Liquid-level gauging
First Claim
1. In an ultrasonic liquid level sensor of the kind including an ultrasonic transducer mounted towards the lower end of a tube so that ultrasonic energy from the transducer is directed upwardly along the length of the tube to a liquid/gas interface at which energy is reflected back to the transducer, said tube being mounted in a liquid reservoir and arranged to extend upwardly and to be filled with liquid to the same height as liquid outside the tube, the improvement wherein the tube is of a first, rigid material and has a surface layer along a major part at least of the length of the tube that is of a second material different from the first material, the second material being acoustically-absorbing and functioning to absorb ultrasonic energy and thereby damp the transmission of ultrasonic vibration from a wall of the tube into liquid within the tube.
5 Assignments
0 Petitions
Accused Products
Abstract
An ultrasonic liquid level sensor has a transducer mounted at the lower end of an aluminum tube that projects upwardly in a liquid tank so that the tube is filled with liquid to the same height as that outside the tube. Internally, the tube has a layer of an acoustically-absorbing plastics to damp the transmission of ultrasonic vibration from the wall of the tube into liquid within the tube.
19 Citations
10 Claims
- 1. In an ultrasonic liquid level sensor of the kind including an ultrasonic transducer mounted towards the lower end of a tube so that ultrasonic energy from the transducer is directed upwardly along the length of the tube to a liquid/gas interface at which energy is reflected back to the transducer, said tube being mounted in a liquid reservoir and arranged to extend upwardly and to be filled with liquid to the same height as liquid outside the tube, the improvement wherein the tube is of a first, rigid material and has a surface layer along a major part at least of the length of the tube that is of a second material different from the first material, the second material being acoustically-absorbing and functioning to absorb ultrasonic energy and thereby damp the transmission of ultrasonic vibration from a wall of the tube into liquid within the tube.
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10. An ultrasonic liquid level sensor comprising:
- an ultrasonic transducer;
means mounting a tube in a liquid reservoir with the tube extending upwardly so that the tube is filled with liquid to the same height as liquid in the reservoir outside the tube; and
means mounting the transducer at the lower end of the tube so that ultrasonic energy form the transducer is directed upwardly along the length of the tube to a liquid/gas interface at which energy is reflected back tot he transducer, the tube being of a metal and having an internal layer of an acoustically-absorbing plastics material that absorbs ultrasonic energy and thereby damps transmission of ultrasonic vibration from a wall of the tube into liquid within the tube.
- an ultrasonic transducer;
Specification