JP5625819B2 - Detection method of water seal breakage in furnace - Google Patents

Description

  The present invention relates to a method for early detection of breakage of a water seal in a furnace such as a walking beam type heating furnace or a heat treatment furnace.

  In furnaces such as walking beam heating furnaces and heat treatment furnaces, the material to be heated is supported alternately by a fixed beam and a moving beam, and walking in the furnace is performed by box motion or oval motion consisting of moving the beam up and down and back and forth. Since the opening is provided in the hearth so that the moving beam post supporting the moving beam can be moved up and down and horizontally, the atmosphere gas leaked from the furnace through the hearth opening. A water seal is often used to partition the outside of the furnace (see Patent Document 1).

  In the water seal, a seal plate lowered from the vicinity of the hearth opening is immersed in water in the sealing trough in a bowl-shaped sealing trough arranged below the hearth, and the hearth opening and the sealing trough below the hearth opening. The moving plate of the moving beam post pierced through the opening is immersed in the water in the sealing trough with the seal plate lowered into the sealing trough from the position between the hearth opening and the sealing trough opening. The moving beam post allowed to pass through the seal trough is moved into the seal trough, and the seal trough is moved together by the moving beam post so that the atmosphere gas leaked from the furnace through the hearth opening is sealed with the seal plate. It is enclosed and sealed with water in the seal trough.

JP 59-162218 A

  However, the water seal may corrode or deteriorate due to the atmosphere gas leaked from the furnace or the water in which the atmosphere gas is dissolved, and the seal plate immersed in the water in the seal trough may be damaged. And if the opening due to breakage is large, the part below the hearth is at a negative pressure due to the temperature difference from the inside of the furnace, so air enters the furnace from the broken opening of the seal plate and the furnace temperature rises. It may decrease locally and affect the material to be heated and thus the quality of the product.

  In particular, the seal plate with the water seal lowered from the position between the hearth opening and the seal trough opening of the moving beam post, which is loosely passed through the hearth opening and the seal trough opening below it, is used as the seal trough. In the case of a structure that is immersed in the water inside, the seal plate that is lowered from the moving beam post is surrounded by the outer seal plate that is lowered from the periphery of the hearth opening, and the sealing plate is lowered from the periphery of the hearth opening. Since the seal plate that is lowered from the moving beam post is located on the inside, if the seal plate on the inside is damaged, it cannot be visually confirmed from the outside. There was a problem that it was necessary to remove the plate, and it was a large-scale work after extinguishing the furnace.

  For this reason, as a water seal damage detection method other than direct visual inspection that can be performed without extinguishing the furnace, a smoke test is performed around the outer seal plate with the furnace pressure lowered, and smoke is sucked into the water seal. There is also known a method of checking whether or not. However, in this method, there is generally no sufficient scaffolding or space on the walking beam drive device, so it takes time to prepare for the installation of the scaffolding, etc. and the working environment is poor due to the high ambient temperature during furnace combustion. There was a problem that there were many.

  In order to solve the above-mentioned problems, the present invention can easily and constantly monitor the presence or absence of water seal breakage without extinguishing the furnace and without trouble, and to detect water seal breakage at an early stage. It is an object of the present invention to provide a damage detection method capable of performing the above.

  The water seal breakage detection method of the present invention that achieves the above object is to detect a water seal breakage in a walking beam type furnace in the furnace below the hearth opening of each moving beam post of the walking beam. A temperature sensor is provided at a position exposed to atmospheric gas from the atmosphere, and it is judged that the water seal has broken when the atmospheric temperature detected by this temperature sensor is lower than the normal atmospheric temperature of the seal plate. It is what.

