Spring pressure contact thermometer

Abstract

To provide a spring press-contact type thermometer for measuring a temperature of furnace lining refractory, which can be installed in a narrow part with limited work space and can maintain accuracy and functionality even in a case where a significant deformation error occurs compared to design dimensions such as a case where an outer lining steel shell of a furnace bottom is deformed or an installation protective tube is diverted.SOLUTION: A spring press-contact type thermometer is provided with a cylindrical support tube 3 that is mounted coaxially on the outer peripheral side of a sheath thermocouple 2 in a state where the end part side of the sheath thermocouple 2 projects and includes a fixation section 30 for fixing the support tube to the opening end part of an installation protective tube 8. The sheath thermocouple 2 is urged in a movable manner in an axial direction with respect to the support tube 3 and to the end part side by a spring 4 disposed in a rear end part. A region where the support tube 3 is inserted into the installation protective tube 8 is configured of a flexible tube 31.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] As a thermometer for measuring the temperature of the hearth wall bricks of a blast furnace, a spring pressure contact type thermometer is used (see, for example, Patent Document 1). Since the blast furnace steel shell expands / contracts due to the rise / fall of the furnace internal pressure and the rise / fall of the temperature due to heat transfer from the refractory lining, the thermometer insertion distance from the steel shell surface to the hearth wall bricks (refractory lining) also varies. By using a spring pressure contact type thermometer, the tip of the thermocouple sheath with a temperature measurement point can always be maintained in a state of being pressed against the hearth wall bricks located at the bottom of the temperature measurement hole regardless of these expansions / contractions, enabling stable temperature measurement.

[0003] The spring pressure contact type thermometer is a thermometer installed in an instrument protection tube provided in a temperature measurement hole formed in the blast furnace steel shell. It is composed of a sheath thermocouple and a support tube coaxially mounted on the outer peripheral side thereof with the tip side of the sheath thermocouple protruding, and fixed to the opening of the instrument protection tube. The sheath thermocouple is axially movable and biased toward the tip side by a spring provided at the rear end of the support tube to maintain the above-mentioned pressed state. The sheath thermocouple is generally easy to bend, but the support tube that movably supports it in a state of being axially biased toward the tip side has a tube structure with rigidity that does not easily bend for this purpose.

[0004] Furthermore, the support tube of such a spring-pressure type thermometer requires a relatively large diameter and a predetermined length of area that protrudes from the outside of the steel shell and houses the spring, in addition to the relatively small diameter front area that is inserted inside the steel shell together with the thermocouple sheath. For this reason, with conventional spring-pressure type thermometers, installation in narrow areas, especially at the bottom of a blast furnace (for example, in places where only about 500-600 mm of space can be secured from the outside of the steel shell), was sometimes impossible because of the support tube, even though it was possible to drill openings for temperature measurement in the stamp material and bricks using a universal type drill.

[0005] Furthermore, when setting a spring-type thermometer with a travel range of 25 mm, for example, on the furnace bottom shell, the tip of the thermocouple sheath is fixed to the shell by about 10 mm in a pressed position. In other words, it is installed in a way that allows it to accommodate expansion of approximately 10 mm and contraction of approximately 15 mm during blast furnace operation.

[0006] However, in recent years, in order to reduce costs during blast furnace renovations, deformed furnace bottom casings and instrumentation protection tubes attached to the casings are often reused, resulting in large deformation errors compared to the design dimensions. In cases where the sheath tip floats within a movable range of about 25 mm, it becomes impossible to maintain function and accuracy. To increase the movable range of the sheath tip of a spring-pressure type thermometer, it is necessary to increase the length of the spring, that is, the length of the protruding area on the outside of the casing of the support tube, which further increases the overall length of the thermometer, and there is a limit to how long this can be. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Patent No. 4194895 [Overview of the project] [Problems that the invention aims to solve]

[0008] Therefore, in view of the above circumstances, the present invention aims to provide a spring-pressure type thermometer for measuring the temperature of the refractory lining of a furnace, which can be installed in confined spaces where working space is limited, and which can maintain accuracy and functionality even when large deformation errors occur compared to the design dimensions, such as when reusing a deformed furnace bottom iron shell or instrumentation protection tube. [Means for solving the problem]

[0009] In view of the current situation, the inventors have conducted thorough studies and have found that, since the spring-pressure type thermometer is installed inside the temperature-measuring hole (or the instrumentation protection tube attached to the hole), at least the portion of the support tube that biases the sheath thermometer toward the tip and supports it so that it can move, even if the tube structure is easily bendable, its bending is restricted by contact with the inner wall of the temperature-measuring hole or instrumentation protection tube, so as not to hinder the smooth movement of the sheath thermometer. Furthermore, by making the support tube such a portion bendable, it becomes possible to install it even in narrow places where conventional installations were not possible, by bending the portion in question. Based on these findings, the inventors have completed the present invention.

