WO1987005103A1 - Fibre-optic thermometer or temperature alarm device - Google Patents
Fibre-optic thermometer or temperature alarm device Download PDFInfo
- Publication number
- WO1987005103A1 WO1987005103A1 PCT/FI1987/000024 FI8700024W WO8705103A1 WO 1987005103 A1 WO1987005103 A1 WO 1987005103A1 FI 8700024 W FI8700024 W FI 8700024W WO 8705103 A1 WO8705103 A1 WO 8705103A1
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- Prior art keywords
- fibre
- light
- substance
- optic
- threshold temperature
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
- G01K11/12—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in colour, translucency or reflectance
- G01K11/18—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in colour, translucency or reflectance of materials which change translucency
Definitions
- the present invention concerns a therrroneter or temperature alarm device making use of fibre optics.
- threshold alarm can be obtained from a conventional electronic thermometer by providing electronic circuits for threshold detection so that an alarm is actuated if the preset temperature is surpassed.
- thermometer there are however various situations in which one would prefer to forgo the use of a so-called electronic thermometer because such instruments as a rule contain an electrically conductive measuring pick-up, or sensor, to which a voltage has been applied.
- Typical objects of measurement where this consideration is relevant are, for instance, warehouses containing readily inflammable chemicals, e.g. oil tanks and cisterns, powder stores, etc.
- the electrically conductive pick-up leads may give rise to sparking, and they may for instance carry lightning into the storage space, with disastrous results.
- thermometers thermometers
- measuring instruments such as thermometers
- fibre optics have the inherent advantage that the optic fibre itself is an insulator and thus cannot cause any harmful electrical phenomena, such as short circuits or sparking, which might cause dangerous situations in an environment susceptible to explosion.
- fibre-optic thermometers of present art have turned out to be rather complicated and expensive, and this has limited their use.
- thermometers employing conventional galvanic technology, such as thermocouples, thermistors or NTC and PIC resistance elements, offer a rather inexpensive and reliable solution to surveillance problems as long as there is no apprehension rega-rding risk of fire or explosion. It is possible especially with PIC and NTC resistors to implement a temperature detection which is specifically of the alarm type because the resistance of these resistors changes most powerfully as a function of temperature in various temperature ranges.
- Ihe fibre-optic thermometers known at present are based on the principle that light is carried with an optic fibre to a measuring cell and the material in this cell reacts in one way or another to the temperature so that the change of temperature can be observed by optical means.
- liquid crystals are dependent on temperature in such a way that it is possible to construct thermometers using liquid crystals.
- Liquid crystals cause a kind of interference phencmena in thin films so that the colour of the liquid crystal film appears to change as a function of temperature in desired manner.
- a type of paint ccarposed of liquid crystals is known which can be used to coat those objects which are of interest, and one may then observe the changing colour by those means which fibre optics afford. It has to be noted, hcwever, that liquid crystal materials have no particularly long life span: in a way, they are decomposed as they age.
- a fibre-optic thermometer differing frcm that which has been described above and which can be used to observe the temperature in a given space and to obtain alarm if the temperature rises over a given critical value.
- These critical values depend on the material that has been placed in the sensor itself and they are therefore highly reliable and reproducible because in their case no thought need be given to the potential creep of electronically set threshold values.
- the threshold values can be derived from the material parameters of the sensor material itself.
- the pick-ups to be presented here are furthermore highly reliable, simple and inexpensive, as will become apparent later on.
- the following situation shall be considered in which e.g. in a test tube of glass has been placed snow.
- a narrow laser light beam is directed on this test tube, it will be found that no light can pass through the test tube: the light is all scattered frcm the sncw surface. Snew is white, a well-known fact, because it scatters nearly all of the incident light. But if the contents of the test tube are warmed so that the sncw therein melts, all light can pass through and hardly anything is scattered back frcm the surface of the test tube.
- the temperature has definitely increased to be higher than the melting point of sncw, i.e., 0°C.
- a separate sensor housing is used, which is filled with a material of the above-described kind and the optical properties of which are monitored with optic fibres.
- Optic fibre transmitters and receivers are known in the art in themselves, but all the same they constitute an important component part in the present invention.
