US4097743A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Moisture analyzing method and apparatus
Assignee: MOISTURE SYSTEMS CORP
•
Filing: 1977-04-19
•
Granted: 1978-06-27
•
Expires: 1997-04-19
Abstract
Abstract A moisture analyzer including a first optical system for receiving radiant energy from a source and producing therewith first and second radiant energy beams having a given band of wavelength readily absorbable by moisture and a second optical system for receiving energy from the source and producing therewith third and fourth radiant energy beams having a common band of wavelength less readily absorbable by moisture. An optical director system directs the first and third beams to a sample being analyzed and then to a photodetector and directs the second and fourth beams directly to the photodetector without contacting the sample. In response to the output of the photodetector, an output circuit produces an electrical signal dependent upon a relationship ##EQU1## WHERE V m is a signal value dependent upon the detected energy level of the first beam, V m' is a signal value dependent upon the detected energy level of the second beam, V r is a signal value dependent upon the detected energy level of the third beam and V r' is a signal value dependent upon the detected energy level of the fourth beam. The term Vr/Vm is a ratio of the different levels of energy absorbed by moisture from the first and third beams of different wavelength and therefore is a measurement of the moisture content in the sample. Conversely, the second and fourth beams that produce the signal V m' and V r' are not affected by moisture content of the sample. They are influenced, however, by any temperature induced optical transmission changes in exactly the same manner as are the first and third beams that produce the signals V r and V m . Thus, any inaccuracies that would result from such transmission changes are canceled from the moisture indicating output signal ##EQU2##
Inventors
- 👤 Roger E. Carlson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 00:40
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/314
Claims Analysis
Total Claims: 45
Claim 1
Independent Claim
116 words
Analyzer apparatus comprising: radiant energy source means; first optical means for receiving radiant energy from said source means and producing first and second radiant energy beams having the same given band of wavelength; second optical means for receiving radiant energy from said source means and producing third and fourth radiant energy beams having a common band of wavelength different than said given band; photodetector means; radiant energy director means for directing said first and third beams first to a sample being analyzed and then to said photodetector means and directing said second and fourth beams to said photodetector means; and output means for comparing the energy levels of said beams as detected by said photodetector means.
Claim 2
Dependent Claim
116 words
Analyzer apparatus comprising: radiant energy source means; first optical means for receiving radiant energy from said source means and producing first and second radiant energy beams having the same given band of wavelength; second optical means for receiving radiant energy from said source means and producing third and fourth radiant energy beams having a common band of wavelength different than said given band; photodetector means; radiant energy director means for directing said first and third beams first to a sample being analyzed and then to said photodetector means and directing said second and fourth beams to said photodetector means; and output means for comparing the energy levels of said beams as detected by said photodetector means.
Claim 3
Dependent Claim
81 words
Apparatus according to claim 1 wherein said photodetector means produces a signal V m dependent upon the energy level of said first beam, a signal V r' dependent upon the energy level of said third beam, a signal V m' dependent upon the energy level of said second beam, and a signal V r dependent upon the energy level of said fourth beam, and said output means comprises signal processor means for producing an output signal dependent upon the relationship ##EQU10##
Claim 4
Dependent Claim
25 words
Apparatus according to claim 2 wherein said first optical means comprises a first optical filter, and said second optical means comprises a second optical filter.
Claim 5
Dependent Claim
91 words
Apparatus according to claim 3 wherein said first and second optical means comprise collimator means for receiving energy from said source means and producing therewith a measure radiant energy beam and a compensating radiant energy beam, and motive means for moving said first optical filter alternately into said measure beam to produce said first beam and into said compensating beam to produce said second beam, and moving said second optical filter alternately into said measure beam to produce said third beam and into said compensating beam to produce said fourth beam.
Claim 6
Dependent Claim
20 words
Apparatus according to claim 4 wherein said motive means comprises a rotary wheel supporting said first and second optical filters.
Claim 7
Dependent Claim
28 words
Apparatus according to claim 5 wherein said collimator means comprises accumulator means for providing a higher radiant energy level in said measure beam than in said compensating beam.
Claim 8
Dependent Claim
22 words
Apparatus according to claim 5 including adjustable energy attenuation means for adjusting the radiant energy levels of said second and fourth beams.
