Using compressed air through a venturi pump to suck oil?

[kdv1988]

Hello, was wondering if I could pass compressed air through a venturi pump to pull floating oil from a tank? If yes, how do I control the eventual mixing of oil with the air from the outlet end?

The requirement is given to me by one of my clients who wants an easy, and low-cost solution to remove 'tramp' oil from their CNC machine coolant tanks. I've drawn a quick sketch to explain the application. Can this work? I am assuming the oil will mix with the air inside the venturi to form a kind of mist?

Any advice would be great. Thanks.

 

[Jboggs]

Contact Exair. They have a large variety of venturi based products including wet-dry vacs. I've always had good experience with them. They aren't afraid of specials if needed. Talk to one of their application engineers. They have probably done this exact job before.

 

[LittleInch]

was wondering if I could pass compressed air through a venturi pump to pull floating oil from a tank?
Yes

If yes, how do I control the eventual mixing of oil with the air from the outlet end?
You can't. That's why not many people do it this way.

Can this work?
Yes - See above

I am assuming the oil will mix with the air inside the venturi to form a kind of mist?
correct.

If I was you I would either use water and then separate it out again or just buy an air driven pump....

Or just buy a skimmer pipe like everyone else does. See link and scroll down a bit. Other people do floating devices.

https://www.skimoil.com/slotted-pipe-skimmer---c-pipe-skimmer.html

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[kdv1988]

@LittleInch
Thanks for your response.

I cannot use water since that will need another tank to store the water & recovered 'oil+coolant' coming out of the venturi.. thereby defeating the purpose of having a small and perhaps portable solution.

Can those Oil coalescing cartridge filters work if fitted downstream from the venturi?

 

[3DDave]

Seems like a fine way to build a fuel-air bomb or a flame thrower.

If you put an intermediate, vacuum tight barrel that had a vacuum drawn on it by the venturi and then had a hose that fed down to the bottom of the barrel so that the velocity of the oil was spent in stirring of the collected liquid with a ball-float cut-off to the venturi, that would be much safer. One could mount the float and hose fittings to the barrel lid so that when one barrel filled, the lid could be replaced with another and the float and fittings be moved to an empty barrel to restart.

 

[TheTick]

Sounds like you're making a carburetor. Carburetor's purpose is generating an explosive fuel-air mixture.

 

[LittleInch]

Actually that's what you need to do:

Plug the vacuum line from your eductor into the top of a small tank fitted with a float chamber and then run a line to the bottom of the small tank / vessel able to with stand some level of vacuum and use that to hose off the oil.

J Boggs is right Exair do something similar...

https://www.directindustry.com/prod/exair-corporation/product-17836-2099651.html

Or use an AODD pump?

Or

https://www.vac-u-max.com/vacView.cfm?cat=air-operated-vacuums

Coalescing cartridges are designed for fine oil mist, not huge globs of it. Basically trying to extract the oil out of the air is the wrong way. Don't get it in the air stream in the first place... IMHO.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Strong]

Compressed air is expensive. Have you considered a skimmer that is made for this purpose?

https://www.bing.com/search?q=remov...7j69i64.12238j0j1&pglt=43&FORM=ANNTA1&PC=U531

Walt

 

[LittleInch]

Looks pretty "easy and low cost to me...."

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[BrianPetersen]

Dealing with CNC coolant is not a new problem. Companies build equipment to do it, and there's a reason they do it the way they do it.

 

[TugboatEng]

Here is a "tramp" oil skimmer.

https://www.mscdirect.com/browse/tn...6rL1O4lhJcxOANenhehoCR7QQAvD_BwE&gclsrc=aw.ds