WO1994029702A1 - Nadelsonde zur messung der leitfähigkeit in flüssigkeiten oder mehrphasengemischen - Google Patents
Nadelsonde zur messung der leitfähigkeit in flüssigkeiten oder mehrphasengemischen Download PDFInfo
- Publication number
- WO1994029702A1 WO1994029702A1 PCT/DE1994/000645 DE9400645W WO9429702A1 WO 1994029702 A1 WO1994029702 A1 WO 1994029702A1 DE 9400645 W DE9400645 W DE 9400645W WO 9429702 A1 WO9429702 A1 WO 9429702A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- probe
- needle probe
- measuring
- liquids
- needle
- Prior art date
Links
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
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/06—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a liquid
- G01N27/07—Construction of measuring vessels; Electrodes therefor
Definitions
- the invention relates to a stable needle probe for measuring the electrical conductivity of liquids or multiphase mixtures, in particular for use in process and power plant technology, the electrical conductivity predominantly as a measure of further physical or chemical properties (for example temperature, concentration) of the liquid or is used as an indicator of the phase of a multiphase mixture currently in contact with the probe.
- the probes described consisting essentially of the wire electrode located within an insulating tube and possibly protected by an enveloping support tube, are immersed through the vessel wall into the medium to be measured or the multiphase mixture.
- the conductivity is measured between the inner electrode of the probe and an electrically conductive counter electrode, which can be formed, for example, by the electrically conductive walls of the vessel of the medium to be examined.
- the electrical signal is taken from the rear end of the probe and further processed electrically.
- REPLACEMENT LEAF to provide an electrically insulating structural part.
- multi-phase mixtures there is also interest in a high local resolution of the measuring arrangement and therefore in an electrode surface which is only effective in a punctiform manner.
- the insulation of the inner electrode is therefore extended to the tip of the electrode as a tube and is often mechanically protected by an additional metallic carrier tube.
- This metallic support tube of the needle probe can also be used as the counter electrode of the measuring circuit.
- the insulating tube is often designed in the form of two tubes made of different materials arranged one behind the other. The front pipe section then takes the pressure seal alone.
- the design-related sealing points of the needle probe which can be implemented, for example, as brazing, consist first of all in the connection between the support tube and the insulation tube and in the connection between the insulation tube and the inner electrode.
- the probe as such must be inserted pressure-tight into the vessel wall.
- a version with two or more electrodes allows the additional speed measurement of bubbles or of liquid plugs in multiphase flows.
- Such a two-wire arrangement is specified in the article [Xie et al .: "Behavior of Bubbles at Gas Blowing into Liquid Wood's Metal” (ISIJ International, Vol. 32 (1992), No. 1, pp. 66-75)].
- the further expansion of a conductivity probe with the aim of additional temperature measurement is specified in DE-PS 968548.
- two sensor elements which are suitable for detecting one of the physical quantities mentioned, are constructively combined in such a way that the sensor acts externally like a single sensor.
- the design of needle probes for process and power plant technology is significantly influenced by the required pressure tightness.
- the technologies currently used e.g. sintering, soldering, welding or melting
- use high temperatures because the connection to be created must withstand even high temperatures.
- the high environmental stresses described above greatly reduce the stability of the needle probes.
- Decisive technological weak points are the different temperature coefficients of the pressure-tightly bonded materials, which means that temperature-related mechanical stresses are generated in the materials during probe manufacture, but also during subsequent practical use, which initially lead to crack formation
- needle probes For applications in process and power plant technology, the service life of needle probes is therefore limited. In spite of the otherwise favorable metrological properties, needle probes are therefore usually only suitable for shorter-duration experiments, but not for frequently requested long-term monitoring.
- the object of the invention is to create a needle probe for extreme environmental parameters and with high stability.
- the solution according to the invention uses the principle in the manufacture of the needle probe to remove as far as possible all the technological processing and problematic constructive designs which reduce the later reliability, such as the gastight and pressure-tight material composite, from the particularly heavily used probe tip and to less stressed probe parts, especially the rear one , end protruding from the measuring vessel. Above all, this means operating the probe unsealed at the front. Suitable design measures must then be taken to ensure that, in the event of a probe defect, no leakage can act on the outside even under high pressure conditions of the medium; A harmful probe defect can also be ruled out if appropriate material technology is used.
