# Position of a Blast Gate



## Geppetto14 (Feb 21, 2014)

Hi,

I am in the middle of building a dust collection highway with pipes.
I now need to place few blast gates, 
My setup is simple, I have an 8 meters main pipe, at the end of which is my Table saw, After two meters from the start I have a branch that goes to two other machines. Can I put a blast gate close to the table saw or does it need to be as close as possible to the branches at the two meter mark?

I am scared that if I put the gate too far from the branches that I create lots of empty pipe (6 meters) for air to get lost :-(

I should have paid more attention to physics class 

Thanks
Nic


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## jdonhowe (Jul 25, 2014)

Put your blast gate wherever it is most convenient for you to reach. There is no (significant) air moving in that "empty pipe", so it has no effect on performance elsewhere in your DC system.

In a way, a blast gate is analogous to an electrical switch. It doesn't matter where the switch is for a table lamp- near the bulb, in the power cord, or at the receptacle- it just cuts off current to the lamp, and has no effect on the rest of your electrical system.

FWIW, my physics classes through college junior year had no application directly applicable to dust collector operation.


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## G_P_K (Dec 26, 2015)

fluid dynamics would be a much more applicable field to relate to how a dust collector performs.


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## MT Stringer (Jul 21, 2009)

It would seem to me that if the gate for the table saw was not at the saw itself, the pipe could fill up and create a plug. Mine is attached to the dust port on the saw.


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## Brian T. (Dec 19, 2012)

I sometimes buy carving wood that is beyond my capability to cut to size. The guys in the wood store have an enormous back-room shop of General equipment. All the blast gates are within a foot or two of the machines.


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## UnisawGuy (Jul 20, 2014)

I mounted my gates so the gate slides horizontally to open/close. It was luck as much as planning that I can see all the gates from most of my shop.


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## NickB (Sep 24, 2013)

Air doesn't "get lost", but it does decompress. 

Your system will reach a certain static pressure based on the DC itself, the filter and any air leaks in your piping. What's important is that no matter how much air is in the piping system, this force is ~static~ and won't change until you change one these 3 variables.

The location of the blast gates will determine how much (volume of) air will need to be decompressed in order to reach this limit of your system and that takes time. This "charge up time" is the time it will take between firing up the system and reaching full suction at any given blast gate or even closing one gate and opening another. For a small home shop, it's probably not significant - maybe 5-30 seconds. On very large systems, it could take minutes.

I agree that the gates should be placed for convenience/accessibility, but also add that placing them within sight line of the tool will increase the chances that you'll remember to open them every time. 

Good luck on your dust collection physics experiment


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