JP2010091288A - Optical fiber temperature measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber temperature measuring instrument for accurately and stably measuring the surface temperature of a temperature measuring object by surely cooling optical fiber and a light receiver in a casing without lowering the surface temperature of the measuring object, easy in countermeasures against heat, with excellent maintainability. <P>SOLUTION: A heat-resistant protective tube 3 axially extending in the casing 1 is coupled to the end side of the casing 1 to project from the end of the casing. Discharge holes for discharging cooling gas to the exterior of the protective tube 3 are provided through a tube wall of a portion of the protective tube 3 projecting from the end of the casing, the gas flowing from openings 1a on the end of the casing into the protective tube 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a temperature measuring device using an optical fiber, and more particularly to an optical fiber temperature measuring device suitable for measuring the surface temperature of a roll in a furnace such as an electric furnace.

When measuring the surface temperature of a high-temperature heated object such as a roll in an electric furnace or the like, change to a temperature measuring device that measures the temperature by pressing a thermocouple that has been widely used in the past. In recent years, temperature measuring apparatuses using optical fibers that measure a stable and accurate temperature in a short measurement time have become common.
This type of temperature measurement device using an optical fiber is used for detecting an optical fiber and a radiant heat provided at the tip of the optical fiber in a cylindrical casing from a through hole (view hole) provided in the furnace wall. A probe equipped with a light receiving part is inserted into the furnace, and only the tip of the casing is brought into contact with the object to be heated, while the light receiving part is in a non-contact state to measure the surface temperature of the object to be heated. Yes.
Here, in this type of temperature measuring device, the temperature inside the furnace reaches a high temperature of about 1200 ° C., whereas the light receiving part and the optical fiber have a relatively low heat resistant temperature (the heat resistant temperature of the light receiving part). Therefore, for example, as shown in Patent Document 1, in order to cool the light receiving portion and the optical fiber, cooling air is supplied from the base end side to the tip end side inside the casing, and the casing In general, the cooling air is discharged from the measurement opening at the tip.

However, since all of the cooling air is discharged from the opening at the front end of the casing, when the temperature is measured by bringing the front end of the casing into contact, the air is cooled to the temperature measurement target portion on the surface of the heated body. As a result, there has been a great problem that the accurate surface temperature of the heated object cannot be measured. On the other hand, since the cooling of the light receiving unit and the optical fiber may not be sufficiently performed if the amount of cooling air supplied is reduced in order to prevent a decrease in the surface temperature of the temperature measurement target portion of the heated object, the light receiving unit In addition, it has been desired to enable stable and reliable measurement without lowering the temperature of the temperature measurement target portion of the heated object while sufficiently cooling the optical fiber.
In addition, as described above, the temperature inside the furnace is very high, so countermeasures against heat are inevitable. However, from the viewpoint of facilitating countermeasures against heat and ensuring maintainability, the light receiving unit and the optical fiber are cooled. It is important to reduce the number of parts as much as possible and to simplify the entire structure when realizing both the prevention of the temperature decrease of the heated object.

JP-A-6-109547

The technical problem of the present invention is to reliably cool the optical fiber and the light receiving part in the casing without lowering the surface temperature of the temperature measurement target part, and accurately and stably measure the surface temperature of the measurement target part. An object of the present invention is to provide an optical fiber temperature measuring device that can perform the above-described process.
Another technical problem of the present invention is to provide an optical fiber temperature measuring device that is easy to take measures against heat and excellent in maintainability.

  In order to solve the above-mentioned problems, an optical fiber temperature measuring device according to the present invention is provided with a cylindrical casing having an opening at a distal end, the casing is provided with a proximal end side connected to a temperature measuring instrument, and a distal end side. An optical fiber having a light receiving portion for detecting radiant heat and an optical fiber temperature measuring device configured to supply a cooling gas into the casing and discharge the gas from an opening at the front end of the casing. The heat-resistant protective cylinder extending in the axial direction of the casing is connected so as to protrude from the casing front end, and the cylinder wall of the portion protruding from the casing front end of the protective cylinder is connected to the inside of the protective cylinder from the opening at the casing front end. A discharge hole for discharging the cooling gas flowing into the outside of the protective cylinder is provided.

In the present invention, the protective cylinder may be connected to the casing in a state where the distal end side of the casing is fitted to the proximal end side in the protective cylinder.
In this case, the protective cylinder is connected to the casing in a non-removable manner by a plurality of fixing bolts that pass through the protective cylinder and the casing in a direction perpendicular to the axial direction of the protective cylinder and the casing. It is preferable that the optical fiber is held in the casing by being sandwiched between the tip portions of the screw rods in these fixing bolts.

