Spheres

cool_hardware52 · 15th November 2007, 22:21

I can't be the first to contemplate this.....

I don't know what the limits are on size and weight for these sphere's is, but I occurs to me that one could cut the near spherical "bottom" off a steel tank, and also cut the pseudo spherical top off the same tank and weld these two pieces together. (Includes a nice threaded opening for a conventional Scuba valve at no additional cost

)

Given that tanks are thicker at the bottom, and crown your resultant "sphere" will likely be heavy, but the added thickness makes for fairly easy weld.

steel 46's are 5.5" dia, 72's are 6.9" dia, 85's are 7.0" 95's are 8".........

Tobin

teksimple · 16th November 2007, 01:26

Sounds like a great idea. But uh, did you think about the neck for the valve? Not to mention tapping the thing with the proper threads. But go nuts. Please let us know how it works out!

cool_hardware52 · 16th November 2007, 01:55

Quote: (Originally Posted by teksimple)

Sounds like a great idea. But uh, did you think about the neck for the valve? Not to mention tapping the thing with the proper threads. But go nuts. Please let us know how it works out!

I'll be the first to admit that I'm pretty ignorant about the actual spheres used in the 15 / 15.5 / 16 in terms of size, weight, and thread size, space available, other interference considerations etc. My repsonses here have been more on the lines of how I might approach the problem from a manufacturing perspective.

If it is possible / practical to use a 3/4 scuba valve the tank necks would have these already in place.

Tobin

hoppyinca · 16th November 2007, 02:17

Quote: (Originally Posted by SimonK)

...titanium pressure vessels ...controlled by American boiler specs ...

ASME - American Society of Mechanical Engineers?

I currently inspect boilers and pressure vessels for a living... well, for money anyway (hate it when a shop tells me I can not VIP my own tanks!).

I currently have steels, in need of tumbling, and sitll have most of the original white epoxy-like coating... I would definitely be in for getting some new spheres at a price which would not require me to caugh up a nut!
favoriteRmInHse_dualMk15.jpg

hoppy

cool_hardware52 · 16th November 2007, 02:50

Kinda snug. Thanks for the pics.

Tobin

koputai · 17th November 2007, 00:57

Quote: (Originally Posted by caveseeker7)

Before (and maybe since) the MK15 the flasks were made of steel.
Doesn't Jason have them in his? I've seen two or three CCR1000/MK15 divers using them.

I have a set of each, steels and Inconels.
I bought the old steels in a very delapidated state, and I'm pretty sure they weren't breather ones, as they're slightly smaller and have a different thread size to the normally seen steels. The steel is 4130 CrMo.
Here's the page on my spheres refurb, highly recommended reading!!
Mk15 Spheres

Personally, I wouldn't go anywhere near a sphere that's been machined from a block. A machined one will have so many possible fracture points that it is more likely than not to go pop. I've used a lot of cnc'd parts on various race bikes, and every one eventually fails. To make one taht's safe enough it would have to have an inch of wall thickness, weigh an absolute ton, and hold bugger all gas.

Cheers,
Jason.

cool_hardware52 · 17th November 2007, 01:19

Quote: (Originally Posted by koputai)

Personally, I wouldn't go anywhere near a sphere that's been machined from a block. A machined one will have so many possible fracture points that it is more likely than not to go pop. I've used a lot of cnc'd parts on various race bikes, and every one eventually fails. To make one taht's safe enough it would have to have an inch of wall thickness, weigh an absolute ton, and hold bugger all gas.

I don't know about an inch wall thickness, but I too am not thrilled with the idea of machining from billet. Forming or drawing will produce a much better grain structure.

Tobin

Drmike · 17th November 2007, 01:30

Quote: (Originally Posted by cool_hardware52)

I can't be the first to contemplate this.....

