DE3023534A1 - Liq. level indicator avoiding ultrasonic measurement amplitude maxima - by frequency modulation of transducer and using band-pass filter - Google Patents

Liq. level indicator avoiding ultrasonic measurement amplitude maxima - by frequency modulation of transducer and using band-pass filter

Info

Publication number
DE3023534A1
DE3023534A1 DE19803023534 DE3023534A DE3023534A1 DE 3023534 A1 DE3023534 A1 DE 3023534A1 DE 19803023534 DE19803023534 DE 19803023534 DE 3023534 A DE3023534 A DE 3023534A DE 3023534 A1 DE3023534 A1 DE 3023534A1
Authority
DE
Germany
Prior art keywords
frequency
level indicator
ultrasonic
transducer
liquid level
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
DE19803023534
Other languages
German (de)
Inventor
Heinz 5020 Frechen Buschmann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
HEINRICHS MESSGERAETE JOSEF
Original Assignee
HEINRICHS MESSGERAETE JOSEF
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 HEINRICHS MESSGERAETE JOSEF filed Critical HEINRICHS MESSGERAETE JOSEF
Priority to DE19803023534 priority Critical patent/DE3023534A1/en
Publication of DE3023534A1 publication Critical patent/DE3023534A1/en
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/28—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
    • G01F23/296—Acoustic waves
    • G01F23/2968—Transducers specially adapted for acoustic level indicators

Landscapes

  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Electromagnetism (AREA)
  • Thermal Sciences (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)

Abstract

A liq. level indicator with an ultrasonic transmitter and receiver indicates when a certain level is reached or gives a continuous level indication. It overcomes the difficulties inherent in similar systems caused by amplitude maxima at various frequencies by using a modulated tramsitter with a defined frequency shift and a receiver with an appropriately adjusted input bandwidth. In addition tothe frequency modulation there is a clocking generator used for coding with a defined clock frequency. The ratio of ultrasonic transducer average frequency to modulation frequency to clocking frequency is approx. 1000:100:1. The receiver bandwidth is achieved using a bandpass filter for the transducer mean frequency plus the frequency increase. The transducer frequency is identified by a further bandpass filter tuned for the clock frequency.

Description

Flüssigkeitsstandanzeiger Liquid level indicator

Die Erfindung betrifft Flüssigkeitsstandanzeiger oder dergleichen MeßgerMite, und zwar Geräte mit einem Ultraschall-Geber und einem Ultraschall-Empfänger, wie sie dazu benutzt werden, das Erreichen eines vor£egebenen Flüssgkeitsstandes anzuzeigen oder eine laufende Anzeige des jeweiligen Flüssigkeitsstandes durchzuführen. The invention relates to liquid level indicators or the like MeßgerMite, namely devices with an ultrasonic transmitter and an ultrasonic receiver, how they are used to achieve a given fluid level display or carry out a continuous display of the respective liquid level.

Bei derartigen Geräten arbeitet der Ultraschall-Geber üblicherweise mit einer festen Frequenz. Es zeigt sich nun, daß das vom Ultraschall-Geber abgegebene Signal beim Durchlaufen der Meßstrecke Änderungen erfährt, auf Grund deren auf der Empfangerseite außer der Geber-Frecuenz mehrere Amplituden-Maxima mit von der Geber-Frecuenz abreichender Frequenz auftreten, die über einen bestimmten Frequenzbereich verteilt sind. Diese Maxima sind nach Amplitude und Frequenz von den mannigfachsten Faktoren abhängig, wobei die Dicke des Ultraschall-Gebers, die S.nkopplung des Ultraschall-Kristalls an das Gerät, Abmessungen des Geräts beispielsweise hinsichtlich der Wandstarke, Dichte der MeßflüssiSkeit und dergleichen von Bedeutung sein können. Besonders wesentlich ist hierbei, daP, die ganze Anordnung in der Pegel noch einen starken Temperaturgang aufweist, wodurch die Lage der Maxima verschoben wird. In such devices, the ultrasonic transmitter usually works with a fixed frequency. It shows now that this is from the ultrasonic transducer given signal when passing through the measuring section experiences changes, due to on the receiver side, in addition to the encoder frequency, there are several amplitude maxima occur with a frequency reaching from the encoder frequency that is above a certain Frequency range are distributed. These maxima are according to amplitude and frequency of depends on the most diverse factors, with the thickness of the ultrasonic transducer, the Coupling of the ultrasonic crystal to the device, dimensions of the device, for example with regard to the wall thickness, density of the measuring liquid and the like could be. It is particularly important here that the entire arrangement in the level still has a strong temperature drift, which shifts the position of the maxima will.

