Patent ID: 7454972

Claim:
A method for weighing a moving load moving over a load bearing medium, comprising: sending a first acoustic wave from a source acoustic transducer, attached to or embedded in the loading bearing medium, through the load bearing medium in an unloaded state; detecting the first acoustic wave at a receiving acoustic transducer, attached to or embedded in the loading bearing medium, wherein an acoustic path is defined in the load bearing medium between the source and receiving transducers; determining a first acoustic wave propagation time delay associated with the acoustic path in an unloaded state based on the sending and detecting of the first acoustic wave; when the acoustic path is loaded by a moving load supported by the medium, sending and detecting a second acoustic wave from the source acoustic transducer to the receiving acoustic transducer; determining a second acoustic wave propagation time delay associated with the acoustic path in a loaded state based on the sending and detecting of the second acoustic wave; determining an acoustic propagation time delay difference between the first and second acoustic wave propagation time delays for the unloaded and loaded states; and determining a weight or mass of the moving load based on the acoustic propagation time delay difference.