Collapsed dust extraction container

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dsteve250174

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Marston Moretaine
Hi

I’m sure some of you must have had this issue before - I cobbled together my fairly limited dust extraction system a few months ago and it’s been working fine, but I was involved in a fairly lengthy sanding session getting my shed ready for repainting when the 30 litre container collapsed, see pic.

I have a shop vac and a cyclone (which had been attached to the now collapsed bucket.

So, can I ”re-inflate” the existing container or, just get a new one (bit concerned that it is now badly weakened) … more importantly, how can I prevent this happening again?

David S
 

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I don't have one but i have read that you need some sort of pressure release/equalizer gizmo fitted that prevents this from happening. Even metal ones can collapse.
 
A plywood ring inside the container about half way up would probably prevent future collapse - but I am not sure whether this just fixes the symptoms rather than the cause.
 
I don't have one but i have read that you need some sort of pressure release/equalizer gizmo fitted that prevents this from happening. Even metal ones can collapse.
Thanks - I had watched several videos before I got the cyclone but none of them mentioned a release valve - I’ll get one if I can unbuckle my existing drum.
 
This was the one that I bought - drum though the price has gone up a bit since i bought. :( I can highly recommend the company though, as they were very prompt to address a slightly faulty seal on the lid and were even ready to ship a replacement drum without even seeing a photo of the seal.

G.
 
A good demonstration of the capability of atmospheric pressure, would please many a physic's teacher.
This was a common problem on the old Mercedes W126 S Class. If the breather for the petrol tank got blocked it could collapse almost flat ! Amazing to see when you think how robust the steel 100 litre tank looks.
 
I made a square unit from MDF, all sealed at the edges and around the top rim. I even sealed the surfaces with a dilute PVA adhesive. I had the MDF kicking around and this, together with sealing tapes and clips cost me about £15.

I put a plastic bag inside to collect the dust and turned it on. The plastic refuse sack was instantly sucked up inside and a horrible noise emanated from the unit - a bit like the OP.

I took it all apart and put a weight in the bottom of the bag. It now works a treat and doesn't take up a lot of room.

The pressure release value will reduce the vacuum if the pressure becomes so great as to collapse the container. I don't have one on mine and I cant see any evidence of a collapse.
 
This was a common problem on the old Mercedes W126 S Class. If the breather for the petrol tank got blocked it could collapse almost flat ! Amazing to see when you think how robust the steel 100 litre tank looks.
That says a Lot about the fuel-pump, doesn't it ?
 
When I put mine together I added a 'pressure valve' (simple spring over cut out).
Darned if I can find the drawing, it may even have been on here?
Never had a collapse yet?

Anyone seen that idea to help out the OP?

This one I think.
 
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Barrel collapse is a common problem on cyclone extractors, sorted with a pressure release valve as many U-Tube vides show, Peter Parfit explains it perfectly.

 
Based on my experience, the dust bin or bin top is the worst place to put a Pressure Relief Valve (PRV). Any break in the dust bin seal will cause the contents of the bin to be sucked up through the cyclone, through the impeller, and into the filter. The best location for any PRV is in the ducting before the cyclone.

I use a 35-gallon plastic trash bin for my dust collection system and it collapsed once when I closed the only open blast gate while changing from the P/T to the table saw. I didn't notice the collapse because my DC system is in a closet. By the time I noticed the substantial degradation in the DC performance, about five minutes later, the contents of the previously half-full dust bin were now in my filters and the dust bin was empty. It took me over two hours to empty and clean the filters, plenum, and impeller.

I fixed the collapsing problem with a simple insert made from plwood offcuts and ensuring at least one blast gate is open at all times. Since fitting the insert over two years ago, the bin has not collapsed and my filters are still clean.
 
Based on my experience, the dust bin or bin top is the worst place to put a Pressure Relief Valve (PRV). Any break in the dust bin seal will cause the contents of the bin to be sucked up through the cyclone, through the impeller, and into the filter. The best location for any PRV is in the ducting before the cyclone.

I use a 35-gallon plastic trash bin for my dust collection system and it collapsed once when I closed the only open blast gate while changing from the P/T to the table saw. I didn't notice the collapse because my DC system is in a closet. By the time I noticed the substantial degradation in the DC performance, about five minutes later, the contents of the previously half-full dust bin were now in my filters and the dust bin was empty. It took me over two hours to empty and clean the filters, plenum, and impeller.

I fixed the collapsing problem with a simple insert made from plwood offcuts and ensuring at least one blast gate is open at all times. Since fitting the insert over two years ago, the bin has not collapsed and my filters are still clean.
Mine is in the lid of my bin and I frequently 'activate' it when I accidentally occlude the hose, and it has never caused anything to be sucked up into the extractor. I wonder why yours does that and mine doesn't? I'll put some photos up later on.
 
Mine is in the lid of my bin and I frequently 'activate' it when I accidentally occlude the hose, and it has never caused anything to be sucked up into the extractor. I wonder why yours does that and mine doesn't? I'll put some photos up later on.

It's not just mine that does this. Everyone I know with large extraction systems like mine (3HP) that had leaks in the bin have experienced the same nasty results. It only takes one time to learn the valuable lesson of preventing leaks in the system. It's possible that intermittent leaks won't have the same effects, but could over time.

The other filter-clogging event occurs when the bin is full and the end of the cyclone is blocked. At that point, chips and dust start going to the filters as the cyclone fills. Unless the bin is emptied, eventually the cyclone will fill and everything will go to the filters.
 
I wonder if your leak allowed air around the other side of the bag (between the bag and the barrel? I dont know how I get away with it then because I dont have that issue, and the release valve goes off all the time on mine so it isn't a rare occurance.
 
I wonder if your leak allowed air around the other side of the bag (between the bag and the barrel? I dont know how I get away with it then because I dont have that issue, and the release valve goes off all the time on mine so it isn't a rare occurance.
No bag in my DC. Here's my system.

23608697328_f262e5ac97_c.jpg
 
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