[0010] In other words, the present invention encompasses the following inventions. (1) A thermometer comprising a sheathed thermocouple, which is installed inside an instrumentation protection tube inserted into a temperature-measuring hole leading to the refractory lining of a furnace, and which measures the temperature of the refractory lining, wherein a cylindrical support tube is provided on the outer circumference of the sheathed thermocouple, which is mounted coaxially with the tip of the sheathed thermocouple protruding, and which has a fixing portion for fixing to the open end of the instrumentation protection tube, the sheathed thermocouple is biased toward the tip and is axially movable relative to the support tube by a spring provided at its rear end, and at least a portion of the area of ​​the support tube that is inserted inside the instrumentation protection tube is made of a flexible tube, a spring-pressure type thermometer.

[0011] (2) The spring pressure contact thermometer according to (1), wherein the flexible tube is a corrugated metal tube.

[0012] (3) The spring pressure contact thermometer according to (1) or (2), wherein the fixing portion is fixed to a mounting flange provided on the instrumentation protection tube side and consists 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 surface of the support tube. [Effects of the Invention]

[0013] According to the spring pressure-contact type thermometer of the present invention, since at least a portion of the support tube that is inserted into the instrumentation protection tube is made of a flexible tube, even when installing in a narrow space where the working space is limited to about 500 to 600 mm, the support tube and the thermocouple inside can be bent and easily inserted into the instrumentation protection tube, and in many cases installations can be made reliably and accurately.

[0014] Furthermore, this reduction in workspace limitations means that it becomes possible to increase the length of the protruding area on the outside of the support pipe's metal shell compared to conventional designs.

[0015] Therefore, by increasing the length of the spring and setting a larger range of motion at the tip of the sheath, it becomes possible to design the device to maintain function and accuracy even in situations where large deformation errors occur, such as when reusing a deformed furnace bottom iron shell or an instrumentation protection tube attached to the iron shell. In other words, since the problem of working space is eliminated, the degree of design freedom is greatly increased, such as by increasing the length of the spring.

[0016] Furthermore, if the flexible tube is a corrugated tube, when inserting the support tube into the instrumentation protection tube while bending it together with the thermocouple, even if the instrumentation protection tube comes into contact with the outer surface or the thermocouple comes into contact with the inner surface, the corrugated shape reduces the contact area, i.e., the resistance due to contact, allowing them to slide smoothly against each other, thus preventing damage and maintaining good workability.

[0017] In addition, when the fixing part is composed of a mounting flange that is fixed to the mounting coupling flange provided on the side of the instrumentation protection pipe and has a compression fitting structure that can be pressure-fixed at an arbitrary position within a predetermined axial range on the outer peripheral surface of the support pipe, even in a situation where the above-described deformed furnace bottom iron sheet or the instrumentation protection pipe attached to the iron sheet is diverted and a larger deformation error has occurred, the pressure-fixing position of the mounting flange, that is, the insertion length of the support pipe into the instrumentation protection pipe, can be adjusted. As a result, the deformation error can be absorbed and reliable and highly accurate installation becomes possible, making it easy to maintain the pressure contact function and accuracy of the set spring.

Brief Description of the Drawings

[0018] [Figure 1] An explanatory drawing showing the installation state of the spring pressure-contact type thermometer according to a representative embodiment of the present invention in a blast furnace. [Figure 2] An explanatory drawing showing the spring pressure-contact type thermometer as well. [Figure 3] A longitudinal sectional view showing the spring pressure-contact type thermometer as well. [Figure 4] An explanatory drawing showing the state of installing the spring pressure-contact type thermometer in a blast furnace as well. [Figure 5] An explanatory drawing of the main part showing the installation state of the spring pressure-contact type thermometer as well. [Figure 6] An explanatory drawing showing an example of a drill bit for drilling a processing hole. [Figure 7A] An explanatory drawing showing an example of the procedure for drilling a processing hole. [Figure 7B] An explanatory drawing showing an example of the procedure for drilling a processing hole. [Figure 7C] An explanatory drawing showing an example of the procedure for drilling a processing hole. [Figure 8] An explanatory drawing showing a modification example of the spring pressure-contact type thermometer as well. [Figure 9] An explanatory drawing showing the state of installing the modified spring pressure-contact type thermometer in a blast furnace. [Figure 10] An explanatory drawing showing another modification example of the spring pressure-contact type thermometer as well. [Figure 11] An explanatory diagram showing how the modified spring-type thermometer is installed in a blast furnace. [Figure 12] This diagram illustrates yet another variation of the spring-type thermometer. [Figure 13] An explanatory diagram showing how the modified spring-type thermometer is installed in a blast furnace. [Modes for carrying out the invention]

