Who has achieved 1000cfm at their static machines (a la Bill Pentz).. if so, how?

[Togalosh]

Hello Gents

I would like anyone's buying & fabrication experiences/ knowledge on how they achieved 1000cfm at their machines & how they verified/ tested it.

My workshop build has ground to a halt now that I have to wage a war on dust, which has me sneezing within 15 minutes of going in. I've only set up basic, makeshift extraction while getting things inplace but I now realise that my old UK set-up was woefully inadequate having spent the time really getting into Bill Pentz's website & therefore there is no point in installing my old kit again.

As an ex catering "engineer" (not my term.. technician is more accurate) I have some previous extraction knowledge & think that I have a pretty good understanding of what is needed.. What I am struggling with is getting something set up at a more reasonable price than importing a ClearVue system. I have a good manometer & a cheapo anemometer & this weekend I have discovered an amazing facility in a nearby town - a funky community centre with many 3D printers, a cnc plasma cutter, a cnc laser cutter & other machines besides so I may just have a reasonable chance of fabricating kit for myself. I realise that making impellers is fraught with danger but I cannot find a fan blade supplier.

As ever any help & advice will be greatly appreciated.
Togs

 

[baldkev]

Hi.... ive had a lot of very useful info from @Inspector ( pete ) and it boils down to a big impeller, 14" or so, plus at minimum 6" ducting, 8 is better .
The more knowledgeable guys will be asking: what is the power source ( single / 3 phase ) , what machines are you using, how many machines do you run at a time, what duct length / run you will have and us the machine venting outside or into bags etc inside?

 

[Cabinetman]

Don’t know the cfm is but it’s a lot and you have to be careful what you put near the end of a hose.
This is my setup, the ducting is 12” at the motor end, it then reduces as it gets further away.
As you can see it’s a three bag job, the impeller is made from 6mm plate and is bolted on the end of a 3 phase motor, not very sophisticated. The ducting terminates just above the impeller.I have sketched it here it’s about 12” in diameter with I think 6 vanes that stand up about 3 or 4”. How you would balance it if you had one made I don’t know, sorry. Btw the full setup was £450 second hand as I’m told people don’t want them. I do know my local refurbished woodwork equipment place doesn’t touch them either.
It would be better obviously if it wasn’t in my workshop but I didn’t have any choice about it. Ian

 

[Inspector]

Static balancing is all that is usually done. A stub shaft is usually put into the impeller and placed on a pair of knife edges that are parallel and level. The heavy side of the impeller will end up at the lowest point. A shallow hole is started with a 12mm or bigger drill to remove a bit of metal. The process is repeated until the impeller doesn’t move.

Out of curiosity I called a couple places to see what dynamic balancing would cost and was quoted $300+Can. So I doubt anybody does it for impellers in the size ranges of any smaller businesses or shops we would have.

Pete

 

[Togalosh]

Hi Baldkev,

I have 3ph & I will get whatever size ducting (PVC pipe) I need. My workshop is 4.7m x 6.4m.. I think .. with a sloping ceiling giving decent height at one end. So far I have placed all machines in the lower end/half while my bench & assembly space is at the window end. I work alone so only need 1 machine running at a time& if blast gates are easily accessible then that would help. I could vent outside but then I'd loose the benefit of me spending a King's ransom of decent insulation.. Bill Pentz shows a diverter wye option for both venting inside & outside.

I have the usual set up of a 1/2 decent workshop (3ph bandsaw, medium sized moveable PT with a dream to go static, RAW, good sized TS, Lathe, Router table, a planned downdraft table, Pillar drill & table top sander). I thought the RAW, sander & maybe even the Router could all be hooked up to a shop vac ?

I have a good sized commercial kitchen input air fan which I had boxed in with 2 stage filtration as a massive air scrubber bt that motor isn't appropriate for for dust & chip handling I believe.

Cabinetman, that looks good to me - where did you get it from Ebay & a local shop ? Ebay UK is much, much better than Leboncoin or Ebay Fr.. the French don't sell many bargains. .. or maybe I haven't been looking propely.

