Location of slot in Thein Topper

[Fabian Valinskas]

Hey guys,  I am making a thein topper for my Delta 50-760 and will have a side inlet, with a center outlet directly up to the DC inlet.  My question is where is the slot location supposed to be? 

When refering to JP Thiens original plans (http://www.jpthien.com/cy.htm), I see that his inlet elbow comes down, and then the slot doesn't start for some distance, and basically the slot then ends before the elbow is coming in.  My plan was to end the slot right before the inlet, and then start the slot 240 degrees before that point.   

I have seen many different versions of the topper, with many different locations for the slot.  Some start it right where the inlet comes into the circular portion..... Some farther in.....   Does anyone know where it should start?

[alan m]

i built mine with the end of the slot just before the inlet and went back 240 degrees .

thats my understanding of where it should be. that way you have a solid portion before the dust gets to the slot
this is to limit the air going straight down into the barrel underneth

[Fabian Valinskas]

That seemed to be my understanding as well.  Makes perfect sense to me.

[alan m]

thats great
report back how its going for you
we all love to see a new build

[RonS]

My top hat is also made for the Delta 50-760. It sits directly underneath the input port of the factory provided stand. Here is a PDF file of the part dimensions showing the location of the slot. A picture of the completed unit is attached.

[Fabian Valinskas]

Thanks for the replies guys.  Mine is going to be similiar to yours Ron, in many ways... Once I get it finished I will post some pics here.

[BernardNaish]

Thanks for the useful picture and PDF plan. It looks as if your rectangular inlet pipe extends right down to the baffle plate and I wonder how far is the end of the outlet pipe from the baffle? Very tidy build did you use bendy MDF for the side wall?

Have you tried having a longer section of rectangular duct between the transition and the top hat? Perhaps 12" to 24" long.  It should ensure that the flow in is less turbulent. I would like to know if this reduced turbulence improved separation or otherwise. Perhaps it works well enough for you not to need to do any more experiments but I am hoping you are as inquisitive as I am.   Regards from Wessex.

[alan m]

from what iv read on the subject., longer transitions are better.
my transition for my 8" seperater is about 18 " +