JP2012163459A - Optical fiber temperature sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber temperature sensor capable of constantly monitoring temperature at a desired position inside an induction heating device utilized in a steel hot rolling line.SOLUTION: An optical temperature sensor is formed by installing an optical fiber cable 13 inside a housing 8 and 9 made of an ultrathin type sheet which is an equivalent material to an insulation material used for an induction heating device. A plurality of ultrathin cylindrical materials 14, made of the same material as the housing, are installed at a plurality of locations inside the housing. A plurality of sensing rings 15 are formed by winding the optical fiber cable 13 around respective ultrathin cylindrical materials 14, without being fixed thereto, at a length longer than the length corresponding to a distance resolution. Temperatures at a plurality of locations are measured by the plurality of the sensing rings 15.

Description

  The present invention relates to an optical fiber temperature sensor that constantly monitors the temperature inside an induction heating apparatus that is operated in a hot rolling line for steel.

 In a hot rolling line for steel, a heating furnace heats a material to be heated (rolled material) to a temperature at which rolling is possible in advance, and a roughing mill forms the material to be heated into a state called a coarse bar. Further, the finish rolling mill forms the coarse bar into a thin plate having a desired plate thickness and plate width. In such a hot rolling line for steel, an induction heating device is used for the purpose of reducing the load on the rolling mill and raising the temperature and soaking the coarse bar against the decrease in the coarse bar temperature during line conveyance. .

  As this induction heating apparatus, an edge heater for increasing the temperature of both edge portions of the coarse bar and a bar heater for increasing the temperature of the entire coarse bar are generally known. This bar heater is mainly formed of an iron core, a heating coil, and a heat-resistant plate, and the iron core, the heating coil, and the heat-resistant plate are covered with a shield cover.

 Radiant heat, scale and deske water from the rough bar conveyed in this hot rolling line enter the induction heating device, causing overheating / burning of the heating coil and iron core, dielectric breakdown, and reduced life. .

  In particular, the method of confirming the state in which the scale, deske water, etc. permeate the heating coil portion that is most susceptible to the influence inside the induction heating apparatus relies on the open inspection of the shield cover during the line downtime.

 Furthermore, even if the induction heating device is quickly restored after a trouble occurs, the induction heating device cannot be restored in a limited line downtime, and the operation may be stopped for a long time.

 For this reason, in the hot rolling line for steel, the monitoring method for preventing the sudden trouble of the induction heating apparatus operated by a bad environmental condition is required. As this monitoring method, there is a temperature monitoring device using an optical fiber. This temperature monitoring device is described in Patent Document 1, for example, and is used in various fields such as tunnel disaster prevention facilities.

  The tunnel disaster prevention facility described in Patent Document 1 causes the entire length of one optical fiber cable installed in the length direction of the tunnel to function as a temperature sensor, and the temperature over the entire length from one end to the other end of the optical fiber cable. The fire is detected by measuring the distribution at once.

  However, although the tunnel disaster prevention facility described in Patent Document 1 can measure the temperature distribution along the longitudinal direction of the optical fiber cable, the temperature measurement point is determined by the distance resolution. For this reason, tunnel disaster prevention facilities are used for large-scale components or large-scale linear structures represented by tunnels. Optical fiber temperature monitoring devices are installed in extremely narrow spaces inside equipment. It was not possible to use it as it was.

  Patent Document 2 is known as an optical fiber temperature monitoring device applied to this narrow space. The optical fiber temperature sensor described in Patent Document 2 measures the local temperature by winding an optical fiber cable over a length corresponding to the distance resolution. In this patent document 2, the sensor part is fixed with an adhesive together with a filler having good thermal conductivity, and is arranged in contact with the object to be measured.

JP-A-8-4499 Japanese Patent Laid-Open No. 7-181086

  However, the temperature measurement accuracy is lowered by fixing the optical fiber cable itself together with a filler having good thermal conductivity with an adhesive. In addition, by fixing the optical fiber cable itself, for example, when the optical fiber cable itself is subjected to excessive expansion or contraction, or when the optical fiber cable itself receives an excessive force, the optical fiber cable itself may be disconnected and temperature measurement may not be possible. .

