Blowing Shavings into a Trailer
Tips on modifying your dust collection system to convey wood waste to a large trailer. June 15, 2014
Question (WOODWEB Member) :
I need to find a source to get rid of my planer shavings. I'm at the point that I need to add a transfer fan below the airlock and start blowing into a 50' trailer, but don't know where to locate a source for an outfit that provides that service. I'm in the Metro Detroit area. Any help in locating a source or pointing me in the right direction would be appreciated.
Forum Responses
(Dust Collection and Safety Equipment Forum)
From Contributor M:
What lumber species are you using? Is it all clean KD lumber? You should be able to sell your shavings to local dairy or horse farms (no walnut for horses) or someone making wood pellets or briquettes. You can also look into briquetting yourself. There are also sawdust burning furnaces you could heat your facility with. Check yellow pages and online for sawdust guys. If you don't make it fast enough, they may charge you trailer rental.
From Contributor T:
Setting up a closed loop transfer system is fairly simple. You will need to have an adaptor plate made to attach to the bottom of your airlock to attach a tee. Finding the right fan can be a challenge. I suggest purchasing a used Murphy-Rodgers MRT system (perhaps a MRT-12 depending on the distance from the airlock to the trailer) - they are readily available and fairly inexpensive. From the discharge side of the tee run your piping to the trailer. From the trailer run a line back to the fan that is at least an inch larger in diameter than the supply side. From the outlet of the fan run a line back to the tee. There are a few dust collection installers in MI that can help you with this if you don't want to do it yourself.
From Contributor M:
Closed loop will keep the mess down. Make sure you have a large enough fan to get the chips to hit the front of the trailer. A larger line pulling air out will prevent a wall of air midway in the trailer keeping it from the front. Also look into a vibrating wand sensors to let you know when the trailer is almost full. It’s good to have one positioned a few inches below the return outlet in the trailer door as a warning, and another even with the return wired to shut down the system so you don’t fill up your cyclone.
From the original questioner:
To answer a few more questions, my shavings are primarily maple and when I do plane walnut I've always kept it segregated because I have had horse people coming by and picking up my shavings for me and using it as bedding. The problem is that I have been generating more than they can sometimes handle and it's becoming a hassle trying to always have someone pick them up when I need it. I'm currently dropping from the airlock into two different six yard containers that are on wheels so they can roll them to the edge of the loading dock and transfer the shavings into their trailer. On a busy week they're here sometimes two-three times.
Contributor T - I do have a used Murphy Rodgers that came with the tee for the transfer fan, but not with the fan itself. The control panel is already set up for the transfer fan, so that seems like the easiest solution if the landlord will let me have a trailer spotted next to building to blow into it, but that's not a sure thing either. Because my heat is folded into my rent I don't have any incentive to put in a wood fired furnace to heat with. I've been checking into briquetters, but the cost of one that can keep up with my double surfacer is out of the question. The entry level Weima or Comafar will let me run for maybe 15 minutes before I'll have to give it a break to let it catch up with me. I need to be able run for a half hour at a time, as I tend to run things in batches. So with all that said, you can see the dilemma I'm in.
From contributor G:
We blow our dust into a metal silo that I bought used for $1000. It is 8' in diameter by 16' high. We do this because our Wiema briquett press can't keep up with the volume of dust while we make it. However it can easily keep up with the volume over the course of a day or two as the planer and moulder run intermittently. The dust is augured out of the silo into the press. We burn our briquetts for heat.
From the original questioner:
To contributor G: That's probably the way I'll end up going. If I can find the right kind of buffer for the briquetter, whether it's a silo or something else, I see the briquetter as the easiest solution, although not the least expensive.
From contributor G:
Keep in mind that sawdust is notorious for bridging. My silo has agitators that run horizontally just above the unloading auger but it still plugs up more than I wish. We used a 1 1/2" holesaw to cut holes in the tapered bottom of the silo to stick a piece of rebar in to break the bridge. There are better solutions for this problem but for the money I can live with mine.
From the original questioner:
I'm very aware of bridging. I found myself wondering about bridging in your silo arrangement. I currently drop from the airlock into a large container on wheels and if I don't keep an eye on the level of the shavings going into the container I'll bridge above the airlock and then back up into the baghouse. I really need to install a monitor camera looking at the airlock so I don't let it get too full.
From Contributor M:
You can also place the vibrating wands above the airlock to warn/shut down if sawdust is building above the airlock. I have heard about using a trailer with a moving floor to feed the briquetting machine. Blow in to fill it as usual, then use the moving floor to unload into the briqutette feed. I’m not sure if this is a viable alternative to the silo but it gets around bridging.