Inspector, Have you a photo or sketch of the pair of knives balancing incase I cannot find it online?

Thanks all !

Togs

 

[Yojevol]

I have to wage a war on dust, which has me sneezing within 15 minutes of going in.

Going back to your original statement, are you saying that you're sneezing 15mins after entering the workshop after any dust has settled overnight or 15mins after start of machining? If it's the former then you've got a real problem which is not going to be easily solved by a more powerful extraction system. It may be that you've got to consider PPE.
Most of the fine dust which escapes the extraction system is caused by poor design of the ducting and baffling inside the m/c. Have a look at Steve Maskery's attempt to improve things on his bandsaw. Sanding machines are naturally the worst offenders.
Brian

 

[Cabinetman]

Hi Baldkev,

I have 3ph & I will get whatever size ducting (PVC pipe) I need. My workshop is 4.7m x 6.4m.. I think .. with a sloping ceiling giving decent height at one end. So far I have placed all machines in the lower end/half while my bench & assembly space is at the window end. I work alone so only need 1 machine running at a time& if blast gates are easily accessible then that would help. I could vent outside but then I'd loose the benefit of me spending a King's ransom of decent insulation.. Bill Pentz shows a diverter wye option for both venting inside & outside.

I have the usual set up of a 1/2 decent workshop (3ph bandsaw, medium sized moveable PT with a dream to go static, RAW, good sized TS, Lathe, Router table, a planned downdraft table, Pillar drill & table top sander). I thought the RAW, sander & maybe even the Router could all be hooked up to a shop vac ?

I have a good sized commercial kitchen input air fan which I had boxed in with 2 stage filtration as a massive air scrubber bt that motor isn't appropriate for for dust & chip handling I believe.

View attachment 117745

Cabinetman, that looks good to me - where did you get it from Ebay & a local shop ? Ebay UK is much, much better than Leboncoin or Ebay Fr.. the French don't sell many bargains. .. or maybe I haven't been looking propely.

Inspector, Have you a photo or sketch of the pair of knives balancing incase I cannot find it online?

Thanks all !

Togs

It was 10 years ago now and it was a small ad in the local paper, an old guy was selling up and closing down his workshop, it was an incredible dusty job to strip it all down, get it all out and loaded on the trailer then back to my workshop, The daft thing was that I was a couple of lengths short plus a couple of blast gates and a swept joint I believe and they cost as much again as the whole thing had!

 

[baldkev]

How you would balance it if you had one made I don’t know, sorry

On my impeller there are a couple of 'additions ' so rather than remove material to balance, they added.
My donor was a fercell 3 bag unit.... and nice workshop!!


@Togalosh sounds like 6" pipe would do, again, 8" is better if the impeller etc is up to it. When i finally do mine it'll be 8" main pipe with 6" branches i think.

 

[Togalosh]

Brian; I am sneezing & sniffling as I have not set up anything like a decent system while I'm still installing my workshop (I don't want to waste cash on kit which I won't need once I work out what I need & get it, nor cut up existing gear to make it fit a temporary set up). My RAW, a sander & wishful thinking/ wrong approach so far are the main offenders. Back in Brum I was battling with the same issue on a much smaller scale even after spending a small fortune on Axi ducting etc & doing my best to follow all advice. I now realise that I haven't even got a decent blower/ vac so I have never had a chance of having a healthy set up.. & I should not wait any longer to sort it out properly. Also I have a good 3m mask but even in my cooler workshop it's still to warm to wear it comfortably.., excuses, excuses.

Cabinetman, I have seen rivets on blades before. Is that impeller loud ? I was hoping to get a backward curved blade but obviously that will be more than tricky to make & get right ..or buy. I now have access to all the tools & machines but little metalworking experience.

I have seen some used kit for sale at good prices but it's all up north .. 800+ km away. The blower is 1 hurdle but getting a proper size & efficient cyclone is a bigger one.

There is plenty of space to have an exterior blower/ system but that would involve a conversation with my father-in-law which I would rather not have. The less said is definitely better.. but it's tempting.

