Help identifying this cylinder please.

Jimmer · 24th September 2007, 01:41

I picked up this never used cylinder off ebay from a Military Surplus store, advertised as a rebreather O2 bottle, originally thinking of using it for drysuit inflation. When it got here, I realized it had a tapered thread, and not a standard 1/2" NPT that most threaded scuba cylinders used. It appears to possibly be a 3/8" NPT, or maybe a BSP pipe thread. A 3/8" NPT hose barb threaded into it, but felt very sloppy. The cylinder pressure rating is 2850+, and it has both DOT and TC stamps, and was manufactured by PST. I emailed the surplus place I got it from, and he has no idea what military this would have been used by, but the DOT and TC stamps made me assume it was North American.

Can anyone help me identify A: what military would have used this and in what rebreather? and B: are there commercially available valves for this, or should I just scrap it and get a cylinder with a regular 3/4 NPSM O-ring?

Thanks,
Jim

S. Marc · 24th September 2007, 01:51

Hi,

It looks very similar if not the same as the steel 02 cylinders you get with Biopak 60 terrestial mine rescue and hazmat rebreathers.

I got rid of all the Biopak cylinders that came with the biopaks I purchased as normal scuba tank valves didn't fit the tanks and scuba 1st stages didn't work with their tank valves.

Marc

***ScubaDadMiami*** · 24th September 2007, 02:48

The calipers are blocking the information from the tank neck. I suspect that the answer to your question lies right after where the M starts. The M denotes medical use. So, you can probably go to the manufacturer's site and find the answer there.

zoo_diver · 24th September 2007, 04:04

Word -- take another shot so we can get a full view of the numbers on the tank.

Jimmer · 24th September 2007, 04:45

Here is the complete list of what is stamped on the cylinder

DOT-3AA2850 10-00+ (then a star)
IA 714953
81

TC-3AA M219
10IA00
81
REE 10.5

UKSteve · 24th September 2007, 09:39

Quote: (Originally Posted by S. Marc)

Hi,

It looks very similar if not the same as the steel 02 cylinders you get with Biopak 60 terrestial mine rescue and hazmat rebreathers.

I got rid of all the Biopak cylinders that came with the biopaks I purchased as normal scuba tank valves didn't fit the tanks and scuba 1st stages didn't work with their tank valves.

Marc

To me the thickness of the neck strongly suggests an aluminium cylinder but I could be very wrong!!.... tapered thread too so beware!!

Steve

JCdesign97 · 24th September 2007, 12:05

It may not be the same tapered thread as your tank, but I recall a few years ago Northeast Scuba Supply in Trooper, PA, USA had a run of either K and/or DIN valves cut with a tapered pipe thread to go along with a series of steel tanks that had the same. I don't know if they still have any or if it's the same thread, but it may be worth giving them a call. 1.610.631.2288 - ask for John.

Good luck!

O.C.Diver · 24th September 2007, 12:07

Quote: (Originally Posted by UKSteve)

To me the thickness of the neck strongly suggests an aluminium cylinder but I could be very wrong!!.... tapered thread too so beware!!

Steve

Nope. 3AA in the USA DOT system is a steel tank.

I would carry the tank to a USA hydrostatic testing facility and see if they can match the thread to one of their testing adapters.

Ted

n2diving · 24th September 2007, 13:45

The cylinder was manufactured by Pressed Steel Tank (now defunct). The manufacture of custom natural gas and aircraft specialty cylinders, along with scuba cylinders was a core business for PST. Their website appears to still function and the product description page for this cylinder is at www.pressedsteel.com/page6.html

It is steel (DOT-3AA series), the service pressure for use in the U.S. is 3135 psi (2850 + 10%). The hydro test was done in October 2000 and the "star" indicates the cylinder qualifies for a ten year hydro retest cycle (i.e. the walls are very thick). The rejection elastic expansion (REE) value is 10.5 cc. (The REE value is used by subsequent testers to determine if the cylinder still qualifies for a +10% overfill.) The IA over the 81 is the Independent Inspection Agency hydro testers identification. The cylinder serial number is 714953. In the photo you can see the PST logo symbol following the serial number.

The cylinder is also suitable for use in Canada (TC-3AAM series) and can be filled to 219 BAR there. The hydro test date appears again under the TC-3AAM stamp with the testers identfication (the IA over the 81) between the month and the year. It reappears there because the Transport Canada regs differ from the DOT regarding the plus and star symbols.

This cylinder is for use in aircraft to supply breathing gas to pilot and/or passengers in the event of an emergency. The typical use for the cylinder is to be permanently affixed inside the aircraft and plumbed into an on-board supply system (the reason for the tapered threads). Not suitable for use in scuba. There is no particular reason to think this cylinder was for oxygen service (i.e. the green paint is meaningless), and so it's almost certainly not O2 clean.

**Freef** · 24th September 2007, 13:45

Quote: (Originally Posted by UKSteve)

To me the thickness of the neck strongly suggests an aluminium cylinder but I could be very wrong!!.... tapered thread too so beware!!

Steve

Allys usually have flat bottoms, steel rounded. The neck of a tank is also thicker than the body due to the manufacturing process.

