GB2042168A - Optical pick-up and transmission of a parameter being measured - Google Patents
Optical pick-up and transmission of a parameter being measured Download PDFInfo
- Publication number
- GB2042168A GB2042168A GB8002950A GB8002950A GB2042168A GB 2042168 A GB2042168 A GB 2042168A GB 8002950 A GB8002950 A GB 8002950A GB 8002950 A GB8002950 A GB 8002950A GB 2042168 A GB2042168 A GB 2042168A
- Authority
- GB
- United Kingdom
- Prior art keywords
- light
- light guide
- figures
- transmission
- fibre
- 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.)
- Withdrawn
Links
- 230000005540 biological transmission Effects 0.000 title claims abstract description 35
- 230000003287 optical effect Effects 0.000 title claims abstract description 20
- 238000000034 method Methods 0.000 claims abstract description 14
- 230000033001 locomotion Effects 0.000 claims abstract description 13
- 239000004973 liquid crystal related substance Substances 0.000 claims abstract description 9
- 239000000835 fiber Substances 0.000 claims abstract description 4
- 239000012528 membrane Substances 0.000 claims description 13
- 239000002775 capsule Substances 0.000 claims description 6
- 230000008878 coupling Effects 0.000 claims description 5
- 238000010168 coupling process Methods 0.000 claims description 5
- 238000005859 coupling reaction Methods 0.000 claims description 5
- 238000005259 measurement Methods 0.000 claims description 5
- 230000002441 reversible effect Effects 0.000 claims description 3
- 239000013307 optical fiber Substances 0.000 claims description 2
- 239000007787 solid Substances 0.000 claims 2
- 230000001419 dependent effect Effects 0.000 claims 1
- 229910001285 shape-memory alloy Inorganic materials 0.000 claims 1
- 238000012545 processing Methods 0.000 abstract description 3
- 230000005855 radiation Effects 0.000 abstract 1
- 210000004027 cell Anatomy 0.000 description 17
- 210000002858 crystal cell Anatomy 0.000 description 4
- 239000011521 glass Substances 0.000 description 4
- 230000001133 acceleration Effects 0.000 description 3
- 238000012423 maintenance Methods 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 2
- 238000009529 body temperature measurement Methods 0.000 description 2
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 2
- 229910052753 mercury Inorganic materials 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 1
- 238000005352 clarification Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 239000005394 sealing glass Substances 0.000 description 1
- 229910000679 solder Inorganic materials 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- 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
- G01L9/0033—Transmitting or indicating the displacement of bellows by electric, electromechanical, magnetic, or electromagnetic means
- G01L9/0039—Transmitting or indicating the displacement of bellows by electric, electromechanical, magnetic, or electromagnetic means using photoelectric means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/28—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with deflection of beams of light, e.g. for direct optical indication
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K1/00—Details of thermometers not specially adapted for particular types of thermometer
- G01K1/02—Means for indicating or recording specially adapted for thermometers
- G01K1/024—Means for indicating or recording specially adapted for thermometers for remote indication
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Measuring Fluid Pressure (AREA)
- Liquid Crystal (AREA)
Abstract
Method and device for the purely passive, fibre-optic pick-up and transmission of a not-directly accessible measured value of a temperature (Figures 1, 2 and 3), a pressure (Figures 4, 5 and 6) or a motion (Figures 7 and 8) by discretely changing the light transmitting capacity of an optical path, through which a light beam has to pass. The light is guided in one or several light guides and the corresponding signal being evaluated directly or via a data processing system. Some embodiments (Figures 1, 24) containing a plurality of light guides T1, T2, T3 and T4 employing a test object 3 that obstructs one or more of the light guides radiation emitting or receiving ends in dependence upon a physical variable (the Figures 4 and 6 embodiments also using a mirror 4). Other embodiments (Figures 5 and 6) employ a reflective surface that reflects light back to fibre ends in dependence upon a physical variable. A pair of embodiments (Figures 7 and 8) employ a motional element that has a regular pattern on it and the light guides detect the changes in the pattern as the element moves past the guides ends. In a further embodiment (Figure 3) the example shown, a liquid crystal 10 exhibits an abrupt change in transmission between an incoming light guide 7 and outgoing light guide 7 at a predetermined temperature. <IMAGE>
Description
SPECiFICATION
Optical pick-up and transmission of a parameter being measured
This invention relates to a method and device for the optical pick-up of a parameter being measured.
