JP5953822B2 - Heating furnace abnormality detection method - Google Patents

Description

  The present invention relates to a method for early detection of abnormalities caused by air intrusion in a walking beam type heating furnace.

  In a conventional heating furnace, an ideal (zero unburned gas, minimal excess air) combustion state is ensured by analyzing components of exhaust gas in the furnace and adjusting the air-fuel ratio.

  There are several methods for improving the soundness of the furnace body of the heating furnace, such as the trend management of the exhaust gas temperature at the bottom of the furnace and the trend management of the fuel intensity, but a method for quantitatively evaluating the effect of intrusion air has not yet been established. Absent. This is because when the steel material to be heated is extracted, the extraction door is opened, and the amount of intrusion air increases at that time. Therefore, there are many disturbances, and it has not yet been possible to detect air intrusion due to equipment abnormality.

  By the way, in a walking beam type heating furnace, a material to be heated is alternately supported by a fixed beam and a moving beam, and is moved stepwise in the furnace by a box motion or an oval motion consisting of raising and lowering and moving the moving beam back and forth. Therefore, since an opening is provided in the hearth to allow the moving beam post supporting the moving beam to move freely up and down and horizontally, the atmosphere gas leaked from the inside of the furnace through the hearth opening and the outside of the furnace In many cases, a water seal is used for partitioning (see Patent Document 1).

  In the water seal, a seal box 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 inner seal box of the moving beam post passed through the opening and lowered into the sealing trough from the position between the hearth opening and the sealing trough opening is immersed in the water in the sealing trough, or the hearth opening By moving the moving beam post that has been allowed to penetrate into the seal trough and moving the seal trough together with the moving beam post, the atmosphere gas leaked from the furnace through the hearth opening is sealed box And sealed with water in the seal trough.

JP 59-162218 A

  In such walking beam type heating furnaces, there are the above-mentioned seal troughs and seal boxes as inlets for intruding air. In order to check the soundness of the equipment, the equipment inspection should be conducted for all the seal troughs and seal boxes. Although it may be carried out, it is not practical because it takes a lot of time because of the large number of cases and it is necessary to extinguish the furnace.

  In order to solve the above-mentioned problems, the present invention can easily monitor the presence or absence of intruding air at all times without extinguishing the furnace and without trouble, and can improve the soundness of the furnace body of the heating furnace. An object of the present invention is to provide a heating furnace abnormality detection method.

  In order to achieve the above object, according to the present invention, at least one of an oxygen concentration meter and a pressure gauge is connected to each seal box, and in particular, the presence or absence of intrusion air due to perforation of equipment is determined.

That is, in the heating furnace abnormality detection method of the present invention, the water seal is a seal in which the walking beam moving beam post is fixedly disposed below the hearth from a position between the hearth opening and the seal trough opening. A walking beam heating furnace having a double structure in which the inner seal box lowered into the trough is surrounded by the outer seal box lowered from the periphery of the hearth opening to the inside of the seal trough. When detecting an abnormality due to the intrusion of air into the furnace, at least one of an oximeter and a pressure gauge is connected to the outer seal box, and the detection result of at least one of the oximeter and the pressure gauge is determined as normal equipment. There is intrusion air due to perforation of equipment when the detection result differs from the normal one by more than a predetermined amount By determining, it is characterized in that to detect an abnormality of the heating furnace.

  Conventionally, it has not been found that there is intrusion air, but according to the present invention, it is possible to determine whether or not there is intrusion air and determine whether or not equipment repair is necessary. Moreover, since the presence or absence of the intruding air can be easily and constantly monitored without extinguishing the furnace and taking time and effort, the soundness of the furnace body of the heating furnace can be achieved reliably at low cost.

In the present invention, at least one of an oximeter and a pressure gauge may be connected to all outer seal boxes that respectively surround all the moving beam posts in the heating furnace. divided, for the moving beam post of at least one in each compartment it may be possible to connect at least one of the oxygen concentration meter and a pressure gauge to the outer seal box surrounding the walking beam post, this way For example, it is possible to grasp the air intrusion location at a lower cost than when connecting at least one of the oximeter and pressure gauge to all outer seal boxes, and it is cheaper to determine the appropriate repair range and prevent the deterioration of the basic unit. Can get to.

