LOX users - input about this please

[FiredDesires]

This is my "newest?" LOX tank, 2 wks old..it has never vented, pressure never moves..every morning I wake up to this iceberg on top, and now there's this puddle at bottom of tank everyday too. Torching has no effect...now tank is almost empty after 5 torching sessions.

I've called my supplier and he will be calling his...I'm thoroughly disgusted about this tank as it cost me 500.00 a pop and a wait time of 7-10 days for arrival. Everything is barged up here and its' usually a crap shoot on what your going to get. Over the last 3yrs I've had maybe 5 decent runs with this..

So what I'm looking from you experts is verbage to relay to the supplier. I think this is the worst faulty tank I've ever received and it needs to be retired into a graveyard of some sort. Your thoughts please..

[colonel4bin]

Have you made sure the pressure build isn't on? (dumb ?, Right?) Any good supplier should no there is no way you used that entire tank that quickly.

[brettodie]

loks like a leak up around the top seal probably just needs a refurb. is all. they should comp you a tank. a single person would be hard pressed to use that much o2 in just over a week. i worked ina shop with several people a few years ago and wed have to get a fresh tank every thurs. or friday. peace brett

[FiredDesires]

Garrett, no that isn't a dumb remark! I appreciate advice/help, thats why I came here. There's not many folks here in town that know much about LOX, so I'm kind of flying blind here. I switched to LOX 3 yrs. ago upon hearing that they equal approximately 16 greenies, at the price of 80.00 per greenie? I can lose about a third of a LOX and still be money ahead...but not the whole dang tank! lol

I've read on here about backing out a screw slightly in the bell housing unit, is that what your talking about?..hubby gets tank, hooks it up and I torch. I don't fool with knobs and such as I'm quite fearful about monkeying with anything.

I'm used to the pressure always venting off when it reaches 350, if I haven't torched enough to keep it down, and some frosting after a long torch session, but nothing like you see in the picture.

Point me in the right direction about this please, if I myself am not doing something right, then I'll eat the mistake, but even with my minimal knowledge about these after 3yrs, my mind set is that this IS a faulty tank or I've just been coasting along and being oblivious as to operator error on a continuing basis! (sure hope it is thought number 1, lol)

[Emmett's Glass]

That dosen't seem right you should get more time per tank. The presure builder is 1 of the knobs located at the top of the tank usuall labled as presure builder, make sure it's not stuck open. You do shut you tank off in the end of a workday, not just at the torch?
Don't let theses guys do the refurb on the tank. http://www.elcosh.org/en/document/607/d000585/liquid-oxygen-cylinder-explosion.html
E

[FiredDesires]

Brett, you responded as I was typing the lengthy reply above..thanks for your thoughts. This thing is dripping liquid from every pipe/valve that you can see, that is not covered with ice.

It is a older tank from the last one I went through, which I made last 7 weeks! I just don't know enough about them to locate/fix the problems..I'm a scare-dee kat! but I do know I'm getting fed up with losing more than I'm gaining!

[FiredDesires]

Emmett, I definitely agree with you on that one. These tanks come out of Seattle to my supplier here in Sitka..my Sitka supplier is awesome and will go to bat for me over this..by the time these Seattle guys load it on the barge, I wait 10 days, they're pretty much out of the loop and I sometimes think they're thinking they'll just ship anything and we'll be happy about it..10 days up, 5-6wks torch time, 10 days ship back? well its' out of their hair attitude is getting old.

[Emmett's Glass]

Seattle is notorious for giving folks light LOX.
E

[p.j.]

it looks like the tank is venting, maybe you are not hearing it though. it looks like the liquid keeps mixing with the atmosphere, creating more gas than you are using.

the screw on the bell(right off the pressure building knob, which is usually the opposite side from where your gas use is) is the economizer, this controls the flow of liquid into the chamber, where it mixes with the atmosphere you create the gas. try to back out the screw a half turn. then check the pressure building knob and make sure it is shut, i have had tanks that the seal is bad and they mix and blow off i less than a week.

you should call your distributor to tell them your situation, but try the other stuff that everyone has said to try to remedy the problem, until you can get a new dewar

[n3rd]

it looks like the tank is venting, maybe you are not hearing it though. it looks like the liquid keeps mixing with the atmosphere, creating more gas than you are using.

the screw on the bell(right off the pressure building knob, which is usually the opposite side from where your gas use is) is the economizer, this controls the flow of liquid into the chamber, where it mixes with the atmosphere you create the gas. try to back out the screw a half turn. then check the pressure building knob and make sure it is shut, i have had tanks that the seal is bad and they mix and blow off i less than a week.


this is great advice, you need to be aware of the pressure builder AND the economizer.

