JPH07190624A - Furnace lid retaining device for electrode rotating system electric furnace - Google Patents

Abstract

PURPOSE:To provide a furnace lid retaining device for an electric furnace, which can turn and move the position of an electrode under excitation without moving the furnace lid. CONSTITUTION:In an electric furnace with lid of electrode rotating system provided on an inclinable floor 10, a rotary floor 22, positioned on the inclinable floor 10 and moving reversibly on a concentric circle having the center thereof on the central axis of the furnace, a GAMMA(ge<->)-type furnace lid retaining beam 30, whose lower end is fixed to the rotary floor 22, are provided while the horizontal tip end of the GAMMA-type furnace lid retaining beam 30 is provided with wheels 52, 53, sliding on rails 41 established on the inclinable floor 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arc type electric furnace used for melting iron or non-ferrous metal scrap, hot briquette iron, etc. and refining pig iron. The present invention relates to a so-called electrode swivel type electric furnace holding device for a furnace lid. Incidentally, in recent years, referred to as a ladle furnace, there is a facility for arranging an electrode for generating a three-phase alternating current arc on a ladle and adjusting the temperature of the molten metal in the ladle. Shall be regarded as a three-phase AC arc type electric furnace.

[0002]

2. Description of the Related Art A three-phase alternating current arc type electric furnace has an electrically conductive content which is prepared by suspending electrodes formed by compacting three graphite powders from above the furnace body and charging the electrodes and the inside of the furnace. A voltage is applied between the two to generate an arc, and the high heat of the arc heats and melts the contents of the furnace. The ladle furnace uses the principle of this arc heat generation for maintaining or adjusting the temperature of the molten metal in a ladle with a lid. The reason why three-phase alternating current is used in these electric furnaces is that it is most common to generate and transmit power in three phases for a normal commercial power source.

On the other hand, with the recent development of thyristors, the use of a DC electric furnace has become widespread for melting and refining metal scrap. However, it is simpler around the electrodes on the furnace than the AC electric furnace and the electrodes and This is because it can be expected to reduce power consumption and flicker. However, since the DC electric furnace has a bottom electrode, there are problems that the equipment cost is high and that maintenance of the bottom electrode is time-consuming. Therefore, if the occurrence of a part that becomes colder than the surroundings) is prevented, there is still room for reviewing the use of the AC electric furnace.

By the way, as described above, in the three-phase AC arc type electric furnace, the three electrodes 4 are arranged on the furnace (see FIG. 6). Since the distance to the wall 5 takes various values depending on the position of the furnace wall 5,
The furnace wall temperature at a position distant from the electrode 4 is lower than the others, and there is a drawback that the melting speed of the furnace contents present in this portion (so-called cold spot 44) is slow. That is,
The presence of the cold spot 44 partially slows down the melting speed of the material to be melted in the furnace, and the operating time of the furnace depends on the melting speed of this portion. Therefore, the electric furnace aiming at high efficiency in recent years Is not very good for Even in a DC electric furnace (not shown), the degree is slight compared with the case of using the cold spot 44 of the AC electric furnace, but it occurs due to the arrangement of conductors from the rectifier to the furnace upper and lower electrodes. A non-uniform melting phenomenon may occur due to the arc deflection phenomenon caused by the electromagnetic force. Also,
In a ladle furnace (not shown), unlike the three-phase AC arc electric furnace, since the content of the ladle is molten steel, the heterogeneous melting phenomenon caused by the cold spot does not pose a problem in operation. However, since there is not a large amount of slag inside the ladle, the arc is apt to be bare, and the heat from the arc is transferred to the wall of the ladle, and conversely the wall closer to the electrode is more likely to melt away than the part far away. There is. Traditionally,
In the three-phase AC electric furnace, the formula for experimentally calculating the coefficient a indicating the size of the refractory melting loss is generalized as follows: a = (input power × arc voltage) / electrode surface The shortest distance from the furnace wall to the furnace wall can be seen from the content of this equation.

