Who would buy a "Pentz" style Cyclone for £395

[Barry Burgess]

Jake your filters must cause a drop in suction as they are preventing the dust getting to the motors??? Don't forget I get no dust or chips anywhere near the filters and I have 40m2 of filter - a little more than you have.
Jake I an not agreeing that the 4" pipe is idea but that is what I had installed already. I have just acquired two lengths of 6" PVC piping from a roof rack(3.2M each) from one of our members. I will start making 4" & 6" Y type connections for the run to the machines. Once this is complete I will be able to check Bill's comments.
In the end its down to how efficient the hood at the machine is as well as the air speed.
With regard to the Canvac I said I checked it out when it had 2" hose before the 4" was used. I hope we can agree that 2" will not work???
Barry

 

[Jake]

Jake your filters must cause a drop in suction as they are preventing the dust getting to the motors???

To some degree, yes, but the effect is tiny compared to with a low pressure vacuum such as you are using. The static head, more suck, means that the air gets sucked through the filter regardless. Same as it does through a smaller dust collector hood, or a smaller pipe, etc. The resistances of those 'bottlenecks' are simply not anywhere near as important in a MVHP system such as the big camvac

Don't forget I get no dust or chips anywhere near the filters and I have 40m2 of filter - a little more than you have.

And I have much much more static pressure than you, so there!

Jake I an not agreeing that the 4" pipe is idea but that is what I had installed already. I have just acquired two lengths of 6" PVC piping from a roof rack(3.2M each) from one of our members. I will start making 4" & 6" Y type connections for the run to the machines. Once this is complete I will be able to check Bill's comments.

Excellent. I'm not decrying your system at all, btw. It's amazing. I'm just saying that 350CFM is 350CFM, whereever it comes from.

More is better, and what you do have is the ability to expand by upping pipe diameter. I can't add any more motors to my Camvac!

In the end its down to how efficient the hood at the machine is as well as the air speed.

Which is where I have another advantage over you - my high pressure means more that the machine's hoods do not reduce the airflow as much as they do for your low pressure system - so changing the hoods isn't so important. In other words, a higher proportion of my free-air flow is real-world flow at the collecting hood.

But for low pressure, yes, very much so - indeed doesn't BP say that all hoods need to be changed to 6" as well as the pipes?

With regard to the Canvac I said I checked it out when it had 2" hose before the 4" was used. I hope we can agree that 2" will not work???

I'd worry about it clogging on eg a planer, and I think it does reduce throughput significantly - although nothing like you'd imagine from a LVHP perspective, as again, the extra resistances involved just aren't as important. I have used mine with a reducer to a 2" hose on a router table, and the amount of air it whips through is still extraordinary. Of course, I use the bigger hose on anything with an appropriate duct.

 

[davy_owen_88]

Bill P was saying 4" pipe can support 350CFM throughput. Which is pretty much what a 3 motor Camvac does, and which you said wasn't good enough.

And he'd be right to say it isn't good enough. According to Bill 800CFM is needed for 'fine dust extraction' The keyword being 'fine' 100CFM is enough for chip collection (what my old RSDE1 moved), but to capture the fine dust 800 (or there about) is needed.

Cyclone or not is entirely irrelevant - the aim is to get XXXCFM at the machine and filtration to .5 microns or whatever.

That is true, but without a cyclone the filters will clog up and reduce that xxxCFM substantially. Even with a high pressure extractor the volume WILL decrease. The other thing is that high pressure + low filter surface area = more likely that very fine dust is being blown straight through the filters.

That said, the cyclone is an excellent way of keeping CFM up on a low pressure system where filter clogging has a disproportionate effect on the throughput figure. That doesn't mean that 350CFM to 0.5 micron with cyclone is any better than 350CFM to 0.5 micron without cyclone.

350CFM with or without a cyclone is exactly the same... before you start using it. 350CFM with a cyclone though will stay at 350 for a hell of a lot longer than it will without a cyclone because the filters will clog up and reduce that airflow.

And it doesn't mean that 350CFM isn't enough - it is just that there seem to be double standards here as to whether it is enough or not, dependent on the means of getting there. That doesn't make sense to me.

Enough for what though? Chip collection? Then sure its adequate. For fine dust collection? No chance. (and by that I mean collecting all the fine dust at the machine)

I use my Camvac right next to my machines with a 4', 4" hose, I can't see any dust in the exhaust air, and there is no way it could get through the three layer filter.

I have no doubt that the camvac is filtering everything it collects (I used a RSDE1 for about a year and that did the same) but that doesn't mean its collecting all the fine dust from the source which is where the 800CFM comes into play.

