DE2214735A1 - ELECTRONIC FLOW METER FOR LIQUIDS - Google Patents
ELECTRONIC FLOW METER FOR LIQUIDSInfo
- Publication number
- DE2214735A1 DE2214735A1 DE19722214735 DE2214735A DE2214735A1 DE 2214735 A1 DE2214735 A1 DE 2214735A1 DE 19722214735 DE19722214735 DE 19722214735 DE 2214735 A DE2214735 A DE 2214735A DE 2214735 A1 DE2214735 A1 DE 2214735A1
- Authority
- DE
- Germany
- Prior art keywords
- measuring
- frequency
- capacitor
- oscillators
- liquids
- 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.)
- Pending
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/56—Measuring 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
- G01F1/64—Measuring 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
Description
ELEKTRONISCHER DURCHFLUSSMESSER FÜR FLÜSSIGKEITEN: 2. Beschreibung: A. Bereits bekannte Verfahren: Zur kapazitiven Messung von Flüssigkeitsdurchsatz durch ein Meßrohr verwendet man die Änderung der Kapazität eines Meßkondensators, der durch zwei Elektroden auf dem selben Meßrohr gebildet wird. Die durchlaufende Flüssigkeit ändert das Dielektrikum und damit die Kapazität des Meßkondensators. Diese Kapazitätsänderung wird verwendet, um aktive oder passive Schwingkreise zu verstimmen. Aus dieser Verstimmung wird durch verschiedene Methoden eine Spannungs- oder Stromänderung abgeleitet, die registriert oder angezeigt werden kann.ELECTRONIC FLOW METER FOR LIQUIDS: 2. Description: A. Already known methods: For capacitive measurement of liquid throughput through a measuring tube one uses the change in the capacitance of a measuring capacitor, which is formed by two electrodes on the same measuring tube. The continuous Liquid changes the dielectric and thus the capacitance of the measuring capacitor. This change in capacitance is used to create active or passive resonant circuits upset. Various methods are used to turn this detuning into a voltage or current change derived, which can be registered or displayed.
Nachteile dieser Verfahren: Die vom Meßkreis gesteuerten Oszillatoren sind nicht konstant. Speisespannungs- oder Temperaturänderungen lassen die erzeugte Frequenz driften, so daß ein konstanter Nullpunkt oder Vollausschlag nicht über längere Zeit gewährleistet ist. Damit ist die Meßgenauigkeit dieser Verfahren begrenzt.Disadvantages of this method: The oscillators controlled by the measuring circuit are not constant. Supply voltage or temperature changes leave the generated Frequency drift so that a constant zero point or full scale does not exceed is guaranteed for a longer period of time. This limits the measurement accuracy of this method.
B. Beschreibung der Erfindung: Die Meßanordnung der Erfindung verwendet nicht einen, sondern zwei Oszillatoren, die elektrisch und mechanisch völlig gleich aufgebaut sind. Der frequenzbestimmende Teil ("Meßkondensator") ist doppelt vorhanden und zweckmäßigerweise im selben Block vergossen. Die beiden Frequenzen werden einem Mischer (Mixer) zugeführt und die entstehende Schwebung i - f2 enthält die Meßinformation, da nur einer der beiden Meßkondensatoren mit der zu messenden Flüssigkeit beaufschlagt wird. Damit ändert sich nur die Frequenz des zugehörigen Oszillators. Der zweite Meßkondensator dient als feste Referenzkapazität. In Folge des völlig gleichen Aufbaues beider Meßkondensatoren und der zugehörigen Oszillatoren ist der Temperaturgang und die Abhängigkeit von der Speisespannung der Frequenz in beiden Aggregaten identisch.B. Description of the Invention: The measuring arrangement of the invention is used not one, but two oscillators that are electrically and mechanically identical are constructed. The frequency-determining part ("measuring capacitor") is available twice and expediently cast in the same block. The two frequencies become one Mixer (mixer) supplied and the resulting beat i - f2 contains the measurement information, because only one of the two measuring capacitors is acted upon by the liquid to be measured will. This only changes the frequency of the associated oscillator. The second Measuring capacitor serves as a fixed reference capacitance. As a result of the completely identical structure of both measuring capacitors and the associated oscillators is the temperature response and the dependence on the supply voltage of the frequency is identical in both units.
