Mystery Tank...

[scubapeter]

Soo... Late last fall, I happened into a very large and heavy Heiser cylinder. The tank had been stored in a closet for many years and the former owner was not a diver. She wanted the tank gone and I bought it for what I believed to be a great deal. It had a 500 psi storage fill. I took the tank home and examined it. It is a 2400 psi Heiser, 8 inches in diameter and about 30 inches tall without a valve. The empty weight of the tank was 57 pounds with a valve. The initial hydro date is 1998 and the only subsequent is 2003. A quick visual inspection revealed that the interior is perfect. I took the tank to my hydro facility and she passed with flying colors.

I searched the internet and found nothing to support that this tank ever existed. Most of the information I read was in regards to the Heiser 140 and 190 cu ft tanks which were described as dangerously negative.

I filled the tank to 2640 and noted the weight as approximately 66 pounds. Given the added weight of 9 pounds of air, I divided by 0.0807 which would indicate that this tank holds 111.5 cu ft. of air at the service pressure plus ten percent.

So I had to see if this tank was so dangerously negative. I took it diving in fresh/shallow water. 3mm wetsuit, aluminum bp/w, no added weights. While I did add some air to the bc, it was not much. I still think this tank is huge for 111 cu ft of air, but I also may put it into my dive rotation.

Has anyone else owned one of these tanks or have any information on them? Thanks!!

Pete

 

[scubadiver888]

Sounds like you found a Heiser 104: Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan

 

[zider]

Sizes match dead on with a Heiser HP140 but the chart from Huron Scuba doesn't mention a LP version for this tank.

Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan

 

[Bob DBF]

I have found that there is no comprehensive list of tanks. Huron and Indian Valley lists are good but may miss an odd small run tank the compiler has never seen or ran across the mfg literature. I know they are not regularly updated as the new Fabers are not included. The venerable old steel 72 is not there either.

You may have just run across a tank with a low production numbers.

Good luck

Bob

 

[scubapeter]

Thanks for the replies.... Its too tall and heavy to be a 104 and too light and low pressure to be a 140....

 

[halocline]

The easiest way to accurately get it's capacity would be to fill it with water, measure the volume, and then do the math. But you might also try transfilling a known tank from it. For example, if you start it full (2640) and fill an empty 100 cft tank from it, wait until they equalize, then you can calculate how much air is in the 100. That's how much air left the big tank. (Let's say the 100 ended up with 30cft) So now you know that whatever the pressure dropped in the big tank equals 30cft, and that should allow you to get volume at 2640.

I think this works, if not I'm sure someone will correct me!

 

[scubafanatic]

I'd suggest asking your hydro facility what they know about the tank.

 

[Jack Hammer]

Surprised no one's suggested trying to use the tank neck numbers.

 

[scubapeter]

The easiest way to accurately get it's capacity would be to fill it with water, measure the volume, and then do the math. But you might also try transfilling a known tank from it. For example, if you start it full (2640) and fill an empty 100 cft tank from it, wait until they equalize, then you can calculate how much air is in the 100. That's how much air left the big tank. (Let's say the 100 ended up with 30cft) So now you know that whatever the pressure dropped in the big tank equals 30cft, and that should allow you to get volume at 2640.

I think this works, if not I'm sure someone will correct me!

I just so happen to have a steel 100 so this would make for some easy math... I'm going to give this a try, thanks for the idea.

 

[widget]

Its a tank Heiser made for the French diving company Beuchat and was sold in small quantities into the USA market via Beuchat USA in the 90's. In metric its an 18 litre cylinder. Its original colour was a light grey.

They were very heavy, and some had a convex bottom so no boot was required, Heiser made lighter cylinders as well so its likely it was a spec requirement at the time. Needless to say, Heiser made solid cylinder's, quality will never be an issue, its big and heavy but if you can handle the weight its a good solid cylinder.