Method and apparatus for measuring the velocity of sound in a workpiece

Claim 2

Apparatus for measuring the velOcity of sound in a workpiece immersed in a liquid bath by the ultrasonic pulse-echo method comprising: a body of liquid; a transmit transducer and a receive transducer disposed in said body of liquid and spaced a predetermined distance (Dl) from one another; electrical circuit means coupled to said transmit transducer and said receive transducer for producing during a first time interval a first electrical signal (Tx) commensurate with the transit time of an ultrasonic pulse signal traversing said predetermined distance from said transmit transducer through said liquid to said receive transducer; and for producing during a second time interval during which a workpiece is disposed in said body of liquid and said transducers, separated by said distance, are acoustically coupled through said liquid to opposite sides of the workpiece a second electrical signal (Ta) commensurate with the transit time of an ultrasonic pulse signal from said transmit transducer through the liquid and workpiece to said receive transducer, and a third electrical signal (Tb) commensurate with one round trip transit time of the ultrasonic pulse signal in the workpiece; means for producing a fourth electrical signal commensurate with said predetermined distance (Dl); means for producing a control signal indicative of the presence and absence of a workpiece in said body of liquid for denoting the condition when providing said first, second and third signals, and computer means coupled for receiving said first, second, third and fourth signals and receiving also said control signal providing identification of said first, second and third signals for providing an output signal (Vs) commensurate with the velocity of the ultrasonic signal in the workpiece in accordance with the formula: Vs Dl(Tx - Ta + Tb/2)/Tx(Tb/2)

Claim 3

Apparatus for measuring the velocity of sound in a workpiece as set forth in claim 1, said electrical signals corresponding to Tx, Ta and Tb being produced as analog signals; means for receiving said analog signals and converting them to digital signals, and said computer means adapted to process digital signals.

Claim 4

Apparatus for measuring the velocity of sound in a workpiece as set forth in claim 1, said body of liquid comprising water.

Claim 5

Apparatus for measuring the velocity of sound in a workpiece immersed in a liquid bath by the ultrasonic pulse-echo method comprising: an enclosure; a body of liquid at least partially filling said enclosure; a transmit transducer and a receive transducer disposed in said body of liquid and spaced at a predetermined distance Dl from one another; means for disposing a workpiece whose velocity of sound is to be measured in the bath and spaced between said transducers; electrical pulse generating means coupled to said transmit transducer for causing said transmit transducer to cyclically send an ultrasonic pulse through said distance Dl to said receive transducer; electrical circuit means which include a gating means coupled to said transmit and receive transducers for producing during a time interval when no workpiece is disposed in said distance an electrical signal Tx commensurate with the transit time of the ultrasonic pulse through said distance, and for producing during a time interval when a workpiece is disposed in said distance electrical signals Ta and Tb commensurate respectively with the transit time of the ultrasonic pulse through said liquid and workpiece and to twice the transit time of the ultrasonic pulse through the workpiece dimension interposed in the path of said pulse from said transmit transducer to said receive transducer; circuit means which include pulse width to voltage converters coupled for receiving said electrical signals and providing in response thereto fUrther electrical signals whose amplitude is commensurate respectively with the values of Tx, Ta and Tb; means coupled for receiving said signal commensurate with Tb and processing it to produce a signal commensurate with Tb/2; analog to digital conversion means coupled for receiving the signals commensurate with Tx, Ta and Tb/2 and providing corresponding digital output signals; means for producing a digital signal whose amplitude is commensurate with said predetermined distance Dl; means for producing a control signal indicative of the presence and absence of a workpiece in said body of liquid and spaced between said transducers for denoting the condition when providing the respective signals Tx, Ta and Tb, and digital computing means coupled for receiving said digital output signals, said digital signal commensurate with the value Dl, and said control signal, and said computing means being adapted to provide and display a value Vs indicative of the velocity of sound in the workpiece by performing calculations in accordance with the equation: Vs Dl(Tx - Ta + Tb/2)/Tx(Tb/2)

Claim 6

Apparatus for measuring the velocity of sound in a workpiece immersed in a liquid bath by the ultrasonic pulse-echo method comprising: an enclosure; a body of liquid at least partially filling said enclosure; a transmit transducer and a receive transducer disposed in said body of liquid and spaced at a predetermined distance Dl from one another; means for disposing a workpiece whose velocity of sound is to be measured in the bath and spaced between said transducers; electrical pulse generating means coupled to said transmit transducer for causing said transmit transducer to cyclically send an ultrasonic pulse through said distance Dl to said receive transducer; electrical circuit means which include a gating means coupled to said transmit and receive transducers for producing during a time interval when no workpiece is disposed in said distance an electrical signal Tx commensurate with the transit time of the ultrasonic pulse through said distance, and for producing during a time interval when a workpiece is disposed in said distance electrical signals Ta and Tb commensurate respectively with the transit time of the ultrasonic pulse through said liquid and workpiece and to twice the transit time of the ultrasonic pulse through the workpiece dimension interposed in the path of said pulse from said transmit transducer to said receive transducer; circuit means which include pulse width to voltage converters coupled for receiving said electrical signals and providing in response thereto fUrther electrical signals whose amplitude is commensurate respectively with the values of Tx, Ta and Tb; means coupled for receiving said signal commensurate with Tb and processing it to produce a signal commensurate with Tb/2; analog to digital conversion means coupled for receiving the signals commensurate with Tx, Ta and Tb/2 and providing corresponding digital output signals; means for producing a digital signal whose amplitude is commensurate with said predetermined distance Dl; means for producing a control signal indicative of the presence and absence of a workpiece in said body of liquid and spaced between said transducers for denoting the condition when providing the respective signals Tx, Ta and Tb, and digital computing means coupled for receiving said digital output signals, said digital signal commensurate with the value Dl, and said control signal, and said computing means being adapted to provide and display a value Vs indicative of the velocity of sound in the workpiece by performing calculations in accordance with the equation: Vs Dl(Tx - Ta + Tb/2)/Tx(Tb/2)

Claim 9

A method for determining the velocity of sound in a workpiece as set forth in claim 5, said computing being performed digitally.

Claim 10

A method for determining the velocity of sound in a workpiece as set forth in claim 6, said acoustic signals being in the ultrasonic frequency range.