air tank for vacuum

Oct 30, 2019 20 Replies

I need a way to vacuum hot oil without collapsing a vessel. We have been using 55 gallon drums for oil that has cooled down, but, they will collapse when enough hot oil is vacuumed into them. My thought was to use a 20 gallon,



200 psi, 650 degree F rated air tank. This would not be a true vacuum. There will be constant air flow. The hot oil that we need to vacuum is only about 1 to 1 1/2 inches deep, so, a standard hot oil pump will not work.

You can pull a good very high vacuum on a 304ss, 15 gallon beer keg. with no problem. I've done that many times with no problems. They weld easily with TIG.

Weld a skeleton around the drum?

You can pull a serious vacuum on a depleted Freon tank. Also there are refrigerant recovery tanks that have dual valves - one for gas at the top and one for liquid with a dip tube to the bottom.

First thought is put a valve on the vacuum line, if you can't do that can you put an air bleed on the drum to control vacuum?

It would help to know how much oil is being picked up and it's viscosity, both hot and at ambient temp.

HTH,

bob prohaska

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Can a paint pressure tank hold a vacuum?

Yes, the Harbor Freight 2.5 gal paint tank makes a nice vacuum chamber for degassing resins for casting and potting (according to several YouTube videos). As others have said, we really need to know how much oil will be sucked up at one time. I'm also curious how the 55 gal drums failed - did the ends or the side give way and implode?

I killed a 55g, years ago, with my AC vac pump. The sides collapsed on that one.

I'm sure it will vary, but here are some school kids trying it out:

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Are these plastic drums or steel? I think that the vacuum is about the same value for hot or cold oil, but the hot oil softens plastic drums, making it easier for the vacuum to collapse them.

How big a tank? Remember, tanks made for pressure are not necessarily structurally designed for vacuum -- high or even mild. I presume that the level of vacuum is what you get out of a Shop Vac type device. The limit there is what the pump can produce before it starts spinning faster because the air in the device is too thin to resist the motor's force.

Again -- is it a plastic drum? I'll bet a steel one would collapse at the same vacuum whether hot or cold -- and a higher vacuum than what collapses the plastic drum when hot.

Good Luck, DoN.

Robert Roland snipped-for-privacy@ddress.no on Sat, 02 Nov 2019 20:08:58 +0100 typed in rec.crafts.metalworking the following:

The Mythbuster guys managed to collapse a tank car. But they had to "ding" the tank to compromise the structural integrity first. (The first time they tried, they got a vacuum of 27 inches Hg, but no collapse. Third time, they dropped a 3,200 lb concrete block on it, and the tank collapse at 23 inches Hg.)

Yeah, that's the key; a round tank (or even a flat lid atop a can) doesn't spontaneously break symmetry, you have to START that. So, an undented drum should hold vacuum well (it's only 14 psi) just as a beer can should be hard to crush. But, I can hold the beer can and dent the sides with my fingers, then a little twist... and it's flat in seconds.

Half-crumpled 50 gal tanks can be re-formed to original shape, quickly, if you have a blasting cap handy...

whit3rd snipped-for-privacy@gmail.com on Sun, 3 Nov 2019 17:55:12 -0800 (PST) typed in rec.crafts.metalworking the following:

Old "trick" balance on an empty popcan. Then reach down and tap the sides. "Crunch!" as the can collapses.

"a little gasoline, a torch, good as new."

A New England winter gives a rain-filled 55 gallon drum a neatly domed end.

replying to bob prohaska, Leighton1210 wrote: It is 68 weight hydraulic oil. The real issue with it isn't the amount of oil we are trying to vacuum up. The issue is the heat involved along with the length of hose needed to do the job. I apologize for not stating that in the original text. The hose is 15 foot long, 1 inch diameter. The depth of the oil is only around 1 to 1 1/2 inches, but, it covers an area approximately 160 square feet. I would be constantly pulling air along with the oil. Sometimes, though, there is debris that will get vacuumed up. All of these minor items, i believe, causes the issue that I have. I'm just not sure of a good way to do this, other than when the oil is cooled off. As for the valve on the vacuum line, I should be able to put a valve on the vacuum head. I can make it adjustable and see what happens.

replying to bob prohaska, Leighton1210 wrote: It is 68 weight hydraulic oil. The real issue with it isn't the amount of oil we are trying to vacuum up. The issue is the heat involved along with the length of hose needed to do the job. I apologize for not stating that in the original text. The hose is 15 foot long, 1 inch diameter. The depth of the oil is only around 1 to 1 1/2 inches, but, it covers an area approximately 160 square feet. I would be constantly pulling air along with the oil. Sometimes, though, there is debris that will get vacuumed up. All of these minor items, i believe, causes the issue that I have. I'm just not sure of a good way to do this, other than when the oil is cooled off. As for the valve on the vacuum line, I should be able to put a valve on the vacuum head. I can make it adjustable and see what happens.

Where is the oil before it gets spread out like that? Any chance of using gravity to collect it? Or vacuum it out of whatever it came out of?

The water expands as it freezes?

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