Claim 9
Dependent Claim
48 words
Apparatus according to claim 5 wherein said first and second filters are mounted on said rotary wheel in positions equally spaced from its center of rotation, and said measure and compensating beams are sized and oriented to pass through equally sized portions of said first and second filters.
Claim 10
Dependent Claim
22 words
Apparatus according to claim 8 wherein said measure and compensating beams are focused upon substantially diametrically opposed locations on said rotary wheel.
Claim 11
Dependent Claim
25 words
Apparatus according to claim 9 wherein said first and second filters are mounted on said rotary wheel in positions angularly spaced apart by between 50°-130°.
Claim 12
Dependent Claim
58 words
Apparatus according to claim 5 wherein said photodetector means comprises a photodetector that sequentially receives said first, second, third and fourth beams and produces an ac signal with values determined by the energy levels thereof; and including decoder means for identifying the portions of said ac signal determined by each of said first, second, third and fourth beams.
Claim 13
Dependent Claim
34 words
Apparatus according to claim 11 including commutator means for producing timing pulses received by said decoder means and indicating periods of coincidence between said first and second filters and said measure and compensating beams.
Claim 14
Dependent Claim
45 words
Apparatus according to claim 12 wherein said commutator means comprise a commutator radiant energy source associated with each of said first and second filters and movable with said rotary wheel, and commutator energy detector means energized by said commutator sources in certain angular positions thereof.
Claim 15
Dependent Claim
29 words
Apparatus according to claim 12 wherein said commutator means comprises initiator means for producing periodic pulses received by said decoder means and identifying the sequence of said timing pulses.
Claim 16
Dependent Claim
45 words
Apparatus according to claim 14 wherein said commutator means comprise a commutator radiant energy source associated with each of said first and second filters and movable with said rotary wheel, and commutator energy detector means energized by said commutator sources in certain angular positions thereof.
Claim 17
Dependent Claim
35 words
Apparatus according to claim 15 wherein said initiator means comprises initiator radiant energy source means movable with said rotary wheel and energizing said commutator detector means distinguishably from said energization thereof by said commutator sources.
Claim 18
Dependent Claim
25 words
Apparatus according to claim 16 including reset means activated by said periodic pulses by said initiator means to periodically ground the output of said photodetector.
Claim 19
Dependent Claim
30 words
Apparatus according to claim 2 including reset means for periodically grounding the output of said photodetector means so as to establish a base dc level for measurement of said signals.
Claim 20
Dependent Claim
102 words
Apparatus according to claim 2 wherein said signal processor means comprises log converter means for producing log signals proportional to log values of said signals, V r , V r' , V m and V m' ; summing means for producing a composite log signal having a value proportional to the sum of said log values of said signals V r and V m' less the sum of said log values of said signals V r' and V m ; and antilog converter means for producing an analog output signal having a value proportional to an antilog value of said composite signal.
Claim 21
Dependent Claim
106 words
Apparatus according to claim 19 wherein said log converter means comprise first, second, third and fourth transistors; circuit means for producing collector currents proportional to V r in said first transistor, to V m in said second transistor, to V r' in said third transistor, and to V m' in said fourth transistor; circuit means for combining the base-emitter voltages of said transistors to produce said composite signal; an antilog transistor; and circuit means producing for said antilog transistor a base-emitter voltage proportional to the value of said composite signal and a collector current having a value proportional to the value of said analog output signal.
Claim 22
Dependent Claim
25 words
Apparatus according to claim 20 wherein said first optical means comprises a first optical filter, and said second optical means comprises a second optical filter.
Claim 23
Dependent Claim
91 words
Apparatus according to claim 21 wherein said first and second optical means comprise collimator means for receiving energy from said source means and producing therewith a measure radiant energy beam and a compensating radiant energy beam, and motive means for moving said first optical filter alternately into said measure beam to produce said first beam and into said compensating beam to produce said second beam, and moving said second optical filter alternately into said measure beam to produce said third beam and into said compensating beam to produce said fourth beam.
Claim 24
Dependent Claim
20 words
Apparatus according to claim 22 wherein said motive means comprises a rotary wheel supporting said first and second optical filters.