The transmission of measured physical values via fibre-optic cables is known from numerous publications. In particular, methods and devices have already been proposed for transmitting a signal with the aid of fibre cables (light guides) from a point of high electric potential to earth potential and reverse (for example J.J.L. Weaver and A.M. Eccles, "Optoelectric Control in Megawatt Electrical Power
Systems", Proceedings, Electro-optics 71, Brighton,
England 1971).
In this connection, however, the assumption is always made that the measuring sensors should be active elements which, for converting the measured signal into an optical signal, require an electronic circuit which must be supplied with power. Now this power supply of a measuring sensor at high potential (for example in a high-tension switch at 100 kV), however, presents a very costly problem. It has certainly already been proposed to decouple the energy required for the sensors from the high tension circuit, but since such control sensors have to function continuously, that is also in the absence of the high-tension, a storage system with rectification and battery, and all its maintenance problems, must be coupled in for this purpose. As an alternative there are proposals to couple the energy in mechanically via a vibrating, insulating rod.
Methods for optically measuring currents in hightension networks by using a laser and an optical flint sensor have already been suggested (for example
Andre A. Jaecklin, "Measuring Current at Extra-High
Voltage", Laser Focus Magazine, May 1970, Advanced Technology Publications, Inc. Newtonville,
Mass. 02160).
In accordance with the present invention, there is provided a method for optical pick-up and transmission of a temperature, a pressure or a motion being measured, in which a measurement transducer controls at least one light beam, guided in a fibre-optic light guide, by changing, in steps, the light transmission along an optical path of a transmission cell which is coupled to the transducer in a purely passive manner.
Also in accordance with the present invention, there is provided a device for carrying out said method, comprising a passive measurement transducer coupled into an optical transmission cell for at least one light beam, and at least one light-guide optical fibre coupled into the transmission cell. Thus, for picking up temperature, pressure and the like no active components, which must be supplied with some form of energy, are used at all, but only exclusively passive measuring sensors, and that the transmission is carried out purely optically with the aid of light guides. The signal obtained can be utilised directly or fed into an electronic data processing system.
In principle, the value to be measured can be monitored continuously and non-intermittently. Devices, as a rule opto-mechanical, designed in accordance with this principle, however, still require a high degree of maintenance. In practice one is mostly not interested in a continuous pick up of measured values, however, but merely in the determination of several discrete points or critical threshold values.
Devices which serve this purpose, and described below, excel by operating steadily and without requiring maintenance over long periods. The measured value can basically be transmitted via two separate light guides (input and output) which are located either on different sides or on the same side of the transmission cell. In the latter case an additional reflector (mirror) is provided. However, for the light beam arriving from the light source and departing from the transmission cell the same light guide can be used by coupling the reflected part of the light out of the light guide in the vicinity of the light source and supplying into the measuring device or the data processing system.In this way indiscrete, reversible and hysteresis-free changes in the optical transmission in the cell can be used to determine discrete values for temperatures, pressure, geometric position, course of motion, speed, acceleration and the like of a component. For picking up the magnitude and direction and the derived parameters of a movement, strip patterns are particularly suitable which are scanned with phase-shifted light signals, as are phase-shifted or multi-line strip patterns.
