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Dual hoover dust extractor

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chris.gid

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Hi, was looking for some advice before i spend a weekend messing around with ducting.
I have a few spare hoovers lying around I've been using for dust extraction from jobsite table saw, track saw etc in my shed. Thinking of getting a cyclone to increase dust collection capacity (as bins on hoovers are small). Cyclones have 50mm dust ports, so was thinking i could connect 2 of the hoovers with 32mm hoses (2 a same model dysons) with a y joint for some extra CFM (as a 50mm hose has greater area than 2x 32mm hoses).

Has anyone ever tried or seen this before, cant see anything on youtube or forums, so dont know if that because no one has tried it or because it doesn't work (ie the 2 hoovers just fight each other rather than pulling double air volume).

I know a proper dust collection system would be preferable but for the bits weekend woodworking i do i'd rather spend the money on new tools rather dust collectors.

Thanks
 

Sheptonphil

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The reason you won’t find much on you tube is because it’s a bad idea, period. They will fight each other, not double the extraction as per your thinking. You won’t find a commercially made setup with two vacuums and a Y piece.
 

sunnybob

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The first five minutes can be skipped to get to the dual extractor bit.
Stumpy nubs has made a lot of videos on dust collection.
 

Inspector

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The impellers in Stumpy's video is in series, one after the other. Chris wants to mount them in parallel, side by side. They might fight for air but you guys have a number of dual motor vacuums in your market. In essence the same thing. If he/she wants to play with them he/she is free to try. Report back to let us know how you get on. One thing though use/make a long Y rather than a short abrupt one that creates more turbulence.

Pete
 

DBT85

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The impellers in Stumpy's video is in series, one after the other. Chris wants to mount them in parallel, side by side. They might fight for air but you guys have a number of dual motor vacuums in your market. In essence the same thing. If he/she wants to play with them he/she is free to try. Report back to let us know how you get on. One thing though use/make a long Y rather than a short abrupt one that creates more turbulence.

Pete
There are indeed plenty of dual motors vacs on the market, my dx4000 is one. I'm not sure how they would compare to two separate units. In mine both are within the same housing and then share the same 100mm inlet, rather than both being in separate units and connected via a Y to one 100mm inlet. I'm not sure it should make any difference.
 

chris.gid

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Thanks for the comments.
I'll go down to Screwfix over the weekend and get some 50mm pipe to play with.
Any ideas for comparing power? I can try sucking up a pile of sawdust and compare times. Also saw Peter Parfit do something with the dust collector sucking down another tube on a bungee cable, may give that a go if I have some time.
 

chris.gid

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There are indeed plenty of dual motors vacs on the market, my dx4000 is one. I'm not sure how they would compare to two separate units. In mine both are within the same housing and then share the same 100mm inlet, rather than both being in separate units and connected via a Y to one 100mm inlet. I'm not sure it should make any difference.
Have you looked how your vac works, is it just 2 impellers side by side or is there some sort of ducting going on?
 

DBT85

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Thanks for the comments.
I'll go down to Screwfix over the weekend and get some 50mm pipe to play with.
Any ideas for comparing power? I can try sucking up a pile of sawdust and compare times. Also saw Peter Parfit do something with the dust collector sucking down another tube on a bungee cable, may give that a go if I have some time.
How fast it sucks the dust would be difficult to judge I think. Assuming you can turn one on and then turn on the other, you should feel a difference.

Have you looked how your vac works, is it just 2 impellers side by side or is there some sort of ducting going on?
The DX4000 is literally 2 motors mounded to a bit of steel which is the lid. The motors are covered in a cylindrical filter and then a paper filter. Best seen below. Maybe this works differently to two seperate units becase they are both contained inside the same drum? They are both fighting for air though.

Mines identical, but old enough that it's blue so the design hasn't changed. It sucks and you absolutely notice the second motor turning on.
 

