GTA
Support Equipment For PCP/HPA/CO2 and springers ,rams => Support Equipment For PCP/HPA/CO2 => Topic started by: Gertrude on November 27, 2015, 04:09:10 AM
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hey all,
Wondering if anyone here has purchased/used any of these ?
I was looking around for a 17 cu in / 3000 psi bottle (not very easy to find), when I ran across these Chinese made 4500 psi bottles that may fit the application very nicely.
Fitted with a Ninja ProV2 SHP regulator, I'm guessing these could do very well for a regged HPA conversion ?
http://wholesaler.alibaba.com/search?spm=a2700.7724838.11.4.oSuedV&q=0.35l-30mpa+carbon+fiber+cylinder&pid=60235056810 (http://wholesaler.alibaba.com/search?spm=a2700.7724838.11.4.oSuedV&q=0.35l-30mpa+carbon+fiber+cylinder&pid=60235056810)
They are pretty pricey, ($125) and I'm not sure if that includes shipping.
I did find them at a lower price ($70-$120) ,but for that price, there is a minimum order of 10 pcs.
http://www.alibaba.com/product-detail/Carbon-fiber-scuba-tank-Small-co2_60122288824.html?spm=a2700.7724838.30.154.Cai5J4 (http://www.alibaba.com/product-detail/Carbon-fiber-scuba-tank-Small-co2_60122288824.html?spm=a2700.7724838.30.154.Cai5J4)
So the reason for this thread is to see if anyone here has used one of these bottles ?,
and also to see if there might be an interest in doing a group buy ?
If we can get them for $70 each, I'd be interested in at least 2 of them, (possibly 3 or 4 of them).
what do you guys think ?
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First question is.... are they DOT rated (on the tank) so that you can get them filled?.... If so, I would be interested, depending on landed price.... I see they are 61mm OD, so you would need a deeper drop block, of course.... If going to the trouble of sourcing these, would not a 500 cc tank be more useful?.... What is the thread?.... most likely is 18mm x 1.5mm, not 5/8"-18NF.... I would assume the $70 price is for 200 units, the price for 10 would be $120....
Bob
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Here's another page from the same site where conventional aluminum
bottles are offered.......
http://wholesaler.alibaba.com/product-detail/0-5L-20mpa-Gas-cylinder-seamless_60189366821.html?spm=a2700.7765678.1998649852.5.kYJaEM (http://wholesaler.alibaba.com/product-detail/0-5L-20mpa-Gas-cylinder-seamless_60189366821.html?spm=a2700.7765678.1998649852.5.kYJaEM)
A simple tangential stress calculation of the pictured unit using stress = pressure*ID/2*wall thickness
gives a value of ~18500 psi. The material listed is 6061 which has a minimum tensile strength of 45000 psi.
The safety factor is therefore ~2.4 ........and yet the words "DOT certificate" appear at the bottom of the pic.
Have I missed something here?
Ron
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Here's another page from the same site where conventional aluminum
bottles are offered.......
http://wholesaler.alibaba.com/product-detail/0-5L-20mpa-Gas-cylinder-seamless_60189366821.html?spm=a2700.7765678.1998649852.5.kYJaEM (http://wholesaler.alibaba.com/product-detail/0-5L-20mpa-Gas-cylinder-seamless_60189366821.html?spm=a2700.7765678.1998649852.5.kYJaEM)
A simple tangential stress calculation of the pictured unit using stress = pressure*ID/2*wall thickness
gives a value of ~18500 psi. The material listed is 6061 which has a minimum tensile strength of 45000 psi.
The safety factor is therefore ~2.4 ........and yet the words "DOT certificate" appear at the bottom of the pic.
Have I missed something here?
Ron
If chinese air bottles are anything like chinese steel, you can get them with any paper work you like :)
Mind you that paperwork might have some rather odd grammar and spelling mistakes.
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My understanding is that 2.4:1 using UTS is the accepted safety margin for DOT design of pressure vessels if you use FEA.... for simple calculations it is 3.5:1.... It used to be 4:1 in the days of boilers, but has changed because of advancements in technology.... What surprised me is that the Yield SF is only 1.5:1 (which should pretty much make that irrelevant).... It isn't simple to dig out this information, but that is the best I could find on the subject about a month ago when I was looking around.... Unfortunately, I didn't bookmark the source.... There are other requirements RE Hydrotests, etc. of course.... I could find no reference to using 3:1 to Yield anywhere, which is what I was told to do years ago, the reasoning being that using Yield was safer than using UTS.... For things like CrMoly, with such a wide margin between Yield (63K) and UTS (97K) it makes a big difference in your choice of wall thickness.... I have also found that the proper way to calculate hoop stress is using ID, as you did, and have always done that.... but most of the Barlow's calculators online (but not all) use the OD to add even greater SF....
Bob
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Bob, DOT requires 3.4 based on UTS........not 2.4
Perhaps a typo ?
I ran thru that exercise just to see roughly where the
products stand...........and it looks "iffy" from here.
