dust collecting system installation
TotallyRetired
| Posted in General Discussion on
I am in the process of designing and building a 26â€â„¢ x 28â€â„¢ shop addition to the back of my garage. I would like to install a 2-stage cyclone dust collecting system. Has anyone put the duct-work under the concrete floor to obtain shorter routing? Are there any other disadvantages to this method other than the lack of flexibility of change? I have been collecting stationary equipment and planning for 32 years.
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I've heard of such things. And that they're supposed to be better - for access, performance, etc. However, many times the increase in floor elevation is an issue. How can you handle that?
My plan is to excavate and put the ductwork in the ground. Similar to the way a plumber would install their waistline for sanitary sewer. I would then poor the slab of which I am also planning on embedding tubing for in-floor heat. I have heard that plastic is not recommended and that galvanized 22-gauge ductwork will rust. Has anyone experienced this type of installation? Maybe I should use soil pipe?
That would certainly eliminate the possibility of service if ever needed. Soil pipe? That may eliminate the need for grounding, which PVC would need be. But condensation would be my concern. Sawdust and condensation is known to create granite.
They do make SS dust collector pipe and connectors. Ain't cheep.
I read an article, I think in one of FHB's special shop issues, where someone did use PVC pipe in a concrete floor for dust collection. They recommended installing multiple cleanouts in case something got jammed in there.
edit- I meant FWW, not FHB.
Edited 2/1/2008 4:23 pm ET by Shep
Two great books on the subject.
Controlling dust in the workshop - Rick Peters
Woodshop dust control - Sandor Nagyszalanczy
Two stage great for separating out bigger chunks, but necessitates upping the impeller and air flow to compensate.
Dollar for dollar sewer and drain pipe probably best combo of efficiency and cost, but should have static charge accommodated for by grounding.
In Minnesota me thinks it gets pretty darn cold in the winter, condensation would likely be a worry.
From what I recall no significant efficiency improvements for putting underground, if there's any room for overhead would be most practical.
Let's not confuse the issue with facts!
IIRC from what I have read the issue of static discharge with PVC is really a non-issue. Look up Bill Pentz's site on the net and read what is there for research into the issue.
They can't get your Goat if you don't tell them where it is hidden.
I think I would put the ductwork overhead rather than under a concrete slab. This would eliminate the maintenance issues that could come up with an inaccessable duct system, as well as the flexibility problems that may come up due to adding, elimating, or rearranging tools.
If you're still designing, raising the ceiling to 8'-6" or 9' should be easy enough to allow room for a duct system without using up headroom. While you're at it, try to create a separate room for the DC - they can be noisy. I know that I really hate it when I need to fire up my DC just when Eric Clapton breaks into "Further On Up The Road" - lol
Cast troughs (sp) in the floor and run conventional dust collector piping. That gives you access to system to reconfigure as needed.
Agree 100%, I had entertained that Idea myself.Spheramid Enterprises Architectural Woodworks
"Success is not spontaneous combustion, you have to set yourself on Fire"
Not sure about underfloor. Don't think I would do it - I like the chance to reconfigure, no matter how well I thought I had it planned out before.
I have a system and components designed by Onieda. Can't recommend them highly enough.
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Also consider an air "cleaner", that will create a swirl pattern around your shop and filter the air - it really works -
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Forrest
Edited 2/1/2008 8:06 pm ET by McDesign
Cyclone is in the next room; fan unit and bags are in the attic above that. Only empty the bags once every 6 months or so.
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Forrest
Edited 2/1/2008 8:14 pm ET by McDesign
As pete said, I would worry about the condensation build up in a pipe running through a floor. No way to dry it or drain it on a continuous basis then the saw dust comes through and sticks in the pipe and builds up. Just like I wouldn't run a dryer vent line through a slab for the same reason.
“Some people wonder all their lives if they've made a difference. The Marines don't have that problem.”
Reagan....
Failure is the condiment that gives success its flavor.
-Truman Capote
I did just that and had no trouble at all. I used galvanized extra thickness dust collection duct. All the straight seams were on the top and all the joints were caulked. Each joint was fastened with a single self drilling sheet metal screw in the top only (to prevent snags).
The key, I think, is the ground conditions. In my case the slab was perhaps a foot or so above ground level, and the duct was embedded in the stone which was placed on sand. If you put the duct in regular dirt with poor drainage it might not work so well.
The only burried portion was to the table saw. Everything else was run above the floor. Don't forget to run power for the table saw under the floor as well.
I'd go for it. The worst that could happen is that someday it fails and you abandon it and go above the floor.
I strongly recommend getting a dust collector with a cartridge filter that filters down to a fine micron level. It is the fine dust that gets deepest into the lungs and causes the most damage.
