Chemical analyzer using RF radiation attenuation measurements
First Claim
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1. An apparatus for analyzing a sample, comprising:
- means for generating a first signal of radio frequency electromagnetic radiation;
a transmitting antenna electrode, selectively coupled to said generating means, for directing a first signal along a first path passing through a volume element of a sample to produce a second signal;
a receiving antenna electrode for receiving said second signal;
means, coupled to said receiving antenna electrode, for measuring on the basis of said second signal the degree to which said first path attenuates said first signal over a defined interval of time; and
means, responsive to said measuring means, for correlating the rate of change in attenuation of the first signal to chemical changes occurring in the sample itself.
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Abstract
A chemical analyzer in which the measurement of the change in attenuation of RF radiation propagated through a sample is used as the basis for calculating the change in concentration of a given chemical in the sample. Also disclosed are various probe and system designs which facilitate the use of RF attenuation as a basis for measurement of certain chemical characteristics of a sample.
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Citations
43 Claims
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1. An apparatus for analyzing a sample, comprising:
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means for generating a first signal of radio frequency electromagnetic radiation; a transmitting antenna electrode, selectively coupled to said generating means, for directing a first signal along a first path passing through a volume element of a sample to produce a second signal; a receiving antenna electrode for receiving said second signal; means, coupled to said receiving antenna electrode, for measuring on the basis of said second signal the degree to which said first path attenuates said first signal over a defined interval of time; and means, responsive to said measuring means, for correlating the rate of change in attenuation of the first signal to chemical changes occurring in the sample itself. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An apparatus for analyzing a sample, comprising:
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means for generating a first signal of amplitude stabilized radio frequency electromagnetic radiation; means for propagating said radio frequency electromagnetic radiation along a known path through a sample; means for inducing a change of concentration of at least one chemical component in said sample for which a change in concentration induces a change in attenuation of said first signal as it is propagated through the sample; means for repetitively measuring the amplitude of said radio frequency signal over defined, short intervals after it has traversed said known path through said sample; and means for determining on the basis of the measured amplitude a rate of change of concentration of said at least one chemical component. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. An apparatus for analyzing a sample, comprising:
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a source of RF radiation; a cell, switchably connected to said RF source and for applying said RF radiation to a volume element of a sample; a calibration source, switchably connected to said RF source, for producing a known attenuation in said RF radiation when said RF radiation is applied to said calibration source; receiving means, coupled to said cell and said calibration source, for receiving attenuated RF radiation which has traversed one of said volume element and said calibration source, and for producing analog signals indicative of the magnitude of said attenuated RF radiation; means, coupled to said receiving means, for converting said analog signals to digital signals; calculating means, coupled to said converting means, for determining which of said cell and said calibration source is connected to said RF source, for computing the rate of change of attenuation of said RF radiation by said volume element on the basis of digital signals, for determining a change in concentration of at least one component of said volume element on the basis of said computed attenuation; and means, responsive to said calculating means, for displaying results of said computing. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39)
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40. A method of analyzing a sample, comprising the steps of:
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(a) generating a first signal of radio frequency electromagnetic radiation; (b) direction said first signal along a path passing through a volume element of a sample; (c) measuring the rate of change of attenuation of said first signal as said first signal propagates along said path, and (d) determining a concentration of a chemical constituent in said volume element on the basis of the rate of change in said attenuation measured in said step (c). - View Dependent Claims (41, 43)
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42. A method of analyzing a sample, comprising the steps of:
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(a) generating a first signal of amplitude stabilized radio frequency electromagnetic radiation; (b) propagating said first signal radiation along a known path through a sample; (c) inducing a change of concentration of at least one chemical component of said sample for which a change in concentration induces a change in attenuation of the first signal; (d) measuring as said change of concentration occurs an amplitude of said first signal after it has traversed said known path; (e) repeating said step (d) to determine a rate of change of attenuation of said first signal; and (f) determining a change in concentration of said component on the basis of said rate of change of attenuation.
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Specification