Building The Dust Extractor System

[BobL]

. . . . . .I hope this helps exlain

Thanks for that.

A couple of other matters you may need to consider.

A 2HP motor turning even a 400 mm diameter impeller @1450 rpm will not generate enough pressure to move sufficient air through machines and ducting.
To move enough air, 2850 rpm or preferably 3600 rpm will be needed.
However, if a 2HP/2850rpm motor is used on a 400 mm impeller it will grab too much air and overload/overheat the motor.
A 2HP/2850RPM motor is limited to driving about a 12" impeller.

To drive a 400 mm impeller without overheating the motor you will need a 4 or 5HP motor.

[Opelblues2]

Hi BobL and all others

in your post you have stated RPM for motors and then fan RPM, As I'm just starting on that learning curve in relation to rpm, now the unit I have in operation at the moment is a belt drive, and was in operation at a Laundry to remove the hot air from the drier room
On this unit the pulley on the motor is 100mm @ possible RPM of 1450, the pulley on the blower unit is 250mm @ possible RPM of 580 at the shaft. and tip speed is completely different Calculations again.

Reduction Drive / Belt Drive
if I was going too use this type of drive, with the current pulley setup I would need to upgrade to a synchronous three phase AC rated at 7000 rpm to be able to give a rpm on the blower of 2800rpm, as this is not possible on my budget a single phase electric motor is the way I need to go.

Geared Drive this is way out of my budget. so forget it

Direct Drive
This seams to be the simplest form, IE the blower is connected directly to the motor thus if the motor drive shaft can turn at 2800rpm then the blower will run at this speed as well, now my understanding is a single phase motor will turn a 400mm disk with out a problem as it is working against is the weight and the friction of the air against the disk but as you add resistance like adding a paddle (I will call it) the more force, could I call that "horse power or torque" is required

now could go an build a impeller like some have built out of ply, and then post it on YouTube. sorry that's not even in my dreams or nightmares. That is why I left this part, the design of the impeller to the expert. I gave mark the length of the longest run the size of pipe. I just gave him all the drawings that I have done and he did the rest, as he sad it was good change from the stuff he has been doing for the last 6 years, the only parts from the second blower that will be used re the main shaft and the pillow blocks, the blower is also placed after the cyclone and filters so impact will be nil, no sparking danger.

the last blower unit I did look at is the type of unit that is on the waste transfer trucks I drive. now it is a twin concentric rotary vane blower at 85lt per second @ 4000rpm operation on a 125mm draw point, the back pressure doesn't change as I understand. i don't know anymore other than it just sucks and keep on sucking until the tank is full. Cost $15000

[BobL]

Hi BobL and all others
in your post you have stated RPM for motors and then fan RPM, As I'm just starting on that learning curve in relation to rpm, now the unit I have in operation at the moment is a belt drive, and was in operation at a Laundry to remove the hot air from the drier room

That sounds like a good use for this type of setup

On this unit the pulley on the motor is 100mm @ possible RPM of 1450, the pulley on the blower unit is 250mm @ possible RPM of 580 at the shaft. and tip speed is completely different Calculations again.

It's 580 RPM whether its at the shaft or the tip. That's a typical RPM for these sorts of fans. My squirrel cage fans run from zero to 1730 rpm. Above that the don't work so well.

]Reduction Drive / Belt Drive
if I was going too use this type of drive, with the current pulley setup I would need to upgrade to a synchronous three phase AC rated at 7000 rpm to be able to give a rpm on the blower of 2800rpm, as this is not possible on my budget a single phase electric motor is the way I need to go.

You could simply reverse the pulleys which would give you 3625RPM but
1) the load on the motor will probably be too high and burn the motor out
2) The fan efficiency would not be as good as an impeller at that speed.
3) The bearings on the fan end might suffer as you will be asking them to run 5x above their original speed.