I don't know what the limits are on size and weight for these sphere's is, but I occurs to me that one could cut the near spherical "bottom" off a steel tank, and also cut the pseudo spherical top off the same tank and weld these two pieces together. (Includes a nice threaded opening for a conventional Scuba valve at no additional cost

)

Given that tanks are thicker at the bottom, and crown your resultant "sphere" will likely be heavy, but the added thickness makes for fairly easy weld.

steel 46's are 5.5" dia, 72's are 6.9" dia, 85's are 7.0" 95's are 8".........

Tobin

there are far more fun ways to kill yourself!

Dont go there!

Actually if you are desperate you can maybe just buy an accumilator shell theres bunch of mnf around, some are near spherical but many lower pressure. They are mostly welded steel shells (just not spherical) some come with liners (bladder accumilators) you may have issues with threads and sealing valves but should be doable....they will likely be very heavy though

deanc · 17th November 2007, 13:32

Crikey fellas.

Do any of these spook you?

Pressure vessel registration
Pressure vessel design registration
Third party design validation
Manufacturers Data Report
Statement from importer/manufacturer
Non destructive testing
Hydrostatic pressure testing
Weld procedure qualifaction
Welder certification
Acceptable material specifications
Design tensile strength
Welded joint efficiencies
Heat affected zones
Stress concentrations
Class of vessel
Corrosion allowance
Thick walled spherical shells under internal pressure
Gas cylinder code
ASME, ASTM, ANSI, AS, BS
Chartered status
Department of Industry and Resources
Public liability insurance
Duty of care
Legislation
Acts of parliament

Perhaps mastering most of the above before giving it a go.

Like hydro testing for instance, the back yard scuba hydro really comes nowhere near what a NATA certified hydro test thats used pipe/vessel industy wide for commissioning really is -- far superior and quite an engineering analysis in itself. Materials and the actual design is a whole ball game too.

The big picture is far from machine-weld-hydro-> good to go.

cool_hardware52 · 17th November 2007, 13:38

Quote: (Originally Posted by deanc)

Crikey fellas.

Do any of these spook you?

Pressure vessel registration
Pressure vessel design registration
Third party design validation
Manufacturers Data Report
Statement from importer/manufacturer
Non destructive testing
Hydrostatic pressure testing
Weld procedure qualifaction
Welder certification
Acceptable material specifications
Design tensile strength
Welded joint efficiencies
Heat affected zones
Stress concentrations
Class of vessel
Corrosion allowance
Thick walled spherical shells under internal pressure
Gas cylinder code
ASME, ASTM, ANSI, AS, BS
Chartered status
Department of Industry and Resources
Public liability insurance
Duty of care
Legislation
Acts of parliament

Perhaps mastering most of the above before giving it a go.

Like hydro testing for instance, the back yard scuba hydro really comes nowhere near what a NATA certified hydro test thats used pipe/vessel industy wide for commissioning really is -- far superior and quite an engineering analysis in itself. Materials and the actual design is a whole ball game too.

The big picture is far from machine-weld-hydro-> good to go.

Yes every damn one concerns me. Probably why nobody is doing it. Pretty much anybody with the means to attempt it knows better, or has assets to protect.

OTOH, that doesn't mean it can't be done.

