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Spark arrestor for Laser exhaust/Dust collector

Spark arrestor for Laser exhaust/Dust collector

Spark arrestor for Laser exhaust/Dust collector

(OP)
My company is getting ready to install a new Laser just after the first of the year.  After paying $1500 for our first spark arrestor and recieving little more than a box with some baffles in it, I have been charged with building the spark arrestor for the new filtration system.  I would like to avoid this box of baffles design as it is quite restictive to air flow.  Has anyone out there built their own spark arrestor or have any design ideas?  
   The last lasershop i worked in had just installed their own arrestors after having a dust collector fire, but i don't know how they have performed since then.  Their design was basically a 2 1/2 foot long cone, made of 12ga steel perforated with 3/8ths holes every 3/4s of an inch.  the tip was pointed into the wind, with the large end being the same size as the duct(20" round)   The theory was that the "spark" would be deflected against the duct wall by the cone.  This would cause the spark to be seperated from it's pocket of oxygen as well as stopping it's forward momentum.  This seems much less restictive than the standard box with 6-180 deg. turns and 6 large baffles to me.  What are your thoughts???  I am open to any advice!   Thanks, Dan

RE: Spark arrestor for Laser exhaust/Dust collector

This is amazing; your message has already been cached and indexed by Google.
;--
The few spark arrestors I have disassembled generally had small passages, a lot of surface area relative to the net flow area, and a net flow area a little bigger than the next most restrictive element in the flowpath.  E.g. USCG approved spark arrestors for carburetors, and US Forest Service approved exhaust spark arrestors for motorcycles.

So, yes, they amounted to a box of baffles, but they were clearly not designed arbitrarily.

If there's an approval authority for dust collector spark arrestors (I couldn't find out), there should be design standards or performance standards available.

;---

Whether there is such an authority or not, if you roll your own, and there's a fire ...

who you gonna call?

Mike Halloran
Pembroke Pines, FL, USA

RE: Spark arrestor for Laser exhaust/Dust collector

Lots of baffels and flow reversals is how they work.  You need them.  You need to give the sparks time to cool while also preventing too much dust from collecting.  I have seen designs using chevron baffels, that might be a good compromise.

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection
http://www.trent-tube.com/contact/Tech_Assist.cfm

RE: Spark arrestor for Laser exhaust/Dust collector

Dear Dan;

Typically Drop out boxes are used for spark arresting in Dust Collection systems. These are often just single baffle devices, carefully designed to slow the air flow down enough to allow the heavier hot material to drop into a hopper below the baffle.

As well, dust collection systems designed for hot and combustible dusts are heavily regulated by the NFPA (National Fire Prevention Association). It sounds like your system was built with only non-flammable dust collection in mind.

NFPA has complete dust collection specs available on the web, try a google search.

Best Regards



Adrian Dunevein
AAA Drafting Services

www.aaadrafting.com
http://home.cogeco.ca/~adunevein/

SW2006 Office Pro. SP4.1

RE: Spark arrestor for Laser exhaust/Dust collector

Many off-road vehicles use spark arrestors. I'm not sure what the design specifics are, but they have to flow a lot of hot gases so maybe worth a look? I have also seen screens over the exhaust pipe, but I think this was on lumber harvesting machines which work around a lot of tinder.

ISZ

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