DE2401811A1 - Flow velocity pickup for electrically insulating liquid - is capacitor consisting of insulating tube with two metal electrodes - Google Patents

Flow velocity pickup for electrically insulating liquid - is capacitor consisting of insulating tube with two metal electrodes

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Publication number
DE2401811A1
DE2401811A1 DE2401811A DE2401811A DE2401811A1 DE 2401811 A1 DE2401811 A1 DE 2401811A1 DE 2401811 A DE2401811 A DE 2401811A DE 2401811 A DE2401811 A DE 2401811A DE 2401811 A1 DE2401811 A1 DE 2401811A1
Authority
DE
Germany
Prior art keywords
voltage
coils
yokes
transducer
pole pieces
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.)
Ceased
Application number
DE2401811A
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German (de)
Inventor
Theo Fett
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Individual
Original Assignee
Individual
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to DE2401811A priority Critical patent/DE2401811A1/en
Publication of DE2401811A1 publication Critical patent/DE2401811A1/en
Ceased legal-status Critical Current

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Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01FMEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/56Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects
    • G01F1/64Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects by measuring electrical currents passing through the fluid flow; measuring electrical potential generated by the fluid flow, e.g. by electrochemical, contact or friction effects
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01PMEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P5/00Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
    • G01P5/08Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring variation of an electric variable directly affected by the flow, e.g. by using dynamo-electric effect

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Fluid Mechanics (AREA)
  • Measuring Volume Flow (AREA)

Abstract

Two pole pieces are placed at the sides of a rectangular tube and are connected by two transversal yokes carrying coils, with both coils connected in series; the capacitor displacement current and opposite direction currents in the leads flow through the magnetic circuit consisting of the pole pieces and yokes. Instead of the two coils a pair of magnetically sensitive indicators, such as Hall generators and field plates may be inserted into air gaps in the yokes. The H.F. voltage applied to the electrodes is modulated several times; it may be amplitude modulated twice. The pick up signal is amplified by a system consisting of selective amplifiers tuned to the modulation and H.F. carrier frequencies.

Description

Vorrichtung zur kapazitisen Durchflußmessung an Flüssigkeiten. Device for capacitive flow measurement on liquids.

In der Hauptanmeldung wird ein Verfahren beschrieben, bei dem die. Strömungsgeschwindigkeit elektrisch isolierender Fltselgkeiten erfaßt wird, indem die Flüssigkeit einen unter hochfrequenter Wechselspannung stehenden Kondensator durchstrbmt und die senkrecht zur elektrischen Feldstärke und der Strömungsrichtung stehende magnetische Feldstärke gemessen wird.In the main application, a method is described in which the. Flow rate of electrically insulating liquids is detected by the liquid a capacitor under high-frequency alternating voltage flow through and perpendicular to the electric field strength and the direction of flow standing magnetic field strength is measured.

Von Nachteil ist dabei, daß die auftretenden Meßeffekte nur klein sind und damit eine hohe Anfällxgkeit gegen Störsnannungen zeigen.The disadvantage here is that the measurement effects that occur are only small and thus show a high susceptibility to Störnannungen.

Erfindungsgemäß werden zur 3eseitigung dieses Nachteils zwei Verbesserungen angegeben: 1. Da die Meßeffekte kleiner als die Rauschspannungen der Verstärker sein können, empfiehlt es sich, die an Kondensator anliegende, durch eine Oszillatorschaltung erzeugte Hochfrequenz zu modulieren. Eine Mehrfache Amplitudenmodulation (z.B. Hochfrequenz 10 MHz, 1. Modulationsfrequenz 455 kHz, 2. Modulationsfrequenz 1no Hz getastet) ermöglicht durch die Verwendung mehrerer selektiver, auf die jeweilige Frequenz abgestimmter Verstärker eine ausreichende Unterdrückung der Rauschspannungen. Ein Blockschaltbild zeigt Fig.1. Die Wirkung der Modulation sei hier schematisch als ftTastung.? der Hochfrequenz mit den beiden Xontakten (1) und (2) syjnboliinert. Zwischen den einzelnen Verstärkern (3) werden vom 0awillator (4) gesteuerte Gleichrichter (9) angeordnet, an deren Ausgang eine pulsierende Gleichspannung der nächst niedreigeren Modulationsfrequenz auftritt, deren Wechselspannungs anteil im nachgeschalteten Verstärker weiterverstärkt wird.According to the invention, two improvements are made to eliminate this disadvantage stated: 1. Since the measuring effects are smaller than the noise voltages of the amplifier it is advisable to use an oscillator circuit to connect the capacitor to the capacitor to modulate generated high frequency. A multiple amplitude modulation (e.g. high frequency 10 MHz, 1st modulation frequency 455 kHz, 2nd modulation frequency 1no Hz keyed) made possible by the use of several more selective, on the respective frequency Matched amplifier provides sufficient suppression of noise voltages. A The block diagram is shown in Fig. 1. The effect of the modulation is here schematically as ftkeying.? the high frequency with the two Xontakten (1) and (2) syjnboliinert. Rectifiers controlled by the oscillator (4) are installed between the individual amplifiers (3) (9) arranged at the output of a pulsating DC voltage of the next lower Modulation frequency occurs, whose AC voltage component in the downstream Amplifier is further amplified.

