GB622470A - Improvements in or relating to electric measuring instruments for measuring the moisture content of materials - Google Patents
Improvements in or relating to electric measuring instruments for measuring the moisture content of materialsInfo
- Publication number
- GB622470A GB622470A GB1169746A GB1169746A GB622470A GB 622470 A GB622470 A GB 622470A GB 1169746 A GB1169746 A GB 1169746A GB 1169746 A GB1169746 A GB 1169746A GB 622470 A GB622470 A GB 622470A
- Authority
- GB
- United Kingdom
- Prior art keywords
- condenser
- test
- moisture content
- balance
- bridge
- 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
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
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Abstract
622,470. Capacitance measurement. MARCONI INSTRUMENTS, Ltd., BROCKELSBY, C. F., and TODD, W. A. H. April 16, 1946, No. 11697. [Class 37] In an apparatus which measures moisture content of tobacco, wool, &c., the bulk density D of the test material need not be standardized. The invention is based on the relation k= a+bD, wherein k is dielectric constant, a is a constant and b depends on the moisture content and test frequency. Fig. 2 shows a bridge arrangement which measures the moisture content of tobacco for which material a=1. In Fig. 2, the ratio arms each comprise a fixed condenser shunted by a resistor (7, 9 and 8, 10) and the variable arms respectively, the test condenser 1, 2 in parallel with a condenser 12 and a variable condenser 6 (corresponds to bd) in parallel with a condenser 11. At balance prior to test, i.e. with condenser 1, 2 empty of test material the respective capacities of the condenser 6, set to its minimum value, and the condenser 12 are equal and the capacity of condenser 11 equals that of the test condenser 1, 2 empty (C o ). The test material is inserted in the test condenser 1, 2 and switch 13 placed in position 14 to apply high frequency f H to the bridge from oscillator 4 ; test condenser 1, 2 now possesses capacity K H Co, therefore the bridge is off balance as indicated by meter 24. Condenser 6 is varied to restore balance and the switch 13 thrown over to position 15 to apply low frequency f L from a variable tapping on potentiometer resistance 16 connected across oscillator 4. Test condenser 1, 2 now possesses capacity K L Co and the bridge is again off balance. In this case condenser 6 is undisturbed and the balance restored by varying the position of the potentiometer tapping. Potentiometer 16 is scaled in terms of moisture content and the position of the tapping indicates directly the amount of moisture present in the tobacco under test. Mathematical proof that potentiometer 16 may be so scaled is given in the Specification. The bridge output is taken through condenser 17, 18 and rectified by diodes 19, 20; coupled to meter 24 through resistances 21, 22.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1169746A GB622470A (en) | 1946-04-16 | 1946-04-16 | Improvements in or relating to electric measuring instruments for measuring the moisture content of materials |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1169746A GB622470A (en) | 1946-04-16 | 1946-04-16 | Improvements in or relating to electric measuring instruments for measuring the moisture content of materials |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB622470A true GB622470A (en) | 1949-05-03 |
Family
ID=9991042
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1169746A Expired GB622470A (en) | 1946-04-16 | 1946-04-16 | Improvements in or relating to electric measuring instruments for measuring the moisture content of materials |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB622470A (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3155898A (en) * | 1960-07-11 | 1964-11-03 | Industrial Nucleonics Corp | Method and apparatus for measuring multiple properties of material by applying electric fields at multiple frequencies and combining detection signals |
| US3155899A (en) * | 1957-02-26 | 1964-11-03 | Industrial Nucleonics Corp | Method and apparatus for determining moisture content and other variables utilizing a capacitor test cell at two different frequencies |
| US3155902A (en) * | 1962-11-16 | 1964-11-03 | Industrial Nucleonics Corp | Method and apparatus for determining moisture content of dielectric materials by measuring the ratio of voltage changes at two frequencies |
| US3155900A (en) * | 1960-07-11 | 1964-11-03 | Industrial Nucleonics Corp | Measuring system for determining the mass of a dielectric material utilizing a capacitive probe at two frequencies |
| US3255410A (en) * | 1962-02-21 | 1966-06-07 | Industrial Nucleonics Corp | System and method for measuring a property of dielectric material by periodically and alternately applying signals at different frequencies to a capacitance probe and measuring the difference in output signals while maintaining the average amplitude of the output signals constant |
| US3255412A (en) * | 1962-02-24 | 1966-06-07 | Industrial Nucleonics Corp | System for measuring a property of a dielectric material by periodically applying signals at different frequencies to a capacitance probe |
| US3255411A (en) * | 1962-02-21 | 1966-06-07 | Industrial Nucleonics Corp | System and method for measuring a property of a dielectric material by applying signals at two different frequencies to a capacitance probe and measuring the difference in output signals while maintaining one output signal constant |
| US3320946A (en) * | 1962-07-30 | 1967-05-23 | Dethloff | Method and means for testing cellular tissues |
| US3323049A (en) * | 1965-12-07 | 1967-05-30 | Industrial Nucleonics Corp | System for quantitatively measuring a property of dielectric material by applying input signals at two different frequencies to a capacitance probe and varying the frequency of one input signal to maintain a constant ratio of output signals for the two frequencies |
| US3327207A (en) * | 1963-03-29 | 1967-06-20 | Industrial Nucleonics Corp | Two frequency system for measuring a property of a dielectric material having a single amplifying and detecting circuit for both frequencies |
-
1946
- 1946-04-16 GB GB1169746A patent/GB622470A/en not_active Expired
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3155899A (en) * | 1957-02-26 | 1964-11-03 | Industrial Nucleonics Corp | Method and apparatus for determining moisture content and other variables utilizing a capacitor test cell at two different frequencies |
| US3155898A (en) * | 1960-07-11 | 1964-11-03 | Industrial Nucleonics Corp | Method and apparatus for measuring multiple properties of material by applying electric fields at multiple frequencies and combining detection signals |
| US3155900A (en) * | 1960-07-11 | 1964-11-03 | Industrial Nucleonics Corp | Measuring system for determining the mass of a dielectric material utilizing a capacitive probe at two frequencies |
| US3255410A (en) * | 1962-02-21 | 1966-06-07 | Industrial Nucleonics Corp | System and method for measuring a property of dielectric material by periodically and alternately applying signals at different frequencies to a capacitance probe and measuring the difference in output signals while maintaining the average amplitude of the output signals constant |
| US3255411A (en) * | 1962-02-21 | 1966-06-07 | Industrial Nucleonics Corp | System and method for measuring a property of a dielectric material by applying signals at two different frequencies to a capacitance probe and measuring the difference in output signals while maintaining one output signal constant |
| US3255412A (en) * | 1962-02-24 | 1966-06-07 | Industrial Nucleonics Corp | System for measuring a property of a dielectric material by periodically applying signals at different frequencies to a capacitance probe |
| US3320946A (en) * | 1962-07-30 | 1967-05-23 | Dethloff | Method and means for testing cellular tissues |
| US3155902A (en) * | 1962-11-16 | 1964-11-03 | Industrial Nucleonics Corp | Method and apparatus for determining moisture content of dielectric materials by measuring the ratio of voltage changes at two frequencies |
| US3327207A (en) * | 1963-03-29 | 1967-06-20 | Industrial Nucleonics Corp | Two frequency system for measuring a property of a dielectric material having a single amplifying and detecting circuit for both frequencies |
| US3323049A (en) * | 1965-12-07 | 1967-05-30 | Industrial Nucleonics Corp | System for quantitatively measuring a property of dielectric material by applying input signals at two different frequencies to a capacitance probe and varying the frequency of one input signal to maintain a constant ratio of output signals for the two frequencies |
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