  In a heating furnace, a heat treatment furnace, etc., the atmospheric gas pressure in the vicinity of the heated material in the furnace is usually controlled to around 10 Pa, and the atmospheric gas pressure is reduced to around 0 Pa in the vicinity of the furnace floor where the atmospheric temperature is lower than the heated material vicinity. The atmospheric gas pressure is always negative at the water seal part below the hearth. For this reason, when the seal plate of the water seal is broken, outside air is sucked from the broken portion, and the temperature of the ambient gas near the moving beam post is lowered.

  Thus, according to the water seal breakage detection method of the present invention, the atmospheric temperature is detected by the temperature sensor provided at the position where each moving beam post of the walking beam is exposed to the atmospheric gas from inside the furnace below the hearth opening. If the detected ambient temperature falls below the normal ambient temperature of the seal plate, it is determined that the water seal has been damaged, so monitor the water seal for damage and extinguish the furnace. It can be performed easily and constantly without trouble, and can detect water seal breakage early and reliably, thereby heat treating a large number of products due to local decrease in furnace temperature Non-compliance can be prevented.

Furthermore, in the water seal breakage detection method of the present invention, the water seal is fixedly disposed below the hearth from the position between the hearth opening and the seal trough opening of the moving beam post of the walking beam. The inner seal plate lowered in the seal trough is surrounded by the outer seal plate lowered in the seal trough from the periphery of the hearth opening , and each moving beam post of the walking beam, hearth hand upon than the opening providing a temperature sensor in the exposed position to the ambient gas in the lower, the temperature sensor, the walking beam post, at below the hearth opening, above the said inner sealing plates It is provided in the position .

According to the water seal breakage detection method of the present invention as described above, the inner seal plate of the moving beam post lowered from the position between the hearth opening and the seal trough opening is disposed around the hearth opening. Even if the inner or outer seal plate of the water seal that has a double structure surrounded by the outer seal plate taken down from the inner side is damaged, it can be detected early and reliably. It is possible to prevent heat treatment incompatibility of a large amount of products due to a decrease in furnace temperature.

  In the water seal breakage detection method of the present invention, the temperature sensor preferably includes a thermocouple. In this way, since the thermocouple is inexpensive and has high heat resistance and durability, it is possible to reliably detect damage to the water seal over a long period of time using inexpensive equipment.

It is sectional drawing which shows the water seal of the furnace to which one Example of the failure detection method of the water seal of this invention is applied.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a water seal of a furnace to which one embodiment of the water seal breakage detection method of the present invention is applied. In FIG. 1, reference numeral 1 denotes a hearth of a walking beam type heat treatment furnace. Reference numeral 2 denotes a moving beam located in the furnace at the lowered and retracted positions in the figure.

  The walking beam type heat treatment furnace extends in the left-right direction in FIG. 1, and a plurality of moving beams 2 are lined up in the furnace together with a fixed beam (not shown) fixed in the furnace of the heat treatment furnace. Extends along. The moving beam 2 and the fixed beam alternately support a material to be heated (not shown), and the material to be heated is generated by a box motion consisting of moving the beam 2 up and down and moving back and forth as indicated by a thick arrow in the lower right of the figure. In the furnace, the material to be heated is moved by a predetermined distance from the right to the left in the figure, and the material to be heated is moved from the surroundings by a heating device (not shown) in the atmosphere gas G supplied into the furnace during the stepping movement. It is heated and subjected to a predetermined heat treatment.

  In order to perform a box motion consisting of moving the moving beam 2 up and down and back and forth, a plurality of moving beam posts 3 supporting the moving beam 2 are allowed to pass through the hearth 1 so as to be movable vertically and horizontally, respectively. An opening 1a is provided, and each of the plurality of moving beam posts 3 is erected on the walking beam driving frame 4 and driven by a known driving device (not shown) via the walking beam driving frame 4. It is moved up and down and moved back and forth as indicated by a thick arrow at the lower right of.

