Wood waste grinder

[Kansas]

The plan is this summer to put a new building that will house our operation. When we do this, I want to put in a wood waste grinder.  We haven't settled on the exact floor plan yet, but I suspect it will have both bandmills, the resaw, gang edger, and pop up saw along one side. We run most of the first cuts through the gang edger and cut them into cants for the resaw. If we can get a 1/2 x 3 1/2 inch board 34 inches long out of a cant, we take it. As such, most of the material thats left is fairly small. This building will be fully enclosed.  How do other operations set up something like this? I have wondered about putting in a conveyor belt to feed a wood grinder. Some feed from the top, some are horizontal. I want a grinder that makes a nice mulch. The cresswood and some others that are lower speed and lower horsepower look intriguing. Any ideas or experience with this?

[Ron Wenrich]

When it comes to woodwaste, you don't want to handle it any more than necessary.  You can run it on belt or vibrating conveyors.  If you're handling lots of small material, chains won't work too well. 

Are you going to mix the sawdust with the other waste?  If so, then you can run everything on one conveyor.  If you're going to separate it, you can run it on a one conveyor, but will need some way of pulling out the dust.  You can use a grate on a vibrating conveyor to do this. 

When guys were grinding wood for mulch, they usually put in a wood hog.  These were more like a shredder, and could take some pretty big chunks.  A horizontal feed gives you the luxury of putting in an unlimited length.  Top feeds means you have to have sufficient drop to handle your longest piece.  There's an arc that has to be engineered in to accommodate the drop.

From my standpoint, I always look at how quickly and easily something can be cleared when it jams up.  Since you won't have a hog attendant (no offense pigman), what happens when a vertical feed gets filled up as opposed to a horizontal feed?  A lot depends on the material being hogged.

Brand and type depends on how much waste you plan to shred and if expansion is in the stars.  There are a lot of different makes and models to fit your needs.  I'd look at a lot of them before I decided on one particular company or model.  You're the one that has to work with it. 

[Kansas]

I never thought about a screen to allow the sawdust to fall through. I think it would make a better mulch if we did. I did buy a blower big enough at a sawmill auction a few years ago to hook up the mills and resaw and planer.
I may go that route for those, but the gang edger has too many chunks of wood coming off of that to hook it up to that. I do think horizontal is the way for  us to go. We cut too many 16-20 ft trailer deck orders for a vertical grinder.
I think a road trip is in order to look at some other operations on their layout, get some ideas.
Thanks for the advice.

[backwoods sawyer]

One of the cleanest operations that I have seen had the sawmill on the second floor with three vibrator conveyors underneath. The sawmill was set up in a rectangle with the primary breakdown along one long wall, a transfer, unscrambler and scanner along the short wall, this fed the three edger's that were set up along the other long wall. All the edger's dumped onto a transfer chain along other short wall that that went to the sorter and trays then out the door at the stacker. The infeed and out feed of the mill were side by side.
The chip system had one conveyer under the headrig and another under all of the edger's both of these conveyors ran parallel to each other. There was a 6' section in both conveyors that that had a series of 3" holes to allow the fines to drop down to second layer of the conveyor. At one end, a third conveyor had a trough along the side of it for the fines. The tailings went thru a Nicholson chipper, then to the surge bin, a screen, and finally to the sort bins.

[Puffergas]

I worked in a large furniture manufacturing plant and they use vibrating conveyors feeding hammer mills. This was a horizontal set up. Worked pretty good.


Jeff 

[Cedarman]

We use a horizontal grinder with 100 HP motor.  Mulch is blown into a truck. When truck is full, it is switched out with another.  Sometimes the company can't get here for a few hours and we have to buffer the waste.  We can fill the truck in 2 to 3 days with our waste stream.
We put all slabs , edging strips,cut offs and sawdust through the hog. Will only take slabs 5" and thinner. Sawdust does not hurt our mulch.  We also sell by weight.  If selling by yard, you will get nothing for the sawdust as it settles between the larger pieces.  We sell by weight because there is not a good way to measure the actual yards of mulch in the truck.  We have done this for 10 years or so.

We have a belt that runs full length of mill and feeds a vibrating conveyor. It would be good to put an amp measuring device on the hog to shut down the vibrating conveyor  if the hog starts to overload or out put gets clogged.  It is not too hard to clear the clog.

Kansas, do lots of research on hogs. I would use a different one than what we have.

[Brucer]

The cedar mill and pole mill down the road from me have a different approach. They pile up all their slabs, butts, rejects, etc. in one huge pile -- about 16' high, 30' wide, and as long as it has to be. Then once or twice a year they hire a guy to bring in a portable grinder.

I haven't seen "under the hood", so I don't know what does the actual grinding. It has a 6' wide horizontal steel conveyor about 16' long and it's got a pair of 650 HP Cat diesels driving it. Apparently the guy hauls it around to various operations that don't want to invest in their own system.

Someone told me it was there last week, so I might just mosey on down with the camera tomorrow if time permits.

[Kansas]

Brucer  That is what we have done in the past.We have an open front to the south and all slash gets pitched outside and then pushed up every few days into a pile. Problem is, the guy that was wholesaling the mulch and arranged for the the grinder seemed to lose his markets when the housing downturn hit. That coupled with all the rain and snow we have had the last two years has resulted in a real mess trying to push it down to the pile. To put it mildly, our yard is a disaster.
Cedarman, I like the idea of using two trailers. If one of these biofuel companies steps up and pays a decent price, I would like to do just that. I am just getting started researching grinders. The plan is to have this all in place in the October/November time frame, so I have some time to try and get it right.

[Ron Wenrich]

We have several trailers for chips and sawdust.  We simply switch trailers with a yard truck when they get full.  Then they can be hauled when the truckers get around to it.