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Filter dust without losing heat?

Started by Brad_bb, October 18, 2018, 12:56:01 PM

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Brad_bb

I need to plan a dust collection system for a new shop.  The sawmill will be inside and I want to collect the dust to keep the shop clean.  The shop will be heated in winter.  Can you filter the dust without sending it outside where you'd lose all your heat?  If so, where do I look for equipment to do so?  Blowers aren't the issue, but filtering that much dust is.

Note, the mill will be electric, and I'd like to have the dust collection activated by the switch on the mill.  Other devices will also be connected to the dust collection like a planer, table saw etc and hopefully dust collection will be relay activated by switching on those machines.  I could also opt for a smaller dust collector blower if needed for the smaller machines.
Anything someone can design, I can sure figure out how to fix!
If I say it\\\\\\\'s going to take so long, multiply that by at least 3!

charles mann

Use a flex pipe that connects directly to the dust shoot on the mill and pipe it to an outside collection silo with, if you want, a bag at the bottom. It'll limit the need for numerous filters and filter change times. 
Temple, Tx
Fire Fighting and Heavy Lift Helicopter Mech
Helicopter and Fixed Wing Pilot

Brad_bb

But isn't that pumping heat directly outside and pulling cold air inside?
Anything someone can design, I can sure figure out how to fix!
If I say it\\\\\\\'s going to take so long, multiply that by at least 3!

charles mann

You think it would pull that much heat out during use? If it would be pulling cold air in, maybe sealing off the shop would be the first place to start. 
Temple, Tx
Fire Fighting and Heavy Lift Helicopter Mech
Helicopter and Fixed Wing Pilot

Southside

What is your budget?  Grizzly has mulit bag type collectors that have HEPA filter systems on the exhaust so your heat would stay in the shop and the dust in the bag.  
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SawyerTed

When I was purchasing equipment for school woodworking shops, I purchased a number of bag style dust/chip collectors that we installed inside.  We also installed some cyclone types inside using a drum to catch chips and dust. I usually had to put them out for bids so I don't recall all the vendors but Baileigh was one. 

For the school shops we had various machines including planers attached.  I suspect in a production environment the frequency for emptying the bags or barrels would be a consideration.
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alan gage

Keeping it all inside seems like probably the cheapest and easiest but I'm not sure how feasible that is depending on shop size. I've seen some pretty big units with 3 or more what appear to be 55 gallon drums daisy chained together. That would give some capacity. Or maybe even just one 55 gallon drum would do if it was quick and easy to swap out drums. Then you could just empty once at the end of the day (or multiple days depending on use) Fairly large scale dust collection systems seem to go pretty cheap on craigslist/facebook marketplace.

Another option would be a cyclone unit outside with the exhaust plumbed back into the shop with a filter to catch the fine particles the cyclone missed. But unless you've got a really big hopper outside, like the commercial guys do, it seems like it would be easier to keep it all inside rather than going outside to empty barrels all the time.

My vote would be for keeping everything inside. I've got a large 3hp Oneida and never thought it was excessively noisy. A cabinetmaker friend upgraded to at least a 5hp 3 phase (maybe 7.5hp) Oneida and it's all inside too. Noise doesn't seem so bad considering the other equipment that's being run.

Alan
Timberking B-16, a few chainsaws from small to large, and a Bobcat 873 Skidloader.

alan gage

Quote from: charles mann on October 18, 2018, 02:45:05 PM
You think it would pull that much heat out during use? If it would be pulling cold air in, maybe sealing off the shop would be the first place to start.
If air is leaving the shop the same amount of air has to be pulled in to replace it. Sealing the shop to that point would only hamper the effectiveness of the dust collection.
Alan
Timberking B-16, a few chainsaws from small to large, and a Bobcat 873 Skidloader.

Hilltop366

My first thought is to have a indoor dust collection system but use a large bin(s) with removable top that could be moved with a forklift for emptying and air return filter but probably by the time you empty it and clean the filters there would be more mess in the shop than you would like and lots of heat loss from opening the door to remove and return the bin plus a loss of floor space in the shop.

