Eductor causing Foaming in my tank (system drawing attached)

[kdv1988]

Hi guys, facing a bit of a problem here. Please see the system layout here :

https://imgur.com/a/6d4XWxj#nZbOKG1

I've connected an eductor to the coolant pump in my machine. This eductor sucks the leaked cutting fluid from a tray underneath the machine I.e coolant passes through the venturi(let's call it motive) and returns to the tank and in this process a vacuum is developed which is used to suck up the oil from the tray which travels with the motive and enters my tank.

Now the problem I'm facing here is once all the leakage oil has been sucked up the device keeps sucking air which is then effectively injected into the coolant sump thereby causing a lot of foam. How can I prevent air from entering the tank? I cannot use any timers or solenoids to turn off the system. Need a simple mechanical suggestion please. Currently the pipe is inserted into the coolant to ensure it does not spray coolant all over the place. Will clamping this pipe above the coolant level help?

 

[kdv1988]

How do I know the foaming is caused by the Eductor? Well I have given a ball valve just before the Eductor and the eductor is on a bypass line. So when the valve is closed, there is no fluid going through the eductor thereby the suction of fluid from the tray stops and so does the foaming.

 

[LittleInch]

Haven't you answered your own question?

Just turn it off when you don't need it to suck anything up.

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

 

[DAVIDSTECKER]

Look for some sort of "Float Valve" that will shut of when the level drops to a certain point.
When the level rises, then the valve opens and lets the fluid get sucked out.

 

[btrueblood]

Don't use an eductor, use a pump.

if you can't for some reason use a pump, you might have success locating the output line above the liquid level and using a coalescing filter (multi-wrap screen) to separate the coolant from the air stream...which should work for awhile. Dimethicone in the coolant tank might also knock down the foam.