 

[baldkev]

I havent got the impeller/ system set u0 yet.

As for cyclone, if you can vent the dust to an outside shed, you wont need a cyclone. Just filters up high in the shed to reduce external mess

 

[sploo]

I bought a 3hp Fox F50 843 (for the motor/impeller unit only) and integrated that into a ducting set up for my old workshop. That might be a cheap way of getting a reasonable blower.

Baldkev makes an interesting point; as a cyclone does rob you of airflow. I did the same - no cyclone, and an external "shed", into which the dust blew. Made a heck of a mess, but that mess was outside the workshop, and I always wore a powered respirator when emptying it.

If you have the ceiling height then a DIY cyclone would be ideal; as in the temperate months you can just vent the exhaust outside, and return the air into the workshop via a filter stack during the colder months.

An important consideration is also the air speed in the ducting; and going too wide (with an inadequate blower) can drop the air speed; such that it cannot carry the dust.

As already noted in the thread; one big problem is that a lot of machines have poor collection at source, so even with a good extractor it's hard to capture everything. A powered respirator (e.g. the Trend Airshield) and workshop air filters can go a long way to keeping you safe.

 

[Togalosh]

I realise that I have some calculations to do to get a system specification's correct ... I was a gas "engineer" with commercial & industrial pipework tickets until recently so I am used to working out pipework sizing but this is not quite the same. If I don't have air resistance data to work from how can I calculate my requirements? Could I deduce from steel ducting data? It's €89 per 4m length of plastic 200mm/8" & €54 for 160mm/6 1/4" so maybe metal is cheaper. More research to do.

So where do you start ?...1st with duct length & required air speed plus resistance of elbows & blastgates which = m3/hr at blower. Then that gives you duct size, which gives impeller size, motor rpm & wattage/ hp.?.. or with motor & impeller ?

There's next to no temperate climate here (the seasons change within a few weeks ) & that's when the farm work is relentless. Venting outside is really tempting though as it takes out a lot of head scratching & expense. I could build a slatted shed with bin at the bottom.. but it would be a wildlife haven.

Sploo: What size impeller is your Fox's?

HHmmm ???
I could just keep it simple &
follow Bill's advice (as he has a workshop layout for a 2 car garage) & get a 5HP motor with a 15" impeller & install an 8" main with 6" drops... somehow I just need to make/buy an impeller, buy/make a decent cyclone, the rest is relatively straight forward.

 

[Sachakins]

5hp motor on 220-240v draws 28amps

See this chart

http://www.elliottelectric.com/Stat...calTables/Amperes_Single_Phase_Alternate.aspx

 

[baldkev]

I was considering trying to take a mould of my impeller and bash out copies.... but not sure how well I'd do. If casting aluminium, the mould would have to be heat proof, and i would imagine find a suitable aluminium alloy

 

[Inspector]

Motor amperage differs from one motor to the next and the way it is used. I have a 5hp air compressor that is 29 amps but the Leeson motor on a 5 Hp ClearVue is just about 21 amps. It needs a 30 amp circuit breaker though. Likely to handle the amperage surge at startup.
Pete

Leeson Single Phase Motor Information

• 5 HP, 230 V
• 20.8 FLA - requires 30A breaker.

 

[Inspector]

Togalosh next week when I get a chance I’ll send you a link to an online calculator that will help you play what if scenarios. You plug in the sizes of duct, lengths, CFM, elbows, duct entrances etc and it will give you the static pressure loss, airspeed and a bunch more.

Pete

 

[Togalosh]

A 1ph motor is not an option.. all my calculations showed 5Hp ws 20.7... & @ 3ph ="4A.

Is the higher amp drawer due to efficiency/ inefficiency ..or they don't take load into the calculations.?

It all adds up & I need to keep the power demand down. I should also install a consumption meter.

Bill Pentz strongly advises against aluminium impellers due to fire risk following debris hits- esp from rusty metal objects accidentally sucked up. He likens it to a sparkler going off... they are made of aluminum thingumybob. Perhaps trying to 3D print one using the stronger types of plastic (eg with chopped up stiffners incorporated) but the velocity of the impeller makes for double scary failures. He who dares wins .. or goes to A&E.