Second thought would be to put the dust collection system outside the shop perhaps in shed and still use the large bin(s) for a larger capacity with the filtered return air running back to the shop or try to figure out if it is feasible to run the return air through a heat exchanger.

Satamax

Quote from: Brad_bb on October 18, 2018, 12:56:01 PM
I need to plan a dust collection system for a new shop.  The sawmill will be inside and I want to collect the dust to keep the shop clean.  The shop will be heated in winter.  Can you filter the dust without sending it outside where you'd lose all your heat?  If so, where do I look for equipment to do so?  Blowers aren't the issue, but filtering that much dust is.

Note, the mill will be electric, and I'd like to have the dust collection activated by the switch on the mill.  Other devices will also be connected to the dust collection like a planer, table saw etc and hopefully dust collection will be relay activated by switching on those machines.  I could also opt for a smaller dust collector blower if needed for the smaller machines.
It is absolutely doable.   
Please read this
Dust Collection Research - Home
I made my own 2.2 kw cyclone. 
A bit small for my shop now. But plans are in the pipe. 
I stopped coughing as much, with the filters on this one. 
Grizzly offers some nice cyclones.  Tho, you will need a big one with a sawmill.  And they're not cheap. 
One word of advice i can give, if you can afford it, buy a rotary vane, which will allow you to use a bin, garbage container, trailer or whatever under the cyclone. 
French CD4 sawmill. Latil TL 73. Self moving hydraulic crane. Iveco daily 4x4 lwb dead as of 06/2020. Replaced by a Brimont TL80 CSA.

alan gage

My Oneida has a large pleated filter (about 5' tall) for the exhaust air. It's amazing how little dust actually makes it into that filter. It has a little catch bin that unfastens from the bottom to empty the dust. I bang on the sides of the filter to knock dust loose before I empty the bin. Every so often I'll blow compressed air through the pleats before emptying the little bin too. You can also rinse it off with water.

I would think that with the larger chips coming from the sawmill and planer (as opposed to table saw, chop saw, and sanders) that very much of anything would make it past a good cyclone.

Alan
Timberking B-16, a few chainsaws from small to large, and a Bobcat 873 Skidloader.

charles mann

Quote from: alan gage on October 18, 2018, 05:03:21 PM
Quote from: charles mann on October 18, 2018, 02:45:05 PM
You think it would pull that much heat out during use? If it would be pulling cold air in, maybe sealing off the shop would be the first place to start.
If air is leaving the shop the same amount of air has to be pulled in to replace it. Sealing the shop to that point would only hamper the effectiveness of the dust collection.
Alan
Yes, i know. 
Its a trade off somewhere. Inside, the collection unit will keep heat in, but would require a good filtration system. Its doable, but the amount of heat being lost, shouldnt be that much. 
We have 3 3tn dust collectors throughout our shop, especially in the grinding room and sheet metal bays. The units are outside and our shop stays a nice 70F, hotter when on top of the acft, and the heater units cycle on and off. We dont loose a lot heat, unless the hanger door is opened and we have 6 4" pipes for fresh air vents. 
Temple, Tx
Fire Fighting and Heavy Lift Helicopter Mech
Helicopter and Fixed Wing Pilot

Den-Den

A cyclone with filter will do it as mentioned above.  I suggest that you put in a way to divert the air either through a filter inside or directly outside.  The equipment will generate quite a bit of heat and in warm weather it will be nice to vent outside.
You may think that you can or may think you can't; either way, you are right.

Brad_bb

The new shop is 36'x53', same as the current shop.  In the current shop, I have a 1.5hp Jet blower that is use only for my beam planer chips, blowing it from the shop out the wall into the next room into a 4'x4'x8'long box.  When we're planing beams now continuously, the box will be full in 1.25 to 1.5 days.  Running continuously, when we are doing a lot of beams, It will suck significant heat out of the shop.  This is only 1100cfm.  I'm currently not using this set up for mill dust because I know it will fill that room with fine dust as the box just has vent holes around the top of the sides.

