Multiple hydraulic motors

[Toomuch]

What is the consensus on driving hydraulic motors from one source? I have to design a system to drive 5 material screws at approximately 60rpm/3hp. Unfortunately space restrictions do not allow for a single point drive plus the augers have to be moved out of position fairly frequently and I don't believe the group would stand the handling. I am having problems with designing using flow dividers because of the odd number and the wasted energy, a rotary would work but the possibility of pressure intensification if a drive pin would shear has it's drawbacks to. I am almost thinking of individual circuits that would be driven from a gang pump with individual valving. I know the cost aspect but the benefit of being able to drop one screw out of service if a problem arises has its attraction. Or Five individual motor/pump/valve combos is also a possibility. Any other ideas?

 

[MikeHalloran]

Old school solution:
Five gear pumps stacked on one shaft.





Mike Halloran
Pembroke Pines, FL, USA

 

[hydtools]

I'd go with multiple pumps, per Mike. If not five elements on one shaft, then multiple (2+2+1) tandem pumps on multiple drive gear box.

Pressure intensification can be handled with pressure relief valves on the motor side of the gear splitters.

Ted

 

[kcj]

Spool dividers, big energy losses on unbalanced legs, but gear dividers don't have as much energy loss. The energy from the low load section transfers over the the highly loaded sections.

Some rotary dividers (Haldex Barnes for sure, and I think Parker) have relief valves built in to prvent intensification. Each section has a RV cartridge from output to inlet.

That said, I'd go with separate stacked pumps somehow. Less interaction of pressures, espeically if you are trying to control loads or close the loop in some way.

 

[Toomuch]

Thanks to all. I have decided to go with my original idea of stacked pumps (3+2), with valves and 2 individual drive motors. This gives some flexibility in case of a failure or blown hose. I didn't want to go with a rotary flow divider as it adds troubleshooting problems for the maintenance staff and the spool dividers create more heat for the system. the one system that we do have a rotary divider in has the built in reliefs and has had a couple failures in the relief valves (poor system design) so it wasn't at the top of the list. Again thank you for your time.

 

[EngineerTex]

At 3 hp each, why couldn't you run them all in series? Downside being that you would have a slight issue with case drain losing additively more flow across each one. However, you could use moderately larger motors than you had originally planned and it would remove all of the difficulties of troubleshooting you were talking about.

Just make sure that each motor has its case drain going back to tank, instead of downstream.

As for how to run them together, you could integrate a check valve on the downstream side of each motor and put a 2-position, 3-way valve on the pressure side of each motor and connect it to the downstream side of the check valve and voila -- you can turn a knob and pull a motor out of service.

Engineering is not the science behind building. It is the science behind not building.

 

[faqs]

How much do the loads on the motors differ on an average basis. In other words, do the motors run at pretty much the same losd most of the time?

faqs