Screw Pump

[Palmetto Coast]

I am looking for a good eccentric screw pump (aka Positive Displacement screw pump or progressive cavity pump) to move molasses. Anyone have any good leads or good results using another type of pump with molasses?

Thanks,

Todd

[Beauport Bob]

Todd, Will molasses be diluted? Will it be heated? If not you will need a big diameter hose to get the product through. I'm sure you cosidered using gravity. As you have seen, it is the most reliable for us.

[Dave Weglarz]

Beauport Bob,

I plan to move molasses that is both diluted and heated (slightly, not cooked, but to help with dilution). What sort of pump would you recommend for that? And would it necessarily need to be different than the pump I'll use for moving my grain mash? (which I'm still trying to decide upon... recommendations there would also be greatly appreciated. I'll be utilizing corn, wheat, rye, and barley in my mashes and plan on using a hammer mill to grind it fine so as to optimize starch conversion and then distill on the grains, so the mash will have some particulate)

Thanks in advance for any help you can give me!

Dave

[Bier Distillery]

Would a cavity/screw pump with a 3/4" in/out be able to move a 2 lb to 1 gallon ground/flour grain mash?

[Artisan Still Design]

something like this would work good.(picture randomly taken from the internet)

[Silk City Distillers]

If you've got the room, probably cheaper to buy a fork lift.

[Bier Distillery]

Aye, there's the rub. No room for the forklift to get where it needs to go.

[Natrat]

If a progressive cavity lobe pump (pictured above) or screw pump is too expensive, a larger flexible impeller pump will work great, and handle viscosities of 25 000, 40 000, or even 100 000 centipoise (molasses is usually around 20 000)

GW Kent has a good Jabsco with VFD and remote, but it's $5k

[Bier Distillery]

I guess what I'm wondering is how much effect the inlet/outlet size has on the pump's ability to handle grain in mashes. The one I've seen in use was 3". Is 3/4" far too small?

[Natrat]

1.5 " minimum, 2" is great. 3" is overkill, IMHO. Three quarters may stick...and is a pain to clean out.

[Silk City Distillers]

2 pounds per gallon based on flour-ground solids would be relatively easy for an air-powered diaphragm pump.

[Bier Distillery]

That I do have (pneumatic diaphragm) but it's 1/2" npt in/out. Again I wonder if it's too small.

[Silk City Distillers]

Problem with the smaller diaphragm pumps is their ability to pass solids shrinks to almost nothing, and the flow rates leave a bit to be desired.

My 1/2" ARO can handle about 1/16th OK. I've tried pumping a fermented grain-in mash, just for kicks, and it worked, but it's abysmally slow with my smaller compressor, and the hoses were convulsing with every pulse. Honestly, it would have been faster with buckets. Concur with Natrat, something closer to 1.5", with the ability to pass at least 1/4", would be better suited and provide much more flexibility.

[Natrat]

One of the issues with a smaller diaphragm pump when pumping solid-rich slurries is that the cycle is sealed with elastomeric balls, and the particles can keep them from sealing properly, which decreases pump efficiency.

The stainless lobe type pump (such as the one Steven pictured above) is really the best option, if you have the funds. Followed by a progressive cavity screw pump (but they take up a lot of space), impeller (best bang for buck), diaphragm (I have a 2" ARO that rocks, but they surge, and work best when there's a bit of back-pressure), peristaltic (the big ones are pricey), and in a pinch...a big centrifugal (I used to have a 4" Thompson to transfer mash from a mash kettle to lauter tun on a big DME brewhouse...needs priming, though)

Keep your eyes on ebay. I got my big diaphragm for under $1000...