JP2010210246A - Fluorescent temperature sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorescent temperature sensor capable of preventing deficiency of an optical fiber by preventing application of an excessive load on the optical fiber caused by expansion/contraction of a protection tube by an ambient temperature, concerning the fluorescent temperature sensor wherein the optical fiber is held in the protection tube. <P>SOLUTION: This fluorescent temperature sensor 1 includes a phosphor 4 emitting fluorescence by receiving irradiation of excitation light, a light projection part 9 for projecting excitation light to the phosphor 4, a light receiving part 10 for receiving fluorescence emitted from the phosphor 4, the optical fiber 5 for guiding light between the light projection part 9 and the light receiving part 10 and the phosphor 4, the protection tube 7 for protecting the optical fiber 5, and a processing part 11 for calculating a temperature based on a received light amount by the light receiving part 10. The optical fiber 5 is stored in the protection tube 7, and formed longer than the protection tube 7. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fluorescence temperature sensor that measures temperature using a phosphor whose fluorescence characteristics change with temperature.

  As a temperature sensor, a fluorescent temperature sensor using a phosphor is widely used. This fluorescence temperature sensor measures temperature by using a phosphor whose fluorescence characteristics change with temperature. Specifically, the fluorescent light generated by the phosphor is detected by irradiating the phosphor with excitation light from a light source. And temperature is measured by the change of fluorescence characteristics, such as fluorescence lifetime.

  In the fluorescence temperature sensor as described above, in order to perform mechanically stable temperature measurement, as shown in FIG. 4, a powdery phosphor 101 is packed at the tip of the protective tube 102 and the phosphor 101 is stored. There is a fluorescent temperature sensor configured such that an optical fiber 103 is inserted into a protective tube 102, the protective tube 102 and the optical fiber 103 are fixed with an adhesive, and the optical fiber 103 is held by a buffer material 104 (for example, Patent Document 1). reference).

US Pat. No. 5,355,423

  However, in the fluorescent temperature sensor disclosed in Patent Document 1, the protective tube 102 expands and contracts due to the ambient temperature, and the optical fiber 103 and the buffer material 104 expand and contract accordingly. At this time, since the thermal expansion coefficients of the protective tube 102, the optical fiber 103, and the buffer material 104 are different, there is a problem that an excessive load is applied to the optical fiber 103. In addition, there is a problem that the optical fiber 103 and the buffer material 104 are rubbed due to expansion and contraction of the optical fiber 103 and the buffer material 104 having different thermal expansion coefficients, and the optical fiber 103 is broken.

  The present invention has been made to solve the above-described problems. In a fluorescent temperature sensor in which an optical fiber is held in a protective tube, the light held in the protective tube as the protective tube expands and contracts due to the ambient temperature. An object of the present invention is to provide a fluorescence temperature sensor that can prevent the optical fiber from being damaged without excessive load being applied to the optical fiber when the fiber expands and contracts.

  A fluorescence temperature sensor according to the present invention includes a phosphor that emits fluorescence upon receiving irradiation of excitation light, a light projecting unit that projects excitation light onto the phosphor, a light receiving unit that receives fluorescence emitted from the phosphor, and a projector. In a fluorescence temperature sensor comprising an optical fiber for guiding light between a light part and a light receiving part and a phosphor, a protective tube for protecting the optical fiber, and a processing part for calculating a temperature based on the amount of light received by the light receiving part The optical fiber is housed in a protective tube and formed longer than the length of the protective tube.

  According to this invention, since it is configured as described above, in the fluorescence temperature sensor in which the optical fiber is held in the protective tube, when the optical fiber held in the protective tube expands and contracts with the expansion and contraction of the protective tube due to the ambient temperature In addition, an excessive load is not applied to the optical fiber, and the optical fiber can be prevented from being damaged.

