Spring pressure-welded type thermometer

Abstract

To provide a spring pressure-welded type thermometer for measuring the temperature of a refractory lining of a furnace, which also enables installation to a narrow part with a limited operation space, and can maintain precision and functions thereof even when a large deformation error compared to design dimensions is generated in a case where, e.g., a deformed furnace bottom steel shell or an instrumented protective tube is diverted.SOLUTION: The outer circumferential side of a sheathed thermocouple 2 is provided with a cylindrical support tube 3 coaxially mounted into a state where the tip side of the sheathed thermocouple 2 is protruded and having a fixation part 30 for being fixed to an opening end part of an instrumented protective tube 8. The sheathed thermocouple 2 is energized movably in an axial direction relative to the support tube 3 and also to the tip side by a spring 4 provided at a rear end part, and a tube region inserted into the instrumented protective tube 8 of the support tube 3 is detachably composed relative to a region of the rear end side.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a spring pressure thermometer for measuring the temperature of a refractory lining of a furnace. [Background technology]

[0002] Spring-pressure thermometers are used as thermometers for measuring the temperature of hearth wall bricks in blast furnaces (see, for example, Patent Document 1). Because the blast furnace shell expands and contracts due to increases and decreases in furnace pressure and increases and decreases in temperature caused by heat transfer from the refractory lining, the insertion distance of the thermometer from the surface of the shell to the hearth wall bricks (refractory lining) also fluctuates. However, by using a spring-pressure thermometer, the tip of the thermocouple sheath, which has the temperature measurement point, can be kept constantly in pressure contact with the hearth wall brick located at the bottom of the temperature measurement hole, regardless of this expansion and contraction, enabling stable temperature measurement.

[0003] The spring pressure-welded thermometer is a thermometer mounted inside an instrumentation protection tube installed in a temperature measurement hole formed in the steel shell of a blast furnace. It comprises a sheathed thermocouple and a support tube fixed to the opening of the instrumentation protection tube, with the tip of the sheathed thermocouple coaxially attached to the outer periphery of the sheathed thermocouple and protruding from the outer periphery. The sheathed thermocouple is axially movable and biased toward the tip by a spring provided at the rear end of the support tube, maintaining the pressure-welded state. Sheathed thermocouples are generally easily bent, but the support tube, which supports the sheathed thermocouple movably while biased toward the tip in the axial direction, has a tube structure with sufficient rigidity to prevent it from bending easily.

[0004] Furthermore, the support tube of such a spring-pressure-contact thermometer requires a relatively large-diameter, predetermined-length region that protrudes outside the shell and houses the spring, in addition to a relatively small-diameter front region that is inserted inside the shell together with the thermocouple sheath. For this reason, with conventional spring-pressure-contact thermometers, the support tube sometimes becomes an obstacle, making installation impossible, particularly in narrow areas of the blast furnace hearth (for example, areas where only about 500 to 600 mm of space can be secured from the outer surface of the shell), even though a universal drill can be used to drill a temperature-measuring opening hole in the stamping material or brick.

[0005] Furthermore, when a spring-pressed thermometer with a travel range of, for example, 25 mm is set on the hearth shell, the tip of the thermocouple sheath is fixed to the shell in a pressed state by about 10 mm. In other words, it is attached in a state that can follow expansion of about 10 mm and contraction of about 15 mm when the blast furnace is operating.

[0006] However, in recent years, in order to reduce costs during blast furnace renovations, it has become common to reuse deformed hearth shells and instrumentation protection tubes attached to the shells, resulting in large deformation errors compared to the design dimensions, and in some cases the sheath tip floats within a range of movement of around 25 mm, making it impossible to maintain functionality and accuracy.In order to increase the range of movement of the sheath tip of a spring-pressed thermometer, it is necessary to increase the length of the spring, i.e. the length of the protruding area of ​​the support tube outside the shell, which further increases the overall length of the thermometer and places a limit on that length. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 4194895 Summary of the Invention [Problem to be solved by the invention]