Therefore, in AC and DC arc type electric furnaces and ladle furnaces, the electrodes installed on the furnace are turned around the center of the furnace to energize while changing various distances from the electrodes to the furnace wall. If the effects of heat can be averaged in each part, it is expected that the profits obtained will be large. That is, if the electrode can be reversibly moved within a certain angle range around the vertical axis passing through the center of the furnace, the distance between the electrode and the furnace wall can be changed and the cold spot can be eliminated. It should be possible. In particular, if the electrodes can be moved moment by moment, the distance between the electrodes and the furnace wall will be constant on average throughout each operation period, and the arc heat applied to the furnace wall will be averaged. In particular,
If you draw a virtual concentric circle around the center axis of the furnace on the outside of the furnace and move the electrode holding means along this concentric circle, the electrodes fixed to the electrode holding means will also rotate around the center of the furnace. It will move as an axis, and the purpose can be achieved.

This idea is already known and is disclosed in JP-A-60-
No. 232478, "Arc Type Electric Furnace",
"Scrap Arc Melting Furnace" of 0-259885
Examples are disclosed in. However, in the above-mentioned publication, regarding the actual movement of the electrode holding means of the electric furnace, it is necessary to consider the connection with the hanging means of the furnace lid, but no reference is made to this connection. In other words, it is necessary to turn the furnace lid at the same time as turning the electrode. The weight of the furnace lid overlaps with the weight of the furnace lid itself, the weight of cooling water, the weight of the metal attached to the lid, etc., and sometimes becomes 10 tons or more in a 50 ton electric furnace. It is usually relatively easy to swivel such heavy objects, but it is difficult to stop due to inertia. In other words, even if the electrode stops swirling when the swirl is stopped, the swirl of the furnace lid cannot be stopped, and there is a high possibility that the electrode will come into contact with the furnace lid and damage the electrode. Further, metal may adhere to the lower surface of the furnace lid, and it becomes necessary to keep the distance between the furnace body and the furnace lid in order to turn the furnace lid. By keeping the distance from the furnace body, heat is dissipated between the furnace body and the furnace lid, and the furnace lid becomes meaningless. In addition, it is difficult to swivel the furnace lid itself because the metal that diverges from the inside of the furnace solidifies and fixes the furnace body and the furnace lid, and the above idea has not been realized.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a furnace lid holding device that can swivel and move an electrode position during energization without moving the furnace lid. To aim. In addition, the present invention, when charging raw materials,
It is also an object of the present invention to provide a furnace lid holding device in which the lifting force is first transmitted to the furnace lid when the furnace lid is opened and removed from the furnace body. Further, the present invention provides a furnace lid holding device capable of reducing the weight of the entire mechanism by having a mechanism for retracting a rail supporting one end of the furnace lid holding beam when the furnace is tilted by tapping steel or the like. It is also intended to be provided.

[0008]

In order to achieve the above-mentioned object, the inventor has reviewed the drawbacks of the technique described in the above-mentioned Japanese Patent Laid-Open Publication, and for example, simplifies and reduces the weight of the furnace lid holding means, The present invention has been completed by incorporating a new idea such that the furnace lid support beam is supported at both ends. That is, the present invention, in a covered electric furnace of an electrode swirl system provided on a tilting bed, a swirl floor reversibly moving on a concentric circle centered on the central axis of the furnace on the tilt bed, and on the swirl floor A Γ-shaped furnace lid holding beam having a fixed lower end, and a wheel that slides on a rail erected on the tilting floor are provided at the tip of the horizontal portion of the Г-shaped furnace lid holding beam. It is a furnace lid holding device for an electrode swirl type electric furnace. Further, the present invention is a furnace lid elevating means fixed to the Г type furnace lid holding beam,
A chain for suspending the furnace lid via a pulley by the furnace lid elevating means, and a slidable ring-shaped hanger at the tip of the chain for engaging with a circular holding ring provided on the furnace lid. It is also the furnace lid holding device of the electrode swirl type electric furnace according to claim 1. Further, the present invention provides a wheel sliding on a concentric rail centering on the central axis of the furnace lid turning means at the tip of the horizontal portion of the Γ-shaped furnace lid holding beam for charging raw materials. It is the electrode swivel type furnace lid holding device according to claim 1 or 2, characterized in that, due to the tilting of the furnace body,
The means for retracting part of the rail according to claim 3 is provided at a position where interference between the rail according to claim 3 and the beam for holding the Γ-shaped furnace lid can be avoided. Is a furnace lid holding device for an electrode swirl type electric furnace.