Embodiments of the invention will now be described, by way of examples only, with reference to the accompanying drawings, in which:
Figure 1 shows a transmission cell for temperature measurement by means of a column type thermometer;
Figure 2 shows a transmission cell for temperature measurement by means of a bimetallic strip;
Figure 3 is a longitudinal section through a transmission cell for picking up a measured temper aturevalue by means of a liquid crystal cell;
Figure 4 shows the principle of measuring pressure by means of a barometer capsule;
Figure 5 shows the principle of measuring pressure by means of a curved, reflecting membrane;
Figure 6 is a longitudinal section through a transmission cell for measuring pressure by means of a plane, reflecting membrane;;
Figure 7comprises a front elevation and a plan view of a motional element with a one-line strip pattern, and
Figure 8 comprises a front elevation and a plan view of a motional element with a multi-line strip pattern.
In Figure 1 a transmission cell used for measuring temperature is shown diagrammatically. The light guides 1, consisting of one glass fibre each and in each case corresponding to a temperature T1....T4, are arranged vertically with respect to the glass bulb 2 of a column type thermometer and terminate flush with the surface of the latter. Behind the glass bulb 2, provided with a mercury filling 3, of the thermometer a reflector 4, shown in section, is located which reflects the light emerging from the light guides 1 into those guides which are not blocked by the mercury column.
Figure 2 shows a transmission cell, also used for measuring temperature, which utilises a bimetallic strip 6. The light guides 5, shown in cross-section and here constructed as a fibre-optical ribbon cable, are arranged with their longitudinal axis vertically with respect to the plane of a reflector 4 and end at a certain distance from the latter. In the interspace formed by this arrangement a bimetallic strip 6 can move freely, in accordance with the fluctuations in temperature, in a plane (here the plane of the drawing) parallel to the plane of the reflector. The end positions of the bimetallic strip which correspond to the extreme temperatures are indicated in the Figure by curved dashed lines.
Figure 3 shows a transmission cell for picking up a measured temperature value, built up on the principle of a liquid crystal cell. In the glass support 9 both an incoming light guide 7 and an outgoing light guide 8 are held. Between them a cell is located which consists of a front cover plate 11 and a rear cover plate 12 and the hermetically sealing glass solder 13. 11 and 12 consists of glass or any other suitable ceramic translucent material. The interspace is filled by the liquid crystal 10, a substance which changes its optical transmission properties in steps as a function of temperature. Below the clarification point TK corresponding to the temperature to be measured, the optical transmitting capacity greatly decreases due to the incidence of opaqueness and diffuse scattering.
In Figure 4 the principle of measuring a pressure by means of a barometer capsule is shown diagrammatically. Basically, the construction of the individual elements is similarto that of the Figure 1.
Opposite to the light guides 1 arranged in one plane a reflector4 is located the plane of which is at right angles to that of the light guides. In the interspace an indicating rod 15 is located which rests on the barometer capsule 14 and can move vertically with respect to the longitudinal axis of the light guide 1 in proportion to the pressure to be measured.
Figure 5 shows diagrammatically the principle of measuring a pressure by means of a curved, reflecting membrane. The capsule 16 filled with a compressible medium 18 (for example air) is provided with a (for example curved) membrane 17 with a reflecting surface. The light guides 7 and 8, one of which is used for the incoming light beam and the other one of which is used for the outgoing light beam, end at a small distance from the membrane 17. The expansion of the membrane 17 as a result of fluctuations in pressure produces changes in the light coupling conditions and the reflection, which permits the pressure to be monitored continuously.
Figure 6 shows the longitudinal section through a transmission cell for measuring a pressure continuously by means of a plane, reflecting membrane.
In a two-part housing 19 a flexible membrane 17, reflecting on its outside, is clamped. The membrane 17 and the one half of the housing 19 form a chamber, held at a certain reference pressure P containing a compressible medium 18. The other half of the housing 19 contains the light guides 7 and 8forthe incoming and outgoing beam which are arranged with their longitudinal axis vertically with respect to the plane of the membrane 17 and which end directly in front of the latter. In addition, the second half of the housing is provided with an opening 20 for pressure measuring. Depending on the prevailing external pressure, the membrane 17 is deformed and supplies a measure for the light coupling between the guide 7 and 8. Such cells are suitable for static and dynamic pressure measuring with a time resolution down to approximately 1 ms.
