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Thread: Metal Dust Collection ?

  1. #1
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    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.


    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)

    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.


    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"


    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?


    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?



    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.


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

    Doug

  2. #2
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    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.
    Please help support the Creek.

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  3. #3
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    Quote Originally Posted by Bruce Page View Post
    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.



    Quote Originally Posted by Bruce Page View Post
    Those are both great grinders.

    Thanks !

    Doug

  4. #4
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    Quote Originally Posted by Doug Walls View Post
    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.


    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.


    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!
    IMG_6148.JPGIMG_6149.JPGIMG_6153.JPG

    Doug

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    Quote Originally Posted by Doug Walls View Post
    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?
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

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    Quote Originally Posted by David L Morse View Post
    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 View Post
    why did you remove the neutral vane?
    As mentioned before"
    Quote Originally Posted by Doug Walls View Post
    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 View Post
    why did you remove the vortex finder
    If your referring to what I called a "internal deflector"



    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

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    Quote Originally Posted by David L Morse View Post
    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.

    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

  8. #8
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    There's more to cyclone design than BP. You might find this interesting:

    StandardCyclones.jpg
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

  9. #9
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    Quote Originally Posted by David L Morse View Post
    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!
    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.
    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

  10. #10
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    Quote Originally Posted by Doug Walls View Post
    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!
    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.
    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.
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

  11. #11
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    Quote Originally Posted by David L Morse View Post
    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!


    Here's an interesting video on a guy that had a DIY version of the vortex cone & up-graded to a cyclone system.


    Doug

  12. #12
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    Quote Originally Posted by David L Morse View Post
    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

  13. #13
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    Quote Originally Posted by Doug Walls View Post
    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 View Post
    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.
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

  14. #14
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    Quote Originally Posted by David L Morse View Post
    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 View Post
    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 View Post
    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

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