JP5780137B2 - Sealing mechanism for heating furnace opening - Google Patents

Description

  The present invention relates to a mechanism for sealing an opening on the charging side or extraction side of a heating furnace with a door that moves up and down.

  In the continuous heating furnace, the opening on the charging side and the extraction side are sealed with a door to prevent flame release. The door of a general heating furnace opens and closes an opening that forms a loading or extraction port of a slab formed in a furnace body of a heating furnace by raising and lowering a suspended elevator door. The elevating door is moved up and down by a sprocket positioned above the opening and having a shaft extending in the width direction above the opening and a chain wound around the sprocket.

  And the conventional elevator door is not a thing of the structure which presses a door against a furnace body with a cylinder in order to seal the opening part of a furnace body (patent document 1), or the said elevator door, but flexibility and heat resistance There exists a structure (patent document 2) of the structure covered with a characteristic shielding curtain. In addition, the gap between the elevator door and the furnace body is negative, that is, the elevator door is pressed against the furnace body, and the elevator door is moved up and down while sliding on the furnace body, or the lower part of the door A guide roller is provided and clamped, and the upper part of the door is sealed with a sand seal.

Japanese Utility Model Publication No. 56-8810 Japanese Utility Model Publication No. 61-137562

However, a structure in which the door is pressed against the furnace body by a cylinder or a guide roller provided at the lower part of the door and clamped and the upper part of the door is sealed with a sand seal operates to hold or fix the door. It is necessary to provide a separate mechanism, and there is a drawback that the structure and cost are increased. In addition, the shielding curtain covering the opening is severely deteriorated by the heat of the shielding curtain, and it is difficult to withstand the internal pressure due to its flexibility, so it cannot be used for a heating furnace in which the furnace pressure is set high. There is a problem that. Furthermore, in the structure where the elevator door is moved up and down while sliding the elevator door against the furnace body, the wear of the refractory constituting the furnace body is significant and the fuel consumption is deteriorated due to the flame release. There is a problem that the frequency of repairs becomes high.
Therefore, the present invention suppresses the wear of the furnace body to improve the fuel consumption and reduce the repair frequency without requiring a special device for pressing the door, and further suppresses deterioration due to heat and increases the internal pressure. It is an object of the present invention to provide a sealing mechanism capable of

  The sealing mechanism for the opening of the heating furnace according to one aspect of the present invention opens and closes the opening that forms the loading or extraction port of the slab formed in the furnace body of the heating furnace by raising and lowering the suspended elevator door. A sprocket having a shaft extending along the width direction of the furnace body at a position above the opening of the furnace body and behind the front surface of the furnace body in which the opening is opened. A chain that is wound around the sprocket and has a lower part connected to the upper part of the elevator door, and the sprocket is an eccentric sprocket in which the shaft is eccentric from the center of the sprocket. The center position of the sprocket is positioned in front of the opening portion with respect to the shaft, and the center position of the sprocket is more than the shaft portion with respect to the shaft when the opening portion is closed by lowering the elevating door. By positioning the rear, the lift door in the closed position is in contact with the furnace body around the opening, the lifting door in the open position is characterized in that the away the front opening from the furnace body.

In the sealing mechanism, the front-rear direction of the opening from the position of the furnace body side surface of the elevator door in the open position to the front surface position where the opening of the furnace body in contact with the surface in the closed position is open Is preferably set to a distance smaller than the difference in eccentric distance in the same direction of the sprocket.
The sprocket may be one that is fixed so as to rotate integrally with the shaft disposed on the upper side of the furnace body.

  In the said aspect of this invention, since the sprocket which raises / lowers a raising / lowering door was eccentric, a door can be hold | maintained to a furnace body, without requiring the special apparatus for pressing a door. Further, since the elevator door is opened and separated from the furnace body, the wear of the furnace body is suppressed to prevent flame release, so that the fuel consumption can be improved and the repair frequency can be reduced. Furthermore, since it is not necessary to make the door flexible, the door can be made sufficiently heat-resistant and pressure-resistant.

The front view of embodiment. XX sectional drawing of FIG. (A) is the YY sectional view taken on the line of FIG. (B) is sectional drawing of the state which the raising / lowering door of (a) raised. FIG. 4 is a table showing numerical values such as positions in FIG. The graph which shows the relationship between the height of a pass line, and the clearance gap between doors. Explanatory drawing which shows the difference of the eccentric distance of a sprocket, and the clearance gap between doors.