It is a figure which shows the structure of the fluorescence temperature sensor which concerns on Embodiment 1 of this invention. It is a figure which shows the structure of the protective tube of the fluorescence temperature sensor which concerns on Embodiment 1 of this invention. It is a figure which shows the structure of the protective tube of the fluorescence temperature sensor which concerns on Embodiment 2 of this invention. It is a figure which shows the structure of the conventional fluorescence temperature sensor.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a diagram showing the structure of a fluorescent temperature sensor 1 according to Embodiment 1 of the present invention.
As shown in FIG. 1, a fluorescence temperature sensor 1 is brought into contact with a surface to be measured, a sensor probe 2 for emitting fluorescence according to temperature, and excitation light is projected onto the sensor probe 2. And a sensor module 3 for measuring the temperature of the surface to be measured from the amount of the received light.

  As shown in FIG. 1, the sensor probe 2 guides the phosphor 4 that emits fluorescence by the excitation light projected from the sensor module 3 and the excitation light projected by the sensor module 3 to the phosphor 4. In order to guide the fluorescence emitted from the phosphor 4 to the sensor module 3, an optical fiber 5 connected between the sensor module 3 and the phosphor 4 and a cover 6 provided at the tip of the sensor probe 2 and covering the phosphor 4. And a protective tube 7 that protects the optical fiber 5 from damage. The phosphor 4 can take various forms such as a powder, a pellet, or a molded and sintered one.

  As shown in FIG. 1, the sensor module 3 includes a light projecting unit 9 for projecting excitation light onto the phosphor 4 provided on the sensor probe 2 by the driving unit 8, and a phosphor 4 provided on the sensor probe 2. The light receiving unit 10 for receiving the fluorescence emitted by the light receiving unit 10 and the processing unit 11 for calculating the temperature of the surface to be measured based on the amount of light received by the light receiving unit 10.

Next, the operation of the fluorescence temperature sensor 1 configured as described above will be described.
First, the surface of the cover 6 in which the phosphor 4 provided at the tip of the sensor probe 2 of the fluorescence temperature sensor 1 is housed is brought into contact with the surface to be measured. Next, excitation light is projected from the light projecting unit 9 onto the phosphor 4. The phosphor 4 emits fluorescence by the excitation light projected from the light projecting unit 9. The light receiving unit 10 receives the fluorescence emitted by the phosphor 4. The amount of light received by the light receiving unit 10 at this time is measured by the processing unit 11 one by one. Next, the light projecting unit 9 stops projecting the excitation light to the phosphor 4. Thereby, the phosphor 4 is quenched. The extinction speed of the phosphor 4 increases as the temperature increases. The processing unit 11 measures the extinction speed of the phosphor 4 to measure the temperature of the surface to be measured.

Next, the structure of the protective tube 7 of the fluorescence temperature sensor 1 configured as described above will be described in detail.
FIG. 2 is a diagram showing the structure of the protective tube 7 of the fluorescence temperature sensor 1 according to Embodiment 1 of the present invention.
As shown in FIG. 2, an optical fiber 5 is accommodated in a protective tube 7 provided in the sensor probe 2.

The optical fiber 5 is for guiding the excitation light projected by the light projecting unit 9 or the fluorescence emitted by the phosphor 4, and between the phosphor 4 and the light projecting unit 9 and between the phosphor 4 and the light receiving unit 10. Connected to. The optical fiber 5 is composed of, for example, a single-core plastic optical fiber. Further, the optical fiber 5 is configured by using an optical fiber having a diameter of about 100 μm in order to bend easily in the protective tube 7 provided in the sensor probe 2.
The optical fiber 5 configured as described above is accommodated in the protective tube 7 such that the length of the optical fiber 5 in the portion accommodated in the protective tube 7 is longer than the length of the protective tube 7. .

