JP6447550B2 - Hearth sealing device for walking beam heating furnace and walking beam heating furnace - Google Patents

Description

  The present invention relates to a hearth seal trough structure of a walking beam type heating furnace, and more particularly to a hearth seal device for a walking beam type heating furnace and a walking beam type heating furnace.

  In the heating furnace, the exhaust gas in the heating furnace flows out into the flue without excess and deficiency, and the pressure in the heating furnace (also referred to as the furnace pressure) is controlled so that air does not enter the furnace. If the furnace pressure is set to a pressure lower than atmospheric pressure (negative pressure), the atmosphere will be sucked in from the charging door or extraction door of the heated material and the inside of the furnace will be cooled. A lot of fuel is used to make the same furnace temperature.

  On the contrary, if the furnace pressure is set to a pressure higher than atmospheric pressure (positive pressure), exhaust gas is ejected from the charging door or extraction door, and the equipment around the door is burned out or flows into the flue. By reducing the amount of exhaust gas, the efficiency of the installed waste heat recovery device is reduced.

  On the other hand, the walking beam heating furnace has a structure in which the moving skid is moved in the vertical direction and the slab conveying direction, and therefore there is an opening in the hearth for moving the moving skid. In the heating furnace, the internal temperature rises to about 1300 ° C., so there is a pressure distribution in the furnace, with the upper part being a positive pressure and the lower part being a negative pressure. For this reason, a negative pressure is generated at the opening below the moving skid post, and air is sucked from the surroundings.

  FIG. 1 is a view showing a hearth seal structure of a conventional walking beam heating furnace. For example, FIG. 1 shows a cross section of the lower part of the hearth of the walking beam heating furnace disclosed in Patent Document 1, where 1 is the hearth, 2 is a moving skid post, 3 is a seal box, 4 is Seal troughs and 5 represent water, respectively. The reference numerals 1, 3, 4 and the arrow A are attached only to the right side of the figure and omitted on the left side of the figure, but are assumed to be similarly attached to the left side of the figure.

  The conventional hearth seal structure is provided with a seal trough 4 which is a container filled with water 5 on the moving skid side. A flat plate called a seal box 3 for sealing is installed from the hearth 1 to the bottom of the water surface in the seal trough 4 to seal the inside and outside of the heating furnace with water.

  Patent Document 2 discloses a technique for sealing an opening by providing a sliding plate on the lower surface of the hearth and sliding it.

  Further, Patent Document 3 discloses a technique including an upper seal box made of a steel plate and a lower seal box made of a heat-resistant flexible sheet that is immersed in the water of a seal trough at the lower end of the upper seal box.

Japanese Utility Model Publication No. 63-8742 Japanese Patent Publication No. 63-17889 JP 2002-294332 A

  The present inventors have found through investigation that the occurrence of corrosion is large in the draft portion (the water surface position of the seal trough 4, indicated by the arrow portion A in FIG. 1) on the outer surface of the seal box 3.

  This is because “iron” which is the material of the seal box 3, “water” for water sealing, and “atmosphere” outside the heating furnace are in contact with the outer surface of the seal box 3. Note that, on the inside of the heating furnace, the oxygen concentration inside the heating furnace is kept low, so that the corrosion is not as remarkable as the portion A.

  If the corrosion of the outer surface of the seal box proceeds and reaches the inside and a hole is formed in the seal box, the inside and outside of the furnace cannot be sealed, and the atmosphere is sucked into the heating furnace. Even if a hole is formed in the seal box, water leakage does not occur unlike the seal trough, and it is difficult to notice the hole in the seal box immediately from the outside.

  For this reason, the repair is delayed and the corrosion further progresses. Although it can be detected by an external method only when it affects the oxygen concentration in the furnace, the fuel intensity has already deteriorated at this stage.

  The technique disclosed in Patent Document 1 described above has the above-described corrosion problem. Further, in the method of mechanically contacting and sealing like the technique disclosed in Patent Document 2, there is a high possibility of causing malfunction of the skid itself due to biting of a scale falling from the inside of the heating furnace, This is not an effective method because it can cause trouble for the sealing.

  Furthermore, although the technique disclosed in Patent Document 3 is considered to be effective for preventing corrosion inside the furnace of the sealed box, the above-mentioned corrosion occurs on the atmosphere side. There is a problem that cannot be prevented.

  The present invention has been made in view of such circumstances, and does not directly connect the inside and outside of the heating furnace due to corrosion in the seal box, and can determine the perforation due to corrosion. It is an object of the present invention to provide a walking beam heating furnace hearth sealing device and a walking beam heating furnace that do not reduce the fuel consumption rate.

  The above problems can be solved by the following invention.

[1] A hearth sealing device for a walking beam type heating furnace,
Seal trough with water on the moving beam side,
A seal box formed by molding the lower end of a flat plate for sealing installed from the hearth toward the seal trough in the lower direction into a U-shape;
A hearth sealing device for a walking beam type heating furnace.

[2] In the hearth sealing device for a walking beam type heating furnace according to [1] above,
A water level sensor installed inside the U-shape of the seal box;
A hearth sealing device for a walking beam type heating furnace.

