Oxygen cylinder pressure

[woodbutcher]

I took my empty 80 lb. cylinder off my cutting torch to town for exchange yesterday. The tech who brought out the replacement noticed the new propane bottle I picked up at Lowe's and said that he fills those bbq grill bottles to 80% which is the maximum allowable. He said the chain stores don't do that because of high temps in transit causing a loss of at least 10%. Yeah, those big companies are sure looking out for the consumer. So, when I got home with my oxygen, I hooked it up and turned it on. The needle went to 1400 lb. I don't do a lot of cutting with the torch, it's probably been 5 years since I bought oxygen, but I thought they charged these things to more than 2000 lb. When I called the supply house, the tech said 1400 is the max charge now. Has something changed? Looks like I could use a smaller gauge. My old one has way too many numbers on it.

 

[Keith Molden]

I don't know about where you are, but here just a couple of weeks ago I got 2100 lbs pressure in my oxygen cylinder when I had it refilled. From what I have always understood a cylinder is full from 1800 to 2200 lbs pressure. An oxygen cylinder won't build up noticeable pressure because the cylinder is either spun or blown so there is very limited friction inside. Just my thoughts, Keith

 

[Richard G.]

2100 here also. Got filled about 2 months ago.
Richard in NW SC

 

[Geo-TH,In]

I noticed that different places that exhcange 20# propane tanks may only fill them to 15#. I have mine filled at TSC where I only pay for what they put in the tank. That way I can get my tanks topped off, cheaper than exchanging them.

There are other places that refill, but TSC is very close.

 

[Wayne in MN]

Is your gauge correct? Try one from a known good unit.

 

[JL Ray]

Can any one tell me? Is the oxygen cylinder oxygen that I use for cutting, the same quality as what is used for a person needing oxygen? I see people hauling around these little tanks. When they get home could they hook up to a big one?

 

[ypop]

oxygen used for person breathing is medical grade
(more pure) for cutting torch may or may not be medical grade.

Oxygen is Oxygen just that for welding it would not need to be as contaminant free as for medial or scuba diving. You could ask welding gas suppler if it was medical grade since some do supply hospitals with their oxygen.
Ypop

 

[PJH]

I have been told by the folks where I exchange my bottles that the new oxygen bottles go to the medical facilities. When the paint gets skinned up a little, they send them out to the welders. Same contents. Take it for what it's worth. My old neighbor, years ago, asked if he could use my oxygen if he ran out in the night and needed some, and of course I told him he could. He never needed it, but it gave him some peace of mind. That was nearly 40 years ago - things have changed.

 

[RodinNS]

We still get 2200# in them here. Are you sure the gauge is correct? I have to change out the gauges every few years on mine...

Rod

 

[RodinNS]

I don't know for sure... but I suspect the main difference between medical O2 and industrial O2 would be the degree of purity testing and the actual cylinders used. You generally see medical O2 in an aluminum cylinder that doesn't have 2" of rust and crap in the bottom of it vs a 90 year old steel cylinder that has more rust and scale inside than you would care to think about...
The main difference I would think would be the frequency and degree of purity testing tho. For our breathing air in the fire service we need to test twice annually at minimum for purity/contamination etc. O2 I'm sure would be stringently tested as well.

Rod

 

[oleclint]

A few yrs. ago, I asked my oxygen supply guy about medical oxygen while he was filling my torch tank. He said that it all comes from the same tank, no difference. Been that way for ever. I wonder if Hospitals have a filter on the tanks they use?

 

[Stan in Oly, WA]

I can't figure out how an inaccurate gauge would have caused the tech at the supply house to tell him that "1400 is the max charge now." Like he was saying that 1400 was the maximum charge on that gauge because he knew it was inaccurate and when it indicated 1400, the tank was actually filled to 2100? That sounds highly unlikely to me.

Stan

 

[NCWayne]

I've swapped out both a large rental tanks and a smaller customer owned tank within the past two months and both were filled to over 2000 psi. I take the tank back and demand that he show you the new 'regulation' preventing them from giving you a full tank as it appears it's nothing but BS to net them more profits.

If he can produce something, please post it here for the rest of us to see.

 

[S2710]

Years ago when I went out and drank too many Barley pops, the next morning I would take a couple of good breaths of pure oxygen from the torch in the shop. Maybe that is the reason I am like I am. LOL

Bob

 

[JOB]

Many years ago I was told that oxygen for welders was 99.9 percent pure oxygen and medical oxygen was 45% pure.

I asked the main man at Oxygen Service in St. Paul MN. what was the difference in medical and welders oxygen and he gave the same reply as ole clint below. It all comes out of the same valve.

I have never received an oxygen tank with less than 2200 PSI, have had a couple with a little more in them.

As for rust in them there should be little to no rust. If there was rust floating around I would think that it would foul up regulators. that is why they do not want you to run them completely empty. They like about 25 PSI left in the tank. If you run them completely empty and leave the valve open the tank can go dead. that is from the rust build up inside. When you hit an empty tank gently with a hammer it will ring. When you hit a dead tank it will go thud or thump.