Prinzipiell können die gesteuerten Gleichrichter auch - wie aus der Rundfunktechnik bekannt - durch Demodulatoren ersetzt werden 2. Zur Eliniination der # vom Verschiebungsstrom zwischen den Kondensatorplatten herrührenden induzierten Spannungen, die die nachgeschaltete Verstärkerkette übersteuern könnten, wird eine Meßwertgeberanordnung nach Fig.2 vorgeschlagen. Bei Ver- In principle, the controlled rectifiers can also - as from the Broadcast technology known - to be replaced by demodulators 2. For elimination the # induced resulting from the displacement current between the capacitor plates Tensions that could overdrive the downstream amplifier chain become a Proposed transducer arrangement according to Fig.2. In the event of

Claims (7)

P a t e n t a n s p r ü c h e Meßwertgeber zur Bestimmung der Strömungsgeschwindigkeit vom elektrisch isolierenden Flüssigkeiten, d a d u r c h g e k e n n -zeichnet, ist er aus einem, von einem iolierenden Rohr mit sei Metallbelägen gebildeten Kondensator besteht, auf dessen Seiten sich zwei Polschuhe befinden, die im Gegensatz zur Hauptanmeldung (P 22 63 717.8) durch z w e i mit Spulen versehenen Querjochen verbunden sind. P a t e n t a n s p r ü c h e transducer for determining the flow velocity from electrically insulating liquids, d u r c h g e n n n it is made up of a condenser formed by an insulating tube with metal coatings exists, on the sides of which there are two pole pieces, which in contrast to the main application (P 22 63 717.8) are connected by two cross yokes provided with coils. 2. Meßwertgeber nach Anspruch 1., dadurch gekennzeichnet, daß die beiden Spulen in Reihe geschaltet sind. 2. Transmitter according to claim 1, characterized in that the two coils are connected in series. 3. Meß.wertgeber nach Anspruch 1., dadurch sekennzeichnet, daß der aus den Polschuhen und Querjochen gebildete magnetische kreis eowohl von dem Verschiebungsstrom des Kondensators, als auch von dem Strom in den Zuleitungen in umgekehrter Richtung durchsetzt wird. 3. Mess.wertgeber according to claim 1, characterized in that the Magnetic circuit formed from the pole pieces and cross yokes both from the displacement current of the capacitor, as well as of the current in the supply lines in the opposite direction is enforced. 4, Meßwertgeber nach Anspruch 1., dadurch gekennzeichnet, daß anstatt der beiden Spulen auch ein Paar magnetisch empfindlicher Indikatoren, wie z.B. Hall-Generatoren und Feldplatten in Luftspalte der Querjoche eingebaut werden. 4, transducer according to claim 1, characterized in that instead of The two coils also have a pair of magnetically sensitive indicators, such as Hall generators and field plates are installed in the air gaps of the transverse yokes. 5. Oszillator zur Erzeugung der zum Betrieb des Meßwertgebers benötigten Spannung, dadurch gekennzeichnet, daß die absegebene Hochirequenz mehrfach moduliert, z.B. zweifach amplitudenmoduliert ist. 5. Oscillator to generate the necessary to operate the transducer Voltage, characterized in that the emitted high frequency modulates several times, e.g. is amplitude modulated twice. 6. Verstärkerkette zur Verstärkung der vom Meßwertgeber abgegebenen Spannung, dadurch gekennzeichnet, daß sie aus selektiven, auf die Modulationsfrequenzen und die Hochfrequenz abgestimmten Verstärkern aufgebaut ist. 6. Amplifier chain for amplifying the output from the transducer Voltage, characterized in that it consists of selective, on the modulation frequencies and the high frequency tuned amplifiers are constructed. 