Dual Pony Tanks?

**Freef** · 13th November 2007, 16:50

The lift industry uses a check valve that works at with pressures of 20 bar [hydraulic oil though], so I imagine there may be a small enough device.

But-the way they work is on a sudden pressure differential, so turning on one tank and then the other could cause problems. Anyway, isn't losing half your gas defeating the object of the two ponies?

Or are you looking at two regs?

firemandiver · 14th November 2007, 03:14

I suppose you're right about losing half the gas and defeating the whole purpose, but the likelyhood of a hose burst is pretty remote. I've have used my various OC setups( 3 guage console and air integrated hosed computers ) for years and never had a hose bust. I've had an O ring leak a little around the fitting, but never a total hose failure. I just want the check valve or manual shutoff just in case. If the HP crossover hose were to fail, I could still isolate the main tank and bail out safely. I'm also starting to think about plumbing the crossover with a length of ridgid 1/4 stainless line and swagloc fittings, as Stumpy suggested, instead of a flexible HP hose. The hard line connection between the two tanks would add some extra stability. It would be almost bulletproof if I end up going that route. I could go with two regs, but I really like the idea of only one 1st stage. It is simple, neat, and effective. Thanks again for all the input on my project. Luckily I'm not in a tremendous rush to get this done, so I have the time to ponder the pros and cons of the different theroies on how to do this. As always, I'm very grateful for all the help. FD.

**Freef** · 14th November 2007, 16:19

Why not get a long enough twinset manifold and then an isolator on one side, possibly with a slob knob, if you are going that way.

Oh, I think you call twinsets 'doubles' in the US-two tanks that have a HP link.

lof · 15th November 2007, 04:18

or isolators on both sides?
Golem Gear, Inc. - LOLA Universal DIN Valve

firemandiver · 15th November 2007, 17:38

I had originally thought about trying to use a "doubles" manifold, but there are a few inherent problems with that idea. 1) The Dolphin is 18 or so inches wide, so the isolator/tie bar would have to be custom made if that's even possible. 2) The tie bar/valve assy would certainly interfere with the connection of the hoses, Oxy2, and OPV. I do like the LOLA valve, though. Perhaps I could devise a crossover using that on the main tank and a standard din valve on tank 2. Plumb the crossover with 1/4 ss line and bend/route it so it does not interfere with the hoses and such. That may be a possibility. I'll contact Golem and pick their brains a little. Thanks, FD.

**Freef** · 15th November 2007, 19:41

There wouldn't be a problem with a long bar, especially with an offset isolator, it's just a bit of turned stailless with the right threads and 'O' rings, a competent engineering company could knock one up for you.

The downside is the length, and the risk of damage to the manifold if it gets knocked.

jaap · 21st November 2007, 15:10

Quote: (Originally Posted by firemandiver)

I had originally thought about trying to use a "doubles" manifold, but there are a few inherent problems with that idea. 1) The Dolphin is 18 or so inches wide, so the isolator/tie bar would have to be custom made if that's even possible. 2) The tie bar/valve assy would certainly interfere with the connection of the hoses, Oxy2, and OPV. I do like the LOLA valve, though. Perhaps I could devise a crossover using that on the main tank and a standard din valve on tank 2. Plumb the crossover with 1/4 ss line and bend/route it so it does not interfere with the hoses and such. That may be a possibility. I'll contact Golem and pick their brains a little. Thanks, FD.

You could use valves with dual exits, like H-valves or better the LOLA or Aircon dual valves. Then simply get a transfill whip of approx apropriate lenght w/o gauge. Connect the cylinders and you have a flexible manifold system with two isolators. As a bonus you can separate filled tanks for transport and get a fill whip.

If you go for that just make sure you get a whip with a reliable bleeder valve given it will be important that it does not leak.

Something like this whip:
http://www.oceanictech.se/images/pro...aver-10895.jpg

4ster · 22nd November 2007, 00:52

This is a different approach to what you are trying to do.

Don't connect them. Instead run the first stage on your left shoulder to one of the combo BC inflator/regulator things. On your right shoulder run a standard octopus. Simpler than connecting them together and it eliminates a potential failure point.