24th September 2007, 01:51	#2 (permalink)
S. Marc Custom Title Allowed! Current Rebreather/s: MK 15.X Home Build Other Rebreather/s: Not Bought Yet Home Build Join Date: Dec 2005 Posts: 199	Re: Help identifying this cylinder please. Hi, It looks very similar if not the same as the steel 02 cylinders you get with Biopak 60 terrestial mine rescue and hazmat rebreathers. I got rid of all the Biopak cylinders that came with the biopaks I purchased as normal scuba tank valves didn't fit the tanks and scuba 1st stages didn't work with their tank valves. Marc
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24th September 2007, 02:48	#3 (permalink)
*ScubaDadMiami* Moderator Current Rebreather/s: Optima Other Rebreather/s: Join Date: Sep 2005 Location: Florida, USA Posts: 2,132	Re: Help identifying this cylinder please. The calipers are blocking the information from the tank neck. I suspect that the answer to your question lies right after where the M starts. The M denotes medical use. So, you can probably go to the manufacturer's site and find the answer there. __________________ Howard Packer IANTD CCR Instructor Miami Beach, Florida CCRDiveTraining.com
(Online)

24th September 2007, 04:45	#5 (permalink)
Jimmer New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Dec 2006 Location: Ontario, Canada Posts: 72	Re: Help identifying this cylinder please. Here is the complete list of what is stamped on the cylinder DOT-3AA2850 10-00+ (then a star) IA 714953 81 TC-3AA M219 10IA00 81 REE 10.5
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24th September 2007, 09:39	#6 (permalink)
UKSteve Steve Collard Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Jul 2005 Location: Weymouth, UK Posts: 598	Re: Help identifying this cylinder please. Quote: (Originally Posted by S. Marc) Hi, It looks very similar if not the same as the steel 02 cylinders you get with Biopak 60 terrestial mine rescue and hazmat rebreathers. I got rid of all the Biopak cylinders that came with the biopaks I purchased as normal scuba tank valves didn't fit the tanks and scuba 1st stages didn't work with their tank valves. Marc To me the thickness of the neck strongly suggests an aluminium cylinder but I could be very wrong!!.... tapered thread too so beware!! Steve
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24th September 2007, 12:05	#7 (permalink)
JCdesign97 My unit can beat up yours Current Rebreather/s: Optima Other Rebreather/s: Join Date: Mar 2007 Location: PA, USA Posts: 385	Re: Help identifying this cylinder please. It may not be the same tapered thread as your tank, but I recall a few years ago Northeast Scuba Supply in Trooper, PA, USA had a run of either K and/or DIN valves cut with a tapered pipe thread to go along with a series of steel tanks that had the same. I don't know if they still have any or if it's the same thread, but it may be worth giving them a call. 1.610.631.2288 - ask for John. Good luck! __________________ Cheers, John Cogan
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24th September 2007, 12:07	#8 (permalink)
O.C.Diver Helium Addict Current Rebreather/s: Classic Kiss Other CCR Home Build Other Rebreather/s: Not Bought Yet Other CCR Home Build Join Date: Mar 2006 Location: Salisbury MD USA Summers; Wandering Florida Winters Posts: 220	Re: Help identifying this cylinder please. Quote: (Originally Posted by UKSteve) To me the thickness of the neck strongly suggests an aluminium cylinder but I could be very wrong!!.... tapered thread too so beware!! Steve Nope. 3AA in the USA DOT system is a steel tank. I would carry the tank to a USA hydrostatic testing facility and see if they can match the thread to one of their testing adapters. Ted __________________ Consider this my opinion.......sometimes I'm even right, but remember.........YMMV. Ted Green Charter Boat "OC Diver" http://www.ocdiver.com
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24th September 2007, 13:45	#9 (permalink)
n2diving Custom Title Allowed! Current Rebreather/s: Optima Other CCR Other Rebreather/s: Inspiration Classic Other CCR Join Date: Feb 2005 Location: Florida, USA Posts: 272	Re: Help identifying this cylinder please. The cylinder was manufactured by Pressed Steel Tank (now defunct). The manufacture of custom natural gas and aircraft specialty cylinders, along with scuba cylinders was a core business for PST. Their website appears to still function and the product description page for this cylinder is at www.pressedsteel.com/page6.html It is steel (DOT-3AA series), the service pressure for use in the U.S. is 3135 psi (2850 + 10%). The hydro test was done in October 2000 and the "star" indicates the cylinder qualifies for a ten year hydro retest cycle (i.e. the walls are very thick). The rejection elastic expansion (REE) value is 10.5 cc. (The REE value is used by subsequent testers to determine if the cylinder still qualifies for a +10% overfill.) The IA over the 81 is the Independent Inspection Agency hydro testers identification. The cylinder serial number is 714953. In the photo you can see the PST logo symbol following the serial number. The cylinder is also suitable for use in Canada (TC-3AAM series) and can be filled to 219 BAR there. The hydro test date appears again under the TC-3AAM stamp with the testers identfication (the IA over the 81) between the month and the year. It reappears there because the Transport Canada regs differ from the DOT regarding the plus and star symbols. This cylinder is for use in aircraft to supply breathing gas to pilot and/or passengers in the event of an emergency. The typical use for the cylinder is to be permanently affixed inside the aircraft and plumbed into an on-board supply system (the reason for the tapered threads). Not suitable for use in scuba. There is no particular reason to think this cylinder was for oxygen service (i.e. the green paint is meaningless), and so it's almost certainly not O2 clean. Last edited by n2diving : 24th September 2007 at 15:36.
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24th September 2007, 13:45	#10 (permalink)
Freef Custom Title Disallowed! Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Jan 2006 Location: Land of the Freef, UK. Posts: 1,353	Re: Help identifying this cylinder please. Quote: (Originally Posted by UKSteve) To me the thickness of the neck strongly suggests an aluminium cylinder but I could be very wrong!!.... tapered thread too so beware!! Steve Allys usually have flat bottoms, steel rounded. The neck of a tank is also thicker than the body due to the manufacturing process. __________________ David. Currently owner of two differently sized ankles.
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