Ultimate DIY Separator / Extractor

**HeadScratcher** · 11th July 2012, 08:17 PM

Ok having built a separator based on the Thein baffle design, I now think it is time to step it up another notch to see if the collective intelligence of the forum can come up with something better than the commercially available units. Big ask I know but let’s put our thinking caps on and give it a go…

So kicking off let’s take a look at some of the perceived short coming of the Thein baffle design I just completed. Again this is only my perception, not gospel and you are welcome to argue the point, and add other suggestions as you see fit.

Firstly thing that stops the one I just built being the “Ultimate” design is that it isn’t see through… why is that important in the grand scheme of thing? Well it is only a very minor point, but being able to see the dust swirl around the separator and through the slot around the outside circumference is a very useful for analysis, it could be made longer or wider if it was visibly obvious that a lot of the dirt wasn’t being allowed to pass to the bottom of the catchment container, without the risk of making it too large and losing efficiency. Also being able to see into it would give better insight as to how well the dust is being held against the wall of the container, highlighting if more flow or pressure was required.

Second thing is the entry from the top… it has to go through several bends before even getting a shot at entering the top section. Based on the flow restriction figures provided by Bob on 4” pipe the 90mm (3.54”) pipe I used is well short of the “Ultimate” flow. So I would propose that in the ultimate separator that the entry would be from the side.

Third thing is the location of the entry, in my version I used a round pipe pointed towards the wall, some of the sawdust might glance off the wall as a result of the angle it hits it. From what I have read the most efficient design is one that allows the most seamless and unhindered flow inside the chamber. For this reason I would propose that the entry be shaped something like the letter “b” (when viewed from the top) where the inlet is part of the outside wall. Imagine for a moment you got a piece of thin clear Perspex and bent it in a circle but instead of butting the two ends together you pull the bent end in towards the centre creating a spiral effect and forming the outside edge of the inlet.

Now you might ask how are you ever going to hold that in place so it doesn’t try to spring out? I was thinking of two octagonal pieces of MDF with a roundish shape matching the Perspex grooved into the top and bottom plates. With an additional groove cut top and bottom to form the second side of the entrance. Using four or six pieces of threaded rod and some nuts, the top and bottom pieces of MDF could be bolted down trapping the Perspex in the grooves like a sandwich traps filling.

This would now give us an entrance that was square or rectangle. We could also optimise the shape of the entrance to be of the greatest effect by making it tall and thin. The dust needs to be flung against the wall upon entry and kept there, and the best way to do that would be to make use of the full height of the clear Perspex wall we have just built. By making it more rectangle than square it places the dust closer to the slot and keeps it further away from the outlet. The area of the inlet could be made to match the size of the pipe that would be feeding it so no low pressure point were created when transitioning from the pipe to the inlet. Granted may need to get creative on the adaptor from round to rectangle or could possibly use some off the shelf adaptors.

We could also extend the other side of the inlet so that it run parrallel to the outside wall, to give the dust a better oportunity to escape down the slot while keeping the dust away from the outlet, hopefully by the time the inside wall finished all of the dust would have fallen through and only air would come out the end of the inlet tunnel.

Ok so that pretty much completes the top section (other than the outlet) below the baffle I would look to use some clear Perspex again to view the flow of dust into the catchment container. Creating a cone and tapering it just like all of the other cyclones on the market to reduce the volume below the baffle, and to aid the dust clearing the baffle, and to also help place the dust in the centre of the catchment bin giving a more even fill pattern.

The cone section could be attached to an MDF lid of the catchment bin in the same way as the top section is held together, so you would wind up with something like a triple bread sandwich with two fillings, the top section and the cone below.

Ok so there is the basic idea I have in mind pull it apart, examine it, and suggest improvements for the ultimate DIY separator.

**Chris Parks** · 11th July 2012, 08:48 PM

Perspex top and meets most of the above criteria
Mini CV06 Home - Mini CV06

**HeadScratcher** · 11th July 2012, 10:12 PM

lol how funny is that I nearly described it to a T

This is more what I had in mind CV1800 LH - Cyclone Body Only - Clear Vue Cyclones

Pity there are shipped out of the U.S.