According to the present invention, the heat-resistant protective cylinder is connected to the front end of the casing containing the optical fiber and the light receiving portion so as to protrude from the front end of the casing, and the cylindrical wall of the portion of the protective cylinder that protrudes from the front end of the casing Is provided with a discharge hole, and the cooling gas flowing into the protective cylinder from the opening at the tip of the casing is discharged to the outside of the protective cylinder. Therefore, the optical fiber and the light receiving portion in the casing are for cooling. While being reliably cooled by the gas, most of the cooling gas that has flowed into the protective cylinder from the front end of the casing is discharged out of the protective cylinder through the discharge hole before contacting the temperature measurement target portion of the heated body. Therefore, the surface temperature of the part to be measured can be accurately and stably measured without reducing the surface temperature of the part to be measured.
In addition, it has a very simple structure by simply connecting the heat-resistant protective cylinder provided with the discharge hole at the end of the casing, and since the number of parts is very small, it is extremely easy to take measures against heat and has excellent maintainability. .

  FIGS. 1 to 3 show an embodiment of an optical fiber temperature measuring device of the present invention. The temperature measuring device of this embodiment has a cylindrical casing 1 having an opening 1a for temperature measurement at the tip. And an optical fiber 2 provided in the casing 1 and having a light receiving portion 2a for detecting radiant heat attached to the front end side, and a heat-resistant protective cylinder 3 connected to the front end of the casing 1. .

The casing 1 is formed in a substantially cylindrical shape that is long in the axial direction, the opening 1a is provided on the distal end side, and a lead-out hole for hermetically leading the proximal end side of the optical fiber 2 on the proximal end side. An optical fiber blocking member 4 having 4 is attached.
In addition, an air supply pipe portion 5 for supplying cooling air into the casing 1 is integrally connected to the vicinity of the base end of the casing 1 in a state inclined toward the base end side of the casing 1. The space inside the pipe of the air supply pipe 5 and the space in the cylinder of the casing 1 are in an airtight communication state, and the air is at the base end in the casing 1 at the time of temperature measurement or immediately after the end of the measurement. It is configured to be constantly supplied from the side toward the tip side. The tip of a tube (not shown) for supplying air is placed in the air supply pipe 5 at the tip of the air supply pipe 5 (the end opposite to the connecting portion with the casing 1). A tube closing member 6 having an inlet 6a for airtight introduction is attached.

The optical fiber 2 includes the light receiving unit 2a including a lens that collects radiated light from the heated object at the distal end side, while the base end side has a temperature based on the radiated light transmitted from the optical fiber 2. Is connected to a temperature measuring device (not shown) that measures and displays
The optical fiber 2 is held substantially at the center in the casing 1 by being sandwiched between screw rods 9a and 9a tip portions of a pair of fixing bolts 9 and 9, which will be described later, and the optical fiber 2 and the light receiving portion 2a are It is comprised so that it may not contact the cylinder wall of the casing 1. FIG. As a result, the cooling air is smoothly circulated around the outer periphery of the optical fiber 2 and the light receiving portion 2a in the casing 1, and the heat transmitted from the heated object or the furnace atmosphere to the casing 1 is as much as possible to the optical fiber 2 or the light receiving portion. It is prevented from being transmitted to the part 2a.
In addition, since the temperature measurement technique itself using an optical fiber is well known, detailed description of the measurement principle and the like is omitted.

The heat-resistant protective cylinder 3 is a cylindrical member formed of a material having excellent heat resistance such as ceramic and extending in the axial direction of the casing 1. The probe is inserted into a furnace such as an electric furnace together with the casing 1. 7 is constituted.
The protective cylinder 1 is formed separately from the casing and has an inner diameter substantially the same as the outer diameter of the casing 1, and the distal end portion of the casing 1 is fitted into the protective cylinder 3 from the base end side into the cylinder. When the protection tube is replaced when it has deteriorated due to the influence of heat, etc., the protection tube can be easily removed and attached by inserting and removing the casing from the protection tube. Yes.
Furthermore, the protective cylinder 3 is connected to the casing 1, and the front end side protrudes from the front end of the casing 1, and the cylindrical wall of the protruding portion is formed on the front end of the casing after cooling the inside of the casing 1. A discharge hole 8 for discharging cooling air flowing into the protective cylinder 3 from the opening 1a to the outside of the protective cylinder is provided.

As shown in FIGS. 1 and 2, a plurality of the discharge holes 8 are provided in each of the upper and lower portions of the protective cylinder 3 in the figure, and the four side cylinder walls located on the left and right sides (in the case of this embodiment, The three discharge holes 8 are formed in a direction perpendicular to the axis of the protective cylinder 3.
In addition, as shown in FIG. 1, these discharge holes 8 are disposed closer to the base end side (the direction away from the distal end) of the protruding portion of the protective cylinder 3 as a whole, and the air that has flowed into the protective cylinder 3 Is configured to be discharged to the outside at a position as far as possible from the heated body so as to suppress the influence of air on the heated body as much as possible.