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

[0020] As shown in Figure 1, the spring-pressure type thermometer 1 of the present invention is installed inside an instrumentation protection tube 8 inserted into a temperature-measuring hole 90 leading to the refractory lining 9 of a furnace, and measures the temperature of the refractory lining 9. As also shown in Figures 2 and 3, the spring-pressure type thermometer 1 comprises a sheathed thermocouple 2 and a cylindrical support tube 3 that is coaxially mounted on the outer circumference of the sheathed thermocouple 2 with the tip of the sheathed thermocouple 2 protruding, and has a mounting flange 34 for fixing to a mounting flange 82 for the open end of the instrumentation protection tube 8. The sheathed thermocouple 2 is biased toward the tip and is axially movable relative to the support tube 3 by a spring 4 provided at its rear end.

[0021] In this embodiment, an example is shown where the refractory lining 9 is the hearth wall brick 91 of a blast furnace. However, the refractory lining 9, which is the target of temperature measurement in the present invention, is not limited to the hearth wall brick 91 of a blast furnace. It is also suitable for temperature measurement of refractory linings in high-temperature melting furnaces other than blast furnaces, such as cupolas, electric furnaces, and arc furnaces, where the outer perimeter is surrounded by an iron shell and the inside is brick-laid with hearth wall bricks, and can be broadly applied to members other than bricks. The temperature-measuring hole 90 consists of the inner circumferential surface 90A of the instrumentation guide tube 96, which is pre-embedded in the area from the surface of the blast furnace iron shell to the iron shell 92, castable 93, and staves 94, and a processed hole 90B that extends to the tip side and is drilled with a drill or the like, passing through the stamp material 95 and reaching 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. Specifically, as shown in Figure 1, it has a sealing fitting 81 at its base end that is embedded in the area leading to the steel shell 92, castable 93 and staves 94 and welded to the outer surface of the steel shell 92. The processed hole 90B can be formed by inserting the instrumentation protection pipe 8 into the instrumentation guide pipe 96, and then using a drill bit T1 with a universal joint 97 or an adapter as shown in Figure 6, inserting it into the instrumentation protection pipe 8 in the procedure shown in Figures 7A to 7C, and then drilling a hole in the stamp material 95 and hearth wall brick 91 at the end of the instrumentation guide pipe 96 with a drill driver T2. The instrumentation protection tube 8 also has a pipe structure 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 tube 96 to the steel shell 92, castable 93 and staves 94, and has a mounting flange 82 at the base end that protrudes to the outside by a predetermined length from the base end opening 8a of the instrumentation guide tube 96.

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

[0024] While sheathed thermocouples 2 are generally easily bendable, thermocouple sheaths used for measuring the temperature of hearth wall bricks, as in this embodiment, have an outer diameter of 3 mm to 8 mmφ, more specifically, an outer diameter of about 3.2 mm to 6.4 mmφ, and are flexible.

[0025] The support pipe 3 comprises a tip-side region R301 made of a flexible pipe 31, an intermediate region R302 consisting of a straight pipe 32 having an outer surface of a predetermined length in the axial direction, to which a mounting flange 34, which serves as a fixing part 30 fixed to the mounting flange 82 of the instrumentation protection pipe 8, is fixed at any position within a predetermined range in the axial direction, and a base-side region R303 consisting of a relatively large-diameter straight pipe 33 which houses a terminal part 5 connected to the base end of the sheathed thermocouple 2 (described later) via an end plate 20, and a coil-shaped spring 4 that is externally mounted on the terminal part 5 and biases the terminal part 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 flexible tube 31 is a corrugated metal tube with alternating peaks and valleys. In this example, a one-pitch type bellows-shaped corrugated tube is shown, but examples include tubes formed from thin sheet material. In addition to the bellows shape, various types of flexible tubes can be made, such as spiral shapes and blade shapes such as wire braids and ribbon braids. By using a corrugated tube, contact with the sheath thermocouple inside is reduced, which reduces the resistance to the movement of the sheath thermocouple and has the advantage of maintaining a stable constant contact state at the tip of the sheath thermocouple.

