Based on the URL, I plan to use sewer & drain pipe. I will use wye's and short (1-2') flex hose.
Should I try 6" duct? If I read this correctly, he is saying that no reduction should be done.. so I really have to convert all dust ports to 6". That's possible for my TS, SCMS, and jointer, but not very practical for my planer, BS, and DP.
I have a 23x18 shop. Planning to place DC in corner.. and duct along the 23' wall, with wye's off to a TS/Jointer/Planer/BS area.. (closest to DC), SCMS area, and DP area
DC | BS \ | \ | J/TS__ / P | | | SCMS_/ | | | | DP_ /
IMHO, 6" is probably a big for a 1.5HP unit - real world CFM is probably lower than advertised - 5" would be a better match. Velocity needs to kept up, or the material falls out of suspension. Metal ducting is probably more widely available at 5" and requires no grounding wires. I believe the no reduction rule applies to runs, not connection branches - but make up air has to come from somewhere to keep the velocity up. In consideration of the economics of it all, I believe short 4" runs to equipment would be fine. Various leakages would make up some of the difference - or an inlet relief flap at the end of the run.
Oh, God - here we go again... Convention? Elimination of static buildup?
Just ask a midwesterner about silo explosions. Far courser material, yet it CAN explode. Have I ever seen it? No - maybe 'cause they are grounded by convention...
I just set up a 1.5 HP Penn DC in my 20'x20' shop using 6" sewer & drain pipe for the main lines and 4" sewer and drain for branch lines to each machine. It will suck the chrome off a trailer hitch! I did not ground anything and plan to notify the Wreck immediately if and when there is an explosion.
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> I have the Jet cartridge 1.5hp unit; rated 1100cfm
Yep, here we go again. A) Silo explosions are not caused by static, but usually by an electrical spark on faulty equipment. The energy in a spark is far greater than energy produced by a static discharge; it also is of longer duration B) the material that causes silo explosion is not far courser material, it is actually very fine, very concentrated dust produced as a result of moving very many TONS of material in a short period of time.
The archives should provide sufficient information to rehash this for the curious.
Probably picking nits here... Although I understand how you came to these conclusions, for the record, I never directly stated that static caused silo explosions. I used that as a rational for why dust collectors are often grounded - in a different paragraph. But by the same token, it could happen. A spark is a spark. Lightning, electrical equipment, sparking contacts in switches just thrown are all potential sources of ignition. This is why they have specialized equipment that is sealed to prevent this from happening. A Kettering ignition system has a fairly short spark duration - but it ignites a highly pressurized cylinder full of atomized fuel - every time. (Hopefully...)
I also never said course material was the fuel for the explosion. Of course it is finely atomized dust particles. But the average bystander sees corn, or wheat - larger material than sawdust - which, incidentally, contains many fine dust-like particles itself. As anyone who has ever used a dust collector can attest, the friction of sawdust moving through a plastic pipe generates static.
With this said, a friend has a picture frame shop. When he installed his dust evacuation system, the inspectors required it to be grounded. Why? I don't know. Probably the same reason they don't allow PVC air lines. The chances are 1 in 10,000, but there apparently IS a chance of something untoward happening. Have I ever seen it or heard a substantiated case of it happening? No!
I would say, that for myself, a couple of dollars worth of wire is cheap insurance, and of benefit if only to eliminate that annoying static shock from touching an ungrounded, static charged thingamabob in the DC's path.
I'm a midwesterner. Trouble is I don't use my shop for a silo.
It can? Have you proof? Can you refer me to someone whose shop has *blowed up* onna 'count of PVC pipe and their dust collector? Can you refer me to a fire department,,, OK, I think you know I know you can't.
Hmmm... folks are getting mighty testy over this one...
I could care less if you ground your DC or not, I'm not twisting any arms - just playing devil's advocate. So don't take it personally.
But, as stated in a previous post:
... a friend has a picture frame shop. When he installed his dust evacuation system, the inspectors required it to be grounded.