In the present invention, the other ends of the plurality of pipes each having one end connected to the plurality of outer seal boxes may be switched and connected to at least one of the oxygen concentration meter and the pressure gauge, Thus, since it is monitored intrusion air oximeter and the number of the outer seal boxes than the number of the pressure gauge, less expensive than the case of providing the oximeter and a pressure gauge for each outer seal box air The intrusion location can be determined, the appropriate repair range can be determined and the basic unit deterioration prevention effect can be obtained inexpensively, and the oxygen concentration meter and pressure gauge can be placed away from the outer seal box, so the oxygen concentration The influence of heat in the furnace on the gauge and pressure gauge can be reduced.

It is sectional drawing which shows the water seal of the heating furnace to which one Example of the heating furnace abnormality detection method of this invention is applied. It is explanatory drawing which shows the example of a failure detection of the water seal by other one Example of the heating furnace abnormality detection method of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view showing a water seal of a heating furnace to which one embodiment of the heating furnace abnormality 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. Is moved up and down and moved back and forth as indicated by a thick arrow at the bottom 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, an outer seal box 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. An inner seal box in which 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 a 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 boxes 7 and 8 and sealed with the water in the seal trough 6. Is.

  In such a water seal, the seal boxes 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. Particularly, the intermediate portion of the inner seal box 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 ideal (zero unburned gas, excessive excess air) combustion state may be impaired and the fuel consumption rate may be deteriorated.

  Moreover, the water seal here has a double structure in which the inner seal box 8 lowered from the moving beam post 3 is surrounded by the outer seal box 7 lowered from the periphery of the hearth opening 1a. If it is damaged, it cannot be visually confirmed from the outside.

  Therefore, in the heating furnace abnormality detection method of this embodiment, in order to detect the intrusion of air due to the breakage of the outer and inner seal boxes 7 and 8 having the double structure of the water seal in the walking beam type heat treatment furnace described above, Detection holes are provided in all the outer seal boxes 7 surrounding all the moving beam posts 3 of the walking beam, and one end of the detection pipe 9 is connected to each hole. The end portion is connected to one or a plurality of normal pressure gauges 11 that are fewer than the outer seal box 7 via, for example, a rotary switching valve 10.

  In the heating furnace abnormality detection method of this embodiment, the pressure gauge 11 is connected to a computer (not shown), for example, and the computer detects the pressure gauge 11 during operation of the heat treatment furnace based on a program given in advance. The pressure of the atmospheric gas G in the outer seal box 7 and the outer seal box 7 during the operation of the heat treatment furnace when the seal box 7 and 8 detected in advance by the pressure gauge 11 and stored in the computer are normal. The pressure of the atmospheric gas G inside is compared every predetermined time (for example, 60 minutes) while sequentially switching the outer seal box 7 to be detected by the switching valve 10.

  As a result of the comparison, the pressure of the atmospheric gas G in the outer seal box 7 detected by the pressure gauge 11 during operation of the heat treatment furnace is such that the atmospheric gas G in the outer seal box 7 when the seal boxes 7 and 8 are normal. When the pressure rises by a predetermined amount or more than the pressure and approaches the atmospheric pressure (for example, the pressure difference from the atmospheric pressure is smaller than the pressure difference from the atmospheric gas G at normal time), the computer Determines that either the outer or inner seal box 7 or 8 surrounding the moving beam post 3 at the relevant location has been damaged and that there is intrusion air in the outer seal box 7, and that the heating furnace is abnormal due to the intrusion of air. A warning signal indicating the detection and the air intrusion point is output.

  Therefore, according to the heating furnace abnormality detection method of this embodiment, the presence / absence of intruding air can be determined, and the necessity of equipment repair can be determined. In addition, seal troughs and seal boxes are often inspected and are usually located in places that are difficult to inspect during operation, so it has been normal to continue operation without recognizing equipment abnormalities. According to the heating furnace abnormality detection method of this embodiment, the presence / absence of the intruding air can be easily and constantly monitored without extinguishing the furnace and taking the labor of visual inspection of the equipment. In addition, the soundness of the furnace body of the heating furnace can be achieved.

