Hartzell Fan, a leading manufacturer of industrial air moving equipment, received notice from the United States Patent Office that Patent Application #7,494,325 on the Adjustable Pitch Aluminum Prop (AL Prop) has been approved. This patent is based on the shape, arrangement, and location of the ribs that go the length of the blades and how they reduce the sound generated in the lower octave bands.

The AL Prop is constructed of cast aluminum material (blades and hub) and is used in multiple products that include roof ventilators, panel fans, and duct axial fans. The adjustable prop is well suited for industrial air moving applications requiring high flow and low- to medium-pressure and is available in multiple blade configurations to allow precise selection by adjusting the blade angle. Some low-speed selections are available for installations where low sound levels must be maintained. Sound levels may be decreased by as much as 5 to 10 dBA for lower speed operation.

For more information, visit www.hartzellfan.com.