  FIG. 1 is a front view of a furnace body 1 of a continuous heating furnace. The furnace body 1 is mainly formed by assembling a refractory material, and shows a state in which the front surface of the opening 2 forming the inlet or extraction port of the slab formed in the furnace body 1 is closed by the elevating door 3. . The elevating door 3 is made of steel, and a refractory material is disposed on the surface on the furnace body 1 side, and is suspended by each chain 5 wound around a plurality of sprockets 4. Each sprocket 4 is fixed to one rotating shaft 6, and each sprocket 4 rotates integrally by the rotation of this rotating shaft 6. Therefore, since the axis of the rotating shaft 6 forms the axis of the sprocket 4, the following description will be made without distinguishing the rotating shaft 6 and the axis of the sprocket 4 in principle.

The rotating shaft 6 is rotatably supported via a bearing 7 on a fixed body such as a beam (not shown) fixed to the furnace body 1 or the building where the furnace body 1 is located, and one end of the rotating shaft 6 is connected via a speed reducer 8. This is also connected to a drive motor 9 supported by the fixed material.
Another sprocket 11 is fixed to the rotary shaft 6 with its central axis coinciding with the rotary shaft 6, and this sprocket 11 also rotates integrally with the rotary shaft 6. A counterweight 13 is suspended from the sprocket 11 via a chain 12 at a position that does not interfere with the furnace body 1 and peripheral devices. The counterweight 13 balances with the lift door 3 and reduces the load on the drive motor 9 and the speed reducer 8 when the lift door 3 is raised and lowered.

  The rotating shaft 6 is disposed above the opening 2 of the furnace body 1 and behind the front surface 1a of the furnace body 1 in which the opening 2 is opened, and is fixed to the rotating shaft 6 via the chain 5. The sprocket 4 that suspends the elevating door 3 is an eccentric sprocket. That is, at the opening position of the opening 2 due to the lifting of the lift door 3, the center 4a position of the sprocket 4 is positioned in front of the opening 2 with respect to the rotating shaft 6, as shown in FIG. ing. Further, in the closed position of the opening 2 due to the lowering of the elevating door 3, as shown in FIG. 3A, the position of the center 4a of the sprocket 4 is positioned behind the opening 2 with respect to the rotary shaft 6. It has become.

In FIG. 3, the eccentric distance A of the sprocket 4 is small at the closed position of the lift door 3, and the eccentric distance A of the sprocket 4 is large at the open position of the lift door 3, and when the eccentric distance A is large, the furnace body 1 and the lift door. 3 is large and the eccentric distance A is small, the gap B is small (zero).
To further explain this point, the position of the surface on the furnace body 1 side of the elevator door 3 in the open position of FIG. 3 (b), and the front surface 1a where the opening 2 of the furnace body 1 in contact with this surface is opened. The distance in the front-rear direction of the opening (same as the gap B) is the difference in the eccentric distance in the same direction of the sprocket 4 (the eccentric distance A in FIG. 3B and the eccentric distance A in FIG. 3A). The difference is set to a smaller distance.

  With the above configuration, the opening sealing mechanism operates as follows. First, since the eccentric distance A of the sprocket 4 is large at the open position of the elevator door 3 shown in FIG. 3B, the elevator door 3 is greatly increased forward from the front surface 1a where the opening 2 of the furnace body 1 is provided. It is separated and the gap B is wide. When the elevating door 3 is lowered with the rotation of the rotary shaft 6 and the sprocket 4, the eccentric distance A of the sprocket 4 is gradually reduced, so that the gap B is gradually reduced and the elevating door 3 is opened to the furnace body 1. Approach part 2. Before the lowering of the lifting door 3 is finished, the lifting door 3 comes into contact with the front surface 1a of the furnace body 1 with the opening 2 and moves down while sliding on the front surface 1a of the opening 2 of the furnace body 1 to reach the bottom dead center. .

Here, since there is a relationship between the eccentric distances A and the gaps B when the lift door 3 is in the open position and the closed position, the lift door 3 is in the middle stage before reaching the bottom dead center. It contacts the front surface 1a of the opening 2 of the furnace body 1 and slides as it is to reach the bottom dead center. During this sliding, if the furnace body 1 is not present, the elevator door 3 further moves in the depth direction of the furnace body 1, that is, the gap B is negative. And that the gap B becomes negative means that the elevating door 3 is pressed against the front surface 1a of the opening 2 of the furnace body 1 and descends, and the opening 2 is sealed.
On the contrary, when the elevator door 3 is raised, the elevator door 3 at the bottom dead center starts to rise and is slid against the front surface 1a of the opening 2 of the furnace body 1 for a short time. However, after that, the gap B becomes positive, and the elevator door 3 is raised and the opening 2 is opened while the gap B is gradually increased.