Die Anzeige derartiger Geräte ist daher in vielen Fällen unbefriedigend.The display of such devices is therefore unsatisfactory in many cases.

Zur Vermeidung dieser Mängel sieht die Erfindung bei einem Gerät der eingangs genannten Art einen mit einem vorgegebenen Frequenzhub modulierbaren Ultraschall-Geber und einen diesem Frequenzhub in der Eingangsbandbreite angepaßten Ultraschall-Empfänger vor. Hierbei erpflehlt es. To avoid these shortcomings, the invention provides an apparatus of the type mentioned at the outset, one that can be modulated with a predetermined frequency deviation Ultrasonic encoder and one that is adapted to this frequency deviation in the input bandwidth Ultrasonic receiver in front. Here it is recommended.

sich, zusätzlich zu der Frequenz-Modulation mit vorgegebener Wobbelfrequenz noch eine Taktung mit bestimmter Taktfrequenz vorzunehmen, um Störeinflüsse, wie sie durch Körperschall oder Einstreuungen entstehen können, weitgehend auszuschalten und eine bessere Identifizierung des Gebersigr.als zu ermöglichen. Der Ultraschall-Seber sollte daher mit einem als Kodiereinrichtung arbeitenden Taktgenerator ausgerilstet sein. Das Verhältnis von Geber-Mittel-Frequenz zu Wobbelfrequenz zu Taktfrequenz kann etwa 1000 : 100 : 1 betragen.itself, in addition to the frequency modulation with a given wobble frequency still make a clocking with a certain clock frequency to avoid interference, such as it through structure-borne noise or interference can arise, largely off and enable better identification of the encoder signal. The ultrasonic Seber should therefore be equipped with a clock generator working as a coding device be equipped. The ratio of transducer center frequency to wobble frequency to Clock frequency can be around 1000: 100: 1.

Im Ultraschall-En.pfängereingang kann ein Bandpaß für die Geber-Mittel-Frequenz zuzüglich der durch den Frequenzgeber bewirkten Frequenzerhöhung angeordnet sein. Ein weiterer, auf die Taktfrequenz abgestimmter Bandpaß kann in Verbindung mit einem Gleichrichter als Dekodierer zur Identifizierung der Geberfrequenz vorgesehen sein.In the ultrasonic receiver input a bandpass filter for the transmitter center frequency plus the frequency increase caused by the frequency generator. Another band-pass filter, matched to the clock frequency, can be used in conjunction with a Rectifiers can be provided as a decoder to identify the encoder frequency.

Die Erfindung soll nun an Hand eines AusführunUsbeispiels, das durch ein Blockschema veranschaulicht ist, näher erläutert werden, wobei nur Ultraschall-Geber und Ultraschall-Empfänger, soweit sie zum Verständnis der Erfindung wesentlich sind, in ihrem Aufbau schematisch dargesteilt sind. The invention will now be based on an exemplary embodiment, which by a block diagram is illustrated, explained in more detail, with only ultrasonic transducers and ultrasonic receivers, insofar as they are essential for understanding the invention, are shown schematically in their structure.

