Thread: Dust Extraction for new shop

Originally Posted by codycook

Hi Dave,

Thank you for breaking this down. If I'm understanding correctly I could get nearly the same performance from a 14" impeller operating at 64 Hz as a 15" impeller at 60 Hz?
And if the fan is running through a VFD I would be able to control how many Hz the motor is operating on?

Yes, you should be able to compensate some for the size difference, BUT, beware the power demand. You don't want to use more than the motor is rated to deliver. Keep an eye on the current draw.

Originally Posted by codycook

I think I am going to go take a look at the dust collector I mentioned in a previous reply:

Dusk collector - Watering Equipment - Sydney, Australia | Facebook Marketplace

If the impeller is a 14" impeller I think I will buy it with the hope I can run it through a VFD at higher Hz as Dave mentioned and get it to perform more like a 15" diameter impeller. If it is not a 14" impeller do you think this would be a good candidate as a basic used DC?

Even in the US at 60 Hz 5 hp motors are usually paired with 15" fans. If it's only a 14" fan the motor is usually 3 hp. At 50 Hz no one who expects to make a profit would waste a 4 kW motor on 14" fan. Do you have 415 V available?

Originally Posted by Colin62

Do you have similar figures for the noise generated? My gut tells me that the smaller impeller running faster will be noisier, but that’s purely a guess.

No, sorry, I don't.

Originally Posted by dmorse

Yes, you should be able to compensate some for the size difference, BUT, beware the power demand. You don't want to use more than the motor is rated to deliver. Keep an eye on the current draw.



Even in the US at 60 Hz 5 hp motors are usually paired with 15" fans. If it's only a 14" fan the motor is usually 3 hp. At 50 Hz no one who expects to make a profit would waste a 4 kW motor on 14" fan. Do you have 415 V available?

I'm going to try to have a look at that unit and hopefully it is at least a 14" diameter. I do have access to 415v

Originally Posted by codycook

...... I have been working on building the cyclone. I had a go with bending the MDF into a cyclone shape and the MDF did not want to cooperate. The 150mm diameter at the bottom of the cyclone was just too tight of a radius for the MDF.........

It is a long shot but try and wet the MDF a little with a wet rag or spray bottle, hot would likely be better, to see if it becomes more pliable. I think the outside curve but play with a piece of scrap. When done let it dry and sand if needed. If it works you are golden and if not, well you were going to toss it.

Pete

Hey Pete,

Last night I tried wetting the MDF with a spray bottle but didn't have any luck. I have a steam mop that I'm going to try to use tonight. Maybe the added heat will make it bend. :fingerscrossed
If that doesn't work I'll be putting my metalworking hat on

I may have found a 14" Impeller.

Impeller [431006] for Power Tools | eReplacement Parts

Anyone have any thoughts on this one? This is the 14" impeller Bill Pentz used before going to 15". The only thing raising concern for me is that it says it is plastic...

i would prioritize investigating the used unit you referenced. It's impeller is almost certainly larger than 14" and includes the housing and a 4 kW motor for about the same price as the Jet part.

"plastic" is an error in the Jet part description

That impeller looks like riveted metal. Both e...parts and the Jet powermatic site list the part as plastic. I asked them both and will post the reply here if they answer.
Looking at the photos the blade height is tapered and the ends are angled, not square. Maybe curved blades with that profile is common with later model impellers.

I had recently two 2HP, 12" fans sitting in my shop, one with a modern impeller design as the above, the other with straight radial blades with a tiny bit more area, non tapered with square ends and quite small axial clearances. I never got to measure the flow (CFM), I'll get caned for that, but running them side by side and holding my hands over the outlets, the old radial blade one was clearly stronger.

The Jet Powermatic DC-1900 that uses that 14" impeller has an 8" inlet I think and gives it's flow as 1891CFM
https://images.jettools.com/c/8/d/7/...92074k_man.pdf

EDIT. Added more words on old radial blade fan..

There's nothing "old" about a radial design compared to either a backward curve or forward curve. They have different characteristics and the blade angle is chosen to meet the requirements of the application.

Regarding the PM1900, this might be interesting:



It's from the May, 2013 issue of Wood Magazine. Note that the testing was done with a six inch test pipe. Extrapolating from that you could expect about 1700 CFM with eight inch pipe.

