks, 2l HP from Kevin in salt water. The problem for me is very easy to decide what is better to produce because weight you can add if you need in many ways like steel back plates and weight pieces in different places to balance the unit like you want but if the tanks are to heavy you have no way to lower the weight of the unit!!!! This is my personal point of view in especial if you need fly with your tanks. Cheers, Mike - www.protecdiving.com
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23rd December 2005, 00:51	#20 (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: 2,887	Re: What cylinder characteristics are preferred Quote: (Originally Posted by silent running) Hi Joe, very interesting. Had not thought about differing gas densities as they relate to cylinder capacities. I learn something new everyday... -Andy Its not gas densities. its the compressibility of the gases and the temperature determineshow much energy the molecules have, colder temps allow more gas at same temperature.. oxygen is very compressible, helium isn't __________________ 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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