  The raising / lowering of the lifting / lowering door 3 uses the driving force of the motor 9 in any direction, but the rotation of the rotary shaft 6 to one side of the lifting / lowering depends on the balance between the lifting / lowering door 3 and the counterweight 13. It cannot depend on the driving force of the motor 9. For example, the driving force of the motor 9 is used to raise the elevator door 3, but the elevator door 3 may be lowered by its own weight. In this case, the balance is set so that the elevating door 3 can be lowered at a low speed. Since the eccentric distance A is large as shown in FIG. 3B at the raised position of the elevator door 3, the rotational moment applied to the sprocket 4 is also increased, and the elevator door 3 is lowered at a relatively high speed at first. To do. However, since the eccentric distance A is eventually reduced by the rotation of the sprocket 4, the rotational moment is gradually reduced, and the lowering speed of the elevating door 3 is decreased. Therefore, when the elevating door 3 comes into contact with the front surface 1a of the opening 2 of the furnace body 1, the speed is considerably reduced, and it slides as it is to reach the bottom dead center.

  Thus, when the lifting door 3 is lowered by its own weight, the distance at which the lifting / lowering door 3 slides on the furnace body 1 is earlier because the clearance B is earlier at the beginning and lowering at the lowest speed when the clearance B disappears. Therefore, the wear of the refractory material of the furnace body 1 and the elevator door 3 can be suppressed. Moreover, since the lowering of the lifting / lowering door 3 is quick while the lifting / lowering door 3 is away from the furnace body 1, the speed of closing the lifting / lowering door 3 is also increased.

  FIG. 4 is a table showing the relationship between the conditions of the sprocket 4 of the embodiment and the height of the lifting door 3 (pass line level difference), etc. According to this, the diameter of the sprocket 4 is 815 mm, the eccentricity of the sprocket 4, That is, the deviation between the shaft 6 (rotation center) of the sprocket 4 and the center position 4a of the sprocket 4 is 25 mm. Therefore, the maximum value of the eccentric distance A shown in FIGS. 3 and 6 is 432.5 mm, the minimum value is 382.5 mm, and the difference (theoretical gap B) is 50 mm.

On the other hand, the distance in the front-rear direction of the opening between the position of the surface on the furnace body 1 side of the elevator door 3 in the open position and the position of the front surface 1a where the opening 2 of the furnace body 1 is in contact with this surface. The gap Ba is set to 40 mm when the gap Ba is in effect. Therefore, a difference of 10 mm between the theoretical size of the gap B and the actual size of the gap Ba is a minus amount of the theoretical gap B.
Therefore, in this embodiment, in addition to the eccentric distance A and the gap B at each lift position (pass line level difference) of the lift door 3 by the rotation of the sprocket 4, the winding angle and winding of the chain 5 around the sprocket 4 The length relationship is as shown in FIG. Further, the relationship between the pass line level difference (that is, the height position of the lift door 3) and the gap B at this time is shown in the graph of FIG. 5 in comparison with the conventional structure.

Here, the negative part of the theoretical gap B is 10 mm at the maximum as described above, and this negative part is the distance of the lower quarter of the lifting distance of the lifting door 3. For this reason, the lift door 3 is in sliding contact with the furnace body 1 in about a quarter of the lift distance. In addition, since the minus portion is 10 mm in the closed state, the elevator door 3 is pressed against the furnace body 1 by its own weight, so the opening 2 is sealed, so that no other special equipment is used. , Flame release can be suppressed.
In addition, since each numerical value in the said embodiment and an Example is only an example for demonstrating this invention, this invention is not restrict | limited by these.

1 Furnace 1a Front 2 Opening 3 Lifting Door 4 Sprocket (Eccentric Sprocket)
5 Chain 6 Rotating shaft A Eccentric distance B Clearance Ba Virtual clearance

Claims (3)

  In a sealing mechanism for an opening of a heating furnace that opens and closes an opening that forms a loading or extraction port of a slab formed in the furnace body of a heating furnace by raising and lowering a suspended elevator door, the shaft is connected to the furnace body A sprocket extending along the width direction of the furnace body behind the front surface of the furnace body in which the opening is opened, and a lower part connected to the upper part of the elevator door while being wound around the sprocket The sprocket is an eccentric sprocket in which the shaft is decentered from the center of the sprocket, and the center position of the sprocket is more forward than the shaft than the shaft when the opening is opened by raising and lowering the lifting door. In the closed position of the opening due to the lowering of the lifting door, the center position of the sprocket is positioned behind the opening with respect to the shaft, and the lifting door is in the closed position. Mouth contacting the periphery of the furnace body, the sealing mechanism of the opening of the furnace in which the lift door in the open position is characterized in that the away the front opening from the furnace body.   The distance in the front-rear direction of the opening from the position of the furnace body side surface of the elevator door in the open position to the front surface position where the opening of the furnace body in contact with the surface in the closed position is opened is the sprocket. The opening mechanism of the heating furnace according to claim 1, wherein the distance is set to be smaller than a difference in eccentric distance in the same direction. The sealing mechanism for the opening of the heating furnace according to claim 1 or 2, wherein the sprocket is fixed so as to rotate integrally with the shaft disposed on the upper side of the furnace body.

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