Inspector

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You can make a simple water manometer for suction power. U shaped tube of water with some food dye in it. With a help DC you have to account for 15" of water column difference or less. With a LVHP vacuum you need to account for 80 to 150 inches or more of water column. For flow you need to setup a test duct and either a hot wire or pitot static anemometer. Probably cost as much as one if not both your vacuum cleaners. A fan type anemometer is next to useless for dust collection measurements especially with small ducting.

Pete
 

bp122

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A while ago I came across this. This guy used two units and housed them in a box to reduce noise. He also made his HEPA grade.
Worth a look.

 

MikeJhn

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May be worth looking at HVLP spray units, they mostly use a single motor with multiple impellers called stages to blow air to the gun, my four stage Fuji unit is very efficient, I did look at making one, but gave up when one came on e-bay I could not refuse, lots of units on e-bay as replacement fans/vacuums, make sure you do look at the separate units, i.e. ones with the impellers in a separate housing mounted to the motor on the other side of the bearings, its just a thought?
 

chris.gid

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Thought I would share an update on how this went for future reference.
2 vacs in parallel works just fine and gives a noticeable increase in airflow.
At the moment I've only really tested it by sticking my hand over the end of the cyclone but you can feel the difference on airflow.
Waiting to go to Axminster tomorrow to get some 50mm flexible hose as I only have 32mm hose to hand.
IMG_20200927_113541.jpg
 

DBT85

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First person to use 9 cyclones in one workshop!

As I said, not sure why it would be any more an issue than them both being in the same can like mine are. Apart from possible overheating maybe?

Given the inlets on both though you might find a single £90 100mm shop vac might be itentical to those. Not sure Dyson list the airflow anywhere.
 

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Closest thing I could find was a chart of static pressure lift. Vacuum Chart The Dyson upright (45") isn't any better than any other and a pair of them at best wouldn't be double in this instance because of the hoses. Still a novel way to get more with watcha got. While a shop vac would likely be better used built in central vac would probably be the most powerful. The 110V ones mostly used here have 140" or so of lift with the one 220V version I can find having 210" of water column lift.

Pete
 

robgul

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Thought I would share an update on how this went for future reference.
2 vacs in parallel works just fine and gives a noticeable increase in airflow.
At the moment I've only really tested it by sticking my hand over the end of the cyclone but you can feel the difference on airflow.
Waiting to go to Axminster tomorrow to get some 50mm flexible hose as I only have 32mm hose to hand. View attachment 93076
You could send that picture to James Dyson - he could produce a product and charge a fortune for it (like all Dyson stuff) - nothing sucks like a Dyson
 

chris.gid

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Closest thing I could find was a chart of static pressure lift. Vacuum Chart The Dyson upright (45") isn't any better than any other and a pair of them at best wouldn't be double in this instance because of the hoses. Still a novel way to get more with watcha got. While a shop vac would likely be better used built in central vac would probably be the most powerful. The 110V ones mostly used here have 140" or so of lift with the one 220V version I can find having 210" of water column lift.

Pete
Has anyone on this forum actually compared a shop vac to a domestic hoover?
They all work on the same principle and I think there are a lot of people that swear by Henry's. The only comments I have seen is about filters clogging up and not being suitable for prolonged use (and cyclone pre filter addresses most of those issues).
Would be interested in knowing if anyone had actually compared a hoover to a festool side by side.

Btw I can't believe how well those Chinese cyclones on a bucket work. I sucked up a load of sawdust and used it on the circular saw cutting up old scraps for firewood and hardly anything ended up in the dysons. (Ignore the pic above, I sucked up a pile of sawdust without the cyclone to see of they were both sucking a similar amount).
 

DBT85

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For smaller tools a domestic vac or Henry should be fine within reason. There's limited airflow anyway as those tools might only have 30mm ports.

I just wish there were a few more of those cyclones with bigger ports. The tiny ones are dirt cheap but only 40 or 50mm inlets. Maybe I need to make a 2 or 3 cyclone bin using the smaller ones :ROFLMAO:

EDIT: the Axminter 100mm one isn't actually as expensive as I assumed it would be. They do say its unsuitable for HPLV though I can't fathom why.
 
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