 

[Barry Burgess]

Jake most of my early work on cyclones was using a 2000W domestic vacuum and this is still the best for small hand tools but in the end I got tired of dragging the vacuum/cyclone from machine to machine. Now I have the whole workshop ducted with blastgates
I am making a cyclone for 2" piping at present to replace my existing cyclone like system. Its a down scaled version of my big cyclone with a diameter of 6". I am likely to use a high revving(10000 to 20000 RPM) industrial vacuum motor. I hope it will work if all the hand tools and possible a down draft table.
Barry

 

[Jake]

And he'd be right to say it isn't good enough. According to Bill 800CFM is needed for 'fine dust extraction' The keyword being 'fine' 100CFM is enough for chip collection (what my old RSDE1 moved), but to capture the fine dust 800 (or there about) is needed.

Barry has said that empirically his system works fine - by his 'lungs in the gym test'. And that's with 4" pipe and what BP says is therefore c350CFM.

That is true, but without a cyclone the filters will clog up and reduce that xxxCFM substantially.

With a LP extractor, yes, I agree.

Even with a high pressure extractor the volume WILL decrease.

A bit - not much. There is no discernable difference between a newly shaken out, filters changed camvac and one that is nearly full. That isn't the case for a normal extractor, for which I agree there is a marked difference between a clogged filter and a cleaned one.

The other thing is that high pressure + low filter surface area = more likely that very fine dust is being blown straight through the filters.

That's basically saying that Camvac's claim to achieve 0.5 micron filtering is a lie. You might be right - I can't test that. Seems a bit extreme to say that without any evidence, though. And it would have to suck the dust through three layers of filter, including a paper bag. Excuse me if I'm a bit sceptical about that.

350CFM with or without a cyclone is exactly the same... before you start using it. 350CFM with a cyclone though will stay at 350 for a hell of a lot longer than it will without a cyclone because the filters will clog up and reduce that airflow.

You are ignoring the massive difference in static pressure again.

Enough for what though? Chip collection? Then sure its adequate. For fine dust collection? No chance. (and by that I mean collecting all the fine dust at the machine)

Barry seems to think his works fine.

I have no doubt that the camvac is filtering everything it collects (I used a RSDE1 for about a year and that did the same) but that doesn't mean its collecting all the fine dust from the source which is where the 800CFM comes into play.

Are you seriously trying to compare a 3 motor camvac to an RSDE1?

My point is that Barry has said that he likes his system, with what BP says is a c350CFM throughput, and finds it entirely adequate. He also said the camvac was inadequate.

Fine, if you think the 800CFM is the requirement for you, forget the Camvac, it ain't going to do it for you. But if you are happy with a 4" pipe system, then you can't dismiss the Camvac.

 

[Barry Burgess]

Jake would you do me a big favour? I cannot load my cyclone in the car and come down to you. Could you load your Camvac and come out and pay me a visit and we both test the systems rather than debate all this airflow rates.
We can do some bucket of MDF dust tests and if you have shaving from a planer we could also test that and publish the results on the BB. Do some tests using the pipe work in my garage. etc
Barry

 

[Jake]

I re-read the old thread and saw I'd missed your acceptance of the dust bucket challenge! Let's go for that first?

 

[Barry Burgess]

I re-read the old thread and saw I'd missed your acceptance of the dust bucket challenge! Let's go for that first?

Why???
We will both learn the capabilities of both systems - both will have good and bad points thats for sure.
It should take only an hour or two. I am available 24/7 to suit your time.
What would be fairer??
Barry

 

[Jake]

It would be very fair, but I'm not sure I can be bothered to waste a day on it.

 

[Barry Burgess]

As Jake does not want to waste time on the test is there any other three or two motor Camvac users that could help with the test?
Barry

 

[davy_owen_88]

Like Barry I don't want to spend all my time arguing on a forum about what is the right and wrong way to go about good fine dust extraction. So I'll just respond to your statements and then I'll shut up. :lol:

Barry has said that empirically his system works fine - by his 'lungs in the gym test'. And that's with 4" pipe and what BP says is therefore 350CFM.

That may be the case, its a major improvement on what he had before, but its not the end of the ongoing struggle to get better dust extraction. As Barry has said hes upgrading parts of his system to 6" and I will bet my entire workshop that he will say its an improvement again. Simply because he wil have more airflow collecting more dust.

That's basically saying that Camvac's claim to achieve 0.5 micron filtering is a lie. You might be right - I can't test that. Seems a bit extreme to say that without any evidence, though. And it would have to suck the dust through three layers of filter, including a paper bag. Excuse me if I'm a bit sceptical about that.

My comment about high pressure and low filter surface area wasn't just pulled out of my ***...

increases the pressure which forces the fine silica (glass) particles that make wood strong to cut and tear their way through the fine filter strands soon leaving even a really good filter a useless sieve

You are ignoring the massive difference in static pressure again.

I'm not ignoring it, you are hiding behind it. I'm sorry but a higher pressure doesn't solve all the problems. It means you can pull xx amount of air through a smaller pipe than a lower pressure unit. But they don't make high pressure extractors (within a reasonable price) that move the amount of air really required. So high pressure doesn't solve anything.

Are you seriously trying to compare a 3 motor camvac to an RSDE1?

