Thien Baffle for Camvac?

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Has anyone had any luck making a Thien Baffle type system for a Cam Vac (Twin Motor)?

I've been experimenting with something like this :

1630245880227.png


With only one motor enabled, it kind of works, but I want the extra power of two motors as I want to use it with my thicknesser. With two motors enabled, I get two issues :

1) The barrel collapses. Note, this isn't due to a blockage! it collapses with no blockage. So I am guessing here that the inlets are just too small? and it's an air flow issue? air is being sucked out of the barrel quicker than it can enter? ... both inlet and outlet are the same size pipe (50mm), so not sure about that theory.
2) Strengthening the barrel for the above issue (not a solution I know, but I wanted to experiment), and trying again. The Camvac is so strong, it sucks up anything collected at the bottom of the barrel.

Am I going to be able to get this working with 50mm pipework? I don't really want something that has 100mm pipes. I know that 100mm cyclones like the Axmintser craft ones exist, but I wanted this to be somewhat portable.
 

Rorschach

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What is the size of the pipe on the camvac? If it is 50mm, the same as your thien then you just need a stronger barrel I think.
 

Sideways

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Your Camvac is twin motor vacuum cleaner. They make high suction and move a modest but very useful amount of air at high speed. You have to expect a high suction inside the barrel if you want the same sort of air speeds through the inlet hose, it comes with the territory. I wouldn't expect a plastic barrel to be up to it. In my experience of the blue plastic variety they are on the limit with a decent single motor vac and if the plastic is softened by warm air from a heater or a hot day, they will start to collapse..
Also, A metal drum will be heavier and less likely to topple over when you pull on the hoses ....
 

johnnyb

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my thien baffle works great on my three motor vac. it's got a cheap galv bin as a collector the pipework not brilliantly sealed and neither the baffle to the bin!. it works really well on my table saw. I built it 5 years ago I think and it's in daily abuse! it will collapse the bin with a blockage or if the free end attaches to something..
 

Sachakins

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Sounds like 100mm pipework needed or put a deliberate leak/adjustable vent in to reduce the pressure/vacuum.
 

Fitzroy

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The barrel collapse is just because you’re using 50mm hoses. It’s the pressure drop from the collection point ( far end of hose) to the barrel. Only solution is a shorter hose or larger diameter hose. But it seems you’re solved it by reinforcing the barrel.

Second problem is more of a conundrum. The idea of the Thein baffle is that it directs the incoming air and sawdust round the side of the barrel, the sawdust separates through centrifugal action and/or momentum when the air has to change direction to get back to the outlet. The air in the barrel below the baffle should be at a low superficial velocity (large cross section of the barrel) such that it can’t pick the sawdust back up.

What could be happening is that with two motors on you are seeing a double impact on velocity. Firstly air rate has increased, and additionally as the pressure is lower you are getting even higher velocities are the density is also lower. I still struggle slightly as my expectation is that higher inlet velocities would improve performance as the dust has even greater momentum. I’d test if it is picking up dust from the barrel (ie put dust in the barrel first and turn it on, does it empty this dust) or just failing to separate the dust.

Fitz.
 
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The barrel collapse is just because you’re using 50mm hoses. It’s the pressure drop from the collection point ( far end of hose) to the barrel. Only solution is a shorter hose or larger diameter hose. But it seems you’re solved it by reinforcing the barrel.

Second problem is more of a conundrum. The idea of the Thein baffle is that it directs the incoming air and sawdust round the side of the barrel, the sawdust separates through centrifugal action and/or momentum when the air has to change direction to get back to the outlet. The air in the barrel below the baffle should be at a low superficial velocity (large cross section of the barrel) such that it can’t pick the sawdust back up.

What could be happening is that with two motors on you are seeing a double impact on velocity. Firstly air rate has increased, and additionally as the pressure is lower you are getting even higher velocities are the density is also lower. I still struggle slightly as my expectation is that higher inlet velocities would improve performance as the dust has even greater momentum. I’d test if it is picking up dust from the barrel (ie put dust in the barrel first and turn it on, does it empty this dust) or just failing to separate the dust.

Fitz.

If I fill the barrel with debris, and then turn on the extractor, after a few seconds all the debris gets sucked up into the extractor.

One thing to note though, is that I am using a rather small barrel. I think it's 25 litres.

I suppose a larger barrel would suffer the same issue when it's fuller though?
 

Sachakins

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Thein baffles become far less efficient as the barrel fills, so either a far deeper barrel or empty it at 25% full. A cyclone cone is more efficient, but far larger in size to house, especially if you go for 100mm inlet size.
 

Fitzroy

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If I fill the barrel with debris, and then turn on the extractor, after a few seconds all the debris gets sucked up into the extractor.

One thing to note though, is that I am using a rather small barrel. I think it's 25 litres.