Bei dem dargestellten Ausführungsbeispiel ist von einem Ultraschall-Geber 11 ausgegangen, dessen Generator 12 für die Grundschwingung durch einen Wobbelzusatz 13 mit einer vorgegebenen Frequenz und einem vorzegebenen Frequenzhub modulierbar ist. Es sei angenommen, daß die Grur.dschwingung 800 kHz, die Wobbelfrequenz 100 kHz und der Frequenzhub + 200 kHz betragen. Das frequenzmcdulierte Signal wird zur Kodierung durch einen Taktgenerator 14 mit einer Frequenz von beisplelsweise 1 kHz getaktet und über einen Verstärker 15 dem IJltraschall-Schwinger 16 zugeführt, der üblicherweise ein Piezokristall ist. Dieser Kristall ist an die Meßstrecke angekoppelt, die in der Zeichnung durch die beiden strichpunktierten Linien 17 angedeutet ist. In the illustrated embodiment is from an ultrasonic transmitter 11 assumed its generator 12 for the fundamental oscillation by means of a wobble addition 13 can be modulated with a predetermined frequency and a predetermined frequency deviation is. It is assumed that the basic vibration is 800 kHz, the wobble frequency 100 kHz and the Frequency deviation + 200 kHz. The frequency mcdulated Signal is used for coding by a clock generator 14 at a frequency of, for example 1 kHz clocked and fed to the ultrasonic transducer 16 via an amplifier 15, which is usually a piezo crystal. This crystal is coupled to the measuring section, which is indicated in the drawing by the two dash-dotted lines 17.

Die vom Ultraschall-Geber 11 abgegebenen Signale gelangen nach Durchlaufen der ieePstreclre 17 an den Ultraschall-Empfänger 18 und werden über einen Bandpaß 19 einem breitbandigen Verstärker 20 zugeführt, als dessen Eingang der Bandpaß 19 dient. Das verstärkte Signal wird der Dekodiereinrichtung 21 zugeleitet, die im wesentlicher. The signals emitted by the ultrasonic transmitter 11 arrive after they have passed through the ieePstreclre 17 to the ultrasonic receiver 18 and are over a band pass 19 is fed to a broadband amplifier 20, the input of which is the bandpass filter 19 serves. The amplified signal is fed to the decoder 21, which is im more essential.

von einem Gleichrichter 211 mit nachgeschaltetem, auf die Taktfrequenz abgestimmten Bandpaß 212 gebildet wird. Das ausgefilterte Signal gelangt über einen weiteren Verstärker 22 und Gleichrichter 23 an das Anzeigeinstrur.ent 24.from a rectifier 211 with a downstream, to the clock frequency matched bandpass filter 212 is formed. The filtered signal comes through a further amplifier 22 and rectifier 23 to the display device 24.

Claims (5)