  Specifically, with respect to the protective cylinder 3 and the discharge hole 8, when the axial length of the casing is about 1450 mm, the protruding portion of the protective cylinder 3 from the casing 1 is about 100 mm. Desirably, the discharge hole 8 is provided at the most distal position at a position about 30 mm away from the tip of the protective cylinder 3 and thereafter provided at intervals of 30 mm. The discharge holes 8 having a diameter of about 2 mm are preferably arranged linearly in the upper, lower, left and right rows of the cylinder wall of the protective cylinder.

  By the way, as shown in FIG. 1, the protective cylinder 3 and the casing 1 are formed in a state in which the distal end side of the casing 1 is fitted into the protective cylinder 3 from the proximal end side of the protective cylinder 3 and The protective cylinder 3 is fixed to each other so that it cannot be removed from the casing 1 by a plurality of fixing bolts penetrating in a direction orthogonal to the axial direction of the casing 1. And the optical fiber 2 is always hold | maintained in the state which does not contact the cylinder wall of the casing 1 by pinching | interposing the said optical fiber 2 with the front-end | tip part of the screw rod in these fixing bolts. Therefore, the fixing bolt has both functions of securely fixing the protective cylinder 3 to the casing 1 and holding the optical fiber 2 in the casing 1, thereby simplifying the overall configuration. In addition, the number of parts can be reduced, the maintainability can be further improved, and the manufacturing cost can be further reduced.

In this embodiment, as shown in FIGS. 1 and 3, fixing bolts 9 and 9 are removably screwed into the upper and lower portions of the protective cylinder 3 in the drawing. The optical fiber 2 is sandwiched from above and below by the tip portions of the screw rods 9a, 9a of these two fixing bolts 9, 9. Further, bolt holes 3a and 1b penetrating through the respective cylinder walls of the protective cylinder 3 and the casing 1 in the vertical direction are provided in the upper and lower portions of the protective cylinder 3 and the casing 1, respectively. Is configured to be detachably screwed so as to penetrate through the cylindrical walls of the protective cylinder 3 and the casing 1.
Further, in this embodiment, as shown in FIG. 1, apart from the fixing bolts 9 and 9, in the vicinity of the proximal end side of the protective cylinder, a screw rod penetrates the protective cylinder and the casing and is connected to the optical fiber. The two auxiliary bolts 10 and 10 formed in such a length that they do not come into contact with each other are screwed from above and below the protective cylinder and the casing, respectively, so that the protective cylinder can be more securely fixed to the casing. I have to. In this embodiment, the protective cylinder 3 can be removed from the casing 1 by removing all the fixing bolts 9 and 9 and the auxiliary bolts 10 and 10.

An optical fiber temperature measuring device having the above-described configuration is such that, for example, a probe 7 is inserted into a furnace through a peephole provided in a furnace wall of an electric furnace or the like, and the tip of the protective cylinder 3 is brought into contact with a heated object such as a roll. The light receiving unit 2a receives light from the object to be heated, calculates the temperature with a temperature measuring device based on the radiated light transmitted through the optical fiber 2, and displays the temperature. At the time of measurement, cooling air is constantly supplied into the casing 1, and as shown by arrows in FIG. 1, the air circulates in the casing 1 to cool the optical fiber 2 and the light receiving unit 2a. It is discharged from the opening 1a at the front end of the casing.
At this time, the heat-resistant protective cylinder 3 is connected to the front end of the casing 1 so as to protrude from the front end of the casing 1, and a plurality of discharge holes 8 are formed in the cylindrical wall of the portion of the protective cylinder 3 protruding from the front end of the casing. Since the cooling air that has flowed into the protective cylinder 3 from the openings 1a through the discharge holes 8 is discharged outside the protective cylinder 3, the air discharged from the front end of the casing is protected. While flowing into the cylinder 3, the air is discharged out of the protective cylinder 3 through the discharge hole 8 before contacting the temperature measurement target portion of the heated body.
Therefore, not only can the optical fiber 2 and the light receiving unit 2a in the casing 1 be reliably cooled by the cooling air, but also the surface temperature of the temperature measurement target part is not lowered. And it can measure stably.

  Furthermore, since the optical fiber temperature measuring device has a very simple configuration in which only the heat-resistant protective cylinder 3 provided with the discharge hole 8 is connected to the tip of the casing 1, various components, particularly the influence of heat are most affected. Since the protection cylinder 3 to be received can be easily checked or replaced, it is excellent in maintainability. In addition, since the number of parts is very small, it is possible to take a countermeasure against heat for each part relatively easily. Therefore, the countermeasure against the heat of the entire apparatus is very easy, and the manufacturing cost can be reduced.

