Industrial Scale Dust Collection #8: wrapping it up

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Blog entry by Mainiac Matt posted 07-29-2016 05:44 PM 1026 reads 0 times favorited 15 comments Add to Favorites Watch
« Part 7: crane day cometh... Part 8 of Industrial Scale Dust Collection series no next part

I just recently realized that I never wrapped this blog up. So today I will add some pics of the final installation and a few notes about our trials and travails to GC this project in-house, with a second hand system.

Here it is from the outside….

In this pic you can see the tower, the 28” diameter “suck pipe” coming out of the building and the material transport loop, which has it’s own blower and transports the debris that drops out of the rotary air lock (think departments store revolving door) into a modified tractor trailer. We sell the dust/chip debris to a wood pellet plant and empty it every 6 – 8 weeks. We have to maintain two modified trailers in road worthy condition, but because we haul them ourselves, we get paid ~ $1,000 per load.

Here you can see how the material transport loop goes into and returns air from the trailer.

Here you can see the 60 HP blower, the discharge muffler/silencer, and the photo eye sensor (red) that signals the alarm box to switch the abort gate. The silencer was not part of our original plan, until we fired up the blower and heard how loud a 20,000 cfm blower really is. It is a custom engineered device that cost us $4,500. But it really works. You can stand next to the blower and have a conversation without raising your voice, and noise level inside the shop is lower than with our previous system, which only moved 9,000 cfm (on it’s best day).

Here you see the high speed abort gate up on the roof. Return air is normally sent back into the shop (try heating a 20,000 s.f. shop in January when you’re continually sucking 20,000 cfm out of it. The ceiling is 14’ tall so that means the atmosphere is completely exchanged in 14 min.). When the alarm system senses fire in the return air pipe, the abort gate de-energizes an electro magnet and the gate slams into the bypass position in less than 500 msec.

-- Matt -- I yam what I yam and that's all what I yam

15 comments so far

View J123's profile


363 posts in 3397 days

#1 posted 07-29-2016 06:02 PM

So I’m curious as to the goings on at your place. Do you have other business that requires a loading dock and baghouse?

Speaking of baghouses, it doesn’t get serious until you are charged with changing all 10,000 bags in a power station baghouse, oh, and there are 2 houses per unit, three units at the station… or, even worse, they all get destroyed in minutes due to acidification… enjoy.

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Mainiac Matt

9862 posts in 3386 days

#2 posted 07-29-2016 06:28 PM


I work at an industrial packaging manufacturer and we have two shifts banging out crates and pallets. We have a second 10,000 s.f. woodshop that has a SELCO panels saw, a CNC router and a semi-auto pallet making machine that has it’s own DC system. Our business is built in somewhat of a campus format, with additions being added over the years, so we don’t have the luxury of having any one building that is big enough for the entire operation.

And your absolutely correct… I quickly became aware that as far as bag houses go, if you classify them as small, medium and large, this bag house is at the larger end of the small category.

-- Matt -- I yam what I yam and that's all what I yam

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Mainiac Matt

9862 posts in 3386 days

#3 posted 07-29-2016 06:34 PM

Got juce….

Fortunately we had a 480 3 phase panel with enough capacity to pick up this unit that was only ~60 feet away. None the less the electrical work cost us ~ $8,500.

Here are the disconnects mounted outside at the system…

and here is the remote alarm panel, which is mounted inside in the loading dock area.

and here are the remote indicating lights so the shop supervisor can monitor the system at a glance from anywhere in the shop.

and here’s the alarm control panel (Grecon) which was recycled from our previous system. These systems are big bucks…

-- Matt -- I yam what I yam and that's all what I yam

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Mainiac Matt

9862 posts in 3386 days

#4 posted 07-29-2016 06:42 PM

Ductwork anyone….

When your pulling this kind of air flow you can collapse spiral ducting, so the main trunk lines are welded seam custom fabricated ductwork. Then we stepped down to quick duct, as we are forever changing things around and we want to be able to do that ourselves. The tin knockers contract was over $40K.

Here’s the 28” header where it goes through the wall to the bag house outside. You can see where our old system (which was demo’d) went out near by. Note the plumbing fixtures just above the duct. This is the second part of the fire suppression system. If a spark or flame is detected, there are two nozzles that are activated and spray water into the header to extinguish the fire, hopefully before the entire bag house goes up in flames.

Here you see the photo eye on the header. These have to be down stream of your last machine connection, and far enough up stream of the spray nozzles, as to allow the system to trip and spray before the sparks are sucked out of the building.

And here’s the water tank for the spray system.

-- Matt -- I yam what I yam and that's all what I yam

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Mainiac Matt

9862 posts in 3386 days

#5 posted 07-29-2016 06:50 PM

We already had a return air header in the shop, but we were more than doubling our air flow and didn’t want the guys to have a hair dryer blowing over their heads. So we cloned that header and split the return air header into two streams with a large ‘Y’ fitting down stream of the abort gate on the roof. The ductwork then comes in through the roof and goes through the trusswork to the points were it drops through the ceiling. It is then distributed down the length of the shop… As mentioned, this is very quiet.

