Redo on my Collector

[Jtull01]

Hi All,
Thanks for all of your input. I'm going to trash (pun) the trash can lid collector/baffle I originally made, and which fails missrably.
I am using a Harbor Freight 2HP unit with a secondary plastic bag and Wynn filter.

In that light, I am planning a flat bid and top hat design that does not extend into my 30 gal metal trash can. About 28" diameter.
I am planing a roughly 12.5" high collector. it will again have 5" lead in and out metal ducting. I found a diagonal 6.25 X 6.25 inlet to put by the slot. It will direct the intakes dust against the smooth sides of the collector.

Anyone want to make a sketch for me to follow????

Do you think 2" between the bottom of inlet and the baffle is enough clearence?
How deep(long) should I make the secondary pick up? In other words clearance from the top of the baffle?
Your advice is most valued and appreciated.
Jeff

[retired2]

Hi All,
Thanks for all of your input. I'm going to trash (pun) the trash can lid collector/baffle I originally made, and which fails missrably.
I am using a Harbor Freight 2HP unit with a secondary plastic bag and Wynn filter.

In that light, I am planning a flat bid and top hat design that does not extend into my 30 gal metal trash can. About 28" diameter.
I am planing a roughly 12.5" high collector. it will again have 5" lead in and out metal ducting. I found a diagonal 6.25 X 6.25 inlet to put by the slot. It will direct the intakes dust against the smooth sides of the collector.

Anyone want to make a sketch for me to follow????

Do you think 2" between the bottom of inlet and the baffle is enough clearence?
How deep(long) should I make the secondary pick up? In other words clearance from the top of the baffle?
Your advice is most valued and appreciated.
Jeff

I have no first hand experience with double high top hats, but if I were convinced they were significantly better than single high, I would probably build one.  And if I built one, I would put the inlet near the top, not near the  bottom.  Why?  Well, if it is near the bottom what is the point of making it double high in the first place!  And, did you ever see a cyclone with the inlet set low?

[kayak]

Like R2 said, put the inlet as high as possible. 

I have a theory regarding how high above the baffle the outlet should be.  I haven't been able to try it out yet, and others on this board have voiced skepticism about it.  They may be right, it might not work.  But here is my idea.  Divide the area of the outlet (for a 5 inch duct, that would be 19.635 square inches) by the circumference of the duct (again, for a 5 inch duct, this would be 15.708 inches).  For 5 inch duct, this would give a result of 1.25 inches.  My theory is that this would be the minimum clearance between the baffle and the outlet.  More than this would be okay, but less than this make the outlet "starve for air".  However, I don't know yet how much a low clearance like this would contribute to bypass. Bypass in a separator is a bad thing...

Let us know what you go with and how it turns out!  Good luck!

[Jtull01]

Opinion please?
In my planning , as I said, I am going to use a 6.25" X 6.25" square angled intake coming off a 90* elbow from the top.
All the pictures I have seen on the net show a direct path into the slot.
Should I direct the intake to the outside wall of the seperator, or?
Thanks,
Jeff

[retired2]

Opinion please?
In my planning , as I said, I am going to use a 6.25" X 6.25" square angled intake coming off a 90* elbow from the top.
All the pictures I have seen on the net show a direct path into the slot.
Should I direct the intake to the outside wall of the seperator, or?
Thanks,
Jeff

If you are building a top hat separator, the inlet should be tangential to the circumference.  If that is what you mean by "directing the intake to the outside wall", then the answer is yes.

If you must have a 90 degree turn close to the separator, or anywhere for that matter, avoid the cheap 1xD bends.  They cause significant losses in velocity and SP.  Use a minimum of 1.5xD bend.  If you have 1xD elbows that are segmented and adjustable, use two of them set to 45de degrees to get your 90 degree turn.  That way you will have a longer radius bend with much better performance.  Be sure to make all the segments air tight with caulk or duct tape.

[dabullseye]

in the first post you said "flat bid" what do u mean. dont quite understand what u mean by saying your using a 6.25 sq coming off the top. are you making a 2x tophat with side inlet (located at top) or are you trying to make a 2x height of the original thien separator with the 6.25 inside. post a sketch