DE2429482B2 - Device for measuring and / or monitoring temperatures, levels and / or flow conditions of electrically conductive liquids of high specific heat - Google Patents

Device for measuring and / or monitoring temperatures, levels and / or flow conditions of electrically conductive liquids of high specific heat

Info

Publication number
DE2429482B2
DE2429482B2 DE19742429482 DE2429482A DE2429482B2 DE 2429482 B2 DE2429482 B2 DE 2429482B2 DE 19742429482 DE19742429482 DE 19742429482 DE 2429482 A DE2429482 A DE 2429482A DE 2429482 B2 DE2429482 B2 DE 2429482B2
Authority
DE
Germany
Prior art keywords
measuring
electrically conductive
high specific
specific heat
levels
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.)
Granted
Application number
DE19742429482
Other languages
German (de)
Other versions
DE2429482A1 (en
DE2429482C3 (en
Inventor
Wolfgang Dipl.-Ing. Deutschlandsberg Brueckner (Oesterreich)
Winfried Dipl.-Phys. 8000 Muenchen Grube
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.)
Siemens AG
Original Assignee
Siemens AG
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 Siemens AG filed Critical Siemens AG
Priority to DE19742429482 priority Critical patent/DE2429482C3/en
Priority to AT364075A priority patent/AT338015B/en
Publication of DE2429482A1 publication Critical patent/DE2429482A1/en
Publication of DE2429482B2 publication Critical patent/DE2429482B2/en
Application granted granted Critical
Publication of DE2429482C3 publication Critical patent/DE2429482C3/en
Expired legal-status Critical Current

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
    • G01F1/68—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 thermal effects
    • G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
    • G01F1/688—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow using a particular type of heating, cooling or sensing element
    • G01F1/69—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow using a particular type of heating, cooling or sensing element of resistive type
    • G01F1/692—Thin-film arrangements
    • 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
    • G01F1/68—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 thermal effects
    • G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
    • 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
    • G01F1/68—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 thermal effects
    • G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
    • G01F1/6847—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow where sensing or heating elements are not disturbing the fluid flow, e.g. elements mounted outside the flow duct
    • 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
    • G01F23/24—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 variations of resistance of resistors due to contact with conductor fluid
    • G01F23/246—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 variations of resistance of resistors due to contact with conductor fluid thermal devices
    • G01F23/247—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 variations of resistance of resistors due to contact with conductor fluid thermal devices for discrete levels
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
    • G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
    • G01K7/22—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a non-linear resistance, e.g. thermistor
    • G01K7/223—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a non-linear resistance, e.g. thermistor characterised by the shape of the resistive element
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P5/00—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
    • G01P5/10—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring thermal variables
    • G01P5/12—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring thermal variables using variation of resistance of a heated conductor

Description

Die Erfindung betrifft eine Vorrichtung zum Messen und/oder Überwachen von Temperaturen, Niveauhöhen und/oder Strömungszuständen elektrisch leitfähiger Flüssigkeiten hoher spezifischer Wärme, insbesondere von Wasser, welche als Fühler einen temperaturabhängigen Widerstand mit Klemmkontaktierung besitzt, welcher zur Isolierung mit einem Schrumpfschlauch umhüllt ist.The invention relates to a device for measuring and / or monitoring temperatures and levels and / or flow states of electrically conductive liquids of high specific heat, in particular of water, which as a sensor has a temperature-dependent resistance with terminal contact, which is covered with a shrink tube for insulation.

Aus der DE-OS 21 07 365 ist eine schrumpfschlauchumhüllte Kaltleiterkombination mit Klemmkontaktierung für die Entmagnetisierung von Farbfernsehgeräten bekannt. Ein derartiger Aufbau eignet sich nicht zum Einsatz in elektrisch leitfähigen Fiüssigkeiten hoher spezifischer Wärme, da die Umhüllung an einer Seite offen ist und da andererseits die Kontaktierung der Kaltleiter nur an sehr kleinen Flächen erfolgt. Dies hat zur Folge, daß der Wärmeübergang von der Kontaktelektrode auf den Kaltleiter sehr gering ist, was eine große Zeitkonstante der Kombination zur Folge hat. Unter Zeitkonstante wird hierbei diejenige Zeit verstanden, die der Kaltleiter benötigt, bis seine Temperatur derjenigen der Umgebung angepaßt ist.From DE-OS 21 07 365 is a shrink tubing wrapped PTC thermistor combination with clamp contact known for demagnetizing color televisions. Such a structure is not suitable for Use in electrically conductive liquids with high specific heat, as the casing is on one side is open and since, on the other hand, the PTC thermistors are only contacted on very small areas. this has with the result that the heat transfer from the contact electrode to the PTC thermistor is very low, which is a results in a large time constant of the combination. Time is the time here understood that the PTC thermistor needs until its temperature is adapted to that of the environment.

