J. Phil Thien's Projects

I have a question that all here might respond to...it is prompted by Todd's description of how he tested the unit. He essentially planed some wood to generate chips and debris.  But there is no way to determine the amount of chips (although it just occurred to me that I guess you could calculate the volume of wood planed off and use that as the theoretical input).

Here is how I conducted my test (which resulted in a 97.2% efficiency. I took the collected material from the bottom bag of my dust collector.  The majority of this stuff was fine particles (I have done no planing in the recent past).  I weighted out a certain amount of ounces of dust, then spread it out on the floor and sucked it up slowly, just like Phil did in his online video.  I then emptied the metal garbage can and weighted what had been collected there.  For completeness, I cleaned out the shopvac including the filter prior to the test, then weighed the filter. After the test I reweighed the filter. Results: Input amount = 60.7 oz, Separator = 59.0 oz, In filter = 1.7 oz, or 97.2% separation. Actually, there was probably some particles adhering to the sides of the ducts, the internal crevices of the vac, etc., but this seems like hair splitting. 

Do you think this was an "unfair" test in that the majority of the input debris was already pretty fine particles. Would the separation efficiency be higher with a more uniform mix of particle size in the input stream?

Ken

David:  I am intregued by your comments but have a hard time visualizing your system from the description.  Is there any way you can post pictures of the details of your design/implementation.

I am very interested in learning more.  I have built Phils design for a 10gal garbage can with a shop vac.  Here is a pic of the cart I made for the collection.  Note the raised platform for the ShopVac so I could keep the inlet hose to the ShopVac as short and straight as possible.

I was able to purchase a used, high vol (700cfm/1.5hp) "barrel-top" dust collector.  The motor sits on the top with the impeller shaft vertical, and the inlet port at the center of the top.  The inlet is at the outer edge and has a built-in 90 turn to the exit within the drum is horizontal.  It is exactly like the upper plate in Phil's design.  It sits on top of a 55 gal drum and is ripe for having a larger baffle plate attached to hang below the plate.  I found a picture (crude and small) of this design and it is attached.   

I sort of gather from other posts that you all think that the baffle design will work with the higher flow rates of these larger blowers.  Is that right?

Thanks,
Ken

You said:  "And for the average woodworker, it's irrelevant whether the baffle efficiency is 97.2% or 98.5%. But, with larger impellers and motors, this could be important."

I am interested in what you base this statement on.  I thought that much less than the 98.5% and higher efficiencies would still lead to filter plugup, especially in high volume generation of small particles such as sanding tables, exhaust capture from orbitals, etc.

I have just put a separator together (using ShopVac and 2 1/2 hose) and did detailed testing and got 97.2%.  Phil has pointed out that I have one design flaw (my center outlet port is flush with the surface of the top plate rather than extending down in a short distance), so maybe I can achieve higher.  Based on your comment, I shouldn't worry, though....which is why I am asking.

Thanks,
Ken

Great, thanks.  I suspected as much.

The new pictures are really very good and reveal a lot more detail.  Good job.

Ken

Thanks much for the new picture.  Very clear and the profile of the elbow is helpful.  The detail is so good I just have to ask: what is the wingnut (and its bolt) doing?  I can see nothing in the side photo on your main web page.

This is a nice solution and I would like to try and make one.  If it works like you say, a PayPal donation is coming.

It is hard for me to understand the design of the baffle plate 3" down from the top.  The photo has a "glare" from the flash which washes out some detail (at least I think it does).  Can you post a sketch or take another photo at a slight angle, or give a little better word description.

Thanks for sharing....
Ken