I did it in my last shop. I just ran the ducts to the middle of the (in my case) 3 walls. From there you can go up the wall and put a T in so you can go both ways on the wall. I also ran a duct to the middle of the floor for the tablesaw. While you are running the ductwork to the middle of the floor run 220 and 110 there also.
I used 6" w&d pvc. It is cheaper than schedual 40 pvc. There can be a problem with static build up in plastic pipe so I ran a bare ground wire wrapped around the pipe that connected to each machine and to the dust collector. I put the collector outside of the room so I wouldn't have to listen to it. The combination of the collector in another room and the ductwork under the slab makes for a very quiet system. And there were no pipes around in the room.
If you have any questions let me know. I worked long and hard on my system to get it right. Might as well give you some help.
so I ran a bare ground wire wrapped around the pipe that connected to each machine and to the dust collector.
About that ground wire.
My electrician buddy was not impressed with tieing that wire to the machines.
His take is that we are only draining off static electricity so tie that ground wire to the concrete floor next to the machine.
Reason being, if the machine " faults to ground" ( or something like that) the duct work and any thing else that wire touches could be energized.
I don't completely understand his reasoning, but I do trust the guy.
Just a thought.....
That's a good point. Seriously. Ask him this though. If the ductwork is in the ground then why have a ground wire wrapped around it at all? I went around and around with this stuff when i did it. There was some things that I just didn't get answers too. But there was always someone who had something else to say. But no comprehensive system for everything involved.
Why wrap a ground wire around the ducts at all?
The wire goes inside the PVC duct, not around it.
What's the difference, the static will build up on the outside of the duct just as much as it will the inside.
I don't think it matters either way and I question the need for it at all from what I have read on the subject.
This is exactly my point. People say stuff with no real answers. Who can you name someone that is a static electric build up expert? And has practical application solutions? That's what I thought.
I used to work in a factory building high speed conveyor systems. Most of them were for dvds, vidios, and cds. These little thing would really zipp along on the conveyer and sometimes they would build up a static charge. One time they were doing a wheelie of a transition from one belt to another. They weren't sure so they brought in a high speed camera. Did I say they were going fast? So anyway, they got the little buggers on tape doing wheelies and jamming up the system.
Their solution? They bolted a woven copper strap about an inch wide to the conveyer frame and made ot long enough that it draped on the floor. That's it. No more wheelies.
So why do some plastics build up a static charge? Do they build a charge just sitting there?
From Bill Pentz's site . Link goes to another individuals research. Pentz has done extensive research on on dust collection. http://mywebpages.comcast.net/rodec/woodworking/articles/DC_myths.html Look here for the a bit more on the issue: http://www.billpentz.com/woodworking/cyclone/index.cfm
They can't get your Goat if you don't tell them where it is hidden.
Here is one disadvantage to in-ground ductwork on a cyclone system that nobody has mentioned yet:
The inlet on a cyclone is pretty high up. If all the ducts are in-floor, then the final trunk line has to go vertical up to reach the inlet.
To do that successfully, the airflow has to be at 4000 feet per minute or thereabouts. This means that you always have to have gates open that are equal in area to the area of your final trunk run. If you do not, the velocity at the final run will not be enough to lift the chips.
In an overhead system the same area dynamic exists, but the final trunk run is horizontal, so less velocity is required to move the chips to the cyclone inlet.
For example, you have 5hp system with 8" trunk line. Open a 4" gate and face joint a bunch of stock. The chips will be going 4 times as fast in the 4" line as in the 8" trunk, because the cross sectional area is only a quarter the size. The chips are loafing along. Horizontal loafing beats vertical up loafing any day.
The other reasons are good, too. Overhead makes a lot of sense for a lot of reasons.
Also, if the cyclone is outside with its inlet at a lower level than the buried ducts, then this particular issue does not exist.
Bill
I can let you know soon. After only 20 years of planning, I have built a 28' X 40' shop with PVC in the slab. The building is supposed to be sheetrocked next week, so I haven't used the dust collector system yet. I installed a copper ground wire on the PVC, but read somewhere that it wasn't necessary since it is effectively grounded in the slab. Knowing I wouldn't have a second chance I ran the ground anyway. I also have a quick connect for the ground wire near the blast gate in case I want to ground the flex duct from the machine in use to the PVC pipe.
I put several inlets throughout the shop. The pipes are stubbed up short of the floor level inside a large opening with a cover that is flush with the floor. (Think of the large canister that a water meter would be in underground.) This way, I can remove the flex hose, close the blast gate and cover the opening so there will be no chance of tripping when not in use.
I did build a separate room for the dust collector with filtered vents to allow air passage back into the shop. It will have a remote on-off control for convenience. I can't answer the condensation question yet. The shop has central heat and A/C to keep the humidity somewhat constant which should help. I can't wait to try it out and will be glad to share info when I do.