AT325870B - DEVICE FOR CONTACT-FREE MEASUREMENT OF THE HUMIDITY CONTENT OF MOVING WEBS MADE OF DIELECTRIC MATERIAL, IN PARTICULAR OF PAPER WEBS - Google Patents
DEVICE FOR CONTACT-FREE MEASUREMENT OF THE HUMIDITY CONTENT OF MOVING WEBS MADE OF DIELECTRIC MATERIAL, IN PARTICULAR OF PAPER WEBSInfo
- Publication number
- AT325870B AT325870B AT533670A AT533670A AT325870B AT 325870 B AT325870 B AT 325870B AT 533670 A AT533670 A AT 533670A AT 533670 A AT533670 A AT 533670A AT 325870 B AT325870 B AT 325870B
- Authority
- AT
- Austria
- Prior art keywords
- contact
- dielectric material
- webs
- humidity content
- free measurement
- Prior art date
Links
- 239000003989 dielectric material Substances 0.000 title description 2
- 238000005259 measurement Methods 0.000 title description 2
- 239000003990 capacitor Substances 0.000 description 2
- 238000012935 Averaging Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- 238000001845 vibrational spectrum Methods 0.000 description 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
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)
Description
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geerdet ist, wird vorteilhaft auf die Frequenz der energiereichsten Schwingungen, die in dem Schwingungsspektrum des bei dem Übergang der Ladungen zwischen Bahn und Walze entstehenden elektromagnetischen Feldes auftreten, und der Schwingkreis--12, 13--des Verstärkers--4-auf dieselbe Frequenz abgestimmt. Der Verstärker--4--wirkt dann als Resonanzverstärker für die mit dem Resonanzkreis --3-- ausgesonderten Schwingungen, womit eine grosse Empfindlichkeit der Vorrichtung erzielbar ist.
Eine Spannungsquelle--8--ist über den Resonanzkreis--12, 13--an die Anode der Röhre--11--gelegt und
EMI2.1
dem Potentiometer --15-- und Erde liegt ein weiterer Kondensator-17-. Die Widerstände-14, 15- bzw. Kondensatoren--16, 17--bilden einen zwei RC-Glieder enthaltenden Integratorkreis--6--, dessen an dem Potentiometerkontakt abgegriffene Ausgangsspannung dem Gitter der Voltmeterröhre zugeführt ist.
Der Integratorkreis--6--, der nur ein RC-Glied zu enthalten brauchte, aber auch mehr als zwei RC-Glieder aufweisen könnte, bewirkt eine zeitliche Mittelwertbildung der gleichgerichteten Ausgangssignale des Resonanzverstärkers--4--und liefert ein etwa der Amplitudenmodulation dieses Ausgangssignales entsprechendes Mittelwertsignal, das an das Gitter der Röhre--18--gelangt. Im Gleichtakt mit diesem langsamer schwankenden, niederfrequenten Signal ändert sich der durch das Messinstrument--20--fliessende Strom, das deshalb mit einer gewissen Trägheit behaftet sein kann. Die auf einen Mittelwert basierte Information über den Feuchtigkeitsgehalt wird im übrigen den Forderungen der Praxis in vielen Fällen besser gerecht als eine die Feuchtigkeitsverteilung in Bahnlängsrichtung genau wiedergebene Information.
Erfindungsgemässe Vorrichtungen haben sich in der Praxis als zuverlässig und zur Messung des Feuchtigkeitsgehaltes mit einer allen Ansprüchen genügenden Genauigkeit brauchbar erwiesen und sind zufolge ihres einfachen Aufbaues aus handelsüblichen Schaltungsbestandteilen auch nicht teuer.
PATENTANSPRÜCHE :
1. Vorrichtung zum kontaktfreien Messen des Feuchtigkeitsgehaltes von bewegten Bahnen aus dielektrischem Material, insbesondere von Papierbahnen, mit einem im Abstand von der Bahn isoliert gehalterten Fühler, der an einen ein Anzeigegerät enthaltenden Messkreis angeschlossen ist, d a d u r c h g e k e n n- zeichnet, dass der Fühler als in der Nähe einer die Bahn (1) abstützenden, geerdeten Umlenkwalze od. dgl. angeordnete, in einem das Auftreten von Sprühentladungen ausschliessenden Abstand von der Bahn befindliche oder oberflächenisolierte Antenne (2) ausgebildet, diese an einen Schwingkreis (4) gekoppelt und an den Schwingkreis der Messkreis (7) angeschlossen ist.
