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Deaeration devices for Hydraulic Oil

Deaeration devices for Hydraulic Oil

Deaeration devices for Hydraulic Oil

hi people,

i would like to know what is available to deaerate the hydraulic oil in the tank.

We want to remove air bubbles.

In the past we have seen centrifugal type devices (but I can not find any info now) or special deflector and meshes to built in the tank to remove air bubles,....

Anyone that could provide more info on commercial or homemade devices?

Thanks in advance,


RE: Deaeration devices for Hydraulic Oil

Check with Parker Hannifin. I know thy have these devices. Any local hydraulic company should be able to help you, too.

RE: Deaeration devices for Hydraulic Oil

I have seen centrifugal forces used on dry sump race engines. The reservoir is designed as an upright cylinder with a conical bottom. The return flow enters so that it spins around the perimeter of the reservoir, which helps get the air out.

Check out the Moroso web page for a picture.


RE: Deaeration devices for Hydraulic Oil

Where are the air bubbles coming from?  Make sure your oil returns are all below the oil level, that will help minimize entrainment.

RE: Deaeration devices for Hydraulic Oil


A few years ago we had a Voith hydraulic coupling running at about 2500 HP and 3000 rpm output, 3300 rpm input, (300 rpm slip).  The coupling was used in a helicopter regenerative test cell testing engines and transmissions.  Oil is pumped into the coupling at maybe 400 gpm, taken out of the coupling with a scoop tube whch regulates the "centrifugal ring of oil.  With the oil coming out of the scoop tube is a lot of air. Then the oil is returned to the reservior and oil cooler.  Initially, we had a big problem with oil coming back to the tank with large quantities of air, foaming the tank.

We increased the size and number of vents to the tank. Our solution was to introduce the oil onto a sloping stainless plate which was arranged across the resivoir (above the liquid level) and that was only partially effective.  When we added stainless steel expanded metal laying in the sloping return oil, on top of the sloping plate and the problem went away.  We think the reason that it worked was that the expanded metal caused the laminar oil movement to "flip over" bringing the air bubbles to the surface.

The best thing you can do if possible is to try to identify the source of the foaming and try to remove the problem before it gets to the tank.  In the above example we could not figure out how to change the nature of the scoop tube.  

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