Drag Conveyor HP

[macmet]

I am trying to size a drag conveyor to carry hogged wood. I have used two sources of information; the first one is an FMC catalogue and the second is a Martin Sprocket and Gear catalogue.

The FMC catalogue has a fairly good step-by-step approach. With this method I get ~ 7HP, which is just below the range I expected to get. The FMC catalogue is literally older than I am and I would feel more comfortable with my result if I could back it up through another method.

The MSG "method" seems to be a bit of a shortcut. It basically gives me an HP/ft rating based on the conveyor width and material density. When I use this method I get ~33HP. The density of the material in my application is less than half of the constant MSG assumes.

I tried google as well and came across a brochure that used a method similar to MSG. Again the assumed density is much higher than mine.

So, I searched engtips and came across,

http://eng-tips.com/viewthread.cfm?qid=189881

That thread directs the OP to an SEW manual which I cannot find. Does anyone have access to this manual or know a url where I can find it?

I'm also curious what other approaches people use to size chain conveyors. Can anyone recommend another good source for this type of information?

Cheers.

 

[Ross0684]

Hi Macmet
Try a search for Renold Chains (UK company).
I had a quick look and there is some information in pdf on their site, but can only assume that is it similar to their printed catalogues(my copy is 1970)-the information still applies-gives you friction factors etc for sliding materials, timber etc.
plus Step by step instructions for drive calculations.

My rule of thumb is:
total loads (lbs) x speed (feet per minute)x friction (30% for timber sliding on steel-horizontal)/33000=HP
HP=TL x fpm x n%/33000

I have not seen an FMC book in years but would think it would not differ much from Renolds
Good luck
Ross

 

[diskullman]

Even better try going to Rexnord's website. I would have originally suggested Falk gear drives, but apparently Rexnord owns Falk now. You should rely on the gearbox manufacturer'r specs, as they will be the ones to cover the warranty on the heart of the drive.

I relied heavily upon Falk in the past, as we'd say "Falk Gears, Falk Couplings, Falk Everything!"

Russell Giuliano

 

[macmet]

Well thanks for the help.

I actually have an old Rexnord book and an old Falk book. I'll go through them tomorrow.

I also went to the Rexnord site and found some information that seems a little bit current than what I have sitting on my desk now.

Thanks again.

 

[Ross0684]

Hi Macmet
Out of general interest, give us some feedback on your solution when you finish ie loads and speeds etc.
One never stops learning!!
Ross

 

[PeterCharles]

Why the fascination with catalogues? Chain conveyors are simple things so work from first principles, it's only simple friction after all.

Chain pull is a function of mass conveyed and coefficient of friction. The only trick is what coefficient of friction to use, but that can be established by very simple tests, the simplest being just an angle of slide test. If all else fails use a value of 0.5 as a start point.

Once you've got chain pull then multiply it by speed and you've got power. Include some efficiencies for the drive components, stick on the next size up motor and you're done.

 

[macmet]

I went through and compared the results of a few different sources. Basically the results I got were all within a horsepower or two. Some are higher when there is no incline and others are higher when there is incline.

Basically, other than the MSG quick formula, my results are all similar. I've picked out a drive to use and I will post back with my results once the system is up and running in the fall.