OT Vacuum Bottle

Looking for but not sure the technical name of the intermediated water bubbler bottle that goes between the vacuum pump and the bell jar that will clean the stuff that may appear in the bell jar as being evacuated so as not to contaminate the vacuum pump.

Got links would be helpful

Thank you.

Reply to
OGY
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Scrubber?

Reply to
Arie de Muynck

Are you sure that a water bubbler is what you want? If you draw down to a reasonable vacuum, the water will boil (without heating). My guess(tm) is that you're looking for a vacuum filter, trap, drier or scrubber which removes water and other contaminants from the air sucked out of the bell jar before they can wreck your vacuum pump. This article gives an overview of available filters: Also, if you have large amounts of water involved, you may need a refrigerated condenser to get rid of the water.

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Jeff Liebermann     jeffl@cruzio.com 
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Reply to
Jeff Liebermann

I still cannot find a bubbler.

I am sucking the air out of epoxy or molding compound and similar.

I have seen them at a factory. Just a large bottle with water in the bottom. One long pipe into the water and one short pipe.

Are these custom or commercially available ?

Jeff Liebermann wrote:

Reply to
OGY

If Google can't find it, it doesn't exist. (Liebermann's Law)

No problem. I've done that for epoxy potting compound. All we had was a inlet filter. No water.

Which factory? What were they making? Can you contact them and ask?

I'll try one more time. If you draw down more the 30 mbar absolute pressure (where atmospheric pressure equals the vapor pressure), the water will boil at room temperature. Plug 30 mbara into the calculator below and notice that the calculated temperature is room temperature: If you don't believe me, just evacuate a bottle with some water in it and watch it boil. Or, watch a few YouTube videos demonstrating how water boils in a vacuum at room temperature: In other words, an inlet bubbler is not going to work.

I have no idea. Maybe if you disclose what manner of "epoxy or molding compound" you're using, I could lookup the required vacuum? If it's not much of a vacuum, you might be able to use water without having it boil. Search for "vacuum inlet or intake filter" and you might find something: Extra credit for disclosing the maker and model number of the pump you're using so the flow rate (and size) of the filter can be calculated or estimated.

I have an Edwards E2M1 two stage vacuum pump with plastic intake filter: On Pg 29 of the service manual: You'll find a drawing showing 8 different inlet filter types.

Also, you might want to look into resin degassing equipment such as:

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Jeff Liebermann     jeffl@cruzio.com 
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Reply to
Jeff Liebermann

High vacuum does strange things to water. At work I have seen a 6 inch diameter pipe that is in about 100 deg F area and steam traced with a

1/4 inch pipe and insulated form a ball of ice and clog the pipe. The device making the vacuum was a hollow tube with steam blowing into it through a hole about 1/8 of an inch in diameter. There are seveal of thease in series to make the vacuum.
Reply to
Ralph Mowery

Yep. Put a bubbler in the vacuum intake and it will also produce ice.

"It's Scientifically Possible to Boil Water Until It Freezes Solid" If you watch the video, notice at the beginning, the effort put into preventing water vapor from enter the vacuum pump.

The water boils when the vapor pressure equals atmospheric pressure. If the vacuum is lowered to less than this point, the water starts to evaporate, taking the higher energy water molecules with it, which is also the residual heat in the water. Eventually, all the "hot" water molecules end up in the water vapor, the water temperature drops to freezing, and remaining low energy water molecules form ice crystals.

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Jeff Liebermann     jeffl@cruzio.com 
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Reply to
Jeff Liebermann

You've so much more patience than me. When they ignore my advice the

1st time, they don't deserve any more help.
Reply to
Bob Engelhardt

Being cheap, I use an old pressure cooker as a vacuum chamber. That and a vacuum pump I acquired surplus from Hughes Aircraft.

The only problem I've had is the "safe time" before materials start to cook off. I've used it with silicon, Tru-Cast resins and Epoxies.

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Reply to
Fox's Mercantile

Well, I have a rather different approach. I spend far too much time answering questions on Usenet, mailing lists, and forums. I try to be helpful, but in most cases, it's more for my personal benefit than for any benefit to the person asking the question.

In order to produce a useful answer, I first needed to do some research. I already knew that sucking water into a vacuum pump was a really bad idea, but I didn't really understand why or what alternatives were available. Some Goggling and fast reading provided the necessary details, which I provided in my reply. While my answer was probably beneficial to the person asking the question, it was equally beneficial to me by adding yet another item of trivial knowledge to my vast collection.

Reading between the lines, it would seem that the person asking the question does not understand what happens in a vacuum. He seems to be lacking in experience at asking questions on Usenet or in forums. Tracing his IP address shows him on Road Runner Cable somewhere in southern California. He's using: User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:49.0) Gecko/20100101 Firefox/49.0 SeaMonkey/2.46 which seems rather old. I'm not sure what's happening there, but offhand, it looks like an older machine and operating system. The style of his question seems to be rather jumbled, terse, lacking in technical terms, but where all the words are correctly spelled. That suggests a smartphone user, using speed to text software. By the sentence structure and apparent frustration, I would guess a fairly young person, possibly a teenager.

So, after reading my analysis and guesswork, do you still think that they don't deserve any more help?

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Jeff Liebermann     jeffl@cruzio.com 
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Reply to
Jeff Liebermann

On 7/6/2019 1:31 PM, Jeff Liebermann wrote: ...

First I'd like to say that I appreciate the effort that you put into your replies, even when I'm not the OP. You have a great deal of credibility and when there's a long thread that has sidetracks of the "Yes it is" "No it isn't" variety I often skip most of it and read your replies.

But, to the point here: your 1st reply brought up the boiling-under-vacuum problem. Which he totally ignored in his reply to you and repeated his original request for finding the device he thought he needed. If they're not going to listen, I'm not going to waste my time. If he won't listen, he probably can't be helped anyhow.

Reply to
Bob Engelhardt

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