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Pneumatic Vacuum System for Efficient Milling Dust Collection
Has anyone created a mill dust collection system using a pneumatic vacuum?
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17 Replies
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I used to own a wood shop. We picked up one of the 2hp dust extractors for cheap at harbor freight. Works pretty good and dumps the dust into a removable plastic bag via cyclonic action.
Might work well for milling operations if kept clean and moisture free.
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I used an industrial vacuum cleaner to remove dust from the outlet that would have otherwise drifted into the surrounds
It had some type of filter shaker that operated when the filters started to block
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What about the need for explosion proofing?
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What are you trying to comply with? ATEX for the distillery area or reducing explosion hazard due to dust?
the vacuum itself is the hazard reduction for dust explosions.
As for ATEX in distillery it would seem to be easier to remove grain processing from the distillery area thus eliminating ATEX compliance on motors and electrical. I’m not an expert on ATEX compliance. Fiji has no rules for this so we are left to common sense when implementing safety measures.
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We’re not trying to comply with anything but, as you put it, common sense. Trying to remove grain dust for overall cleanliness and reduce/remove any potential explosion hazards created by our milling process.
Since posting this to the forum, I was educated by a grain dust removal expert – he specs dust removal systems to granaries. The main factor when sizing a dust collection system is to keep your CFM at or above 4,000 CFM so particles don’t fall out of the air stream, use metal ducting (6″-8″) and if flex hose is needed make sure it has a metal wire in it to dissipate and static build up.
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a properly built (sealed up) mill and auger system will generate very little dust. If you are building a big operation you will need dust collection but most smaller systems generate very little dust
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Golden Beaver Distillery said “Has anyone created a mill dust collection system using a pneumatic vacuum?”
Grain dust itself is extremely explosive and many people have died from grain dust explosions. If I were moveing grain dust with blowers or similar mechanical equipment, that equipment would have to meet the explosion proof requirements for moving grain dust. This equipment is very common and not that much more expensive. Also you must mitigate the possibility of static build up and static charge release with proper grounding. Grain dust being sucked or blown through piping creates large amoiunts of static. I have worked with blowers and blower piping for over 20 years and currently design explosion proof blower systems for moving large amounts of hogged up hemp which has around 4% residual ethanol which makes it very explosive. Keep in mind that all bearings must be lubricated regularly. If a bearing fails in your blower, ignition and explosion can occur. The fan and other mechanical parts must be inspected and maintained on a regular schedule. Be safe and get the proper equipment for the job. Don’t take unnecessary risks by using equipment that is not safe for the job.
I’m sure that you are all about safety and that you will do the right thing as long as you have the information and knowledge concerning how to do that. It sounds like you have sought out and found a professional so you are on the right track and I know that at this point you probably understand how hazardous dust can be, however it never hurts to hear it all again,
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The reason I posted the question is that the pneumatic vacuums avoid all issues with heat and bearings. Just wondering if a system (blower, duct work and intakes) has been built using a pneumatic vacuum?
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Hence using a pneumatic vacuum and duct work to build a small collection system.
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Most systems that utilize blowers have the blowers on the suction side so that vacuum is used to move things. In those systems you must maintaine the bearings on the fan shafts or when the bearings start to fail, the fan will go out of balance and hit the housing causing sparking and possible ignition.
Pneumatic vacuums for grain dust removal sound interesting. How do they work? 4,000 cfm is huge. How do you get that without a fan on a shaft?
Depending on your circumstances, CptnKB’s solution with the auger is probably the best. If everything is tight, an auger connected to your mill should not produce enough dust to cause you a problem, they don’t cost that much and they are easy to set up.
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Resources:
https://law.resource.org/pub/us/cfr/ibr/001/acgih.manual.1998.pdf
https://billpentz.com/woodworking/cyclone/ducting.cfm
FPM tends to be more critical with respect to system design. Say you need at least 2500 ideally. The pneumatic vacuums I am looking at would be under rated for this kind of duty, and also are warned not to be used with combustible dust. I also expect they take some serious SCFM to run. Dust collection is usually done with cyclonic units or otherwise high CFM, High Static Pressure fans that exhaust to outdoors.
TABLE 3-2. Range of Minimum Duct Design Velocities Nature of Contaminant Examples Vapors, gases, smoke All vapors, gases, and smoke Fumes Welding Cotton lint, wood flour, litho powder Local Exhaust Hoods 3-19 Design Velocity Any desired velocity (economic optirnum velocity usually 1000-2000 fpm) Very fine light dust Dry dusts & powders Fine rubber dust, Bakelite molding powder dust, jute lint, cotton dust, shavings (light), soap dust, leather shavings 2000-2500 2500-3000 3000-4000 Average industrial dust Grinding dust, buffing lint (dry), wool jute dust (shaker waste), coffee beans, shoe dust, granite dust, silica flour, general material handling, brick cutting, clay dust, foundry (general), limestone dust, packaging and weighing asbestos dust in textile industries 3500-4000 Heavy dusts Sawdust (heavy and wet), metal turnings, foundry tumbling barrels and shake-out, sand blast dust, wood blocks, hog waste, brass turnings, cast iron boring dust, lead dust 4000-4500 Heavy or moist Lead dusts with srnall chips, moist cernent dust, asbestos chunks frorn transite pipe cutting machines, buffing lint (sticky), quick-lime dust 4500 and up
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And now they need to add hemp to the list👍
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How do they work? You create a venturi using a compressed air source.
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That’s cool. 85 CFM is a lot of air. Just keep in mind that the compressor will be expensive.
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Good compressor and a cascade system of a couple storage tanks would support the vacuum and any pumps you maybe running in your plant. It’s only money…
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85 CFM is a colossal amount of air required as well as the piping required to deliver it.
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This conversation has left the common sense area long ago. Lol. The system being discussed must cost well in excess of $15k!
1: dust is not intrinsically explosive. Only when spreadninto the air and creating a specific air/fuel ratio does it become explosive. Reduce or increase the air fuel ratio and the hazard is greatly reduced.
2: fire/explosions require three things FUEL, AIR, and SOURCE OF IGNITION remove one and again the hazard is reduced
3. A typical wood dust removal system using a 4” rigid pipe (aluminum or steel dryer vent or stove pipe is good and allows grounding ) will pull around 1550 cfm at low low psi and is 2hp that should be adequate for any grinder under about 7-8hp. Let’s think about this logically wood dust is probably hazardous too right?
4: the motor system on the vacuum I link below is typically a TEFC totally enclosed fan cooled motor. With a little attention to your electrical connections you could easily seal off the motor and power supply from being a source of ignition
Central Machinery 2 HP Industrial 5 Micron Dust Collector https://www.amazon.com/dp/B006ZBAGWA/ref=cm_sw_r_cp_api_i_eAsSDbEETH0V5
Ill admit I’m not an expert on grain dust and further I’m certainly not responsible for what goes on in your distillery. But then again I’m not selling anything either
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