**Chris Parks** · 11th July 2012, 11:02 PM

Originally Posted by HeadScratcher

lol how funny is that I nearly described it to a T

This is more what I had in mind CV1800 LH - Cyclone Body Only - Clear Vue Cyclones

Pity there are shipped out of the U.S.

We stock them in Australia, yes they are sourced form the US.

**HeadScratcher** · 12th July 2012, 12:12 AM

Hey Chris, sorry my fault I wasn't overly clear by my last comment... If you read between the lines what I meant was they are like to be too expensive by the time they are imported. Not that I actually care that they come from the U.S.

Often things can look reasonably priced overseas but then you price them locally and they are no longer viable. Occasionally you can be pleasantly surprised but it doesn't happen very often. One such case was my tweeters for my new speakers I actually bought them cheaper them I could overseas.

If those cyclone bodies were $450 in my hand in Australia then it would be worth buying something pre made, but add typical Australian mark-up and all of a sudden they are no longer viable and your back to DIY.

Been playing with SketchUp and this was what I had in mind… It is somewhat similar to the photo Chris posted. The one in the picture is narrower so it uses the outlet tube as a wall, but it doesn’t have the baffle on the bottom.

**Chris Parks** · 12th July 2012, 12:38 AM

So, what you are saying is that the retail price in the US should apply here? So if that price was $800 you would be happy to pay that? I don't mean to sound argumentative but that is the way it comes across.

**HeadScratcher** · 12th July 2012, 12:56 AM

No more along the lines of... $450 you could almost justify not bothering with going DIY and just buy it ($450 would be a high upper limit for me to justify for some shaped Perspex) , but at $800 you have to say to yourself that's too expensive, and with a bit of effort I could probably make it myself for sub $150 (Hence a thread for an ultimate "DIY" separator)

What I am saying is what is just affordable in the U.S generally wont be affordable in Oz and consequently why we are a nation of DIYers.

If I was a commercial business I might be able to justify $800, getting some back on tax, but as a weekend dust warrior, it is hard to justify when I'm already over budget on tools.

**Breezy** · 12th July 2012, 03:10 AM

Originally Posted by HeadScratcher

Been playing with SketchUp and this was what I had in mind…

It is somewhat similar to the photo Chris posted. The one in the picture is narrower so it uses the outlet tube as a wall, but it doesn’t have the baffle on the bottom.

HS This wont work, the dust/air needs to circulate several times to drop into the baffle slot. Phil Thein's baffle was designed to be used with trash can separators.

Watch these Youtube videos.

[ame=http://www.youtube.com/watch?v=dhnBvdeaWS8&feature=related]Dust Separator - Thien Concept 5 Final Test - YouTube[/ame]

[ame=http://www.youtube.com/watch?v=3QCAOwSqrko&feature=related]Thien Dust Separator - tablesaw test - YouTube[/ame]

The Clear Vue cyclones are based on BP's design which directs the dust into the cone which is a functional part of the dust separation process.

As per this video.

[ame=http://www.youtube.com/watch?v=nQQZkGFKTtU&feature=related]Homemade mini cyclone dust separator for shop vac. - YouTube[/ame]

**HeadScratcher** · 12th July 2012, 05:48 AM

Thanks Breezy that changes everything... I figured the other type spiralled in and down, but I didn't realise the Thein baffle may do several laps before dropping in. Seeing it flying around like that gave me a few ideas.

In the first video I see he used a square edge to get the long straight entry like I was aiming for. He should have put a small ramp on the right side near the entrance to lessen the impact on the incoming debris and dust (slight turn on the existing dust to face the same direction as the incoming dust), the right angle wasn't helping his cause.

Keen to know what he used on the sides of his extractor to give it the curved side. Wonder if it is that flexible MDF... don’t know what they call it.

Did you notice in the second video of the Thein baffle that he had a dead spot where dust gathered... Probably due to the unnecessary extra volume / height in the cavity section. The clear plastic made it easy to spot.

In the last video that was homemade... he did a very good job on that, I notice the ones that don't have the baffle have a much smaller diameter to keep the air speed up and help force the dust down. Also notice they angle the input down to speed up the process.

Is one type more efficient than the other? or does one type favour a bigger inlet / outlet?

**HeadScratcher** · 12th July 2012, 07:29 AM

Had another quick redesign... Reduced the fence quite considerably and tilted the inlet down since we are trying to get the dust to the bottom section. Opened up the side to let it recirculate.

