JPH09105675A - Temperature measuring apparatus for molten material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature measuring apparatus for a molten material which makes it possible to suppress the excess insertion of the end of the fiber into the material and advantageous to suppress the consumption of optical fiber. SOLUTION: The temperature measuring apparatus measures the temperature of a molten material M by passing the light from the material through an optical fiber 3. The apparatus comprises a moving unit 2 approachable to the molten material surface of the material M, a float 5 floated in contact with the molten material surface of the material M upon approaching of the unit 2, the fiber 3 retracted at the end 3k to the retracting position Ha of the float 5, molten material surface contact detecting means 8 for detecting the contact of the float 5 with the molten material surface of the material M, and an optical fiber conveying means 6 for advancing the fiber 3 on the basis of the detection of the means 8 to bring the end 3k into contact with the surface of the material M.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature measuring device for molten material. The device of the present invention can be used when measuring the temperature of a molten material such as a cast iron melt or an aluminum melt.

[0002]

2. Description of the Related Art Conventionally, there has been known a technique of measuring the temperature of a molten material by passing light from the molten material through an optical fiber. Specifically, in Japanese Unexamined Patent Publication No. 61-243331, in measuring the temperature of an aluminum-based molten metal by using an optical fiber, the optical fiber is sandwiched by a pair of rollers, and the optical fibers are continuously rotated while rotating the rollers with a drive motor. The present applicant has disclosed a technique of measuring the temperature of the molten metal based on the infrared rays of the aluminum-based molten metal that has been transmitted through the optical fiber by inserting it into the molten metal surface of the molten metal.

When the optical fiber comes into contact with the molten material at high temperature, the optical fiber is thermally deteriorated, which may cause deterioration of temperature measurement accuracy.
However, according to the technique disclosed in the above publication, since the optical fiber is continuously inserted into the molten metal and immersed therein, it is advantageous to prevent a decrease in temperature measurement accuracy due to thermal deterioration of the tip of the optical fiber.

[0004]

According to the technique disclosed in the above publication, since the optical fiber is continuously inserted into the molten metal during temperature measurement, the temperature measurement accuracy is lowered due to the thermal deterioration of the tip of the optical fiber. Although this can be prevented, the tip of the optical fiber tends to be excessively inserted into the molten metal, resulting in severe wear of the optical fiber.

The present invention is intended to improve the technique according to Japanese Patent Application Laid-Open No. 61-243331 using the above-mentioned optical fiber, and its problem is to insert the tip of the optical fiber excessively into the molten material. Another object of the present invention is to provide a temperature measuring device for a molten material which can be suppressed and which is advantageous in suppressing the consumption of the optical fiber.

[0006]

A molten material temperature measuring device according to the present invention is a molten material temperature measuring device for measuring the temperature of a molten material by passing light from the molten material through an optical fiber. A movable body that can approach and separate from the molten metal surface, a float that is equipped on the movable body and floats in contact with the molten metal surface when the movable body approaches, and can transmit light from the molten material In addition, when the temperature is not measured, the tip of the optical fiber whose tip is retracted to the retracted position of the tip of one of the float and the movable body, and the melt contact detection means for detecting that the float has contacted the melt surface of the molten material And an optical fiber conveying means for advancing the optical fiber by a predetermined distance based on the detection of the molten metal contact detection means, and for bringing the tip of the optical fiber into contact with the molten metal surface for temperature measurement of the molten material. The one in which the features.

[0007]

According to the device of the present invention, the tip of the optical fiber is normally retracted to the retracted position of the fiber tip of the float and the moving body in order to prevent thermal deterioration. On the other hand, when measuring the temperature of the molten material, the moving body approaches the molten metal surface. As the moving body approaches, the float equipped on the moving body contacts the molten metal surface and floats. The contact of the float with the surface of the molten material is detected by the surface contact detecting means. Based on the detection by the molten metal contact detection means, the optical fiber conveying means advances the optical fiber by a predetermined distance to bring the tip of the optical fiber into contact with the molten metal surface of the molten material. In this state, the light from the molten material passes through the optical fiber, and the temperature of the molten material is measured by the temperature measuring means.

Any temperature measuring means may be used as long as it can measure the temperature based on the light transmitted from the molten material through the optical fiber, and generally, a method of detecting the brightness of the molten material can be adopted. The above-mentioned moving body can be composed of a horizontal moving unit and a lifting unit.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. (Structure) As shown in FIG. 1, a melting furnace 1 holding an iron-based or aluminum-based molten metal M as a molten material is provided. A furnace lid 10 having a temperature measurement opening 11 is attached to the melting furnace 1. An installation table 13 is provided near the melting furnace 1.