- Said sensor housing may be filled with a material which melts and turns transparent above a certain temperature which is characteristic for the material in question but is solid and scatters back a great part of the light incident on it, at temperatures below said melting point.
- Stearine may be mentioned as an example. Below its melting point stearine is white and kind of milky, and it scatters back all light. When it melts, stearine turns transparent and clear like water and transmits all light.
- Stearine in solid state contains microcrystals of a kind in great numbers, which scatter light and make for instance a candle appear white.
- stearine has a clearly defined melting point (about 58°C) , above which it becomes transparent.
- melting point about 58°C
- stearines with different melting points so that appropriate alarm threshold temperatures are easy enough to find.
- paraffins, waxes, certain fats and oils There are several other similar materials, such as paraffins, waxes, certain fats and oils. Seme of the plastics also turn clear from milky condition when they melt (for instance, polyethylene). All told there exists a quite ample selection of suitable materials and suitable melting or phase transformation teirperatures.
- fibre optics are employed to observe the change in light scattering and the change of light transmission at the melting point or other phase transformation point of the respective material.
- thermometer or heat alarm device of the invention making use of fibre optics is characterized in that the measuring instrument consists of a fibre-optic light transmitter, which sends cut light along an cptic fibre tc a measuring head provided on the end of the transmitting fibre, and of a fibre-optic receiver, which is connected by an optic fibre to the same measuring head, and that the measuring head consists of a chamber or hollow enclosure which has been filled with a light-scattering substance of the kind which below a given threshold temperature scatters the light earning through the transmitting fibre back into the receiving fibre but above the threshold temperature diaracteristic of the material loses its light scattering capacity, or becomes transparent, so that the light arriving through the transmitting fibre is no longer scattered to the receiving fibre, whereby transgression of the threshold teirperature characteristic of said substance is observable in the fibre-optic receiver as a diminishing of the back-scattered light and of the signal which it produces.
- Fig.1 presents an advantageous embodiment of the thermometer, or teirperature alarm device, of the invention in which two separate cptic fibres are used, in the form of a schematical diagram.
- Fig.2 presents a second advantageous embodiment of the thermometer, or temperature alarm device, of the invention in which one single optic fibre is used, in the form of a schematical diagram.
- Fig.3 presents a third advantageous embodiment of the thermometer, or temperature alarm device, of the invention in which the light transmission is directly utilized with the aid of optic fibres, in the form of a schematical diagram.
- a fibre-optic light transmitter transmits light at a suitable wavelength; in many cases the visible light from a so-called LED lamp is sufficient, tut for instance near infra-red li ⁇ t may also be used.
- the light from the fibre-optic light transmitter 1 proceeds along the fibre 2 to the measuring head 5, which is for instance a measuring cell 6, which has been closely filled with a suitable substance 7, for instance stearine.
- the light arriving in the transmitter fibre 2 is scattered back from the stearine in such manner that part of it enters the second optic fibre 4 carried to the measuring cell 6 and along which fibre the scattered light reaches the fibre-optic receiver 3, the light arriving there being converted to an electronic signal by means kncwn in themselves in electro-optics.
- Fig. 2 is presented a design which contains only one fibre and which may therefore be better usable in some situations.
- the fibre-optic light transmitter 8 as well as the fibres cptic receiver 9 has been connected to one and the same fibre. using a so-called semitranspare ⁇ t mirror 10.
- the light proceeding along the fibre 11 arrives at a similar measuring cell 12 as in the precedine embodiment, and if conditions are below the threshold temperature, the stearine or equivalent light-scattering substance in the measuring cell 12 scatters light back along the fibre 11 to the receiver 9, where the light signal, or its absence, can be electronically detected in ways known in the art.
- the semitransparent mirror 10 used in this embodiment constitutes a design known in itself in electro-optics and therefore needs no special description.
- Fig. 3 is presented a third embodiment, wherein a fibre-optic transmitter 13 has been connected to a fibre-optic receiver 14 with the aid of a measuring cell 16 and an optic fibre 15 in such manner that when the material in the measuring cell 16 melts or otherwise becomes transparent the light from the transmitter 13 can proceed through the measuring cell 16 all the way to the receiver 14, whereby the threshold temperature causing melting can be electronically recorded in the receiver 14.