- the elimination of the pressure-tight electrode bushing at the tip of the probe enables the use of flexible materials to build a mechanically flexible probe that can be easily adapted to the special geometries of the vessel or other internals within the vessel carrying the medium to be measured.
- the arrangement of the pressure-tight closure of this tube at the outer end of the needle probe can achieve an additional effect in terms of a safety encapsulation of the probe with regard to external mechanical stress and thus any leakage that may occur.
- the full operating pressure of the medium under investigation is available at its rear pressure-sealed part.
- the temperature at the rear end of the needle probe is significantly reduced and can already be close to the ambient temperature.
- commercially available transducers for measuring the system pressure which are limited in the operating temperature range compared to the system temperature, can be used at the rear end of the probe, such as pressure transducers based on a flexible membrane with a strain gauge bridge.
- the inner electrode can be used simultaneously for electrical temperature measurement. If the temperature-sensitive part of the inner electrode is essentially concentrated in the front end of the probe, for example in the case of a jacket thermocouple, the system temperature can then be detected. In addition, the chemical concentration of the medium can also be determined from the temperature and the conductivity of the medium, the actual measured variable of the needle probe.
- the inner electrode (1) consists of an electrically conductive material, e.g. a precious metal or conductive ceramic.
- This inner electrode (1) lies loosely in an insulating tube (2), which can be formed, for example, from electrically insulating ceramic.
- the insulation can e.g. B. consist of a Teflon coating. While the front end of the probe is immersed in the liquid to be measured and the actual measuring effect occurs there, the pressure-tight electrode bushing is located at the rear end of the needle probe. The temperature and vibration stress at this point of the needle probe are significantly reduced compared to the stresses at the front tip.
- the lower temperature load also allows the selection of far more materials and technologies for pressure sealing than would be possible at the front probe tip.
- the additionally attachable (eg metallic) support tube (3) for the probe solves two tasks at the same time. It is used for the direct protection of the probe against mechanical hazards that can occur on either side of the vessel wall.
- the support tube also pressure-encapsulates the needle probe outside the medium in the event of a defect in the insulating tube. The pressure encapsulation can also be assigned a device for connecting and leading out the measuring cable at the rear end of the needle probe.
- a cooling body (4) provides an additional temperature gradient along the probe between its contact point with the mostly hot vessel wall and the temperature-sensitive electrode bushing at the rear end of the probe. It can be attached both to the carrier tube and - in the case of a version without a carrier tube - directly to the insulating tube.
- the support tube (3) contains individual openings (5) in the area which is immersed in the medium to be measured. The medium which has penetrated between the carrier and insulating tube and which may evaporate in the event of a pressure drop can escape laterally through these openings. In this way, a large part of the steam which may be generated is directed past the tip of the probe and a temporarily occurring measurement error is considerably reduced.
- both the pressure-tight electrode bushing and the connection of the support tube (3) to the insulating tube (2) are designed to be more stable than in the case of known probe designs, since these two connections are not exposed to flow-induced vibrations and shocks or extreme temperatures of the medium . Furthermore, the arrangement of the critical material connections at the rear end and the possible use of other materials there can reduce corrosive influences on these connection points.
- a pressure transducer can be installed in the needle probe outside the vessel that contains the medium to be measured in such a way that
- the inner electrode (1) is designed as an additional temperature-sensitive element, for example as a thermocouple. Because of the high pressure and temperature loads at the tip of the probe and its small geometric dimensions, only solutions are possible that allow an extremely compact structure. Joining and connection technologies should be avoided as far as possible. A solution to this problem is given with the integral sensor element proposed above, which is suitable as a structurally unsolvable composite for the simultaneous measurement of two physical quantities.
