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Best way to avoid implosion

2K views 15 replies 10 participants last post by  rocklobster 
#1 ·
I recently got my new dust collection system up and running. I have a 2hp PSI blower with a 14" impeller on top of a cyclone that empties into a galvanized 32 gallon trash can underneath. It works great. Maybe too great.

During some test runs I noticed that there was a loud "pop" shortly after the motor shut down. I discovered that it was the trash can popping back into shape. The thing is starting to cave in on the sides and the lid is getting sucked down to the point of inverting.

I haven't run it very long, but I know it will implode this can if I do. I'm not sure if I want to reinforce the can, replace it, or let some air into it.

Reinforce = maybe cut the spokes out of a few different sized bike rims and drop them in to hold the sides out? That wouldn't help the lid, though, even if it worked.

Replace = I would hate to start over but I will if I have to.

Let some air in = (It is sealed up pretty good) Might work but I'd rather not compromise the suction if I can help it.

What would you guys do?
 

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#2 ·
What type of venting do you have that goes into your fine dust filter? My cyclone empties into a cardboard 35 gallon container and has no problems because the pressure is released through the filter and does not build up in the collection bin.
 
#5 ·
This makes no sense to me

What type of venting do you have that goes into your fine dust filter? My cyclone empties into a cardboard 35 gallon container and has no problems because the pressure is released through the filter and does not build up in the collection bin.
Unless I don't understand how this system works there should be no vacuum in the dust container below the cyclone, for the reason stated above. Implosion, the sucking down and caving in of the galvanized barrel, should not be an issue. How about a diagram or photo of the system layout and assembly to help us understand? :blink: bill
 
#9 ·
Mine is about the same setup, only 1.5 hp but I can still here the can in the other room "Pop" when I turn it on and off. I have not had it implode yet. Until it does I would just use it. I think what you hearing is the can adjusting, but don't think it is actually going to suck up like a tin can. Just my two cents, I say use it, as it fills up it will have less stress on the walls. I just use the "Popping" sound as an indicator that the DC works..........:icon_smile:


When the can is empty the flex pipe will actually lift the can off the floor till there is enough weight in it to keep it down. I can say if there is a vacuum leak in your system the can will not do that, so its a pretty good indication if there is a leak in the system.
 
#11 ·
Mine is about the same setup, only 1.5 hp but I can still here the can in the other room "Pop" when I turn it on and off. I have not had it implode yet. Until it does I would just use it.
Nate,

You've given me an idea. I'm going to close all the gates and see if I can crush the can. :devil2: If it doesn't implode, cool, it stays. If it does, oh well, I need a new one anyway and it ought to make for a good picture.

I'll be back in an hour or so to let everyone know how it went.

Rob
 
#10 · (Edited)
#12 ·
Well, I didn't die, but I did wear my hard hat just in case. I had only turned the thing on for a few minutes in the previous test runs, and thought that it was surely going to get worse. But it didn't, so I can keep the can.

It did suck in the top pretty good, the sides caved in slightly, and it did lift up off the floor a bit. But no good crush-the-can pic. Sorry to disappoint.

You can see the system in the pics below (minus the last few runs of flex hose). By the way, yes there's some electrical conduit used. That's because a friend of mine had some 6" and 4" conduit that I could have and the 90's are the long, slow bend that are good for this kind of thing. I had to mix in white fittings and ended up with what might be one of the only two-tone ducting systems in the area.

Looks like I'll need another post to finish the pics.

Rob
 

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#14 ·
What I did for my system is I built an airtight cavity with a door where the trash can sits, the flex line can be replaced with a hard line to the top of the cavity. so you just set the trash can inside the cavity beneath the hole. this way all the vacum acts on the walls and door in the cavity and the can only acts to catch the dust...
 
#16 ·
What I did for my system is I built an airtight cavity with a door where the trash can sits, the flex line can be replaced with a hard line to the top of the cavity. so you just set the trash can inside the cavity beneath the hole. this way all the vacum acts on the walls and door in the cavity and the can only acts to catch the dust...
That's an interesting approach. I like it. Now I want to build one with one of those "Star Trek" doors that make the cool noise when they open.:laughing:


If it were me, I would make a 3/4" plywood donut to fit almost the full inside the trash can lid. Run some screws through the lid to make the plywood part of the structure of the lid. (Pre drill the holes through the lid and just before attaching the plywood, put some caulking compound on each hole.) You may have to add some ribs to the plywood donut for additional stiffening but I doubt it. Try to add spacers between the donut and lid so that your stiffening doesn't distort the dome of the lid.
That sounds like a good idea. I may just have to do that. Thanks.

Rob
 
#15 ·
I'm astounded that you're collapsing the trash can. I have a 33 gallon (? typical) trash can and a separator. This is on my Jet 1100 (I think) CFM DC. I can tell that the can is air tight as the hoses shrink when the DC is running. While I can't lift the separator/lid off the can while the DC is running, the can doesn't cave in.

Another thought - - -
(No it didn't hurt. :no: )

What you are probably hearing is the lid caving in. If you think about it, if the DC just develops 1 PSI of negative pressure, with a 20" diameter can, the lid is supporting 314 pounds. The trash can lid is not intended to be a structural device. (There are no ridges like the sides of the can.)

If it were me, I would make a 3/4" plywood donut to fit almost the full inside the trash can lid. Run some screws through the lid to make the plywood part of the structure of the lid. (Pre drill the holes through the lid and just before attaching the plywood, put some caulking compound on each hole.) You may have to add some ribs to the plywood donut for additional stiffening but I doubt it. Try to add spacers between the donut and lid so that your stiffening doesn't distort the dome of the lid.
 
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