- waxes like paraffin and stearine, have melting temperatures which occur in rather in-teresting ranges.
- Very common melting points of stearine are the temperatures 58, 68 and 78°C, which are located in highly useful ranges in view of practical monitoring operations, for instance.
- So-called micrccrystalline stearine waxes are also available which have melting points in even higher ranges.
- paraffins for instance, have a number of useful melting points. These melting points are usually quite stable, and changes of barometric pressure, for instance, have little if any effect on them.
- Stearines and other waxes are also in themselves very durable and stable substances, with minimal chemical changes in the course of time even if they should remain in molten state for prolonged periods.
- the measuring cell may be sealed so tightly that other solvent chemicals cannot destroy the specimens or cause them to change. It is understood that submersion of the pick-up in any oil naturally calls for extra protection, but this circumstance is no essential part of the invention in itself. Stearines and waxes are also insensitive to electric and magnetic fields. It may also be noted that the melting and solidifying process e.g. of waxes incorporates a certain hysteresis phenomenon, which is nothing but an advantage in alarm actuating applications.
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Temperature Or Quantity Of Heat (AREA)
- Radiation Pyrometers (AREA)
Abstract
A thermometer or temperature alarm device making use of fibre optics. The measuring instrument consists of a fibre-optic light transmitter (1), which sends out light along an optic fibre (2) to a measuring head (5) on the end of the transmitting fibre (2), and a fibre-optic receiver (3), which is connected with an optic fibre (4) to the same measuring head (5). The measuring head (5) consists of a cell or hollow enclosure (6) which has been filled with a light-scattering substance (7) of the kind which below a certain threshold temperature scatters the incident light from the transmitting fibre (2) back to the receiving fibre (4) but above the threshold temperature characteristic for the substance (7) loses its light scattering capacity or changes to be transparant so that the light coming from the transmitting fibre (2) is no longer scattered to the receiving fibre (4). Transgression of the threshold temperature characteristic for the substance (7) is observable in the fibre-optic receiver (3) as a diminishing of the back-scattered light and of the signal thereby caused.
Description
Fibre-optic thermomater or temperature alarm device
The present invention concerns a therrroneter or temperature alarm device making use of fibre optics.
It is necessary in numerous supervision tasks within industry and technology to measure temperature in such a way that an alarm is actuated when the temperature has transgressed a given threshold value. Of course such threshold alarm can be obtained from a conventional electronic thermometer by providing electronic circuits for threshold detection so that an alarm is actuated if the preset temperature is surpassed.
There are however various situations in which one would prefer to forgo the use of a so-called electronic thermometer because such instruments as a rule contain an electrically conductive measuring pick-up, or sensor, to which a voltage has been applied. Typical objects of measurement where this consideration is relevant are, for instance, warehouses containing readily inflammable chemicals, e.g. oil tanks and cisterns, powder stores, etc. In such conditions the electrically conductive pick-up leads may give rise to sparking, and they may for instance carry lightning into the storage space, with disastrous results.
It is possible, of course, in such situations to use so-called temperature pick-ups utilizing fibre optics, which continuously follow the development of temperature and which can be programmed to actuate an alarm if a given critical temperature is surpassed. As is commonly known, measuring instruments, such as thermometers, using fibre optics have the inherent advantage that the optic fibre itself is an insulator and thus cannot cause any harmful electrical phenomena, such as short circuits or sparking, which might cause dangerous situations in an environment susceptible to explosion.
However, fibre-optic thermometers of present art have turned out to be rather complicated and expensive, and this has limited their use. On the other hand, thermometers employing conventional galvanic technology, such as thermocouples, thermistors or NTC and PIC resistance elements, offer a rather inexpensive and reliable solution to surveillance problems as long as there is no apprehension rega-rding risk of fire or explosion. It is possible especially with PIC and NTC resistors to implement a temperature detection which is specifically of the alarm type because the resistance of these resistors changes most powerfully as a function of temperature in various temperature ranges.
Ihe fibre-optic thermometers known at present are based on the principle that light is carried with an optic fibre to a measuring cell and the material in this cell reacts in one way or another to the temperature so that the change of temperature can be observed by optical means.
