A portable Venturi Vac system?

kdv1988 · Jun 23, 2021

Hello,
We make a Venturi vacuum system for recovering CNC coolant from the swarf trolley. It is a simple arrangement consisting of a venturi tube tee'd off the coolant pump and a stand-off placed at the bottom of the swarf trolley with a filter disc.

Now the problem with this system is that it is dedicated to each machine, where pressurized coolant passes through the venturi from the pump (motive) and creates a suction through which coolant is sucked from the swarf trolley. Coolant that passes through the venturi is returned to the sump. A schematic is attached for reference.

Now, I have had multiple clients ask for a similar portable system. But I can't for the life of me figure out how! I could use compressed air or even a Turbine Blower to generate the vacuum in the venturi, but the sucked coolant will mix with this air on the outlet of the venturi. How do I avoid this?

Thanks,
KV

LittleInch · Jun 23, 2021

I don't think you can.

You can create a low pressure from the air line which you could maybe use in a piston to "suck" the coolant up, but this wouldn't work on a continuous basis like the liquid driven model. Or it connects to the top of a vessel and you have a demister pad and float to stop the liquid from entering the chamber.

You could use air to drive a liquid motor in a closed loop and then use an venturi

Or you drive the air and entrained liquid into a coalescer, but they tend to be quite big.

Or just buy a wet and dry vacuum like this.

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3DDave · Jul 4, 2021

I'm interested that the venturi creates a vacuum that is strong enough to draw the coolant all the way up from the swarf tray through the filter disk but then is not strong enough to draw it back up the tube that leads to the coolant tank.

How does the coolant escape from the highest vacuum location?

I could understand if it was a reciprocating pump with check valves, but veturis are usually for a continuous process where which check valves will not work.

Decap · Jul 6, 2021

If the idea is to recover coolant from the chip tray of one machine and put that recovered coolant back, then it seems like to me you could mount this system on a cart, use an air motor or electric motor attached to a coolant pump with a flexible inlet / outlet line, both in the coolant sump of the machine, to generate some coolant flow through the venturi loop.

If that's not an option then you may be able to do something with a trap on the vacuum line, but I haven't thought that through much.

kdv1988 · Jul 9, 2021

@Decap, first part of your post is exactly what I've done this week.

Took a simple AODD pump and dropped its suction flexible pipe straight into the machine sump, discharge pipe from the pump connected to my Venturi, outlet of which is returned to the sump with another flexible pipe. Took trials and the system works!

Some queries :-
1. Used an AODD pump since no flooded suction can be provided (pump mounted higher than the tank). But this has led to a pulsating flow at the outlet of the venturi that goes back into the sump. Can this be turned into a continuous flow? Pulsation Dampener / Centrifugal pump perhaps?

2. We took this trial with only water. I am worried that the pulsating flow will cause some atomization of the coolant or maybe foaming might happen? Not sure.

Any tips?

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A portable Venturi Vac system?

kdv1988

Mechanical

LittleInch

Petroleum

3DDave

Aerospace

Decap

Mechanical

kdv1988

Mechanical

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