Parker-hannifin Corporation

Parker-hannifan Plc

Martin Hewitt

Howard Austerlitz

A fluid level sensor for determining a fluid level within a container, includes a transducer for generating sonic or ultrasonic waves and a wave guide. The wave guide has a first end operatively coupled to the transducer and a second end for immersion into the fluid, the second end spaced a predetermined distance from the first end, wherein a gap is formed between the first end and the second end. The sensor can be used to measure a fluid level using both an impedance mismatch signal and a fluid conductance signal.

Ultrasonic fluid level sensor

A multi-frequency ultrasonic liquid level gauging system includes a storage apparatus for storing a volume of liquid and a plurality of ultrasonic transducers. Each transducer introduces a distinct ultrasonic signal into storage apparatus and receives a reflected signal back. A circuit drives and receives signals from the ultrasonic transducers. A processor calculates the liquid level at each of the locations of ultrasonic transducers based on the reflected signal received from each transducer. Transducers are connected in parallel, thereby allowing circuit to communicate to the transducers through a single conductive path. A method of measuring a liquid level in storage apparatus includes emitting a single drive signal to a plurality of ultrasonic signal sources, wherein each source is operable to transmit ultrasonic signals having unique frequencies. The ultrasonic signals are transmitted through liquid and each is reflected at the liquid surface. The reflected signals also have unique frequencies and are communicated to processor. The reflected signals are distinguished and the depth of the liquid level at various storage apparatus locations is calculated from each of the distinguished reflected signals. The depth of liquid is a function of the propagation time of each signal through the liquid.

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Selden, NY, United States of America

Martin Hewitt