Weiterhin sind aus der »Siemens-Zeitschrift« 1969, Heft 4, S. 392 bis 394, und Heft 9, S. 793 bis 796, Kaltleiter mit Schrumpfschlauchumhüllung bekannt. Die bekannten Kaltleiter dienen zur Temperaturüberwachung und zum Übertemperaturschutz für temperaturgefährdete Maschinen und Einrichtungen, insbesondere Elektromotoren. Die bekannten schrumpfschlauchumhiillten Kaltleiter haben angelötete Anschlußdrähte und weisen eine Kunststoffisolierung auf. Sie eignen sich nicht zum Einsatz in Flüssigkeiten hoher spezifischer Wärme, da beim Eintauchen des Fühlers der Temperaturschock so stark ist, daß nach einigen Meßtakten Ablösung der Lötstellen eintreten kann.Furthermore, from the "Siemens magazine" 1969, issue 4, p. 392 to 394, and issue 9, p. 793 to 796, PTC thermistors known with shrink tubing. The known PTC thermistors are used for temperature monitoring and for overtemperature protection for machines and equipment at risk from high temperatures, especially electric motors. The known shrink-tubing PTC thermistors have soldered connection wires and have a Plastic insulation. They are not suitable for use in liquids with a high specific heat, because When the probe is immersed, the temperature shock is so strong that after a few measuring cycles the Solder joints can occur.

Aufgabe der Erfindung ist es, eine Vorrichtung zum Messen und/oder Überwachen von Temperaturen, Niveauhöhen und/oder Strömungszuständen elektrisch leitfähiger Flüssigkeiten anzugeben, mit welcher die vorstehend aufgeführten Schwierigkeiten umgangen werden.The object of the invention is to provide a device for measuring and / or monitoring temperatures, Indicate level heights and / or flow states of electrically conductive liquids with which the difficulties listed above can be circumvented.

Dies wird bei der eingangs beschriebenen Vorrichtung erfindungsgemäß dadurch gelöst, daß die Kontaktelektroden aus federnden Blechstreifen bestehen, deren eines Ende mit dem Ende einer als Stromzuführung dienenden Litze verlötet ist, und welche spiralförmig um dieses Ende der Litze aufgewickelt sind, und daß das offene Ende des Schrumpfschlauches mit einen; Kunststofftropfen verschlossen istIn the device described at the outset, this is achieved according to the invention in that the contact electrodes consist of resilient sheet metal strips, one end of which with the end of a power supply serving braid is soldered, and which are spirally wound around this end of the braid, and that the open end of the shrink tube with a; Plastic drop is closed

Als temperaturabhängiger Widerstand kann entweder ein Heißleiter oder ein Kaltleiter verwendet werden.Either a thermistor or a PTC thermistor can be used as the temperature-dependent resistor will.

Die Vorteile der Erfindung werden anhand der Zeichnung, welche ein Ausführungsbeispiel der erfindungsgemäßen Vorrichtung darstellt, aufgezeigt. In den zugehörigen Figuren zeigtThe advantages of the invention are based on the drawing, which shows an embodiment of the invention Device is shown. In the accompanying figures shows

Fi g. 1 einen Längsschnitt durch die erfindungsgemäße Vorrichtung undFi g. 1 shows a longitudinal section through the inventive Device and

Fig.2 einen Querschnitt längs der Ebene H-II der Fig. 1.2 shows a cross section along the plane H-II of Fig. 1.

In den Fig. 1 und 2 ist mit 11 eine Kaltleiterscheibe bezeichnet, die eine sperrschichtfreie Metallbelegung 12 aufweist. Die Anschlußlitzen 13 sind an ihrem oberen Ende abisoliert; an dieses obere Ende ist ein Blechstreifen 14 angelötet und spiralförmig um das Ende heiumgewickelt. Als Material für den Blechstreifen 14 wird dabei vorzugsweise verzinnte Bronzefolie von 0,2 mm Dicke verwendet.In FIGS. 1 and 2, 11 is a PTC thermistor which has a metal coating 12 free of a barrier layer. The pigtails 13 are at their upper Stripped end; a sheet metal strip 14 is soldered to this upper end and spiraled around the End wrapped in hot water. As a material for the sheet metal strip 14 tinned bronze foil 0.2 mm thick is preferably used.