  [3] A walking beam heating furnace comprising the hearth sealing device for a walking beam heating furnace according to [1] or [2].

  According to the present invention, water in the seal trough is reduced even if a hole is opened due to corrosion at the place where the atmosphere, water, and air come into contact, but the inside of the furnace and the outside of the furnace are not connected. Never inhale.

  On the other hand, if a hole is opened inside the U-shaped inside of the seal box, water may stay inside, which may cause corrosion. Therefore, a water level sensor is installed inside so that it can be easily determined that a hole has been opened as viewed from the outside, and repair can be performed before the atmosphere is sucked into the furnace.

  Moreover, by applying the hearth sealing device of the walking beam type heating furnace according to the present invention to the walking beam type heating furnace, it is possible to delay the corrosion perforation of the seal box and further clarify whether repair is necessary. Thus, the fuel consumption rate of the heating furnace can be prevented from being lowered.

It is a figure which shows the hearth seal structure of the conventional walking beam type heating furnace. It is a figure which shows the structural example of the hearth sealing apparatus of the walking beam type heating furnace which concerns on this invention. It is a figure which shows an example of the result of having measured the corrosion thinning amount of the seal box.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings and mathematical formulas. FIG. 2 is a diagram showing a configuration example of a hearth sealing device for a walking beam heating furnace according to the present invention. In the figure, 6 represents a water level sensor, and the other symbols are the same as in FIG.

  In the present invention, in the seal box 3, the lower end of the flat plate for sealing installed from the hearth 1 to the seal trough 4 in the lower direction is formed in a U shape. And the water level sensor 6 is installed in the U-shaped inside of the seal box 3.

  The U-shaped seal box is the part where the three interfaces of “atmosphere”, “iron”, and “water” that are most susceptible to corrosion are in contact (indicated by arrow C in FIG. 2). This is to prevent air from being sucked into the furnace even if a hole is formed. As shown in FIG. 2, the U-shape refers to a shape that can divide the water surface of the seal trough 4 to form a space where water does not enter the divided inner surface. And so on.

  However, if perforation occurs due to corrosion at the arrow C, water may accumulate in the inner portion of the U-shape, and further internal corrosion may occur. Therefore, the water level sensor 6 (the left and right sides of the movable skid post 2 are also symmetrical with respect to the moving skid post 2 in FIG. 2 so that the perforation inside can be detected, and the water level sensor on the right side of FIG. 6 is omitted).

  As the water level sensor 6, for example, any type or detection method such as a method of measuring the position of the float with an operating transformer may be used.

  As described above, since the water level sensor is provided so that the perforation inside the U-shape can be detected, it is possible to quickly detect the stagnation of water and perform quick repair.

  As described above, according to the present invention, even if a hole is formed due to corrosion at a place where air, water, and air come into contact, the water in the seal trough is reduced, but the inside of the furnace and the outside of the furnace are not connected. Do not breathe in.

  On the other hand, if a hole is opened inside the U-shaped inside of the seal box, water may stay inside, which may cause corrosion. Therefore, if a water level sensor is installed in the interior and an alarm is issued, for example, with a buzzer, it can be easily known that a hole has opened, and repair can be performed before the atmosphere is sucked into the furnace. it can.

  FIG. 3 is a diagram illustrating an example of a result of measuring the corrosion thinning amount of the seal box. The transition of the corrosion thinning amount in the conventional portion A in FIG. 1, the portion B in FIG. 2 of the present invention (the portion corresponding to the position A in FIG. 1) and the portion C was examined over the course of five years. It is a result.

  In the conventional method, the corrosion reduction of 10 mm is observed after 5 years in the portion A, whereas in the portion B of the present invention, only the corrosion reduction is 2 mm. Can be seen to drop significantly.

  However, in part C of the present invention, 9 mm of corrosion thinning is observed as in part A of the conventional method. For this reason, corrosion occurs inside the U-shape and water may eventually flow out.

  Because water leaks, a water level sensor is installed inside, and it is possible to judge the timing of repair when water flows out.

  Also, by applying the walking beam type furnace hearth sealing device according to the present invention to the walking beam type heating furnace, it is possible to delay the corrosion perforation of the seal box and clarify whether repair is necessary. Thus, the fuel consumption rate of the heating furnace can be prevented from being lowered.

1 hearth 2 moving skid post 3 seal box 4 seal trough 5 water 6 water level sensor

Claims (3)

A hearth sealing device for a walking beam heating furnace,
Seal trough with water on the moving beam side,
A seal box formed by bending the lower end of a sealing plate installed from the hearth to the lower side of the seal trough, and bending it to the opposite side of the skid post, and forming a U-shape;
Equipped with,
In order to prevent water from entering the U-shaped inner surface side of the seal box, the height position of the upper end of the U-shaped portion is higher than the water surface of the seal trough, and A hearth sealing device for a walking beam type heating furnace, wherein a longitudinal end portion of the furnace of the letter-shaped portion is closed . In the hearth sealing device of the walking beam type heating furnace according to claim 1,
A water level sensor installed inside the U-shape of the seal box;
A hearth sealing device for a walking beam type heating furnace. A walking beam heating furnace comprising the hearth sealing device for a walking beam heating furnace according to claim 1.