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)
- Measurement Of Resistance Or Impedance (AREA)
- Testing Resistance To Weather, Investigating Materials By Mechanical Methods (AREA)
- Testing Or Calibration Of Command Recording Devices (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE4493861D DE4493861D2 (de) | 1993-06-16 | 1994-06-09 | Nadelsonde zur Messung der Leitfähigkeit in Flüssigkeiten oder Mehrphasengemischen |
DE4493861A DE4493861C1 (de) | 1993-06-16 | 1994-06-09 | Nadelsonde zur Messung der Leitfähigkeit in Flüssigkeiten oder Mehrphasengemischen |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DEP4320116.4 | 1993-06-16 | ||
DE19934320116 DE4320116A1 (de) | 1993-06-16 | 1993-06-16 | Nadelsonde zur Messung der Leitfähigkeit in Flüssigkeiten oder Mehrphasengemischen |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1994029702A1 true WO1994029702A1 (de) | 1994-12-22 |
Family
ID=6490567
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/DE1994/000645 WO1994029702A1 (de) | 1993-06-16 | 1994-06-09 | Nadelsonde zur messung der leitfähigkeit in flüssigkeiten oder mehrphasengemischen |
Country Status (4)
Country | Link |
---|---|
CZ (1) | CZ287276B6 (de) |
DE (2) | DE4320116A1 (de) |
RU (1) | RU2125722C1 (de) |
WO (1) | WO1994029702A1 (de) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102005046662B3 (de) * | 2005-09-29 | 2007-03-22 | Forschungszentrum Rossendorf E.V. | Anordnung zur Messung der lokalen elektrischen Impedanz und der Temperatur in Fluiden |
DE102012102870B4 (de) | 2012-04-02 | 2013-12-24 | Helmholtz-Zentrum Dresden - Rossendorf E.V. | Nadelsonde zur Untersuchung von Mehrphasenströmungen und deren Verwendung |
DE102019129434A1 (de) * | 2019-10-31 | 2021-05-06 | AVX/KUMATEC Hydrogen GmbH & Co. KG | Messeinrichtung zum Messen der Leitfähigkeit von Medien in einer Hochdruckumgebung und Anordnung mit einer Messeinrichtung |
CN112649039B (zh) * | 2020-11-06 | 2023-06-27 | 重庆大学 | 一种用于高温高压两相流探测的多探头电导探针及其制造方法 |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3906354A (en) * | 1973-10-09 | 1975-09-16 | Westinghouse Electric Corp | Standard conductivity cell for measurement of sea water salinity and temperature |
GB2196202A (en) * | 1987-09-22 | 1988-04-20 | Panbourne Ltd | A monitoring device |
US4804936A (en) * | 1986-01-13 | 1989-02-14 | Saler Electronic Systems, Inc. | Liquid selective automatic bilge pump control |
WO1989009396A1 (en) * | 1988-03-25 | 1989-10-05 | Beta Sensor Ab | Apparatus for measuring parameters in a moving fluid and a method of making a cell therefor |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE968548C (de) * | 1944-05-16 | 1958-03-06 | Wilhelm Schmidts | Messwertgeber zur Leitfaehigkeitsmessung von fluessigen Elektrolyten |
DE3816458A1 (de) * | 1988-05-13 | 1989-12-21 | Josowicz Mira | Ultramikroelektrode, verfahren zu deren herstellung und ihre verwendung |
-
1993
- 1993-06-16 DE DE19934320116 patent/DE4320116A1/de not_active Withdrawn
-
1994
- 1994-06-09 DE DE4493861A patent/DE4493861C1/de not_active Expired - Fee Related
- 1994-06-09 CZ CZ19953333A patent/CZ287276B6/cs not_active IP Right Cessation
- 1994-06-09 RU RU96101181A patent/RU2125722C1/ru not_active IP Right Cessation
- 1994-06-09 WO PCT/DE1994/000645 patent/WO1994029702A1/de active IP Right Grant
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3906354A (en) * | 1973-10-09 | 1975-09-16 | Westinghouse Electric Corp | Standard conductivity cell for measurement of sea water salinity and temperature |
US4804936A (en) * | 1986-01-13 | 1989-02-14 | Saler Electronic Systems, Inc. | Liquid selective automatic bilge pump control |
GB2196202A (en) * | 1987-09-22 | 1988-04-20 | Panbourne Ltd | A monitoring device |
WO1989009396A1 (en) * | 1988-03-25 | 1989-10-05 | Beta Sensor Ab | Apparatus for measuring parameters in a moving fluid and a method of making a cell therefor |
Also Published As
Publication number | Publication date |
---|---|
CZ287276B6 (en) | 2000-10-11 |
DE4320116A1 (de) | 1994-12-22 |
DE4493861C1 (de) | 2003-04-03 |
CZ333395A3 (en) | 1996-06-12 |
RU2125722C1 (ru) | 1999-01-27 |
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