Improving Dust Collection Efficiency

When installing a dust collection system, you’ve spent good money on the biggest collector you can afford, and then are trying to get it to maximise its range to collect from as many machines as possible over the longest distance needed to maintain the shop’s machine layout.

One very common aspect of this is to install blast gates so that machines that are not currently being used are not unnecessarily having air drawn from them, decreasing the amount of suction at the tool in use.  There are a number of different blast gates available, with one of the most common ones on the market being the plastic 4″ – 4″ blast gate.  They are a low cost solution that seemingly works well in shops across the country, and world (I guess).

Don’t know who designed the original, that is now so often copied, but all I can say is…. it’s bloody stupid!

The problem: the bottom corners of the gate (in the channel where the gate itself slides) quickly get filled with crap, and once that happens and the shavings / dust etc get packed in there, the gate cannot ever close properly again, leaving a permanent leak through every gate that is (theoretically) closed.

Original, Clogged Blast Gate

Original, Clogged Blast Gate

Here is a very typical blast gate, and in the very typical state of being so blocked in the lower corners that this is as much as it can close.  Looking at the opening this leaves, you can see that it wouldn’t take too many gates in this state that the amount of leakage would add up to being the equivalent of a fully open gate. A complete waste of suction.

One tip I’ve come across in the past, is to cut off those lower two corners, so the gate effectively becomes self-cleaning.  When the gate is closed, the slide blocks the resulting holes.  When it is open, there is a minor additional leakage caused, but nothing like the loss from a single, unmodified closed gate.

Modified, and properly closed again

Modified, and properly closed again

Here you can see the protruding corners of the blast gate slide.

Exposed corner

Exposed corner

And the small hole that now exists in the corners.

I’m not sure if this mod is the best way (or the neatest) – I’m sure I saw (or at least read) about this mod in a mgazine somewhere!

So that is the basic concept to the modification, and it does work.  However, it isn’t the neatest version, and so my amendment to the concept is to drill the corners out, allowing the slide to continue to push dust clear, but better maintaining the overall physical (and visual) integrity of the blast gate.

During the drilling of the corner, the dust that is packed in the corner is immediately apparent.

Dust Packed Corner

Dust Packed Corner

I’m much happier with this second version.  Also because it is my take on the idea, rather than a copy of someone else’s (although I’ll be stunned stupid if I’m the only one to have ever thought of it!!)

Modified Blast Gate (V2)

Modified Blast Gate (V2)

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