Hello
To make my workshop healthier, I am planning to install some pipes an hook up my 1 hp dust collector. I have a tablesaw, a bandsaw, a jointer/planer and a router table. I am planning to build a “backbone” and then hook up the individual machines to it. Because the collector is a bit week, I must be careful not to waste its power on a poorly designed system. So I am asking myself; should the blast gates be mounted closer to the backbone or near the machine? I would find it more comfortable if the blast gates was close to the machine (red), but I fear that this would decrease the performance.
Does it matter?
Kind Regards
Mat Hess
Replies
Mat,
I'm certainly no expert but from my understanding it doesn't matter where the blast gate is. What matters is the length, diameter and material of the piping.
It sounds like you are trying to make a DC "system" out of a unit that was probably designed to be hooked to one machine at a time. To get decent results, you will need to be careful about your piping.
You will get more efficiency loss from flex pipe than rigid. Use the biggest pipe possible and keep it as short as possible. Keep the bends gradual.
Best of luck with your system!
Mack
"Close enough for government work=measured with a micrometer, marked with chalk and cut with an axe"
Matt,
If you haven't visited Bill Pentz's web site on dust collection, I would highly recommend it. He recommends keeping the blast gates as close to the main or lateral lines as possible. I am not sure of the reason for this but that is what he recommends. My guess is that it reduces turbulence which in turn reduce efficiency.
I have most of my blast gates directly off of main lines. It allows me to isolate zones within the system.
My thinking is that the cyclone has to pull less air out of pipes, and is faced with fewer leaks in the system. It makes every run fairly short.
Works great, now I just wish they were automatic.
Edited 1/1/2009 11:09 am ET by sroxberg
Penn State Industries offers a "green Box" automatic blast gate system. (I forget what they call it.) It really works great. My only suggestion would be to get the little coils to activate the DC/gate as opposed to the vibration pads. They are easy to install and they are trouble free.Frosty"I sometimes think we consider the good fortune of the early bird and overlook the bad fortune of the early worm." FDR - 1922
Following up on Mackwood's comment, and looking at your diagram, I see a major drawback in your set-up, to wit: the table saw is the longest distance away from the dust collector. With a small (1HP) collector especially, the table saw should be as close as possible to the DC, as it takes the most CFM to pull the dust. Keep any flexible hose to an absolute minimum.
I disagree the table saw is bad, but the jointer/planer produces more chips. If these two have poor airflow they'll plug up the system.
Agreed -- I missed the fact that he has a combination machine in the bunch. My jointer is very easy to collect from, in a pinch can use a big ol' Craftsman 16 Gal vac. But the planer is a whole 'nother story.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
I'm actually just finished updating my dust collector... (I've still got a little way to on the chop saw and router table.)I've had problems with a planer (not my shop), exactly that. Not enough airflow to clear the chips. The hose started to plug ad then it was worse than having no dust collection. The machine plugged up. What a mess.I've got pretty good airflow to my machine, including a blade shroud. But I still get some dust in the cabinet. Not much, but it's enough that I keep track of it. The dust in the cabinet isn't my main worry, its the stuff that the blade kicks out on top. In my view a 1HP collector isn't strong enough to collect reliably from both points.
"The dust in the cabinet isn't my main worry, its the stuff that the blade kicks out on top. In my view a 1HP collector isn't strong enough to collect reliably from both points." Yep! Spot-onforestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Mat,
I asked the same question not tool long ago. Bill Pentz recommends them as close to the main line as possible. It reduces the exposure to any leaks and any other inefficiencies.
However the general consensus is to put the blast gates where they're accessible and convenient. The worst thing you can do with your system is to leave multiple gates open. In my case the main lines runs on the ceiling 10' up... so they're at the machines.
Dust collection isn't as simple as most people think. The airflow is a function of blower size, ducting size, and overall static pressure in the system. Further you'll need a minimum speed to keep chips suspended, people often forget this and recommend silly pipe sizes for underpowered blowers.
I the end 1HP is adequate for chip collection, if you want to capture fine dust you'll need to upgrade. My suggestion is to keep this as low cost as possible so that when you really want to get serious about it you don't have much money invested.
It won't matter where you place blast gates in a system as long as the pipe joints are suitably sealed from leaking.
You definitely don't want to connect branch lines via Tees. You have to use wyes in order to minimize air flow losses due to turbulence.
Wyes or no, I doubt whether your 1HP dust collector will be up to the task of running your proposed system. The smallest cyclone system offered by major manufacturers is 1.5HP (Grizzly) and, at 1025 CFM with a 6" inlet, that would be about right for what you propose. I doubt that your 1HP system would top 600CFM at the intake, so line losses would probably reduce flow and velocity below what you need to handle the load, especially from a planer.
Finally, anything other than a cyclone type with a 0.2 micron pleated filter will not control the most hazardous particles. Another poster suggested looking on Bill Pentz' site, where he makes the case that bag type machines are just chip collectors but they pass the fines right through. You probably wear a good dust mask while operating saws, sanders and such, but those 0.2 to 2 micron fine particles stay suspended in the air for hours and they are small enough to get right into your (and your family's) lungs long after the machines that generated them are done cutting.
Oneida has information on system design available online. Sandor Nagyszalanczy's book, "Woodshop Dust Control" is also a very good resource; available from Taunton Press.
good luck
BruceT
Edited 1/4/2009 2:32 pm by brucet9
Thank you all who have helped me with your ideas and knowledge. I visited Bill Pentz' website. The information presented there really opened my eyes. I now am aware that my underpowered system with poor filters is an inadequate solution and a health risk. I am now building my own cyclone from bills plans.
Kind regardsMat Hess
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