One way known in the art is to make use of the temperature dependence of the fluorescence phenomenon caused by light. It is a well-known fact that the intensity becomes less with increasing temperature. Some of the commercially available measuring instruments are based on this phenomenon.
It is also known that the properties of so-called liquid crystals are dependent on temperature in such a way that it is possible to construct thermometers using liquid crystals. Liquid crystals cause a kind of interference phencmena in thin films so that the colour of the liquid crystal film appears to change as a function of temperature in desired manner. A type of paint ccarposed of liquid crystals is known which can be used to coat those objects which are of interest, and one may then observe the changing colour by those means which fibre optics afford. It has to be noted, hcwever, that liquid crystal materials have no particularly long life span: in a way, they are decomposed as they age.
In the present invention is disclosed a fibre-optic thermometer differing frcm that which has been described above and which can be used to observe the temperature in a given space and to obtain alarm if the temperature rises over a given critical value. These critical values depend on the material that has been placed in the sensor itself and they are therefore highly reliable and reproducible because in their case no thought need be given to the potential creep of electronically set threshold values. In other words, the threshold values can be derived from the material parameters of the sensor material itself. The pick-ups to be presented here are furthermore highly reliable, simple and inexpensive, as will become apparent later on.
For better understanding the way in which the pick-up operates, the following situation shall be considered in which e.g. in a test tube of glass has been placed snow. When for instance a narrow laser light beam is directed on this test tube, it will be found that no light can pass through the test tube: the light is all scattered frcm the sncw surface. Snew is white, a well-known fact, because it scatters nearly all of the incident light. But if the contents of the test tube are warmed so that the sncw therein melts, all light can pass through and hardly anything is scattered back frcm the surface of the test tube. One knows in that case that the temperature has definitely increased to be higher than the melting point of sncw, i.e., 0°C. It follows that in this instance light transmission can be taken as threshold indication of 0°C temperature. It is obvious, of course, that if the light is introduced with the aid of an optic fibre and its transmission is observed with.another cptic fibre, it becomes possible to construct a fibre-optic threshold detector.
In the prespent invention a separate sensor housing is used, which is filled with a material of the above-described kind and the optical properties of which are monitored with optic fibres. Optic fibre transmitters and receivers are known in the art in themselves, but all the same they constitute an important component part in
the present invention. Said sensor housing may be filled with a material which melts and turns transparent above a certain temperature which is characteristic for the material in question but is solid and scatters back a great part of the light incident on it, at temperatures below said melting point. Stearine may be mentioned as an example. Below its melting point stearine is white and kind of milky, and it scatters back all light. When it melts, stearine turns transparent and clear like water and transmits all light. Stearine in solid state contains microcrystals of a kind in great numbers, which scatter light and make for instance a candle appear white. On the other hand, stearine has a clearly defined melting point (about 58°C) , above which it becomes transparent. There is available a rather great number of stearines with different melting points so that appropriate alarm threshold temperatures are easy enough to find. There are several other similar materials, such as paraffins, waxes, certain fats and oils. Seme of the plastics also turn clear from milky condition when they melt (for instance, polyethylene). All told there exists a quite ample selection of suitable materials and suitable melting or phase transformation teirperatures. It is also possible to admix light-scattering crystals to certain oils, which crystals as they melt either let the light pass through or cease to scatter light. In the present invention fibre optics are employed to observe the change in light scattering and the change of light transmission at the melting point or other phase transformation point of the respective material.
It should be clear from the preceding description that a pick-up of this type would be rather simple, inexpensive and reliable in operation owing to its being based on a simple natural phenomenon.
The thermometer or heat alarm device of the invention making use of fibre optics is characterized in that the measuring instrument consists of a fibre-optic light transmitter, which sends cut light along an cptic fibre tc a measuring head provided on the end of the transmitting fibre, and of a fibre-optic receiver, which is connected by an optic fibre to the same measuring head, and that
the measuring head consists of a chamber or hollow enclosure which has been filled with a light-scattering substance of the kind which below a given threshold temperature scatters the light earning through the transmitting fibre back into the receiving fibre but above the threshold temperature diaracteristic of the material loses its light scattering capacity, or becomes transparent, so that the light arriving through the transmitting fibre is no longer scattered to the receiving fibre, whereby transgression of the threshold teirperature characteristic of said substance is observable in the fibre-optic receiver as a diminishing of the back-scattered light and of the signal which it produces.