Direct Drive
This seams to be the simplest form, IE the blower is connected directly to the motor thus if the motor drive shaft can turn at 2800rpm then the blower will run at this speed as well, now my understanding is a single phase motor will turn a 400mm disk with out a problem as it is working against is the weight and the friction of the air against the disk but as you add resistance like adding a paddle (I will call it) the more force, could I call that "horse power or torque" is required

It depends what you mean by adding resistance. Fans/Motors are counter - intuitive, adding another paddle will increases the ability of the impeller to grab more air which means the motor has to do more work to turn the impeller and so will draw more current to maintain its RPM. Too large an impeller on too small a motor will lead to motor burn out. It's like trying to ask a 1000cc motor to move a 10 ton truck.

OTOH, blocking the flow by ducting, filter bags, cyclones or connecting the ducting to machinery adds back pressure and I also call this "resistance" but now this impedes the ability of the impeller to move air. As it is now moving less air it does less work and draws less current.

now could go an build a impeller like some have built out of ply, and then post it on YouTube. sorry that's not even in my dreams or nightmares.

There's nothing wrong with ply, it has after all used been used successfully for propellers, it depends how it is built. In general it's suitable for lower RPMs or else the impeller has to be built like a brick outhouse which is not practical for DIY workshop dust extraction.

Assuming the 400 mm diameter impeller is a conventional design then there is not way they can be turned with anything less than a 4HP motor. If the impeller is derated the it should be made smaller to suit the motor.

[Opelblues2]

Hi all.
wow the views on this subject has really surprised me, I didn't expect that amount of people would read this post. now the cyclone system has been in operation around three months and what I should have stated at beginning of the post is that the whole system has been and was setup and built with the limited recourses at the time.
Now the squirrel cage bower was a stop gap solution and what I had on hand at the time, it is under powered, the wrong type of fan configuration, moves too low of a CFM to scrub all the air from the tool stations or the sounding air at any of the open points in the container, but what it does do at this stage is remove some of the dust/chips to keep council "local law" officer happy and put the wind up the next door neighbours as this is were the problem started.

as one had companied to the council about the dust from my woodworking was affecting their health, after complaining that the dogs ate there chickens, after complaining that my daughter played her music too loud. you may get the idea.

The local law officer got sick and tied of the complaints, and put a building code inspection on them, long story short they now need bring their sheds up to class 10a compliance

Anyway back to the system, I have been sending emails back and forth to the mate in regards to the RPM, rated output KW, locked current ratings, AMP loads, type of electrical motor to drive as there is different types of motors in the Australian market place that conform to the 240\415 50hz ratings not the 120/230 60hz ratings as the USA. as he is over seas at the moment and has enough on his plate I have to wait, one point of information that keeps coming up is the design of these systems and the work space/shed, a few web sites go on to state that all gaps in the work space have to be sealed/closed for any dust extraction to work, I don't work in a lab.

With the limited understanding at the moment, because I am still reading different posts and product information of this type of setup. And with the belief that this forum has and continues to help all woodworkers and metalworkers in fact of protecting their health in regards to dust, and when I first joined the various threads on it.

What would be fantastic if it hasn't been done all ready and with the directions for somebody like me to gather the correct information like were to get right size impellers from for different size systems and duct runs, motor sizes in KW, minimum duct size for a small shop, or is it worth putting in place a roof mounted air scrubber that is Australian Based.

that's all for now, as it has taken 3 hours to type this and Im about to chuck a PC out a window

[BobL]

. . . .What would be fantastic if it hasn't been done all ready and with the directions for somebody like me to gather the correct information like were to get right size impellers from for different size systems and duct runs, motor sizes in KW, minimum duct size for a small shop, or is it worth putting in place a roof mounted air scrubber that is Australian Based.

Unfortunately there is no single source for all this.
Manufacturers data for airflow on commercial DCs is done using an industry standard which is physically incorrect and does not match real air flows by as much as a factor of two, and a lot of general and commercial advice about impellers. cyclones and dust collection in general is out of date.

