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Pentz cyclone questions

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Sachakins

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@Sachakins mentioned Gyro type dust collectors/separators, which prompted me to go back and take a look at the Harvey/Axminster G700. I was quite impressed when I saw the capacity as 1110cfm with 6" ducting ... but this is then contradicted when you scroll down to graph slightly further on, which shows machine maxes out at ~750cfm, rough guess will deliver perhaps up to 600cfm with the sort of set up I expect to have ... which isn't really enough for 6" duct. The bigger Gyro collectors don't have graphs ... but if there's a single message I've taken from the Pentz site it's not to buy an extractor without studying the graph.

Back in the cyclone world, overnight I sent out a few requests to industrial suppliers to quote for material moving fan able to deliver 2000 m3/h at 2500Pa (1150cfm at 10" pressure): this looks like the best route, I am getting helpful replies.
Did you scan through the g800 spec also,
Static Pressure5,200 Pa
Airflow1,550 m³/hr @ 125 mm / 2,200 m³/hr @ 150mm
 

Inspector

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Baldkev was in a similar hunt last year and I found a Japanese company on Alibaba that make to order. They started a conversation but I don't know why it didn't work out. You could see what they have to say.

Pete
 

heimlaga

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I built my Pentz style cyclone from 2mm plate but that was because I stick welded everything and because I used ordinary mild steel plate. Industrial cyklones are often built from 2mm plate so they don't rust and wear through. A thin walled mild steel cyklone would wear out quickly in industrial use. Bill Pentz's designs from 0.6mm sheets are obviously not intenmded for professional use.
If you use stainless which will be affected only by wear and not by rust I rekon 1,5mm should be thick enough even in professional use.

I actually used 1,5mm plate for the cone so it would be easier to shape. There is apparently less wear on the cone than on the parts higher up. I did stick weld it together but I would have gone daft if I had tried to stick weld everything from 1,5mm plate.
Professionals usually have mig welders which work better on thin materials.

They say an amateur cannot shape materials in theese thicknesses. The fabrication shop next door rolled the cylindrical parts for me. I did the rest of the shaping myself. No problem.

I bought two fans from a local scrap dealer. Used one. The other is in a hay shed out in the woods where I keep my spare parts store.

I made the cylinder and the cone with flanges so that the cone can be unbolted for access. When assembling and welding the parts together I found that thanks to the rigid flanges it became a lot easier to get everything round and smooth. Looking back I am almost certain that it would have been more laborious and difficult to make a flangeless one piece cyclone.
 
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Sachakins

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Just in case you are looking for duct suppliers, I've used these in past for various extraction bits and bobs and pipe.

 

JoshD

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I built my Pentz style cyclone from 2mm plate but that was because I stick welded everything and because I used ordinary mild steel plate. Industrial cyklones are often built from 2mm plate so they don't rust and wear through. A thin walled mild steel cyklone would wear out quickly in industrial use. Bill Pentz's designs from 0.6mm sheets are obviously not intenmded for professional use.
If you use stainless which will be affected only by wear and not by rust I rekon 1,5mm should be thick enough even in professional use.

I actually used 1,5mm plate for the cone so it would be easier to shape. There is apparently less wear on the cone than on the parts higher up. I did stick weld it together but I would have gone daft if I had tried to stick weld everything from 1,5mm plate.
Professionals usually have mig welders which work better on thin materials.

They say an amateur cannot shape materials in theese thicknesses. The fabrication shop next door rolled the cylindrical parts for me. I did the rest of the shaping myself. No problem.

I bought two fans from a local scrap dealer. Used one. The other is in a hay shed out in the woods where I keep my spare parts store.

I made the cylinder and the cone with flanges so that the cone can be unbolted for access. When assembling and welding the parts together I found that thanks to the rigid flanges it became a lot easier to get everything round and smooth. Looking back I am almost certain that it would have been more laborious and difficult to make a flangeless one piece cyclone.
Thanks @heimlaga!
 

