Homemade cyclone extractor.

[sometimewoodworker]

I disagree.
The catchment container can be flimsy plastic & should not collapse as the air flows freely through the system. If it starts to collapse then the air is being restricted somewhere within the system & causing a vacuum. Strengthening the dust container is not the right answer.
Much better to sort out the restriction & add a PRV as a precaution against whatever is being sucked up causing a blockage.

Not correct if using a HPLV vacuum, it’s probably correct using a HVLP chip extractor.

with HPLV sucking from most tools you want maximum suck availability at the tool, this requires a small hose from the cyclone or adapter to a small fitting at the tool either will collapse your flimsy plastic catch bin.

With HVLP (almost always 4” to 8” pipe) you get very inefficient collection from tools designed to be used on HPLV dust extractors, while you have to restrict the catchment down to 27mm you reduce the flow needed in the system to transport the chips/dust.

so in short HPLV needs a strong container to function.
NOTE it is high pressure low volume. No a pressure release valve or somehow converting it to 4” hoses is absolutely the wrong answer and would get you a LPLV system that is bad at doing collection.

A PLV is a bodge addition by people trying to solve a problem in the wrong way.

 

[Robbo3]

I stand by my previous post.
To clarify for future readers, I am referring to domestic workshops using a cyclone or Thien baffle with 32-50mm ports & either a domestic vacuum cleaner or a shop vac.

 

[sometimewoodworker]

I stand by my previous post.
To clarify for future readers, I am referring to domestic workshops using a cyclone or Thien baffle with 32-50mm ports & either a domestic vacuum cleaner or a shop vac.

Then as I said you are using HPLV systems and the catchment bin needs to be strong enough to resist the lower pressure that is inherent in their design.

Your introduction of a light weight plastic bin doesn’t work well in that system. The system is designed to create low pressures that will collapse an insufficiently robust collection bin under the cyclone.

you are trying to graft features of a HVLP system onto a HPLV one when strengthening the collection bin is the correct answer.

For proof look at the strength of the collection bins designed into the shop vac, you can be absolutely sure that if a light weight bin would do the job that is exactly what would be used, they don’t use them because they don’t work.

you have already reduced the pressure by adding in a cyclone or Thien baffle reducing it more by adding in a flimsy barrel needing a further reduction by a PRV means you are dropping effectiveness even more.

can it collect dust? Of course it can. Can it collect dust as well as a system that has correct strength items? Of course not.

 

[Roland]

Whatever the arguments, this is what happens in practice. The cheap Chinese cyclone is attached to a Numatic HPLV extractor. The bin is a brewing bucket, and the lid is held tight by air pressure alone.

The bin is only in danger of collapsing if the inlet is blocked. This plywood frame prevents that.

 

[TominDales]

It really is great. I use it for cleaning up after lime work and evreything - ie sucking up wet mortar.

I reckon you could suck up water with it happily, but I've not tried more than small puddles when hoovering other stuff.

Its NOT recommended to use water. A well designed cyclone - like the Chinese copies of the original US design will separate and catch particles really well. And very fine ones as Julian says. But water can vaporise under a partial vacuum and condense in the motor and write off your Henry/Tesco.

 

[sometimewoodworker]

Whatever the arguments, this is what happens in practice. The cheap Chinese cyclone is attached to a Numatic HPLV extractor. The bin is a brewing bucket, and the lid is held tight by air pressure alone.
View attachment 106248
The bin is only in danger of collapsing if the inlet is blocked. This plywood frame prevents that.
View attachment 106249

That was what I did until I needed more collection volume and built the container in post #38, though it isn’t completely airtight and so let’s through about 5%

I haven’t bothered to check yet to find out where the bypass air is entering the box

 

[skeetstar]

Just an update, and thanks to those who responded to my questions of earlier in this thread.

I've got my self another Henry hose to replace the thinner dia one that was attached to the saw. Now my primary and secondary hoses are the same internal Diameter.

I got a chap called Dan Goodier to make me some adapters, so now I have custom made adapters connecting the hoses to the cyclone. The adapter dimensions are such that they fit over cyclone spigot and the hose end, so the joints wont restrict airflow.

Dan will make any size adapter you want for about £8.00 delivered, the pic is an example of one he has on his own cyclone... If you fancy one just put Dan Goodier Adapters into google and you will find him. (or PM me and I'll send you his details).

Next I need him to make me an a proper adapter to fit the Henry hose to my cross cut saw and we are up and running, but a test with what I have ATM shows a marked improvement.