Tobin

15th November 2007, 22:21	#41 (permalink)
cool_hardware52 RebreatherWorld Sponsor Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Mar 2005 Location: SoCal USA Posts: 385	Re: Spheres I can't be the first to contemplate this..... I don't know what the limits are on size and weight for these sphere's is, but I occurs to me that one could cut the near spherical "bottom" off a steel tank, and also cut the pseudo spherical top off the same tank and weld these two pieces together. (Includes a nice threaded opening for a conventional Scuba valve at no additional cost) Given that tanks are thicker at the bottom, and crown your resultant "sphere" will likely be heavy, but the added thickness makes for fairly easy weld. steel 46's are 5.5" dia, 72's are 6.9" dia, 85's are 7.0" 95's are 8"......... Tobin __________________ www.deepseasupply.com
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16th November 2007, 01:26	#42 (permalink)
teksimple Enlightened Alpinist Current Rebreather/s: MK 15.X Other Rebreather/s: Sport Kiss Classic Kiss Join Date: Apr 2005 Location: Back in Hawaii Posts: 503	Re: Spheres Sounds like a great idea. But uh, did you think about the neck for the valve? Not to mention tapping the thing with the proper threads. But go nuts. Please let us know how it works out! __________________ ---- _____________ "I don't know the percentage of the Internet that's valid, do you? Jesus, it's scary." - Hunter S. Thompson
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16th November 2007, 01:55	#43 (permalink)
cool_hardware52 RebreatherWorld Sponsor Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Mar 2005 Location: SoCal USA Posts: 385	Re: Spheres Quote: (Originally Posted by teksimple) Sounds like a great idea. But uh, did you think about the neck for the valve? Not to mention tapping the thing with the proper threads. But go nuts. Please let us know how it works out! I'll be the first to admit that I'm pretty ignorant about the actual spheres used in the 15 / 15.5 / 16 in terms of size, weight, and thread size, space available, other interference considerations etc. My repsonses here have been more on the lines of how I might approach the problem from a manufacturing perspective. If it is possible / practical to use a 3/4 scuba valve the tank necks would have these already in place. Tobin __________________ www.deepseasupply.com
(Offline)

16th November 2007, 02:17	#44 (permalink)
hoppyinca New Member Current Rebreather/s: MK 15.X Other Rebreather/s: Join Date: Jun 2005 Location: Laguna Niguel, CA USA Posts: 252	Re: Spheres Quote: (Originally Posted by SimonK) ...titanium pressure vessels ...controlled by American boiler specs ... ASME - American Society of Mechanical Engineers? I currently inspect boilers and pressure vessels for a living... well, for money anyway (hate it when a shop tells me I can not VIP my own tanks!). I currently have steels, in need of tumbling, and sitll have most of the original white epoxy-like coating... I would definitely be in for getting some new spheres at a price which would not require me to caugh up a nut! favoriteRmInHse_dualMk15.jpg hoppy
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16th November 2007, 02:50	#45 (permalink)
cool_hardware52 RebreatherWorld Sponsor Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Mar 2005 Location: SoCal USA Posts: 385	Re: Spheres Kinda snug. Thanks for the pics. Tobin __________________ www.deepseasupply.com
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17th November 2007, 00:57	#46 (permalink)
koputai Subsea Systems Current Rebreather/s: MK 15.X Other CCR Other SCR Other Rebreather/s: Not Bought Yet Other CCR Other SCR Join Date: Jul 2005 Location: Sydney, Australia Posts: 340	Re: Spheres Quote: (Originally Posted by caveseeker7) Before (and maybe since) the MK15 the flasks were made of steel. Doesn't Jason have them in his? I've seen two or three CCR1000/MK15 divers using them. I have a set of each, steels and Inconels. I bought the old steels in a very delapidated state, and I'm pretty sure they weren't breather ones, as they're slightly smaller and have a different thread size to the normally seen steels. The steel is 4130 CrMo. Here's the page on my spheres refurb, highly recommended reading!! Mk15 Spheres Personally, I wouldn't go anywhere near a sphere that's been machined from a block. A machined one will have so many possible fracture points that it is more likely than not to go pop. I've used a lot of cnc'd parts on various race bikes, and every one eventually fails. To make one taht's safe enough it would have to have an inch of wall thickness, weigh an absolute ton, and hold bugger all gas. Cheers, Jason.
(Offline)

17th November 2007, 01:19	#47 (permalink)
cool_hardware52 RebreatherWorld Sponsor Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Mar 2005 Location: SoCal USA Posts: 385	Re: Spheres Quote: (Originally Posted by koputai) Personally, I wouldn't go anywhere near a sphere that's been machined from a block. A machined one will have so many possible fracture points that it is more likely than not to go pop. I've used a lot of cnc'd parts on various race bikes, and every one eventually fails. To make one taht's safe enough it would have to have an inch of wall thickness, weigh an absolute ton, and hold bugger all gas. I don't know about an inch wall thickness, but I too am not thrilled with the idea of machining from billet. Forming or drawing will produce a much better grain structure. Tobin __________________ www.deepseasupply.com
(Offline)