In Figure 7 the front elevation and the plan view of a motional element with a one-line strip pattern is shown diagrammatically. Such devices permit the determination and monitoring of the position and course of motion of a component. The motional element designated by 21 can shift in its longitudinal direction in accordance with the indicating arrows.
For picking up its instantaneous position it is provided with a one-line pattern 22 which contains alternating consecutive absorption and reflection strips. A pair of light guides 23 is arranged vertically with respect to the plane of this pattern in a support 24. To the individual fibres of the pair of light guides, optical signals are applied which are phase shifted by 90 each. For this purpose the two light guides are arranged in a plane containing the direction of movement of the element 21. With such an arrangement it is possible to determine the position, direction of movement and speed, and the derived magnitudes of acceleration, change in acceleration and the like, electronically. The accuracy of resolution can here be selected within wide limits by selecting the width of the strips.
Figure 8 shows a similar arrangement as Figure 7 but with a motional element 21 which on one longitudinal side is provided with a multi-line strip pattern 25. In this arrangement the absorption and reflection strips have a different width, seen in the direction of movement, for example the relative width 1, 2, 4, 8, built up in accordance with a binary code. Accordingly, the corresponding light guide ribbon cable 26 arranged with four guides and located opposite and fixed in the support 24, optically scans the four-line strip pattern. In the present example, 4 light guides allow the transmission of 24 = 16 positions in binary code.Naturally, in this case the plane of the ribbon cable 26 must be located at right angles to the direction of movement (indicated by arrows) of the motional element 21 so that each guide "reads" the corresponding line located opposite to it of the pattern 25. Such a device can be used to specify the exact position of the element 21 directly in digital form, a so-called Gray code (change of signal with time only in one channel in each case) being used advantageously for avoiding read-out errors.
The invention is not restricted to the illustrative embodiments shown in the Figures. In particular, the transmission cell according to Figure 3 can be constructed in such a manner that both the incoming and the outgoing light guides are located on the same side or that only a single light guide is provided for both paths and behind the liquid crystal cell an additional reflectorsimilarto Figure 1 is mounted. A similar consideration applies to the pressure measuring arrangement according to Figure 6 in that here, too, a single light guide can be used in an analogous manner. In addition, the liquid crystal cell according to Figure 3 can be replaced by a solid-state body which changes its optical properties in steps as a function of temperature. The method according to the invention, and the corresponding devices, make it possible to pick up physical values to be measured, which are not easily accessible due to environmental conditions, in a simple and largely interference-free and reliable manner whilst avoiding complicated arrangements and energydependent devices at the place of measurement. The method can be used particularly for the transmission of measured values from devices under high tension to an evaluating device at a different potential (e.g.
earth potential).
Claims (16)
1. Method for the optical pick-up and transmission of a temperature, a pressure or a motion being measured, in which a measurement transducer controls at least one light beam, guided in a fibre-optic light guide, by changing, in steps, the light transmission along an optical path of a transmission cell which is coupled to the transducer in a purely passive manner.
2. Method according to claim 1, in which different light guides are used for guiding the light beam from a light source to the transmission cell and from the latter to the receiver.
3. Method according to claim 1, in which the same light guide is used for guiding the light beam from a light source to the transmission cell and from the latter to the receiver, the light beam being reflected in the transmission cell and the reflected portion of the light beam being coupled out of the light guide at the location of the light source.
4. Method according to claim 1, in which for picking up a motion a motional element is provided which possesses a one- or multi-line strip pattern and the course of the motion is transmitted in the form of pulses via lightguides and is evaluated electronically.
5. Device for carrying out the method according to claim 1, comprising a passive measurement transducer, coupled into an optical transmission cell for at least one light beam, and at least one light-guide optical fibre coupled into the transmission cell.