The protective tube 7 is for protecting the optical fiber 5 from being damaged, and is made of, for example, stainless steel. The protective tube 7 holds the optical fiber 5 accommodated therein by fixing the optical fiber 5 at both ends of the protective tube 7 with an adhesive or welding. At this time, when the protective tube 7 is made of metal, it can be fixed by welding and brazing. Here, the optical fiber 5 is held in the protective tube 7 so as not to contact the protective tube 7.
In addition, an air layer 12 is formed between the optical fiber 5 and the protective tube 7, and the air layer 12 serves as a heat insulating material for preventing heat transfer from the outside to the optical fiber 5. .

  In this way, the length of the optical fiber 5 in the portion accommodated in the protective tube 7 and held at both ends of the protective tube 7 is set longer than the length of the protective tube 7, and the optical fiber 5 Since the optical fiber 5 is bent in the protective tube 7 by providing the air layer 12 between the protective tube 7 and the protective tube 7, the protective tube 7 expands and contracts due to the ambient temperature. When the optical fiber 5 expands and contracts, an excessive load is not applied to the optical fiber 5 due to the bending of the optical fiber 5 in the protective tube 7.

  As described above, according to the first embodiment, in the optical fiber 5 that is held by fixing both ends of the protective tube 7 with an adhesive or the like, the protective tube 7 is longer than the length of the protective tube 7. The length of the optical fiber 5 in the portion accommodated therein is set long, and the air layer 12 is provided between the optical fiber 5 and the protective tube 7 so that the optical fiber 5 is bent in the protective tube 7. Since it comprised, when the protective tube 7 expand | swells and shrink | contracts by ambient temperature, an excessive load is not added to the optical fiber 5, and the defect | deletion of the optical fiber 5 can be prevented.

  Moreover, by forming the air layer 12 between the optical fiber 5 and the protective tube 7, the optical fiber 5 can be insulated and the influence of external heat transmitted to the phosphor 4 connected to the optical fiber 5 is suppressed. Accurate temperature measurement.

Embodiment 2. FIG.
FIG. 3 is a diagram showing the structure of the protective tube 7 of the fluorescence temperature sensor 1 according to Embodiment 2 of the present invention.
In the fluorescence temperature sensor 1 according to the first embodiment described above, the optical fiber 5 is held and fixed by fixing with adhesive or welding at both ends of the protective tube 7, but as shown in FIG. A heat-shrinkable tube or a metal pipe may be used for the protective tube 7 so that both ends of the protective tube 7 are contracted to hold the optical fiber 5, and the same effect as in the first embodiment can be obtained. It is done.

  In the fluorescent temperature sensor 1 according to Embodiments 1 and 2 of the present invention, the optical fiber 5 has been described using a single-core optical fiber. However, the present invention is not limited to this, and a multi-core optical fiber or bundle is used. You may comprise with an optical fiber.

DESCRIPTION OF SYMBOLS 1 Fluorescence temperature sensor 2 Sensor probe 3 Sensor module 4 Phosphor 5 Optical fiber 6 Cover 7 Protection tube 8 Drive part 9 Light projection part 10 Light reception part 11 Processing part 12 Air layer

Claims (3)

A phosphor that emits fluorescence when irradiated with excitation light; and
A light projecting unit that projects excitation light onto the phosphor;
A light receiving portion for receiving fluorescence emitted by the phosphor;
An optical fiber for guiding light between the light projecting unit and the light receiving unit and the phosphor;
A protective tube for protecting the optical fiber;
In a fluorescence temperature sensor comprising a processing unit that calculates a temperature based on the amount of light received by the light receiving unit,
The fluorescent temperature sensor according to claim 1, wherein the optical fiber is housed in the protective tube and is formed longer than a length of the protective tube.   The fluorescent temperature sensor according to claim 1, wherein an air layer is provided at least at a part between the optical fiber and the protective tube.   The fluorescence temperature sensor according to claim 1 or 2, wherein the protective tube is constituted by a heat shrinkable tube, and both ends of the optical fiber are fixed by contracting both ends of the protective tube.

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