 

[Chris Jones]

Perhaps 1400 is the max his company will put in your cylinder. He might have even misinterpreted his bosses directive as an industry max vs a company max. Perhaps the company's insurance gave them a better deal on liability ins if they agreed to only fill tanks to 1400. Perhaps it's a local regulation.

The only way you'll get to the bottom of it is a phone call full of calm questions w/o any insinuations of them doing something wrong.

Even places that only put 15 gallons of propane in 20 gallon tanks have it in the fine print somewhere and most do it so they can have a lower cost "refill". So in a sense you get what you pay for--mind you everyone doesn't charge exactly the same per gallon.

 

[JLeus]

Dont confuse compressed breathing air for filling SCBA and SCUBA tanks with compressed oxygen used for torches and medical uses.

 

[dr sportster]

The medical oxygen and the welding are the same . It is about the purity of the bottles. The mask in the hospital controls the percentage of oxygen used by the patient by adding outside air.At AGL Welding supply all the bottles are on the same dock -- medical and welding grades. If you need medical oxygen it is advised to own your own clean bottle .

 

[JOB]

I would think that the clean medical cylinder would accumulate rust build up just as quick as a welding cylinder. I would also guess that a vertical cylinder would settle all the rust and or dirt, if there is any to the bottom of the cylinder. The oxygen leaving the cylinder comes off the top at a very slow rate, and no contaminants in the cylinder should be stirred up.
I don't believe that a medical oxygen cylinder is any cleaner than a welding cylinder. A hospital could have a filter in the line to remove any microscopic particles that could be in the oxygen. Some of the daily air we all breathe is a lot dirtier than anything that could be in an oxygen cylinder.

 

[Owen Aaland]

A propane tank that has a water capacity of 20 gallons is full of propane with 16 gallons. Propane tanks are not supposed to be filled more than 80% water capacity to allow enough room for expansion.

 

[IH2444]

(quoted from post at 14:13:52 12/23/14) Dont confuse compressed breathing air for filling SCBA and SCUBA tanks with compressed oxygen used for torches and medical uses.

Yep scuba is compressed air not pure or blended oxy unless very special application.

 

[60 acre hillside]

When I was teaching welding I picked up several full medical cylinders at State Surplus Property. The only difference was the medical tanks had brass caps to threaded on the valve. The caps were attached with a chain. I taught when changing bottles to CRACK the valve to blow out debris, It was from the textbook.

 

[ypop]

yes Realized my mistake on the SCUBA tank but it was while watching a diving program that I acquired the knowledge for the difference in medical and industrial Oxygen they needed the medical oxygen for some reason weather deep diving or some other reason. they checked and the oxygen they got was the same. thank you for correcting me.
Ypop

 

[midwesternhayfarmer]

At what temperature is a tank considered full?? Doesn't oxygen contract as temperature decreases?? This would reduce the pressure showing on the gage, would it not??

 

[midwesternhayfarmer]

Tanks are rated in cubic feet of volume and not pressure, are they not?? Cubic feet for Oxygen or argon tank being 300,then 200, 150,125,80,60, and smaller ones at places like TSC.

 

[504]

2200@ 70deg. Cold weather will drop your PSI. The only difference between between medical and industrial oxygen is the paper saying you have medical O2(it must be tested at the fill plant).BTW,medical oxygen is a drug and controlled by the FDA,and takes a Rx). All medical oxygen bottles must be painted green,industrial can be painted any color. We use different colors on ours. The reason LP bottles are only filled to 16-17 lb is the OPD fill valves and the law. On some tanks it is imposable to fill them them, OPD shuts the fill valve off early, the other and biggest reason is the law suits from not filling tanks,look at your receipt, you bought a bottle, not 20# of LP.

 

[JMOR]

(quoted from post at 23:42:34 12/23/14) 2200@ 70deg. Cold weather will drop your PSI. The only difference between between medical and industrial oxygen is the paper saying you have medical O2(it must be tested at the fill plant).BTW,medical oxygen is a drug and controlled by the FDA,and takes a Rx). All medical oxygen bottles must be painted green,industrial can be painted any color. We use different colors on ours. The reason LP bottles are only filled to 16-17 lb is the OPD fill valves and the law. On some tanks it is imposable to fill them them, OPD shuts the fill valve off early, the other and biggest reason is the law suits from not filling tanks,look at your receipt, you bought a bottle, not 20# of LP.

ust a couple of reasons not to go to a tractor forum for info on propane, or oxygen for that matter.

"A propane tank that has a water capacity of 20 gallons is full of propane with 16 gallons."