The only problem we’re having is from warm moist air from the shop (where we cut a LOT of green lumber) going up into the return air pipes over the weekend when the system is off. In the depths of winter, this air condenses in the pipes in the freezing cold attic space, and then come Monday morning, when they fire up the system again, those “lucky” enough to be standing in the right place get a shower. So we’re having the tin knockers come back and insulate the ductwork in the attic before the weather turns this fall.

-- Matt -- I yam what I yam and that's all what I yam

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Mainiac Matt

9862 posts in 3386 days

#6 posted 07-29-2016 06:58 PM

I oversaw this project with a budget of $90,000 and it was a massive headache from day one.

The bag house was >20 years old and had four different size sock cages in it. Also, some of the cages were damaged. So we had cost overruns as we purchased extra bags and replacement cages. Fortunately, the machine broker we purchased the system from is a division of a company that makes the filter socks, and they sold us the replacements at distributor cost. The muffler was another cost over run. Then we had scheduling snafus caused by our maintenance crew miscommunicating, not following specific instructions and having some unfortunate mishaps. This wound up causing the tin knockers having to do extra work that they rightly passed the cost of onto us.

Even so, we came in at ~$100,000. But the real problem was that it dragged on for 6 months (planned on 3).

-- Matt -- I yam what I yam and that's all what I yam

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Mainiac Matt

9862 posts in 3386 days

#7 posted 07-29-2016 07:03 PM

And this is the pulse of the system…. the differential pressure across the bank of 124 ten foot long and six inch diameter filter bags.

With brand new bags, we ran just under 2” water column D/P. Here you see that with “seasoned” bags, we’re running just over 3”.

When D/P starts climbing up, it’s a sure sign that the rotary air lock has been bridged and the bag house is filling up. So we have to monitor it daily.

Just don’t ask me how I know this :^(

-- Matt -- I yam what I yam and that's all what I yam

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Mainiac Matt

9862 posts in 3386 days

#8 posted 07-29-2016 07:08 PM

I hope this was an interesting blog and that it was worth your time to read.

In the big scheme of things, our wood operations are medium-large sized for the New England market place. I’ve seen a just a few that are larger, and several that are smaller.

But we’re a growing and profitable company, so I’m happy to be doing my bit to keep us moving forward.

If we had simply called in the Torit rep and said “how much” and purchased a new system to these same specs. with their distributor acting as the GC, it would have cost us upwards of $300,000.

-- Matt -- I yam what I yam and that's all what I yam

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21400 posts in 2914 days

#9 posted 07-29-2016 07:45 PM

Looks great Matt. You did yourself proud.

-- Bill M. "People change, walnut doesn't" by Gene.

View rhybeka's profile


5025 posts in 4179 days

#10 posted 07-29-2016 08:02 PM

sweet job, Matt! It was interesting even to a non mechanical person like me :)

-- Beka/Becky - aspiring jill of all trades, still learning to not read the directions.

View bruce317's profile


404 posts in 1880 days

#11 posted 07-29-2016 09:27 PM

Matt, I retired from a foundry, as a millwright. Over the years I spent a lot of time in a bag house. One of the nastiest jobs in the plant. Thanks for the memories.

-- Bruce - Indiana - Sawdust is just, MAN GLITTER!

View Richard's profile


1944 posts in 3747 days

#12 posted 07-29-2016 11:02 PM

So Matt , I guess after this a 5hp system in a two car garage shop would be a weekend Project for you now. :)
Glad you made it thru all that in one piece.

View Roger's profile


21054 posts in 3861 days

#13 posted 07-30-2016 01:10 AM

That is for sure some serious dust collection.

-- Roger from KY. Work/Play/Travel Safe. Keep your dust collector fed. [email protected]

View lightweightladylefty's profile


3630 posts in 4770 days

#14 posted 07-30-2016 03:56 AM


What an undertaking! At $1000 a load, you’ll recoup the $100 grand in about 13.47 years . . . if you don’t bother putting any money into maintaining the system. ;-)

Thanks for sharing such an interesting blog.


-- “Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety.” Benjamin Franklin -- Jesus is the ONLY reason for ANY season.

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Mainiac Matt

9862 posts in 3386 days

#15 posted 08-01-2016 01:33 PM

L/W that’s certainly one way of looking at it, but we normally look to recover the costs of capital investments in 2-3 years, not 13 :^o

Though we estimate that recirculating the air back into the shop will also save us 1,000 gal. of LPG a year, so that also helps the financial side.

But this project was really justified by other reasons:

1. We do not want our woodworkers health compromised by exposure to wood dust.
2. My research showed that we were not in compliance with NFPA 664 (Prevention of Fires and Explosions in Woodworking Facilities). And while the garden variety OSHA inspector doesn’t know much about these detailed regs, I was advised that if we had a fire, they would send in the subject matter experts and nail us big time.
3. We were wasting a lot of valuable time clearing plugged up hoppers from our old 9,000 cfm system
4. We had problems with inadequate suction on some of the remote saws, resulting in them getting plugged up with dust and having to be shut down to be cleaned out.

-- Matt -- I yam what I yam and that's all what I yam

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