I suppose a larger barrel would suffer the same issue when it's fuller though?

I think you need a larger barrel, 25l feels pretty small. You could also try rotating the lower baffle plate +\- 90degrees, may or may not work. The separation will improve with increasing velocity to a point then it’ll start to reentrain (assuming it works like a cyclone). Thinking about it ideally you’ll want a larger diameter barrel, not just a deeper one. The larger barrel will reduce superficial velocity, a deeper one will not.
 

Jake

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Camvac explain in their manuals that having fewer than all the motors on will reduce suction disproportionately because air will find an easier path through the off motors rather than the filter. So with a twin it is not a case of having 50% on single motor and then doubling it. Mine's a three motor and entirely subjectively I'd put it at something around 20%/50%/100%.
 

keithy1959

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Another vote for a bigger barrel. Also, its difficult to tell from the picture, but is the wider part of the bafflle ( that touches the barrel ) in the right place in relation to the inlet ? I found with mine that things worked much better with an inlet on the side through the barrel so I could rotate the baffle to get optimal performance.
I understand the sawdust drops as its weight makes it fall out of the airstream, so with the combination of the narrow barrel and two pumps, the faster the airflow , so the less will drop ( my thinking anyway )
Also, Surprised a planer thicknesser has a 50mm outlet - would doubling the input diameter reduce the amout of shavings hitting the walls of the seperator at any one moment in time, and therefore more will follow ?
 

keithy1959

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Raising the outlet hose in relation to the bottom of the top plate mights help too - mine are flush with the top lid.

FWIW, I stopped using my Thein baffles with the P/T and bought a cheap 4" chip extractor on the basis that its not much less volume (of chips), emptying is as quick if not quicker, and its a much shorter hose arrangement for 4" hose. I have 2 Thein systems using Kirby Vacuums in opposite corners in my workshop for everything else, and the extractor goes to the P/T whenever required.
 
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Raising the outlet hose in relation to the bottom of the top plate mights help too - mine are flush with the top lid.

FWIW, I stopped using my Thein baffles with the P/T and bought a cheap 4" chip extractor on the basis that its not much less volume (of chips), emptying is as quick if not quicker, and its a much shorter hose arrangement for 4" hose. I have 2 Thein systems using Kirby Vacuums in opposite corners in my workshop for everything else, and the extractor goes to the P/T whenever required.

Its not so much how long it takes to empty the Cam Vac, more the unpleasant fine dust. Emptying the Cyclone/Thien barrel is simply a matter of pouring it in to my garden waste bin (making sure it's only thicknesser shavings and nothing else). Where as with the cam vac, I need to get it into a black bag as it's a mix of everything, and you're messing around with the filter and all the fine dust that goes with it. Yes I do it outside and yes I wear a mask, but I'd still want to do it as infrequently as I can. Not every 30 mins like I need to when it's attached to the P/T.

I don't really mind if it's not super duper efficient. I'd be happy with 90%+
 

keithy1959

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The Kirby is up in the roof space to reduce noise. Scruffy as hell but it works !! Lots of Hot Melt glue and LX Tape !
Power is attached to the hose, and I use Neutrik Powercon connectors and CTS Vacuum adaptors, connected up to the auto-switch in the top picture.

IMG_20210830_112739.jpg

IMG_20210830_112615.jpg

IMG_20210830_112529.jpg
 

TominDales

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My vote would be with the deeper (and stronger) barrel suggestions. Either reinforce a plastic barrel or use a steel one.

Your Camvac system is a low volume high pressure dust extractor LVHP, your don't want to compromise that set up, so keep the pipes the same as the Camvac pipe diameter, going for wider pipes as used in the higher volume extractors HVLP would compromise your Camvac. Similarly you dont want to let more air into the barrell to stop it imploding, the vac needs to draw a vacuum.

The Camvac is sucking the debris out of the barrel because the debris is still moving at too high a velocity, the Thien spits it out at high rate. By having a deeper barrel then the particles will loose speed and fall to the bottom.

I guess you chose a Thein to be more compact, if you can a cyclone and a deeper barrel would be ideal, but a deeper barrel is a simple solution. No harm in reinforcing the barrel with internal wire or wood frame, this system is designed to pull a vacuum.
 
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I appricate that 100mm would be better, but my Thicknesser (Triton) and Planer (Triton) are both only 55mm.
 

TominDales

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I appricate that 100mm would be better, but my Thicknesser (Triton) and Planer (Triton) are both only 55mm.
100mm would give you less pressure drop over long runs, but given you have a Camvac 50mm hose, I'd stick with that or your could run into blockages along the lines. I'm sure a longer/taller barrel would help. you could try jerry-rigging a stout scrap box on top of your existing barrel with duck tape to give it a try before sourcing a deeper barrel to see if that cures the problem.
 

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