I'm assuming I'll need a higher hp blower for the new set up as I will have the have the blower/collector on the opposite side of the room (an additional 36 feet).  I also know that the very fine dust produced by the mill, especially when milling Ash because it's so dry, will clog filters quickly.  This means I would need significant fiter area.  I'm hoping that they don't need to be changed/cleaned too often.  Also this will not be a production shop.  More of a hobby/mild production.  Right now I'm milling a lot for buildings I am going to build, so I'm going full bore.  After I'm done with all that, I plan to do some RRQS'ing for fun, furniture and project wood, etc. and maybe I'll produce some live edge brace stock for others if I can determine there's some market for it.  That is pretty light duty work - two cuts per brace and then plane.  I'll go from milling 4 days a week down to probably 1 day a week or less.  I'll do more woodworking than I do now. All of those machines will require dust collection, but that demand will be much less than the sawmill and beam planer.  I will get an industrial planer too for surfacing my rough sawn lumber.  

I mean, a 5hp blower may be adequate, but the real question is the filtration?  How big of a system do I need?  Where do I go to consult on this?  How much dust bin capacity will I have?  I want to be able to run a full day of planing before having to empty the bin/bins.  PLaning chip volume will be about 100 cu ft a day.  Milling dust will only be about 10cu feet, but will fill the fine filters far more quickly.
Anything someone can design, I can sure figure out how to fix!
If I say it\\\\\\\'s going to take so long, multiply that by at least 3!

tmbrcruiser

I have tackled the problem you are concerned with. My shop is 32' x 60' and has a Weinig 5 spindle moulder requiring 5,000 cfm to operate. The shop being heated and having air conditioning I could not vent outside. The solution was pricey but you may not need 5,000 cfm and smaller units are available. My choice was a Laguna X Flux:10 (10 hp, 3 phase) has 3-54 gallon tubs for dust, auto reverse, 3 cartridge filter and a silencer on the air return. Check out Laguna they may have what you are looking for. Good luck!
Once you get sap in your veins, you will always have sawdust in your pockets.

firefighter ontheside

I vent outside, which is not a huge issue with using shop tools that are usually only on for a few minutes at a time.  With the amount of time a sawmill will be running, the heat loss will be significant.  I can feel the temperature change even in my shop.  In the summer when my AC is on, I really feel the humidity coming in. I don't really think it's a viable option for a sawmill.
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Don P

The first couple of production shops I worked in had cyclones outside with no return air, frigid in winter. We had to keep a door open for return air. I forgot one night and had all the doors closed and the dust system running. I went to a door and couldn't open it, I felt lucky it didn't buckle any of the big doors. 

I then went to a shop that had bag houses outside on the exhaust of the cyclones. They had multiple vertical bags in 2 banks and would run one bank while shaking and reverse blowing the other set. The warm filtered air then returned inside, warmest 8 winters of my adult life :D. There are a number of ways they configure these and in different sizes. More production oriented, google baghouse or bag house, might be some ideas to borrow from those.

Fire is also a concern. You have lots of draft and combustible dust, keep an extinguisher handy and if one starts in the tubes shoot it into the offending intake. The shop manager put out one from the wide belt that way and it stuck with me. Later that high turnover shop burned a dust truck, same scenario but it had had complete employee turnover in the 2 or 3 years between events, the dust truck even had a dump, multiple ways of solving the problem, they panicked and missed them all. If you are returning air to the shop that becomes more critical. All the furniture plants nearby have had dust system fires. They are large systems with in line fire detection, inspection/firefighting ports and in plant fire trained personnel, the fire department is also well drilled on how to fight fires in those systems. A number of folks here are scaling dust systems up keep that in mind too.

Satamax

Brad, i have 1300cfm, and 600 sqft of filter approximately. Filters are Donaldson ultra web. And i need to clean twice a year. 









You can see the filters kind of all right there. 

French CD4 sawmill. Latil TL 73. Self moving hydraulic crane. Iveco daily 4x4 lwb dead as of 06/2020. Replaced by a Brimont TL80 CSA.

btulloh

Quote from: Satamax on October 18, 2018, 05:15:35 PMIt is absolutely doable.    Please read this Dust Collection Research - Home I made my own 2.2 kw cyclone. 


I read through a fair amount of this.  There's a lot of information there.  Sort of overwhelming.

