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Suitability of plastic dust barrels4/27
I've got an old Torit 7-1/2 Hp cyclone I'm trying to adapt to a new shop. Since the collection barrel will be under negative pressure in this system, I wonder whether the seemingly-flimsy plastic drums so common these days will resist collapse from the system's vacuum.
Can any of you share first-hand experience?
I'm not sure how flimsy your plastic barrels are. Generally they are actually pretty stout due to thickness and ribs that are part of the molding process. When you think about the fact that they are designed to transport bulk products and must withstand a certain level of abuse (most warehouse are not known for handling deliveries with kid gloves). Also think about that if you were to use a plastic bag/liner that generally a 6 mil bag is the recommendation with something to keep the bag from being sucked back into the machine. In my Oneida system I am using and reusing 4 mil bags with out any issues (5 hp/1900CFM @ 6" static pressure). Perhaps the vacuum is not as significant as you think? I have also seen where fiberboard drums are supplied for use in dust collectors. I think that they are even flimsier then plastic drums. All of this is just food for thought and comparison. Hope that this helps.
I'm not sure how flimsy your plastic barrels are. Generally they are actually pretty stout due to thickness and ribs that are part of the molding process. When you think about the fact that they are designed to transport bulk products and must withstand a certain level of abuse (most warehouse workers are not known for handling deliveries with kid gloves). Also think about that if you were to use a plastic bag/liner that generally a 6 mil bag is the recommendation with something to keep the bag from being sucked back into the machine. In my Oneida system I am using and reusing 4 mil bags with out any issues (5 hp/1900CFM @ 6" static pressure). Perhaps the vacuum is not as significant as you think? I have also seen where fiberboard drums are supplied for use in dust collectors. I think that they are even flimsier then plastic drums. All of this is just food for thought and comparison. Hope that this helps.
I'm encouraged by your remarks though on Pentz's site (I think that's where) there were cautions against trying to use thin wall stovepipe for duct because of the possibility the vacuum would collapse it. Of course snap-lock pipe does frequently end up out of round.
Does anyone else have first hand experience collapsing anything with dust collector vacuum?
Mark, I know you thru RMTC. I will call you later today to continue this discussion. There is much to cover, phone is faster then type. If that is okay with you.
I don't know about the stoutness of the plastic barrels, but I don't think there is the same vacuum in the barrel as is in the pipes? I use 2.5 mil bags in the same 7-1/2 hp Torit and they don't go anywhere.
I was talking with the guy that designed my system a couple years ago and he was telling me about one of his projects. They had just installed all the ductwork in a large factory, IIRC a 24" main line! Anyway they finished up and planned on testing after lunch. When they came back and fired it up..... it collapsed the 24" duct work! Apparently some supervisor who thought he knew something came in and closed all the gates while the guys were at lunch. Apparently thought it would work better that way??? When they came back they didn't think to double check and the result was having to replace all the ducting that had just been installed! This was spiral pipe of course which is much more robust than stove pipe! So if you have a big enough collector you certainly can collapse your ductwork;>)
I've been using plastic barrels for years.
I found out the hard way, regular lightweight duct pipe doesn't work in neg pressure, especially larger diameter.
The only real issues about the suitability of using plastic barrels for dust collection is that you can't use plastic bags/liners since most plastic barrels are tapered at the top and bottom. You can't get the full bag of sawdust out of them. If you don't bag sawdust then they would work just fine.
Big K invited me to his shop to talk about the specifics of good dust collection. In a whirlwind visit, I learned that none of the commonly available receptacles will collapse under collection-levels of vacuum though the choice of barrels still matters.
If you're selecting barrels for a revised assembly of dust collection parts, you'll want barrels whose lid retainer rings are lever action and operate outside the rim rather than within it. That way the flex hose installation in the lid won't interfere with the operation of the lever.
Similarly, if you have the option, choose barrels whose lids have a flat center section rather than bungs. Bungs will probably have to be cut out and a flat patch installed in order to mount the flex hose adaptor.
Despite the easy availability and seemingly eternal lifespan of plastic barrels, fiberboard may be a better choice. They come in a variety of sizes and proportions. New or used, they're cheaper. But most importantly, fiber barrels have cylindrical walls so plastic-bag liners are easily removed when the drum is filled.
I'm confused about your referring to the barrel lids, aren't you using the one supplied with the cyclone? Mine has no clamps or other devices to secure the barrel, it simply sits on top.
Another thing I thought might be a problem with plastic barrels is static build up? I keep my metal barrel grounded to minimize the static, I'm guessing a plastic barrel would build up static?
Well, Jeff, this post and a couple of others originally sought advice bringing together components bought at auction... po' boy stuff but interesting and kind of fun.
I can see how a complete manufactured cyclone set up could do away with the need for clamps.
My first system, used for about 30 years, was a positive-pressure, filter-bag affair, a tremendous improvement from shoveling dust and shavings after the fact.
In that system, also home made, to secure ordinary steel 55 gallon drums under the bag house I had a canvas shop sew up Naugahyde sleeves the diameter of the drums but with a piece of bungee cord hemmed into the bottom. In use, I'd stretch the sleeves around the outside of the barrels to effect a seal. The top edge of the sleeves were folded back, silicone caulked, and stapled to the top side of 24" diameter holes sawn into a solid core door that made up the plenum's bottom surface.
If the sole purpose of dust collection is to avoid shoveling wood waste, it could be described as successful.
Ok got it, if you need any info on the way your cyclone was originally setup let me know. I'm assuming yours does not have the drum cover with it? Sometimes it can be simpler/cheaper just replacing a missing part or two rather than re-inventing the wheel;>)
If your cyclone is on the original stand I would at least call and find out how much a replacement cover would cost. The way they work is simply a spring fit created by the tube that connects the bottom of the cyclone to the drum cover.....speaking of which I need to replace mine soon as well! I think I have about 3 rolls of electrical tape on it by now to keep it together....po' boy fix;>)
I didn't realize your cyclone is a Torit, too.
