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.

 

[J_J]

As far as return hose, to make it simple, just match up the work port size to filter port size and tank port size. If it makes you feel more secure, jump up the work port output size another 1/4 in, and that will relieve any stress on machine and the man.

Put a 3000 psi gage on the In port , and the a 500 psi hyd gage on Tank/Out port, and you can see the results.

 

[250quality]

Both gauges are on now just need to complete the return where both 3/4 lines tee into the 1-1/4. I am running a 15gmp gear pump and it worked before with a 3/4 return but trying to improve the system a little thats all. If nothing else it will make me feel better.
Still need to make the return connection at the rad but may think about by-passing it if it would be better to go straight to the filter. Just have to keep an eye on the temp gauge for a while.

 

[temsan]

Pressure Relief valve.