Brad - good luck with this.  It'll be interesting to see what you come up with.  Everybody has particular criteria they want to meet with a collector system and it's never easy to come up with solutions.  I'm sure you'll come up with something good.

One thing for sure is that the collection end has to be part of the indoor air even if it's a little enclosed space outside the shop or you'll dump all your heat outside in no time flat.  I went through that.  Somehow you've got to return the air and if it's cold air, your inside temp will go down in a hurry.  Returning the air without bringing back fine dust is not easy but can be done.  The best thing I've seen is to use some pre-filters on the return made from the cheap mesh filters used in HVAC systems.  Then maybe something after that for finer dust.  Requires a bit of regular service.  

Keep us posted on your design.  I'm always looking for ways to improve my system.

HM126

ButchC

A couple years ago when I was looking to do the same thing I was lead away from the home shop type dust collector units by a fellow who runs a cabinet shop. He said enough fine dust escapes them to cause problems in a clean shop or one were finishing is done. Since  my wood working tools share the same shop with my machine tools I kinda needed  a good system that didnt exhaust the air for same reasons as you. Picture is what I purchased made by Dust vent. Its a small sized industrial bag house, as far as I can tell it keeps my shop nearly 100% wood dust free. Just run the bag knocker now and then and clean the pan.  I do have a cyclone in front of it to collect the coarse stuff.  It actually sits above the shop on the scent floor and I piped the exhaust back to the shop area with standard ducting. I paid $100 for mine at a used tool dealer. There is a place in Cleveland that always has a few around for cheap. Be glad to take some pics of my installation if you wish.


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mike_belben

I was a maintenance mechanic/welder at smith and wesson.  52 acre building, hundreds of torit dust collectors with mostly donaldson filters. Everything from smoke to lead to sawdust to paint fumes.  
Praise The Lord

Brad_bb

Thanks everyone for the responses so far...

Mike_belden, that is the one company I came across on youtube.  I'll have to call them and see what kind of advise they can give.  

ButchC, that unit doesn't look very big.  I would assuming you'd need a lot more filter area than fits in that cabinet for mill dust?

tmbrcruiser, I just checked out the Laguna collectors.  One of those like the 5hp might work for the mill, tablesaw, bandsaw, and maybe a little lunchbox planer.  The problem comes in with my beam planer and an industrial planer when I'm planing  beams or S2S a lift(stack) of lumber all at once.  Those small cans are too small capacity.  I'd fill that in 30 minutes and that's too short a time to have to empty it.

I need a big capacity for chips- at least a minimum of three 55 gallon cans I'd say.  I do not want to have to manually shack or knock a fine filter, automatic is needed.  
I'd like to be able to plane for  a 6 hour day with only needing to dump chips etc at the end of the day, not multiple times a day.  
Anything someone can design, I can sure figure out how to fix!
If I say it\\\\\\\'s going to take so long, multiply that by at least 3!

alan gage

Quote from: Brad_bb on October 19, 2018, 03:48:10 PMI do not want to have to manually shack or knock a fine filter, automatic is needed.


Even if it's only once/week or less?
Timberking B-16, a few chainsaws from small to large, and a Bobcat 873 Skidloader.

Satamax

Brad, what i was saying about a rotary vane.  Or rotary airlock.  You have your cyclone, and this "airlock" bellow. With an airtight box, or open to the outside, with a container of some type, or even a trailer. 

I also have seen airlocks like this, which are like roots compressors, and compact shavings and sawdust. The later one, with a conveyor belt which was throwing the compacted "chips" into a large silo. (is that the right word for the big containers where you usually store grain? ) 

The second cyclone shown by Alan Gage, could be retrofitted with proper filters. 
French CD4 sawmill. Latil TL 73. Self moving hydraulic crane. Iveco daily 4x4 lwb dead as of 06/2020. Replaced by a Brimont TL80 CSA.

Brad_bb

Satamax, do you have any pictures of what your talking about.  I know what a helical or rotary screw air compressor is, but now sure what you are talking about?
Anything someone can design, I can sure figure out how to fix!
If I say it\\\\\\\'s going to take so long, multiply that by at least 3!

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