TopHat vs. Cyclone Separator Lid

[jgt1942]

For the past few weeks I've been researching Cyclone Dust Collectors and was focused on the Bill Pentz model to use with my Grizzly G1029Z2 2 HP Dust Collector, while trying to create my SketchUp model of everything I encountered the Thien TopHat and Cyclone Separator Lid and because it is MUCH simpler I've decided to change but I do have a few questions.

• Why not use the TopHat for the big DC and the smaller shop vac, e.g. possibly a smaller version for the shop vac? For my big DC I will be using 6" pipe and for the smaller shop vac I thinking of using 4" with reducing adapters to work with all of my small hoses.
• Are any of the measurements in the TopHat that are critical or any ratios I need to keep in mind? The only thing I've seen is possibly the cutout in the baffle and this seems to have a range that is acceptable.
• When creating a ShetchUp of my pland when possible I use an existing SketchUp model (tools, or whatever I need) and found a great TopHat model by Tom Porterfield and after viewing a posting by rawdawgs50 on YouTube I'll modify the inlet in Tom's model to duplicate what rawdawgs50 did.
• Is the distance between the top and baffle critical, for one of my units I'll use 6" pipe and the other I'll use 4" pipe.
• For those with a big DC with the TopHat, how often do you change the filter?
• Any thoughts on sound reduction?

[retired2]

The transition piece of in this sketch is poorly designed.  As a minimum, the area of the rectangular end should equal the area of the round end, and better yet, the area of the rectangular end should be 10% greater than the round end.  The design as shown creates a entry restriciton and simply adds to the losses created by the separator.

The second small rectangular metal piece shown in the sketch is an unneccessary detail, unless you simply want to line wood surfaces with metal.  This assumes the wood inlet dimensions match the dimensions of the rectangular end of the transition piece.  It may be a little more clear by looking at the construction photos of my build.

[Dougp28704]

The area of the round is 18.85 sq inches. The area of the rectangle is 19.5 sq inches.

[retired2]

The area of the round is 18.85 sq inches. The area of the rectangle is 19.5 sq inches.

18.85" is the circumference of a 6" circle, not the area.  The formula for the area of a circle is pi x radius squared, so the area of a 6" circle is 28.26 sq. in., not 18.85 sq. in.. 

[Dougp28704]

Doah! Sorry. I forgot my jr. high math.

[jgt1942]

The transition piece of in this sketch is poorly designed.  As a minimum, the area of the rectangular end should equal the area of the round end, and better yet, the area of the rectangular end should be 10% greater than the round end.  The design as shown creates a entry restriciton and simply adds to the losses created by the separator.

The second small rectangular metal piece shown in the sketch is an unneccessary detail, unless you simply want to line wood surfaces with metal.  This assumes the wood inlet dimensions match the dimensions of the rectangular end of the transition piece.  It may be a little more clear by looking at the construction photos of my build.

I agree that the transition is not good and this is one of the things I'll modify.

What is the URL of your post with the construction photos. I looked but could not find it.....

[jgt1942]

retired2 - by chance do you have a SketchUp model of your unit?

[Peter]

First, I will take full blame for the error in the posted sketch: I am Thom Porterfield. My middle name is Peter. :)

Second, that sketch came from my original design that used 6"? duct and was otherwise full of flaws. When I resized my system to 5"?, I neglected to change the note on the inlet duct. In my current design the transition goes from 5"? to a 7.25" x 3" rectangle. I believe retired2's complaint is covered by this change. My apologies to the group.

[Dougp28704]

Jgt1942,

The thread you are looking for is:
http://www.jpthien.com/smf/index.php?topic=563.0

The thread Topic is:
5", Rectangular Inlet, Bellmouth Outlet with Air Straightener, Top Hat Separator

I can't ever find what I am looking for using the site search. I started adding url's to my browsers favorite list. I have know idea how people search and find what they are looking for.

[retired2]

First, I will take full blame for the error in the posted sketch: I am Thom Porterfield. My middle name is Peter. :)

Second, that sketch came from my original design that used 6"? duct and was otherwise full of flaws. When I resized my system to 5"?, I neglected to change the note on the inlet duct. In my current design the transition goes from 5"? to a 7.25" x 3" rectangle. I believe retired2's complaint is covered by this change. My apologies to the group.

