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US5120648A
Expired / Lapsed
US
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Chemical analyzer using rf radiation attenuation measurements
Assignee: LIM TECHNOLOGY LABORATORIES Inc 409 E MAIN ST RICHMOND VA 23219 A VA CORP
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Filing: 1988-05-26
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Granted: 1992-06-09
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Expires: 2008-05-26
Abstract
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.
Inventors
- 👤 Franklin Lim
- 👤 William H. Bingham
- 👤 Richard D. Moss
- 👤 Lloyd T. Hall, III
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:27
CPC Classifications
G; G01; G01N; G01N22/00
Claims Analysis
Total Claims: 48
Claim 1
Independent Claim
119 words
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.
Claim 2
Independent Claim
119 words
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.
Claim 3
Dependent Claim
67 words
An apparatus as claimed in claim 1, further comprising means, selectively coupled to said generating means, for directing said first signal along a second path of known attenuation, to produce a calibration signal, and wherein said measuring means is arranged to receive said calibration signal and is further for measuring with reference to said calibration signal, said degree to which said first path attenuates said first signal.
Claim 4
Dependent Claim
53 words
An apparatus as claimed in claim 1, wherein said means for correlating comprises calculating means, and wherein said measuring means provides data on the rate of change in attenuation of the first signal to said calculating means which determines from stored algorithms a characteristic of the chemical composition of the sample being tested.
Claim 5
Dependent Claim
44 words
An apparatus as claimed in claim 3, wherein said calculating means comprises a microprocessor and memory means for retaining a conversion information table containing information correlating the rate of change in attenuation of the first signal with concentration of a chemical in said sample.
Claim 6
Dependent Claim
43 words
An apparatus as claimed in claim 1, wherein said correlating means is further for calculating a concentration of a chemical in said sample, based on said measured degree to which said first path attenuates said first signal over said defined interval of time.
Claim 7
Dependent Claim
45 words
An apparatus as claimed in claim 5, wherein said correlating means provides a signal indicative of said concentration, and further comprising display means, coupled to said correlating means, for producing a visual indication of said concentration in response to a signal from said correlating means.
Claim 8
Dependent Claim
50 words
An apparatus as claimed in claim 5, further comprising a temperature sensing means, arranged to sense the temperature of the sample, for providing an indication of said sensed temperature to said correlating means and wherein said correlating means is further for calculating said concentration additionally with reference to said indication.
Claim 9
Dependent Claim
34 words
An apparatus as claimed in claim 1, further comprising cell means for maintaining a volume element of said sample within a few centimeters of at least one of said transmitting and receiving antenna electrodes.
Claim 10
Dependent Claim
67 words
An apparatus as claimed in claim 8, wherein said cell means has an outer wall and wherein said transmitting antenna electrode means comprises at least one first antenna electrode disposed coaxially with and on said outer wall, and wherein said receiving means comprises at least one second antenna electrode, disposed on and coaxially with said outer wall, and axially adjacent said at least one first antenna electrode.
Claim 11
Dependent Claim
33 words
An apparatus as claimed in claim 8, wherein said cell means comprises a well and said transmitting and receiving antenna electrodes are disposed on an outer surface of the bottom of said well.
Claim 12
Dependent Claim
18 words
An apparatus as claimed in claim 10, wherein said well and transmitting and receiving antenna electrodes are rectangular.
Claim 13
Dependent Claim
30 words
An apparatus as claimed in claim 10, wherein said well is cylindrical and wherein said pair of transmitting and receiving antenna electrodes is formed as a concentric ring and disk.
Claim 14
Dependent Claim
46 words
An apparatus as claimed in claim 8, wherein said cell means comprises a tube-shaped member having an antenna electrode disposed on a longitudinal surface thereof, and a rod-shaped member dimensioned to be disposed within said tube-shaped member and having one or more radiating surfaces arranged thereon.
Claim 15
Dependent Claim
38 words
An apparatus as claimed in claim 13, wherein said tube-shaped member is closed at one axial end, and wherein said rod-shaped member is provided with a stopper means for sealing the other axial end of said tube-shaped member.
Claim 16
Dependent Claim
30 words
An apparatus as claimed in claim 1, further comprising cell means for physically isolating at least one of said transmitting antenna electrode and said receiving antenna electrode from said sample.
Claim 17
Dependent Claim
25 words
An apparatus as claimed in claim 15, wherein said cell means comprises a tube-shaped member sealed at both ends and surrounding said transmitting antenna electrode.
Claim 18
Dependent Claim
32 words
An apparatus as claimed in claim 1, further comprising a shield for preventing environmental radio frequency radiation from interfering with transmission of said first signal or with reception of said second signal.
Claim 19
Dependent Claim
12 words
An apparatus as claimed in claim 17, wherein said shield is grounded.
Claim 20
Dependent Claim
39 words
An apparatus as claimed in claim 17, further comprising means, connected to said shield, for driving said shield to actively prevent environmental radio frequency radiation from interfering with transmission of said first signal or reception of said second signal.
Claim 21
Independent Claim
122 words
An apparatus for analyzing a sample, comprising: 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.
Claim 22
Independent Claim
122 words
An apparatus for analyzing a sample, comprising: 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.
