Dust Seperator - DO or DONT?

[Turaj]

i like the clear cover idea, that was neat. now does that mean the seperator doesnt need to be circular?

That's right. This seperator is square!! The original plan is from ShopNotes #55. They had designed it to go on a trash can (still square top) and I changed it for my box. In this design, air hits a baffle board, drops the large chips and take the smaller particles to DC.

also i see three pipes, 2 4" and one 2", what is the third pipe for? and can you explain the two top comparments (one big and the other small)?

My set up is based on what I already had and perhaps not the most efficient. I used the seperator to also create a "Y" for the piping! The 2" goes to TS, DP and BS and the 4" goes to my Jointer and planer (they are close to each other). The other 4" (in the back) goes to the DC. I had made this top for my previous DC which only had 4" in-take. If I was to build a new one, I would make that 5" to go with 5" in-take of the DC. I would also bring a full 4" to all the tools and reduce it (to 2") right at the tool but still keep the blast gates ("Y").

i see the latches on one side of the lid, how do you empty it, isnt it a little too heavy (the weight of the wood cabinet alone) to lift and dump?

There are latches on both sides and they are to keep the lid air tight to the base. Two sides of the base are hardboard (re-inforced) to keep it light and the whole thing is on castors. So it is not that heavy. I find the top (lid) heavier than the base!!!

I have more pictures and the original ShopNotes plan. Let me know if you need them!

[SARGE..g-47]

Morning FP...

I am certainly not an aerodynamic engineer, but before Turaj posted I would have told you that I would think it would need to be circular as I have never seen a cyclone or tornado that didn't have circular action. When you straighten one out they call it a hurricane or typhoon depending on what neck of the woods you hail from. ha.. ha... ha..ha..ha..

But.... with Turaj testifying that he is "gettin' er done" with square (and I would think the baffle would be the key there) I have some holes shot in my theory. And it's just that.. a theory as I cannot nor have I done testing to even slightly conclude that circular is the ticket and would be more efficient?

Now... if Turaj would be so kind as to add a circular set-up and get back to us on what differences if made.. we would be sitting on top of some decent info. (Just kiddin' Turaj as I wouldn't go to the trouble either.. if it's working don't fix it!

So... in conclussion, form your own opinion and pick your poison.

Regards...

[SARGE..g-47]

Morning Newood 2..

Pretty nice set-up and I am surprised to hear that you are efficient out to 25' from all I've read recently. Just goes to show that hear-say of "the printed work" is not always as reliable as what has acutally been dicovered "in the trench" by those that have gotten dirty to find the real truth.

Regards...

[SARGE..g-47]

Morning Jeff...

"Sorry! Do you have a thread on the RT that contains photos, etc? Seems like a pretty cool set up"... Jeff
***********************

Well.. no as far as I can remember and perhaps that isn't far. But.. with the help of my young, lovely assistant Lisa and one of those marvelous "digital picture taker thingies" ( I am a hold-out on modern gadgetry and cell phones but the digital camera is a god-send), I created info and pictures in about 10 minutes over-all.

The RT base is 3/4" scrap birch ply and birch doors set on Euro hinges. Sits on a HTC 2000 mobile base. The top is double 3/4" MDF glued and then laminated with what we used to call formica (but the actual stuff they use now is some type of counter laminate and I can't keep up with it is currently called.. ha.. ha...). Phonelic insert from Highland Woodworking held in by gravity supporting a Milwaukee 3 1/2 HP router (a Clydedale router IMO) with built-on above the table adjustment even though it is very simple to surface it and do it sitting on top of the table as you will see latter in a picture. Slots cut in table top for fence to slide fore and aft.

Fence is made of laminated 3/4" birch ply glued and screwed, then coated with un-cut poly. Adjustment slots added for opening and closing center cut slot to zero clearance the bit. T-handles lock all adjustments down. The cavity for dust in the fence was cut with hand held back saw and then chiseled out with a mortice chisel. That shape transformed into a cicular walled cavity with a spoke-shave.

Base of cabinet is two fold. Top sealed off to house the router and a 2 1/2" dust port in left rear corner facing the cabinet. Bottom is storage and sealed from the top router shelf at the front where it meets the door with campers RV tape as I used to seal any leaks on my Uni-saw for dust collection purposes.

The tops edges were sealed with 3 coats of poly and then I added a wood strip over them and enamel painted. The bottom of the top is sealed with 4 coats of un-cut poly to keep out moisture and that it has done as the top and fence haven't moved since 5 years ago when I constructed it!

That's it... simple design.. simple construction... simple operator behind the wheel. Cost not including router was about $50 which includes phonelic insert plate and out-side connection switch.

Again simple.. but with all the features I saw on high $$ designs that I wanted rolled into one little simple package without "getting my shorts in a wad" over which one to buy as I like this on that one and this on the other one. And when do they go on sale? In other words choose what you want instead of somebody else choosing for you and in the words of a truly great American (Larry the cable-man)... "Get er done"....

Regards...

[footprintsinconc]

Thanks

thank you very much eveyone! your opinions, suggestions and comments are really helpful. this is what i love about the people on this site and this is why this is truely a unique place to be a part of.

sarge, love the RT setup. if you didnt open the cabinets doors, looks like a powermatic setup! i would definately agree with you thoughts, "choose what you want instead of somebody else choosing for you..".

regards,

[Turaj]

... think it would need to be circular as I have never seen a cyclone or tornado that didn't have circular action. ...
... I have some holes shot in my theory. And it's just that.. a theory as I cannot nor have I done testing to even slightly conclude that circular is the ticket and would be more efficient?

