Dust Collector Advice

[CMorrissy_]

I am looking into a dust collector unit for our mill room. We operate a 2 roller mil at about 50lbs/min. It runs 6 loads of 2200lbs of malt per day; 5 days a week. We currently have a fan that will pull dust out of the room but it just blows dust into the atmosphere and is not designed to handle that much dust.

I would prefer a unit that can fit inside our 8x8 mill room or somewhere near to that. Any suggestions for units or perhaps what to look for are greatly appreciated.

Cheers,

Campbell Morrissy
Production Manager
Stranahan's Colorado Whiskey

[roc-craven]

What about a wood working dust collector. Easy to find and not to pricey.

Fat fingered on Tapatalk

[TGTimm]

I'll second the vote for a wood shop dust collector. I'm in the process of installing one right now.

You DO NOT want the dust collector inside your mill room. Aside from anything else, OSHA does not want it in the room. The dust collector itself is considered a possible ignition source for a dust explosion, so it must be in its own room, with louvers or a blow-out panel that would direct any explosion away from the main building (I just went through this with Oregon OSHA).

Use metal piping or PVC with a ground wire for the plumbing--again, to prevent dust explosions (check out Goolge images for "dust explosion" if you're not aware, or skeptical, of dust explosions).

The unit I purchased is a Jet 1 hp bag-type collector, 650 cfm, ~$250. I don't want it to pick up grain along with the dust, so I went for a low-powered unit to start with. I'll have it set up and start experimenting with it sometime next week (hopefully). We're in the process of building a room for it right now, and getting the wiring figured out for the electrician (I want it to come on when the grain conveyor and/or mill is activated).

[CMorrissy_]

Connecting the collector

Hey Timm, Thanks for the advice regarding the dust collector.

I think we are going to go with one of the Jet models as it fits our needs for the time being. According to the current OSHA standards we can mount it on the roof, about 15 feet above mill. I was wondering if you could elaborate on how you hooked your mill to the dust collector. Did you use laundry style flexible hosing or did you do a more serious hard line duct work?

Any suggestions you have would be helpful.

Cheers
Campbell Morrissy
Production Manager
Stranahan's Colorado Whiskey.

I'll second the vote for a wood shop dust collector. I'm in the process of installing one right now.

You DO NOT want the dust collector inside your mill room. Aside from anything else, OSHA does not want it in the room. The dust collector itself is considered a possible ignition source for a dust explosion, so it must be in its own room, with louvers or a blow-out panel that would direct any explosion away from the main building (I just went through this with Oregon OSHA).

Use metal piping or PVC with a ground wire for the plumbing--again, to prevent dust explosions (check out Goolge images for "dust explosion" if you're not aware, or skeptical, of dust explosions).

The unit I purchased is a Jet 1 hp bag-type collector, 650 cfm, ~$250. I don't want it to pick up grain along with the dust, so I went for a low-powered unit to start with. I'll have it set up and start experimenting with it sometime next week (hopefully). We're in the process of building a room for it right now, and getting the wiring figured out for the electrician (I want it to come on when the grain conveyor and/or mill is activated).

[TGTimm]

Campbell--

I'm still in the process of setting the dust collector up--mostly getting the shed built for it to live in.

I'll be using Sch20 PVC irrigation/DWV pipes, 4" dia for the main run, with 4" PVC drops to the two sources of dust (top of mill, weigh bin at the grain delivery point from the auger). I plan to hook up a couple of dust collection hoods--a Big Gulp for the weigh bin, a Little gulp for the mill--using the flexible hose for as short a distance as possible (the corrugated hose has a lot more drag than the smooth PVC). A blast gate at each hood will allow me to adjust the suction at each point to ensure I'm collecting fine dust and not grain. Of course, all the runs will be grounded.

Be careful and do your research before ordering parts. The PVC pipe will probably be much cheaper if you source it locally, due to the high shipping rates for it. Most of the fittings are standard PVC DWV fittings, but try as much as possible to eliminate 90s, using two 45s short- (or long-) coupled instead, once again, to reduce drag and loss of suction/velocity. The flexible hose requires special fittings you'll have to source from a woodworking supply (or Amazon). These are couplers, female slip-fit on one end, male threaded on the other to fit the corrugated hose. The special "bridge" hose clamps are worth the money for hooking up the hose. The Big/Little Gulp hoods attach directly to the hose, but you'll need a bucket of hot water to get the hose onto them. The blast gates apparently attach directly to the PVC pipe, male from the blast gate into the pipe. I bought metal blast gates, as I think they'll last longer with the abrasive grain dust.

This is an on-going experiment. I haven't found anyone else--though I'm sure they're out there--using a system like this in their mill room. The biggest upside--aside from increased safety and less time spent cleaning the mill room--is that it eliminates (hopefully) the need for the half-face respirators with dust filter canisters we've been using and the associated costs of training, physical and respiratory evaluation, (I'd never realized how sinisterly dangerous a respirator mask was (rating, apparently, just below an atomic fission reactor in hazard)), fit testing... etc.

