Fluid monitor system and method using a resonator
First Claim
1. A system for detecting the presence of a selected substance located in a container, the system comprising:
- an open resonator having a selected characteristic that changes in response to the selected substance;
a circuit coupled to the open resonator that is responsive to the selected characteristic of the open resonator and that provides an output signal that varies in dependence on said selected characteristic of the open resonator;
a mounting structure arranged to mount the open resonator at a position outside the container and such that the existence of the selected substance in the container will change said characteristic of the open resonator; and
a processor that receives the output signal of the circuit and determines the change in the output signal that is based on the change in the selected characteristic of the open resonator to detect the presence of the selected substance in the container.
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Accused Products
Abstract
A non-invasive, fluid monitor engages an open resonator with a segment of fluid line. The fluid line is disposed such that it and the fluid within become a part of the dielectric loading on the resonator. The open resonator is a part of an oscillator circuit that changes frequency of oscillation in response to the dielectric loading on the resonator. A frequency discriminator monitors the frequency of the oscillator to detect an air bubble in the fluid line. In the case where the resonator comprises a microstrip line, the microstrip line is disposed in parallel to the segment of the fluid line and the length of the microstrip line is selected to be equal to or greater than the maximum length of air bubble permitted thus providing a volumetric air-in-line sensor. The output of the frequency discriminator is compared to a threshold to determine a frequency shift large enough to indicate the presence of an air bubble.
42 Citations
27 Claims
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1. A system for detecting the presence of a selected substance located in a container, the system comprising:
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an open resonator having a selected characteristic that changes in response to the selected substance; a circuit coupled to the open resonator that is responsive to the selected characteristic of the open resonator and that provides an output signal that varies in dependence on said selected characteristic of the open resonator; a mounting structure arranged to mount the open resonator at a position outside the container and such that the existence of the selected substance in the container will change said characteristic of the open resonator; and a processor that receives the output signal of the circuit and determines the change in the output signal that is based on the change in the selected characteristic of the open resonator to detect the presence of the selected substance in the container. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for detecting the presence of a selected substance located in a container, the method comprising the steps of:
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disposing an open planar resonator at a position outside the container such that the existence of the selected substance in the container will change a selected characteristic of the open resonator; providing an output signal from a circuit coupled to the open resonator that is responsive to the selected characteristic of the open resonator such that the output signal varies in dependence on said characteristic of the open resonator; and processing the output signal of the circuit to determine the change in the output signal that is based on the change in the selected characteristic of the resonator to detect the presence of the selected substance in the container. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A system for detecting the presence of a selected substance in fluid located in a fluid line segment, the system comprising:
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an open planar resonator having a selected characteristic that changes in response to the selected substance; a circuit coupled to the open resonator that is frequency dependent on the selected characteristic of the open resonator and that provides an output signal that varies in dependence on the frequency of the circuit; a mounting structure arranged for mounting the open resonator at a position outside the container and such that the existence of the selected substance in the fluid line segment will change the characteristic of the open resonator; and a processor that receives the output signal of the circuit and determines the change in the frequency of the output signal that is based on the change in the selected characteristic of the open planar resonator to detect the presence of the selected substance in the fluid line segment. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27)
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Specification