Just a head up that those tests would have all been done at 60Hz.

FYI, I believe these are the impeller sizes for some of the machines in that chart:

* Powermatic PM1900 - 14" impeller, single stage - probably radial
* Grizzly G0440 - 14.5" impeller, cyclone with long body like Bill Pentz recommends. Replaced by G0441, which has 15" impeller. When I compared the fan curve of the G0441 to the fan curve the ClearVue (sort of) published, they are very similar.
* Grizzly G0562Z - 12.75" radial impeller, single stage
* Oneida V3000 - cyclone - modern versions of this machine have 15" backward inclined impeller, not sure what it had in 2013

As the charts show, cyclones robs some of the airflow.

Mark

The impeller for the PM1900 is shown in that link that codycook gave earlier and my link to the manual. Blades are curved and swept back. Manual shows blades with constant height and square ends, the ereplacement part looks like tapered height and angled end.

Dunno if this is any help to you but I built a BP inspired cyclone about a year ago.
I put a very short post about it sometime in July last year.
I’d picked up a motor fan unit of a Grays auction and a member here gave me a drum from a Carbatec dusty.
I’ve a couple of mates who do car resto and they let me use their gear to do the cone.
The layout for the cone came from an Internet sheet metal site.
I did dummy it up in cardboard first.
It seems to work pretty well and is exited out thru a hole in an annex wall into an old dog kennel in a dead area of the yard.
The dust and chips fall into a plastic box and the air exiting is clean.
Its very noisy so I’ve put an enclosure around it and built a muffler also lined the walls with foam and form ply.
All up a lot of time but I’m retired.
I run a 30” disc and it handles that ok.
Heres a few pics,I’ll add one of the muffler when I’m next out there.
H.
Pic of muffler added, plus one of enclosure.
The muffler has internal curved ply transitions and fibreglass centre wrapped in wire and more ‘glass held in place by wire on the internal walls.

Originally Posted by clear out

Dunno if this is any help to you but I built a BP inspired cyclone about a year ago.
I put a very short post about it sometime in July last year.
I’d picked up a motor fan unit of a Grays auction and a member here gave me a drum from a Carbatec dusty.
I’ve a couple of mates who do car resto and they let me use their gear to do the cone.
The layout for the cone came from an Internet sheet metal site.
I did dummy it up in cardboard first.
It seems to work pretty well and is exited out thru a hole in an annex wall into an old dog kennel in a dead area of the yard.
The dust and chips fall into a plastic box and the air exiting is clean.
Its very noisy so I’ve put an enclosure around it and built a muffler also lined the walls with foam and form ply.
All up a lot of time but I’m retired.t
I run a 30” disc and it handles that ok.
Heres a few pics,I’ll add one of the muffler when I’m next out there.
H.
Pic of muffler added, plus one of enclosure.
The muffler has internal curved ply transitions and fibreglass centre wrapped in wire and more ‘glass held in place by wire on the internal walls.

We are building an 18" BP cyclone with the 1.64 scaled length cone from 1.0 mm cold rolled steel, in our metalworking shop, at the moment. (it took about a day to get to our current stage, which is just before final assembly) We have a metal working shop with a slip roller, a bead roller & a lathe to turn any profiles we need, so we rolled some strengthening ribs into both the cyclinder & cone. We have a 3HP 3Ph motor & impeller to test it with initially, and I believe we have sourced a 5Hp 3ph motor & impeller (free) for additional testing. We intend to make our own bell shaped restrictor plates in the BobL style to free up airflow. If the testing does not crush the cyclone, I will look around for a bigger 2nd hand motor/impeller to test with. I intend to put a test frame together so we can move it around attaching it to different ducts in our main machine room, and swap various components in, before we install it anywhere in a production sense.

We are now into the planning stages for a 2nd version of the cyclone. The idea is to have a built in flange to bolt the cone to the cylinder rather than weld it, move up to 1.2mm sheet, possibly using iconel, depending on the cost, and improving the upper plate assembly. 1.2mm is as big as our rollers are rated.

Could you tell me what the material you constructed the cyclone from please, and what thickness.
(edit: I just picked up from your July2020post you had used 1mm steel fabrication & a 2HP motor with a 14" impeller) It looks like your implementation went well structurally.

thanks in advance
Brendan