Thought you might wanna see these
Reg
New Planer Dust Hood
Moderator: nektai
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mystry_tour
- Posts: 357
- Joined: Mon Mar 13, 2006 9:33 pm
- Location: Greenville Tenn
New Planer Dust Hood
Here you go pete
Thought you might wanna see these
Reg
Thought you might wanna see these
Reg
I fought to keep the Gov. in power......they keep screwing around I'll fight to get rid of them.
Dust collection duct work...
The duct work looks very nice and I suspect that the duct will work well for transporting the chips away from the instrument. I'll be interested to hear how it works.
Given the nice cross-section of practical machine junkies and artists on this forum, I'd like to make a few suggestions using this project as an example that we can talk about.
When I look at this duct I see a few things, I see:
1. A turning section (just short of 90 degrees)
2. A contraction section with a ratio of 5 to 1 (This is a guess based on estimated dimensions of the duct which appears to contract from and area of 6"x24" to pi*3"^2)
3. A turning section (as the angled walls of the contraction, or nozzle, meet the vertical walls to the circular duct)
The suggestions that I would make for a section of duct like this are the following:
1. Increase the interior radius of the turning section and smooth the transition between the turning and the contraction sections. This would allow the boundary layer of the flow within the duct to remain attached to the wall for a little longer, reduce the size of the recirculation region in the contraction section which may improve performance. Please note that this may also reduce the load on your dust collection fan (reduced pressure drop) and the aero-acoustic noise (noise produced as a result of velocity gradient in the flow).
2. If space is at a premium (as it often is) there are a few things that may be done to reduce boundary layer separation. One of the simplest ways to reduce the size of a recirculation bubble, is to add a small series of air inlets just beyond the corner (the size and shape of the inlets - probably a series of very fine holes - would require some experimentation) of the inside curve. This would allow the duct to inject some clean air which would run up along the inside wall of the duct and break up the recirculation bubble a bit.
3. Although it would drastically increase the complexity of the construction, a contraction section that smoothly transitions from rectangular to round and vertical in one plane to vertical in a second plane would also improve efficiency and probably the dust collection performance. I used to have a little piece of code that would compute just such a transition. I'll need to see if I can dig it up and convert it to something for you guys to try out (that may take a while!).
Without having spent much time in a semi-commercial wood shop, I'm unsure how much of the noise that you experience and that the energy that you pay for is tied to the dust collection systems. If any of you are interested in ways to potentially reduce noise and improve dust collection system efficiency I'd be willing to offer a hand.
- Jeff
Given the nice cross-section of practical machine junkies and artists on this forum, I'd like to make a few suggestions using this project as an example that we can talk about.
When I look at this duct I see a few things, I see:
1. A turning section (just short of 90 degrees)
2. A contraction section with a ratio of 5 to 1 (This is a guess based on estimated dimensions of the duct which appears to contract from and area of 6"x24" to pi*3"^2)
3. A turning section (as the angled walls of the contraction, or nozzle, meet the vertical walls to the circular duct)
The suggestions that I would make for a section of duct like this are the following:
1. Increase the interior radius of the turning section and smooth the transition between the turning and the contraction sections. This would allow the boundary layer of the flow within the duct to remain attached to the wall for a little longer, reduce the size of the recirculation region in the contraction section which may improve performance. Please note that this may also reduce the load on your dust collection fan (reduced pressure drop) and the aero-acoustic noise (noise produced as a result of velocity gradient in the flow).
2. If space is at a premium (as it often is) there are a few things that may be done to reduce boundary layer separation. One of the simplest ways to reduce the size of a recirculation bubble, is to add a small series of air inlets just beyond the corner (the size and shape of the inlets - probably a series of very fine holes - would require some experimentation) of the inside curve. This would allow the duct to inject some clean air which would run up along the inside wall of the duct and break up the recirculation bubble a bit.
3. Although it would drastically increase the complexity of the construction, a contraction section that smoothly transitions from rectangular to round and vertical in one plane to vertical in a second plane would also improve efficiency and probably the dust collection performance. I used to have a little piece of code that would compute just such a transition. I'll need to see if I can dig it up and convert it to something for you guys to try out (that may take a while!).
Without having spent much time in a semi-commercial wood shop, I'm unsure how much of the noise that you experience and that the energy that you pay for is tied to the dust collection systems. If any of you are interested in ways to potentially reduce noise and improve dust collection system efficiency I'd be willing to offer a hand.