He also says there are much better impeller designs (for efficiency) than what he uses but they are highly inappropriate for dust & chip handling as they jam/ block/ trap shavings & strings & easily shake themselves to bits & kill motors.

Pete, that calculator would be ace.

Again. Thanks very much.

 

[heimlaga]

I built what essentially my own version of the largest size Clear Vue system. Welded up a cyklone from 2mm plate to Bill Petz drawings. Scrap yard materials cut out with angle grinder and welded together using my trusty 1960-ies Unitor stick welder. Bought an old 4kW 400 volt three phase industrial dust blower from a scrap dealer and rebuilt it. Built a filter cabinet that hold three cartridges with roughly the same filter specification as those Clear Vue uses but with much larger filter surface which means less pressure difference and hence less filter wear and better filtering of small particles.
In summer I open one blast gate and close another to dump the exhaust air outside. In winter it goes into the filter cabinet.


Most of the ducting is secondhand spiral ducting scavenged from various demolition sites and scrap yards and dumpsters. The main line is 160mm and now I am little by little upsizing the dust ports of my machines to either 120 or 160 mm depending on what I think is needed. I have made most blast gates myself.
This has all been a lot f work but when comparing it to the cost of a commercially available system I rekon I got a decent hourly pay.

However I ended up on a two and a half month sick leave with fatigue. Everything went well until in midst of the dust collector project we got a severe storm and suddenly I had around 100 windfallen trees to clear up and process to firewood and timber. We sawed 120 logs and I barked some 65 logs more for a round log wood shed and the firewood stacks total over 20 metres in lenght on an height of 1,8 metres and width of 1 metre.
In midst of clearing up that I ended up in a collision with my car (not my fault) and got conned by the workshop and stood there with an unusable car and no insurance money. The car was 24mm shorter on one side then on the other so I had to straighten the frame and beat some panels back to shape as best I could and fetch a new bonnet and bumper from a scrap yard far away and do quite a bit of repainting. In midst of that I got a breakdown on the logging winch and had to rebuild it completely and after a few minutes of work with my newly rebuilt winch an engine breakdown on the tractor and had to spend quite a bit of time repairing that. Not to mention the breakdown and subsequent repair of the welder in midst of rebuilding the winch because my father did most of the repir work on the welder and the second breakdown on the tractor engine which a friend helped me repair. And....all that in midst of some severe health problems in the household that had to be taken care of.
All that had to be done in my spare time besides two part time jobs and with customers waiting for me to get the worshop going with the new dust collector. So....conclusion...... building a dust collector from scratch without adequate time on hand is nothing I would recommend to anyone but a few of my worst enemies....... but if you have the time just build it.

 

[Togalosh]

Hello Heimlaga, nice set up ... do you still have the cyclone plans you can send me please ? I couldn't find it on Bill's website - a lot of the links are now 404... no, I 've just found it. Doh.

Can you show us your filter set up too, if you don't mind ?

Although it's not nice to hear that you have such troubles it does help to keep my own in perspective.

 

[MikeK]

I built what essentially my own version of the largest size Clear Vue system. Welded up a cyklone from 2mm plate to Bill Petz drawings. Scrap yard materials cut out with angle grinder and welded together using my trusty 1960-ies Unitor stick welder. Bought an old 4kW 400 volt three phase industrial dust blower from a scrap dealer and rebuilt it. Built a filter cabinet that hold three cartridges with roughly the same filter specification as those Clear Vue uses but with much larger filter surface which means less pressure difference and hence less filter wear and better filtering of small particles.

That is an impressive system! If I had the ceiling height in my basement, I would buy or make a similar system. I had an opportunity to buy a 4kW 400V industrial blower still in the original box for €100, but the overall dimension of the motor and impeller housing was too much to be useful in my shop. It was like passing up an offer on a nearly free Aston Martin DB9 because it wouldn't fit in the garage, but I would never be able to use the blower.