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is grounded, it is advantageous to use the frequency of the most energetic vibrations that occur in the vibration spectrum of the electromagnetic field generated when the charges transfer between web and roller, and the oscillating circuit - 12, 13 - of the amplifier - 4 - to the same frequency Voted. The amplifier - 4 - then acts as a resonance amplifier for the vibrations separated out with the resonance circuit --3 -, with which a great sensitivity of the device can be achieved.
A voltage source - 8 - is applied via the resonance circuit - 12, 13 - to the anode of the tube - 11 - and
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The potentiometer -15- and earth is another capacitor -17-. The resistors -14, 15- or capacitors -16, 17-form an integrator circuit -6- containing two RC elements, the output voltage of which is tapped at the potentiometer contact and is fed to the grid of the voltmeter tube.
The integrator circuit - 6 - which only needed to contain one RC element, but could also have more than two RC elements, creates a temporal averaging of the rectified output signals of the resonance amplifier - 4 - and provides approximately the amplitude modulation of this Output signal corresponding to the mean value signal, which reaches the grid of the tube - 18 -. In synchronism with this slower fluctuating, low-frequency signal, the current flowing through the measuring instrument changes, which can therefore be subject to a certain inertia. The information about the moisture content based on an average value moreover meets the requirements of practice in many cases better than information which precisely reproduces the moisture distribution in the longitudinal direction of the web.
Devices according to the invention have proven in practice to be reliable and useful for measuring the moisture content with an accuracy that satisfies all requirements and, due to their simple construction from commercially available circuit components, are also not expensive.
PATENT CLAIMS:
1. Device for non-contact measurement of the moisture content of moving webs made of dielectric material, in particular paper webs, with a sensor which is held insulated at a distance from the web and is connected to a measuring circuit containing a display device, characterized in that the sensor as in the vicinity of a grounded deflecting roller or the like that supports the web (1) and is located at a distance from the web or surface-insulated antenna (2) that prevents the occurrence of spray discharges; the measuring circuit (7) is connected.
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Claims (1)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT533670A AT325870B (en) | 1970-06-12 | 1970-06-12 | DEVICE FOR CONTACT-FREE MEASUREMENT OF THE HUMIDITY CONTENT OF MOVING WEBS MADE OF DIELECTRIC MATERIAL, IN PARTICULAR OF PAPER WEBS |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT533670A AT325870B (en) | 1970-06-12 | 1970-06-12 | DEVICE FOR CONTACT-FREE MEASUREMENT OF THE HUMIDITY CONTENT OF MOVING WEBS MADE OF DIELECTRIC MATERIAL, IN PARTICULAR OF PAPER WEBS |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| ATA533670A ATA533670A (en) | 1975-01-15 |
| AT325870B true AT325870B (en) | 1975-11-10 |
Family
ID=3574665
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AT533670A AT325870B (en) | 1970-06-12 | 1970-06-12 | DEVICE FOR CONTACT-FREE MEASUREMENT OF THE HUMIDITY CONTENT OF MOVING WEBS MADE OF DIELECTRIC MATERIAL, IN PARTICULAR OF PAPER WEBS |
Country Status (1)
| Country | Link |
|---|---|
| AT (1) | AT325870B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0344554A3 (en) * | 1988-05-28 | 1990-12-19 | BASF Aktiengesellschaft | Measurement equipment for the determination of liquid-absorption by paper |
-
1970
- 1970-06-12 AT AT533670A patent/AT325870B/en not_active IP Right Cessation
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0344554A3 (en) * | 1988-05-28 | 1990-12-19 | BASF Aktiengesellschaft | Measurement equipment for the determination of liquid-absorption by paper |
Also Published As
| Publication number | Publication date |
|---|---|
| ATA533670A (en) | 1975-01-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| ELJ | Ceased due to non-payment of the annual fee |