Metal Dust Collection ?

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04-02-2020, 1:43 PM
Doug Walls

Metal Dust Collection ?

I recently picked up a small Aget model 420 dust collector that was designed for metal dust collection, It was originally used on a surface grinder.
https://i.postimg.cc/xTPfHG4B/IMG-5847.jpg

The upper filter area had quite a bit of fine dust in it when I picked it up & the lower collection box was about 1/3 full!
The excess dust in the upper filter section could have been from not having that much space for collection (just the lower section) https://i.postimg.cc/VvKfCnfj/IMG-5842.jpg

Seeing that the filter & the collection areas were fairly small, I decided to disassemble the unit so I could make a standard style dust collector.
https://i.postimg.cc/MK0T5JvP/IMG-6021.jpg https://i.postimg.cc/dVq0SNCq/IMG-6022.jpg https://i.postimg.cc/MpPz36xD/IMG-6122.jpg

I noticed a internal baffle after I had the main cyclone section removed!

"Not that easy of a task since the unit was pretty much spot-welded together, But the trusty die-grinder & saws-all took care of that"
:D

I'm thinking of removing the original baffle, Or trying to make a internal air-ramp to help eliminate the air turbulence probably caused by the original baffle?
https://i.postimg.cc/G3y9Byr1/IMG-6031.jpg https://i.postimg.cc/Z5MhFwFs/IMG-6134.jpg

There was also a internal deflector that fit inside the exhaust tube!
In the original design it deflected the exhaust from directly blowing on one point of the filter, But in my modified version I'm thinking of leaving it out?
https://i.postimg.cc/VsqmQBm5/IMG-6035.jpg https://i.postimg.cc/GtxCFrqv/IMG-6036.jpg https://i.postimg.cc/ZKzn65Kv/IMG-6040.jpg

My plans are to use a 20gal. metal garbage can for the collection container & a cartridge style filter for the exhaust.

Eventually the dust collector will be used with a 10" Van Dorn pedestal grinder & a 6" Ex-Cell-O carbide grinder I also recently picked up.

https://i.postimg.cc/SN06sVkh/IMG-5967.jpg https://i.postimg.cc/vBLPzjQ5/IMG-5951.jpg

Any ideas or comments on my modified metal dust collection system?

Doug
04-02-2020, 2:34 PM
Bruce Page

Pretty cool. The carbide grinder should have diamond face wheels and an oil dripper. They don’t generally create “dust”. At least that’s how the ones that I have used were set up.
Those are both great grinders.
04-02-2020, 3:11 PM
Doug Walls

Quote:

Originally Posted by Bruce Page

The carbide grinder should have diamond face wheels and an oil dripper. They don’t generally create “dust”.

Yeah the one wheel is a USA made diamond wheel that lists for $240 new!
Made the purchase even more of a deal, Considering I only paid $88 ($75 + Auction Fee) for the grinder!

I don't really plan to use the grinder for carbide tooling, I basically picked it up because of the price!
Figure I'll use it mainly for sharpening hand tools & drill bits, So the diamond wheel & coolant drip will probably not be used.
It did come with two regular grinding wheels.
https://i.postimg.cc/TPCXSNRX/IMG-6109.jpg https://i.postimg.cc/qRFHBthb/IMG-6110.jpg

Quote:

Originally Posted by Bruce Page

Those are both great grinders.

Thanks !

Doug
04-09-2020, 2:01 PM
Doug Walls

3 Attachment(s)

Quote:

Originally Posted by Doug Walls

Any ideas or comments on my modified metal dust collection system?

Well it doesn't look like I'm going to get any comments or ideas on modifying this dust collector!
Probably not too many home shops with dust collection for metal dust?

My progress so-far:
I remove the inner baffle & the 6" dia. inner exhaust outlet duct.
https://i.postimg.cc/wT9WWqzW/IMG-6137.jpg https://i.postimg.cc/tgnD17dg/IMG-6142.jpg

I also added a longer cone section that will give me a 4" discharge outlet instead of the 6-1/2" with the original set-up.
https://i.postimg.cc/TYkcCnCw/IMG-6162.jpg

I'm still trying to figure out some type of chip deflector for the inlet side of the unit?
Being this style of cyclone is a push through design, I want to prevent a small part or large chip being able to make direct contact with the impeller!
Attachment 429875 Attachment 429876 Attachment 429877

Doug
04-09-2020, 3:23 PM
David L Morse

Quote:

Originally Posted by Doug Walls

Well it doesn't look like I'm going to get any comments or ideas on modifying this dust collector!