  An object of the present invention is to provide an optical fiber temperature sensor that can always measure the temperature at a desired position of a heating coil of an induction heating device even in a poor environment, even when subjected to repeated thermal expansion and contraction or excessive force.

  In order to solve the above problems, the optical fiber temperature sensor of the present invention has the following means. Invention of Claim 1 is an optical fiber temperature sensor installed in the induction heating apparatus installed in the hot rolling line for steel, The pole using the material equivalent to the insulating material used for the said induction heating apparatus An optical fiber cable is housed in a casing made of a thin sheet.

  According to a second aspect of the present invention, in the optical fiber temperature sensor according to the first aspect, a plurality of ultrathin cylindrical members made of the same material as the casing material are accommodated in a plurality of locations in the casing, A plurality of sensing rings are formed by winding more than a length corresponding to the distance resolution without fixing the optical fiber cable to each of the cylindrical members, and the temperatures of the plurality of locations are adjusted by the plurality of sensing rings. It is characterized by measuring.

  According to a third aspect of the present invention, in the optical fiber temperature sensor according to the first or second aspect, the side surface of the casing is sealed with silicon, and the entire surface of the casing is sealed with a sealing member made of a silicon-based liquid insulating material. It is characterized by doing.

  According to a fourth aspect of the present invention, in the optical fiber temperature sensor according to the second or third aspect, a spacer having the same configuration as that of the ultrathin cylindrical member is disposed so as to fill a gap of the sensing ring. .

  According to the invention of claim 1, since the casing is made of a material equivalent to the insulating material used in the induction heating device, the casing is an extremely thin sheet and the casing is an extremely thin sheet. Can be approached. For this reason, even in a poor environment and repeated thermal expansion and contraction and excessive force, the temperature at the desired position of the heating coil of the induction heating device can be constantly measured. Further, since the casing is an ultra-thin sheet, the optical fiber temperature sensor can be installed in a narrow space, is excellent in lightness, and can be easily replaced and detached during maintenance.

  According to the second aspect of the present invention, the sensing ring in which the optical fiber cable is wound without being fixed to each of the plurality of ultrathin cylindrical members can be subjected to repeated thermal expansion and contraction or excessive force. The temperature can be measured without disconnecting the optical fiber cable. Moreover, the temperature of the desired position of the heating coil surface can be measured by a plurality of sensing rings.

  According to the third aspect of the present invention, since the side surface of the casing is sealed with silicon and the entire surface of the casing is sealed with the sealing member made of a silicon-based liquid insulating material, the invasion of scale and deske water can be prevented.

  According to the invention of claim 4, since the spacer having the same configuration as the ultra-thin columnar material is disposed so as to fill the gap of the sensing ring, the optical fiber temperature sensor itself is not damaged even if it receives excessive force, The temperature can be measured without disconnecting the optical fiber cable.

It is a perspective view which shows the edge heater which installed the optical fiber temperature sensor concerning Example 1 of this invention. It is a figure which shows the internal structure of the optical fiber temperature sensor concerning Example 1 of this invention. It is sectional drawing of the optical fiber temperature sensor concerning Example 1 of this invention. It is a figure which shows the actual measurement data by the optical fiber temperature sensor concerning Example 1 of this invention. It is a perspective view which shows the bar heater which installed the optical fiber temperature sensor concerning Example 2 of this invention. It is a figure which shows the internal structure of the optical fiber temperature sensor concerning Example 2 of this invention. It is a block diagram showing a temperature distribution measuring device using the optical fiber temperature sensor of the present invention. It is a block diagram which shows the modification of the edge heater which installed the optical fiber temperature sensor concerning Example 1 of this invention.

  Hereinafter, embodiments of an optical fiber temperature sensor of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view showing an edge heater provided with an optical fiber temperature sensor according to Embodiment 1 of the present invention. In FIG. 1, a heating coil 2 and a heat-resistant plate 3 are arranged to face each other on the lower surface of a rough bar 1 made of a plate material, and an elliptical edge heater is disposed between the heating coil 2 and the heat-resistant plate 3. An optical fiber temperature sensor 4 is arranged.