JoshD

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OK, starting to get replies back from industrial suppliers. Mostly around £1600 (although one at £4000, fan alone weighs 270kg). So far nothing quite hits the spot: I asked for material handling fan capable of 2000m3/h at 2500Pa (1150cfm at 10" pressure), and that seems to generally get me into the 4kW rather than 3kW territory ... but at that point motors are mostly 400/690V, not 230/400. There was one (Soler Palau CBT160) that looked like it might be OK but impeller is aluminium (Pentz says this is a no-no); supplier is able to change to steel, but now needs full description. I may be overthinking it but I suspect ATEX compliance is going to be tricky: fan ought to be ATEX compliant if used for wood dust, but I suspect I will need to demonstrate ATEX compliance of whole system, and I daresay I will need to be qualified ATEX designer .....

This is all making the forward-curved fan I posted photos of look quite good; but will I think be very noisy---and those blades look like they they could easily
snag any shavings; or alternatively there are numerous backward-curving closed impeller options out there, which should be OK provided cyclone does its job and bin is regularly emptied.

I emailed Bill Pentz a few days ago, before posting on the forum, but no reply from him. And nothing back from Axminster---I asked for graph for Gyro G800 ....
 

JoshD

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And now the ATEX question has me thinking about the whole question of commercial safety standards: I have Parkinsons Disease and also major back problems (resulting in lumbar spinal fusion L2-S1), and my wife would like me to find a local 16y-old who would just come by on Saturdays to help me keep the place clean and tidy ... but I don't think I can do that unless I can give him air safe to breath and no risk of being blown up .....
 

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Please keep going with this thread as I'm interested in your findings.

I have a conventional extraction system with bag-type extractor
IMG_6153.jpg

which I don't use as much as I would (should) like as it is so noisy. It was suggested that I move it outside, but the workshop is heated and sucking all the warm air out does not appeal.

The noise comes mainly from the impeller, which is a flat-bladed steel type driven by a 0.9hp 3-phase motor. I would like to build a cyclone unit (the little one in the photo works brilliantly) but sourcing a robust impeller that is significantly quieter is proving to be a challenge.

Are you getting any noise metrics from impeller suppliers?
 

TheTiddles

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What are you aiming to achieve here? Do you want an extractor so you can get woodworking, or are you fancying making a custom extraction system? You can do both, but you will spend a long time doing the first part and maybe not get to the second.

I love fluid mechanics, I really do, my extractor is a 14-year old 1.5kW Axminster one with a fine filter cartridge and a lashed up connection to some soil pipe that I know is causing a lot more pressure drop than necessary, it’s been there for 10+ years, because I’d rather make things, than things to make things.
 

JoshD

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What are you aiming to achieve here? Do you want an extractor so you can get woodworking, or are you fancying making a custom extraction system? You can do both, but you will spend a long time doing the first part and maybe not get to the second.

I love fluid mechanics, I really do, my extractor is a 14-year old 1.5kW Axminster one with a fine filter cartridge and a lashed up connection to some soil pipe that I know is causing a lot more pressure drop than necessary, it’s been there for 10+ years, because I’d rather make things, than things to make things.
You know what, you're so right. I've been coming round to this view since this morning. It's getting way too difficult and complicated ... largely because of the cyclone. On Pentz's numbers, take the cyclone out, the pressure drops then, and the job is then easily done by a 2-3kW coarse filter bagging unit, placed outside. OK there's a filter to clean from time to time, but it leaves thousands free for kit I actually want ....

What's more if I bought a quality 3kW unit (eg Felder FA22) I could always fit a cyclone upstream afterwards if the urge takes me ....
 

heimlaga

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An oil barrel is good enough for an outdoors cyklone.

It is when you use fine particle cartridge filters that you need a good cyklone before the filters in order to catch as much dust as possible and reduce the wear on the filters.

I used a standard bag over bag dust collector in the past. In practice it was nothing but a chip collector spewing out fine airborne dust throgh the filters. I got problems with my sinuses and eyes and was told that it may be a prelude to a dust allergy. I cannot afford to get an allergy that would make it impossible for me to work in any trade where I have at least some competence.
Therefore I built a good dust collector. Got rid of all the sinus and eye problems at once.
 