Die spiralförmig aufgewickelten Blechstreifen 14 werden mittels des als Umhüllung und Isolierung dienenden Schrumpfschlauches 15 gegen die metallisierten Kaitleiterflächen gedrückt. Durch die Federwirkung der Blechstreifen entsteht dabei ein bei allen auftretenden Betriebsbedingungen sicherer Kontakt, welcher insbesondere durch den Temperaturschock beim Eintauchen in die Flüssigkeit hoher spezifischer Wärme nicht zerstört werden kann. Andererseits gewährt der spiralförmig aufgewickelte Blechstreifen 24 durch seine großflächige Kontaktstellen einen guten Wärmeübergang, so daß die Vorrichtung eine niedrige Zeitkonstante aufweistThe spirally wound sheet metal strips 14 are used as sheathing and insulation serving shrink tube 15 pressed against the metallized Kaitleiterflächen. By the spring action the sheet metal strip creates a secure contact under all operating conditions that occur in particular due to the temperature shock when immersed in the liquid with high specific heat cannot be destroyed. On the other hand, the spirally wound sheet metal strip 24 grants by its large contact points a good heat transfer, so that the device has a low time constant having

Um die für die Niveauabtastung und -messung erforderliche Dichtheit herzustellen, wird das offene Ende des Schrumpfschlauches 15 mittels eines Kunststofftropfens 16 verschlossen.In order to produce the tightness required for level sensing and measurement, the open The end of the shrink tube 15 is closed by means of a plastic drop 16.

Beim Betrieb wird der Kaltleiter durch eine angelegte Meßspannung bis in den Temperaturbereich des steilen Widerstandsanstiegs aufgeheizt, wobei im Strom-Spannungs-Diagramm dieser Betriebszustand im Gebiet fallender Strom-Spannungs-Kennlinie liegt. Da in Flüssigkeit mehr Wärme abgeführt werden kann, befindet sich der Kaltleiter auf einer niedrigeren Temperatur als in Luft, d. h. er weist in Flüssigkeit einen niedrigeren Widerstandswert auf. Daraus resultiert ein größerer Strom durch den Kaltleiter, wenn er sich in Flüssigkeit befindet.During operation, the PTC thermistor is brought into the temperature range of the steep by an applied measuring voltage Resistance rise heated, with this operating state in the area in the current-voltage diagram falling current-voltage characteristic. Since more heat can be dissipated in liquid, the PTC thermistor is at a lower temperature than in air, i.e. H. he shows one in liquid lower resistance value. This results in a larger current through the PTC thermistor when it is in Liquid is located.

Bei einem Ausführungsbeispiel der erfindungsgemäßen Vorrichtung wurde ein Kaltleiter der Nenntemperatur (Beginn des steilen Widerstandsanstiegs) von 80° C verwendet, welcher bei 250C einen Widerstandswert von 60 Ohm hatte. Bei dieser Ausführungsform ergaben sich bei einer angelegten Spannung von 20 V in Luft Strom werte von etwa 10 mA und in Wasser solche von ungefähr 50 mA.In one embodiment of the inventive device, a PTC thermistor of the nominal temperature (beginning of the steep rise in resistance) of 80 ° C is used, which at 25 0 C had a resistance value of 60 ohms. In this embodiment, an applied voltage of 20 V resulted in current values of approximately 10 mA in air and of approximately 50 mA in water.

Für andere Flüssigkeiten ergeben sich je nach Wärmewiderstand andere, aber ähnliche Werte.For other liquids, different but similar values result depending on the thermal resistance.

Schaltungen, in denen die erfindungsgemäße Vorrichtung eingesetzt werden kann, sind z. B. in der DT-PS 15 73 085. die eine elektronische ThermistorkomDensa-Circuits in which the device according to the invention can be used are, for. B. in the DT-PS 15 73 085. the one electronic thermistor controller

tionsschaltung zur Überfüllsicherung von Flüssigkeitstanks betrifft, und in der DT-PS 15 73 090, die ein Verfahren und eine Schaltungsanordnung zur Sicherung von Flüssigkeitstariks gegen Überfüllung betrifft, beschrieben.tion circuit for overfill protection of liquid tanks concerns, and in DT-PS 15 73 090, which a Process and a circuit arrangement for securing liquid tariffs against overfilling concerns, described.