6. Device according to claim 5, in which a column type thermometer is provided at its rear with a reflector, a light guide being provided for each interval of temperature.
7. Device according to claim 5, in which a temperature-dependent element in the form of a bimetallic strip or of a body made of a memory alloy and with a reflector on its reverse side is provided, with a fibre-ribbon cable containing a multiplicity of light guides arranged side by side or on top of one another.
8. Device according to claim 5, in which a liquid crystal or solid state body is provided, which alters its optical properties in steps as a function of temperature, together with an incoming and outgoing light guide.
9. Device according to claim 8, in which the incoming and the outgoing light guides are located at the same side of the liquid crystal or solid state body, with a reflector mounted on the other side.
10. Device according to claim 5, in which a liquid crystal is provided, which changes its optical properties in steps as a function of temperature, with a single light guide and a reflector, and with, at the end of the light guide at which a light source is situated, a coupling unit mounted for determining the light reflected back into the fibre.
11. Device according to claim 5, in which a barometer or a manometer possessing a mechanical indicating device projecting into the path of the light beam is provided, with a multiplicity of light guides arranged on top of one another in the direction of movement of the indicating device.
12. Device according to claim 5, in which a capsule containing a compressible medium is provided, having on one side a curved or plane reflecting membrane, together with at least two light guides.
13. Device according to claim 5, in which a capsule containing a compressible medium is provided, having on one side a curved or plane membrane, together with a single light guide and with, at the end of the light guide at which a light source is situated, a coupling unit mounted for determining the light reflected back into the fibre.
14. Device according to claim 5, in which high tension is applied to the optical transmission cell, and for evaluating the measured value a device is provided to which a different potential or earth potential is applied.
15. A method according to claim 1 and substantially as herein described.
16. Device according to claim 5 and substantially as herein described with reference to any one of
Figures 1 to 8 of the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH92279 | 1979-01-31 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2042168A true GB2042168A (en) | 1980-09-17 |
Family
ID=4198285
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8002950A Withdrawn GB2042168A (en) | 1979-01-31 | 1980-01-29 | Optical pick-up and transmission of a parameter being measured |
Country Status (2)
| Country | Link |
|---|---|
| DE (1) | DE2906280A1 (en) |
| GB (1) | GB2042168A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2514917A1 (en) * | 1981-10-19 | 1983-04-22 | Seeb Sarl | Optical fibre position detector - has several fibres abutting partially reflecting tracks of differing lengths such that reflected light signal indicate movement of tracks |
| EP0115025A3 (en) * | 1982-12-23 | 1984-12-12 | Wolfgang Dr. Ruhrmann | Optical sensor |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4427881A (en) * | 1981-03-09 | 1984-01-24 | Siemens Corporation | Sensor device for measuring a physical parameter |
| DE3618230A1 (en) * | 1986-05-30 | 1987-12-03 | Meyer Fa Rud Otto | Optical measurement value pick up |
| DE4312530A1 (en) * | 1993-04-16 | 1994-10-20 | Cytech Biomedical Inc | Microwave temperature sensor for liquids and method for determining and method for setting a temperature of a liquid by means of microwave energy |
| DE102016222002A1 (en) * | 2016-11-09 | 2018-05-09 | Bayerische Motoren Werke Aktiengesellschaft | In-situ temperature measurement of an energy storage cell |
-
1979
- 1979-02-19 DE DE19792906280 patent/DE2906280A1/en not_active Withdrawn
-
1980
- 1980-01-29 GB GB8002950A patent/GB2042168A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2514917A1 (en) * | 1981-10-19 | 1983-04-22 | Seeb Sarl | Optical fibre position detector - has several fibres abutting partially reflecting tracks of differing lengths such that reflected light signal indicate movement of tracks |
| EP0115025A3 (en) * | 1982-12-23 | 1984-12-12 | Wolfgang Dr. Ruhrmann | Optical sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| DE2906280A1 (en) | 1980-08-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |