DE590289C - Electromagnetic strain or tension meter - Google Patents
Electromagnetic strain or tension meterInfo
- Publication number
- DE590289C DE590289C DENDAT590289D DE590289DD DE590289C DE 590289 C DE590289 C DE 590289C DE NDAT590289 D DENDAT590289 D DE NDAT590289D DE 590289D D DE590289D D DE 590289DD DE 590289 C DE590289 C DE 590289C
- Authority
- DE
- Germany
- Prior art keywords
- tension meter
- berlin
- coil
- electromagnetic strain
- air gap
- 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.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/16—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge
- G01B7/24—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge using change in magnetic properties
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
- G01L9/10—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in inductance, i.e. electric circuits therefor
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Bridges Or Land Bridges (AREA)
Description
Die Überwachung von Bauwerken bezüglich der in ihnen auftretenden Spannungen oder Dehnungen zur rechtzeitigen Erkennun von Bruch- oder Einsturzgefahr wie auch zur Kontrolle der theoretischen Rechnungen, auf Grund deren Bauwerke ausgeführt werden, ist deswegen ein schwieriges technisches Problem, weil häufig die gefährdeten Bauteile an vollständig unzugänglicher Stelle liegen. Ein wichtiges Beispiel hierfür sind die aus Beton gebauten Staudämme von Talsperren, in denen wegen der Verschiebungen des Untergrundes mit der Zeit nicht voraussehbare Verlagerungen eintreten können. Es sind elektromagnetische Meßgeräte bekannt, bei denen die zu messenden Verschiebungen direkt oder unter Zuhilfenahme einer übersetzung auf die Backen eines Luftspaltes wirken, der den im übrigen geschlossenen Eisenweg des magnetischen Kraftflusses eines elektrischen Solenoids unterbricht. Durch die Änderungen in der Breite des Luftspaltes werden Änderungen der Selbstinduktion des Solenoids hervorgerufen, die in bekannter Weise z.B. mit Hilfe einer wechselstromgespeisten Wheatstoneschen Brücke gemessen werden können. Bei den bekannten Meßgeräten dieser Art werden die Backen des Luftspaltes jedoch regelmäßig durch irgendwelche unter Reibung gegeneinander bewegliche Führungsteile in Abstand gehalten, die eine Verringerung der Meßgenauigkeit bewirken müssen. Bei reibenden Teilen läßt sich nämlich auch bei größter Sorgfalt der Herstellung kaum eine gewisse Ungleichmäßigkeit der Reibung vermeiden, die z. B. bei Schlittenführung zu kleinen Verkantungen Anlaß gibt, so daß der Apparat für feinste Messungen unbrauchbar wird. Im Gegensatz hierzu sind bei dem Meßapparat gemäß vorliegender Erfindung sämtliche Teile starr, ·ζ. Β. durch Löten oder Schweißen miteinander verbunden. Z. B. kann die Befestigung der einzelnen elektramagnetischen Teile auf einem in gewöhnlichem Sinne starren Träger stattfinden, während der Meßbereich des Apparats zugleich derart gewählt wird, daß die zu messenden Verschiebungen innerhalb der Elastizitätsgrenze des Trägers bleiben.The monitoring of structures with regard to the stresses occurring in them or stretching for the timely detection of the risk of breakage or collapse as well to check the theoretical calculations on the basis of which structures are being carried out, is therefore a difficult technical problem because the components at risk are often at risk lie in a completely inaccessible place. An important example of this are the concrete dams of dams in which because of the displacements of the subsoil, unpredictable shifts can occur over time. It electromagnetic measuring devices are known in which the displacements to be measured directly or with the help of a translation on the jaws of an air gap act, the otherwise closed iron path of the magnetic flux of a electric solenoid interrupts. Due to the changes in the width of the air gap changes in the self-induction of the solenoid are produced, which are known in Way, e.g. measured with the help of an AC-powered Wheatstone bridge can be. In the known measuring devices of this type, the jaws of the air gap are, however, regularly by any under friction against each other movable guide parts held at a distance, which cause a reduction in the measurement accuracy have to. In the case of rubbing parts, even with the greatest care, the Manufacture hardly avoid a certain unevenness of friction that z. B. gives cause for small canting during slide guidance, so that the apparatus for the finest Measurements becomes unusable. In contrast to this, in the case of the measuring apparatus according to the present invention all parts rigid, · ζ. Β. by soldering or Welding connected to each other. For example, the attachment of the individual electro-magnetic Parts take place on a rigid support in the usual sense, while the measuring range of the apparatus is selected in this way at the same time that the displacements to be measured remain within the elastic limit of the carrier.