If you'll take questions instead I'll ask what are you trying to accomplish with the modifications and why did you remove the vortex finder and neutral vane?
04-09-2020, 7:24 PM
Doug Walls

Quote:

Originally Posted by David L Morse

If you'll take questions instead I'll ask what are you trying to accomplish with the modifications

Based on the amount of fine dust in the upper filter area of the original dust collector when I first got it from a local shop that closed-up, The dust collector didn't seem to be working that great.

I'm hoping that the modifications will help improve the collector's efficiently by containing more of the dust in the storage bin.

Quote:

Originally Posted by David L Morse

why did you remove the neutral vane?

As mentioned before"

Quote:

Originally Posted by Doug Walls

I'm thinking of removing the original baffle, Or trying to make a internal air-ramp to help eliminate the air turbulence probably caused by the original baffle?

The way it was originally set-up, I figured that the dust/air hitting that "Flat-Wall" would create
turbulence & not allow the dust to swirl correctly inside the cyclone.

I do plan on making a air-ramp like shown in this old post
https://sawmillcreek.org/showthread.php?199339-Pentz-Cyclone-Air-Ramp-Question

Quote:

Originally Posted by David L Morse

why did you remove the vortex finder

If your referring to what I called a "internal deflector"

https://i.postimg.cc/VsqmQBm5/IMG-6035.jpg

I figured that was primary used to deflect the exhaust towards the sides of the original set-up.
It's also designed to fit inside a 6" ID. outlet duct!

From what I've read on the Bill Pentz web-site http://billpentz.com/woodworking/cyclone/index.cfm the idea size outlet size for a smaller 12" Dia. cyclone should be around 4"

Doug
04-10-2020, 11:38 AM
Doug Walls

Quote:

Originally Posted by David L Morse

why did you remove the vortex finder

Well it looks as though I have learned a new cyclone terminology!
I Googled "Vortex Finder" and it showed what I called the outlet/exhaust duct.
https://i.postimg.cc/1RCyqKq3/Sketch...-separator.png
In all of my reading on the Bill Pentz web site, I don't remember the term "Vortex Finder"

Anyways back to your original question on why I removed the vortex finder, Or what I called the exhaust duct!

Based on the information I've read the idea size for my 12" Dia. cyclone is around 4" (or about 1/3rd. the size of the cyclone's dia.)

I'm planning to replace the vortex finder with a 4"dia duct and I'll also be adding the internal air ramp.
Another modification I'll be doing is making a removal "top/cover plate" which will make installing the new vortex finder & air ramp easier & allow access to the inside if a blockage should accrue.

Doug
04-10-2020, 12:34 PM
David L Morse

1 Attachment(s)

There's more to cyclone design than BP. You might find this interesting:

Attachment 429943
04-10-2020, 5:20 PM
Doug Walls

Quote:

Originally Posted by David L Morse

There's more to cyclone design than BP.

Yeah that's for sure!
I'm use to referring to Bills web site since most home hobbyists are familiar with it.

Here's a article I found pretty interesting http://blog.fluid-eng.com/2013/09/un...st-collectors/
If you look at the original dust collector I picked-up & notice the small collection area I out-lined, Then consider these quotes from the article above!

Quote:

However, the amount of space that the cyclone discharges into is important. In a high-performance cyclone, a very intense vortex exists at the dust discharge point. If dust is allowed to accumulate in this area it will re-entrain and discharge through the gas outlet.

Quote:

Using airtight dust receivers sized to provide a dead air space with a diameter at least twice, and a height three to four times, the diameter of the dust discharge prevents these problems.

So based on the above quotes & the original dust collectors 6" discharge area, The dust collectors collection container should have been at-least 18" deep!

Doug
04-10-2020, 5:45 PM
David L Morse

Quote:

Originally Posted by Doug Walls

Yeah that's for sure!
I'm use to referring to Bills web site since most home hobbyists are familiar with it.

Here's a article I found pretty interesting http://blog.fluid-eng.com/2013/09/un...st-collectors/
If you look at the original dust collector I picked-up & notice the small collection area I out-lined, Then consider these quotes from the article above!

Quote:

However, the amount of space that the cyclone discharges into is important. In a high-performance cyclone, a very intense vortex exists at the dust discharge point. If dust is allowed to accumulate in this area it will re-entrain and discharge through the gas outlet.

Quote:

Using airtight dust receivers sized to provide a dead air space with a diameter at least twice, and a height three to four times, the diameter of the dust discharge prevents these problems.

So based on the above quotes & the original dust collectors 6" discharge area, The dust collectors collection container should have been at-least 18" deep!

Doug

Yes! Some cyclones include a vortex breaker at the outlet to address this problem. This is a real issue on the "short cone" cyclones because of the large diameter discharge. Laguna has added a simple vortex breaker to their cyclones.

