anybody ever make a dual inlet baffel design.

[alan m]

hi there

i am designing my new shop dc system. i want to put it in a corner with a run going along both walls away from the corner.
the troube is joining one line so that there is no very tight bends . the other line will be inline with the inlet to the seperater
i would go with a side inlet design as i feel it is more efficient
has anyone built (or even dreamed ) of such a design.
does the solid part of the slot have to under the first section of the dust coming in.

obvioslyboth inlets would both be going the same direction  (clockwise  etc)

thanks alan

[retired2]

hi there

i am designing my new shop dc system. i want to put it in a corner with a run going along both walls away from the corner.
the troube is joining one line so that there is no very tight bends . the other line will be inline with the inlet to the seperater
i would go with a side inlet design as i feel it is more efficient
has anyone built (or even dreamed ) of such a design.
does the solid part of the slot have to under the first section of the dust coming in.

obvioslyboth inlets would both be going the same direction  (clockwise  etc)

thanks alan

Alan, I know it is an overwhelming task, but I suggest you take a lot of time and start reading back through all the posts on this forum.  That is the best way to get answers to your questions, and probably some things you didn't think about.  Many of your questions and ideas have been discussed or tried before, but you may not get an answer by just posting a question here because many members stop following the forum after a time or simply tire of answering the same questions.

The search function helps a little, but I suggest treating the forum just like a book on building a DC system.  Simply take the time to read it cover to cover.  There is a lot more information here than just how to go about building a separator.

Good luck

[alan m]

i did look throught all the pages. i didnt read every thread as some were of no interest to what i was trying to do.

i never saw any reference to a dual inlet design

i wil read a bit more thow

[retired2]

i did look throught all the pages. i didnt read every thread as some were of no interest to what i was trying to do.

i never saw any reference to a dual inlet design

i wil read a bit more thow

I know there was at least an inquiry and some short discussion about dual inlets, but I don't think anyone had ever built one because the consensus was it would not work.  If you have a shop where you think you need two mains coming to the separator, you would probably be better off joining the two mains with a wye external to the separator.  If you have a one man shop, like most of us hobbyists you will only be running one tool at a time and there is no real advantage to connecting two mains directly to the separator.

[alan m]

i am not sure why it wouldnt work.
you wouldnt have a solid part under the second inlet but i think (i might be wrong) that the solid part is to stop a swirling air moving down ito the seperated dust  adn picking it up again, i dont think it is to stop that initial part of the inlet air going down.

the way it is working in my shop . i would have to a 45,rising length of pipe,90,45, then into the other duct  and into the seperater.
a dual inlet would be easier and have less pipe on one of the runs.

[retired2]

i am not sure why it wouldnt work.
you wouldnt have a solid part under the second inlet but i think (i might be wrong) that the solid part is to stop a swirling air moving down ito the seperated dust  adn picking it up again, i dont think it is to stop that initial part of the inlet air going down.

the way it is working in my shop . i would have to a 45,rising length of pipe,90,45, then into the other duct  and into the seperater.
a dual inlet would be easier and have less pipe on one of the runs.

Maybe Phil will comment on this idea.  I think he did a lot of drop slot testing when he first develope the separator concept. 

I think there are several issues.  First, how are the inlets configures or located?  Sounds like the layout of your shop is driving your thinking here, but are you thinking the inlets will be tangential and spaced some number of degrees apart?  Or, will they be in the same location stacked vertically?

Secondly, with the inlet design you are thinking about, how does the baffle need to be modified to provide the best separation?

And third, a second inlet port might introduce a lot of undesirable turbulance that disrupts the spinning centrifigal dust laden air.  Even one entry must converge incoming air with air already spinning in the chamber.  My build incorporated a minor modification to minimize this problem, but a second inlet port is a whole different matter. 

Unfortunately, many of the questions that appear on this forum do not have answers that can be derived mathmatically.  The can only come from building a test unit.    That involves a lot or time, work, and material.  So, it often becomes a judgement call and personal opinion, and here's mine on dual inlets.  You may build something that does indeed work, but it will be a compromised solution at best.  As I mentioned in another post a separator imposes a pretty heavy loss in SP, and I've poste anemometer readings that quantify that for my 5" build.  I am confident that a dual inlet separator would have higher losses than a single inlet.

