GB1192748A - Method and Apparatus for Measuring a Property of Dielectric Material - Google Patents
Method and Apparatus for Measuring a Property of Dielectric MaterialInfo
- Publication number
- GB1192748A GB1192748A GB3139367A GB3139367A GB1192748A GB 1192748 A GB1192748 A GB 1192748A GB 3139367 A GB3139367 A GB 3139367A GB 3139367 A GB3139367 A GB 3139367A GB 1192748 A GB1192748 A GB 1192748A
- Authority
- GB
- United Kingdom
- Prior art keywords
- phase
- frequency
- moisture content
- signals
- measuring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000003989 dielectric material Substances 0.000 title abstract 2
- 239000000523 sample Substances 0.000 abstract 4
- 239000013078 crystal Substances 0.000 abstract 1
- 239000000463 material Substances 0.000 abstract 1
- 238000005259 measurement Methods 0.000 abstract 1
- 230000010363 phase shift Effects 0.000 abstract 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/22—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance
- G01N27/223—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance for determining moisture content, e.g. humidity
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
Landscapes
- Power Engineering (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- General Physics & Mathematics (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Electrochemistry (AREA)
- Analytical Chemistry (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Ceramic Engineering (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Computer Hardware Design (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
- Paper (AREA)
Abstract
1,192,748. Measuring moisture content; measuring dielectric constant. INDUSTRIAL NUCLEONICS CORP. July 7, 1967 [July 7, 1966(2)], No.31393/67. Headings G1N and G1U. A property of a dielectric material, e.g. the moisture content of a paper web, is measured by subjecting the material to an alternating voltage, measuring the phase of the current with respect to the applied voltage, controlling the frequency of the applied voltage in such a way as to maintain the phase at a predetermined value, and indicating the value of the property (moisture content) as a function of the frequency. In one arrangement, Fig. 2, the phase is measured by two phase-sensitive demodulators (74, 76), indicated schematically by reference 48, receiving respective reference signals in phase and in quadrature with the applied voltage to produce respective D.C. signals of opposite polarity and of magnitudes indicative of the in phase and quadrature components of the current. These signals are summed in a resistance chain 56 and used to control a servomotor 62 to control the frequency of the generator. One of the D. C. signals is fed back to control the gain of an amplifier 38 supplying the alternating voltage to capacitive probe 12. A balance circuit 40, which is preferably a bridge circuit (114), Fig. 4 (not shown), is provided for balancing out the phase shift in the absence of the paper. Feedback through impedance 46 maintains point 42 at a constant potential. As described with reference to Fig. 6 (not shown), the resistance chain 56 comprises three potentiometers in series and a switch (146) for selecting a required one of the three outputs to determine the predetermined value (e.g. 25 degrees, 45 degrees, 75 degrees) at which the phase is maintained, as appropriate for the expected range of moisture content of the paper. As described with reference to Fig. 3 (not shown), the generator is a squarewave oscillator (78) of double the frequency applied to the probe and multivibrators (80, 82, 84) are used in known manner to derive the in phase and quadrature reference signals. The squarewave is converted into a sine wave Fig. 4 (not shown) before being applied to the probe. In another arrangement, Fig. 8, the markspace ratio of the output signal of multi-vibrator 140 is representative of the phase. The output from the multi-vibrator 140 is smoothed to a D.C. and compared with a D.C. reference voltage to provide an error signal for controlling the frequency of oscillator 26. Two oscillators are provided: a 10 Mc/s crystal controlled oscillator 24 and the oscillator 26 which has a frequency variable within the range 9 to 10 Mc/s whereby the output of mixer 28 is variable in frequency from 0 to 1 Mc/s. The frequency measurement may be converted in a function generator to give an output signal linearly related to moisture content. Alternatively, the function generator may be omitted and a non- linear, e.g. logarithmic, scale provided on the measuring instrument. Temperature compensation and selectable resistors to compensate for different grades of paper may be provided, Fig. 9 (not shown). The probe may be traversed across the web.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US56360966A | 1966-07-07 | 1966-07-07 | |
US56348766A | 1966-07-07 | 1966-07-07 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1192748A true GB1192748A (en) | 1970-05-20 |
Family
ID=27073305
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB3139367A Expired GB1192748A (en) | 1966-07-07 | 1967-07-07 | Method and Apparatus for Measuring a Property of Dielectric Material |
Country Status (2)
Country | Link |
---|---|
GB (1) | GB1192748A (en) |
SE (1) | SE337707B (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2007034519A1 (en) * | 2005-09-26 | 2007-03-29 | Giottoindustrial Networking S.A. | Method and apparatus for measuring capacity variations of a condenser |
GB2447477A (en) * | 2007-03-14 | 2008-09-17 | Univ Montfort | Measuring the dielectric properties of a conductive material |
-
1967
- 1967-06-30 SE SE995367A patent/SE337707B/xx unknown
- 1967-07-07 GB GB3139367A patent/GB1192748A/en not_active Expired
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2007034519A1 (en) * | 2005-09-26 | 2007-03-29 | Giottoindustrial Networking S.A. | Method and apparatus for measuring capacity variations of a condenser |
GB2447477A (en) * | 2007-03-14 | 2008-09-17 | Univ Montfort | Measuring the dielectric properties of a conductive material |
Also Published As
Publication number | Publication date |
---|---|
SE337707B (en) | 1971-08-16 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
PLNP | Patent lapsed through nonpayment of renewal fees |