PTO driven fan/blower: Looking for ideas

[RonMar]

I have used the 48" mower deck on my riding mower to "accelerate" burn piles. It works real well, but you have to have the discharge fairly close so the riding mower is a little too close to the fire for comfort. I never thought of building a duct for it, that would probably work good. I have also used a leaf blower, even at idle it really gets things going.

In playing with the leaf blower, I found a little bit of air goes a long way. I made up a small rig I use to get brush piles going hot. It consists of a piece of 4" thinwall steel duct about 4' long and a 12V box fan from radio shack. I power this with a 12V 6AH gellcell battery out of an old UPS. A fully charged battery will run this thing 12+ hours. I push a lit oily rag into the base of the pile with a stick and stuff the end of the pipe into the pile right behind the rag. It roars like a blowtorch and quickly builds a pile of coals to get the burn pile really going at the center. I am contemplating making a slightly larger version using a automotive squirrel cage heater blower and a small car battery. I came up with the electric as I didn't really want an engine running alongside the pile all day. This is quiet and really cooks down the piles quickly.

I try not to burn too big of piles as I don't want them to be going and me keeping tabs on them till all hours of the night. Since I have the same problem as described, really old slash piles with a lot of dirt as well as the damp northwest climate. I reform them into smaller looser piles with a fork bucket that gets most of the dirt out and leaves plenty of passages for air. The small electric blower is pretty much fire and forget and I have the tractor free for other work and to scoop the outlying material up and onto the superheated core.

Be carefull breaking down those larger piles. I have come across bee hives in my older piles.

 

[Highbeam]

Ah, beehives. Yet another reason to be doing this work in the early spring. I have hit some mouse/mole/shrew nests already. Those little buggers can move fast.

I am finding that a lot of the junk in the piles can be shredded up with the brush hog since it has rotted a good bit. I am hauling the stumps to a dedicated stump pile so the monster slash pile is more of a bulk sorting operation than a burn.

I'll have to try idling down the leaf blower to half way. The leaf blower on full blast consumes a good bit of gasoline and the noise is high at max rpm. Big fires mixed with big air from a big fan would make an impressive amount of heat. Ductwork or a very directional airstream of some sort would be required for the burn stage. The start stage wouldn't require a duct.

The logger also told me of a trick they used to use where they set up a diesel drip tube to drip fuel into the airstream of their firefans for maximum fire starting heat. Maybe a little dangerous and enironmentally risky but what good things aren't?

 

[srjones]

Everyone,
Thank you ALL for the input..this is great!!! I think I've come to the conclusion that the simplest solution is usually the best so I'll probably go with a centrifugal fan. I'll post some pics when I build it.

I agree that for burning stump piles, a steady stream of air is best to keep it burning. I actually have a 2nd tractor that will be perfect for this task -- an old Mitsu R1500, single cylinder diesel @ about 8HP.

Speaking of bee's, I'm also a beekeeper, and yet another use of a blower is to 'forcibly evict' the bees when it comes time to harvest the honey by blowing high volumes of air through the honey supers.

-Steve

 

[ns_in_tex]

Here is a link to one I made from an old belt drive finish mower deck.

 

[jimmysisson]

ns, that must be one huge pulley in the housing - like 16" diameter or something? What do you think the fan turns at? I like your belt tensioner with the spring. Does this rig shake very much at speed? Do you use it for a leaf blower or what?
Thanks, Jim

 

[rdbrumfield]

If you want to get serious about moving air, go down to the local airport and see if you can come up with a usable prop. Sometimes they have to be scraped for one reason or onother, but some can be shortened and usable for ground operations such as our needs. By making an arbor and caging the blade the rotation is right for making some big wind.

 

[rdbrumfield]

At Ft Benning, USAR Jump school, I remember being dragged across the field by a parachute that was being blown by a pickup that was modified. It had a ford 352 V8 turning a 6ft prop with the drive shaft direct instead of going to the rear differential. You sure learned how to unsnap the risers quick to keep from filling your back pockets with rocks.

 

[oliver28472]

My brother made one out of an old silo blower like jimgerken referred to. Talk about air, he uses it on a 485 Case IH to blow leaves, burn brush etc. He has the outlet turned around so that it comes out horizontally on the bottom. If there are or were any dairy farms with silos in your area you can pick those up pretty cheap, then you will have to fab up a 3 point hitch. The tubes are usefull to get your tractor a safe distance from the burn pile.

 

[Taylortractornut]

Highbeam any place that does indoor painting Glueing ore fiberglassing should have a few. THa have about a 2 foot turbine type cast 5 bladed airfoil prop thats perfec and the suction side has is 2 or 3 foot openng and the fan and then the back is tapered down a foot. Lots of furniture catoried havee them. Ive got an extra with a bad prop. Its got 2 inches of the blade off one end. If I cant get another cheaply Im gonna make a templae of the break and trim all the others off a bit. and balance it on the tire stored old wheel balancer. Your welcomed to it if you want it I got it from a plant I worked for that shut down as part of a clean up. THey come in alot of sizes I thing with 3 HP at 1700 rpm its 1500 CFM output.

 

[Highbeam]

Well it's not worth the shipping and effort but thanks anyway. I like the old furnace blower squirrel cage idea from a safety standpoint. I'll have to look into the cfms for that and try and scrounge one up at an HVAC shop. I've got an old lawn mower that is dying but the engine is still tops.