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JoshD

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@heimlaga I'm having eye problems myself, and I don't like to think what's happening to my lungs. I'm envisaging coarse filter bagging unit in acoustically-insulated lean-to outside workshop, venting to outside world via baffles. Will wear a respirator to empty. If you believe Pentz then cyclone/separator adds 2.25-4.5" pressure (oil barrel is effectively trashcan separator and is worse than cyclone). Having done a fair bit of reading/thinking/googling, this 2.25-4.5" extra pressure is a real headache: without it I reckon I can build ducting to supply 1000cfm around 6"-8" pressure, a bit less if necessary; this is within the realm of affordable available kit; but when you start asking for 1000cfm at say 10" pressure you enter a whole new world of bespoke/specialist hardware. Conclusion I've reached: I can't have the Pentz cyclone without the Pentz fan ... and I'm not happy to make my own fan. I could import ClearVue cyclone ... but I expect that will end up costing the same as a Gyro G800 ....
 

heimlaga

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If there was a way to bring it to Norfolk on the cheap I think I could supply a reasonably priced fan. It is belt driven so any motor could be fitted. There is a hole in the housing left by the scrapyard grapple but it could be repaired by welding in a patch. The ball bearings have to be shifted of cause.

However in reality I think you should look for a secondhand industrial fan in the UK. They aren't that hard to find. If I had bought every one that I come across I would have filled half a barn by now.
 

Sachakins

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@heimlaga I'm having eye problems myself, and I don't like to think what's happening to my lungs. I'm envisaging coarse filter bagging unit in acoustically-insulated lean-to outside workshop, venting to outside world via baffles. Will wear a respirator to empty. If you believe Pentz then cyclone/separator adds 2.25-4.5" pressure (oil barrel is effectively trashcan separator and is worse than cyclone). Having done a fair bit of reading/thinking/googling, this 2.25-4.5" extra pressure is a real headache: without it I reckon I can build ducting to supply 1000cfm around 6"-8" pressure, a bit less if necessary; this is within the realm of affordable available kit; but when you start asking for 1000cfm at say 10" pressure you enter a whole new world of bespoke/specialist hardware. Conclusion I've reached: I can't have the Pentz cyclone without the Pentz fan ... and I'm not happy to make my own fan. I could import ClearVue cyclone ... but I expect that will end up costing the same as a Gyro G800 ....
It sounds so daunting to achieve the Bill Pentz ideal motor/fan/cyclone/ducting.
That was the conclusion I came to. But then I'm a hobby turner, not a commercial workshop and no intention of ruining my hobby for commercial pressure.
If you are going down the route of a commercial workshop, I would put the entire design/specification/build/install into the hands of specialised extraction designers, making it their responsibility to achieve a certified system that will pass Health and Safety inspection/compliance/certification.
Would think that would be minimum to satisfy insurance.

You could also take the approach of having it built outside, into an insulated/sound proof annex, then after the system handles the main load, you add a secondary fan system to pump the exhaust through another set of filters/water scrubbers then that highly cleaned warm air is then piped back into workshop, keeping you toastie and reduced heating cost.

Just a thought/broad idea suggestion.
Cheers
 

TheTiddles

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Cyclone separation has been around for about 140 years, Bill Pentz’s stuff has been available for 20+ years? Most commercially available extraction systems don’t seem to conform to his apparent highly important characteristics. At least in the UK, companies would have problems if what they have been buying was unable to do the necessary job.

I’m not saying he’s wrong, but it doesn’t look like his ideals are particularly important for the purposes of having an extractor for woodwork, at least.
 

heimlaga

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The difference between cyklone and cyklone boils down to how high percentage of how small particles will it catch.
Some cyclones are actually intentionally designed to let the small particles through. For instance of you want dust free planer shavings that can be sold to horse owners at a higher price.
Others aren't designed at all. Larger businesses generally blow the exhaust air outside anyway so they do not care whether their cyclone is efficient or not. Those who recycle the warm air often hae extensive filter units so if the cyklone picks upp the larger bits it is all right.
 

JBaz

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What's more if I bought a quality 3kW unit (eg Felder FA22) I could always fit a cyclone upstream afterwards if the urge takes me ....
I had thought of just adding a cyclone to my system, but all the designs I've seen have the cyclone on the "suck" side of the impeller. This would require a new rigid bin which would receive most of the dust and shavings, leaving very little for the current bag. Then retaining the same dust filter would produce the same air quality as now.

My issue is mainly the noise, so retaining the same impeller (the main source of the noise) wouldn't reduce it, so I would be nearly doubling the size of the extractor system (space is a consideration) for very little gain.

I concluded that just adding a cyclone to a conventional extractor system wasn't really a flyer.
 
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