Ideas wanted for moving/blowing sawdust

[Matt_Meiser]

Wood dust explosions are a...well, explosive topic on woodworking forums. Especially metal vs. PVC ductwork. Just like grain dust, flour, etc., wood dust could explode in the right combination of dust, air and an ignition source. An MIT guy has an essay about the possibility and found it extremely remote. You're best off researching and making an informed decision. Personally, I've got PVC ductwork for my dust collection. Other than attracting fine dust to the outside due to static cling, I haven't seen any hint of a problem.

Most sawdust from a woodworking operation is going to be mostly small chips/shavings by volume. The finest dust proves problematic to collect (another explosive topic on the ww forums.)

 

[patrick_g]

Matt, Of course dust explosions are a possibility with most any combustible dust and static electricity could theoretically ignite flamable dust but 1st let me repeat a challenge I was given.

Site evidence that there have actually been wood dust explosions caused by static electricity generated by blowing wood dust through PVC pipe. Sort of took the wind out of my sails too. We talk about tornados as a clear and present danger but at ground zero of tornado alley the frequency of any given residence receiving significant tornadic damage is on the order of once every 4000 years according to the NWS Severe Weather Center, Norman Oklahoma. Yet we see entire neighborhoods wiped out on the TV news.

I have read over and over about cyclone dust collection systems with PVC for ducting being an explosion hazard but have yet to see a real example sited.

A bare wire (attached to a good earth ground) stretched inside the plastic duct will go a long way to eliminating the static buildup. If someone wants to be really really safe they can use metal ducting.

Pat

 

[Matt_Meiser]

Pat, I agree completely--reread my post.

 

[bullridin_fool]

sorry to be off topic but i just wanted to mention that i live in weedsport NY to.

to stay on topic if ya wanted to i could probably give it a look and see if i could come up with any ideas, it's usually a bit easier when you can see the project.

 

[schmism]

any material dust is combustable if in a fine enough partical

dust is considered a class 2 div 1 enviroment. (i used to design explosion proof lighting)

 

[patrick_g]

schmism, I'm sure you meant any normally combustable material. Stuff like salt doesn't combust no matter how fine it is ground, ditto lots of substances. IF it won't oxidize it wont combust/explode.

When I was in the service working around electronic stuff someone decided to order everyone in the training devices section a pair of electrical safety shoes. One of my friends worked on a radar navigator and radar bambardier simulator for the B-52 combat aircrews. As he worked around really high voltages he was happy to get electrical safety shoes.

I have always been a read the label kind of guy and when I saw the "green cross" safety label I read it. There were instructions for how to periodically test the shoes during storage prior to issue that gave me a BIG CLUE and the suggested uses of the shoes scared me. I hollered at my buddy to stay away from the high volts and threw my box of shoes at the guy who ordered them. The suggested uses were in mines, grain elevators, spray painting and other operationis where static electricity could set off an explosion.

These electrical safety shoes were made to ground you out to prevent static sparks not insulate you from electrocutioni!

Pat

 

[patrick_g]

I haven't seen any hint of a problem.

Oh, I got it the first time Matt and agree with you however:

The first hint of a problem might well be when the ducting violently explodes and throws jagged shards of PVC all through the shop and occupants. I agree it isn't too likely.

Having my new house hit by a tornado isn't too likely either but the master suite is made of ICF with 8 inches of steel reinforced concrete and I am building interior steel plate storm shutters.

As I have some left over HD spiral wrap metal ducting from the HVAC work, I may as well use it for my dust collection system when I get a chance to install it.

On a related topic (sort of) Lots of folks use plastic pipe for shop air but if it were accidently smacked it could toss some jagged chunks violently. Although copper is probably the RIGHT way, plain iron pipe with proper filters is ceratinly safe and good enough. Don't waste $ on galvanized the zink is only on the outside and you can just paint the outside or ignore it.

Pat

 

[Soundguy]

Are you thinking sawdust or wood shavings? Dust would be bad for the horses lungs. Shavings is a bit of a different to handle than dust.

Around here, 'saw dust' is more like kitty litter to food pellet sizes chipped wood.. not fines like conventional saw dust.