Ein Ausführungsbeispiel für diese Bauart ist in der Figur dargestellt. Hier bedeutet G das zweckmäßig aus Stahl gefertigte starre Gehäuse, S ist das Solenoid, L der Luftspalt. Durch die überstehenden Stirnseiten des Gehäuses werden die Dehnungen des Betons auf das Gehäuse und damit auf den Luftspalt zwangsläufig übertragen, der sich bei Zusammendrückung verkleinert, bei Dehnungen erweitert. Wegen der außerordentlichen Verschiedenheit der Elastizitätsmoduln von Beton und Stahl treten von selbst nur so kleine Dehnungen auf, daß die Elastizitätsgrenze des Stahles nicht erreicht wird. Das Gehäuse kann beliebig stark ausgeführt werden, so daß es im Gegensatz zu den bekannten Meßapparaturen gegen gewöhnliche mechanische Beanspruchungen völlig unempfindlich wird. Dadurch werden Beschädigungen beim Einbau und Stampfen des Betons ausgeschlossen.An embodiment of this type is shown in the figure. Here G means the rigid housing made of steel, S is the solenoid, L is the air gap. Due to the protruding end faces of the housing, the expansion of the concrete is inevitably transferred to the housing and thus to the air gap, which is reduced when it is compressed and expanded when it is expanded. Because of the extraordinary difference in the modulus of elasticity of concrete and steel, the elongation is so small that the elastic limit of the steel is not reached. The housing can be made as thick as desired, so that, in contrast to the known measuring apparatus, it is completely insensitive to normal mechanical stresses. This prevents damage during the installation and tamping of the concrete.
Für das Wesen der Erfindung ist es nicht von Belang, auf welche Weise die Messung der Selbstinduktion erfolgt. Es empfiehlt sich, die Selbstinduktion des Meßinstruments in bekannter Weise in einer Wheatstoneschen Brücke mit einer meßbar veränderlichen Selbstinduktion zu vergleichen.For the essence of the invention it is not of concern in which way the measurement of self-induction is carried out. It is advisable, the self-induction of the measuring instrument in a known manner in a Wheatstone Compare bridge with a measurably variable self-induction.
Claims (1)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE590289T |
Publications (1)
Publication Number | Publication Date |
---|---|
DE590289C true DE590289C (en) | 1933-12-30 |
Family
ID=6572724
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DENDAT590289D Expired DE590289C (en) | Electromagnetic strain or tension meter |
Country Status (1)
Country | Link |
---|---|
DE (1) | DE590289C (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1025645B (en) * | 1953-01-21 | 1958-03-06 | Wacker Hermann | Electromagnetic device for measuring mechanical forces in statically or dynamically stressed components |
DE1062032B (en) * | 1957-05-06 | 1959-07-23 | Veruschacht Vereinigte Unterta | Process for the determination and measurement of stresses and / or deformations in mountain and building structures |
DE3735657A1 (en) * | 1986-10-21 | 1988-05-19 | Kohn Dietmar | Device for measuring the extent of a solid body |
DE4001953A1 (en) * | 1990-01-24 | 1991-07-25 | Giese Erhard | Pressure sensor esp. for industrial processing and large temp., range - has pressure-distance transducer and distance sensor and mounting tube operating distance ring |
-
0
- DE DENDAT590289D patent/DE590289C/en not_active Expired
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1025645B (en) * | 1953-01-21 | 1958-03-06 | Wacker Hermann | Electromagnetic device for measuring mechanical forces in statically or dynamically stressed components |
DE1062032B (en) * | 1957-05-06 | 1959-07-23 | Veruschacht Vereinigte Unterta | Process for the determination and measurement of stresses and / or deformations in mountain and building structures |
DE3735657A1 (en) * | 1986-10-21 | 1988-05-19 | Kohn Dietmar | Device for measuring the extent of a solid body |
DE4001953A1 (en) * | 1990-01-24 | 1991-07-25 | Giese Erhard | Pressure sensor esp. for industrial processing and large temp., range - has pressure-distance transducer and distance sensor and mounting tube operating distance ring |
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