I'm not comparing them side by side, I'm saying they are both high presure extractors with tiny filters that don't move sufficient air to collect all the fine dust. What is the point of 0.5 micron filters when almost all the fine dust escapes the machine before being collected?

My point is that Barry has said that he likes his system, with what BP says is a 350CFM throughput, and finds it entirely adequate. He also said the camvac was inadequate.

Fine, if you think the 800CFM is the requirement for you, forget the Camvac, it ain't going to do it for you. But if you are happy with a 4" pipe system, then you can't dismiss the Camvac.

Well I do think that 800CFM should be the requirements for anyone who gives a damn about their health. I understand all these upgrades are expensive, and I'm not trying to say you should just stop everything and upgrade now, but you can't seriously expect me to believe that a camvac is all I'll ever need if I use 4" ducting.

 

[Jake]

Well I do think that 800CFM should be the requirements for anyone who gives a damn about their health.

Fine, go for it.

you can't seriously expect me to believe that a camvac is all I'll ever need if I use 4" ducting.

My point is no more and no less than this: if you are following the BP line, you can't ignore the fact that he thinks that 4" piping is good for c350CFM and no more with a low pressure extractor. So yes, you might as well use a big camvac, until you upgrade the pipe. It will give you that c350CFM anyway, and lose less at the collector hood.

Once you have 6" pipe in, you are up up and away, and can look down on the puny camvac with disdain.

 

[davy_owen_88]

My point is no more and no less than this: if you are following the BP line, you can't ignore the fact that he thinks that 4" piping is good for c350CFM and no more with a low pressure extractor. So yes, you might as well use a big camvac, until you upgrade the pipe. It will give you that c350CFM anyway, and lose less at the collector hood.

The thing is, a 3 motor camvac is more expensive than a 3HP low pressure extractor - and only moves 333CFM free airflow according to their site.

So even if you can only get 350CFM through 4" ducting (17cfm more than a camvac could possibly deliver), its cheaper, quieter and leaves the option to upgrade later if you don't get a camvac but get a 3HP extractor.

P.S I know I said I'd be quiet but that was before I realised the price on camvacs... :shock:

Anyway, I'm sorry if it seems like I'm just arguing for the sake of it, its just when you read through Bills website as much as I have trying to learn about all the details you come round to his way of thinking...

 

[Jake]

Davy,

I'm not arguing that the Camvac meets BP's requirements - it doesn't by a long way. All I'm saying is that no system with 4", according to BP himself, can do that.

Barry has always said that his cycloned system as it is with 4" pipe works well enough for him, and I believe him. As he put it, before, he had problems in the gym, after, he didn't.

However, BP's 800CFM is more than twice what BP says can be achieved by an cycloned HVLP on 4" pipe. In that context the 17CFM shortfall of a 3 motor camvac is utterly irrelevant. Put it this way, one gives you 43% of what you need if you take BP at his word. The other gives you 41%.

My point is simply that you can't pick and choose - if you want to follow the BP line to the letter, you have to install 6" plus pipe. If you don't, you aren't going to achieve 800CFM, and you can't call other extractors which also have about 40% of the required throughput inadequate while holding your own up as still being adequate.

Re cost - sure, pricey - don't believe list prices though, factor in the lack of need for pipe (they are easy to wheel from machine to machine, and short enough not to get in the way), deduct extra cartridge filters, and the cost of a cyclone or materials and time to make one, and it's not looking so simple.

 

[Barry Burgess]

Jake make my day and spend a few hours testing your's and mine theory in practice. The shorter the run then more my 6" connection comes into play( from the filter to the impellor to the top of the cyclone - be aware)
Barry

 

[Jake]

By the time I've driven out there and back that's a whole day, and I have better things to do. I don't mind chewing the fat, or spending 20 minutes doing some test and writing it up, but I'm too busy doing up a house at weekends to spend a day out on this. Sorry.

I don't actually see what it is going to prove anyway. Or that it is particularly relevant how the camvac works on your piped system - one of its advantages, to me, is that you don't really need one 'cos it is portable and short.

The real point is go with 6" pipe if you want 800CFM, which it sounds like you are about to do. Good for you!

 

[Anonymous]

Take a look team - this is what you need to remove every bit of dust prior to it hitting the filters

Any comments !!!!

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[Barry Burgess]

Looks totally professional to me - well done hope it did not cost too much.
Just one question how do you clear any blockages with the top fixed??
Barry

 

[Barry Burgess]

Just a few other comments. You can get a 200 mm slow bend from CCL for £21.31 +VAT but you will have to make a new plate for your impellor outlet as most are 150mm maximum. 200mm flexible could cost an arm and a leg. Also check your motor with a clamp meter as the 200mm impellor outlet might cause a load problem with the motor. You will have to modify 150mm flexible to connect your cyclone to the dust collector.
Barry

 

[Barry Burgess]

Look whats for sale on eBay?
link