[0009]

According to the present invention, a furnace lid holding device for an electrode swirl type covered electric furnace provided on a tilting bed is provided with a swirling bed which reversibly moves on a concentric circle centered on the central axis of the furnace body on the tilting bed. Since the Γ-shaped furnace lid holding beam whose lower end is fixed on the swivel floor, and the tip of the horizontal portion of the furnace lid holding beam are provided with wheels sliding on the rails erected on the tilting floor, The electrodes can be reversibly swung within a certain angular range while the electric furnace is energized. Further, in the present invention, in addition to the furnace lid holding device, a furnace lid lifting means fixed to the Γ-shaped furnace lid holding beam, a chain for hanging the furnace lid via a pulley by the furnace lid lifting means, Since a circular retaining ring provided on the furnace lid and a slidable ring-shaped suspending tool that locks the chain are provided at the tip of the chain, even if the electrode is swung or moved, the position of the chain only changes. Thus, it is possible to rotate only the electrode without moving the furnace lid. Further, in the present invention,
For raw material charging, etc., wheels sliding on concentric rails centering on the central axis of the furnace lid turning means were provided at the tip of the horizontal portion of the Γ-shaped furnace lid holding beam. It becomes easy to move the furnace lid from the furnace body by opening the furnace upper part at the time of charging, and when the furnace body is tilted, the rail and the Γ-shaped furnace lid holding beam are prevented from interfering with each other. Since a means for retracting a part of the rail according to claim 3 is provided at a position that can be avoided, it is possible to combine the complicated functions of tilting the furnace body and opening the upper part of the furnace. Hereinafter, the details of the present invention will be described with reference to FIGS.

[0010]

EXAMPLE First, FIG. 4 shows a vertical cross section of an electric furnace provided with a "furnace lid holding device for an electrode swirl type electric furnace" according to the present invention.
The dotted line drawing in FIG. 4 represents the tilting state of the furnace body 1. In addition, in FIG. 4, the “furnace lid holding beam 3 according to the present invention is shown.
"0" and "chain 33 for hanging the furnace lid and ring-shaped hanger 31"
Is also shown.

When energized, a furnace lid 2 is placed on the furnace body 1 of the electric furnace, and the furnace lid 2 covers the furnace opening and plays a role of preventing heat dissipation. An opening 3 is formed in the center of the furnace lid 2, and an electrode 4 is inserted into the furnace from the upper part of the furnace. In an ordinary electric furnace, a refractory non-conductor (not shown) called a small ceiling is installed in order to prevent the electrode 4 from electrically connecting to the furnace lid 2. In an ordinary electric furnace having three electrodes 4, three holes are formed in this small ceiling, and efforts are made to make the opening 3 portion as small as possible. However, in this embodiment, three openings 3 are not provided for each electrode 4, and only one is provided for the three electrodes 4.

Further, the furnace body 1 of the electric furnace is also provided with two openings 7 and 8. The opening 7 is a slag discharge hole, and the degree of opening can be adjusted by a slag door 9 which moves up and down. ing. On the other hand, the opening 8 is the tap hole 8 and is used for the purpose of discharging the metal melted and refined in the furnace from the furnace. Further, the furnace body 1 is installed on a tilting floor 10, and the tilting floor 10 can be tilted to the slag door 9 side or the tapping hole 8 side at the opposite position by a tilting hydraulic cylinder 11. . And this tilting floor 1
The electrode elevating means 12 is stacked on the 0, and thereby the three electrodes 4 supported by the electrode holding means 50 are individually moved up and down. In addition, the electrode elevating means 12 itself is the tilting floor 10.
Since it is fixed on top of the
Will also be tilted.

