Ultrasound air velocity detector for HVAC ducts and method therefor

In combination with a duct carrying air flow for heat, ventilation or air conditioning, said duct subject to significant vibrations due to environmental factors, an air velocity detector utilizing spaced apart ultrasound transceivers comprising:

• a rigid support subassembly mounted in said duct, said rigid support subassembly substantially eliminating vibrations carried by said duct, said ultrasound transceivers mounted, in a spaced part relationship facing each other, on opposing end portions of said subassembly such that air, passing through said duct, crosses a sensory path laterally extending across said duct between said spaced apart transceivers;
• electronic circuitry coupled to said transceivers having:
• means for determining the phase difference between a transmitted ultrasound signal and a received ultrasound signal;
• means for calculating the velocity of the air flow in said duct based upon said phase difference;
• and,
• wherein said rigid support assembly includes a rigid, substantially straight member spanning said duct adjacent said sensory path, said transceivers mounted at opposite ends of said member near opposing walls of said duct.

In combination with a duct carrying air flow for heat, ventilation or air conditioning, an air velocity detector utilizing spaced apart ultrasound transceivers comprising:

• a rigid support subassembly mounted in said duct, said ultrasound transceivers mounted, in a spaced part relationship facing each other, on opposing end portions of said subassembly such that air, passing through said duct, crosses a sensory path laterally extending across said duct between said spaced apart transceivers;
• electronic circuitry coupled to said transceivers having:
• means for determining a representative phase difference signal between a transmitted ultrasonic signal from one transceiver and the corresponding received ultrasonic signal from the opposing transceiver;
• means for calculating the velocity of the air flow in said duct based upon said representative phase difference signal;
• and,
• wherein said rigid support assembly includes a rigid, substantially straight member spanning said duct adjacent said sensory path, said transceivers mounted at opposite ends of said member near opposing walls of said duct.

A method for determining air velocity in a duct carrying air flow for heat, ventilation or air conditioning utilizing spaced apart ultrasound transceivers, the method comprising the steps of:

• providing a rigid support spanning a defined volume in said duct which includes multiple cross-sectional areas of said duct;
• mounting said ultrasound transceivers, face to face, on opposing, laterally and longitudinally spaced apart regions of said rigid support such that a sensory path extends across and through said duct volume and said multiple cross-sectional areas between said spaced apart transceivers;
• electronically obtaining a phase difference representative signal based upon a transmitted ultrasonic signal and a corresponding received ultrasonic signal;
• and,
• electronically calculating the velocity of air flow in said duct based upon said phase difference representative signal.