[0008] In view of the above, the present invention aims to provide a spring-pressure-welded thermometer for measuring the temperature of the refractory lining of a furnace, which can be installed in a narrow area where working space is limited, and which can maintain accuracy and functionality even when a deformation error greater than the design dimensions occurs, for example, when a deformed hearth shell or instrumentation protection tube is reused. [Means for solving the problem]

[0009] In light of this current situation, the inventors conducted extensive research and discovered that, since a spring-pressed thermometer is attached to the inside of a temperature measurement hole (or an instrumentation protection tube attached to said hole), the support tube that biases the sheath thermometer toward the tip and supports it movably can be separated into multiple pieces and made detachable from one another; by connecting and inserting the separated support tubes one after another, it becomes possible to install the thermometer in narrow spaces where installation was previously impossible, and this led to the completion of the present invention.

[0010] That is, the present invention includes the following inventions. (1) A thermometer consisting of a sheathed thermocouple attached inside an instrumentation protection tube inserted into a temperature-measuring hole leading to the refractory lining of a furnace, for measuring the temperature of the refractory lining, wherein a cylindrical support tube is provided on the outer periphery of the sheathed thermocouple, with the tip of the sheathed thermocouple protruding coaxially, and has a fixing part for fixing to the open end of the instrumentation protection tube, and the sheathed thermocouple is movable axially relative to the support tube and biased toward the tip by a spring provided at the rear end, and at least a part of the tube region of the support tube inserted inside the instrumentation protection tube is configured to be detachable from the region on the rear end side.

[0011] (2) The spring pressure type thermometer according to (1), wherein the detachable tube region of the support tube is further divided into two or more detachable tubes.

[0012] (3) A spring pressure-contact type thermometer according to (1) or (2), wherein the fixing portion is fixed to a mounting flange provided on the instrumentation protection tube side and is composed of a mounting flange having a compression fitting structure that can be crimped and fixed at any position within a predetermined axial range on the outer peripheral surface of the rear end region of the support tube. [Effects of the Invention]

[0013] According to the spring pressure type thermometer of the present invention, the support tube is configured so that at least a portion of the tube section inserted into the instrumentation protective tube can be attached and detached from the rear end section. Therefore, even when installing in a narrow area with a limited working space of approximately 500 to 600 mm, by first inserting only the tube section into the instrumentation protective tube and then joining the rear end section to the terminal section, it is often possible to install reliably and accurately.

[0014] Furthermore, this reduction in the problem of working space means that the length of the protruding region of the support tube outside the iron shell can be made longer than before.

[0015] Therefore, by lengthening the spring and increasing the range of movement of the sheath tip, it is possible to design it so that functionality and precision can be maintained even in situations where a large deformation error occurs, for example, due to the reuse of a deformed hearth shell or an instrumentation protection tube attached to the shell.In other words, the problem of working space is solved, and the degree of freedom in design is significantly improved, such as by increasing the length of the spring.

[0016] Furthermore, if the detachable pipe section of the support pipe is further divided into two or more detachable pipes, it is possible to insert a support pipe with a longer overall length into a deeper temperature measurement hole by sequentially joining the two or more divided pipes in the same narrow section.

