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
Quote from: alan m on June 30, 2012, 09:18:57 AM
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
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
Quote from: alan m on June 30, 2012, 11:47:54 AM
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.
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.
Quote from: alan m on June 30, 2012, 12:14:56 PM
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.
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 .
Quote from: alan m on June 30, 2012, 02:47:59 PM
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
(https://www.dropbox.com/s/yiwzray05h4i9dw/Testsetup-02.jpg?raw=1)
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.
Quote from: alan m on June 30, 2012, 05:47:25 PM
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.
(//)
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
(//)
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
Quote from: alan m on July 01, 2012, 10:40:21 AM
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.
sorry .
it is hard to show what i mean.
the bottom 6 inchs (of a 12" high seperater) is a cylender . the wall of the cylender follows the slot around . the inside edge of the blue part is the inside edge of that lower section.
the blue parts then get wider out over the lower section. there will be a step or shelf that i hope will act like the section in the baffel with no slot.
if i can come up with an easy way of doing it i might slope that shelf for the last few (6-8") inchs to allow th eair to lower down into the lower section and avoid the second inlet.
Quote from: alan m on July 01, 2012, 01:46:59 PM
sorry .
it is hard to show what i mean.
the bottom 6 inchs (of a 12" high seperater) is a cylender . the wall of the cylender follows the slot around . the inside edge of the blue part is the inside edge of that lower section.
the blue parts then get wider out over the lower section. there will be a step or shelf that i hope will act like the section in the baffel with no slot.
if i can come up with an easy way of doing it i might slope that shelf for the last few (6-8") inchs to allow th eair to lower down into the lower section and avoid the second inlet.
I hope it works because that is going to be a complicated fabrication.
when i lay it out full scale on the material i will try and make the green parts the same on both sides and use a router tempate to make them all the same.
the bottom 6 " section (just round donut shapes will still be able to be used for the normal design if this doesnt work . all i would have to do is make another top section with one inlet.
i wish phil would comment (and a few more) to add a few ideas or catch an obvious mistake etc.
i am not sure if it will work or not but i will give it a go anyway.
any ideas on how to make it better.
Quote from: alan m link=topic=729.msg4183#msg4183 date=1341182694
any ideas on how to make it better.
/quote]
Yeah, one inlet! :)
Quote from: retired2 on July 01, 2012, 05:55:54 PM
Quote from: alan m link=topic=729.msg4183#msg4183 date=1341182694
any ideas on how to make it better.
/quote]
Yeah, one inlet! :)
very funny.
i wish i could.
.
I think the picture shows drops slots that are too wide, and improperly positioned.
If I were you, I'd figure out a way to go with a single inlet. Multiple inlets are all about compromises.
that picture isnt to scale . the slot would be the normal 1.25 ".
your opinion on where the slot should go is what i want your help on.
i think that the solid part of the slot needs to be where the air and dust would hit the baffel as it comes down off of the shelf and around the lower section. i am hoping that the slot on one side is where the air will hit coming around from the other inlet.
do you think that doing a dual inlet design will result in a slightly less efficient seperation or a total loss of seperation.
if phil or anyone else can find a solution to avoid this i am open to it. i cant work out a way to join one line into the other without a very severe u section of pipe.
hi me again.
i thimk i will try thise.
i am someone that would rather try and see it fail than not try but always wonder. something is only imposable when a solution hasnt been found and if people dont try then the solution will never be found.
i havent read anything that puts me off trying it
as i am venting the last of the fines outside i am not too worried about if the efficiency is 95 or 98 % as long as there are no big bits going out.
i am thinking of putting a second baffel inside the ring of my dc unit to try and seperate out anything that gets past the dual input one.
on the slot detail
i am not sure where that spot (for the solid part of the the slot ) should be when the seperater is double the normal height. let alone where it should be for a dual inlet.
i am thinking of using a 3/4 inch baffel but with no solid part. then rebate the bottom of it by 1-2" (creates a thin edge all around as well) and make a coresponding ring to fill the slot where i want no slot.
this piece would be rebated on the top to fit into the rebate on the baffel . so i should be able to put the piece (or pieces ) where ever i want. i will play with the alignment and shape/size etc untill i am satisfied or fed up ;).
at least i will know i tried.
The baffle right after the inlet should always be snug to the wall of the bin. For twin slots, I'd do 75 (larger, right under the first inlet), 105 (reduced drop slot), 75 (larger again, right under the 2nd inlet) 105 (reduced drop slot). Those are in degrees.
thanks phil . i will start wil that and see how it works
not sure what to do. i want to build this (just to prove it to myself that it might work) but cant afford to redo it straight away . so i am thinking of building 2 normal ones but one going clock wise and the other anti clockwise. i planed on getting a bigger dc power scource but i might use both . one on each .
i was planning on making them the same in every other way so that we can see if the direction makes a difference.
Alan,
Building one separator is a lot of work. I would never build two just to see if there is a difference in performance between one that rotates with the DC fan rotation and one that is opposite.
If there is a difference, it will not show up in the efficiency of the separation, it will show up in how much air the fan is moving, and unless you have an anemometer or some other way of measuring air flow you will not be able to see or hear the difference.
I believe rotation direction only makes a difference if you are close-coupled like my separator, and in that situation, rotation in either direction is a problem (see the information I posted several times from Cincinnati Fan). If you are planning to have a very short length of pipe from the separator outlet to the fan inlet, then just build the separator to best suit your duct configuration and use an air straightener for maximum fan performance.
i wouldnt build 2 unless it was the only way.
i need 2 because i cant efficiently put the 2 branchs into 1 inlet without a tight u turn. i think i would use the opertunity of having to buold 2 to test the diffewrence.
i am planig on getting a anemometer to see whats going on
Quote from: alan m on July 11, 2012, 01:42:13 AM
i wouldnt build 2 unless it was the only way.
i need 2 because i cant efficiently put the 2 branchs into 1 inlet without a tight u turn. i think i would use the opertunity of having to buold 2 to test the diffewrence.
i am planig on getting a anemometer to see whats going on
I forgot your "U" turn problem, but if two separators solve the problem it is worth the trouble. Try to avoid a hard turn at the entrance to the fan.
i am planing on mounding the dc housing up over one baffel and using a short piece of flex hose (almost none) . something like what you have done. . i am not sure about the second seperater and its dc unit (not bought yet). i might tamperaerally raise the 1st dc unit up and flex pipe across to the second seperater . the second one wont be as efficient but at least i can use it untill i can afford to buy another dc unit.
i will make the two the same so that i can conect both to the 1 dc (not at the same time) and cmpare rotational direction.