I'll let you know how well this works out when I actually get it up and running--I hope next week.

Oh, yeah, as for mounting the collector on the roof: you'll need more suction to overcome the vertical lift, and keep in mind you'll probably be emptying the dust collector daily or more often. A cyclone-style "pre-collector" in the mill room might save you many trips to the roof--if OSHA is OK with it.

[TGTimm]

Eureka!!

Finally got the dust collection system installed and tested, and IT WORKS!

We're using a Jet brand 1 hp, 650 cfm 15 micron bag collector, cost ~$260, installed in a shed abutting the millroom.

We ran ~20' total of 4" sch 20 PVC irrigation pipe, using 45s and 45Ys, avoiding any tight bends, to as close as possible to the top of the mill and the grain weigh bin. I used very short runs of flexible hose to mate the collection hoods to the pipes. I also installed blast gates at the hoods, but I'm not using them so they'll go (two aluminum 4" blast gates available cheap!). Everything is carefully grounded.

I used a "Big Gulp" dust collection hood over the mill, with the delivery pipe from the Flex-Auger through a cut-out in the hood. I sealed the hood to the 32"X32" opening of the bin with clear vinyl storm-window plastic (the grain bin is on load cells for grain weighing, and I didn't want anything to impede its motion), with an 12" X 32" flip-up panel in front for adding minor grains.

I sealed the top of the mill pretty well, and attached an 14" X 8" "Little Gulp" dust collection hood.

I left both hood areas pretty leaky to ensure good airflow.

It's just plain amazing to be able to breath and see in the mill room while a grind is going on! I can't see or even taste malt dust in the air anymore.

In addition to making the mill room a pleasant place to work, much easier to clean, and just much safer, we have eliminated any need to issue respirator-style dust masks to our employees. If you haven't read the OSHA compliance crap for respirators (partial or full face masks with cartridges), it's really scary, very time consuming (training and testing), and very, very expensive. ~$1000 worth of dust collector, materials, and my time to save thousands of dollars annually... no brainer.

PS: The sizes of the various nominal 4" parts are all over the map. These parts, all made for dust collection systems, and, supposedly, compatible with 4" sch 20 PVC irrigation/sewage pipe, all have weird sizes. None of the "dust collection system" fittings I purchased fit well enough to glue up with PVC glue, not even the extra-thick stuff. Some fit inside the pipe, 'though poorly, some slip over, also poorly, some just don't fit anywhere without modification (those 4" blast gates required numerous wraps of electrician's tape to fit tight inside the pipe). The worst were the fittings that are supposed to mate the spiral-corrugated flex hose to the pipe. The pipe end fits loosely--too loosely to glue--inside the pipe. The end that's meant to fit into the hose is threaded to match the hose--or so it appeared until I tried to fit one. The hose has a clockwise (right-handed) spiral, but the fitting's is counter-clockwise (left-handed)! We had to grind the threading off the fittings to get the hose to fit on. Very confusing and rather irritating.

[CMorrissy_]

Timm,

It sounds like a pretty solid operation?

How big is your collection bag and how much malt do you mill per batch and how many batches per day? I am trying to figure out what size collector we will need so that we aren't emptying the bag more than weekly.

Campbell Morrissy

[TGTimm]

Campbell--

It's truly surprising how little dust is accumulating in the collector, considering how much of a mess it made in the mill room. After a week of brewing (I'll have to ask the Head Brewer how much we milled, but I think it is in the 1,200 lb/batch, 14 -20 batches range), there is a couple of lb.s of dust and chaff in the collection bag (I'd guess the bag is about 15-20 gal.).

The dust we are collecting is all pre-mill. I sealed the lower part of the mill and do not collect dust there, as the HB was worried that we would attenuate the pre-weighed grind too much by collecting post-mill.

I think you may want a larger collection bag/canister for the amount of grain you're milling, and with the collector on the roof. For our purposes, the 650 cfm sucker is perfect, but going to a larger collection device will probably mean a higher suction collector, and it will probably be 220V, maybe 3-phase. Ours, at 1 hp, is about the largest I could find that still runs off 110V. I still need to get it wired to turn on automatically--right now, it's a switch on the wall and our brewers sometimes forget to turn it on.

One thing you might want to look into is a separate pre-collector. These are cyclone-style dust separators, meant to be plumbed in-line with the dust collector. I think you could get away with having one of these in your mill room, as it is not a powered device. It would keep you from having to climb up on the roof as often.

This has been and still is an interesting experiment, as I don't know anyone else using a wood-shop dust collection system for their mill. Seems like a no-brainer to me, but... in other words, your mileage may vary.