Oxygen Cylinders for Transfill

[M20F-1968]

What are people using for Oxygen refill and transfill of onboard Oxygen tank?  I am considering purchasing two "T" tanks (but may purchase a total of four given that the shipping is the same for 2 or 4.  They are tanks that have only been used to store medical oxygen.  They will have new valves (#540 - not medical valves), be newly hydrtested and pained medical green.  If any one is interested in one or two of the tanks, we could share shipping.  I can be reached at (617) 877-0025 or emailed at johnabreda@yahoo.com   Does anyone have a better idea that to own tanks for transfill?  I know they can be rented but over the years, it seems that it is better to own.

 

John Breda

[N601RX]

It used to be that 4 or 5 years of rental was about the same as a purchase.  I purchased my Oxygen tank as sell as a Argon and CO2 tank that I use with my welder many years ago. I got them from the local welding gas supplier.

[MB65E]

I believe PraxAir charges $35-40/ month for the T size bottles. Then they exchange when it's empty. I'll look up the cost of the refill... Probably not what your looking for but helps if you don't want to haul O2 bottles around.

-Matt

[larryb]

I purchased my tanks from the local gas supplier. They are used, but it doesn't matter because when you really get a tank swap when you bring it in for a fill. So you exchange one used tank for another. The gas supplier is responsible for hydro testing, etc.I looked into buying my own shiny new tanks, but when I checked with the gas supplier it seems they just like to exchange empty for full tanks and they don't like to fill your personal tank. I use 2 125 cu-ft tanks because they are light enough to move around and get into the back of my SUV by myself. 250 cu-ft tanks would probably have been more cost-effective, but too hard to handle due to weight.

 

Larry

[chrisk]

I rent two large tanks.  I want to say it was $5 per month per bottle, but I would have to go back and find the paper work.  When I need a new bottle, it is just an exchange, which is very fast. And I don't have to deal with a periodic hydro-static test.

 

Also, the tanks are really heavy.  I can barely move one by my self.  If I ever knock one over I'm going to have a really hard time picking it back up!  I think they are around 300 cubic ft.

[M20F-1968]

I am trying to fill a 50 cubic ft bottle in my aircraft.  What size bottle would I need for transfill?  Is 125 cubic Ft large enough to fill my aircraft.  It would seem that a 125 cubic ft bottle, starting at bout 2500 in pressure would equilibrate to about 1200 in pressure, which would only be 1/2 of my capacity.

 

John Breda

[1964-M20E]

I would get two of the largest cylinders you can handle.  Use the first one to start filling the empty then switch to the second one to bring up the pressure as high as you can.  Eventually the second cylinder becomes the first one you used and you get the other refilled.  If you are using a really large quantity you might consider more cylinders.

[N201MKTurbo]

I take my cylinder to the gas plant to get filled. They don't mind filling my tank. If you take it to a welding shop, they have to deal with shipping it to the gas plant and back.

[DonMuncy]

Do you know the price differential between the gas plant and the welding supply store. I assume the cost of sending the tank to the gas plant would be calculated into the price.

I'm not sure where to find a gas plant and the welding supply guys are all over.

[N201MKTurbo]

Around here it is the same price. The welding shops and the gas plant are US AirWeld.

 

https://www.google.com/maps/@33.4232124,-111.9954835,3a,90y,106.11h,91.39t/data=!3m4!1e1!3m2!1sGtjDJBwFTXtBqRQyzTKJSw!2e0?hl=en

 

It cost about $20 to fill my big tank.

[DonMuncy]

Another question. Do they fill your cylinder or swap an empty for a full. If they fill yours, eventually (and I admit it is a long time) there would be an additional charge.

I finally ran my acetylene tank out and took it in for a refill. They looked at the tank and found it had been last inspected in 1967. (I don't use a whole lot of acetylene). I had to pay an additional $22 for an inspection. They said the inspection interval was 15 years. I wonder if the guy who happens to have the cylinder when the time runs out is stuck with the charge. My suspicion is that if it is only shortly out of date, they absorb the inspection fee.