Mine came from a factory gone broke in Chicago and was basically junk, too buried and too cumbersome to remove until after the factory was cleaned out. It was stripped of it's bags and barrel, one leg is still bent and it had been pushed off into a dark corner where it sat so long the grease in the bearings stiffened and the motor would not start.
The motor shop cleaned it and put in fresh bearings. Now the motor works flawlessly.
I'll contact Torit about this equipment. After my experiences with Tannewitz and Powermatic, dealing with the manufacturer hadn't entered my mind. I'd be surprised if this cyclone is less than 40 years old.
I'm not sure I understand your explanation of the connection between the outlet of the cone and the drum. Is it a piece of flex tube the diameter of the drum? the outlet of the cone on mine is 7". Maybe Torit has pictures available of more modern designs.
Thank you for your comments.
Yup, I have a newer 7-1/2 hp Torit model 24cyc. I don't think mine's more than 20 years old at most, but the design is probably pretty much the same.
The bottom of the cyclone connects to the drum via the flexible hose, which is also spring loaded. It has enough downward force to keep the drum sealed. Once the collector comes up to speed the vacuum draws the seal even tighter.
You can see mine's been....well....helped along a bit with the electrical tape. The repeated emptying over the years has worn the original rubber out pretty much completely. So I imagine they should have at least that part as a stock replacement item. The lid itself is pretty much just a flat sheet of steel with a small maybe 1-1/2" tall or so rim and a foam rubber type of gasket around the bottom. Oh and you can also see my high tech solution for a removable ground strap.....a length of wire held on by a magnet:>)
hope this helps!
Shoot! That design is great. I'll have to find out if my unit is adaptable to that hardware. It is enough to make me consider going back to steel 55s... or search for a source of extensible-spring flex hose - anyone know what that stuff is properly called? - so I can pirate a great idea. Po' boy land pirates, that's what we be. Aaargh!
Have I been risking a spark-triggered explosion all these years? I never grounded anything and never noticed any static except when I used a steel tube as a pickup on the end of a presumably non-conducting flexible dust hose.
Someone asked earlier about grounding plastic barrels, maybe it was you, Jeff, but the significance of the question escaped me at the time. Maybe the reason I've never had any static related trouble is that nothing was conductive after the waste-laden air exited the blower. Is that possible?
Fire & electrical regulations and inspections are enough to make a mild fellow want a fist fight... but then, consider recent events in low-reg/ low inspection Texas.
I use the ground b/c I was constantly getting zapped when pulling the plastic liners out! I'm not sure there's any real safety threat? In New England it gets pretty dry in the winter and static builds quick....the worst is mdf dust, that stuff creates static darn near instantly! All the dust spinning around in the cyclone does create static so for me it was an easy no cost fix;>)
Hi David, I've heard other guys drop in a shovel of dust first??? I drop the bags in empty and go. As long as the drum is airtight the bags stay put. But you do need an airtight drum!
Here's a little side story on how I learned the hard way.....when I first got my system up and running I found pulling full bags out of the drum tricky. There would be a bit of vacuum created by the full bag in the drum. In my infinite wisdom I decided to drill a couple holes in the bottom of the barrel to alleviate this suction. First time I started the collector after drilling the holes it sucked the plastic bag right up through the impeller! So I patched those holes right up and now just deal with the suction;>)
I've never heard anything about using a hose? The cyclone sits on top of the barrel so is already connected, not sure where the hose would go or what it would do?
I have a couple 30 gal barrels from the fertilizer company up the street. I'm running a cyclone on top one and a heavy duty rubber trash can type collector on the 3 horse with no threat of collapsing.
Under the two the three upper bags are just clear plastic bags and they don't collapse on mine or other, similar systems.
Thanks for your input and photo. It brought to mind another question about the location of the window in your barrel: I've resisted the impulse to install my windows until I have a good sense of what level of fill I need to see as a warning to change out the barrels. Would you recommend installing the window in the upper third of the barrel's height? Obviously it would be trickier to do that and require a thicker caulk joint. Of course the impeller of my unit sits at least 5' above the top of the barrel so maybe the swirl of the conical separator will be less turbulent in my setup.
I wouldn't have problem with a couple view holes. One high and one low. I just didn't feel it was needed in my application, since I'd rather empty it before I have to wrestle a full drum.
I heated my acrylic so it would flex to the shape of the barrel.
I have no idea of how high the level would have to get before the cyclone would start pulling from it. However, I managed to pull it over a couple times when it only had a few inches of sawdust and little or nothing got pulled through the impeller into the clear bag.
On my cyclone it will pull once the drop hose gets plugged. Sometimes it's blocked b/c the barrel is full, or sometimes if I'm hogging a lot of material on the planer it can block it up as well. Either way it's a real PITA trying to empty the filter bags. If the RAL's weren't so darn expensive I'd install one and be done with it.
I am curious if you have any static issues with your plastic drum? I get a LOT of static with my metal drum in the winter if I don't keep it grounded. I would guess plastic would be even worse?
I can't breath in my house without starting a personal lightning storm. Interestingly, I touch the stainless faucet and nothing happens, until I stick my finger in the water, THEN I discharge. In another scenario, I touch the hinge plate on my doors and take results in a discharge too. Hmm, two humidifiers (one up stairs and one down) isn't enough.
In spite of these humidity conditions, I note no problems, whatsoever, in my shop. That may be because I'm on concrete floors. There is a bit of cling in the plastic bags under either of the collectors, but that seems the norm throughout the year.