Ron
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Taken directly out of Appendix 1 of ASME II Part D:
FOR SECTION VIII DIVISION 1 -
The maximum allowable stress shall be the lowest value
obtained from the criteria in Table 1-100. The mechanical
properties considered, and the factors applied to establish
the maximum allowable stresses, are as given below.
(a) At temperatures below the range where creep and
stress rupture strength govern the selection of stresses,
the maximum allowable stress value is the lowest of the
following:
(1) the specified minimum tensile strength at room
temperature divided by 3.5
(2) the tensile strength at temperature divided by 3.5
(3) two-thirds of the specified minimum yield
strength at room temperature
(4) two-thirds of the yield strength at temperature
In the application of these criteria, the Committee considers
the yield strength at temperature to be SYRY, and the
tensile strength at temperature to be 1.1STRT.
Two sets of allowable stress values are provided in
Tables 1A and 1B for austenitic materials and specific
nonferrous alloys. The higher alternative allowable stresses
are identified by a footnote to the tables. These stresses
exceed two-thirds but do not exceed 90% of the minimum
yield strength at temperature. The higher stress values
should be used only where slightly higher deformation is
not in itself objectionable. These higher stresses are not
recommended for the design of flanges or other strain
sensitive applications.
(b) At temperatures in the range where creep and stress
rupture strength govern the selection of stresses, the maximum
allowable stress value for all materials is established
by the Committee not to exceed the lowest of the following:
(1) 100% of the average stress to produce a creep
rate of 0.01%/1,000 hr
(2) 100Favg% of the average stress to cause rupture
at the end of 100,000 hr
(3) 80% of the minimum stress to cause rupture at
the end of 100,000 hr
Stress values for high temperatures are based, whenever
possible, on representative uniaxial properties of the materials
obtained under standard ASTM testing conditions or
equivalent. The stress values are based on basic properties
of the materials and no consideration is given for corrosive
environment, for abnormal temperature and stress conditions,
or for other design considerations.
FOR SECTION VIII DIVISION 2 -
Design stress is the lower of:
Min spec tensile strength / 2.4;
Min spec yield strength / 1.5;
OR
(Min spec yield strength * temperature derating factor) / 1.5;
The Division 2 rules, which were introduced in 2007, are "more onerous" (ie uses more complicated calculations) but allow for higher stress by using Finite Element Analysis.... They were made to make ASME "more competitive" with The European PED Requirements.... Basically, it increases the allowable stress, but requires better calculation of said stress.... Good luck trying to find out much more detail than that online.... ASME want many thousands of dollars for their rulebook.... Interestingly, if you go back far enough, the safety factor was 5:1.... came down to 4:1.... then down to 3.5:1 in 2000 (Div.1) and down to 2.4:1 in 2007 (Div.2).... All I'm saying is that perhaps that is the reason for the low SF that you calculated?....
Bob
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Here's another page from the same site where conventional aluminum
bottles are offered.......
http://wholesaler.alibaba.com/product-detail/0-5L-20mpa-Gas-cylinder-seamless_60189366821.html?spm=a2700.7765678.1998649852.5.kYJaEM (http://wholesaler.alibaba.com/product-detail/0-5L-20mpa-Gas-cylinder-seamless_60189366821.html?spm=a2700.7765678.1998649852.5.kYJaEM)
A simple tangential stress calculation of the pictured unit using stress = pressure*ID/2*wall thickness
gives a value of ~18500 psi. The material listed is 6061 which has a minimum tensile strength of 45000 psi.
The safety factor is therefore ~2.4 ........and yet the words "DOT certificate" appear at the bottom of the pic.
Have I missed something here?
Ron
I brought 20 of these identical bottles into the usa.
They are not DOT, and the company will not make them to DOT standards because it would not be cost effective.. or so that is what the lady from acecare told me.
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"They are not DOT......" thanks for that info, dman1114.
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0.35 liter 300 bar/4500 psi about $155 free shipping
http://www.aliexpress.com/item/High-Quality-SCBA-Cylinder-Carbon-Fiber-Cylinder-Small-Composite-Bottle-PCP-Cylinder-0-35L-Free-Shipping/32621979775.html?spm=2114.01010208.8.4.pMZLVi (http://www.aliexpress.com/item/High-Quality-SCBA-Cylinder-Carbon-Fiber-Cylinder-Small-Composite-Bottle-PCP-Cylinder-0-35L-Free-Shipping/32621979775.html?spm=2114.01010208.8.4.pMZLVi)
0.5 liter
http://www.aliexpress.com/item/TIANHAI-JP-0-36L-0-5L-30MPA-High-pressure-Fiber-Carbon-Fiber-Cylinder/32616327217.html?spm=2114.01010208.8.44.5wIrj2 (http://www.aliexpress.com/item/TIANHAI-JP-0-36L-0-5L-30MPA-High-pressure-Fiber-Carbon-Fiber-Cylinder/32616327217.html?spm=2114.01010208.8.44.5wIrj2)
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Those are all 18 x 1.5mm threads, a Ninja reg. will not fit....