The movable body 2 is arranged on the installation base 13. The moving body 2 is a fixed arm 2 fixed to the installation base 13.
0, a horizontal swivel arm 21 provided horizontally on the fixed arm 20, that is, movable in the directions of arrows X1 and X2, a base 22 held by the horizontal swivel arm 21, and a base 22 that can be moved up and down, that is, in the directions of arrows Y1 and Y2. The lifting block 23 is provided so as to be movable, and a vertically oriented guide tube 24 integrally held by the lifting block 23. Guide tube 24
Guides the optical fiber 3, and the optical fiber 3 is inserted into the central hole thereof.

The temperature detecting means 4 includes a temperature sensor 40 for generating a temperature signal based on the brightness of the light of the molten metal M transmitted through the optical fiber 3, a signal processing circuit 41 for processing the detection signal of the temperature sensor 40, and a temperature sensor. The temperature display unit 42 displays the molten metal temperature based on the detection signal of 40. Further description will be added with reference to FIG. As can be seen from FIG. 3, the base 22 holds a rodless cylinder 25. Vertical guide rails 2 on both sides
6 are fixed in a juxtaposed state. Rodless cylinder 2
5 is a float 5 described below in the vertical direction, that is, in the Y1 direction, Y
It functions as a Y-direction drive source for driving in two directions. The end 23i of the elevating block 23 has a guide rail 26.
Is engaged in a guide manner. An elevating block 23 is placed on a movable part 25c of the rodless cylinder 25 that can be moved up and down.

When the rodless cylinder 25 operates, the movable portion 25c moves up and down in the directions of arrows Y1 and Y2. Therefore, the lifting block 23 moves the guide rail 26 in the directions of the arrows Y1 and Y2.
The guide tube 24 held by the elevating block 23 also ascends and descends in the same direction. The elevating block 23 holds the optical fiber conveying means 6. The optical fiber transporting means 6 includes a pair of pinch rollers 60 rotatably held by the elevating block 23, and a drive motor 61 for driving the pinch rollers 60. When the pinch roller 60 rotates in the direction of arrow C1 (see FIG. 3A), the optical fiber 3 advances in the direction of arrow Y2 and the tip 3k of the optical fiber 3 is inserted into the molten metal M. on the other hand,
When the pinch roller 60 rotates in the reverse direction, the optical fiber 3 retreats in the direction of the arrow Y1 and the tip 3k thereof is detached from the molten metal M.

The optical fiber 3 is composed of a fiber body through which light from the molten metal M is transmitted, and a resin or metal coating layer covering the outer peripheral surface of the fiber body.
A float 5 made of a refractory material, which floats on the molten metal surface M1 of the molten metal M, is held at a lower end portion 24m of the guide tube 24 which is one element of the moving body 2. Inside the float 5, a hollow optical fiber insertion hole 50 having a lower surface opening 50r is formed. The optical fiber insertion hole 50 has a hemispherical shape or a substantially hemispherical shape whose diameter becomes smaller toward the upper part thereof.

In a normal state, that is, when the temperature of the molten metal M is not measured, the tip portion 3 of the optical fiber 3 is not measured.
k is retracted to the retracted position Ha of the float 5 which is the retracted position of the optical fiber tip. The height of the withdrawal position Ha is set so that the tip 3k of the optical fiber 3 is inserted into the molten metal surface M1 of the molten metal M by advancing by a predetermined distance ΔL from the withdrawal position Ha.

When the shape, material and volume of the float 5 and the material of the molten metal M are set, the weight of the float 5 and the buoyancy acting on the float 5 are specified. Therefore, the immersion depth Δh (see FIG. 3 (A)) in which the float 5 is immersed in the molten metal M has an integrated value so that the weight of the float 5 directed downward and the buoyancy of the float 5 directed upward are balanced. Stipulated.
Therefore, the distance that the optical fiber 3 advances until the tip 3k of the optical fiber 3 is inserted into the molten metal M is a predetermined distance Δ.
Specified as L.

As shown in FIG. 3B, the guide tube 24 has
A limit switch 8 that functions as a molten metal contact detection means is held. Limit switch 8 switch part 8f
Can collide with the descending movable part 25c. When the switch portion 8f collides with the movable portion 25c, the signal is input to the control device via the signal line. (Use) The operation of the apparatus of this embodiment will be described together with the method of use. When not measuring the temperature of the molten metal M,
As can be understood from FIG. 2, the horizontal swing arm 21 stands by at the stand-by position P1.

