Patent ID: 6039541
Filing Date: 2000-03-21
Classification: F04D,F24F

Abstract:
A ceiling fan blade for low speed operation at approximately 50 to approximately 200 revolutions per minute(rpm) for use in overhead ceiling fan systems, the blade comprising:a positive twist adjacent to a rotor end of the blade, so that blade pitch increases from a tip end of the blade to the rotor end of the blade;an airfoil having a thicker portion at the rotor end tapering down to a thinner portion at the tip end, for providing high lift and low drag; anda blade chord having a wider portion from the rotor end tapering down to a narrower portion at the tip end, wherein the blade is operated in a ceiling fan running at low speed ranges of approximately 50 to approximately 200 revolutions per minute(rpm) for use with ceiling fan systems, and provides substantial energy savings and increased air flow over conventional ceiling blades.