Claim 23
Dependent Claim
52 words
An apparatus as claimed in claim 20, wherein said generating means is for generating said first signal to have a frequency selected to cause an active region of change in attenuation, wherein attenuation varies nearly linearly as a function of concentration, to occur within an anticipated range of said change in concentration.
Claim 24
Dependent Claim
24 words
An apparatus as claimed in claim 20, wherein said generating means is frequency-variable for generating said first signal over a predetermined range of frequencies.
Claim 25
Dependent Claim
24 words
An apparatus as claimed in claim 20, wherein said propagating means comprises an absorbent medium for absorbing and immobilizing a quantity of said sample.
Claim 26
Dependent Claim
32 words
An apparatus as claimed in claim 20, wherein said propagating means comprises a transmitting antenna electrode and a receiving antenna electrode arranged to couple radio frequency radiation primarily along said known path.
Claim 27
Dependent Claim
15 words
An apparatus as claimed in claim 20, wherein said change inducing means comprises an enzyme.
Claim 28
Dependent Claim
31 words
An apparatus as claimed in claim 25, further comprising a cell for defining a volume element of said sample, and wherein said enzyme is immobilized on a wall of said cell.
Claim 29
Dependent Claim
20 words
An apparatus as claimed in claim 20, wherein said change inducing means comprises means for exposing said sample to light.
Claim 30
Dependent Claim
20 words
An apparatus as claimed in claim 20, wherein said change inducing means comprises means for changing pressure of said sample.
Claim 31
Dependent Claim
23 words
An apparatus as claimed in claim 20, wherein said determining means comprises a microprocessor and a memory for storing a conversion information table.
Claim 32
Independent Claim
196 words
An apparatus for analyzing a sample, comprising: 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.
Claim 33
Independent Claim
196 words
An apparatus for analyzing a sample, comprising: 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.
Claim 34
Dependent Claim
56 words
An apparatus as claimed in claim 30, wherein said cell comprises: means for retaining said sample; transmitting electrode means for transmitting antenna and focusing said RF radiation through a volume element of said sample; and receiving antenna electrode means for receiving said RF radiation after said RF radiation has traversed said volume element of said sample.
Claim 35
Dependent Claim
68 words
An apparatus as claimed in claim 31, wherein retaining means is substantially cylindrical, wherein said transmitting antenna electrode means comprises a first array of ring-shaped electrodes each surrounding a respective axial portion of said retaining means, and wherein said receiving antenna electrode means comprises a second array of ring-shaped antenna electrodes each surrounding a respective axial portion of said retaining means, said first and second array being interdigitated.
Claim 36
Dependent Claim
55 words
An apparatus as claimed in claim 30, further comprising a temperature sensor, arranged to sense temperature of said sample and for generating a temperature signal indicative of the sensed temperature, and wherein said calculating means is coupled to said temperature sensor, and is further for determining said concentration with reference to the sensed sample temperature.
Claim 37
Dependent Claim
38 words
An apparatus as claimed in claim 30, further comprising means, coupled to said converting means and responsive to said calculating means for amplification of said attenuated RF radiation which has passed through said volume element of said sample.
Claim 38
Dependent Claim
39 words
An apparatus as claimed in claim 30, further comprising means, coupled to said converting means and responsive to said calculating means, for determining a zero level for said converting means and wherein said calculating means is also for autozeroing.
Claim 39
Dependent Claim
29 words
An apparatus as claimed in claim 30, further comprising means, coupled to said converting means and responsive to said calculating means, for determining a calibration of said converting means.
Claim 40
Dependent Claim
49 words
An apparatus as claimed in claim 30, further comprising: first switch means, interposed between said source of RF radiation and said cell, and responsive to said calculating means, for controlling connection between said source of RF radiation and said cell in response to a signal from said calculating means.
Claim 41
Dependent Claim
50 words
An apparatus as claimed in claim 37, further comprising second switch means, interposed between said source of RF radiation and said calibration source, and responsive to said calculating means, for controlling connection between source of RF radiation and said calibration source in response to a signal from said calculating means.
Claim 42
Dependent Claim
25 words
An apparatus as claimed in claim 30, further comprising means, responsive to said calculating means, for providing a visual indication of said change in concentration.
Claim 43
Independent Claim
85 words
A method of analyzing a sample, comprising the steps of: (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).
Claim 44
Independent Claim
85 words
A method of analyzing a sample, comprising the steps of: (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).
Claim 45
Dependent Claim
35 words
A method of analyzing a sample as claimed in claim 40, further comprising the additional steps after said step (d) of: (e) providing a visual display indicative of the concentration calculated in said step (d).
Claim 46
Independent Claim
123 words
A method of analyzing a sample, comprising the steps of: (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.
Claim 47
Independent Claim
123 words
A method of analyzing a sample, comprising the steps of: (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.
Claim 48
Dependent Claim
52 words
A method of analyzing a sample as claimed in claim 41, further comprising a first step of initiating a chemical reaction in said volume element of said sample, and wherein in steps (c) and (d) thereof, an initial rate of change of attenuation is measured and an initial concentration is determined, respectively.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-06-09 | 1995-12-09 | 1996-06-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-06-09 | 1999-12-09 | 2000-06-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-06-09 | 2003-12-09 | 2004-06-09 | $7700.00 | Window Closed / Lapsed |