[0017] Furthermore, if the fixing portion is fixed to a mounting flange provided on the instrumentation protection tube side and is composed of a mounting flange having a compression fitting structure that can be crimped and fixed at any position within a predetermined axial range on the outer peripheral surface of the rear end region of the support tube, then even in situations where the above-mentioned deformed hearth shell or the instrumentation protection tube attached to the shell is reused and a larger deformation error occurs, the crimp-fixing position of the mounting flange, i.e., the insertion length of the support tube into the instrumentation protection tube, can be adjusted, which absorbs the deformation error and enables reliable installation with high precision, making it easy to maintain the pressure-welding function and precision of the set spring. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is an explanatory diagram showing a state in which a spring-pressure-type thermometer according to a representative embodiment of the present invention is installed in a blast furnace. [Figure 2] FIG. 10 is an explanatory diagram showing the same spring-pressed thermometer. [Figure 3] FIG. 10 is an explanatory diagram showing the same spring-pressed thermometer. [Figure 4] FIG. 10 is a longitudinal cross-sectional view of the same spring-pressed thermometer. [Figure 5A] This is an explanatory diagram showing the procedure for installing a spring-pressed thermometer in a blast furnace. [Figure 5B] This is an explanatory diagram showing the procedure for installing a spring-pressed thermometer in a blast furnace. [Figure 5C] This is an explanatory diagram showing the procedure for installing a spring-pressed thermometer in a blast furnace. [Figure 5D] This is an explanatory diagram showing the procedure for installing a spring-pressed thermometer in a blast furnace. [Figure 6] FIG. 10 is an explanatory diagram showing an example of a drill bit for drilling a processing hole. [Figure 7A] 10A to 10C are explanatory diagrams showing an example of a procedure for drilling a processing hole. [Figure 7B] 10A to 10C are explanatory diagrams showing an example of a procedure for drilling a processing hole. [Figure 7C] 10A to 10C are explanatory diagrams showing an example of a procedure for drilling a processing hole. [Figure 8] FIG. 10 is an explanatory diagram showing a spring-pressure type thermometer according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] Next, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0020] As shown in Fig. 1, the spring pressure contact type thermometer 1 of the present invention is a thermometer that is attached inside an instrumentation protection tube 8 that is inserted into a temperature measurement hole 90 that leads to a furnace refractory lining 9, and measures the temperature of the refractory lining 9. As also shown in Figs. 2 to 4, the spring pressure contact type thermometer 1 includes a sheathed thermocouple 2 and a cylindrical support tube 3 that is coaxially attached to the outer periphery of the sheathed thermocouple 2 with the tip of the sheathed thermocouple 2 protruding, and that has an attachment flange 34 for fixing to an attachment flange 82 at the open end of the instrumentation protection tube 8, and the sheathed thermocouple 2 is movable axially relative to the support tube 3 and is biased toward the tip by a spring 4 provided at the rear end.

[0021] In this embodiment, the lining refractory 9 is a blast furnace hearth wall brick 91, but the lining refractory 9 to be measured by the present invention is not limited to such blast furnace hearth wall brick 91. The present invention is also suitable for measuring the temperature of lining refractories in high-temperature melting furnaces, such as cupolas, electric furnaces, and arc furnaces, which have a structure in which the outer periphery is surrounded by a steel shell and the inside is laid with hearth wall bricks or the like, and is widely applicable to materials other than bricks. The temperature measurement hole 90 is composed of an inner peripheral surface 90A of an instrumentation guide pipe 96 that is embedded in advance from the surface of the blast furnace steel shell to the area of ​​the steel shell 92, castable refractories 93, and staves 94, and a machined hole 90B that extends to the tip side of the pipe inner peripheral surface 90A, penetrates a stamped material 95, and reaches the inside of the hearth wall brick 91.

[0022] The instrumentation guide pipe 96 has a pipe structure made of heat-resistant steel such as carbon steel pipe for pressure piping or stainless steel, and specifically, as shown in Fig. 1, it is embedded in the region extending from the steel shell 92, castable 93, and stave 94, and has a sealing metal fitting 81 at its base end that is welded to the outer surface of the steel shell 92. The drilled hole 90B can be formed by inserting the instrumentation protection pipe 8 into the instrumentation guide pipe 96, and then inserting it into the instrumentation protection pipe 8 using a drill bit T1 or adapter with a universal joint 97 as shown in Fig. 6, following the steps shown in Figs. 7A to 7C, and then drilling the stamp material 95 at the end of the instrumentation guide pipe 96 and the hearth wall bricks 91 with a drill driver T2. The instrumentation protection pipe 8 has a pipe structure similarly made of heat-resistant steel such as carbon steel pipe for pressure piping or stainless steel, and is inserted into the region from the base-end opening 8a of the instrumentation guide pipe 96 to the steel shell 92, castable 93, and stave 94, and has an attachment flange 82 at the base-end end that protrudes a predetermined distance outside from the base-end opening 8a of the instrumentation guide pipe 96.

