Liquid level sensor
AssigneeThe Whitaker Corporation
InventorRichard Hunter Brown
Life of this patent
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Abstract
The level of a liquid is detected by an ultrasonic arrangement comprising a transmitter and a receiver. The transmitter has a vertical array of transmitter segments which transmit sequentially, while the receiver is a single transducer. The transmitter and receiver are formed as a single assembly operating in pulse echo mode in conjunction with a passive reflector. The difference in transmission time in liquid and gas allows a digital, depth representative output to be generated. The transmitter is formed by securing a single sheet of piezo polymer film over a printed circuit board having a conductive pattern defining the segments.
Claims25
A liquid level sensor device comprising a transmitter and a receiver of ultrasonic energy, the transmitter for transmitting pulses to the receiver along a transmission path of known length, and adapted to be positioned in a liquid container such that liquid in the container is present in the transmission path, the transmitter comprising a plurality of individually addressable independent segments spaced apart in the direction of liquid depth, the segments comprising conductive signal electrodes, where the transmitter and receiver are formed as a single assembly operating in pulse-echo mode in conjunction with a passive reflector in the transmission path.
A liquid level sensor device comprising a transmitter and receiver of ultrasonic energy;
- the transmitter for transmitting pulses to the receiver along a transmission path of known length, and adapted to be positioned in a liquid container such that liquid in the container is present in the transmission path, the transmitter comprising a plurality of individually addressable independent segments spaced apart in the direction of liquid depth, the segments comprising conductive signal electrodes, wherein the transmitter comprises a patterned substrate, and a piezoelectric matrix mounted thereon.
A liquid level sensor device comprising a transmitter and receiver of ultrasonic energy, the transmitter for transmitting pulses to the receiver along a transmission path, the device to be positioned in a liquid container such that liquid in the container is present in the transmission path, wherein the receiver comprises a piezoelectric material patterned to form two independent active area segments, each segment having a width that varies along the liquid height in a manner differing from the other such that the ratio of signal strengths of one segment with respect to the other varies dependent on the liquid height.
Dependencies are inferred from the claim text.