At the time of temperature measurement, the horizontal swing arm 21 at the standby position P1 is horizontally moved in the direction of arrow X1 by operating a cylinder (not shown), and the float 5 is used for measuring the temperature of the furnace lid 10 of the melting furnace 1. The temperature measurement opening 11 is made to face directly above the opening 11. Next, as can be understood from FIGS. 3A and 3B, when the rodless cylinder 25 operates and the elevating block 23 descends in the direction of the arrow Y2, the float 5 and the guide tube 24 move to the furnace lid 10.
It passes through the temperature measurement opening 11 and reaches below the furnace lid 10.

As a result, the float 5 is the molten metal surface M1 of the molten metal M.
Touch and touch to float. As the float 5 floats, the lowering of the guide tube 24 is substantially stopped. This is because when the float 5 is floating on the molten metal surface M1 of the molten metal M, the guide tube 24 cannot descend further in the direction of the arrow Y2 unless the buoyancy acting on the float 5 is overcome.

As described above, the float 5 is the melt surface M1 of the molten metal M1.
If the elevating block 23 continues to descend while floating in the movable part 2, as can be understood from FIG.
5c hits the switch portion 8f of the limit switch 8. As a result, a signal is input from the limit switch 8 to the control device, so that it is detected that the float 5 has come into contact with the molten metal surface M1 of the molten metal M.

Based on this signal, the controller stops the rodless cylinder 25. Then, the lowering of the elevating block 23 is stopped, and an ON signal for driving the drive motor 61 is output to the drive motor 61 for a predetermined time ΔT1. In this way, when the drive motor 61 is driven for ΔT1 time, the optical fiber 3 is advanced in the direction of arrow Y2 by a distance corresponding to the predetermined distance ΔL. As a result, the tip portion 3k of the optical fiber 3 is melted M
It is inserted and immersed in the molten metal surface M1.

After the lapse of ΔT1 time, the control device rotates the drive motor 61 backward for ΔT2 time, and the optical fiber 3 is retracted in the direction of the arrow Y1. Then, the tip 3k of the optical fiber 43 returns to the retracted position Ha of the float 5. When the drive motor 61 rotates forward to move the optical fiber 3 forward and ΔT1 and the drive motor 61 rotates backward to move the optical fiber 3 backward, ΔT2, according to the present embodiment, ΔT1> ΔT2, that is, ΔT1 =
It is set to ΔT2 + α. α is molten metal M and optical fiber 3
Optical fiber 3 caused by immersion of the tip 3k of the
This is because the amount of wear of the tip 3k is taken into consideration.

Therefore, according to the present embodiment, the predetermined distance for moving the optical fiber 3 toward the molten metal surface M1 of the molten metal M for the temperature measurement is set to ΔL, and the optical fiber 3 is retracted from the molten metal M surface M1 after the temperature measurement. When the retreat distance to be set is ΔL2,
ΔL> ΔL2 is set. As described above, the tip portion 3k of the optical fiber 43 has the float 5
After returning to the retreat position Ha, the rodless cylinder 25 is operated to raise the elevating block 23 in the direction of the arrow Y1 to separate the float 5 from the molten metal surface M1 and further to open the temperature measurement opening of the furnace lid 10. The guide tube 24 and the float 5 are pulled out from 11, and the float 5 is positioned above the furnace lid 10.

When the float 5 is pulled out from the temperature measuring opening 11 of the furnace lid 10, the horizontal swing arm 21 is swung in the direction of arrow X2 shown in FIG. 2 and returned to the standby position P1 for standby. This completes one cycle of the temperature measurement operation. According to this embodiment, the float 5 is suspended in the molten metal M,
While the tip portion 3k of the optical fiber 3 is being inserted into the molten metal M, the temperature of the molten metal M is measured. Then, the temperature measurement signal is peak-held by the peak hold circuit, the peak value of the temperature values measured during the above is determined as the temperature of the molten metal M, and the temperature of the molten metal M is displayed on the temperature display section 42.

(Float 5) A cross section of the float 5 used in this embodiment is shown in FIG. Further, the float 5 shown in FIG. 4 (B) may be adopted depending on the case. However, according to the float 5 shown in FIG. 4B, the optical fiber insertion hole 5 formed in the float 5
0 has a small cylindrical shape, and its inner diameter is basically the same in the hole length direction, that is, in the arrow F1 direction.

