big mash rake questions

I am going to start working at a small distillery part time. I toured it today really cool setup with really nice products. The one thing I noticed is that they dough in by hand with a drywall mixer. I am going tommorrow to help them make a batch I will get dimnsions of the mash tun and such from first look it seems to be around 4 bbl capacity. I am going to help them design a mash rake. I looked at the local 7bbl brew pubs rake today and have a basic paddle configuration but have not had any luck finding any info on the HP rating and rpm needed. Would a 1hp motor reduced down to about 20 rpms have enough torque to dough in the mash?

There are many different gear reduction drives that a 1/2 HP will handle at a 100:1 reduction. Boston Gear is one with a double worm reduction, Winsmith, Perfection, Browning, Falk, Hansen and Foote Jones off the top of my head.
The 100:1 Boston Gear I have has an output of 815 in/lbs @ 17.5 rpms, a Winsmith 60:1 @ 29 rpms @ 565 in/lbs as an examples.

BrewBeemer said:

There are many different gear reduction drives that a 1/2 HP will handle at a 100:1 reduction. Boston Gear is one with a double worm reduction, Winsmith, Perfection, Browning, Falk, Hansen and Foote Jones off the top of my head.
The 100:1 Boston Gear I have has an output of 815 in/lbs @ 17.5 rpms, a Winsmith 60:1 @ 29 rpms @ 565 in/lbs as an examples.

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That boston gear looks promising this is new territory for me I am pretty excited to help build this. Are there any specific things I need to look out for when selecting motors and boxes? I have 220 avaible as well

I am going to help them design a mash rake. I looked at the local 7bbl brew pubs rake today and have a basic paddle configuration but have not had any luck finding any info on the HP rating and rpm needed. Would a 1hp motor reduced down to about 20 rpms have enough torque to dough in the mash?

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I am not familiar with brewpups, my answer is based on conventional breweries.
Standard mash rakes are not used for mixing only to cut the grain bed to help during lautering.
You need a mash mixer with 20-40 RPM.
Standard rakes.




Keep in mind the function of the mixer is to mix the grain not just rotating it.
To calculate the impeller power you need the power number for the type of impeller you are using (supplied my manufacturer) or use the standard values.
Mr Google can help.
To do the calculation you need the mixer RPM, fluid specific gravity, mixer plates diameter and power number or experiment.
Currently I am looking for my old info, I am very rusty on this subject..

My 200 liter mash mixer with adjustable blade angle and supported on both ends.




146 lb-in, 26 RPM motor



Cheers,
ClaudiusB

jppostKW said:

That boston gear looks promising this is new territory for me I am pretty excited to help build this. Are there any specific things I need to look out for when selecting motors and boxes? I have 220 avaible as well

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You would need to know the in/lb load the mixing arms will require at the rpm's you want then work backwards matching the proper size gearbox for the load plus the proper angle of the box and motor HP. This meaning a parallel drive in/out or a 90 degree drive. You must keep in mind these larger gear reducers require the vent cap to be at the top of the box as they are oil filled.
You'll have sticker shock as they are not cheap with most having a motor frame mounting bell at the end. My Windsmith box is a 90 degree shaft drive in/out, the Perfection Gear has a Baldor motor as a single unit with 90 degree out. The best part you have 240 volts available for a low/high voltage motor wiring.
I see Claudius B is using only a 146 in/lb TQ motor for his mixer, that's only 12 ft/lbs as a comparison to his blade length and width that works for his system.

Thanks claudius I think I was a bit mixed up the brewery I looked at had the lautering rakes like you showed with the random design paddles in their lauter tun in the kettle there was a big propeller looking thing supported on the ends like in your 200 liter pic. Hmm I guess I will see what they do tommorrow. If the dough in is where they have issues that will be pretty simple the torque rating and rpm are pretty easy to find.