Still just playing with ideas nothing concrete just yet.

**Chris Parks** · 12th July 2012, 11:25 AM

clearvue cv06 - YouTube
[ame=http://www.youtube.com/watch?v=8rU9iBlM2o0]Clearvue CV06 with clear dust barrel - YouTube[/ame]
[ame="http://www.youtube.com/watch?v=bxRSyte0pt0"]Clear Vue Cyclones Mini CV06 - YouTube[/ame]

The small clear home made in the post above looks like an original CV06. The story to that is Oneida threatened legal action if it was not removed from the market hence we have arrived at the present model. Two of the links above show it working and the person doing the demo with the vacuum cleaner is the original owner of CV and the person that Oneida threatened. I sold the last one in captivity to the CSIRO who wanted it for research purposes in a lab.

**Breezy** · 12th July 2012, 03:52 PM

Originally Posted by HeadScratcher

In the first video I see he used a square edge to get the long straight entry like I was aiming for. He should have put a small ramp on the right side near the entrance to lessen the impact on the incoming debris and dust (slight turn on the existing dust to face the same direction as the incoming dust), the right angle wasn't helping his cause.

Keen to know what he used on the sides of his extractor to give it the curved side. Wonder if it is that flexible MDF... don’t know what they call it.

The inlet should be a smooth transition into the side of the cylinder, both sides of the inlet, to simplify the construction he made the right hand side square which didn't help the performance. Go to YouTube and search for rawdawgs50 he has five videos on the dust extractor construction also look at ghostses videos again 5 of them. There are lots of other videos on dust extraction some good, some bad.

Originally Posted by HeadScratcher

In the last video that was homemade... he did a very good job on that, I notice the ones that don't have the baffle have a much smaller diameter to keep the air speed up and help force the dust down. Also notice they angle the input down to speed up the process.

This is a cyclone, a different beast altogether. You can't mix the two together. Phil Thein based his baffle on the cyclonic principle to improve the performance of commercial trash can separators which just circulated the air around a trash can to drop out the large debris, with the fine dust going to the DC. The problem with the basic separator, that when it was about quarter full the debris carried over to the outlet without dropping out. This video was included to show the principle of cyclonic separation. As pointed out by Chris Parks - The small clear home made in the post above looks like an original CV06.

Originally Posted by HeadScratcher

Is one type more efficient than the other? or does one type favour a bigger inlet / outlet?

The cyclone has been around for a long time. Bill Pentz improved upon it. Bill's Cyclone Dust Collection Research - Dust Collection Basics There is a lot to read on this site but all good info.
Cyclones are more efficient than the baffle, both consume power as BobL has pointed out. But with careful design power loss can be reduced.

Originally Posted by HeadScratcher

Had another quick redesign... Reduced the fence quite considerably and tilted the inlet down since we are trying to get the dust to the bottom section. Opened up the side to let it recirculate.

You don't want any obstructions between the inlet and outlet, the air needs to flow smoothly between the two. You are relying on the centrifugal force applied to the dust by the circular air flow to separate the two, with gravity pulling the dust down. The depth of the outlet pipe controls how the air flows within the chamber.

**HeadScratcher** · 12th July 2012, 05:41 PM

Sometimes I am prone to reinventing the wheel when the current wheel works perfectly fine.

I had a 2 second read of Bill's page and he suggests that cyclone is a more efficient design (when done properly). Based on the volume of air and the lack of obstructions, I can see how that would be the case.

The drum in the first video Chris posted is what I had in mind using threaded rod to hold it all together.

I really should use YouTube to research more often, I am re-inventing what people have already come up with...

All said and done provided the math is right, the whole concept behind these things is incredibly simple, but then again just like the wheel, sometimes the simple answer is the right answer.

**Chris Parks** · 12th July 2012, 06:01 PM

YouTube is the greatest asset on the net slightly ahead of Google images which is another priceless source of info, have a look at what I mean..

https://www.google.com/search?num=10...BuewiQfs6MTvBg

**HeadScratcher** · 12th July 2012, 06:16 PM

Thanks Chris... have to laugh I was kicking around the idea of a screw like slide to help guide the dust into the bottom (like a kids slippery slide that spirals). Someone has already beaten me to it. Building a Bill Pentz's Designed Cyclone

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