By the way, when the float 5 is taken out from the molten metal M, the molten metal M attached to the inner wall surface of the optical fiber insertion hole 50 may be solidified as it is. In this case, the optical fiber insertion hole 50 may be clogged, which may interfere with the insertion of the optical fiber 3 and the temperature measurement. In this respect, according to the float 5 shown in FIG. 4A according to the present embodiment, the optical fiber insertion hole 50 formed of a hemispherical or substantially hemispherical cavity having the lower surface opening 50r having a large opening area is formed. Has been done. Therefore, it is advantageous to increase the buoyancy with respect to the float 5, and the float 5 causes the molten metal M to increase as the buoyancy increases.
The immersion depth Δh (see FIG. 4A) becomes smaller.
Therefore, the amount of the molten metal M attached to the float 5 is reduced. Therefore, it is more advantageous to prevent the optical fiber insertion hole 50 from being clogged by the solidification of the molten metal M attached to the float 5.

As a test example, using the float 5 shown in FIG. 4A, the relationship between the diameter of the optical fiber insertion hole 50 formed in a hemispherical or substantially hemispherical cavity and the amount of molten metal adhered to the float 5 Was measured. The test result is shown as a characteristic line K1 in FIG. As can be understood from the characteristic line K1 in FIG. 5, as the diameter of the optical fiber insertion hole 50 increases, the amount of the molten metal M attached to the float 5 decreases. This is because if the diameter of the optical fiber insertion hole 50 increases, the buoyancy of the float 5 increases and the amount of immersion of the float 5 in the molten metal M decreases. According to this test, it was found that when the diameter of the optical fiber insertion hole 50 exceeds 50 mm, the adhered amount of the molten metal M is substantially eliminated. According to this test, the material of the float 5 is silica, the diameter of the float 5 is 150 mm, and the molten metal M is cast iron (for example, FC230).

(Other Example) FIG. 6 shows a float 5 according to another example.
Is shown. In this example, a male screw portion 24f is formed at the lower end of the guide tube 24. The float 5 is composed of a float main body 52 made of a refractory material and a metal (for example, steel-based) connecting tool 53 embedded in the float main body 52. The connector 53 is a fixed cylinder body 5 having a female screw portion 54f.
4 and a ring-shaped flange portion 5 embedded in the float main body 52 extending radially outward from the outer peripheral portion of the fixed cylindrical body 54.
5 is comprised. The float main body 52 is provided with an optical fiber insertion hole 50 having a hollow large volume, and an extending wall portion 57 as a conical taper portion extending obliquely. A small diameter lower surface opening 50r is defined by the tip portion 57w of the extended wall portion 57.

When the float 5 is in contact with the molten metal M,
Due to the thermal expansion of the molten metal M, the male screw portion 24f of the guide tube 24 thermally expands in the radial direction. Therefore, if the female screw portion is made of a refractory material, the difference in thermal expansion coefficient between the refractory material and the metal causes
The male screw portion 24f may bite into the female screw portion made of the refractory material and induce damage to the female screw portion made of the refractory material. In this point, according to the example shown in FIG. 6, the female screw portion 54f is formed in the metallic connector 53, and the female screw portion 5 of the metallic connector 53 is formed.
4f and the male screw portion 24f of the metal guide tube 24 are screwed together. In this way, the female screw portion 54f and the male screw portion 24f
Since both of them are made of metal and the difference in thermal expansion between them can be reduced or avoided, it is advantageous to suppress damage to the screw portion due to the difference in thermal expansion and enhance the durability of the float 5.

As shown in FIG. 6, when the slag M2 floats on the molten metal surface M1 of the melt M, the slag M2 serves as a barrier.
It is disadvantageous to insert the optical fiber 3 into the molten metal surface M1 of the molten metal M. In this point, according to the example shown in FIG. 6, when the float 5 descends to the molten metal surface M1 of the molten metal M, the inclination of the extended wall portion 57 of the float 5 facilitates concentration of stress on the slag M2. It becomes easier to destroy the slag M2, and the molten metal M
It is advantageous for exposing the molten metal surface M1.

Further, when the slanted outer wall surface 57s of the extended wall portion 57 of the float main body 52 hits the slag slag M2, it is advantageous to shift the slag slag M2 laterally, that is, in the direction of the arrow E1 by the "wedge principle". Therefore, it can further contribute to exposing the molten metal surface M1 of the molten metal M. Further, according to the example shown in FIG. 6, when the optical fiber 3 retracted to the retracted position Ha is inserted into the molten metal M, the tip portion 3k of the optical fiber 3 becomes the inclined inner wall surface 57t of the extended wall portion 57 of the float 5. Due to the descending inclination, there is an advantage that it is easily guided to the lower surface opening 50r.

