Blast gate ?

[PeterTorresani]

I need to buy/make some blast gates for a work project. Any recommendations on the best way to go. I need to be able to power them with air or 120V.

[Don Baer]

Peter I did a search on the forum and came up with anumber of hits about the subject. If it were me I'd make my own.

In terms of opening them electrically now thats another matter.

here is a sample.

http://www.sawmillcreek.org/showthread.php?t=19783&highlight=blast+gates

[Ken Garlock]

Hi Peter. I did some research on automatic blast gates and found these gates (http://www.nordfab.com/auto_blastgates.cfm) .

The major drawback is the total size of the package. A 6" gate had a total length of 20" to accommodate the sliding gate and pneumatic piston. That is just to large to suit me. Plus, you can be sure that they are expensive. :(

[Chris Padilla]

Anything made by Nordfab will be expensive. You can bet it'll be darn good, darn nice, darn well put together, but darn expensive, too! :)

[Jeffrey Makiel]

Peter,

I built some electric blastgates for my home shop. Actually, they should be called "dampers" since they use a swing gate design instead of the usual sliding gate. That is, the blade remains in the airstream and rotates parallel to the airflow when open by a mechanical solenoid, then rotates to a closed position by a spring. They are fairly straight forward to build, and the materials are readily available. They are also inexpensive...about $30 each to make.

Some thoughts:
1. Even though the blade is in the airflow, I was concerned that clogging will be a problem. However, this was not the case;

2. They do leak when closed due to clearances that must be maintained between the damper blade and interior sidewalls of the damper box;

3. Although mine are electric, pneumatic actuators can be substitued. However, pneumatic stuff is fairly expensive and is overkill as far as needing this amount of power to operate;

4. They are fairly compact, but will cause some degree of pressure drop in your system...at least theoretically. But I think it is quite insignificant.

My original dampers (now 12+ years old) are 4" dia with alot of cycles on them. The electrical circuit also activates a simple relay to start the dust collector machine. I really enjoy this convenience. EcoGate makes electrically opeated blastgates, but the 6" diameter gates are fairly expensive. Besides, I like to show people my Rube Goldberg invention!

To see the plans I used for the older 4" dampers, visit my website at http://geocities.com/autodamper/ and download the pdf file. I recently built some 6" dia versions with some minor improvements and hope to prepare plans for them too. I only have two of the newer 6" versions in use, but they are working well so far. Here's some pics of the 6" damper...

http://i3.photobucket.com/albums/y84/Beff2/DSCF0138.jpg

http://i3.photobucket.com/albums/y84/Beff2/2004_1231Image0008.jpg

-cheers, Jeff

[Charlie Plesums]

Jeff - great design... remarkably simple and apparently effective.

Welcome to the creek... Hope to hear lots more from you

[Chris Padilla]

Jeff, I almost hate to say this but "those things are darn cute!" Very nice design...I love it! :)

[John Gregory]

I need to buy/make some blast gates for a work project. Any recommendations on the best way to go. I need to be able to power them with air or 120V.

Check this out (http://www.ecogate.com/)

Jeff, I looked through you PDF file, Telling you it looks so professional is an understatement. You did an absolutely awesome job documenting your project. Thanks for sharing it with everyone.

John

[Bill Lewis]

Pretty Cool Jeff.

I didn't know you could still get those solenoids any more. I've got a couple of them laying around that are at least 40 years old. My father salvaged them out of some old washing machines and used them to build an automatic horse feeder in the 60's. I doubt you'll find them in washing machines these days, but for the real scrounger's out there you may be able to find them in some old appliance repair store.

[Jeffrey Makiel]

Bill,

The solenoids are available at Grainger for about $22 each. They are also available at McMaster-Carr but are more expensive.

From Grainger...it's the 4x240
http://i3.photobucket.com/albums/y84/Beff2/untitled.jpg

I've had one solenoid fail in 14 years of use on one of the eight dampers in use. It happened early on with a prototype damper design. A simple modification to the damper and I've had no trouble since then. The solenoids are fairly durable, but can be damaged if something binds during the initial latching throw that would prevent the solenoid from fully seating when energized. In the instruction booklet, I recommend the use of a 4A fast acting fuse to help protect them.

cheers, Jeff

[Bill Lewis]

Jeff, great folowup.
I actually read the write-up from your site early this morning to find the Graingers reference. I guess I should have read what I wrote (in response) a little more carefully, but it was too early.

[Mike Stanton]

There are great I have been wanting to do something like this for a long time. Thanks I am now going to make some. Mike :D