Design of Venturi

I don't recomend doing this... You will likely be introducing large amounts of contamination into your system, which will eventually kill all your more sensitive components.

You should invest in a small electric motor and cheap gear pump to work as a kidney loop... And BE SURE to filter the oil before introducing it back into the system!

IF (big If) You know for sure that the oil is clean and filtered, this can be done relatively easily and efficiently. Back in the 80's Volvo was doing this for a while with reasonable success... since then I have not seen this done in the USA, but I believe you can find these setups in the UK. Maybe you could dig up Volvo's old design... I think they got bought out by Saur Danfoss, and then someone else may have bought the line, not sure anymore who owns who... I think parker just about owns and shuts down all their competition....

Basic Venturi design can be found all over the internet... just type it into google.

you can use small pump with proper filtration. this is the best option.

Otherwise as per ur idea of ventury-

You can use ventury which is used in dm water plants / softner for suction of regenerating liquid [brine?]. Again you needexisting pump size, flow etc. for proper selection. or use trial method. You can also attach filter to this.

The only place in your circuit you could do this is in the return oil line.

This will add back pressure to the 'tool', reduce the pressure drop across the 'tool' - so lessen the hp available.

It may also induce air into the return oil in the main tank, resulting in air induction in pump suction - so cavitation and associated destruction.

These are the likely reasons the idea remains 'not designed'.

Oil return... or Suction... either one in my opinion is a bad idea... to do it right make a kidney loop with a cheap gear pump/filter.

FYI: I design Hydraulic circuits/systems for a living, and would not use the venturi trick on anything. I always use a kidney loop with good filtration.

FYI ? How could I not know what you do for a living, it's regularly mentioned

Naturally, I'm a little bemused that you mention suction in the context of a scavenging function.

You as well as I. I said it shouldn't be done... but a few companies have done this in the past on the suction... Volvo being one. I'm not saying its a good idea by any means, but it has been done.

I had a little dig on that when you first raised it - got nowhere (in the 5 mins allocated) but can't see it as other than being a piggyback on a pre-pressurising pumps bypass.

I doubt the OP has one.