Measuring and testing – Gas analysis – By vibration
Reexamination Certificate
1998-12-30
2002-06-04
Williams, Hezron (Department: 2856)
Measuring and testing
Gas analysis
By vibration
C073S030040, C073S030030, C073S031050, C073S03200R, C073S054260, C073S061790, C073S064530, C324S207130
Reexamination Certificate
active
06397661
ABSTRACT:
BACKGROUND OF THE INVENTION
In general, the present invention relates to chemical telemetry using chemical sensing devices remotely located from associated pick-up and processing units for the sensing and monitoring of analytes, fluid properties such as viscosity and density, and temperature. More particularly, the invention relates to a novel remote analyte sensing apparatus, temperature sensing apparatus, and viscosity sensing apparatus, and associated new methods of sensing temperature of an environment, sensing viscosity, and sensing the presence, concentration, or absence of chemical elements and compounds (whether useful or unwanted/contaminating and in any of various states: liquid, gas, plasma, and solid), pH levels, germs (bacteria, virus, etc.), enzymes, antibodies, and so on in a number of environments such as biomedical applications (whether in vivo or in vitro), within medical test samples, food quality/inspection (whether measuring moisture within sealed packing or outside of packaging), monitoring of heavy metals found in water (groundwater, treated water, or wastewater flowing in natural waterways, canals, or pipes), and monitoring of solid or gas manufacturing waste, etc. The new sensing apparatus and method(s) provide information about an analyte and environment utilizing magneto-elastic emissions of a sensor, or several sensor structures.
Known chemical sensing technologies generally require the operation of complex, specifically tailored sensing units, electrically connected, to monitor a target analyte. For example, Groger et al. has a
FIG. 4
with a chemically sensitive film
93
positioned between coils
92
and
94
(each of which has been wrapped around a ferrite core); a
FIG. 5
with eddy current probes
21
formed by chemical deposition or chemically etching a copper clad printed circuit board (PCB) substrate
11
of a conductive polymer film of polypyrrole, polythiophene or polyaniline which may be deposited directly onto the inductor array or separated by spacers; and a
FIG. 6
showing a spiral-wound inductor eddy current probe
13
with a thick film ferrite core
42
deposited on (or etched on) a PCB substrate
12
. The Groger et al. probe design is incorporated into an instrument that has a digital signal processor (DDS ) circuit.
FIG. 9
illustrates that the probe
83
(such as that in
FIG. 3
or
6
) is in electrical connection with, and driven by, sinewave generator
80
, preferably a direct digital signal generator, and an op amp
85
to produce a waveform output
86
.
Kaiser illustrates a sensor
12
, measurement circuit
10
and responder unit
16
coupled to a PCB
22
as an integrated circuit
24
(see
FIGS. 1
,
2
A, and
2
B), all contained in a housing
18
. The integrated circuit
24
(
FIG. 2A
) is electrically connected to a sensor electrode
20
and reference electrode
21
: The potential difference that develops between the electrodes
20
and
21
in relation to ion concentration, is measured to provide a pH level reading. In
FIG. 2B
, the sensor
12
of integrated circuit assembly
24
is a temperature sensor which is completely sealed within housing
18
.
FIGS. 3
,
4
, and
5
illustrate measurement circuit
10
embodiments: In
3
and
4
, a voltage follower
44
outputs a signal proportional to the potential difference detected at sensor
12
;
FIG. 5
illustrates a familiar Wheatstone bridge with an AC generator
200
powered by an interrogation signal sent by interrogation unit
14
. In operation (FIGS.
1
and
6
), the RF transmitting and receiving circuitry
64
of interrogation unit
14
, transmits an inquiry signal. Sometime thereafter, upon detecting its proper responder unit address, the responder unit
16
transmits data from the measurement circuit
10
back to interrogation unit circuitry
64
.
Lewis et al. describes an analog of the mammalian olfactory system (i.e., electronic-nose) having chemiresistor elements micro-fabricated onto a micro-chip. Each sensor has at least first and second conductive leads electrically coupled to and separated by a chemically sensitive resistor (FIG.
4
A-
1
). Each resistor has a plurality of alternating nonconductive and conductive regions transverse to the electrical path between the conductive leads. The chemiresistors are fabricated by blending a conductive material with a nonconductive organic polymer such that the electrically conductive path between the leads coupled to the resistor is interrupted by gaps of non-conductive organic polymer material. See, column 3, lines 38-50. Lewis et al. describes this as “electronic noses, for detecting the presence of an analyte in a fluid” (col. 8). An electronic smelling system according to Lewis et al. (col. 7) has sensor arrays in electrical communication with a measuring device for detecting resistance across each chemiresistor, a computer, a data structure of sensor array response profiles, and a comparison algorithm.
One of the applicants hereof, in conjunction with another, developed a magneto-chemical sensor comprised of a thin polymeric spacer layer made so that it swells in the presence of certain stimuli, bounded on each side by a magnetically soft thin film, as described in an article co-authored by the applicant entitled A Remotely Interrogatable Magnetochemical pH Sensor, IEEE Transactions on Magnetics, Vol. 33, No. 5, September 1997. When placed within a sinusoidal magnetic field the sensor generates a series of voltage spikes in suitably located detecting coils. The magnetic switching characteristics of the sensor are dependent upon the thickness of the sandwiched intervening polymeric spacer layer. The sandwiched “chemical transduction element” of this magnetism-based technology was made of a lightly crosslinked polymer designed to swell or shrink with changes in the concentration of the species to be sensed. The magnitude of each of the voltage spikes generated by the sensor is dependent upon how much the sandwiched spacer layer has swollen in response to the given stimuli. This sensor can be used with interrogation and detection electronics commonly used in magnetic anti-theft identification marker systems.
In a subsequent structurally-modified magnetochemical sensor developed by the applicants hereof, with others (A Remotely Interrogatable Sensor for Chemical Monitoring, IEEE Transactions on Magnetics, Vol. 34, No.4, July 1998), a thin film single or array of magnetostatically coupled magnetically soft ferromagnetic thin film structure(s) is adhered to a thin polymeric layer made so that it swells or shrinks in response to a chemical analyte. The sensor is placed within a sinusoidal magnetic field and the magnetization vector of the magnetically soft coupled sensor structures periodically reverses direction generating a magnetic flux that can be remotely detected as a series of voltage spikes in pick-up coils. The four-square array is of magnetically soft thin structures bonded to a polymeric base-substrate layer with acrylate acetate (SUPERGLUE®) and baked. When the swellable base swells (low pH): the distance between the square magnetically soft structures enlarges resulting in less coupling between these structures. If immersed in high pH: this base shrinks as does the distance between structures resulting in a larger voltage signal.
Anderson, III et al. discloses a marker
16
(
FIG. 5
) formed of a strip
18
of a magnetostrictive, ferromagnetic material adapted, when armed in its activated mode, to resonate mechanically at a frequency within the range of the incident magnetic field. A hard ferromagnetic element
44
disposed adjacent to the strip
18
is adapted, upon being magnetized, to magnetically bias the strip
18
and thereby arm it to resonate at that frequency. An oscillator provides an AC magnetic field within interrogation zone
12
to mechanically resonate a magnetostrictive strip
18
, which has first been armed by a magnetized hard ferromagnetic element
44
, upon exposure to this AC magnetic field. The sole object of Anderson, III et al. EAS marker is to detect the presence between coi
Grimes Craig A.
Stoyanov Plamen G.
Macheledt Bales LLP
Miller Rose M.
University of Kentucky Research Foundation
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