7. Verstärkerkette nach Anspruch 6., dadurch gekennzeichnet, daß jeweils zwischen zwei Verstärkern ein vom Oszillator gesteuerter Gleichrichter angeordnet ist, an dessen Au8-gang eine im Rhythmus der niedrigeren Modulationsfrequenz pulsierende Gleichspannung anfällt, deren Wechselspannungsanteil im nachfolgenden Verstärker weiter verstärkt wird. 7. amplifier chain according to claim 6, characterized in that A rectifier controlled by the oscillator is arranged between two amplifiers is, at the output of which a pulsating in the rhythm of the lower modulation frequency DC voltage occurs, the AC voltage component of which in the downstream amplifier is further strengthened. bindung der beiden Polschuhe (6) durch zwei Querjoch (7) mit den Spulen (8) (æ.B. je loo Windungen) wird in einer Spule die um die Störspannung erhöhte halbe Meßspannung, in der zweiten Spule die um die Störspannung verminderte halbe Meßspannung induziert. Die Addition beider Spulenspannungen liefert dann die von Störspannungen befreite Meßspannung.binding of the two pole shoes (6) through two cross yokes (7) with the coils (8) (æ.B. per loo turns) is increased by the interference voltage in a coil half the measuring voltage, in the second coil half the voltage reduced by the interference voltage Measurement voltage induced. The addition of the two coil voltages then provides that of Measurement voltage freed from interference voltages. Der Aufbau des Meßwertgebers wird so durchgeführt, daß der aus den beiden Polschuhen mit den Querjochen gebildete magnetieche Kreis sowohl von dem zwischen den Kondensatorplatten (9) fließenden Verschiebungsstrom, als auch In entgegengesetztes Richtung vom Leitungsstrom durchsetzt wird, sodaß dadurch schon eine weitgehende Kompensation der zu erwartenden Störspannungen erreicht wird.The structure of the transducer is carried out in such a way that the both pole pieces with the cross yokes formed magnetic circle both by the between the capacitor plates (9) flowing displacement current, as well as In opposite Direction is penetrated by the line current, so that thereby already a far-reaching Compensation of the expected interference voltages is achieved. Anstatt der beiden Spulen können auch andere vom Magnetfeld beeinflußte Indikatoren in Luftspalte der Querjoche eingebaut werden, wie z.B. Hall-Generatoren und Feldplatten.Instead of the two coils, other coils can also be influenced by the magnetic field Indicators are built into the air gaps of the transverse yokes, such as Hall generators and field plates.
DE2401811A 1974-01-12 1974-01-12 Flow velocity pickup for electrically insulating liquid - is capacitor consisting of insulating tube with two metal electrodes Ceased DE2401811A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE2401811A DE2401811A1 (en) 1974-01-12 1974-01-12 Flow velocity pickup for electrically insulating liquid - is capacitor consisting of insulating tube with two metal electrodes

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2401811A DE2401811A1 (en) 1974-01-12 1974-01-12 Flow velocity pickup for electrically insulating liquid - is capacitor consisting of insulating tube with two metal electrodes

Publications (1)

Publication Number Publication Date
DE2401811A1 true DE2401811A1 (en) 1975-07-17

Family

ID=5904847

Family Applications (1)

Application Number Title Priority Date Filing Date
DE2401811A Ceased DE2401811A1 (en) 1974-01-12 1974-01-12 Flow velocity pickup for electrically insulating liquid - is capacitor consisting of insulating tube with two metal electrodes

Country Status (1)

Country Link
DE (1) DE2401811A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3789741A1 (en) * 2019-09-03 2021-03-10 Krohne AG Magnetic-inductive flow meter and magnetic circuit device
CN113933532A (en) * 2021-10-12 2022-01-14 中国人民解放军国防科技大学 Device and method for measuring liquid flow velocity based on alternating magnetic field

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3789741A1 (en) * 2019-09-03 2021-03-10 Krohne AG Magnetic-inductive flow meter and magnetic circuit device
US11486746B2 (en) 2019-09-03 2022-11-01 Krohne Ag Magnetic-inductive flowmeter and magnetic circuit device
CN113933532A (en) * 2021-10-12 2022-01-14 中国人民解放军国防科技大学 Device and method for measuring liquid flow velocity based on alternating magnetic field

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