Exit port extention length/depth?

[RIBuilder]

First off, I would like to thank Phil for his creation of this wonderful mechanism, and for sharing it with all of us on this forum. Also, a thank you to everyone who has contributed to his invention and to this forum. There is such a wealth of great information and knowledge here that has contributed to the evolution of his design for varying applications, setups, and dust collection systems. There is a great video here on You Tube demonstrating the function and efficiency of this design using a see-through top hat design. This is what ultimately helped me to make my decision to build my own instead of buying a Dust Deputy or a similar variation.

I recently build mine based off of his original Shop Vac prototype build and it functions wonderfully. I used the base of a broken 12 gal Ridgid shop vac for my separator. For the rest of the construction I followed his design almost completely. I was going to install a PVC union in the exit port but it works nicely without it and I am unsure if it will help. The only dust that makes it to the Shop Vac is ultra fine and it only accumulates on the filter. Would installing the extension union in the exit port help to reduce this dust? And what depth should it protrude below the lid to maximize collection of fine dust?

I noticed in the video above that his exit union is about 2-3 inches below the lid. Keep in mind I only have 3 1/2 inches to work with, he has about 6 inches. In your opinion will it offer better collection and what is the best depth for my setup? Thanks again.....

[RIBuilder]

Here is a pic of my setup. I am using a 1 7/8" crush proof flexible hose 12' long and it works great for my smaller powertools. I use it with my belt and vibration sander, miter saw, 3 1/2" power planer, and my router. Right now I have a Delta contractor's table saw and I am thinking of either getting a Grizzly Hybrid saw or sealing the base of my existing saw (at an angle maybe) and adding a 2 1/2 port. Do you think my setup will be able to handle either table saw? Or am I looking at having to get a dust collector? The grizzly has a 4" port on the side but I could reduce it to 2 1/2", although I don't know if I will get efficient collection.

Any of you guys using the shop vac setup with a table saw? Any thoughts as to what I should expect? I have a very limited garage shop right now and I am starved for space. I don't work in the shop daily and only do my custom projects in there periodically, all other work I do on site.

[phil (admin)]

Go with an inch.

[RIBuilder]

Thanks for a quick response. I followed your design almost entirely using only the photos and description you posted. In one of the photos (the one from the top) it appears that there is a PVC fitting under the black port but in the other photos it isn't visible. Now that you mentioned it I noticed it does faintly appear in on of the side view photos. Thanks again for the help!

I wish you success in obtaining a patent and exclusive rights for your design. I can only imagine the time and effort that you put in trying to perfect it and you deserve recognition and credit. I salute you sir and truly appreciate your time!

[Bulldog8]

There is a great video here on You Tube demonstrating the function and efficiency of this design using a see-through top hat design.

Phil, the OP links to a video that shows a top inlet separator with a very deep chamber. In another post you talked about how a deep chamber can improve the separation of fines.

If a person were to build a top hat similar to the video, but use a side inlet, do you think that the outlet pipe should extend further down into the chamber? It seems to me that the 1/2 D rule works when the chamber is the height of the inlet, but when the chamber is purposely left deep then the inlet should be high and the outlet lower. Does this make sense?

Steve

[phil (admin)]

It seems to me that the 1/2 D rule works when the chamber is the height of the inlet, but when the chamber is purposely left deep then the inlet should be high and the outlet lower. Does this make sense?

Steve

Yes, as you make a unit taller, the outlet tube should be extended towards the baffle, and the inlet should be held as high as possible.  This will increase the rotations before exiting the outlet.

[RIBuilder]

I saw another video on youtube in which the creator constructed a similar deep transparent top hat design. He placed the inlet tube directly on the top of the unit, at an angle, but without an elbow. It doesn't enter the chamber at all and although it seems to work, it isn't nearly as smooth as the first video I posted above. So in a deep chamber higher is better for the inlet, but no elbow at all seems to be counter productive.

To me it appears that the elbow helps to create the cyclonic motion and it places the dust at the right location for optimum separation. Without an elbow it appears that the dust enters the chamber unevenly, and it's separation seems to work but not nearly as efficient as other designs. As I have learned in construction and design there are always many different ways to accomplish the same thing, but some are always better than others. I like Phil's original design.