For better understanding of the invention, the design solutions therewith associated shall be gone through in greater detail in the following. An initial observation: the fibre-optic transmitters and receivers are in themselves known in the art and are commercially obtainable as completed units; therefore they are not more closely described here althouφ they constitute part of the invention.
The invention is described in detail with reference to certain advantageous embodiments of the invention, presented in the figures of the appended drawing, to which however the invention is not meant to be exclusively confined.
Fig.1 presents an advantageous embodiment of the thermometer, or teirperature alarm device, of the invention in which two separate cptic fibres are used, in the form of a schematical diagram.
Fig.2 presents a second advantageous embodiment of the thermometer, or temperature alarm device, of the invention in which one single optic fibre is used, in the form of a schematical diagram.
Fig.3 presents a third advantageous embodiment of the thermometer, or temperature alarm device, of the invention in which the light transmission is directly utilized with the aid of optic fibres, in
the form of a schematical diagram.
In Fig. 1, a fibre-optic light transmitter transmits light at a suitable wavelength; in many cases the visible light from a so-called LED lamp is sufficient, tut for instance near infra-red liφt may also be used. The light from the fibre-optic light transmitter 1 proceeds along the fibre 2 to the measuring head 5, which is for instance a measuring cell 6, which has been closely filled with a suitable substance 7, for instance stearine. The light arriving in the transmitter fibre 2 is scattered back from the stearine in such manner that part of it enters the second optic fibre 4 carried to the measuring cell 6 and along which fibre the scattered light reaches the fibre-optic receiver 3, the light arriving there being converted to an electronic signal by means kncwn in themselves in electro-optics. When new the melting point of stearine is reached, the crystallinity of the substance disappears, and this is indicated by the electronic circuit of the fibre-optic receiver 3 as an alarm signal. It should be noted that in an alarm device of this type a signal is received in the receiver 3 all the time while the teirperature is below the alarm threshold. This can ce characterized as a so-called closed-circuit (continuous current) principle: everything is OK if a return light signal is received; if the light signal has vanished, then either the threshold teirperature has been surpassed or the optic fibre has been broken and the condition requires attention in every case.
In Fig. 2 is presented a design which contains only one fibre and which may therefore be better usable in some situations. In this design the fibre-optic light transmitter 8 as well as the fibres cptic receiver 9 has been connected to one and the same fibre. using a so-called semitranspareπt mirror 10. The light proceeding along the fibre 11 arrives at a similar measuring cell 12 as in the precedine embodiment, and if conditions are below the threshold temperature, the stearine or equivalent light-scattering substance in the measuring cell 12 scatters light back along the fibre 11 to the receiver 9, where the light signal, or its absence, can be
electronically detected in ways known in the art. It should be noted that the semitransparent mirror 10 used in this embodiment constitutes a design known in itself in electro-optics and therefore needs no special description.
In Fig. 3 is presented a third embodiment, wherein a fibre-optic transmitter 13 has been connected to a fibre-optic receiver 14 with the aid of a measuring cell 16 and an optic fibre 15 in such manner that when the material in the measuring cell 16 melts or otherwise becomes transparent the light from the transmitter 13 can proceed through the measuring cell 16 all the way to the receiver 14, whereby the threshold temperature causing melting can be electronically recorded in the receiver 14.
it may furthermore be noted that many waxes, like paraffin and stearine, have melting temperatures which occur in rather in-teresting ranges. Very common melting points of stearine are the temperatures 58, 68 and 78°C, which are located in highly useful ranges in view of practical monitoring operations, for instance. So-called micrccrystalline stearine waxes are also available which have melting points in even higher ranges. Also paraffins, for instance, have a number of useful melting points. These melting points are usually quite stable, and changes of barometric pressure, for instance, have little if any effect on them. Stearines and other waxes are also in themselves very durable and stable substances, with minimal chemical changes in the course of time even if they should remain in molten state for prolonged periods. Moreover, the measuring cell may be sealed so tightly that other solvent chemicals cannot destroy the specimens or cause them to change. It is understood that submersion of the pick-up in any oil naturally calls for extra protection, but this circumstance is no essential part of the invention in itself. Stearines and waxes are also insensitive to electric and magnetic fields. It may also be noted that the melting and solidifying process e.g. of waxes incorporates a certain hysteresis phenomenon, which is nothing but an advantage in alarm actuating applications.
