Apparatus for determination of probe contact with a liquid surface
First Claim
1. Apparatus for detecting the occurrence of physical contact between a conductive probe and a surface of a liquid held in a container as the probe is moved toward and eventually touches the liquid surface, the apparatus comprising:
- a conductor disposed on the other side of said container from said probe,signaling circuitry for sending an electrical signal through said liquid between said conductive probe and said conductor, and for detecting when said physical contact has occurred based on when the resulting electrical signal which has passed through said liquid exceeds a threshold, anda threshold determiner for establishing said threshold based on said resulting electrical signal.
3 Assignments
0 Petitions
Accused Products
Abstract
The occurrence of physical contact between a conductive probe and a surface of a liquid held in a container is detected as the probe is moved toward and eventually touches the liquid surface; a conductor is disposed on the other side of the container from the probe; an electrical signal is sent through the liquid between the conductive probe and the conductor, and the time when physical contact has occurred is determined based on when the resulting electrical signal which has passed through the liquid exceeds a threshold; and the threshold is determined based on the resulting electrical signal. In another aspect, the electrical signal is pulsed, and the resulting electrical signal is synchronously detected as the basis for determining when the physical contact has occurred. In another aspect, a non-conductive rotatable support holds the container and moves the container into position under the probe; a conductor is disposed beneath the rotatable support and in a fixed position relative to the rotatable support so that when the container is in position under the probe, the conductor lies beneath the container; the conductor has a limited extent so that when the container is not in that position no part of the conductor lies beneath the container.
60 Citations
23 Claims
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1. Apparatus for detecting the occurrence of physical contact between a conductive probe and a surface of a liquid held in a container as the probe is moved toward and eventually touches the liquid surface, the apparatus comprising:
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a conductor disposed on the other side of said container from said probe, signaling circuitry for sending an electrical signal through said liquid between said conductive probe and said conductor, and for detecting when said physical contact has occurred based on when the resulting electrical signal which has passed through said liquid exceeds a threshold, and a threshold determiner for establishing said threshold based on said resulting electrical signal. - View Dependent Claims (2, 3, 4)
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5. Apparatus for detecting the occurrence of physical contact between a conductive probe and a surface of a liquid held in a container as the probe is moved toward and eventually touches the liquid surface, the apparatus comprising:
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a conductor disposed on the other side of said container from said probe; and circuitry for sending a pulsed electrical signal through said liquid between said conductive probe and said conductor while said probe is being moved, and for synchronously detecting the resulting electrical signal as the basis for determining when said physical contact has occurred. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12)
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13. A method for detecting the occurrence of physical contact between a conductive probe and a surface of a liquid held in a container as the probe is moved toward and eventually touches the liquid surface, the method comprising:
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sending an electrical signal through said liquid between said conductive probe and a conductor disposed on the other side of said container from said probe while said probe is being moved, determining a threshold based on the resulting electrical signal which has passed through said liquid, and detecting when said physical contact has occurred based on when said resulting electrical signal exceeds said threshold. - View Dependent Claims (14, 15, 16)
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17. A method for detecting the occurrence of physical contact between a conductive probe and a surface of a liquid held in a container as the probe is moved toward and eventually touches the liquid surface, the method comprising:
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sending a pulsed electrical signal through said liquid between said conductive probe and a conductor disposed on the other side of said container from said probe, and synchronously detecting the resulting electrical signal as the basis for determining when said physical contact has occurred. - View Dependent Claims (18, 19)
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20. Apparatus for detecting the occurrence of physical contact between a conductive probe and a surface of a liquid held in a container as the probe is moved toward and eventually touches the liquid surface, the apparatus comprising:
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a non-conductive rotatable support for holding said container and moving said container into position under said probe, a conductor disposed beneath said rotatable support and in a fixed position relative to said rotatable support so that when said container is in said position said conductor lies beneath said container and on the other side thereof from said probe, said conductor having a limited extend so that when said container is not in said position no part of said conductor lies beneath said container, and circuitry for sending a pulsed electrical signal through said liquid between said conductive probe and said conductor while said probe is being moved, and for synchronously detecting the resulting electrical signal as the basis for determining when said physical contact has occurred. - View Dependent Claims (21, 22, 23)
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Specification