Can someone help me figure out how much torque I need

1. Feb 13, 2015

Rodrigrows Org

Hello Im new to site and need some help building a big mixer similar to picture the problem i have run into is i need to know what size motor and gear reducer box i need for this application i need to find out how much torque it takes to spin the paddle wheel when fully loaded the the weight of my material is 10,500 lbs my paddle is 5 ft in diameter 14 feet long and I need this to spin at 15-20 rpm can anyone help me with equation for this thanks. http://www.robinrents.com/stow-paddles.jpg [Broken]

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2. Feb 13, 2015

CWatters

Is there anything similar you can compare it with? Such as a concrete mixer? Otherwise I suspect you might have to make a series of smaller prototypes to scale, measure the torque and power required and extrapolate.

3. Feb 13, 2015

billy_joule

With mixing being such a key process in industry I'd guess there's been considerable research done, have you checked unit operation text books?

4. Feb 13, 2015

CWatters

There must be a lot of variables.. viscosity, size and shape of the paddle, clearance between paddle and container..

http://en.wikipedia.org/wiki/Mixing_(process_engineering [Broken])

It goes on to reference the "North American Mixing Forum sponsored Handbook of Industrial Mixing".

Last edited by a moderator: May 7, 2017
5. Feb 13, 2015

MullaTheMech

And 2.5ft instead of the 7ft i wrote

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6. Feb 14, 2015

Rodrigrows Org

Yes your picture is exactly what im trying to build.

7. Feb 14, 2015

Rodrigrows Org

yes i have the problem is no one make a mixer in the size Im making its either much smaller or much bigger.

8. Feb 14, 2015

MullaTheMech

I am a complete newbie who makes tons of mistakes. someone check my work!

at a 1:1 gear ratio you need a motor with a1137 watt output or 50,000ft*lbs
at a 1:2 ratio you need 567 watts or 25000ft*lbs
I don't know how to incorporate the rpm in this formula.

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9. Feb 14, 2015