The most comprehensive site for wood dust is Bill Pentz website on wood dust extraction. The next best is probably this forum.

While that site deals with US power systems the fundamental quantity of air flow (CFM) needed is the same whether its done using 110V/220/230/240/389/415V, 12/13/14/15 inch impellers and 50 or 60Hz motors. Technically speaking the fan curve (CFM as a function of back pressure) is the KPI, but if you stick to real CFMs then that will get you quite far.

Bill Pentz Criteria (which I agree with) is that you need about 1000 CFM to be mostly successful at grabbing the dust at the source of the dust generation before it escapes into the shed. Once it escapes it takes hours to clean up a shed and by them most of it has settled and cannot be removed by using regular dust extraction.

The other criteria is that at least 4000 feet per minute is needed in ducting so that sawdust does not fall out of suspension and clog the ducting.

[Opelblues2]

Bobl would this be close or near the flow rates I need for my system

Amount : 3600 cubicmeters per hour (m3/h of flow rate)
Equals : 2 118.88 cubic feet per minute (cu ft/min / flow rate)
Fraction : 2 118 ²²/25 cubic feet per minute (cu ft/min /flow rate)

if so would this unit be suitable.

Ebm-papst Backward & Forward Curve Radials

· Single & Three Phase · 180mm > 630mm · 2 Pole, 4 Pole, 6 Pole Speeds

Flow direction Voltage Frequency Air volume Speed Power input Current

R3G280AU06B1 - CW - 230 50 3600 2800 715 3.1


http://www.actrol.com.au//Global/Ass...-Catalogue.pdf

Had a chat with them today. there web address is

http://shop.edingtonagencies.com.au/contact

[BobL]

None of the fans on that document are suitable for sawdust as they are mostly axial and squirrel cage, i.e. low resistance fans.
To really comment on the backwards curved radials we'd need to see a fan RPM versus pressure curve but my experience with these types of fans is that they are also low resistance and only generate about half the pressure needed for woodworking.
Those quoted CFMs will all be measured according to an industry standard which is physically incorrect - yes the Australian standard is incorrect and the CFM will bear little resemblance to reality in a wood working situation.
What this means is that the claimed 2118 CFM will drop dramatically once any resistance (i.e. narrow ducting, junctions, filters, and machines) is applied but more importantly their design still means that the are also likely to clog with shavings etc.

What is needed is a standard impeller that is relativley open and can shed itself of shavings and curly stuff otherwise the fan will constantly need to be opened up to be unblocked.

[pjt]

28mm is all my blower fan generated.





Pete

[Opelblues2]

I reply

None of the fans on that document are suitable for sawdust as they are mostly axial and squirrel cage, i.e. low resistance fans.
To really comment on the backwards curved radials we'd need to see a fan RPM versus pressure curve but my experience with these types of fans is that they are also low resistance and only generate about half the pressure needed for woodworking.
Those quoted CFMs will all be measured according to an industry standard which is physically incorrect - yes the Australian standard is incorrect and the CFM will bear little resemblance to reality in a wood working situation.
What this means is that the claimed 2118 CFM will drop dramatically once any resistance (i.e. narrow ducting, junctions, filters, and machines) is applied but more importantly their design still means that the are also likely to clog with shavings etc.

What is needed is a standard impeller that is relativley open and can shed itself of shavings and curly stuff otherwise the fan will constantly need to be opened up to be unblocked.

I believe that you have failed to read the beginning of the thread, I do not have a dustbag, I have a cyclone built to the scaled size of the highly rated Bill Pentz system, I do believe on the information that I have look over, sent to me, and very many posts that you have posted that I'm am close to the required air volume needed for my system. and with the information from a gas dynamics engineer, yes that is what Mark is, one of the comments he made when he rang was

"with the difference being that "gas dynamics" applies to the study of the motion of all gases, not limited to air. and because the air that i will be moving has suspended media in it of different weight, size, to list few variants. he has also asked if when I send details of the system that I do them in cubic meters per second or hour, not CFM

There is no narrow ducting its all 150mm I/D pipe, the junctions layouts are not off the shelf stormwater junctions, they have been made to the inflow angles that I was supplied with, smoothed and polished.

the pipe openings to the hoods are all 150mm, as are the gates. The pick up points for the drill press station wraps around three sides to get the most surface area as possible without getting in the way of the job, it also has down draft built into it.