Just a thought.

firemandiver · 22nd November 2007, 01:40

Thought about that as well. Already using an Air2. Was just trying to eliminate the 2nd complete system. In no hurry to do this, just looking at all angles. Thanks, FD

fltekdiver · 21st December 2007, 03:17

I heard somone say you can flip the two tanks upside down, and being I'm a photographer, I really dont want to sling my bail out. I'm currentley using a 13cf tank on my left side for B/C and dry suit inflation, a 13cf tank on my right side, slinging under my right arm, strickley for bail out, for 60' or less FSW, and I use a 19cf for 100' or less, and a 27cf tank on the lower rear for breathing gas.

I would love to mount both 13's on the side of my shell upside down, and have the 27cf as breathing gas ony.

This is a great thread, I'm to stuck in the same situation.

13th November 2007, 16:50	#21 (permalink)
Freef Custom Title Disallowed! Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Jan 2006 Location: Land of the Freef, UK. Posts: 1,356	Re: Dual Pony Tanks? The lift industry uses a check valve that works at with pressures of 20 bar [hydraulic oil though], so I imagine there may be a small enough device. But-the way they work is on a sudden pressure differential, so turning on one tank and then the other could cause problems. Anyway, isn't losing half your gas defeating the object of the two ponies? Or are you looking at two regs? __________________ David. Currently owner of two differently sized ankles.
(Offline)

14th November 2007, 03:14	#22 (permalink)
firemandiver Let's Go Diving! Current Rebreather/s: Dolphin Home Build Other Rebreather/s: Dolphin Home Build Join Date: Sep 2007 Location: gulfport, ms Posts: 165	Re: Dual Pony Tanks? I suppose you're right about losing half the gas and defeating the whole purpose, but the likelyhood of a hose burst is pretty remote. I've have used my various OC setups( 3 guage console and air integrated hosed computers ) for years and never had a hose bust. I've had an O ring leak a little around the fitting, but never a total hose failure. I just want the check valve or manual shutoff just in case. If the HP crossover hose were to fail, I could still isolate the main tank and bail out safely. I'm also starting to think about plumbing the crossover with a length of ridgid 1/4 stainless line and swagloc fittings, as Stumpy suggested, instead of a flexible HP hose. The hard line connection between the two tanks would add some extra stability. It would be almost bulletproof if I end up going that route. I could go with two regs, but I really like the idea of only one 1st stage. It is simple, neat, and effective. Thanks again for all the input on my project. Luckily I'm not in a tremendous rush to get this done, so I have the time to ponder the pros and cons of the different theroies on how to do this. As always, I'm very grateful for all the help. FD.
(Online)

14th November 2007, 16:19	#23 (permalink)
Freef Custom Title Disallowed! Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Jan 2006 Location: Land of the Freef, UK. Posts: 1,356	Re: Dual Pony Tanks? Why not get a long enough twinset manifold and then an isolator on one side, possibly with a slob knob, if you are going that way. Oh, I think you call twinsets 'doubles' in the US-two tanks that have a HP link. __________________ David. Currently owner of two differently sized ankles.
(Offline)

15th November 2007, 04:18	#24 (permalink)
lof RebreatherWorld Sponsor Current Rebreather/s: Megalodon Prism Topaz Sport Kiss Classic Kiss MK 15.X Other CCR RB80 / Clone Other SCR Home Build Other Rebreather/s: Other CCR RB80 / Clone Other SCR Home Build Join Date: Jun 2005 Location: USA Posts: 481	Re: Dual Pony Tanks? or isolators on both sides? Golem Gear, Inc. - LOLA Universal DIN Valve __________________ Jakub Golem Gear ShopKeeper www.golemgear.com
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15th November 2007, 17:38	#25 (permalink)
firemandiver Let's Go Diving! Current Rebreather/s: Dolphin Home Build Other Rebreather/s: Dolphin Home Build Join Date: Sep 2007 Location: gulfport, ms Posts: 165	Re: Dual Pony Tanks? I had originally thought about trying to use a "doubles" manifold, but there are a few inherent problems with that idea. 1) The Dolphin is 18 or so inches wide, so the isolator/tie bar would have to be custom made if that's even possible. 2) The tie bar/valve assy would certainly interfere with the connection of the hoses, Oxy2, and OPV. I do like the LOLA valve, though. Perhaps I could devise a crossover using that on the main tank and a standard din valve on tank 2. Plumb the crossover with 1/4 ss line and bend/route it so it does not interfere with the hoses and such. That may be a possibility. I'll contact Golem and pick their brains a little. Thanks, FD.
(Online)