  A lid 5 is attached to the moving beam post 3 so as to close each opening 1a of the hearth 1, and the hearth opening 1a is closed by the lid 5 while the moving beam post 3 is lowered. However, since a gap is formed between the hearth 1 and the lid 5 when the moving beam post 3 is raised, the atmospheric gas G leaks out of the furnace through the gap and the hearth opening 1a. Therefore, a water seal is provided below the hearth 1 to partition the atmospheric gas G from the outside of the furnace. Note that the lid 5 may not be installed.

  In the water seal here, the outer seal plate 7 lowered from the periphery of the hearth opening 1a is immersed in the water in the seal trough 6 in a bowl-shaped seal trough 6 fixedly arranged below the hearth. The inner seal plate of the moving beam post 3 loosely passed through the opening 1a and the seal trough opening 6a below the opening 1a is lowered into the seal trough 6 from the position between the hearth opening 1a and the seal trough opening 6a. By immersing 8 in the water in the seal trough 6, the atmosphere gas G leaked from the furnace through the hearth opening 1a is surrounded by the seal plates 7 and 8 and sealed with the water in the seal trough 6. Is.

  In such a water seal, the seal plates 7 and 8 immersed in the water in the seal trough 6 may be damaged or corroded by the atmospheric gas G leaking from the furnace or the water in which the atmospheric gas G is dissolved. In particular, the intermediate portion of the inner seal plate 8 is easily corroded or deteriorated because it is immersed in or lifted from the water in the fixed seal trough 6 as the moving beam post 3 moves up and down. If the opening due to breakage is large, the portion below the hearth 1 is at a negative pressure due to the temperature difference from the inside of the furnace, so that air enters the furnace from the broken openings of the seal plates 7 and 8. There is a possibility that the temperature in the furnace will be locally lowered, and the quality of the heated material and thus the product will be affected. Moreover, the water seal here has a double structure in which the inner seal plate 8 lowered from the moving beam post 3 is surrounded by the outer seal plate 8 lowered from the periphery of the hearth opening 1a. If it is damaged, it cannot be visually confirmed from the outside.

  Therefore, in the water seal breakage detecting method of this embodiment, in order to detect the breakage of the outer and inner seal plates 7 and 8 having the double structure of the water seal in the above-described walking beam type heat treatment furnace, The position of each moving beam post 3 exposed to the atmospheric gas G from the inside of the furnace below the hearth opening 1a, specifically, below the hearth opening 1a of each moving beam post 3, A temperature sensor 9 is provided at a position above the inner seal plate 8. As this temperature sensor 9, what has a thermocouple in a casing, for example can be used.

  In the water seal breakage detection method of this embodiment, the temperature sensor 9 is connected to, for example, a computer (not shown), and the computer uses the temperature sensor 9 during operation of the heat treatment furnace based on a program given in advance. The ambient temperature around the detected temperature sensor 9 and the temperature sensor 9 around the temperature sensor 9 during normal operation of the heat treatment furnace when the seal plates 7 and 8 are detected by the temperature sensor 9 and stored in the computer in advance. The ambient temperature is compared every predetermined time (for example, 1 minute). As a result of the comparison, the ambient ambient temperature detected by the temperature sensor 9 during the operation of the heat treatment furnace is the normal temperature of the seal plates 7 and 8. When the ambient temperature around the sensor 9 is lowered by a predetermined temperature (for example, 30 ° C.) or more, the water seal outer and inner seal plates 7, Any corruption outputs a warning signal it is determined that occurred.

  Therefore, according to the water seal breakage detection method of this embodiment, the temperature provided at the position where each moving beam post 3 of the walking beam is exposed to the atmospheric gas G from the furnace below the hearth opening 1a. When the sensor 9 detects the ambient temperature and the detected ambient temperature falls below the normal ambient temperature of the seal plates 7 and 8, it is determined that the water seal has been damaged. Can be easily and constantly monitored without extinguishing the furnace and taking time, and it is possible to detect the breakage of the water seal early and reliably, thereby reducing the local temperature inside the furnace. It is possible to prevent heat treatment incompatibility of a large amount of products due to the above.

