Several months ago, I purchased the Super Dust Gorilla 5 HP from Oneida. The specifications on the Super Dust Gorilla were
• 5 HP US made Baldor motor – 19.5 Amps
• Backward Inclined Cast Aluminum Impeller – 15”
• Max Performance 1860 CFM at 2.5” SP
• 8” Inlet
• HEPA MERV 16+ Filter
• Filter 110 sq. ft
Given my new dust collector, I wanted to see how well it really performed compared to the Oneida performance curve. I used a great set of tools loaned to me from another woodworker—-
• Dwyer 471 Digital Thermal Anemometer
• UEi 151 Digital Manometer
• Clamp ammeter.
To do the testing, I installed two 24” lengths of 8” duct to the 8” inlet of the dust collector. I also built a cone to insert into the end of the duct using an 8” funnel mounted on a ½” threaded rod with a handle on the end. (It would have been much better to have a longer length of straight 8” duct. However, with my dust collector in its current position, this was not possible.)
All of the testing was done in one location as shown in the following schematic.
The flow through the dust collector was controlled by using a funnel which could be adjusted in and out of the 8” duct. It was easy to set up various conditions and collect the data.
The instrument used to measure the flow was the Dwyer 471 Thermal Digital Anemometer. The probe was inserted through a small hole in the bottom of the duct and then flow measurements were taken at six points across the diameter of the duct. The locations of these measurements were determined from the literature and used to make standardized measurements. To insure that the measurements were taken in the same place and were repeatable, a stand was built to hold the probe and properly position it.
There are two holes in the tip of the probe. One is the hot wire anemometer and the other measures temperature. The probe must be kept perpendicular to the air flow to get good readings. The static pressure was measured close to the flow measurements and done with the UEi 151 digital manometer.
Measurements were taken at full open and full close of the duct and at intervals of 1” H2O static pressure. The entire set of measurements was repeated to assure that I had good data.
The data was plotted on a graph along with the data from the Oneida website. My measurements (diamonds) were lower than those provided by Oneida (squares) by about 200 cfm at maximum air flow. While the flow rates are very good, I expected my data to be closer to the Oneida data and have written them to determine what might cause the difference.
Velocity measurements ranged from 1100 fpm to 4700 fpm in the 8” duct.
Current measurements were made with the clamp ammeter for maximum air flow and for no air flow.
• Fully closed with minimum air flow – 7.2 amps
• Fully open with maximum air flow of 1650 cfm – 12.5 amps
I made measurements of the filter pressure and static pressure and various flow rates. Filter pressure ranged from about 0.5” at high static pressure with low flow rates and about 3.0” at low static pressure with high flow rates. This gives me a baseline for knowing when my filter is dirty.
There are a number of people who measure pressure on the filter side of the dust collector….between the filter and the impeller. This lets them have an idea of when the filter is getting dirty and needs to be cleaned.
At high flow rates, the filter pressure is higher than I would think best for the system and maybe a result of a smaller filter than some other similar dust collectors. This high filter pressure could lower the maximum achieved flow rates.