[Greymatter Glass]

The economizer bypasses the main pressure builder valve, and is a cryogenic regulator in effect. It sets the "head" or gas pressure of the tank. When the tank pressure goes below the economizer setting it will let a small amount of liquid into the pressure building coils. If it's set to a higher head pressure than the relief valve you'll always be venting.

What you have looks more like a leak in the manifold somewhere, probably where the level gauge comes through. But it could also be a very small crack in one of the feed lines. Make sure the pressure builder knob is fully closed, but otherwise looks like you have a bunk tank.

Personally I wouldn't accept a rusted tank that's got ice on it at delivery... that's a very clear sign it's FUBAR. I'd find a better supplier if this happens often.

The liquid you see coming out of the ports, is it water condensing on the cold pipes or actual liquid O2? You can tell if it's the later because it will steam and boil off anything it touches.

The water at the base of the tank is just melt from the ice ball up top.

Also, considering where you're at and the wait time for tanks it might be worth getting a 1000# capacity scale and putting the tank on it. The tanks will always have a tare weight on them, and liquid O2 weighs a few ounces over 402 lbs for a 160L fill (2.515 lbs per liter). From that you set the scale to what a full tank should weigh, verify it's full and then set the scale to about 30# over the tare weight. When the scale arm drops it means you're about out of oxygen, time to order more.

-Doug

[Tunnel Pig]

Wow, that sux

I can't tell from the thread though, is this your personal tank? Or is it a rental? If it's your's then of course get a refurb from someone that has a good rep.

If it's a rental and you're in an area that your tank is being filled in Seattle, then barged, then trucked, and whatever else this thing has to go through to get to you. If there is any problem with any part of the bell valve, pressure builder, seals, etc... Let's say it's a bad tank, sitting on a barge and venting off 3/4 or more of the tank till it's at a level that the tank doesn't vent anymore?

The verbage you need to use with your supplier is you are paying a premium (5-10 times retail price in a major metro area) That you require they pay attention to which tank is yours. These guys know which tanks are crap and are in need of a major overhaul when they fill them. Tell them to find a tank in good shape and mark it with a big old sticker saying " I AM GOING OUT ON THE OCEAN AND WILL BE SUBJECT TO ROGUE WAVES AND MAJOR SHUFFFLING AROUND."

It's good you have a good relationship with your supplier, it's time for them to step it up.

Maybe that'll help. Good luck!

[puddletown]

Have you considered getting a oxy concentrator? $500 a fill?? sounds like a pretty steep price. have you tried to figure out the cost difference between the two options?

[FiredDesires]

Everyone...thank you for your ideas and super information. I do not own the tank, it is rented from Seattle. My supplier here orders them from Seattle for me, I don't fault him one bit..

puddletown, 500.00 is fill and rental combined..as I said earlier, at $80 per greenie times the number that is equal to this price of the lox..I'm still money ahead..but only if I get more than 5 dang torching sessions. Also, what concentrator do you know that will run a CC+, Barracuda or the Phantom? I have 3 concentrators for making beads.

PJ..in the top right picture, directly behind the bell valve with the little screw in the end...that turn knob right behind it? is that the knob your speaking of that needs to be completely shut & all the time?

My son, who runs the CC+ just came over today and looked at the tank, there is a small crack in one of the metal tubes around the other side, and finally today, after two weeks the ice has disappeared. Tank is reading empty now.

You guys have been really great and thanks bunches for your input. I'll print this out for future reference, plus I'm giving a copy of this thread and the pictures for my supplier to send back to Seattle with the dud, er, I meant tank!

[p.j.]

PJ..in the top right picture, directly behind the bell valve with the little screw in the end...that turn knob right behind it? is that the knob your speaking of that needs to be completely shut & all the time?

!

yes, and that little screw is the economizer, good luck!!

[Snurf]

Dam 500 a tank is pricey. I would get pedals for everyone in the shop. Then use Green tanks in the summer, and liquid in the winter. You could even hook up concentrators for the centerfires(when running of of the Green tanks).