- Jeff
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mystry_tour
- Posts: 357
- Joined: Mon Mar 13, 2006 9:33 pm
- Location: Greenville Tenn
Hi Pete. It is mine yes. I did some of the work and some ws done at the fab shop at work, I don't have a roller. No I haven't got it running yes as I haven't got the dust system running. Waiting of th the concrete to dry in the extention to move the machine tools in there and put up the cyclone. It is 3 hp and will be very close to the planer so it should work pretty good.
Hi Jeff.....welcome to the place. I am just a hillbilly and not very educated so it seems your thoughts are very consice and well thought out. I only have one question....huh. I read it a few times and sorry its way over my head.
tour
Hi Jeff.....welcome to the place. I am just a hillbilly and not very educated so it seems your thoughts are very consice and well thought out. I only have one question....huh. I read it a few times and sorry its way over my head.
tour
I fought to keep the Gov. in power......they keep screwing around I'll fight to get rid of them.
Jeff, Did you hear my mind blowing up all the way up there in Vermont?
Your wind tunnel science makes us all look like cavepeople. I would however love a consultation before I ever build a dust collecting hood again. I actually could use some advice for the one I made for my oliver planer. here is the thread http://machinejunkie.com/forum/viewtopic.php?t=99 It doesn't suck as fully as needed. It is my current theory that the having the instant square to round change at the top is a major loss of suction. i am jealous of mystry's beautiful transition in that area. My thought is to roll up some more sheet metal and weld it in to create better fillets. I am open to better suggestions.
I would say the noise issue is not a problem- the sound of the planer and collector seem to be the dominant winners in this category.
Pete
Your wind tunnel science makes us all look like cavepeople. I would however love a consultation before I ever build a dust collecting hood again. I actually could use some advice for the one I made for my oliver planer. here is the thread http://machinejunkie.com/forum/viewtopic.php?t=99 It doesn't suck as fully as needed. It is my current theory that the having the instant square to round change at the top is a major loss of suction. i am jealous of mystry's beautiful transition in that area. My thought is to roll up some more sheet metal and weld it in to create better fillets. I am open to better suggestions.
I would say the noise issue is not a problem- the sound of the planer and collector seem to be the dominant winners in this category.
Pete
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mystry_tour
- Posts: 357
- Joined: Mon Mar 13, 2006 9:33 pm
- Location: Greenville Tenn
Hi Guys,
Well I fired up the dust collection system today with the new hood on the planer. It worked like a charm. At first my heart sank because when I ran an oak 4X4 through it I was watching the hose......damn no chips. I ran it through again.....same thing. Then It dawned on me to OPEN theblast gate
the chips wen whirling through the clear hose and into the barrel.....I was so excited I bout peeded myself.
So Pete the worry about the tight 90 Deg. turn is not a problem It works great
Tour
Well I fired up the dust collection system today with the new hood on the planer. It worked like a charm. At first my heart sank because when I ran an oak 4X4 through it I was watching the hose......damn no chips. I ran it through again.....same thing. Then It dawned on me to OPEN theblast gate
the chips wen whirling through the clear hose and into the barrel.....I was so excited I bout peeded myself.So Pete the worry about the tight 90 Deg. turn is not a problem It works great
Tour
I fought to keep the Gov. in power......they keep screwing around I'll fight to get rid of them.
-
mystry_tour
- Posts: 357
- Joined: Mon Mar 13, 2006 9:33 pm
- Location: Greenville Tenn
Hey guys, just got here.
I know this is an old post, but if someone perusing this forum comes across this, I'd like to add a reference I came across in my surfing.
http://search.sheetmetalworld.com/tutorials.cfm
This is a great website that has easy explanations on how to measere and cut sheet metal forms including; transitioning from square to round and making a cone with a pitch (which I used).
Anyway hope it helps.
Stephen
[/url]
I know this is an old post, but if someone perusing this forum comes across this, I'd like to add a reference I came across in my surfing.
http://search.sheetmetalworld.com/tutorials.cfm
This is a great website that has easy explanations on how to measere and cut sheet metal forms including; transitioning from square to round and making a cone with a pitch (which I used).
Anyway hope it helps.
Stephen
[/url]