This is also an issue with the separator rings on baggers (so called single stage DCs). A Thien baffle is essentially a vortex breaker and when added to the collector ring on a bagger reduces the re-entrainment problem.
04-10-2020, 8:52 PM
Doug Walls

Quote:

Originally Posted by David L Morse

This is also an issue with the separator rings on baggers (so called single stage DCs). A Thien baffle is essentially a vortex breaker and when added to the collector ring
on a bagger reduces the re-entrainment problem.

Jets solution to this issue was called a vortex cone, From what I've read it basically works like a Thien Baffle!
http://i.ebayimg.com/images/i/262876...-1/s-l1000.jpg

Here's an interesting video on a guy that had a DIY version of the vortex cone & up-graded to a cyclone system.
https://www.youtube.com/watch?v=e7kpogfLjRw

Doug
04-10-2020, 9:24 PM
Doug Walls

Quote:

Originally Posted by David L Morse

Yes! Some cyclones include a vortex breaker at the outlet to address this problem. This is a real issue on the "short cone" cyclones because of the large diameter discharge.

I'm wondering if that's what that "X" shaped center deflector piece was also suppose to do?
It would probably work as a air straightener, Which would in-turn break the vortex!

Another odd thing about the cone on this collector besides it originally being short with a large discharge, It's at about a 20 degree angle?
Compared to a typical woodworking cyclone which is usually longer & more like a 12 degree angle.

I know there's a lot of differences between wood dust & metal/grinding-wheel dust, So I'm guessing that the sharper angle may have something to due with the metal dust's weight & density?

Doug
04-11-2020, 7:45 AM
David L Morse

Quote:

Originally Posted by Doug Walls

Jets solution to this issue was called a vortex cone, From what I've read it basically works like a Thien Baffle!
------
Here's an interesting video on a guy that had a DIY version of the vortex cone & up-graded to a cyclone system.
-----

Doug

Yes, the vortex cone serves the same purpose as a homemade baffle.

The system in that video is far from optimum. There's no need for two centrifugal separators. They both add resistance. The SDD is the equivalent of about 30' of 5" pipe. The original separator ring is close to 50' of 5" pipe. The baffle, if he left it in, adds to that.

Quote:

Originally Posted by Doug Walls

I'm wondering if that's what that "X" shaped center deflector piece was also suppose to do?
It would probably work as a air straightener, Which would in-turn break the vortex!

Another odd thing about the cone on this collector besides it originally being short with a large discharge, It's at about a 20 degree angle?
Compared to a typical woodworking cyclone which is usually longer & more like a 12 degree angle.

I know there's a lot of differences between wood dust & metal/grinding-wheel dust, So I'm guessing that the sharper angle may have something to due with the metal dust's weight & density?

Doug

I wondered about that straightener too. It just seems to be in the wrong place. Of course with the shallow collection bin there's hardly room for it below the exit.

It's possible that both the cone angle and bin height were constrained by some overall height requirement for the system. A shorter cone will also have less pressure drop.

The big difference in the two dusts is density. Because of it's higher density metal dust is easier to separate. Of course it also requires higher air velocity to move it.
04-11-2020, 9:22 PM
Doug Walls

Quote:

Originally Posted by David L Morse

The system in that video is far from optimum. There's no need for two centrifugal separators.

That's what I thought also!

Quote:

Originally Posted by David L Morse

I wondered about that straightener too. It just seems to be in the wrong place.

I imagine that the straightening section helped a little bit with the
re-entrainment issue, But I believe the main purpose was to deflect the exhaust toward the sides of the upper filter area.

Quote:

Originally Posted by David L Morse

It's possible that both the cone angle and bin height were constrained by some overall height requirement for the system.

Yeah that's a possibility!
It's fairly small & compact compared to a full-size system, Maybe it was considered a portable or moveable unit?

Doug
04-29-2023, 3:01 PM
Doug Walls

4 Attachment(s)

I'm bringing this old post of mine back up to update it due to recent questions about the AGET dust collectors.

The metal dust collection was put on hold since I sold the carbide grinder shown above.
After adding the longer cone section shown in post# (4) I reinforced the modified cone assembly with fiberglass strips covered with an epoxy/graphite coating to seal it all up, but it's basically been sitting up on a shelf for a few years.
Attachment 500416 Attachment 500417 Attachment 500430 Attachment 500431

I've learned a lot lately & I picked up a hand-held anemometer to measure the CFM & airspeed while trying to get my main dust collector up & running. https://sawmillcreek.org/showthread....32#post3250632 Once I finish that project, I'll probably start back working on the modified AGET dust collector & see what kind of CFM readings I get from it.

Doug