(Other Example) By the way, in the above example, the limit switch 8 is employed as the molten metal surface contact detecting means for detecting that the float 5 has contacted with the molten metal surface M1 of the molten metal M. However, not limited to this, as in the example shown in FIG. 7, the buoyancy detector 58 that detects the magnitude of the buoyancy acting on the float 5 when the float 5 is floating on the molten metal surface M1 is lifted and lowered. 23 may be provided to detect the contact of the float 5 with the molten metal surface M1 of the molten metal M based on the magnitude of the buoyancy acting on the float 5.

In this case, if a force in the direction of arrow Y2 is applied to the guide tube 24 in the direction in which the float 5 floating in the molten metal M is further submerged in the molten metal M, the buoyancy acts in the direction in which the guide tube 24 is lifted. As a result, the buoyancy detector 58 (for example, a piezoelectric element or a load cell) is connected to the end 24 of the guide tube 24.
Since the pressure is strongly applied by i, the buoyancy detector 58 outputs a signal. As a result, it is detected that the float 5 has come into contact with the molten metal surface M1 of the molten metal M.

As described above, the present apparatus is an example applied to the temperature measurement of the molten metal M in the melting furnace 1, but not limited to this, as long as the temperature of the molten metal is measured using the optical fiber 3, a holding furnace or a heat retention It is also applicable when measuring the temperature of the molten metal contained in the furnace. (Supplementary Note) The following technical idea can be understood from the above-described embodiment. Set ΔL> ΔL2, where ΔL is the predetermined distance for advancing the optical fiber toward the surface of the molten material for temperature measurement and ΔL2 is the receding distance for retracting the optical fiber from the surface of the molten material after temperature measurement. The apparatus of claim 1, wherein the apparatus is: This is because the wear of the tip of the optical fiber due to the insertion into the molten material is taken into consideration. ○ When the drive time of the drive motor that advances the optical fiber toward the surface of the molten material for temperature measurement is ΔT1, and the drive time of the drive motor that retracts the optical fiber from the surface of the molten material after temperature measurement is ΔT2. , ΔT1> ΔT2. This is because the wear of the tip of the optical fiber due to the insertion into the molten material is taken into consideration. The device according to claim 1, wherein the float is provided with an optical fiber insertion hole formed with a cavity for increasing buoyancy whose opening area increases as it goes downward. The device according to claim 1, wherein the float is provided with a taper portion for facilitating breakage of the slag.

[0034]

According to the apparatus of the present invention, the tip of the optical fiber is normally retracted to the fiber tip retracted position, and the optical fiber is advanced based on the signal from the molten metal contact detection means during temperature measurement. And insert it into the molten material surface. Therefore, it is possible to prevent the tip portion of the optical fiber from being excessively inserted into the molten metal surface. Therefore, it is possible to suppress the consumption of the tip of the optical fiber due to the molten material.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing an apparatus.

FIG. 2 is a configuration diagram schematically showing a plane of the device.

FIG. 3 is a configuration diagram showing a main part of a configuration in which a float is brought into contact with a molten metal surface.

FIG. 4 is a sectional view of a float.

FIG. 5 is a graph showing the relationship between the diameter of the optical fiber insertion hole of the float and the amount of molten metal attached.

FIG. 6 is a cross-sectional view showing another float.

FIG. 7 is a configuration diagram showing another device.

[Explanation of symbols]

In the figure, M is a molten metal (molten material), M1 is a molten metal surface, Ha is a retracted position (fiber tip retracted position), 2 is a moving body, 3 is an optical fiber, 3k is a tip, 5 is a float, and 6 is an optical fiber transport. Means, 60 is a pinch roller, 61 is a drive motor, and 8 is a limit switch (metal surface contact detection means).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshikichi Yamanaka 1-2, Marunouchi, Chiyoda-ku, Tokyo Japan Steel Pipe Co., Ltd. (72) In-house Yoshiro Yamada 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Main Steel Pipe Co., Ltd.

Claims (1)

[Claims] 1. A temperature measuring device for a molten material, which measures the temperature of the molten material by passing light from the molten material through an optical fiber, comprising a movable body which can approach and separate from the molten metal surface of the molten material. A float that is equipped on the moving body and floats in contact with the molten metal surface as the moving body approaches, and allows light from the molten material to pass therethrough, and the tip portion when the temperature is not measured. An optical fiber retracted to the retracted position of the fiber tip of one of the float and the moving body, a melt level contact detection unit that detects that the float has contacted the melt level of the molten material, and a melt level contact detection unit. Optical fiber conveying means for advancing the optical fiber a predetermined distance based on the detection of the above, and inserting the tip of the optical fiber into the molten metal surface for temperature measurement of the molten material. Temperature of molten material Measuring device.