Claim 25
Dependent Claim
59 words
Apparatus according to claim 23 wherein said photodetector means comprises a photodetector that sequentially receives said first, second, third and fourth beams and produces an ac signal with values determined by the energy levels thereof; and including a decoder means for identifying the portions of said ac signal determined by each of said first, second, third and fourth beams.
Claim 26
Dependent Claim
34 words
Apparatus according to claim 24 including commutator means for producing timing pulses received by said decoder means and indicating periods of coincidence between said first and second filters and said measure and compensating beams.
Claim 27
Dependent Claim
26 words
Apparatus according to claim 2 wherein said photodetector means is positioned so as to receive said first and third beams after reflection thereof from the sample.
Claim 28
Dependent Claim
27 words
Apparatus according to claim 13 wherein said commutator sources comprise reflective surfaces on said rotary wheel and a light source for directing light toward said reflective surfaces.
Claim 29
Dependent Claim
35 words
Apparatus according to claim 2 wherein said first and second beams have a narrow bandwidth centered at approximately 1.9 microns and said third and fourth beams have a narrow bandwidth centered at approximately 1.8 microns.
Claim 30
Dependent Claim
131 words
Analyzer apparatus comprising: radiant energy source means; first optical means for receiving radiant energy from said source means and producing a measure beam of radiant energy; second optical means for receiving radiant energy from said source means and producing a reference beam of radiant energy; a photodetector having a variable resistance dependent upon the level of radiant energy received; radiant energy director means for directing said measure and reference beams first to a sample being analyzed and then to said photodetector; power supply means establishing a voltage across said photodetector; a balanced differential input circuit receiving said voltage across said photodetector; and output means for receiving the variable output of said differential input circuit and producing an output signal representing the difference in energy levels between said measure and reference beams.
Claim 31
Dependent Claim
131 words
Analyzer apparatus comprising: radiant energy source means; first optical means for receiving radiant energy from said source means and producing a measure beam of radiant energy; second optical means for receiving radiant energy from said source means and producing a reference beam of radiant energy; a photodetector having a variable resistance dependent upon the level of radiant energy received; radiant energy director means for directing said measure and reference beams first to a sample being analyzed and then to said photodetector; power supply means establishing a voltage across said photodetector; a balanced differential input circuit receiving said voltage across said photodetector; and output means for receiving the variable output of said differential input circuit and producing an output signal representing the difference in energy levels between said measure and reference beams.
Claim 32
Dependent Claim
42 words
Apparatus according to claim 29 wherein said balanced differential input circuit comprises an operational amplifier having inputs connected to output terminals of said photodetector and said power supply comprises equal and opposite voltage supplies, one connected to each of said output terminals.
Claim 33
Dependent Claim
53 words
Apparatus according to claim 30 wherein said input circuit further comprises a load resistor connected between each of said voltage supplies and one of said output terminals and a pair of coupling capacitors one connected between each of said inputs of said operational amplifier and one of said output terminals of said photodetector.
Claim 34
Dependent Claim
149 words
Analyzer apparatus comprising: radiant energy source means; first optical means for receiving radiant energy from said source means and producing a measure beam of radiant energy; second optical means for receiving radiant energy from said source means and producing a reference beam of radiant energy; photodetector means; radiant energy director means for directing said measure and reference beams first to a sample being analyzed and resultant reflected energy to said photodetector means; a housing retaining said energy director means and said photodetector means, said housing comprising a flat window for first transmitting said beam to the sample and then transmitting said reflected energy to said photodetector means and optical shield means for shielding said photodetector means from radiant energy reflected by said window incident to said transmission of said beams to the sample; output means for comparing the energy levels of said beams as detected by said photodetector means.
Claim 35
Dependent Claim
149 words
Analyzer apparatus comprising: radiant energy source means; first optical means for receiving radiant energy from said source means and producing a measure beam of radiant energy; second optical means for receiving radiant energy from said source means and producing a reference beam of radiant energy; photodetector means; radiant energy director means for directing said measure and reference beams first to a sample being analyzed and resultant reflected energy to said photodetector means; a housing retaining said energy director means and said photodetector means, said housing comprising a flat window for first transmitting said beam to the sample and then transmitting said reflected energy to said photodetector means and optical shield means for shielding said photodetector means from radiant energy reflected by said window incident to said transmission of said beams to the sample; output means for comparing the energy levels of said beams as detected by said photodetector means.
