초록 ▼

A time gate ultrasonic sensor measures a physical property of a material, such as the presence of the material, within a defined space. The sensor includes at least one transducer connected to a support structure and positioned generally adjacent the defined space for transmitting and receiving ultr

A time gate ultrasonic sensor measures a physical property of a material, such as the presence of the material, within a defined space. The sensor includes at least one transducer connected to a support structure and positioned generally adjacent the defined space for transmitting and receiving ultrasonic signals across the defined space. The ultrasonic signals include a main waveform which travels across the defined space and a self-test waveform which travels along the support structure. The sensor monitors the received ultrasonic signals during a main time window to sense whether the main waveform is present in the received signals. The sensor senses the physical property of the material within the defined space as a function of whether the main waveform is present within the time window. The sensor performs a self-test each measurement cycle by determining whether the self-test waveform is present during a self-test time window which is different from the main time window.

대표청구항 ▼

An ultrasonic sensor for detecting presence of a liquid within a defined gap, the sensor comprising: a support structure; a transmit signal source configured for generating a transmit signal; transducer means, connected to the support structure and to the transmit signal source, the transducer means

An ultrasonic sensor for detecting presence of a liquid within a defined gap, the sensor comprising: a support structure; a transmit signal source configured for generating a transmit signal; transducer means, connected to the support structure and to the transmit signal source, the transducer means positioned adjacent the gap for transmitting ultrasonic signals in response to the transmit signal (a) across the gap and through the liquid if the liquid is present within the gap to define a main waveform and (b) through the support structure to define a self-test waveform, and for receiving the transmitted ultrasonic signals after the signals travel through the gap and through the support structure; means for defining a self-test time window relative to the transmit signal and to an acoustic velocity of the self-test waveform through the support structure; and means for monitoring the received ultrasonic signals that define the self-test waveform during the self-test time window; means for determining whether the self-test waveform is present within the self-test time window and for generating a self-test output indicative of sensor integrity as a function of whether the self-test waveform is present with the self-test time window; time gate means, coupled to the transmit signal source, for receiving the transmit signal and for defining a main time window relative to the received transmit signal and to an acoustic velocity through the liquid; means, coupled to the transducer means and to the time gate means, for monitoring the received ultrasonic signals during the main time window; and means, coupled to the means for monitoring, for determining whether the main waveform is present within the main time window and for generating a main waveform output indicative of whether the liquid is present within the gap as a function of whether the main waveform is present within the main time window.