Next, the operation of the "furnace lid holding device for an electrode swirl type electric furnace" according to the present invention during energization will be described. Therefore, a longitudinal section of the device is shown in FIG. 1 and an overall plane is shown in FIG. Lines indicated by symbols U, V, W, and Z in FIG. 2 are virtual concentric circles centered on the central axis X of the furnace body 1, that is, the center of the arrangement of the electrodes 4, respectively. The arrangement of the various means described is useful for understanding.

As is apparent from FIGS. 1 and 2, one set of electrode elevating means 12 is provided for each of the three electrodes, and each electrode elevating means 12 has a winch 13 and a columnar elevating portion 16. , A ring-shaped fixed portion 19. The electrode elevating means 12 are installed on a swivel floor 22 arranged on the tilting floor 10. The swirl bed 22 is capable of reversibly moving on the concentric circles W and Z centering on the central axis X of the furnace body 1 (range of about 60 °). This is done by moving wheels 24 attached to the lower surface on rails (not shown). The movement is performed by fixing the guide 25 along the concentric circle V, the guide roll 48 fixed to the swivel floor 22 movable along the surface of the guide 25 without frictional resistance, and the guide 25. The smoothness is ensured by the rack 26 that follows the concentric circle V that is present, and this is performed by the electrode turning means 29 that is fixed to the turning floor 22 and that includes the motor 27 and the pinion 28. Therefore, the electrode elevating means 12 moves on a virtual concentric circle centered on the central axis X of the furnace body 1 while holding the electrode 4 by the electrode holding means 50.

On the other hand, the Γ-shaped furnace lid holding beam 30 is installed on the swivel floor 22 with its lower end fixed, and the tip of the horizontal portion is erected on the tilting bed 10 along the concentric circle U shown in FIG. The rail 47 is slid on the rails 47 via wheels 52. The rail 47 tilts together with the furnace body 1 and the Γ-shaped furnace lid holding beam 30, and even when the electrode 4 is moved, the wheels 52 and the rail 47 cause the Γ-shaped furnace lid holding beam 30 to move.
Will be supported.

In this embodiment, there are two Γ-shaped furnace lid holding beams, as shown in FIG. Further, the furnace lid 2 is provided with a holding ring 32 which is concentric with the center axis X of the furnace body 1 as a center. This retaining ring 32,
The ring-shaped hanging tool 31 attached to the tip of the furnace lid suspension chain 33 suspended from the furnace lid holding beam 30
The electrodes are placed in a slidable relationship with each other during the pivotal movement. As a result, even if the Γ-shaped furnace lid holding beam 30 acts with the electrode when the electrode 4 moves, the furnace lid suspension chain 33
The state in which the furnace lid 2 is placed on the furnace body 1 can be maintained only by changing the position of. Figure 5 shows how the position of the chain changes. In FIG. 5, symbols D, E, F, and G are chain positions when the swivel floor 22 is on the lower side, and when swivel floor 22 is swung 30 ° to the right, symbols are at positions K, L, M, and N. Become.

From the above, it will be clear that the position of the electrode 4 can be changed by swiveling the swirl floor 22 without moving the furnace lid over the furnace. The last is an embodiment of the "furnace lid holding device" according to the present invention when it is necessary to open the upper part of the furnace body 1 for charging raw materials. The opening of the upper part of the furnace is to move the furnace lid 2 from the furnace body 1. Therefore, the shaft 0 on the swivel floor shown in FIG.
A rail 41 is arranged on an imaginary concentric circle Y centered on (the center of the furnace lid turning means 40).

In the present invention, a wheel 53, which is provided at the tip of the horizontal portion of the Γ-shaped furnace lid holding beam 30 and is different from the wheel 52 used for turning the electrode, slides on the rail 41 while the wheel 53 slides on the rail 41.
One end of the mold furnace lid holding beam 30 can be supported. A part of the rail 41 can be retracted to a position where it does not interfere with the beam itself when the furnace body is tilted, and a cylinder 43 is installed as a means thereof.