[kortopates]

I prefer and would recommend the K sized tanks. The K size holds 200 or 220 or 250 cu ft depending on pressure. Their corresponding Pressures are 1800, 2015 and 2265 psi. Our inboard tank pressure max is 1800 psi. They weigh 105-115 lbs which is quite heavy. If you go with the larger T size which is a 300 cu ft, they have a filled pressure of 2400 psi which puts you at risk of over filling your onboard tank plus they weigh in at 135 lbs.

I bought 2 tanks from my local gas supplier years ago which enables me to go to in and exchange the tank for a filled one. I am also not limited to the original supplier that I got my tanks from and can get them exchanged at other gas suppliers.

Sent from my iPhone using Tapatalk

[chrisk]

The O2 tanks are filled anywhere from 2,000 to 3,000 PSI (200 atmospheres) and are EXTREMELY dangerous if one to be knocked over and if the valve ever broke off. They become uncontrolled destructive missiles  that can blast through cement brick walls, demolish pickup trucks and have killed people.  All this is to say that you MUST store oxygen tanks against a wall with a security chain anchoring them.  They should never be allowed to be knocked over.    Mine is tied up  with two chains top and bottom...Just sayin'.....

 

Phil mc

 

By far, the biggest danger from a falling tank is a broken foot.  Having said that, you are correct that oxygen tanks are indeed dangerous.  Not only are they like a scuba tank where they can burst or shoot off like a missile.  The O2 is a hazard and can burn almost anything.  --And for the record, my tanks are secured.  But there is always the risk of knocking one over when moving one for replacement.

[Tom]

What are people using for Oxygen refill and transfill of onboard Oxygen tank?  I am considering purchasing two "T" tanks (but may purchase a total of four given that the shipping is the same for 2 or 4.  They are tanks that have only been used to store medical oxygen.  They will have new valves (#540 - not medical valves), be newly hydrtested and pained medical green.  If any one is interested in one or two of the tanks, we could share shipping.  I can be reached at (617) 877-0025 or emailed at johnabreda@yahoo.com   Does anyone have a better idea that to own tanks for transfill?  I know they can be rented but over the years, it seems that it is better to own.

 

John Breda

 

Hi John,

Have you looked into the concentrators recently?  How often do you go above 18k?  How many passengers typically?  If typically solo or 1 passenger then a concentrator or two would seem best with an E tank "borrowed" from work with cannulas as an emergency backup to the concentrators.  If using tanks, I'd buy a large welding cylinder off ebay and refill the smaller E tanks in the hangar.  Otherwise why not just borrow-rotate E cylinders from work?

[N201MKTurbo]

I have them fill my tank. If I show up when they are filling oxygen they will fill it on the spot. If not I may have to leave it overnight. I don't let hem fill it from their cascade. Because there is a slight chance the cascade is contaminated.

I have to arrange to get it hydro tested. It costs about $25 every five years. The cylinder shop is two blocks away from the gas plant. I'll drop it off at he cylinder shop, pick it up the next day and drop it off at the gas plant.

[cliffy]

O2 filling tips:

Refill cylinders very slowly. Too fast and they get hot and you will get a false pressure reading. When cooled the pressure can go down several hundred pounds in the filled tank.

Have O2 dedicated tools (wrenches, screwdrivers, etc) and clean them very well with soap and water to remove all traces of any oils or greases from them. Grease or oil in the presence of O2 can spontaneously ignite.

It should go without saying (but I've seen it) NEVER LUBRICATE ANYTHING DEALING WITH O2 WITH ANY PETROLEUM PRODUCT!

I hope you have a pressure gauge on the "filling" tank that can be monitored while filling to avoid over filling if you use tanks higher than 2000 psi to fill with. 

Be safe out there  You can save a lot of money but do it right. 

[Larry]

FWIW, I bought 3 tanks from different people on Craigslist for $30-$40 ea..  The tanks were all customer owned and the 200CF+ size.  If you go this route, there is a steel ring below the valve that will be blank or say "Customer Owned".  If it has the name of a gas supplier, it is leased and isn't worth purchasing.  You don't have to worry about hydro testing since they will normally just exchange tanks.