Small cyclone airflow readings

[James Gunning]

I purchased a digital anemometer a few months ago but couldn't get at the cyclone to take some readings with it. Finally did that today.

This is my dust collection setup. It is a metal SDD with a 1HP Penn State blower on it. The impeller is 10" in diameter. I have a 9 foot long piece of 6" flex hose that hooks up to the individual machine when in use. I took the anemometer reading at the end of the flex hose to see what the blower is pulling at the machines. I held the anemometer in the center of the duct and flat across the end of it. The reading in CFM was 500+- 20 CFM at the end of the flex duct. Airspeed was 4000-4200 feet per minute. Both readings were in the ballpark of what I thought I would get. The CFM is actually a bit higher than I expected. I realize this isn't the most scientific method and the Chinese instrument not the height of available technology. I bought the anemometer mostly to get a relative sense of what changes to my system would give me in airflow.

SDD-PS%20blower-Wynn%20filter.jpg

Anemometer.jpg

[Andy Giddings]

Good looking remodel James. From what I can tell your cyclone and impeller rotation are in the same direction which will make your mods efficient. Is your impeller inlet 6 inch diameter? It looks from your results as if the impeller diameter and motor are limiting your CFM and 500 may be the best you can get, although the long flex will drop it a little. How is your cyclone performing in terms of dust making it through to the filter?

[James Gunning]

Andy,

The inlet to the blower is indeed 6" to match the SDD. I made a "donut" with a smoothly rounded intake out of MDF that replaced the original side plate that had a 5" inlet. The rotation of both the cyclone and impeller are the same. I intend to make an air straightener and try it to see if there is any improvement. From my research, the air straightener should help no matter the rotation. No doubt the impeller size and motor are what is keeping me from more than 500 CFM or so. Actually, I'm glad it's at least that. The reading is taken at the end of the flex hose, so the loss from that is accounted for. When I don't let the bin fill up, see: http://www.sawmillcreek.org/showthre...in!!&highlight= the cyclone does a good job with the fines. I find the bulk in the bin and after a filter blowdown, usually just enough to cover the bottom of the filter bucket. Collection from my machines is very good, but clearly not at Clearvue standards.

[Randall J Cox]

Very nice setup. Looks like you did everything right to me. Good numbers for 1 hp.

[Larry Frank]

I tried using the same anemometer and got some numbers with a lot of variation. Holding it at various positions and distances caused large changes. In my case, I think it gives too large a number. But it is better than not having any idea.

[James Gunning]

Larry,

I had the same reading variable if I didn't hold the instrument steady and exactly perpendicular to the duct. The readings seemed not to be as sensitive to having it in the center. Reading with it along the side of the duct, gave about the same values as right in the center. Once I figured out how to hold it steady and in the proper position, the readings stabilized. They do fluctuate a bit, and that's why I put 500 +- 20. The values were about what I expected, so I think they are fairly accurate. What I really want is to measure the airflow as changes are made to see if things improve or get worse.