Hierzu 1 Blatt Zeichnungen1 sheet of drawings

Claims (2)

Patentansprüche:Patent claims: 1. Vorrichtung zum Messen und/oder Überwachen von Temperaturen, Niveauhöhen und/oder Strömungszuständen elektrisch leitfähiger Flüssigkeiten hoher spezifischer Wärme, insbesondere von Wasser, welche als Fühler einen temperaturabhängigen Widerstand mit Klemmkontaktierung besitzt, welcher zur Isolierung mit einem Schrumpfschlauch umhüllt ist, dadurch gekennzeichnet, daß die Kontaktelektroden aus federnden Blechstücken (14) bestehen, deren eines Ende mit dem Ende einer als Stromzuführung dienenden Litze (15) verlötet ist, und welche spiralförmig um dieses Ende der Litze aufgewickelt sind und daß das offene Ende des Schrumpfschlauches (15) mit einem Kunststofftropfen (16) verschlossen ist.1. Device for measuring and / or monitoring temperatures, levels and / or Flow states of electrically conductive liquids of high specific heat, in particular of Water, which as a sensor has a temperature-dependent resistance with terminal contact, which is covered with a shrink tube for insulation, characterized in that the contact electrodes consist of resilient sheet metal pieces (14), one end of which with the end of a as a power supply serving braid (15) is soldered, and which spiral around this end of the braid are wound up and that the open end of the shrink tube (15) with a plastic drop (16) is closed. 2. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß die federnden Blechstreifen (14) aus verzinnter Bronzefolie bestehen.2. Apparatus according to claim 1, characterized in that the resilient sheet metal strips (14) from tinned bronze foil.
DE19742429482 1974-06-20 1974-06-20 Device for measuring and / or monitoring temperatures, levels and / or flow conditions of electrically conductive liquids of high specific heat Expired DE2429482C3 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE19742429482 DE2429482C3 (en) 1974-06-20 1974-06-20 Device for measuring and / or monitoring temperatures, levels and / or flow conditions of electrically conductive liquids of high specific heat
AT364075A AT338015B (en) 1974-06-20 1975-05-13 TEMPERATURE PROBE FOR USE IN A DEVICE FOR MEASURING AND / OR MONITORING TEMPERATURES, LEVELS AND / OR CONDITIONS OF ELECTRICALLY CONDUCTIVE LIQUIDS OF HIGH SPECIFIC WARMTH

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19742429482 DE2429482C3 (en) 1974-06-20 1974-06-20 Device for measuring and / or monitoring temperatures, levels and / or flow conditions of electrically conductive liquids of high specific heat

Publications (3)

Publication Number Publication Date
DE2429482A1 DE2429482A1 (en) 1976-01-02
DE2429482B2 true DE2429482B2 (en) 1978-05-03
DE2429482C3 DE2429482C3 (en) 1979-01-18

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ID=5918440

Family Applications (1)

Application Number Title Priority Date Filing Date
DE19742429482 Expired DE2429482C3 (en) 1974-06-20 1974-06-20 Device for measuring and / or monitoring temperatures, levels and / or flow conditions of electrically conductive liquids of high specific heat

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AT (1) AT338015B (en)
DE (1) DE2429482C3 (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3232333C2 (en) * 1982-08-31 1984-06-07 Siemens AG, 1000 Berlin und 8000 München Level sensor for liquids, in particular for determining the level of the brake fluid or the tank content in motor vehicles
FR2559797B1 (en) * 1984-02-17 1986-12-05 Esswein Sa DEVICE FOR CONTROLLING THE WATER LEVEL AND THE TEMPERATURE OF THE SAME IN A WASHING MACHINE
JPS6258721U (en) * 1985-10-02 1987-04-11
DE4003638A1 (en) * 1989-02-10 1990-08-23 Hiss Eckart Flow rate monitor using electric temp. difference measurement - has hollow cylindrical measuring pin containing temp. measuring elements and electric heating element
DE4116355C2 (en) * 1991-05-18 2000-05-18 Wilo Gmbh Sensor
DE102019111609A1 (en) * 2019-05-06 2020-11-12 Miele & Cie. Kg Temperature measuring probe and process for their manufacture

Also Published As

Publication number Publication date
AT338015B (en) 1977-07-25
ATA364075A (en) 1976-11-15
DE2429482A1 (en) 1976-01-02
DE2429482C3 (en) 1979-01-18

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