With how cold it must be in the winter up there, I'll bet liquid would last longer, and vent less.

[Greymatter Glass]

With how cold it must be in the winter up there, I'll bet liquid would last longer, and vent less.

At nearly -300°F inside the tank the external tank temperature has very little effect on the liquid inside. Unless you can get the external temps down below -294 the oxygen is going to boil off at a pretty steady rate.

In theory the less energy going into the liquid the slower the pressure would build, and I am sure there's some math to show that every degree change would equate to some volume/time change in the system, but in practical terms.... naw, you won't see much change.

Of course with a bad tank with no insulation left, then yeah... but we'd have to assume a sound tank for the bet to be fair anyways.

[Greymatter Glass]

Dam 500 a tank is pricey....use Green tanks in the summer

$500 is a lot of money, more than anyone in the lower 48 pays, but its still very cost effective vs. high pressure cylinders.
Oxygen is Oxygen.

A 160L dewar ($500) holds ~24 220cf tanks.

24 * $80 = $1920

So liquid is about 1/4 of the price as high pressure tanks.

Why would you ever use high pressure tanks? You can vent 3/4 of the liquid and still come out equal.

-Doug

[FiredDesires]

Once again, more informative input from our great members here.

Yes, Doug..I stated earlier about still being ahead money wise at losing/venting much of the LOX compared to greenies..but for years here? I wasn't aware that the LOX was an option for me and can't tell you how many greenies I've burned up before switching over. And you say that the 160's are equal to 24 greenies? In my past research I found 16 as a figure, course I like yours better!
As for the liquid puddles and drips off of, what seems like every dang connection..it doesn't do that little steam look you speak of, but when feeling the liquid with my fingers..it doesn't feel like straight water..but a silky feeling texture.

PJ...thanks for the clarification..I understand it waayyyy better now. I did go out and recheck the pressure building knob and it WAS completely shut.

Snurfy...that is a good idea you have there and it could happen with my set ups.
My husband has been after me to chuck it all and buy a generating system, greenies and do my own refilling...how sweet that would be...when I hit the lotto and have several thousand to throw at somebody..that could be a reality.

I did ask my supplier to price out the bigger dewar...2000K, er..I think I'll stay with size I've been getting.

So glad I came here to talk with all of you..your information has been stellar, and I don't feel so intimidated by these LOX tanks as I did before..a cautious & healthy respect still prevails...but I'm less of a skeerdy-kat! You all are the bomb...

Since hubby is up north right now on a moose hunt, it is left up to me to load this puppy into the truck and haul it out to the welding man...now where did I put that key to the fork-lift...lol
(it will be worth the effort, hubby called yesterday from the tundra and said to put some grease in the frying pan... he killed a bull yesterday morning with a 50" spread on the rack, whoohoooo, meat in the freezer for the coming year)

May all your torches sing a lovely song..and the muses are well awake and on your shoulders.
hugs,
Catharine

[fyrsmith]

Thanks everyone for the good info. Maybe I should look into LOX here in Kodiak.

[The Cheese]

Little bit of an aged thread but...

I keep getting leaky tanks - two from the vent, tap it a few times and it might quit for a little bit and on another the gas use valve leaked. So 3 for 3 lox tanks have been shitty. You'd think that given the nature of their business that there would be tighter regulations and better upkeep. They make the kids at McDonalds take better care of their fry baskets than these idiots here take care of their high pressure equipment.

It's gotten to the point that they won't sell me ANY gas anymore. Have to switch up suppliers this week. They said that I must be doing something to the tanks trying to get some free air. Fuckers... Yeah, I'm going to take a nail to the valves and tinker a bit. I'll have a cig going and everything.

I've dealt with lots of types of different wholesalers. I've worked in construction, maintenance, restaurants, etc... One thing I've noticed, in every type of industry, is that about 3/4 of them are just merely arrogant assholes. The other 1/4 will screw you with a smile and a handshake. So getting a leaky tank that they charge by the volume for isn't surprising.

Too bad you get screwed that bad on your tanks up in the way up there. You'd think at that price they'd at least send you a decent tank.

[J Howard]

at those prices, i'd seriously consider getting a really big compressor and make your own oxy generator with a storage system (aka big holding tank).

i looked into it once, and decided it wasn't worth the money, but i get my tanks for like 120$, not 500