Claims
1. A thermometer or temperature alarm device making use of fibre optics, characterized in that the measuring instrument consists of a fibre-optic light transmitter (1), which sends cut light along an cptic fibre (2) to a measuring head (5) on the end of the transmitting fibre (2) , and of a fibre-optic receiver (3) , which is connected with an optic fibre (4) to the same measuring head (5), and that the measuring head (15) consists of a cell or hollow enclosure (6) which has been filled with a light-scattering substance (7) of the kind which below a certain threshold temperature scatters the incident light from the transmitting fibre (2) back, to the receiving fibre (4) but above the threshold temperature characteristic for the substance (7) loses its light scattering capacity or changes to be transparent so that the light coming from the transmitting fibre (2). is no longer scattered to the receiving fibre (4) , whereby transgression of the threshold temperature characteristic for the substance (7) is observable in the fibre-optic receiver (3) asia diminishing of the back-scattered light and of the signal thereby caused.
2. Thermometer or temperature alarm device making use of fibre optics, characterized in that the measuring instrument consists of a fibre-optic transmitter (8) and a fibre-optic receiver (9) which are with the aid of a semitransparent mirror (10) combined on one fibre (11) which has been connected to a measuring cell or hollow enclosure (12) which is filled with a substance of which the optical light scattering capacity below a certain threshold temperature causes scattering of the light arriving through the fibre (11) back into the fibre (11) and by that route to the optical receiver (9) but above a certain threshold temperature characteristic for the substance in question loses its light scattering capacity or turns transparent so that transgression of said threshold temperature is observable in the optical receiver (9) as a diminishing of the back-scattered light.
3. Thermometer or temperature alarm device making use of fibre optics, characterized in that a separate fibre-optic transmitter (13) and receiver (14) are over a measuring cell or hollow enclosure (16) interconnected with an cptic fibre (15) so that above a threshold temperature characteristic for the substance in the measuring cell (16) the substance in the measuring cell (16) turns transparent to light so that transgression of the threshold temperature is observable in the receiver (14) as an increase of the electronic signal caused by the light signal.
4. Thermometer or temperature alarm device making use of fibre optics according to any one of claims 1-3, characterized in that the substance in the measuring cell or hollow enclosure is paraffin, stearine, plastic or another equivalent substance of which the light scattering capacity is high below a certain threshold temperature characteristic for the substance but above, a certain threshold temperature characteristic for the substance the substance loses its light scattering capacity or turns transparent.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE8787901491T DE3766781D1 (en) | 1986-02-12 | 1987-02-11 | Faseroptisches thermometer oder temperaturwarnanordnung. |
| NO874189A NO874189L (en) | 1986-02-12 | 1987-10-06 | FIBER OPTICS THERMOMETER OR TEMPERATURAL ALARM DEVICE. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI860632 | 1986-02-12 | ||
| FI860632A FI860632A7 (en) | 1986-02-12 | 1986-02-12 | Fiber optic temperature alarm. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO1987005103A1 true WO1987005103A1 (en) | 1987-08-27 |
Family
ID=8522138
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/FI1987/000024 Ceased WO1987005103A1 (en) | 1986-02-12 | 1987-02-11 | Fibre-optic thermometer or temperature alarm device |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4906107A (en) |
| EP (1) | EP0259412B1 (en) |
| JP (1) | JPS63502531A (en) |
| FI (1) | FI860632A7 (en) |