  In addition, according to the water seal breakage detection method of this embodiment, the water seal is lowered into the seal trough 6 from the position between the hearth opening 1a and the seal trough opening 6a of the moving beam post 3. The seal plate 8 has a double structure which is surrounded by an outer seal plate 7 which is lowered from the periphery of the hearth opening 1a into the seal trough 6, and the temperature sensor 9 is connected to the moving beam post 3 from the hearth opening 1a. The lower and lower inner seal plates 8 are provided at positions above the inner seal plate 8, so that any of the outer and inner seal plates 7 and 8 can be detected early and reliably. It is possible to prevent heat treatment incompatibility of a large amount of products due to a decrease in furnace temperature.

  Furthermore, according to the water seal breakage detection method of this embodiment, if the temperature sensor 9 is provided with a thermocouple, the thermocouple is inexpensive and has high heat resistance and durability. It is possible to reliably detect the water seal breakage.

  As mentioned above, although demonstrated based on the Example, this invention is not limited to the above-mentioned example, For example, the walking beam type furnace which can apply the method of this invention is not restricted to a heat treatment furnace, Other types of furnaces for heating and soaking may be used.

  In addition, the water seal to which the method of the present invention can be applied includes immersing a seal plate lowered from the periphery of the hearth opening in a bowl-shaped seal trough disposed below the hearth, The moving beam post loosely penetrated into the opening is made to penetrate the seal trough, and the sealing trough is moved together with the moving beam post so that a single atmosphere gas leaked from the furnace through the hearth opening. In this case, the temperature sensor is positioned below the hearth opening and exposed to the atmospheric gas G from the hearth opening. By providing it at an appropriate position between the portion and the seal trough, the breakage of the seal plate can be detected early and reliably.

  Furthermore, in the present invention, the ambient ambient temperature detected by the temperature sensor is compared with the normal ambient temperature of the seal plate, or the ambient ambient temperature detected by the temperature sensor is more predetermined than the normal ambient temperature of the seal plate. The determination as to whether or not the temperature has dropped or more, and therefore the determination as to whether or not the seal plate of the water seal has broken, may be performed by an electric circuit other than a computer or by a person.

  In the present invention, the temperature sensor is not limited to the one provided with the thermocouple, but may be another type.

  Thus, according to the water seal breakage detection method of the present invention, the atmospheric temperature is adjusted by the temperature sensor provided at the position where each moving beam post of the walking beam is exposed to the atmospheric gas from the furnace below the hearth opening. If the detected ambient temperature drops below the normal ambient temperature of the seal plate, it is determined that the water seal has been damaged. In addition, it can be performed easily and constantly without any hassle, and the failure of the water seal can be detected early and reliably, which makes it incompatible with heat treatment of a large number of products due to local decrease in furnace temperature. Can be prevented.

1 hearth 1a opening 2 moving beam 3 moving beam post 4 walking beam drive frame 5 lid 6 seal trough 6a opening 7 outer seal plate 8 inner seal plate 9 temperature sensor G ambient gas

Claims (2)

The water seal is placed inside the furnace plate with the inner seal plate lowered from the position of the walking beam moving beam post between the hearth opening and the sealing trough opening into the sealing trough which is fixedly positioned below the hearth. In detecting a water seal breakage in a walking beam type furnace having a double structure surrounded by an outer seal plate lowered from the periphery of the floor opening into the seal trough ,
The temperature sensor, of said each mobile beams posts of the walking beam, which is exposed position to an atmosphere gas from the furnace at a lower than the hearth opening than said inner sealing plate below the hearth opening Also set up in the upper position ,
A water seal breakage detection method, wherein the water seal breakage is judged to have occurred when the ambient temperature detected by the temperature sensor is lower than the normal atmosphere temperature of the seal plate. The temperature sensor is characterized in that comprising a thermocouple, breakage detection method of the water seal according to claim 1, wherein.

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