 As shown in FIG. 2, the optical fiber temperature sensor 4 is formed with a housing hole 8a, and the elliptical radial iron core 6 shown in FIG. 1 is inserted into the housing hole 8a. The heating coil 2, the heat-resistant plate 3, and the optical fiber temperature sensor 4 are disposed below the concave portion of the C-type iron core 5. A heating coil 2, a heat-resistant plate 3 (not shown), and an optical fiber temperature sensor 4 (not shown) are also arranged on the upper portion of the concave portion of the C-type iron core 5. That is, two optical fiber temperature sensor units are arranged. The shield cover 7 covers the heating coil 2, the heat-resistant plate 3, the optical fiber temperature sensor 4, the C-type iron core 5, and the radial iron core 6.

 In the edge heater shown in FIG. 1, a magnetic field is generated by passing a current through the heating coil 2, and a magnetic closed loop is formed by the C-type iron core 5 and the radial iron core 6 by this magnetic field. Thus, the coarse bar 1 is heated.

 The best shape of the edge heater optical fiber temperature sensor 4 is an ellipse. This is because the edge heater is mainly composed of the heating coil 2 and the heat-resistant plate 3, the C-type iron core 5, the radial iron core 6, and the shield cover 7, but the heating coil has a shape surrounding the elliptical radial iron core 6. This is because the edge heater optical fiber temperature sensor 4 is disposed between the heating coil 2 and the heat-resistant plate 3.

  FIG. 2 is a diagram showing the internal structure of the edge heater optical fiber temperature sensor 4. FIG. 3 is a cross-sectional view of an optical fiber temperature sensor according to the present invention.

  The edge heater optical fiber temperature sensor 4 has a casing, and the casing is made of an elliptical ultra-thin sheet using a material equivalent to an insulating material used in the induction heating device. The housing is formed of a housing top surface 8, a housing bottom surface 9, a housing side surface 10, and a housing hole 80, and houses the optical fiber cable 13 therein. As the casing, a glass epoxy resin laminate is used.

  A silicon sealing 11 is applied to the side surface 10 of the casing by a silicon sealing material. The entire surface of the housing is sealed with a sealing member 12 made of a silicon-based liquid insulating material.

  A plurality of ultrathin cylindrical members 14 made of the same material as the housing material are housed in a plurality of locations in the housing. A plurality of sensing rings 15 are formed on each of the plurality of ultrathin cylindrical members 14 by winding the optical fiber cable 13 to a length corresponding to the distance resolution without fixing the optical fiber cable 13. Is used to measure the temperature at a plurality of locations of the heating coil 2.

  In addition, a circular spacer 16 having the same configuration and the same material as the ultrathin cylindrical member 14 is disposed so as to fill the gap of the sensing ring 15.

  The heating coil 2 and the heat-resistant plate 3 are very close to each other, and the thickness of the optical fiber temperature sensor 4 is preferably as thin as possible. For this reason, thickness L2, L3 of the housing | casing upper surface 8 and the housing | casing bottom surface 9 is an ultra-thin sheet | seat of 0.5 mm, respectively. A thickness L1 of the sensing ring 15 and the circular spacer 16 is set to 1 mm as a minimum dimension necessary for winding the optical fiber cable 13. Accordingly, the total thickness of the optical fiber temperature sensor is 2 mm. The optical fiber cable 13 is wound around the ultrathin cylindrical member 14 with a slight clearance.

  FIG. 4 is a diagram showing actual measurement data obtained by the optical fiber temperature sensor according to the first embodiment of the present invention, and shows a time-series temperature change at a desired position of the heating coil 2. The edge heater optical fiber temperature sensor 4 has 22 sensing rings 15 inside the housing. As shown in FIG. 4, temperature changes can be collected at any of 22 positions between the heat-resistant plate 3 and the heating coil 2 every hour. As an operation, it is possible to predict the occurrence of aged deterioration and sudden trouble by constantly monitoring the temperature transition and grasping the tendency of the temperature change such as a rapid temperature change or a gradual temperature increase.

  Thus, according to the optical fiber temperature sensor of Example 1, it is excellent in heat resistance and insulation by using a material equivalent to the insulating material used for the induction heating device, and the case is an extremely thin sheet. Therefore, it can be made very close to the heating coil. Further, since the casing is an ultra-thin sheet, the optical fiber temperature sensor can be installed in a narrow space, is excellent in lightness, and can be easily replaced and detached during maintenance.

