US 5,624,188 AGranted

Acoustic thermometer

OwnerDavid A. Westinventor

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Abstract

A thermometer using the temperature dependance of the speed of sound, measures the average temperature along a path traversing an open environment containing a medium. A transmitting transducer, coupled to a signal generator and placed at a first point in the medium, produces a burst of sound of predetermined frequency and duration. The sound burst travels through the medium to a second point, located a predetermined distance from the first. At the second point, a passive sound reflector, or an active apparatus, produces a returning sound burst. A receiving transducer, positioned close to the transmitting transducer, receives the returned sound. A detection circuit, coupled to the receiving transducer, indicates the presence of the returned sound burst. A timer, with connections to the signal generator and the detection circuit, measures the elapsed time for the round trip of the sound. The resulting time measurement is an indicator of the average temperature along the path between the first and second points. This time measurement is output for use by an electronic system, or processed to represent temperature directly.

Claims18

Dependent claims

A thermometer for measuring average temperature based on measurement of the time required for sound to traverse a path of predetermined length through an open environment, the environment being composed of a medium capable of supporting the propagation of sound waves, the measured time being an indicator of the average temperature of the medium along the path of the sound, the thermometer comprising:

means for generating an electrical signal burst of predetermined frequency and duration, and for modualting the signal burst to convey an identity code;
a sound transmitting transducer for converting the electrical signal burst into a sound burst, the sound burst having substantially the same frequency and duration as the electrical signal burst and conveying the identity code, the transmitting transducer being connected to the generating means and positioned to transmit the sound burst along the path through the medium;
a sound receiving transducer for receiving a reflection of the sound burst and converting the reflected sound burst into a received electrical signal, the reflection being returned from a predetermined distance on the path, the receiving transducer being positioned proximate to the transmitting transducer,
means for detecting the presence of the received electrical signal having the identity code, the detecting means having an input connected to the sound receiving transducer and having an output for indicating the presence of the received electrical signal;
and
a timer, connected to the generating means and to the output of the detecting means, for measuring elapsed time between the generation of the electrical signal and the indication of the detection of the received electrical signal having the identity code, the timer further having an output connection for communicating information related to the elapsed time measurement.

3 more elements

means for generating an electrical signal burst of predetermined frequency and duration, and for modulating the signal burst to convey an identity code;
a sound transmitting transducer for converting the electrical signal burst into a sound burst, the sound burst having substantially the same frequency and duration as the electrical signal burst and conveying the identity code, the transmitting transducer being connected to the generating means and positioned to transmit the sound bursts along the path through the medium;
means for returning the sound burst, located in the path at predetermined distance from, and returning the sound burst substantially toward, the transmitting transducer;
a sound receiving transducer for receiving and converting the returned sound burst into a received electrical signal, the receiving transducer being positioned proximate to the transmitting transducer;
means for detecting the presence of the received electrical signal having the identity code, the detecting means having an input connected to the sound receiving transducer and having an output for indicating the presence of the received electrical signal;
and
a timer, connected to the generating means and to the output of the detecting means, for measuring elapsed time between the generation of the electrical signal burst and the indication of the detection of the received electrical signal having the identity code, the timer further having an output connection for communicating information related to the elapsed time measurement.

4 more elements

Dependencies are inferred from the claim text.