[0023] In this embodiment, both the instrumentation guide pipe 96 and the instrumentation protection pipe 8 are provided in the region up to the staple 94, but they may extend further. In particular, the instrumentation protection pipe 8 may be extended into the hearth wall bricks 91. The mounting flange 82 is provided with bolt insertion holes 82a for mounting the mounting flange 34 of the support pipe 3 described later with bolts and nuts 36.

[0024] The sheathed thermocouple 2 is generally easily bendable, but the thermocouple sheath used to measure the temperature of hearth wall bricks, as in this embodiment, has an outer diameter of 3 mm to 8 mmφ, more specifically, an outer diameter of approximately 3.2 mm to 6.4 mmφ, and is flexible.

[0025] The support tube 3 comprises a tip region R301 made up of a plurality of (two in this example) straight tubes 31A, 31B, a middle region R302 made up of a straight tube 32 having an outer circumferential surface of a predetermined axial length to which a mounting flange 34 serving as a fixing portion 30 fixed to the mounting flange 82 of the instrumentation protection tube 8 is fixed at any position within a predetermined axial range, and a base region R303 made up of a relatively large-diameter straight tube 33 that accommodates a terminal portion 5 connected via an end plate 20 to the base end of a sheathed thermocouple 2 (described later) and a coil spring 4 wrapped around the terminal portion 5 and biasing the terminal portion 5 and the sheathed thermocouple 2 toward the front end. The mounting flange 34 is provided with a bolt insertion hole 34a for the bolt nut 36.

[0026] The front region R301, which is composed of the straight tubes 31A and 31B, is a tube region inserted inside the instrumentation protective tube 8 and is configured to be detachable from the intermediate region R302, which is composed of the straight tube 32 on the rear end side. Specifically, the rear end of the straight tube 31B and the front end of the straight tube 32 are provided with a female thread portion 31d and a male thread portion 32a that thread together, and the two tubes are detachably threaded together by coaxially butting their ends together and rotating them relative to each other. This detachable structure is not limited to the threaded structure shown in this example, and various known mechanical detachable structures can be used.

[0027] In this way, the front end region R301 (straight tubes 31A, 31B), which is the tube region inserted into the instrumentation protective tube 8, is configured to be detachable from the intermediate region R302 on the rear end side. This allows the thermometer to be installed in a narrow area where the working space is limited and a universal drill can be used to drill holes (machined holes) in stamped materials and bricks, but where a conventional spring pressure contact type thermometer could not be installed. As shown in FIGS. 5A to 5D, First, only the sheathed thermocouple 2 (tubes 31A, 31B) is inserted into the instrumentation protection tube 8, and then the bent sheathed thermocouple 2 is inserted into the tip region R301, while the rear end (the rear end portion integrally formed with the intermediate region R302, base region R303, elbow 60, nipple 61, terminal block 62, etc.) is joined to the terminal portion of the tip region R301. This enables reliable and precise installation even in narrow areas where the working space is limited to about 500 to 600 mm, and is expected to expand sales channels.

[0028] Here, the sheathed thermocouple 2 is generally flexible and can usually be bent in advance to a bending radius R of about 200 to 250 mm, depending on the outer diameter. By bending the sheathed thermocouple 2 in this way, it can be inserted into the tip region R301 even in a narrow section, and by bending it back approximately every 30 mm, it can be inserted in a nearly straight line.

[0029] Furthermore, since the front end region R301 (straight tubes 31A, 31B) is detachably configured with respect to the intermediate region R302 on the rear end side, the problem of limited working space is reduced, which means that the length of the protruding region outside the shell can be increased. That is, it is possible to lengthen the straight tube 33 incorporating the coil spring 4, thereby lengthening the spring 4 and increasing the stroke, or to provide the intermediate region R302 and provide a straight tube 32 of a predetermined length for adjusting the position of the mounting flange 34.