  In addition, the optical fiber cable 13 is disconnected even when subjected to repeated thermal expansion and contraction or excessive force due to the sensing ring 15 wound without fixing the optical fiber cable 13 to the ultrathin cylindrical member 14. Temperature can be measured without any problems. Further, the temperature at a desired position on the heating coil surface can be measured by the plurality of sensing rings 15.

  Further, the side surface of the casing is sealed with silicon, and the entire surface of the casing is sealed with the sealing member 12 made of a silicon-based liquid insulating material, so that intrusion of scale and deske water can be prevented.

  Further, since the circular spacer 16 having the same configuration as that of the ultrathin columnar material is disposed so as to fill the gap of the sensing ring 15, the optical fiber temperature sensor itself is not damaged even if an excessive force is applied, and the optical fiber cable 13 Temperature can be measured without disconnection.

  FIG. 5A is a perspective view showing a bar heater provided with an optical fiber temperature sensor according to Embodiment 2 of the present invention. FIG.5 (b) is sectional drawing of the optical fiber temperature sensor concerning Example 2 of this invention.

  In Example 2 shown in FIG. 5, four flat optical fiber temperature sensors 4a to 4d are sequentially arranged in the longitudinal direction of the heating coil 2a on the inner lower surface side of the box-shaped heating coil 2a. A heat-resistant plate 3 a is disposed on the upper surfaces of the optical fiber temperature sensors 4 a to 4 d, and the heat-resistant plate 3 a covers the coarse bar 1.

 The shape of the bar heater optical fiber temperature sensors 4a to 4d is preferably a flat surface. This is because the bar heater is formed of a wound heating coil 2a, but the surface facing the rough bar 1 has a flat shape, and the bar heater optical fiber temperature sensor 4a is between the heating coil 2a and the heat-resistant plate 3a. This is because ˜4d is arranged.

  In the case of a bar heater, the width of the wound heating coil must be larger than the width of the coarse bar 1 and has a width of about 2 m. For example, four optical fiber temperature sensors 4a to 4d having a width dimension of 500 mm are arranged as a plurality of bar heater optical fiber temperature sensors 4 in order to arrange them at the width of the lower surface of the heating coil 2 having a width of 2 m. Be placed. This facilitates maintenance and handling such as replacement.

  FIG. 6 is a diagram showing the internal structure of the optical fiber temperature sensor according to the second embodiment of the present invention. The cross section of the optical fiber temperature sensor shown in FIG. 6 is the same as that of the edge heater optical fiber temperature sensor 4 shown in FIG.

  A silicon sealing 11a is applied to the side surface of the casing by a silicon sealing material. The entire surface of the housing is sealed with a sealing member 12 made of a silicon-based liquid insulating material.

  A plurality of ultrathin cylindrical members 14a made of the same material as the housing material are accommodated in a plurality of locations in the housing. A plurality of sensing rings 15a are formed in each of the plurality of ultrathin cylindrical members 14a by winding the optical fiber cable 13a to a length equal to or greater than the distance resolution without fixing the optical fiber cable 13a. Measure the temperature at multiple locations.

  Further, a circular spacer 16a having the same configuration and the same material as the ultrathin columnar material is disposed so as to fill the gap of the sensing ring 15a.

  The heating coil 2a and the heat-resistant plate 3a are very close to each other, and the thickness of the optical fiber temperature sensor is preferably as thin as possible. For this reason, the thicknesses of the housing upper surface 8a and the housing bottom surface 9a are ultra-thin sheets each having a thickness of 0.5 mm. The thickness of the sensing ring 15a and the circular spacer 16a is set to 1 mm as the minimum dimension required for winding the optical fiber cable 13a. Accordingly, the total thickness of the optical fiber temperature sensor is 2 mm. The optical fiber cable 13a is wound around the ultrathin cylindrical member 14a with a slight clearance.

