Circular Sawmill Blower Size?

[doucetteowen]

Hey guys, I have a circular sawmill for sawing lobster trap material. We have a 38" blade that we run at 1000 rpm but are thinking on buying a 42-44" eventually, and a lathe saw that runs up to three 10" blades. Its all powered by a 240hp CAT diesel. We want to install one sawdust blower to handle both saws, belt driven off the main saw shaft.  I was just wondering what size of a blower we would need? HP is not a factor as we have lots of it. And we are probably looking to buy a new one. thanks!

[thecfarm]

Welcome to the forum.
Lobster traps out of wood? I thought those was all metal now.

[doucetteowen]

Thanks! Im from Prince Edward Island, and almost everyone here uses wood traps still.

[thecfarm]

Don't get to that part of the country much.  ;D  Guess I should.

[irvi00]

I'm using a 26 inch 4 blade blower with a 15 hp three phase motor. It overkill for my bandsaw and edger. But I bought it for a song and it does a great job.

[dgdrls]

Welcome to the FF doucetteowen,
I cant help with the blower question but
how about posting some photos of your mill and
some of those traps??

best
D

[doucetteowen]

[dgdrls]

That is a very neat set-up,  do you build traps as well?

Best
D

[dustyhat]

 Medium size blower , i would contact  ( Pendu Manufacturing ).

[Don P]

can't help you with how big but just a little physics. Diameter makes the pressure, width makes the volume the fan will produce. A big narrow wheel makes a lot of pressure but few cfm's where a small diameter, wide wheel moves a lot of air at low pressure.
On my mill I built my own fan, there is a real basic calc I made for that in the red toolbox on the left of the page. I have a 13" dia x ~4" wide radial fan that is about the minimum for that single, relatively short run.

Run belts and pulleys if possible so you can play with rpm's to tune it but beyond a point speed is just noise. I was chopping and rewelding an old industrial air handler that was direct drive and wish I could play with rpm's.

Adjusting the cutoff point, the narrowest point between the case and wheel greatly affects efficiency but also noise

[longtime lurker]

First thing is to figure out where you're going to pipe it to. Lot of difference between piping it twenty foot up then 300 foot horizontally, and piping it five feet up then a 100 foot downhill run.

From that and projected volume and chip size you can size your pipes.

From your pipe size, number of bends, fall etc etc you can calculate resistance.

Only then - once you know volume, chip size and static resistance - will you know the minimum volume of air and pressure you need to generate.

Then double it, because there's nothing worse then having to unblock clogged pipes more then once a year.

[bandmiller2]

Owen, I just measured a sawdust blower I have around, about 14" fan. As you know circular mill sawdust is a misnomer actually it is small chunks. The fan needs to be tough as knots pebbles and who knows what else ends up passing through. If you make the fan you would be wise to use 1/4" steel. Would be easiest to run it with an electric motor and belts to tweak the RPM's. With the electric motor you can clean up without the large hungry diesel running. Companies like Grizzly make blowers but they are targeted towards tablesaws and fine sawdust. Do you use white oak for your pots.?? Frank C.

[Kbeitz]

I see big blowers coming in to the junkyard all the time.
Looks like something I should be gathering up.
I never thought about it before.

[Don P]

These are a special kind of blower and would be worth pulling out. Most blowers are squirrel cage type air handlers with many small backward inclined fins. A material handler is a radial fan with just a few large heavy blades that run from the hub straight out, radially, to the rim. Well meaning friends have dropped off several large air handlers here. I did cut the squirrel cage fins off of the heavy hub on one and welded on radial blades and narrowed the case to make my sawdust blower.

[doucetteowen]

Thanks for all the advice guys! I contacted Pendu and am waiting for a reply, their blowers look nice and rugged, like they could handle the large "sawdust" of the circular saw. Yes we cut all our trap lumber and build our own traps, its a family run mill with 6 family members using it ( cousins and uncles). We usually use juniper for posts and lathes, and rock maple for the palins and sills (the larger peices). As far as all the calculations for piping and resistance, im not entirely sure on how to do those

[Kbeitz]

Yesterday I was at the junkyard and seen this... It looks tough...



 



 

[Don P]

I don't know, the impeller is different than I've seen for sawdust. Was it for liquids?

This is a link to info on sizing and designing a dust collection system;
http://billpentz.com/woodworking/cyclone/index.cfm#index.cfm

[Kbeitz]

I don't know, the impeller is different than I've seen for sawdust. Was it for liquids?

This is a link to info on sizing and designing a dust collection system;
http://billpentz.com/woodworking/cyclone/index.cfm#index.cfm

I thought that at first but the back side has no liquid tight seal.
So It has to be for dry goods.

[loganworks2]

In my wood shop I use a old blower out of a machine for insulation.  It works great on the 12" planer for the shavings. I blow them about 150 ft into a pile. It looks a lot like your find kbiets only about half the size.

[Kbeitz]

This think weights a few hundred pounds. I did not take it...
I have all I need.

[SineWave]

I did not take it...
I have all I need.

That's just crazy talk!

[Kbeitz]

I did not take it...
I have all I need.

That's just crazy talk!

There is no way I could take all the good stuff that comes into this junkyard...
Good engines every day.



 



 

Tractor parts..



 

Tools...



 

Stuff come in faster than I can look through it and if your not there when it comes
in it's gone the next day.



 

[tmbrcruiser]

Check out Meadows Mills, I purchased a blower from them. The fan is heavy metal and all parts are replaceable.