Return line size

[250quality]

I was given some advice to up size the return lines on my processor to 1-1/4.
I just finished putting on 2 new valves, a 3 spool with power beyond and an auto cycle downstream from that. Both valves have 3/4 ports on the return side as well as my cooler where they will run to.
Does it make sense to upsize the return to 1-1/4 anyway and if so can I use regular black iron plumbing fittings for the return as there should be little pressure there and it would save me a bunch of trips to my hydraulic supplier.
Thanks
Brian

 

[KYErik]

Black iron is good up to at least 3-400psi so using it on a return line will be fine.

Several years ago, I even used some isolated black iron bushings and 3/8 elbows for a low pressure (1000psi) hydraulic system and had no issues with it- though I know it was a risky application (I placed them in locations so that I would be shielded if they failed).

That said- if the return port is only 3/4 inch- I don't see the benefit in going up to 1.25 inch- unless the return line has lots of twists and turns which would slow flow significantly.

 

[J_J]

Could use some 1 in hose for flex, and pipe for the rest of the return, How about the return filter, is it 1 in ?

 

[250quality]

No its 3/4 as well.

 

[oldnslo]

What flow rate are you operating at?

What will the surge flows flows be and for what time duration will they last?

How long of lines will there be?

3/4" schedule 40 black pipe is rated 16.5 GPM at 10 feet/second

1" schedule 40 is rated at 27 GPM at 10 feet/second

Roy

 

[250quality]

What should the return pressure be or will it vary per system?

 

[J_J]

If the fluid is flowing through a return filter and it is new or clean, there should be very little pressure on the return/tank port. You could put a low pressure gage on the filter and monitor if concerned.

 

[Discount Hydraulic Hose]

Black iron is good up to at least 3-400psi so using it on a return line will be fine.

I can't speak for all black iron, but we sell some malleable black iron fittings on our site, and these fittings have a pressure rating of only 150 PSI.

Black Malleable Iron Pipe Fittings > DiscountHydraulicHose.com

I would definitely check the rating for any black iron pipe and fittings you are using before assuming that they will handle 300 or 400 psi.

 

[oldnslo]

What should the return pressure be or will it vary per system?

It will vary with each system. I presume you are using a gear pump on your wood processor so there will be continuous flow in the return line. I would try to have less than 50 PSI measured at your valve tank port.

Roy

 

[triptester]

Check your filter base many have a built-in bypass valve which opens at 15 psi.