  FIG. 7 is a block diagram showing a temperature distribution measuring apparatus using the optical fiber temperature sensor of the present invention. A temperature distribution measurement process using an optical fiber temperature sensor will be described with reference to FIG. The temperature distribution measuring apparatus includes a pulse generator 21, a light source 22, a light spectrometer 23, a light receiver 24, a data processing unit 25, and a data display unit 26.

  The pulse generator 21 generates a pulse signal and outputs the pulse signal to the light source 22. The light source 22 outputs an optical signal corresponding to the pulse signal from the pulse generator 21 to the optical spectrometer 23. The optical spectrometer 23 outputs the optical signal from the light source 22 to the four optical fiber cables 13a to 13d. Each of the four optical fiber cables 13a to 13d is an optical fiber cable having the configuration shown in FIG. 6, and includes optical fiber temperature sensors 4a to 4d.

  Therefore, the optical spectrometer 23 sends optical signals to the four optical fiber cables 13 a to 13 d and outputs optical signals sent from the four optical fiber cables 13 a to 13 d to the light receiver 24. The data processing unit 25 measures the temperature distribution at a desired position on the heating coil surface based on the temperature information of the optical fiber temperature sensors 4a to 4d included in the optical fiber cables 13a to 13d based on the optical signal from the light receiver 24, and displays the data. The unit 26 displays a temperature distribution at a desired position on the heating coil surface.

  FIG. 8 is a block diagram showing a usage example of the optical fiber temperature sensor for edge heater according to the first embodiment of the present invention. In FIG. 8, four units that are opposed to the front, rear, left, and right are shown as the basic arrangement of the edge heaters in the hot rolling line for steel. Four C-type iron cores 5a to 5d are arranged, and coarse bars 1a are inserted into the C-type iron cores 5a, 5b, 5c, and 5d. The C-type iron core 5a and the C-type iron core 5c are arranged so that the concave portions face each other, and the C-type iron core 5b and the C-type iron core 5d are arranged so that the concave portions face each other.

 Each of the C-type iron cores 5a to 5d has a rough bar 1a sandwiched between the lower side heating coils 2a1 to 2d1 and the lower side heat resistant plates 3a1 to 3d1, and the upper side heating coils 2a2 to 2d2 and the upper side heat resistant plate. It is possible to arrange | position the optical fiber temperature sensor for edge heaters between 3a2-3d2. That is, eight optical fiber temperature sensors can be arranged.

 For example, by connecting four optical fiber temperature sensors arranged on the lower side of the C-type iron cores 5a to 5d to the output side of the optical spectrometer 23 shown in FIG. 7, the temperature distribution at a desired position on the heating coil surface Can be measured.

  The present invention is applicable to an induction heating apparatus operated in a hot rolling line for steel.

DESCRIPTION OF SYMBOLS 1 Coarse bar 2 Heating coil 3 Heat-resistant plate 4 Optical fiber temperature sensor 5 for edge heaters C type iron core 6 Radial iron core 7 Shield cover 8 Housing upper surface 9 Housing bottom surface 10 Housing side surface 11 Silicon sealing 12 Sealing member 13 Optical fiber cable 14 Ultrathin cylindrical material 15 Sensing ring 16 Circular spacer 17 Actual measurement data 80 Housing hole

Claims (4)

An optical fiber temperature sensor installed in an induction heating device installed in a hot rolling line for steel,
An optical fiber temperature sensor characterized in that an optical fiber cable is housed in a housing made of an ultra-thin sheet using a material equivalent to an insulating material used in the induction heating device.   A plurality of ultrathin cylindrical members made of the same material as the housing material are housed in a plurality of locations in the housing, and distance resolution can be achieved without fixing the optical fiber cable to each of the plurality of ultrathin cylindrical members. The optical fiber temperature sensor according to claim 1, wherein a plurality of sensing rings are formed by winding more than a corresponding length, and temperatures of the plurality of locations are measured by the plurality of sensing rings.   3. The optical fiber temperature sensor according to claim 1, wherein a side surface of the housing is sealed with silicon, and the entire surface of the housing is sealed with a sealing member made of a silicon-based liquid insulating material.   The optical fiber temperature sensor according to claim 2 or 3, wherein a spacer having the same configuration as that of the ultrathin columnar material is disposed so as to fill a gap of the sensing ring.

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