The home built router table has ben fitted with 4 pickup points, one in the router cabinet itself, one fitted behind the fence that can be opened up to 100mm buy moving the face of the fence, a extra one comes over the top above the router when needed this is 200mm long and 50mm deep, and two 150mm ether side of the bench insert. and it is 150mm main feed line with 100mm secondary lines

The fan is on the clean air side of the cyclone, so there is no contact with the chips, sawdust Is a different matter as a percentage of the airflow will have dust in it until the filter deal with that and they are before the fan. this filter is a oil impregnated multi-core tht is used in auto paint spray units

over the last couple of weeks I have reread I think 85 present of the posts in relation to dust extraction and collection on this forum, and over the last six months lots other threads/posts on other forums, and as you have stated on a couple of times the flow rate need to be 28.31 m3/m to archive the removal of the fine dust from the air space around the tool as designed by Bill Pentz.

now the last point what is a standard impeller, is it the straight blade one that makes a hell of a noise when operating at 3600 RPM, as I had a short day today i went around three of the shops here in Mackay that had dust units in stock, two had backward curved impeller and the other was forward curved impeller, now the clearvue impeller is forward curved and it looks like it's over $500 just for the impeller then you will need at least 4KW motor no price in that yet

are you able to direct me to a company in Australia that supplies and services a electric motor that runs at 3600rpm on 240/50hz.

yes I'm having a go at you for one reason, the fan that i put up was recommend by the company I spoke to yesterday, and I pointed out to the person i spoke to the Australian Consumer laws, IE "not for intended use" I do respect the knowledge that you have and I don't know a great deal in regards to fine dust removal for woodworking, but I would find it more beneficial if directions were given to the equipment or suppliers instead off saying that wont work.

[BobL]

I reply



I believe that you have failed to read the beginning of the thread, I do not have a dustbag, I have a cyclone built to the scaled size of the highly rated Bill Pentz system, I do believe on the information that I have look over, sent to me, and very many posts that you have posted that I'm am close to the required air volume needed for my system. and with the information from a gas dynamics engineer, yes that is what Mark is, one of the comments he made when he rang was

"with the difference being that "gas dynamics" applies to the study of the motion of all gases, not limited to air. and because the air that i will be moving has suspended media in it of different weight, size, to list few variants. he has also asked if when I send details of the system that I do them in cubic meters per second or hour, not CFM

There is no narrow ducting its all 150mm I/D pipe, the junctions layouts are not off the shelf stormwater junctions, they have been made to the inflow angles that I was supplied with, smoothed and polished.

The pipe openings to the hoods are all 150mm, as are the gates.

150 mm ducting still has significant resistance, as does any junction no matter how smooth or gentle it is. To eliminate ducting as a source of resistance you would need to go to around 12"" ducting (typical axial and squirrel cage fan ducting) BUT There is a reason for not doing this with wood dust and that is that the air speed will be so slow that the saw dust in the air flow will fall out of suspension. This is explained in detail on the BP site.

tThe pick up points for the drill press station wraps around three sides to get the most surface area as possible without getting in the way of the job, it also has down draft built into it.

A naked open duct and all hoods have resistance - there is no escaping this.