17th November 2007, 01:30	#48 (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: 3,323	Re: Spheres Quote: (Originally Posted by cool_hardware52) I can't be the first to contemplate this..... I don't know what the limits are on size and weight for these sphere's is, but I occurs to me that one could cut the near spherical "bottom" off a steel tank, and also cut the pseudo spherical top off the same tank and weld these two pieces together. (Includes a nice threaded opening for a conventional Scuba valve at no additional cost) Given that tanks are thicker at the bottom, and crown your resultant "sphere" will likely be heavy, but the added thickness makes for fairly easy weld. steel 46's are 5.5" dia, 72's are 6.9" dia, 85's are 7.0" 95's are 8"......... Tobin there are far more fun ways to kill yourself! Dont go there! Actually if you are desperate you can maybe just buy an accumilator shell theres bunch of mnf around, some are near spherical but many lower pressure. They are mostly welded steel shells (just not spherical) some come with liners (bladder accumilators) you may have issues with threads and sealing valves but should be doable....they will likely be very heavy though __________________ Cave diving is a sport Wreck diving is a sport Diving in general is a sport 'Rebreather diving' is not a sport its the delusional obsession with a highly dangerous and often inappropriate piece of equipment
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17th November 2007, 13:32	#49 (permalink)
deanc New Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Dec 2006 Location: Perth, WA Posts: 52	Re: Spheres Crikey fellas. Do any of these spook you? Pressure vessel registration Pressure vessel design registration Third party design validation Manufacturers Data Report Statement from importer/manufacturer Non destructive testing Hydrostatic pressure testing Weld procedure qualifaction Welder certification Acceptable material specifications Design tensile strength Welded joint efficiencies Heat affected zones Stress concentrations Class of vessel Corrosion allowance Thick walled spherical shells under internal pressure Gas cylinder code ASME, ASTM, ANSI, AS, BS Chartered status Department of Industry and Resources Public liability insurance Duty of care Legislation Acts of parliament Perhaps mastering most of the above before giving it a go. Like hydro testing for instance, the back yard scuba hydro really comes nowhere near what a NATA certified hydro test thats used pipe/vessel industy wide for commissioning really is -- far superior and quite an engineering analysis in itself. Materials and the actual design is a whole ball game too. The big picture is far from machine-weld-hydro-> good to go. __________________ You dont know what you dont know.
(Online)

17th November 2007, 13:38	#50 (permalink)
cool_hardware52 RebreatherWorld Sponsor Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Mar 2005 Location: SoCal USA Posts: 385	Re: Spheres Quote: (Originally Posted by deanc) Crikey fellas. Do any of these spook you? Pressure vessel registration Pressure vessel design registration Third party design validation Manufacturers Data Report Statement from importer/manufacturer Non destructive testing Hydrostatic pressure testing Weld procedure qualifaction Welder certification Acceptable material specifications Design tensile strength Welded joint efficiencies Heat affected zones Stress concentrations Class of vessel Corrosion allowance Thick walled spherical shells under internal pressure Gas cylinder code ASME, ASTM, ANSI, AS, BS Chartered status Department of Industry and Resources Public liability insurance Duty of care Legislation Acts of parliament Perhaps mastering most of the above before giving it a go. Like hydro testing for instance, the back yard scuba hydro really comes nowhere near what a NATA certified hydro test thats used pipe/vessel industy wide for commissioning really is -- far superior and quite an engineering analysis in itself. Materials and the actual design is a whole ball game too. The big picture is far from machine-weld-hydro-> good to go. Yes every damn one concerns me. Probably why nobody is doing it. Pretty much anybody with the means to attempt it knows better, or has assets to protect. OTOH, that doesn't mean it can't be done. Tobin __________________ www.deepseasupply.com
(Offline)

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