  In the above embodiment, an example of measuring the surface temperature of the roll in the furnace of the electric furnace has been described. However, the present invention is not limited thereto, and is suitable for measuring the surface temperature of various rolls used for rolling and the like. It can be used for measurement of the surface temperature of a heated object.

  In the above-described embodiment, three discharge holes 8 are linearly arranged in each of the upper, lower, left, and right rows of the protective cylinder 3, and a total of twelve holes are provided. In consideration of the effects of heat, any number may be provided as long as the rigidity of the protective cylinder is ensured and reliable discharge according to the cooling gas supply amount is possible. The arrangement and diameter can be set as appropriate.

  Further, in the above embodiment, the discharge hole 8 is formed in a direction perpendicular to the axis of the protective cylinder, but the discharge hole is formed in a direction inclined toward the proximal end side of the protective cylinder. In this case, since the air from the discharge hole is discharged in a direction away from the object to be heated, the air can be prevented from coming into contact with the object to be heated, and is given to the object to be heated. It is possible to more reliably eliminate the influence of air.

In the above embodiment, two (one pair) fixing bolts 9, 9 are screwed in from the upper and lower sides of the protective cylinder and the casing 1, respectively, and the protective cylinder 3 is fixed to the casing 1 and the optical fiber is sandwiched at one place. However, the protection cylinder may be fixed to the casing and the optical fiber may be sandwiched simultaneously at a plurality of locations using a plurality of pairs of fixing bolts.
Further, it is not always necessary to fix the protective cylinder to the casing and sandwich the optical fiber with two fixing bolts, and three or more fixing bolts may be used.
When the optical fiber is held in the casing using an appropriate means such as another metal fitting or when it is not necessary to hold the optical fiber, it is not always necessary to sandwich the optical fiber with the fixing bolt.

  Further, in the above embodiment, apart from the fixing bolts 9, 9, the two auxiliary bolts 10, 10 are screwed from above and below the protective cylinder and the casing 1 on the proximal end side of the protective cylinder 3. However, one or three or more auxiliary bolts can be disposed at appropriate positions as long as the protective cylinder can be securely fixed to the casing. Note that the auxiliary bolt itself is not necessarily provided and can be omitted.

Moreover, in the said embodiment, although it has set it as the structure which connects the protection cylinder 3 to the casing 1 by making the front end side of the casing 1 fit in the inside of the base end side of the protection cylinder 3, it is not restricted to this, A protection cylinder It is good also as a structure which connects these protection cylinders and a casing mutually by inserting the base end side of this into the inside of this casing from opening of a casing front-end | tip.
If replacement of the protective cylinder is unnecessary, the proximal end side of the protective cylinder and the distal end side of the casing may be fixed to each other by welding or the like. In this case, the fixing bolt is omitted. can do.

  Furthermore, in the said embodiment, although air is used as a gas for cooling, other inert gas etc. can also be used and an appropriate gas can be selected.

It is sectional drawing which shows one Embodiment of the optical fiber temperature measuring apparatus which concerns on this invention. However, the temperature measuring device is omitted. It is an AA expanded sectional view of FIG. It is BB expanded sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Casing 1a Opening 2 Optical fiber 2 Light-receiving part 3 Heat-resistant protective cylinder 8 Ejection hole 9 Fixing bolt 9a Screw rod

Claims (3)

A cylindrical casing having an opening at the tip, an optical fiber provided in the casing, the base end side being connected to a temperature measuring device, and a light receiving portion for detecting radiant heat attached to the tip end side, and the casing In the optical fiber temperature measuring device configured to supply a cooling gas into the casing and discharge from the opening at the tip of the casing,
A heat-resistant protective cylinder that extends in the axial direction of the casing is connected to the front end side of the casing so as to protrude from the front end of the casing. An optical fiber temperature measuring device, wherein a discharge hole for discharging the cooling gas that has flowed into the protective cylinder from the opening of the protective cylinder is provided outside the protective cylinder.   The optical fiber temperature measuring device according to claim 1, wherein the protective cylinder is connected to the casing in a state in which a distal end side of the casing is fitted to a proximal end side in the protective cylinder.   The protective cylinder is non-detachably connected to the casing by a plurality of fixing bolts that pass through the protective cylinder and the casing in a direction perpendicular to the axial direction of the protective cylinder and the casing, and the optical fiber is The optical fiber temperature measuring device according to claim 2, wherein the optical fiber temperature measuring device is held in the casing by being sandwiched between the tip portions of the screw rods in the fixing bolts.

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