Dust collection questions

Paul Downes

Member
Messages
959
Location
Westphalia, Michigan
I'm in the process of getting a dust collection system set up for my shop. I did some work for a commercial trim shop and the owner gave me a boatload of 6" spiral pipe so this is what I'm going to use. He also has an old Torit dust collector he said I could have. It has a 3 phase motor on it so I am probably going to swap that out with a 5 hp. TEFC single phase motor.

My shop is 18 X 32 in size so I plan on running the pipe along the ceiling @ 11 ft. with 6' drops as far as I can come down the wall. So far it looks like I will only need one run on one wall to get collection to most of my machines. They are; table saw, band saw, sander, jointer, lathe, and a floor sweep.

My questions are; Is the shortest length pipe best? And, is it an issue to have a system where the blower is too big? My understanding is that most systems are too small. I have been reading on Bill Pentz's website to try to get my head straight on this.

I do plan on running plastic 4" hose to the table saw because it is in the middle of the room and I don't want a drop hanging there.
 
Air flow is what moves the stuff---All of it---the larger chips and shavings---the 1 micron stuff you cannot see.

Therefore do all that you can to keep runs short, turns gentle (eg. two 45 els to make a 90 degree turn), smooth insides in ducting whenever possible (It would be very difficult not to use some flex in a system. Keep it to a minimum) and be sure plenty of air can get into the system (If the input air is choked down the air speed, static pressure, etc. will all go to pot.).

For the last part, choking, think of the vacuum cleaner ads where the little vacuum cleaner holds up the bowling ball. Yeah, it holds up the ball but not one molecule of dust is going through the vacuum cleaner hose to the dust bag. The air has to move; anything you do to impede that air movement is reducing your efficiency, unless you want to hold up a bowling ball.

Enjoy,

JimB
 
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There is a line between theoretical performance and practical experience. I'll take practical myself.

My shop room that has all of the milling tools is 20x24. From my 3hp DC, I have two 7" runs going opposite directions around the ceiling at the top of the wall (I have 8.5' ceilings). I change to 6" pipe at the first drops that are about 7' from the corner where the DC lives. At the next drops each way, I change to 5". All of the machines end up with 4" pipe into them. I get great collection from all of them. I have two floor sweeps that are 4" pipe from ceiling to floor that will suck up anything that gets within a foot of them and will hold the broom if I turn it loose.
 
I will have to run the piping from one location because the dust collector will be located outside the shop in a lean-to. I just moved my air compressor out there and am really enjoying the muted noise. I made a small room in the lean-to when I put it up last year with this in mind. The Torit is not a cyclone and so I am thinking about building a cyclone out of metal to add to it. I will probably have to think about running the filters back into the shop or I expect it will get quite cold during the winter months. I have been pricing out some long radius elbows and 45's and "y"s . I may try to make my own y's because I have way more pipe than I need.
 
Paul - in reality it is AIR VELOCITY that keeps the dust suspended so it can travel through your pipes into the collector. Large CFM machines will allow you to have longer runs, connected to more tools while still maintaining a minimum velocity of air at or above 4000 feet per minute. This seems to be the magic air speed to keep DUST suspended - and dust is what we need to collect to protect our lungs. Bill
 
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