Peter, I would never have confessed to all of that.  You are going to heaven for sure!

[Peter]

I confessed, retired2, because I couldn't let you go around telling the world what a lousy designer I am.  ;)

Regarding the inlet design rawdawgs50 shows in his videos: It is lots easier to build, I suppose, but there are all sorts of cavities around that round pipe to cause unwanted turbulence.  If you look at interior pics of the top hat designs that use round inlets, and even some of the original in-can designs, you'll see random piles of dust in these cavities.  My original top hat, which I made for my Shop Vac, uses a round pipe. Even with the higher static pressure and faster air flow afforded by the Shop Vac, there is a build-up of dust inside that clearly shows the results of eddies.

Okay, it's not really a big deal, especially with the Shop Vac, since the build-up of dust doesn't seem to hamper its function. But I suspect that with the larger volume and slower velocity of air pulled through the separator by the dust collector blower, it could be an issue. That's why I take to heart the advice that forcing the dust-laden air against the outer circumference of the separator and to eliminate as much as possible any untoward turbulence, will bring the performance of an otherwise marginal machine (such as the HF "2 hp" unit) to acceptable levels.

[jgt1942]

Peter, thanks for the update. Why did you change from 6" to 5"?

[jgt1942]

First, I will take full blame for the error in the posted sketch: I am Thom Porterfield. My middle name is Peter. :)

Second, that sketch came from my original design that used 6"? duct and was otherwise full of flaws. When I resized my system to 5"?, I neglected to change the note on the inlet duct. In my current design the transition goes from 5"? to a 7.25" x 3" rectangle. I believe retired2's complaint is covered by this change. My apologies to the group.

Peter, much thanks for the update. In another post I think I saw one from you stating that you were going to build another TopHat with 6" ports. Did you do this, do you have the SketchUp model?

[Peter]

jgt:
I changed from 6"? to 5"? because the dust collector I will use, the so-called 2 HP unit from Harbor Freight, just can't move enough air to be effective in 6"? ducts.  And there is too much friction loss in 4"? ducts.

My SketchUp model is essentially the one you found earlier, but I have edited the model for 5" duct as I explained.  I did not keep the model for 6"? duct. Sorry. Doug28704 has a pretty decent model too. And of course, so does retired2. Both of these gentlemen have the air flow in the separator moving counter clockwise (when viewed from above) to match that of the blower fan. My unit, because of space considerations, will rotate clockwise. I will install some sort of "air straightener" similar retired2's solution, as it seems the optimum air flow into the impeller is to not rotate at all.

Now if you are interested, I have fabricated two long-sweep elbows using 6"? S&D that I will not use now that I'm going with 5"? metal duct. One is 90?, the other is 45?.  Radius to diameter is 1:3.  :D

[jgt1942]

Peter, yes please post the SketchUp.

I've started to recreate my SketchUp for my Thien TopHat which of course is a combination of drawings I've found and ideas within this forum. A YouTube posting by PitBull has also been super helpful.

Peter, one of the things you did in your drawing has me stumped and would like to know how you did it. When I double-click on a component everything disappears except that component. Then when I click anywhere other than on that component everything reappears. NEAT!

My Grizzly G1029Z2 2 HP Dust Collector has a 6" input but the output of the 12 3/4" impeller is reduced to 5". Per Grizzly this was done to increase the speed of the air but I did see another DC on their site that was very similar with a 6" output pipe.

I'm in the early stage of shop setup and decided make the DC the first priority. I've attached a SketchUp image and the SketchUp model. Ops, the SketchUp file exceeds the size allowed by the forum.

On the Grizzly site I saw a stand for a setup that would be easy to recreate with the TopHat and the DC I currently have, image has been included. This would solve several issue for me

• Allow me to easily route the pipe near my 10' ceiling to feed all of my wood tools.
• Use the same amount of floor space currently used by my current unit.
• Simplify the overall design