Sarge, I don't see any holes in your theory! I also believe that a circular motion is required to create a cyclone effect and that would be more efficient! In fact a shop built cyclone is on the long term plan (and I mean looooong)

The current set up for the separator (no tornado effects) works for me as I start with about 1200 CFM (Delta 50-760) and very short distance to each tool so the drop in CFM (however significant) still gives me plenty at the tools

Now... if Turaj would be so kind as to add a circular set-up and get back to us on what differences if made.. we would be sitting on top of some decent info. (Just kiddin' Turaj as I wouldn't go to the trouble either.. if it's working don't fix it!

First thing first, I have to find my shop under all kinds of junk in the middle of expanding it. But there is hope

[LCHIEN]

circular vs square separator

There are several ways to build a separator

One of the really good ways is a cyclone which is to some extent a weight separator. The inlet is aimed to use the incoming velocity to whirl the contents around the perimeter of a funnel shaped cyclone. As the whirl goes down and the diameter decreases, the heavier particles are pulled to the outside by the centrifugal force and the lighter, smaller particles are in the innner part. The exiting air must go up the middle to the exit tube, it eventually catches the smaller particles and takes them out while the larger heavier particles slide down the outside and fall out the cyclone hole in the bottom. True cylcones are designed accroding to strict mathematical rules relating the height, diameter, slope of the funnel sides and the air velocity and flow rates and inlets, exit and bottom openings that govern the cut rates and particle sizes for specific fluides of gasses.

In a rectangular separator, the principle of operation to go from a high velocity, small cross-section area to a lower veolcity, larger cross section area, then back to a high velocity, small area. All the while the flow rate is the same, in CFM. Frequently the slow air flow is directed over or around a baffle to slow it some more. Larger heavier particles will be suspended in a high velocity stream but fall out of a low velocity stream. This type of separator has the baffle and low velocity section over a catch bin to catch the falling particles in a dead air zone where they'll stay once removed from the stream. In this type of separator, the incoming hose is 4" dia. and is routed through a box that might be 12" wide and 8" high and 20 inches long and maybe sent around a baffle. The exit hoes goes back to 4". No cyclone needs to be created. This actually works quite well. If you know the CFM you can divide it by the cross section area to get the velocity. Some references exist that relate velocity to the ability to carry certain particle sizes, its a simple matter to design one that has a large area long enough for the particle to fall down. These are shown in many shop DIY books and someone here last fall posted a large plastic box under his BT3100 to catch dust fromhoses from all his tools going I think to his shop vac. P.S. I was the term "Drop Box" used for one of these... fits well.

The so called trash can separator has elements of both. It generally swirls the air around the perimeter of the can, It sucks the exit air from the top center of the swirl. However it does not have the strict funnel shape.
the heavier, bigger stuff goes to the walls of the can and the lighter stuff exits. Part of the precipitation of cuttings is from the cyclone effect and partly simply due to the slowing air flow at the outer wall near the bottom of the can.

I don't profess to be a cyclone/fluid/air flow expert but I have worked with mechanical engineers engaged in separating solids from fluid and air streams using centrifuges and cyclones.

[footprintsinconc]

your explanations are always refreshing. always thought out. this one in particular helped remind me of some of my fluid mechanics material from school . - thanks for the explanation.

[vaking]

Hello Omar,
I posted some info on my separator earlier at a link below:
http://www.bt3central.com/showthread...dust+separator
This is different from the theory that Loring provided. It is simply intake to the separator (2 inputs 2-1/2" size, one with gate) and output from the separator (4" pipe to DC) and a mesh filter in between. Mesh is mounted on an angle and everything that does not fit through the mesh drops down in a bin. All devices in my shop use 2-1/2" connections and this separator is also my way of making a Y- connection from one larger hose to 2 smaller. I still use the DC with only one tool at a time but table saw and router table are connected at 2 points each.

[SARGE..g-47]

Evening All...

Thanks Turaj.. Loring and Vaking for some thoughts that go inside the box. At this point my personal set-up is finally in place and probably will be for a very long time. But... I learned a few things that could be passed to some of the locals looking for alternatives to a cyclone.

BTW Turaj, an idea on finding your shop down underneath the clutter would be to try what I do at the end of a shop day. Even with a cyclone.. DC.. and a Jet air filtration system over-head the final thing I do is open the two large sliding doors. Put up all the hand tools and Then.... (drum-roll).....

Start in the rear of shop outward with a 100 mph electric dust blower and create a "blow-out sale"! If it isn't heavy machinery, heavy stock or hasn't been put in a proper place.. then I don't need it that bad and out it goes to the street to be either picked through by those people that ride around early in the morning that pick through things or be picked up by the "trash authorities to be" and hauled off.

The shop is now ready for traffic the next business day!

Good luck in the search for your shop "Missing in Action". Got to be down there somewhere and if you dig deep enough, you're bound to hit the "Motha-Lode"...

Regards...

[Turaj]

Start in the rear of shop outward with a 100 mph electric dust blower and create a "blow-out sale"! If it isn't heavy machinery, heavy stock or hasn't been put in a proper place.. then I don't need it that bad and out it goes to the street to be either picked through by those people that ride around early in the morning that pick through things or be picked up by the "trash authorities to be" and hauled off.

Great idea with one small problem My shop is in the basement Some days I really wish I could do that

[footprintsinconc]

thanks for the post Alex. interesting setup. one question though: is that mesh fine vinyl mesh?

regards,