Position of blast gates

[Jonathan Oman]

Okay, I did a google, but did not find the answer. For a dust collection system, where should the blast gates be placed for each machine drop? Six inches from each machine, or just past the 'Y' coming from the main line? Does it matter?

Thanks, Jon Oman

[Gene T]

[Nova]

It depends on how much you like to walk.

-- Jack Novak Buffalo, NY - USA (Remove "SPAM" from email address to reply)

[igor]

FWIW -- I need to put a damper in my HVAC system, in the main trunk supply that runs from the basement air handler/furnace up to the attic. There are two "main" trunks - one for down stairs one for upstairs. I asked my HVAC guy whether I should make a point of putting the damper as close to the plenum at the air handler and he said it did not matter much.

Now, with the recent debate here over air flow there may be a scientifically "correct" answer to your question. However, it would seem that if (theoretically) the blast gates and each hose section were air tight that it would not matter where a gate went. That being said, whether the real world fact that there will be some leaks makes a difference, I dunno. -- Igor.

PS: This being said, my first instinct is/was that Gene is right. I know it is often said that one is supposed to take that first instinct on SAT test questions, but it may not be true of DC system design.

[G. Lewin]

So long as the line doesn't leak, it is irrelevant where you put them. Oh, I suppose if they were right up flush with the main line you might see a difference in the third decimal place or so, but for all practical purposes, it doesn't matter.

Put them where it is most convenient.

G

[J. Clarke]

Big question--how powerful is the dust collector and how strong are the ducts? All ducting between the blast gate and the dust collector needs to be sturdy enough to not collapse when all the blast gates are closed with the power on. If you're using a shop-vac it's not that much of an issue--if you're using a 5 HP cyclone then it's another story.

There's also a convenience issue--you need to have the blast gate close enough to the position where the machine operator normally stands that he can operate it without undue strain or contortions or reaching through a "danger zone".

[Frank J. Vitale]

It is a good idea to put them in a place were the duct is vertical. It minimizes the build up of dust in the slot that the gate rides in which keeps you from full closing the gate.

[Jonathan Oman]

Thanks everyone for your suggestions. Based on the answers, I have decided to place the blast gates close to each machine. In answer to one of the questions asked, my DC is a Jet DC-1200C. It is the 2HP, 240volt, canister model.

Thanks, Jon Oman