Bob
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JDS airman reg. will fit. 4500/metric outputs up to 3000psi
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JDS airman reg. will fit. 4500/metric outputs up to 2400psi
JDS airman reg. & bottles, it is Chinese?
http://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20160520124127&SearchText=paintball+regulator (http://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20160520124127&SearchText=paintball+regulator)
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JDS airman reg. will fit. 4500/metric outputs up to 2400psi
JDS airman reg. & bottles, it is Chinese?
http://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20160520124127&SearchText=paintball+regulator (http://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20160520124127&SearchText=paintball+regulator)
Is this a question?
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JDS airman reg. will fit. 4500/metric outputs up to 2400psi
JDS airman reg. & bottles, it is Chinese?
http://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20160520124127&SearchText=paintball+regulator (http://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20160520124127&SearchText=paintball+regulator)
Is this a question?
Yes, are Chinese?
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The bottles are and the regs I dont know but heres a link http://www.jdsairman.com/Regs.html (http://www.jdsairman.com/Regs.html)
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It looks like they are Chinese ???
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YES ... JDS regs are a Loose Chinese knockoff of the original basic Ninja regulators.
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Are they a good or bad copy of the original? Do they work ok?
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Are they a good or bad copy of the original? Do they work ok?
They function fine tho IMO use an inferior seat design being a more typical raised surface wedge against flat delrin to Ninjas thinwall tube on a delrin ball which personally feel suffers less pressure creep in set pressure.
JDS would not sell shimming or bevels to readjust pressure as delivered requesting REG be returned to them for adjusting / servicing. * At least that was my dealings with them ???
JMO tho ...
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Not user adjustable was the answer from JDS for me too. I bought the bottle adapter and reg for marauder so I quess I'll find out how it works in a couple of weeks.
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Only acquire or make this part (vice versa) http://www.bestfittings.co.uk/shopexd.asp?id=643 (http://www.bestfittings.co.uk/shopexd.asp?id=643) for this bottle, but it is an additional cost and weight :P, should contact the manufacturer to make 5/8"-18NF thread.
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That adapter is backwards to fit a Nina reg. on those Chinese tanks.... You need 5/8"-18 female, to fit the reg., to 18 x 1.5mm male, to fit into the tank....
Bob
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They are all user adjustable. You have to have a way to check the output of the reg. I have made a few adapters to test regs and set desired pressure.
You can get shims at McMaster Carr. It's funny how the companies all use the same thickness of shim no matter what the set pressure is. I have found that going to the next thicker shim makes a big diffence on how the good the reg works. Able to stack like ()()()()() instead of ((())) or this (((()))).
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It should open new topic, We're off to the Chinese regulators.
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Yes I know they can be adjusted, no mather what the seller says. For me it's a question of which will be a better/safer option: play with the JDS reg to get the needed plenum pressure or disable the JDS reg and use an easily adjustable Huma reg in the remaining marauder airtube. As the only reason I bought the JDS parts is to get the cf bottle fitted to my marauder. It's a bullpup setup so there will be a plenty of plenum size even with the Huma in the remaining airtube.
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Instead of disabling a regulator, just remove it and use an adapter from bottle to gun.... basically a hollow bolt, with a thick enough wall to be safe....
Bob
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Do you know anybody who could make me such an adapter? It is the obvious choice, it could even shave an inch of the oal lenght of the assembly. It would need to have a port for the fill adapter and pressure gage though.
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They are already available.... PM PakProtector, he designed one built into a tank block, which you need to drop the bottle down to clear the barrel....
Bob
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I hesitate on writing this, as it may appear self-serving. That is definitely NOT the intention. I don't sell those tanks, so it's no competition to me. But I MUST say this:
I have purchased just about EVERY 4500 PSI compressor from China, and they were all junk. While individual units of my Alpha and other brands have continued to work, the Quality Control wasn't there and too large a percentage fail. So, what does this have to do with tanks? QUALITY CONTROL!
Simply put, I don't trust their QC, ESPECIALLY for PRESSURE VESSELS. I could have gotten Chinese tanks years ago and saved a bunch, but think about this: "Who are you going to sue if one of those tanks blows up?". If a U.S. tank blows up, you sue the U.S. manufacturer (they have the pockets). You think you can sue someone from Alibaba that is located in China? It ain't gonna happen (if you survive).
Yes, you can flame me all you want if you disagree, but I honestly would not trust any carbon fiber tank from China. Is the savings REALLY worth it?
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It also would be worth contacting a US dealer of these small CF tanks and seeing
if you bought xx tanks in a group buy if they would be willing to give you a one
time discount seems like they might a least give you a small discount for going through them
instead of someone else...?
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I am probably going to get in trouble for saying this, but I am reluctant to purchase anything when I know that it came from across the Pacific. I have had problems with all kinds of plumbing and heating products manufactured over there. Brass fittings cracking from 60 psi water pressure . Steam cast iron base board getting stress cracks in non load bearing areas of the casting cost my boss at the time to replace with US manufactured cast iron base board and we had to re do the entire job at no cost to the customer. I definitely would not trust my life to a HPA vessel charged to 4500 PSI that came from there especially if I was going to rest my hand or cheek against it