Why? I don't know. Probably the same reason they don't allow PVC air lines. The chances are 1 in 10,000, but there apparently IS a chance of something untoward happening. Have I ever seen it or heard a substantiated case of it happening? No!
I would say, that for myself, a couple of dollars worth of wire is cheap insurance, and of benefit if only to eliminate that annoying static shock from touching an ungrounded, static charged thingamabob in the DC's path.
Good grief! Almost any fine organic (and some metal) powder can be explosive (or maybe just burn fast, depending on your definition of explosion). No one needs to prove it, it's been demonstrated time after time in class rooms, at safety shows, on television, etc.
However, the stuff that ends up in my nose when sawing wood, is, I think, way to coarse to explode. It has to so fine that it almost will not settle but just stays in the air. I can't imagine anyone working in such conditions. And he/she would need to worry much more about their lungs and eyes.
I have no idea if wood dust has ever caused an explosi>
I'm new to the group and don't want to get roasted here, but I have a tale to relate. Many moons ago I was cleaning out my shop after a long winter of woodworking projects, I use my compressor to blow the dust that had accumulated in the shop into the air then vacuumed up the dust that settled on the floor. I repeated this a few times until my shop was as dust free as the day I built it. It was not until later in the day that I learned the power of dust explosions. I had taken all the shop scraps and what not out to the burning barrel on the back of the property and was finishing up with yard waste when I remembered that the Shopvac needed to be emptied and the burning barrel seemed like a good repository for the contents. Now I will give you that a 45 gallon drum filled about 3/4 full of embers has slightly more energy than a static electricity spark, but the resulting 40 foot fire ball was enough to instill in me a healthy respect for the explosive quality of dust. I will for forever remember the wall of heat that over took me while I was admiring the way the dust had billowed up in the rising gasses of the burning barrel. It was over in milliseconds, left no permanent scars, but has left me with the attitude that I will not take any chances with dust explosions.
Just for fun I Googled dust explosions, perused the results to see if my mileage was not too different to others ( didn't want my first post to be attributed to a raving loony) and I happened upon an image that is a dead ringer for what is seared into my brain. (pun intended)
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don't know how much of this is relevant to dust collectors, don't really care, but for my money if there is a chance of setting of something like the explosion I witnessed and it only takes a couple of dollars and a couple of hours then I'm in.
heckuvalot more. i.e. it was already an open flame with sustained duration
I want someone to tell me how they think that wrapping copper wire around the *outside* of an insulator is going to prevent sparks from occuring *inside* said insulated space. Since static charge builds up as a surface charge, I also want to be shown how having a discharge path on the inside of the collector will actually make the system safer regarding static discharge from the surface charge. One could postulate that having the wire on the inside is actually worse, because a potential from one side of the plastic surface can build up such that a discharge to the wire residing at some distance from the surface results. This can become even more of an issue if the wire becomes airborn, creating a gap for the discharge to take place.
My balls are fine, thank you. I perpetuate no myths. Good Grief, shoot the messenger. I am only reporting facts.
You will notice that I never told anyone to ground their DC system. This stupid thread started (again) over one mention of metal pipe replacing grounding the wire that some install on their PVC systems. Several companies sell DC ground kits to (IYO) misguided individuals. Fire codes in some localities require it in commercial installs. Nothing here should be construed as MY recommending anything.
As for me, I use conductive tubing, because I hate the static attraction that generic plastics generate.
Sort of my point. Any remotely combustible product finely atomized within an oxygen environment will burn at an accelerated rate - and when constrained by the walls of a DC system, *could* result in an explosion. Whether big or small doesn't matter - fire is fire. Apollo Astronauts aren't *supposed* to be char-broiled in their capsule on the launch pad, but it happened.
Nice fireball! Reminds me of my youth & home-made rocket experiments.
Potential for nice fireballs in your house, no less. I, too, tend to err on the side of caution. $3 and 20 minutes? Count me in as well.
Opinions are like as%holes - we've all got one. Oh well, made for a mildly entertaining hour, anyway.
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