A Dyson Dual Cyclone Dust Extractor

[Turbulance]

Hi Forum Members

I am new Perth member, and would like to share some discoveries in the world of Dust Extraction.

Has anyone experimented with a Dynson style dual cyclone dust extractor - this is based on a two stage process where the first cyclone removes to bulk dust and chips etc. and then a second smaller cyclone that removes the fine dust?

I ask this question because, when I started a couple of month ago, to get really serious about woodworking all I had to get rid of dust was an old 1200 Watt VAX. This had a disposable paper bag, and was connected to my mitre saw, belt sander and electric planer, using 30mm pool cleaner hose from Bunnings. It worked, and did seam to keep some of the bulk dust out of the shed.

At the time I had no thought of getting fine dust, and no intentions of trying to use such a system on a Bandsaw, Jointer, Table Saw, Router Table etc.

Anyway the reason I had the VAX in the Workshop was because we had bought a Dyson vacuum cleaner for the house, and I was very impressed with the way it worked, no bag, and it could extract very fine dust with no problems. (We got the Dyson because I used to be a workshop cleaner and I hated dust bags!)

It got me thinking that I could make such a system - a bit larger - for my home bred dust extraction in the workshop. So I did - and to my horror it works very well. (No one told me that it wouldn't work, or that it as too small - too much knowledge is a problem sometimes.)

Running until the collector is full - which is not much at the moment, about two buckets of saw dust - I have very little dust in the base of the VAX, just a coating on the paper filter which can be vacuumed off with my smaller cleaner. Using this cyclone I can pull dust over 10 meters for all over the shed. It can handle all the chips from my 80mm electric planner, and seams to get most of the dust from my router table, but is not much use on the bandsaw.

The down side is that it currently only working using 30mm piping - but I was hoping it would not be too hard to scale it up to work for large duct sizes, (in fact I have already built the second prototype, with seven small cyclones, for use with 100mm ducting, but I don't think the VAX has the pull to make it work properly as I get too much dust in the VAX, and I am now working on making an new impeller style blower to replace the VAX but I am starting to get some doubts as I started to learn too much about the issues of dust extraction.)

My expectations took a bit of a dive once I found all the information on Bill P's Cyclone site, and started to understand some of the issues involved in getting fine dust, and the amount of air that has to be moved, but I am not willing to give up on the design just yet.

Another fly in the ointment would appear to be that Dyson hold a patent on their Cyclone designs. Still if I am only making one for home use I am sure that I am not breaking any laws and it is my own design anyway.

The interesting thing about the Dyson design is that it is compact, and appears to work on a different principle to the standard Cyclone, by creating very high rotational velocities to throw out even the finest dust. Dyson claims that his dual cyclone system can even remove tobacco smoke!

I have attached some pictures of the first prototype – which has been working now for about two months, and was made for various lengths of PVC piping and an old detergent bottle. The second prototype removes the second cyclone and replaces it with seven mini cyclones in a separate extractor, but as stated above this design is not working as well as I hoped, after the success of the first it was a bit of a let down, but as I have said above I haven't given up on it yet.

Any thought would be welcome.

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Pictures show:

1) The Dual Cyclone altogether ready for use with the VAX connected
2) The inside of the first Cyclone - you can see why it fills quick needs to be put on a bin, but that will come later.
3) The second cyclone which fit inside the first
4) The Fine dust that is collected in the inside bottle which is attached to the bottom of the second cyclone


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Regards all

Paul

[BrianR]

You have some good ideas in this device. Each stage will extract more dust but in the end the extraction is based on the dust particles weighing something so they get thrown to the outside of the cyclone and ultimately drop to the bottom. The fine dust will require very high velocities to achieve this causing significant back pressure losses in the system. The dangerous dust is that stuff only a few microns in diameter and I do not think you will get any satisfactory removal with a cyclone system. In the end I think you'll find it more practical to use 1 or 2 stages followed by a filter.

In fact a filter made from needle felt (and you can buy quite a large unit for under $50) will filter down to 1 or 2 microns and is washable.

I also started with a Vax similar to yours but found it could not move enough air to be really useful. It was finally relegated to my compound saw and a 2hp el cheapo dust extractor modified by the addition of a 1500x500mm needle felt bag replaced it. Large diameter lines are needed to distribute the vacuum and I used 100mm but now find them too small as there is a lot of back pressure loss over 10m of line. In time I will replace the 100mm line with something larger.

[bongodrummer]

Hay Turbulance, interesting stuff. I have made a similar arrangement, but using clear polycarbonate so that I can see it working. It works exceptionally well, but to use it on things like a bandsaw, I have had to do a lot of modification to the design and location of the dust ports. Making them collect the dust right at source, really utilises the speed at which little vacuums can suck up.

Anyway, I did a big write up about making the cyclone here (http://www.floweringelbow.co.uk/projects/the-cyclone-dust-separator/) if interested. Cheers.

[Master Splinter]

As Turbulance hasn't been active since 2004, there's probably slim chance of him seeing your post. Just sayin'.

[TP1]

I have been using the Oneida Dust Deputy for a while now ( as have other forum members) and it already captures most of the fine dust that is vacuumed. In fact I had almost filled it while it was attached to a wide drum sander with very little getting through to the Festool Dust extractor.

I actually have 2 of these for different applications and I may experiment with them in tandem. But given the tiny amount that gets through now ( less than 1%) it may be overkill in my setup.

[Morbius]

I think the Dust Deputy might be my next purchase as well as a Haefco. DC1.

https://www.machineryhouse.com.au/images/20422.jpeg

Craig