Use hydraulic motor for very slow rotation, or is there a better way? 2

[minfarm]

Hello,

I have a bin with a unload system in that I am trying to improve. This system has two screw conveyers that go out from the center of the bin. (see photo for more detail) While these screw conveyers are spinning, I would like to power rotate them around the bin.

I have calculated that I will need approximately 400 ft-lb's of torque. The biggest problem that I see is trying to get the rotation slow enough. I only need it to rotate about once every three hours. This would put the horsepower requirements as fractional.

Would it work to use a hydraulic motor, under sufficient pressure to apply the 400 ft-lb's, or would that cause problems because it would be turning so slow? Also, if I did drive it hydraulically some way, what type of pump setup would I need for the very low flow rate?

Any help will be greatly appreciated!

 

[minfarm]

Thanks for the suggestion, but this unload can only be run with clockwise rotation.

 

[berkshire]

Minfarm,
Since you appear to be stuck with what you have, would you consider changing the round ribbon screw conveyors for flat ribbon screw conveyors. you may get a little more grain breakage but I think it would take care of the fines problem because the flat faces would give more draw to the center. Again this is a ribbon conveyor not a full screw.
The other solution may be to throw a couple of Syntron feeders on the bin with the vibration direction towards the center and use them only when the screws stopped feeding. See page 12 of the attached catalog.

B.E.

You are judged not by what you know, but by what you can do.

 

[ScottyUK]

minfarm,

I'm back on a desktop instead of my cell phone so it's a bit easier to post links:

http://www.sumitomodriveeurope.com/en/coaxial-gearboxesgearmotors/cyclo-drive-6000/

Listed for food applications, and reduction ratios available > 7500:1 with enough torque to shift the planet on its axis. I met these as a component of turbine barring gear and they were trouble-free in the ten or so years I was involved.

 

[minfarm]

Thanks again for the help and suggestions.

After considering all the suggestions, I plan to leave the existing screw conveyers in place. I will mount a 50:1 right angle gear reducer in the center of the bin. This reducer will have a drive shaft attached to it that will extend horizontally to the outside of the bin. On the outside of the bin I will drive the shaft with a Sumitomo 1003:1 ratio Cyclodrive gearmotor. The gearmotor will be powered with a variable frequency drive for additional speed control. Operating the motor at 10 hertz should give me about .006 RPM. I will be able to speed it up from there if I need to.