Another Thien Build

[BernardNaish]

I have been using a drop can with a shop vacuum cleaner with 2 ½" plastic piping for several years with considerable success. Made from a large trash can this had a round almost tangential inlet pipe set into its side towards its top.  I fixed a plastic bucket to the lid set upside down and fixed the outlet pipe in the middle. This was to preventing debris from being sucked straight out of the can.

The shop vac was replaced by a 1.5 hp dust collector a month back and the ducting increased to 4" and considerably extended. The can scrubbed out badly which it had not done previously. To overcome this problem I have made a Thien baffle from 5/16" MDF with a 240 degree 1 1/8"wide drop slot.

To avoid having anything that would create turbulence above the baffle I have fitted two steel brackets on the underside rather than spacer pillars between the bottom of the lid and the baffle. Two of these brackets fit into slots in blocks screwed to the can wall. Another block locates and supports the 120 degree un-slotted section of the baffle. The brackets are 3"long to give good clearance under the drop slot and 1 ½" away from the slot edge.

To get the inlet air stream as free of turbulent as I can I have changed the inlet pipe for one with a rectangular section.  I made the transition by hammering the round pipe down onto a 1 1/8" wooden block till I had a rectangle 1 1/8" wide and I found this quite easy to do. I have set this into the can making sure its top edge is as close to the top as I could get it and it is about 1/8" down.

I have left the bucket in place but cut it down to the same height as the outlet tube.
I have set the baffle so that its upper surface is half the height of the inlet rectangle below the bottom of the inlet. The end of the outlet pipe is set down by half the height of the inlet pipe. By this means I have divided the space between the top and the baffle into thirds.

I have a lot more work to do to improve other parts of this system and it is early days yet but so far it looks promising. Little debris is now getting into the DCs' collecting bag and the drop can has noticeably more fine dust in it than before. It is frustrating not being able to see what is going on inside and I am looking forward to making a top hat with polycarbonate walls.

I will post a sketch and some photographs soon. Feedback gratefully accepted.

[tvman44]

I just completed my 2nd Thein style separator and built it a little different than the 1st one and it works even better.  I took the 1st off my DC system in the shop and connected it to a smaller 1Hp DC strictly on my Scroll Saw temporarily and plan to replace it with a 3rd separator identical to my 2nd separator which is connected to my DC system for the rest of the shop. :)

[BernardNaish]

Here are some pictures. TEST UPLOAD