| WO (1) | WO1987005103A1 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH677971A5 (en) * | 1988-08-26 | 1991-07-15 | Asea Brown Boveri | |
| US5779365A (en) * | 1992-11-25 | 1998-07-14 | Minnesota Mining And Manufacturing Company | Temperature sensor for medical application |
| US6019507A (en) * | 1992-11-25 | 2000-02-01 | Terumo Cardiovascular Systems Corporation | Method of making temperature sensor for medical application |
| WO2003081193A1 (en) * | 2002-03-27 | 2003-10-02 | Council Of Scientific And Industrial Research | Intensity modulated fiber optic temperature switching immersion probe |
| KR100885756B1 (en) * | 2002-03-27 | 2009-02-26 | 카운슬 오브 사이언티픽 앤드 인더스트리얼 리서치 | Intensity Modulated Fiber Optic Temperature Switching Immersion Probe |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US6527440B1 (en) * | 2000-08-31 | 2003-03-04 | Siemens Westinghouse Power Corporation | Optical power generator system condition status indicator and methods of indicating same |
| US6827842B2 (en) * | 2001-10-19 | 2004-12-07 | Exxonmobil Research & Engrg. Co. | On-line determination of wax crystallization temperature of waxy solvent stream |
| US20040252748A1 (en) * | 2003-06-13 | 2004-12-16 | Gleitman Daniel D. | Fiber optic sensing systems and methods |
| US20060291532A1 (en) * | 2005-06-27 | 2006-12-28 | Intel Corporation | Method and apparatus for measurement of skin temperature |
| US8277119B2 (en) | 2006-12-19 | 2012-10-02 | Vibrosystm, Inc. | Fiber optic temperature sensor |
| JP5288884B2 (en) * | 2008-05-27 | 2013-09-11 | アズビル株式会社 | Fluorescent temperature sensor |
| JP5786191B2 (en) * | 2009-09-30 | 2015-09-30 | イマジニアリング株式会社 | Temperature sensitive body, optical temperature sensor, temperature measuring device and heat flux measuring device |
| CN106707404A (en) * | 2017-01-16 | 2017-05-24 | 北京交通大学 | Novel optical fiber used for temperature monitoring and early warning |
| CN117168646A (en) * | 2023-07-18 | 2023-12-05 | 华能北京热电有限责任公司 | A high temperature alarm device for plum blossom contacts |
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- 1987-02-11 WO PCT/FI1987/000024 patent/WO1987005103A1/en not_active Ceased
- 1987-02-11 US US03/271,088 patent/US4906107A/en not_active Expired - Fee Related
- 1987-02-11 EP EP87901491A patent/EP0259412B1/en not_active Expired - Lifetime
- 1987-02-11 JP JP62501274A patent/JPS63502531A/en active Pending
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| US4307607A (en) * | 1979-07-16 | 1981-12-29 | Electric Power Research Institute, Inc. | Temperature sensing arrangement and method |
| EP0146522A2 (en) * | 1983-12-07 | 1985-06-26 | Monsanto Company | Polymeric/optical sensing apparatus and method |
| WO1985005447A1 (en) * | 1984-05-24 | 1985-12-05 | Thalmond Anstalt | Device for measuring a physical magnitude |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH677971A5 (en) * | 1988-08-26 | 1991-07-15 | Asea Brown Boveri | |
| US5779365A (en) * | 1992-11-25 | 1998-07-14 | Minnesota Mining And Manufacturing Company | Temperature sensor for medical application |
| US6019507A (en) * | 1992-11-25 | 2000-02-01 | Terumo Cardiovascular Systems Corporation | Method of making temperature sensor for medical application |
| US6283632B1 (en) | 1992-11-25 | 2001-09-04 | Terumo Cardiovascular Systems Corporation | Method of measuring temperature |
| WO2003081193A1 (en) * | 2002-03-27 | 2003-10-02 | Council Of Scientific And Industrial Research | Intensity modulated fiber optic temperature switching immersion probe |
| KR100885756B1 (en) * | 2002-03-27 | 2009-02-26 | 카운슬 오브 사이언티픽 앤드 인더스트리얼 리서치 | Intensity Modulated Fiber Optic Temperature Switching Immersion Probe |
Also Published As
| Publication number | Publication date |
|---|---|
| FI860632A0 (en) | 1986-02-12 |
| FI860632L (en) | 1987-11-18 |
| JPS63502531A (en) | 1988-09-22 |
| US4906107A (en) | 1990-03-06 |
| EP0259412B1 (en) | 1990-12-19 |
| EP0259412A1 (en) | 1988-03-16 |
| FI860632A7 (en) | 1987-11-18 |
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