The home built router table has ben fitted with 4 pickup points, one in the router cabinet itself, one fitted behind the fence that can be opened up to 100mm buy moving the face of the fence, a extra one comes over the top above the router when needed this is 200mm long and 50mm deep, and two 150mm ether side of the bench insert. and it is 150mm main feed line with 100mm secondary lines

The fan is on the clean air side of the cyclone, so there is no contact with the chips, sawdust Is a different matter as a percentage of the airflow will have dust in it until the filter deal with that and they are before the fan. this filter is a oil impregnated multi-core tht is used in auto paint spray units as.

It only takes a moment of inattention for the collection bin to overfill and for sawdust to then enter the fan - then it will be a stop and clean the fan operation.
BTW a cyclone also has some resistance (some have more than filters) no matter where it is located in the flow path.

over the last couple of weeks I have reread I think 85 present of the posts in relation to dust extraction and collection on this forum, and over the last six months lots other threads/posts on other forums, and as you have stated on a couple of times the flow rate need to be 28.31 m3/m to archive the removal of the fine dust from the air space around the tool as designed by Bill Pentz.

Perhaps you have not read BP closely enough. It's not just air flow, the fan also has to supply sufficient air pressure when it is under resistance so it all comes down to the fan curve.
Finally all machines and machine ports have resistance (probably "out-resistances" everything else). So no matter what is done, machines can't always be changed all that much meaning that a fan that generates 10-12" of water column pressure is needed. You could ask the manufacturer for a fan curve but like all manufacturer supplied air flow measurements they may not be that accurate.

now the last point what is a standard impeller, is it the straight blade one that makes a hell of a noise when operating at 3600 RPM, as I had a short day today i went around three of the shops here in Mackay that had dust units in stock, two had backward curved impeller and the other was forward curved impeller, now the clearvue impeller is forward curved and it looks like it's over $500 just for the impeller then you will need at least 4KW motor no price in that yet

That's correct, Lots of people have tried to reinvent the wheel on this but there appears to be no cheap way out.

are you able to direct me to a company in Australia that supplies and services a electric motor that runs at 3600rpm on 240/50hz.

3600 rpm motors are a typical US spec resulting from the use of 60Hz power. 50Hz power motors typically run at ~3000 rpm. To get 3600 RPM with 50Hz requires either the use of pulleys or using a 3phase motor with a VFD. These units will spin a motor faster but the impeller will draw significantly more power and in a wood dust removal situation this can burn out the motor. This is explained in great detail on BP website and explains why a 4-5HP is need to move even 1500 (real - not manufacturers) CFM

yes I'm having a go at you for one reason, the fan that i put up was recommend by the company I spoke to yesterday, and I pointed out to the person i spoke to the Australian Consumer laws, IE "not for intended use" I do respect the knowledge that you have and I don't know a great deal in regards to fine dust removal for woodworking, but I would find it more beneficial if directions were given to the equipment or suppliers instead off saying that wont work.

Well I wish I could send you to suppliers of impellers for handling woodworking dust but unfortunately there are none that I know of otherwise I would have done so. Even BP had to ask Jet to make his first serious impellers before he found a factory that custom made impeller blades for his setup.

About the cheapest option I have seen folks on this website do is to use the impeller from a used DC.

[Opelblues2]

No wonder it took you so long to reply to this thread, andits all NO, NO, NO it wont work, please if I go on it will become a slangingmatch I can’t be bothered, as for this thread can the admin close it

[mannum3]

No wonder it took you so long to reply to this thread, andits all NO, NO, NO it wont work, please if I go on it will become a slangingmatch I can’t be bothered, as for this thread can the admin close it

Please keep it going, I have been reading the dust threads for over 12 months and have learnt a lot.

I would like to trail a system I have "dreamed up": the reasoned debate has clarified a lot of my ideas regarding air flow (speed / capacity).

I am sure there are many others who would echo my sentiments.

Cheers Barry

[Opelblues2]

I revived a Email from a past member of this Forum a coupleof hours ago, included in the email was a contact number, I was asked to ringin regards to this thread and It was put to me that the duct work was close tothe very basic system but not perfect, I was given a list in relation to mywork area and that small changes could be made to improve the over all flow, mywords not his.