  FIG. 2 is an explanatory view showing an example of water seal breakage detection according to another embodiment of the heating furnace abnormality detection method of the present invention. In this embodiment, instead of the pressure gauge 11 in the previous embodiment, oxygen A concentration meter and a gas suction device are provided, and the atmospheric gas G in each outer seal box 7 is sucked by the gas suction device through the detection pipe 9 and the switching valve 10, and the oxygen concentration of the atmospheric gas G is measured by the oxygen concentration meter. From the result, the presence / absence of intruding air is determined based on whether or not the oxygen concentration is higher than a predetermined level than normal.

  In the example shown in the figure, for example, four heat treatment furnaces are arranged side by side, and two heat beam furnaces are arranged side by side, and a total of eight heat treatment furnaces are provided below the hearth 1 below the movement beams 2. Seal troughs 6 are respectively provided, and these seal troughs 6 are designated as No. 1-No. No. 8, for example, No. When any of the outer and inner seal boxes 7 and 8 immersed in the 1 seal trough is damaged, No. 1 which was about 2.10 to 2.60% under normal conditions. The oxygen concentration in the furnace near the 1 seal trough has risen to about 3.20 to 4.00%. If the detection threshold is set to 3.00% from the normal oxygen concentration for one seal trough, a significant increase in the oxygen concentration can be detected.

  Although the present invention has been described based on the embodiment, the present invention is not limited to the above-described example. For example, in the above-described embodiment, the pressure of the atmospheric gas G in the outer seal box 7 is detected by the pressure gauge 11 or the outside. The oxygen concentration in the seal box 7 is detected by an oxygen concentration meter to determine the presence or absence of intruding air. In addition to the pressure gauge 11, an oxygen concentration meter and a gas suction device are provided, and the pressure of the atmospheric gas G and oxygen You may make it determine the presence or absence of intrusion air based on both a density | concentration.

Further, in the above embodiment, the presence or absence of intruding air in all the outer seal boxes 7 respectively surrounding all the moving beam posts 3 is determined, but the inside of the heating furnace is divided into a plurality of sections, For at least one moving beam post, at least one of an oximeter and a pressure gauge may be connected to an outer seal box surrounding the moving beam post. The walking beam type heat treatment furnace may be configured such that the seal trough 6 is provided on the moving beam post 3 and moves together with the moving beam 2.

  Thus, according to the heating furnace abnormality detection method of the present invention, it is possible to determine the presence or absence of intruding air, determine whether or not equipment repair is necessary, and monitor the presence or absence of the intruding air without extinguishing the furnace and labor. Therefore, the soundness of the furnace body of the heating furnace can be ensured inexpensively and reliably.

DESCRIPTION OF SYMBOLS 1 Hearth 1a Opening part 2 Moving beam 3 Moving beam post 4 Walking beam drive frame 5 Lid 6 Seal trough 6a Opening part 7 Outer seal plate 8 Inner seal plate 9 Detection piping 10 Switching valve 11 Pressure gauge G Atmospheric gas

Claims (3)

The water seal is placed inside the seal box down into the seal trough, which is fixedly placed below the hearth from the position between the hearth opening and the seal trough opening of the moving beam post of the walking beam. Detects abnormalities due to air intrusion in a walking beam type heating furnace that has a double structure that surrounds the moving beam post from the periphery of the floor opening and is surrounded by an outer seal box lowered into the seal trough When doing
Connecting at least one of an oximeter and a pressure gauge to the outer seal box;
Compare the detection results of at least one of these oxygen concentration gauges and pressure gauges with that when the equipment is normal, and determine that there is intrusion air due to the perforation of the equipment when the detection results differ from the normal one by a predetermined amount or more A heating furnace abnormality detection method characterized by detecting an abnormality of the heating furnace. The heating furnace is divided into a plurality sections for the moving beam post of at least one in each compartment, to connect at least one of the oxygen concentration meter and a pressure gauge to the outer seal box surrounding the walking beam post The heating furnace abnormality detection method according to claim 1, wherein The other end of a plurality of pipes each having one end connected to the plurality of outer seal boxes is switched and connected to at least one of the oximeter and the pressure gauge. For detecting abnormalities in heating furnaces.

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