" The reason LP bottles are only filled to 16-17 lb is the OPD fill valves and the law.
"
FACTS:
The B-B-Q 20# tanks are 80% full with 20# of propane. They are 62% full with 16#. OPD does not stop the tank from receiving 20#, regardless of what the check out clerk at Lowes & Home Depot tells you. Why does Blue Rhino & the exchange places only put 16# in them? Profit & what people will pay for convenience. It is pretty simple, folks.
Don't believe all the 'stuff' you hear.

 

[woodbutcher]

That's the way I was taught, also.

 

[woodbutcher]

It could be their company policy, but what it means to me is that I'm paying what I used to pay and receiving less than I used to. I think it's a rip-off.
Butch

 

[woodbutcher]

My gauge is quite old. That's another reason I called the supply house back. But when I was told that 1400 was the max for them, I knew the gauge was accurate.

 

[woodbutcher]

It looks to me like the gauge is accurate. It agrees with what the company says it puts in their bottles.

 

[woodbutcher]

Thanks for all the replies. I thought I remembered correctly that I usually got bottles with 2200 lb. in them. That seems to be the industry standard.

 

[midwesternhayfarmer]

Not trying to pick a fight or anything but did some
research. Liquid propane weighs 4.2 #s per gallon
and it was stated that an empty tank will require
4.7 gallons to be completely full. When I have 22#
tanks filled, they are filled till the overfill
valve shuts off an d usually shows 4 to 4.5 gallons
on the meter. 7 to 7.5 gallons for a 30# tank. So
4.2# x 4.5 = 18.9 #s

 

[IH2444]

(quoted from post at 10:02:38 12/24/14) Not trying to pick a fight or anything but did some
research. Liquid propane weighs 4.2 #s per gallon
and it was stated that an empty tank will require
4.7 gallons to be completely full. When I have 22#
tanks filled, they are filled till the overfill
valve shuts off an d usually shows 4 to 4.5 gallons
on the meter. 7 to 7.5 gallons for a 30# tank. So
4.2# x 4.5 = 18.9 #s

Yep that is why the OPD's were required many were over fillling the tanks and creating a hazardous situation. I have a 300 gal propane tank but it only actually holds about 285 gallons.

A propane tank must have an empty zone at the top or it will squirt out liquid instead of vapor and may explode in hot weather

 

[SCUBAInstr]

Here is the deal on SCUBA and SCBA contents....

Pure oxygen becomes toxic to humans when breathed a little past about 20 feet underwater. I hear a lot of folks saying things like "How long can you stay down with that OXYGEN tank?"...etc. Unless you are a VERY technical diver doing very dangerous mixed gas decompression dives, that tank has AIR (like you are breathing right now), or possibly what is called "Enriched Air - aka "Nitrox" in it. The latter requires a little more education that your average SCUBA Diver tho.
(Nifty fact - the air you are breathing right now starts to become toxic at around 218 ft deep)


SCUBA Tanks come in various sizes, made from both steel and aluminum, and can hold from 6 to 150 cubic feet of compressed AIR, and hold from 2000 to 4500 psi. It is a function of Tank Size and PSI that determines how many cubic feet of air the tank can hold.

In the US, SCUBA Tanks must be, according to the DOT, hydro statically tested every 5 years. A failure makes the tank unusable. In the self-regulated SCUBA Industry, most places that fill SCUBA Tanks (Dive Shops) require annual visual inspection of the interior of the tank - and a sticker on the exterior with the date of the inspection. Since any tank with 2000+ psi inside is a 50-100 lb grenade, I am not sure why welding talks are not subject to this regulation as well...especially ones with pure O2 in them....(Hydro test that is)

Your welding tanks will have markings on the neck area telling the Manufacturer, working pressure, material tank is made of, and hydro test dates. If you see "3AA", the tank is steel, and "3AL" means it is aluminum. This sets how much the tank will hold, not the clerk at the welding supply place ;-)

Hope this helps someone...
Tommy D.
PADI MSDT 53405

 

[Owen Aaland]

(quoted from post at 00:45:14 12/24/14)

ust a couple of reasons not to go to a tractor forum for info on propane, or oxygen for that matter.

"[b:c8c0766b21][u:c8c0766b21]A propane tank that has a water capacity of 20 gallons is full of propane with 16 gallons[/u:c8c0766b21][/b:c8c0766b21]."

" The reason LP bottles are only filled to 16-17 lb is the OPD fill valves and the law.
"
FACTS:
The B-B-Q 20# tanks are 80% full with 20# of propane. They are 62% full with 16#. OPD does not stop the tank from receiving 20#, regardless of what the check out clerk at Lowes & Home Depot tells you. Why does Blue Rhino & the exchange places only put 16# in them? Profit & what people will pay for convenience. It is pretty simple, folks.
Don't believe all the 'stuff' you hear.[/quote]

What is not correct with what I posted? I said nothing about weight but rather volume which is how larger tanks are rated. The specification plate will list the volume by the amount of water the tank will hold when 100% filled. The maximum amount of propane to fill the tank will be 80% of the water capacity.