Claim 36
Dependent Claim
78 words
Apparatus according to claim 32 wherein said optical shield means comprises an optically dense tube retained by said housing and enclosing said beams, said tube defining a volume optically shielded from said photodetector means and an opening for transmitting said beams to the sample, and wherein said opening is directly adjacent to a given area of said window such that all radiant energy reflected by said window incident to transmission of said beams is received by said volume.
Claim 37
Dependent Claim
29 words
Apparatus according to claim 33 wherein said window includes an annular portion around said given area, and said reflected energy from the sample is transmitted by said annular portion.
Claim 38
Dependent Claim
132 words
Analyzer apparatus comprising: radiant energy source means; first optical means for receiving radiant energy from said source means and producing a measure beam of radiant energy; second optical means for receiving radiant energy from said source means and producing a reference beam of radiant energy; photodetector means; radiant energy director means for directing said measure and reference beams first to a sample being analyzed and then to said photodetector means; processing circuit means responsive to said photodetector means and producing an output signal indicative of the relative energy levels of said measure and reference beams received by said photodetector means; and fault detector means for monitoring voltage levels in said processing circuit means and producing a fault indication in response to the occurrence of voltage levels above or below a given range.
Claim 39
Dependent Claim
132 words
Analyzer apparatus comprising: radiant energy source means; first optical means for receiving radiant energy from said source means and producing a measure beam of radiant energy; second optical means for receiving radiant energy from said source means and producing a reference beam of radiant energy; photodetector means; radiant energy director means for directing said measure and reference beams first to a sample being analyzed and then to said photodetector means; processing circuit means responsive to said photodetector means and producing an output signal indicative of the relative energy levels of said measure and reference beams received by said photodetector means; and fault detector means for monitoring voltage levels in said processing circuit means and producing a fault indication in response to the occurrence of voltage levels above or below a given range.
Claim 40
Dependent Claim
42 words
Apparatus according to claim 35 wherein said detector means comprises a plurality of fault detectors each monitoring a different voltage in said processing circuit means and producing a distinguishable fault indication in response to fluctuations of said different voltages beyond predetermined ranges.
Claim 41
Dependent Claim
42 words
Apparatus according to claim 36 wherein each of said plurality of fault detectors comprises a dual level detector circuit for receiving said different voltage, and a signal light energized in response to detection of said fluctuations by said dual level detector circuit.
Claim 42
Independent Claim
88 words
A method for analyzing the composition of a sample and including the steps of: producing first and second radiant energy beams having the same given band of wavelength; producing third and fourth radiant energy beams having a common band of wavelength different than said given band; directing said first and third beams to the sample being analyzed; determining the resultant energy level ratio of said first and third beams; and compensating said resultant energy level ratio with a comparison energy level ratio of said second and fourth beams.
Claim 43
Independent Claim
88 words
A method for analyzing the composition of a sample and including the steps of: producing first and second radiant energy beams having the same given band of wavelength; producing third and fourth radiant energy beams having a common band of wavelength different than said given band; directing said first and third beams to the sample being analyzed; determining the resultant energy level ratio of said first and third beams; and compensating said resultant energy level ratio with a comparison energy level ratio of said second and fourth beams.
Claim 44
Dependent Claim
77 words
A method according to claim 38 wherein said producing steps comprise the steps of: producing a measure radiant energy beam; producing a compensating radiant energy beam; sequentially passing said measure beam through a first optical filter to produce said first beam and through a second optical filter to produce said third beam; sequentially passing said compensating beam through said first filter to produce said second beam and through said second optical filter to produce said fourth beam.
Claim 45
Dependent Claim
52 words
A method according to claim 39 wherein said compensating step comprises reducing the energy level of said first beam by an amount proportional to the energy level of said second beam and reducing the energy level of said third beam by an amount proportional to the energy level of said fourth beam.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-06-26 | 1981-12-26 | 1982-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-26 | 1985-12-26 | 1986-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-26 | 1989-12-26 | 1990-06-27 | $7700.00 | Window Closed / Lapsed |