[0027] Thus, because the support tube 3 is composed of a flexible tube 3, even in narrow spaces where the workspace is limited and it is possible to drill holes (processed holes) in stamp material and bricks using a universal type drill, but where conventional spring-pressure type thermometers could not be installed, the flexible tube 31 of the support tube 3 and the sheathed thermocouple 2 inside it can be easily inserted into the instrumentation protection tube 8 by bending them, as shown in Figure 4, thus enabling installation and expanding the market. In this case, if the flexible tube 3 is a corrugated tube, even if the instrumentation protection tube comes into contact with the outer surface or the thermocouple comes into contact with the inner surface, the corrugated shape keeps the contact area, i.e., the resistance due to contact, small, allowing them to slide and move smoothly against each other, preventing damage and maintaining good workability.

[0028] Furthermore, the reduction in workspace issues by constructing the structure using flexible pipes 3 in this manner means that it becomes possible to increase the length of the protruding area on the outside of the steel shell. In other words, it becomes possible to lengthen the straight pipe 33 containing the coil spring 4, thereby increasing the stroke of the spring 4, or to provide an intermediate region R302 and a straight pipe 32 of a predetermined length for adjusting the position of the mounting flange 34.

[0029] 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 Figure 3, the compression fitting structure 35 consists of a cylindrical body 350 fixed to the inner circumferential surface of the mounting flange 34 by screwing or welding, a cylindrical cotter 351 having an inclined surface 351a on its outer circumference that contacts a tapered surface 350a formed on the inner circumferential surface of the cylindrical body 350, and a tightening screw 352 that is screwed to the end of the cylindrical body 350 and presses the cotter 351 against the tapered surface to crimp it to the outer circumferential surface of the straight pipe 32.

[0030] By providing a mounting flange 34 having a compression fitting structure 35 that can be crimped and fixed at any position within a predetermined axial range on the outer surface of the support pipe 3 (on the outer surface of the straight pipe 32), even in situations where a deformed furnace bottom iron shell or instrumentation protection tube attached to the iron shell is reused and a larger deformation error occurs, the crimping and fixing position of the mounting flange 34 on the straight pipe 32, i.e., the insertion length of the support pipe into the instrumentation protection tube, can be adjusted, thereby absorbing the deformation error and maintaining function and accuracy.

[0031] For example, if the deformation error is as large as ±50 mm, conventional spring-type thermometers, which were installed within an error range of approximately ±5 mm considering the stroke of the sheathed thermocouple by the spring, would not function properly, such as the sheathed thermocouple failing to make contact, making them incompatible with the situation. However, in the present invention, by making the crimping and fixing position of the mounting flange 34 adjustable by 100 mm in the axial direction (length direction), it becomes possible to install the sheathed thermocouple 2 in a state where the pressing state is maintained with high accuracy and reliability.

[0032] The support pipe 3 (flexible pipe 31, straight pipe 32), mounting flange 34, and compression fitting structure 35 are constructed using, for example, heat-resistant steel such as stainless steel.

[0033] The straight pipe 33 in the base end region R303 has a stepped section 33c formed on the inner surface of the tip, which is widened over a predetermined length. A coil-shaped spring 4, having an inner diameter through which the terminal section 5 can be inserted, is inserted from one end into this stepped section 33c, and contacts the stepped section 33d at the end of the stepped section 33c, while the other end of the coil-shaped spring 4 contacts the end plate 20, biasing the sheathed thermocouple 2 and the terminal section 5 toward the tip.

[0034] A terminal section 5 is provided to derive the output signal from the sheathed thermocouple 2 via an end plate 20 located at the base of the sheathed thermocouple 2. Further towards the base end of the terminal section 5, an expandable connecting cable (not shown) is provided. The expandable connecting cable is wired inside the elbow 60 and nipple 61 connected to the base end of the straight pipe 33 (support pipe 3), and is connected to a terminal section inside the terminal block 62 connected to the end of the nipple 61.