[alan m]

i wouldnt see the point of haveing the 2 inlets avove each other as you may as well have one bigger one in that case, i would be aiming for maybe 140-160 degrees  maybe.
im not sure yet.
i can see the second  (and first ) inlets causing turbulence. the un used inlet will create  either a pocket of swirling air (like a pick up  the way it allows the air to pass over the pocket of air) or create a pressure diferental zone that will disturb the swirling air.
either situation i am worried about build up of dust that will all come into the seperater at once when the blast gate is opened.

unfortunitly it isnt the layout of the tools but the shape of the workshop builing. if i put the seperater on the end of the line (one line going around the whole shop) i will have 3 90 degree turnes (done with 45degree fittings) and a few obsticals to bend around.

if i go with a single inlet and 2 lines i will have to have a tight u shape .


i have a different design but i think it would be too complicated. build a blast gate ito the side of the wall of the seperater so that the inside is flush all the way round. this would be very complicated ,expensive, wouldnt work great in my shop.


if i can get some kind of a solid plan with all these small details nailed down i might make it and see.  if it doesnt work i can always block the second inlet and put a skin around the whole inside of the seperator .

[retired2]

if i go with a single inlet and 2 lines i will have to have a tight u shape .

Well, for sure a tight "U" shape is not a good solution.  Without actually seeing your situation, I can't really offer any recommendations.  But here is another photo of part of my shop.  You can see that I have two mains installed and a third is in the works.  The first leg is fully visible and picks up the jointer and thickness planer.  The second main comes into the first just to the left of the clock on the wall.  The main is totally hidden by the soffet in the photo, but you can see the lateral where it joins the first.  The third main will be added as soon as I get time.  The third is the capped lateral that points vertically on the left side of the photo near the DC.  A long radius ell will connect to that lateral and then the line will extend along the ceiling and wall at the left.

I'm sure you situation is different from this photos, but maybe it will trigger some ideas for you to solve you problem without a dual inlet separator.

Regards,
retired2

[alan m]

i will take a picture tommorow.
i am planing to run the dc line aroung at maybe 3 feet 6" (roughly) off of the ground. there is an electrical  trunking and sockets all around the shop at 4 feet (roughly) and cabinetry above the trunking.
by keeping it at that height i will save fittings and make the runs shorter and the line will go straight into the seperater without having vertical sections.
this means the blast gate will be on the y fitting (assuming i can get some) .

the reult is that there is no room to ease the u turn  as it drops .
i could put one run higher but i would have to rebuild all the cabinetry  and buy a lot more pipe.

[retired2]

i will take a picture tommorow.
i am planing to run the dc line aroung at maybe 3 feet 6" (roughly) off of the ground. there is an electrical  trunking and sockets all around the shop at 4 feet (roughly) and cabinetry above the trunking.
by keeping it at that height i will save fittings and make the runs shorter and the line will go straight into the seperater without having vertical sections.
this means the blast gate will be on the y fitting (assuming i can get some) .

the reult is that there is no room to ease the u turn  as it drops .
i could put one run higher but i would have to rebuild all the cabinetry  and buy a lot more pipe.

I can envision the problem now.  With the mains at nearly the same height as the separator inlet, you really don't have many options. 

[alan m]

[alan m]

sorry cant get the pic right.
in the pic above you can see how tight it  is . those sewer pipes are there to represent where the 6" dc pipes will be

[alan m]

[alan m]

the pic above is the design i am think of. there is two sections to this. the first is a round cylender the size of the barrel about 6" (size of inlet duct) . the second section will sit ontop of the first section.
the two inlets will sweep around in the second section and enter the edge of the first section behind the other inlet on the second section.
the top of the first (lower )section will act as a shelf (blues in pic) for the dust to slow down on as it would on the bafel in a normal design .
as it swirls around from the top section into the lower section the dust will fall throught the slot (pink) .
the green is the wall to the seperator.
there will be a baffle with two sections with no slot  just as the dust comes off ot the shelf 

does this look  any way like it could work

thanks alan

[retired2]

the pic above is the design i am think of. there is two sections to this. the first is a round cylender the size of the barrel about 6" (size of inlet duct) . the second section will sit ontop of the first section.
the two inlets will sweep around in the second section and enter the edge of the first section behind the other inlet on the second section.
the top of the first (lower )section will act as a shelf (blues in pic) for the dust to slow down on as it would on the bafel in a normal design .
as it swirls around from the top section into the lower section the dust will fall throught the slot (pink) .
the green is the wall to the seperator.
there will be a baffle with two sections with no slot  just as the dust comes off ot the shelf 

does this look  any way like it could work

thanks alan

I'm not sure if I understand your drawing, but if the green is the chamber wall, then it looks,like your drop slot is set in from the outer wall by about the size of your inlet port.  If that is the case, I don't think it will work.  Look at some of the videos, mine is a good example, that show the action of the dust laden air inside the chamber.  The separation depends heavily on the centrifugal force that pushes the dirt to the outside wall.  If your drop slot is not against the outside wall, you will not likely get any separation.