[0030] Furthermore, in this example, the detachable pipe region (tip side region R301) is divided into two or more detachable pipes (straight pipes 31A, 31B). As can be seen from Figure 5A, in the same narrow section, first insert only the front straight pipe 31A into the instrumentation protective pipe 8, then connect the rear straight pipe 31B to its rear end to form a single unit, and then insert it into the instrumentation protective pipe 8. In other words, by sequentially joining two or more divided pipes in this way, it becomes possible to insert a support pipe with a longer overall length into a deeper temperature measurement hole.

[0031] In addition, it is also preferable that the detachable tube region (tip region R301) be constructed of a flexible tube rather than a straight tube (31A, 31B, 31) as in this example. This allows installation in narrower, more constricted areas by bending the tube without increasing the number of tubes constituting the tip region R301. Examples of such flexible tubes include metal corrugated tubes with alternating peaks and valleys, such as a one-pitch bellows-shaped corrugated tube. However, various types of flexible tubes, such as spiral tubes and blade-shaped tubes such as wire braids and ribbon braids, can also be used. Using a corrugated tube reduces contact with the sheathed thermocouple inside, reducing the resistance to movement of the sheathed thermocouple and maintaining a stable, constant contact state of the tip of the sheathed thermocouple.

[0032] The detachable structure between the straight tubes 31A and 31B is similar to the structure between the straight tubes 31B and 32 described above, in that the rear end of the straight tube 31A and the front end of the straight tube 31B are provided with a female thread 31b and a male thread 32c that screw together, and the two tubes are detachably screwed together by coaxially butting their ends together and rotating relative to each other. As with the above, this detachable structure is not limited to the screw-type structure of this example, and various known mechanical detachable structures can be used.

[0033] Furthermore, the detachable tube region (tip side region R301) may be configured from only one straight tube 31, as shown in Figure 8. Even if only one tube is used, the single straight tube 31 can be inserted into the instrumentation protective tube 8 first, and then the remaining portion on the rear end can be attached and inserted in the same manner, thereby enabling installation in narrow spaces where conventional spring pressure-displacement thermometers could not be installed. Furthermore, by increasing the number of straight tubes 31 that make up the detachable tube region (tip side region R301) to three or more, installation in even narrower spaces becomes possible.

[0034] The mounting flange 34 has a compression fitting structure 35 that can be crimped and fixed at any position on the outer circumferential surface of the straight pipe 32 of the support pipe 3. Specifically, as shown in Fig. 4, the compression fitting structure 35 is composed of a cylindrical main body 350 that is fixed to the inner circumferential surface of the mounting flange 34 by screwing or welding, a cylindrical cotter 351 that has an inclined surface 351a on its outer periphery that abuts against a tapered surface 350a formed on the inner circumferential surface of the cylindrical main body 350, and a clamping screw 352 that is threaded onto the end of the cylindrical main body 350 and presses the cotter 351 against the tapered surface to crimp it to the outer circumferential surface of the straight pipe 32.

[0035] In this way, by providing the mounting flange 34 with a compression fitting structure 35 that can be crimped and fixed at any position within a predetermined axial range of the outer surface of the support tube 3 (on the outer surface of the straight tube 32), it is possible to reuse the deformed hearth shell or the instrumentation protection tube attached to the shell, and even in situations where larger deformation errors occur, the crimp-fixing position of the mounting flange 34 on the straight tube 32, i.e., the insertion length of the support tube into the instrumentation protection tube, can be adjusted, thereby absorbing deformation errors and maintaining functionality and precision.

[0036] For example, if the deformation error is large, say ±50 mm, a conventional spring pressure-type thermometer, which is installed within an error range of about ±5 mm taking into account the stroke of the sheathed thermocouple by the spring, would not be able to function properly, as the sheathed thermocouple would no longer be press-fitted. However, in the present invention, if the pressure-fixed position of the mounting flange 34 can be adjusted by 100 mm in the axial direction (lengthwise), it becomes possible to install the thermometer in a state where the pressed state of the sheathed thermocouple 2 is reliably maintained with high precision.