ELEKTRONISCHER DURCHPLUSSMESSER FÜR FLÜSSIGKEITEN: 2. Beschreibung: (Fortsetzung) Falls Temperatur- oder Speisespannungsänderungen eine Frequenzänderung der Oszillatoren hervorrufen, driften beide nach der selben Richtung, so daß die Schwebungsfrequenz ausschließlich von der Beaufschlagung des Meßkondensators mit der zu messenden Flüssigkeit abhängt, Die entstehende Schwebungsfrequenz ist also eine Funktion der im Meßkondensator vorhandenen Flüssigkeitsmenge. Eine Eichung der Anzeigevorrichtung (im einfachsten Falle ein Frequenzmesser) ist also dadurch möglich, daß die Anzeige bei leerem und bei völlig mit Flüssigkeit gefülltem Meßkondensator aufgenommen wird.ELECTRONIC FLOW METER FOR LIQUIDS: 2. Description: (Continued) If temperature or supply voltage changes, a frequency change of the oscillators both drift in the same direction, so that the Beat frequency exclusively from the application of the measuring capacitor depends on the liquid to be measured, so the resulting beat frequency is a function of the amount of liquid present in the measuring capacitor. A calibration the display device (in the simplest case a frequency meter) is thus It is possible that the display will appear when the measuring capacitor is empty and when the measuring capacitor is completely filled with liquid is recorded.
Dadurch ergeben sich 0 und 100% Durchsatz.This results in 0 and 100% throughput.
Die Grundfrequenz der beiden Oszillatoren fi und £2 muß im Vergleich zu der entstehenden Schwebung genügend hoch sein, um lineare Verhältnisse zu erhalten.The fundamental frequency of the two oscillators fi and £ 2 must be compared must be sufficiently high for the resulting beat to obtain linear relationships.
Die die Meßinformation enthaltende Schwebung wird dann in bekannter Weise (wie unter A.) weiterverarbeitet.The beat containing the measurement information is then known Way (as under A.) further processed.
Claims (1)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19722214735 DE2214735A1 (en) | 1972-03-25 | 1972-03-25 | ELECTRONIC FLOW METER FOR LIQUIDS |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19722214735 DE2214735A1 (en) | 1972-03-25 | 1972-03-25 | ELECTRONIC FLOW METER FOR LIQUIDS |
Publications (1)
Publication Number | Publication Date |
---|---|
DE2214735A1 true DE2214735A1 (en) | 1973-09-27 |
Family
ID=5840217
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DE19722214735 Pending DE2214735A1 (en) | 1972-03-25 | 1972-03-25 | ELECTRONIC FLOW METER FOR LIQUIDS |
Country Status (1)
Country | Link |
---|---|
DE (1) | DE2214735A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2450600A1 (en) * | 1973-11-05 | 1975-05-28 | Surface Systems | WET AND ICE DETECTION SYSTEM |
EP0106940A2 (en) * | 1982-09-28 | 1984-05-02 | Gambro Lundia AB | An arrangement for the measurement of the difference between two flows in two separate ducts |
EP0447985A1 (en) * | 1990-03-15 | 1991-09-25 | Abbott Laboratories | Positive displacement pump |
DE10238168B4 (en) * | 2002-02-14 | 2006-10-26 | Peter Schwarz | Wischfeld independent, sensor-controlled windscreen wiper system for vehicles with window |
-
1972
- 1972-03-25 DE DE19722214735 patent/DE2214735A1/en active Pending
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2450600A1 (en) * | 1973-11-05 | 1975-05-28 | Surface Systems | WET AND ICE DETECTION SYSTEM |
EP0106940A2 (en) * | 1982-09-28 | 1984-05-02 | Gambro Lundia AB | An arrangement for the measurement of the difference between two flows in two separate ducts |
EP0106940A3 (en) * | 1982-09-28 | 1984-07-18 | Gambro Lundia Ab | An arrangement for the measurement of the difference between two flows in two separate ducts |
EP0447985A1 (en) * | 1990-03-15 | 1991-09-25 | Abbott Laboratories | Positive displacement pump |
DE10238168B4 (en) * | 2002-02-14 | 2006-10-26 | Peter Schwarz | Wischfeld independent, sensor-controlled windscreen wiper system for vehicles with window |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
OHJ | Non-payment of the annual fee |