With the system that I had put together will be very letdown by power unit that I have in place at the moment (blower, impeller, motor,housing) as I was aware of this from the beginning. but I was going in theright direction, I was good to here that I was going in the right direction forI was at the stage were I thought “stuff it” because I felt that the effortthat I was putting in to improve the air/dust control for my hobby was a wasteof time due to Australia standards and equipment was not only incorrect but wasfalse and misleading.

Being told and seeing that on other threads from othermembers that what they were trying to putting together wont work if you don’t obtainthe flow rates, back pressure, correct duct size, filters, and hoods and thelist goes on and on, I started to believe that I will never obtain the dustextraction unit with the constraints of location, funding, and experience.

With some discussion with the person, my direction as a hobbyistwoodworker, it was asked of me not to continue with the direction that thisthread has been going, as there are many variants to take in to account for thesafe removal of fine dust, and until the industry leaders, engineers, manufactures,as well the government started to work together to produce the correct standardsright down to the level of the hobbyist woodworker, don’t forget that this areais a multi million industry in Australia.

In the email I was also sent grafts that have been posted inrelation to some of the dust extraction sub forum, to me it means didly squat, it’sthe same when I pump out septic tanks and have to explain to the home ownerthat they have killed the tank, by poring of the shelf toilet cleaners down thedrain “they kill 99% of the germs and bacteria, you are killing the things thatmake the system work” this is why council’s now injects bacteria in to the pumplines before the waste recovery plants.

I was like when I was still welding / fabricating there weredifferent types of rods, wire, gas, and equipment for different types ofwelding each had a purpose and most had been tested to the Australia standards,some did get through that were banned in other countries because of the fumesthey produced, but the industry to my knowledge got on the problem and removedthese items, for they realised that there could be very expensive litigation. Thismay happen in the world of woodworking if the standards don’t improve.

Below are some of the charts that I have been sent.

Friction loss in standard air ducts are indicated in the diagram below.

• 1 m/s = 196.85 ft/min
• 1 m³/s = 3600 m3/h = 1000 dm³(liter)/s = 35.32 ft³/s = 2118.9 ft³/min = 13200 Imp.gal (UK)/min = 15852 gal (US)/min
• 1 mm H₂O = 9.81 Pa = 9.807x10^-6 N/mm² = 0.0987 10^-3 bar = 1 kp/m² = 0.09678 10^-3 atm = 1.422 10^-3 psi (lb_f/in²)

Example - Air Duct and Friction Loss

The friction loss in a 500 mm main duct in comfort system with air flow 1 m³/s can be estimated as indicated below to 0.05 mm H₂O/m (~ 0.5 Pa/m).

The air velocity in the duct is 5 m/s.

[mannum3]

Great to see this kept going.

I want to build a system to clear the "dust" from my shed.

I need 200mm piping or build ducting from MDF, to the machines. OK

I need a motor and impeller to power the system, WHERE do I get that??

Cheers Barry

[Opelblues2]

Hi Barry.

That is MY main concept problem that I'm finding, based on the information that Bobl has posted in different threads and in relation to the information an I believe testing from the USA based Bill Pentz. There seems to be very conflicting information in relation to motors and impeller combinations for the use in the dust extraction system in our own market place, to add to this problem I have been informed that the Australian standards in this industry are wrong as well.

now what I seem to believe is that Clearvue supply a impeller of two different sizes in Australia, then you will need to buy a electric motor to match or better kW to have the performance that is required operate a dust extraction system. then buy or make the housing to match.

Then on the other side, from industry suppliers that I can use Backward curved radial fans for this type of application, and thus is were I have a problem "who do I believe" one thing I do believe at the end of day is the Australian Consumer laws "fit for intended application"

so as I go down the path of information I have to filter out here say "", and get the facts. I should/will end up with a system that out performs the current of the shelf systems.

I will keep this thread live, for need a outcome that is complete from start to finish