15th November 2007, 19:41	#26 (permalink)
Freef Custom Title Disallowed! Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Jan 2006 Location: Land of the Freef, UK. Posts: 1,356	Re: Dual Pony Tanks? There wouldn't be a problem with a long bar, especially with an offset isolator, it's just a bit of turned stailless with the right threads and 'O' rings, a competent engineering company could knock one up for you. The downside is the length, and the risk of damage to the manifold if it gets knocked. __________________ David. Currently owner of two differently sized ankles.
(Offline)

21st November 2007, 15:10	#27 (permalink)
jaap Normal people worry me Current Rebreather/s: Classic Kiss Other CCR RB80 / Clone Ray Other SCR Home Build Other Rebreather/s: Other CCR RB80 / Clone Ray Other SCR Home Build Join Date: Jun 2005 Location: Stockholm Sweden Posts: 451	Re: Dual Pony Tanks? Quote: (Originally Posted by firemandiver) I had originally thought about trying to use a "doubles" manifold, but there are a few inherent problems with that idea. 1) The Dolphin is 18 or so inches wide, so the isolator/tie bar would have to be custom made if that's even possible. 2) The tie bar/valve assy would certainly interfere with the connection of the hoses, Oxy2, and OPV. I do like the LOLA valve, though. Perhaps I could devise a crossover using that on the main tank and a standard din valve on tank 2. Plumb the crossover with 1/4 ss line and bend/route it so it does not interfere with the hoses and such. That may be a possibility. I'll contact Golem and pick their brains a little. Thanks, FD. You could use valves with dual exits, like H-valves or better the LOLA or Aircon dual valves. Then simply get a transfill whip of approx apropriate lenght w/o gauge. Connect the cylinders and you have a flexible manifold system with two isolators. As a bonus you can separate filled tanks for transport and get a fill whip. If you go for that just make sure you get a whip with a reliable bleeder valve given it will be important that it does not leak. Something like this whip: http://www.oceanictech.se/images/pro...aver-10895.jpg __________________ My initials: JAAP
(Online)

22nd November 2007, 00:52	#28 (permalink)
4ster Steve Sprague Current Rebreather/s: rEvo Other Rebreather/s: rEvo Join Date: Mar 2006 Location: Arlington, Washington Posts: 295	Re: Dual Pony Tanks? This is a different approach to what you are trying to do. Don't connect them. Instead run the first stage on your left shoulder to one of the combo BC inflator/regulator things. On your right shoulder run a standard octopus. Simpler than connecting them together and it eliminates a potential failure point. Just a thought. __________________ Steve "My problem is that I have trouble reconciling my gross habits with my net income." Errol Flynn
(Offline)

22nd November 2007, 01:40	#29 (permalink)
firemandiver Let's Go Diving! Current Rebreather/s: Dolphin Home Build Other Rebreather/s: Dolphin Home Build Join Date: Sep 2007 Location: gulfport, ms Posts: 165	Re: Dual Pony Tanks? Thought about that as well. Already using an Air2. Was just trying to eliminate the 2nd complete system. In no hurry to do this, just looking at all angles. Thanks, FD
(Online)

21st December 2007, 03:17	#30 (permalink)
fltekdiver Rebreather World Writer Current Rebreather/s: Sport Kiss Dolphin Other Rebreather/s: Dolphin Join Date: Jun 2005 Location: USA- Florida Posts: 54	Re: Dual Pony Tanks? I heard somone say you can flip the two tanks upside down, and being I'm a photographer, I really dont want to sling my bail out. I'm currentley using a 13cf tank on my left side for B/C and dry suit inflation, a 13cf tank on my right side, slinging under my right arm, strickley for bail out, for 60' or less FSW, and I use a 19cf for 100' or less, and a 27cf tank on the lower rear for breathing gas. I would love to mount both 13's on the side of my shell upside down, and have the 27cf as breathing gas ony. This is a great thread, I'm to stuck in the same situation.
(Offline)

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