[0037] The support pipe 3 (straight pipes 31A, 31B, 32), the mounting flange 34, and the compression fitting structure 35 are made of heat-resistant steel such as stainless steel.

[0038] The straight tube 33 in the base end region R303 has a stepped portion 33c formed on the inner surface of the tip end, the diameter of which is expanded over a predetermined length, and a coil spring 4 having an inner diameter large enough to insert the terminal portion 5 is inserted into this stepped portion 33c from one end side, and abuts against a step portion 33d at the end portion of the stepped portion 33c, while the other end side of the coil spring 4 abuts against the end plate 20, urging the sheathed thermocouple 2 and the terminal portion 5 toward the tip side.

[0039] A terminal section 5 is provided via an end plate 20 provided at the base of the sheathed thermocouple 2 to derive an output signal from the sheathed thermocouple 2. An elastic connection cable (not shown) is provided further to the base end side of the terminal section 5. The elastic connection cable is wired through an elbow 60 and a nipple 61 connected to the base end side of the straight pipe 33 (support pipe 3), and is connected to a terminal section inside a terminal block 62 connected to the tip of the nipple 61.

[0040] The tip 2a of the sheathed thermocouple 2 is always pressed against the bottom 91b of the hole in the hearth wall brick at the back of the temperature measurement hole 90 (machined hole 90B) by the biasing force of the coil spring provided at the rear end of the sheath, making it possible to measure temperature with high accuracy.

[0041] While the embodiments of the present invention have been described above, the present invention is not limited to these examples and can be embodied in various forms without departing from the spirit of the present invention. For example, although a flange connection has been described as an example of the fixing portion in the above examples, a sleeve connection that can be connected to a compression fitting is also possible. [Explanation of symbols]

[0042] 1 Spring pressure thermometer 2 sheathed thermocouples 20 End plate 3 Support tube 30 Fixed part 31A, 31B, 31 Straight pipe 31b, 31d female thread 31c Male thread 32 Straight pipe 32a male thread 33 Straight pipe 33c Stepped section 33d Step 34 Mounting flange 34a Insertion hole 35 compression fitting structure 350 Cylindrical body 350a tapered surface 351 Cotter 351a Slope 352 Fastening screw 36 Bolts and nuts 4 coil springs 5 Terminal section 60 Elbow 61 Nipple 62 Terminal block 8 Instrumentation protection tube 8a aperture 81 Sealing hardware 82 Mating flange 82a Insertion hole 9 Refractory lining 90 Temperature measurement hole 90A pipe inner surface 90B machined hole 91 Hearth Wall Bricks 92 Ironhide 93 Castable 94 Stave 95 Stamp material 96 Instrumentation guide tube 97 Universal Joint R301~R303 area T1 drill bit T2 Drill Driver

Claims

1. A thermometer comprising a sheathed thermocouple attached to an instrumentation protection tube inserted into a temperature measurement hole leading to a refractory lining of a furnace, the thermometer measuring the temperature of the refractory lining, a cylindrical support tube is provided on the outer circumferential side of the sheathed thermocouple, the support tube being coaxially attached to the outer circumferential side of the sheathed thermocouple with a tip end of the sheathed thermocouple protruding therefrom, and the support tube has a fixing portion for fixing the support tube to an open end of the instrumentation protection tube; the sheathed thermocouple is axially movable relative to the support tube and biased toward the tip end by a spring provided at the rear end, At least a part of the pipe region of the support pipe that is inserted into the instrumentation protection pipe is configured to be detachable from the rear end region. Spring pressure thermometer.

2. 2. The spring pressure thermometer according to claim 1, wherein the detachable tube region of the support tube is further divided into two or more detachable tubes.

3. 3. The spring pressure type thermometer according to claim 1, wherein the fixing portion is fixed to a mounting flange provided on the instrumentation protection tube side and is configured as a mounting flange having a compression fitting structure that can be crimped and fixed at any position within a predetermined range in the axial direction on the outer peripheral surface of the rear end region of the support tube.

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