Flüssigkeitsstandanzeiger Ansprüche 1. Flüssigkeitsstandanzeiger oder dergleichen Meßgerät mit einem Ultraschall-Geber und einem Ultraschall-Empfänger, dadurch gekennzeichnet, daß der Ultraschall-Geber mit einem vorgegebenen Frequenzhub in seiner Frequenz modulierbar ist und der Ultraschall-Empfänger in der Eingangsbandbreite diesem Frequenzhub anpaßbar ist. Liquid level indicator claims 1. Liquid level indicator or similar measuring device with an ultrasonic transmitter and an ultrasonic receiver, characterized in that the ultrasonic transmitter has a predetermined frequency deviation can be modulated in its frequency and the ultrasonic receiver in the input bandwidth is adaptable to this frequency deviation. 2. Flüssiggeitsstandanzeiger oder dergleichen nach Anspruch 1, dadurch gekennzeichnet, daß zusätzlich zur Frequenzmodulation mit vorgegebener Wobbelfrequenz ein als Kodiereinrichtung arbeitender Taktgenerator zur Taktung mit vorgegebener Taktfrequenz vorgesehen ist. 2. Liquid level indicator or the like according to claim 1, characterized characterized in that in addition to frequency modulation with a predetermined wobble frequency a clock generator working as a coding device for clocking with a predetermined Clock frequency is provided. 3. Flüssigkeitsstandanzeiger oder dergleichen nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß das Verhältnis von Ultraschall-Geber-Mittel-Frequenz zu Wobbelfrequenz zu Taktfrequenz etwa 1000 : 100 : 1 beträgt. 3. Liquid level indicator or the like according to claim 1 or 2, characterized in that the ratio of the ultrasonic transducer mean frequency to wobble frequency to clock frequency is about 1000: 100: 1. 4. Flussigkeitsstandanzeiger oder dergleichen nach einem oder mehreren der Ansprüche 1 bis 3, gekennzeichnet durch einen am Ultraschall-Emp fängereingang zur Erzielung ausreichender Bandbreite angeordneten Bandpaß für die Geber Mittel-Frequenz zuzüglich der durch den Frequenzhub bewirkten Frequenzerhöhung. 4. Liquid level indicator or the like according to one or more of claims 1 to 3, characterized by a catcher input on the ultrasonic Emp Bandpass filter for the transmitter center frequency arranged to achieve sufficient bandwidth plus the frequency increase caused by the frequency deviation. 5. Flüssigkeitsstandanzeiger oder dergleichen nach einem oder mehreren der Ansprüche 1 bis 4, gekennzeichnet durch einen weiteren, auf die Taktfrequenz abgestimmten, in Verbindung mit einem Gleichrichter als Dekodierer zur Identifizierung der Geberfrequenz dienenden Bandpaß im Ultraschall-Empfänger. 5. Liquid level indicator or the like according to one or more of claims 1 to 4, characterized by a further, based on the clock frequency matched, in conjunction with a rectifier as a decoder for identification The bandpass filter used for the transmitter frequency in the ultrasonic receiver.
DE19803023534 1980-06-24 1980-06-24 Liq. level indicator avoiding ultrasonic measurement amplitude maxima - by frequency modulation of transducer and using band-pass filter Ceased DE3023534A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE19803023534 DE3023534A1 (en) 1980-06-24 1980-06-24 Liq. level indicator avoiding ultrasonic measurement amplitude maxima - by frequency modulation of transducer and using band-pass filter

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19803023534 DE3023534A1 (en) 1980-06-24 1980-06-24 Liq. level indicator avoiding ultrasonic measurement amplitude maxima - by frequency modulation of transducer and using band-pass filter

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DE3023534A1 true DE3023534A1 (en) 1982-01-21

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3311982A1 (en) * 1982-04-01 1983-10-13 Battelle Memorial Institute, 1227 Carouge, Genève METHOD FOR DETERMINING THE LIQUID VOLUME CONTAINED IN A CLOSED CONTAINER AND DEVICE FOR CARRYING OUT THIS METHOD
DE19520516A1 (en) * 1994-06-08 1995-12-14 Bindicator Co Ultrasonic material level measurement
DE19711093C2 (en) * 1996-09-23 2002-04-11 Reich Kg Regel & Sicherheits Device for determining the content of a gas bottle

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE958776C (en) * 1951-06-16 1957-02-21 Electroacustic Ges M B H Determination of filling height in bunkers
FR1514156A (en) * 1966-11-08 1968-02-23 Realisations Ultrasoniques Sa Ultrasonic pulse reflection level meter

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE958776C (en) * 1951-06-16 1957-02-21 Electroacustic Ges M B H Determination of filling height in bunkers
FR1514156A (en) * 1966-11-08 1968-02-23 Realisations Ultrasoniques Sa Ultrasonic pulse reflection level meter

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3311982A1 (en) * 1982-04-01 1983-10-13 Battelle Memorial Institute, 1227 Carouge, Genève METHOD FOR DETERMINING THE LIQUID VOLUME CONTAINED IN A CLOSED CONTAINER AND DEVICE FOR CARRYING OUT THIS METHOD
DE19520516A1 (en) * 1994-06-08 1995-12-14 Bindicator Co Ultrasonic material level measurement
DE19520516C2 (en) * 1994-06-08 2001-06-07 Venture Measurement Co Llc Por Device for displaying a material level
DE19711093C2 (en) * 1996-09-23 2002-04-11 Reich Kg Regel & Sicherheits Device for determining the content of a gas bottle

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