[0035] Figure 5 is an explanatory diagram showing the flexible tube 31 and the sheathed thermocouple 2 protruding from its tip in the tip-side region of the support tube 3 of the spring-compression type thermometer 1 when it is inserted into the instrumentation protection tube 8. The tip portion 2a of the sheathed thermocouple 2 is constantly pressed against the bottom portion 91b of the hole in the furnace bottom wall brick at the back of the temperature-measuring hole 90 (processed hole 90B) by the biasing force of the coil-shaped spring provided at the rear end of the sheath, enabling accurate temperature measurement.

[0036] Furthermore, the bending of the support tube 3 is restricted by the temperature sensing hole 90 (machined hole 90B) and the inner wall of the instrumentation protection tube 8, maintaining a shape that does not hinder the axial movement of the sheathed thermocouple 2. This bending of the support tube 3 also has the effect of absorbing the deformation errors mentioned above to some extent.

[0037] Although embodiments of the present invention have been described above, the present invention is not limited in any way to these embodiments, and can be implemented in various forms without departing from the spirit of the invention. For example, in the above example, a flange connection was described as the fixing part, but other connections, such as a sleeve connection that can be connected to a compression fitting, are also possible.

[0038] Furthermore, in the above embodiment, almost the entire area (tip-side area R301) of the support tube that is inserted into the instrumentation protection tube interior 8 is made of flexible tube 31, but the present invention is not limited to this, and only a part of the said area may be made of flexible tube. For example, as shown in Figure 8, even if the straight tube 32 is extended to the tip-side area R301 and only the tip-side half of that area is made of flexible tube 31, as shown in Figure 9, the tip-side half of the flexible tube 31 and the sheathed thermocouple 2 inside it can be easily inserted into the instrumentation protection tube 8 while bending, making installation possible.

[0039] Another example is to use a flexible pipe 31 for only the base half, as shown in Figure 10, and a straight pipe 32A for the tip half. In this case, as shown in Figure 11, it becomes possible to install the pipe in a narrower, more confined space compared to the example in Figure 8. Furthermore, by applying the example in Figure 10, as shown in Figure 12, even if the tip region R301 is composed of multiple straight pipes 32A, 32B and one or more flexible pipes 31A, 31B connecting them, as shown in Figure 13, the flexible pipes 31A, 32B bend, causing the straight pipes 32A, 32B to bend at an angle to each other, similarly enabling installation in a narrow, confined space. [Explanation of Symbols]

[0040] 1. Spring-type pressure-contact thermometer 2 Sheathed thermocouples 20 End plate 3 support tubes 30 Fixed part 31, 31A, 31B Flexible pipes 32, 32A, 32B straight tubes 33 Straight pipes 33c Stepped machined section 33d Step section 34 Mounting flange 34a Through hole 35 Compression Fitting Structure 350 Cylindrical body 350a Tapered surface 351 Cotter 351a Slope 352 Tightening screws 36 bolts and nuts 4. Coil spring 5 Terminal section 60 Elbow 61 Nipple 62 Terminal block 8. Instrumentation protection tube 8a aperture 81. Seal hardware 82 Connection flange 82a Through hole 9. Fire-resistant lining 90 temperature-sensing holes 90A Inner surface of pipe 90B machined hole 91 Hearth wall bricks 92 Ironhide 93 Castable 94 Steve 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 that can be installed in a narrow space where the outer spatial distance along the length direction of the temperature-sensing hole from the outer surface of the iron shell is smaller than the total length of the thermometer, and is mounted inside an instrumentation protection tube inserted into the temperature-sensing hole leading to the refractory lining of a furnace, for measuring the temperature of the refractory lining, A cylindrical support tube is provided on the outer circumference of the sheathed thermocouple, which is coaxially mounted with the tip of the sheathed thermocouple protruding, and which has a fixing portion for fixing to the open end of the instrumentation protection tube. The sheathed thermocouple is biased toward the tip and is axially movable relative to the support tube by a spring provided at its rear end. At least a portion of the support pipe that is inserted into the instrumentation protection pipe is made of a bendable flexible pipe and is configured to be installed while bending that portion. Spring-type pressure-contact thermometer.

2. The spring pressure contact type thermometer according to claim 1, wherein the flexible tube is a corrugated metal tube.

3. The spring pressure contact thermometer according to claim 1 or 2, wherein the fixing portion is fixed to a mounting flange provided on the instrumentation protection tube side and consists 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 surface of the support tube.

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