In any case.. our bulk suppliers all load with a loader, and use a dump truck to deliver.. and generally dump in a stock pile or stock box that can be covered.. then trips tot he horse stalls are made via wheel barrow, or FEL.

I really doubt a vacume cleaner will be of much use besides cleaning the shop..

Soundguy

 

[tcarter1]

Since I am in the dust collection equipment business, I'll chime in here with a few thoughts.
1. If you are going to move the material into your barn pneumatically, you should use a cyclone as a receiver. The material can then fall into a wheelbarrow, drum, or whatever collection device you desire. The cyclone will also separate the larger particles (good stuff) from the really fine dust (bad stuff).
2. Shop vacs. will not get enough work done for the trouble.
3. DO NOT USE PVC.
4. Overall, I would recommend you stay away from an air system altogether. Way too many opportunities for a fire or explosion.

 

[weedsportpete]

My apologies to everyone for not responding sooner - I've been off my feet for two days with a stomach bug. I did get some seat time in yesterday, so my wife is suspicious that I'm getting better.

Health and safety does come before convenience, so we are concerned about the foot problems and explosions.

Renze - Right now, with wood pellet bedding, we have no foot problems, and over the last few years, the few cases ( two or three) have all been related to activity outdoors, so I sure do not want to introduce a new contributor to health problems. I will consult with the CHO (chief horse officer) on this subject. I'd like to think that careful, daily stall cleaning will avoid this.

tommu56 - Thank you - I looked at their web page and it seems focused on metal, or at least rigid, ducting. If we get sawdust delivered, and it is merely dumped, we ( I mean me) will have to fork it up into the (to be built) sawdust hopper. If we go with a gravity fed system, then the hopper will extend several feet into the air, and thats more lifting work. If it is not gravity fed, that is - if I have a blower system - then I have more leeway to build the hopper into a lower, but wider profile.

Pooh Bear - This sounds encouraging (and I see others have said the same thing about choosing a smooth interior surface). I guess a lot of this depends on how far I'm moving the sawdust.

I've got an uphill battle with my wife - she is primarily looking at her end of things, which is down in the horse barn (lower floor) and is fine with just having some kind of 'door' that she can open to let the sawdust fall out into her wheelbarrow (one of the deep ones with the bicycle tires), and does not mind wheeling that sawdust to each stall. She does not want an investment in a blower system, she just wants to open that door and let the sawdust fall through.

But on my side, without a blower system, I've got to have a gravity fed system which means the hopper will have a slanting floor leading down to a central trap door (downstairs). It will be a minor pain to build such a hopper, and a major pain to shovel the delivered sawdust into it. Without a blower system I will not have any choice over where I'm going to put the hopper.

Right now we get the wood pellet bedding delivered and for an extra few bucks they will stack it where we want it - I come home from work and its all done. Now I'm going to come home and there will be a big pile of sawdust waiting for me! I hope its not raining when they deliver.

Matt - This is more like the price range that can get approved for the budget. If I can use it just on the 'storage' end - taking the delivered sawdust and moving it into the hopper - that will reduce my work significantly.

I wonder if I can incorporate a dust collection system (which I don't have but would like one) and this sawdust moving system into the same system.

I am really getting curious about how steep the angle on the sloping floor has to be in order for the sawdust to roll down it.

gotrocks - I'm checking out the web site for Penn State Industries. Now I'm getting an idea of what is out there.

sandman2234 - that may be a little over-powered for my use, definately for my wallet.

acs55812 - we are looking at sawdust, not wood shavings. Sawdust seems to be easier to handle and pick through than shavings.

patrick g - thank you, we may just do that (run a bare metal grounding wire) if we go that way. I am trying to find a way to have a flexible hose, to reach into the delivery truck and pull it out.

bullridin fool - we will have to talk. I'll PM you. PS I know one or two bullriders in our area..

schism - thanks - I take it that the possibility of explosion is always to be factored out of the equation.

soundguy - thank you. See my previous paragraph on who will be doing the most sawdust moving.. The farther away from the barn, the more (new) work I'll be taking on.

tcarter1 - now we are moving farther away frmo an air system. Is there another system - an old fashioned 'barn elevator' type system I can use to move the dumped sawdust up into the top of a hopper?


Thank you every one.

Pete