Homemade cyclone dust collector collapsing

[Moller89]

Hello,
I have a 1.5hp Charnwood w680 dust collector which is then connected to my cyclone seperator. This is via a 2.5m flexible hose from extract to cyclone it is 50mm diameter. The cyclone is connected to a 220litre plastic barrel with screw on airtight lid. The cyclone then feeds out to a 50mm 2.5m flexible hose which is then positioned near my lathe. Everytime I turn on the extractor the barrel starts to collapse under the pressure/ suction?? Any help? Is the cyclone too small or flexible hose to narrow?

 

[Inspector]

Deleted. Too wordy.

Pete

 

[Roland]

Make an internal rib, and make sure the top is strong enough too:

 

[Spectric]

The barrel tries to implode because the air is being extracted faster than the air can enter which would then suggest a lower airflow and airflow is what you need not large pressure drops.

 

[robgul]

I had the same problem - I just made a box about 40cm cube from OSB with a cased lid that had the cyclone mounted on it - all the joints sealed with caulk, draught excluder on the lid and over-centre clamps. Works a treat.

 

[TheTiddles]

There seems to be a competition going as to who can make the most wordy explanation for something very simple... your barrel isn’t strong enough (at least Roland managed it).

Using hose that’s about 25% the area that the extractor is designed for will make your problems worse (less flow, higher pressure differential)

Aidan

 

[Sachakins]

You could add a vacuum/pressure relief valve to the barrel.
https://www.festoolownersgroup.com/...esetting'-pressure-relief-valve-for-cyclones/

 

[gog64]

There seems to be a competition going as to who can make the most wordy explanation for something very simple... your barrel isn’t strong enough (at least Roland managed it).

Using hose that’s about 25% the area that the extractor is designed for will make your problems worse (less flow, higher pressure differential)

Aidan

You are probably right, but I’m not sure it’s quite that simple. I have a very similar barrel and it works perfectly. The difference is a much bigger cyclone and 100mm pipes. You could beef up the barrel but I would be concerned that by restricting the airflow so much, you might strain the motor in the extractor?

 

[shed9]

Just use a metal barrel, stronger and have better seals on the lid. Dirt cheap and plenty come up on local Facebook market place.

Oh and yes, as pointed out, wrong sized cyclone relevant to the extractor. Repurpose the current bucket / cyclone to a smaller vac for power tool use and use a metal barrel / larger cyclone with the Charnwood 1.5HP unit.

Alternatively look at building a thien baffle design.

 

[Inspector]

There seems to be a competition going as to who can make the most wordy explanation for something very simple... your barrel isn’t strong enough (at least Roland managed it).

Using hose that’s about 25% the area that the extractor is designed for will make your problems worse (less flow, higher pressure differential)

Aidan

You'll be happy to know I have fixed my post.
Also note I will not participate in anymore dust threads to prevent future occurrences.

Pete

 

[Sideways]

That's quite a large barrel.
I find that a smaller sized standard blue plastic barrel is stiff enough not to collapse regardless of choice of hoses.
It needs to be emptied a little more often but is smaller and lighter to manhandle when full.
Beware of warming plastic barrels up - one one occasion with the cyclone barrel standing in the warm exhaust airflow from my vacuum, the plastic softened and did begin to deflect.
One advantage of a plastic barrel is that it's unaffected by a little oil or damp. That makes it handy for hoovering metal swarf off the lathe even if sticky with cutting oil or coolant. For infrequent use, nothing makes it past the cyclone to trouble the vacuum.

 

[sometimewoodworker]

Any help? Is the cyclone too small or flexible hose to narrow?

Yes, yes, and collection barrel is not strong enough.
For a lathe you need maximum airflow and you have reduced the flow in (1,963.5)to ¼ of the suck out (490.9) and that doesn’t allow for the reduction in suck (mass of air moved) of the cyclone.

as mentioned above;
use a 50 mm hose to the lathe
use the shortest hoses possible
if that isn’t enough, strengthen the barrel

Note a pressure relief valve in the barrel will reduce the cyclone efficiency.

Also almost all flexible hose has a bad effect on suck (reduction in mass of air moved due to turbulence created by concertina pipe wall) so use the shortest length possible. There are semi flexible hoses with a smooth interior that are far better, but much more expensive, than the hoses you are using

 

[harryc]

Pressure release valve.

 

[sometimewoodworker]

Pressure release valve.

Your point is?

 

[harryc]

Your point is?

https://www.dust-commander.com/gb/p/19-dust-commander-dust-sp-anti-crush-valve-3760013430467.html

 

[matkinitice]

https://www.ukworkshop.co.uk/thread...apse-with-a-relief-valve.129595/#post-1455498

 

[MARK.B.]

You'll be happy to know I have fixed my post.
Also note I will not participate in anymore dust threads to prevent future occurrences.

Pete

Post away in any and all subjects Pete , some people may not like your style and thats up to them, i for one like your answers to most queastions and enjoy seeing you're posts

 

[Chris_Pallet]

I have small blue barrel cyclone set up attached to an old dyson.
Hose kit £15 amazon.
No issues so far.

Nice to see the wooden box job working

 

[Lakeburch]

I've only just set mine up and decided to go for three buckets after reading too many accounts of the blue barrels collapsing.
No problems so far but still early days.

 

[sometimewoodworker]

https://www.dust-commander.com/gb/p/19-dust-commander-dust-sp-anti-crush-valve-3760013430467.html

Just because someone is selling a product doesn’t make it good or sensible to use it, nor does it change the fact that a correctly built and or resourced bin will function without one and adding one reduces the efficiency of the cyclone allowing dust to bypass it

There are a lot of products that are solving problems in the wrong way