In order to move the furnace lid 2 from above the furnace, it is necessary to lift the furnace lid in addition to the above means. That is, the swivel floor 22 is set to the position A shown in FIG. Is performed by raising the furnace lid suspension chain 33. That is, the ring-shaped suspension 3 at the tip of the chain
1 is hooked on the holding link 32 of the furnace lid, and the furnace lid rises.

The mechanism for moving the furnace lid is shown in FIG. In the furnace lid swivel floor 28, the guide 25 and a part 38 of the rack 26 shown in FIG. 1 are separated from the other parts so that they move together with the turning of the furnace lid. Swing floor 28
Can be turned by the furnace lid turning means 40 along an imaginary concentric circle (not shown) centered on the axis 0 described above.
It has a structure that can be removed from 7.

Since the furnace lid turning means 40 is loaded on the tilting floor 10, the furnace body 1 must be held in a horizontal position when the furnace lid 2 is turned. This is because the furnace lid turning means 40 is fixed on the tilting floor 10, and the rail 41 is fixed on the floor of the building that does not tilt.

[0022]

According to the present invention, by using the above-described electrode swivel type furnace lid holding device, the upper electrode of the arc type electric furnace can be swung and moved without turning the furnace lid during energization. , Smooth operation became possible. In a three-phase post-AC arc type electric furnace, the relative angle between the two electrodes is 120 ° around the furnace axis, so if the electrodes are swung by 60 °, which is half that angle, the The position of the cold spot located in the middle is located in front of the electrode where the degree of heat transfer is larger, and it becomes possible to make the melting of the contents of the furnace uniform. Further, when the contents of the furnace are melted, if the swirl bed is appropriately reciprocated, a particularly hot or particularly cold place does not appear in the furnace body. In particular, on the side of the transformer (not shown) installation side (the side opposite to the dust collector duct) beside the slag door, it is not heated by the flow of exhaust air from the dust collector and is difficult to melt. As such, this location can be deliberately positioned so that the electrodes are closest to each other so that they are hot spots.

[Brief description of drawings]

FIG. 1 is a side view of an entire electric furnace to which the present invention has been applied.

FIG. 2 is a plan view of the entire electric furnace to which the present invention is applied.

FIG. 3 is an explanatory view of a furnace lid moving (turning) mechanism of the present invention.

FIG. 4 is a front view of an electric furnace to which the present invention has been applied.

FIG. 5 is a plan view of the entire electric furnace showing a position change of the furnace lid suspension chain.

FIG. 6 is a diagram showing an example of cold spot generation positions in a furnace.

[Explanation of symbols]

 1 Main Body 2 Furnace Lid 3 Opening 4 Electrode 7 Opening (Slag Outlet) 8 Opening (Steel Outlet) 9 Slag Door 10 Tilt Floor 11 Tilt Hydraulic Cylinder 12 Electrode Elevating Means 13 Winch 16 Elevating Part 19 Ring-shaped Fixed Part 22 Swivel floor 24 Wheels of swivel floor 25 Guide 26 Rack 27 Motor 28 Pinion 29 Electrode swivel means 30 Г type furnace lid holding beam 31 Ring-shaped hanger 32 Holding ring 33 Hanging chain 37 Furnace lid lifting means 38 Rack part 40 Furnace lid Turning means 41 Rail 43 Cylinder 47 Rail 48 Guide roll 50 Electrode holding means 52 Wheel 53 Wheel

Claims (4)

[Claims] 1. A capped electric furnace of an electrode swirl type provided on a tilting bed, wherein the swirl floor is on the tilting bed and moves reversibly on a concentric circle centered on the central axis of the furnace, and a lower end on the swirl floor. And a wheel that slides on a rail erected on the tilting floor is provided at the end of the horizontal portion of the Γ-shaped furnace lid holding beam. Electrode swirl type furnace lid holding device. 2. A furnace lid raising / lowering means fixed to the Γ-shaped furnace lid holding beam, a chain for hanging the furnace lid via a pulley by the furnace lid raising / lowering means, and a circular shape provided on the furnace lid at the tip of the chain. The furnace lid holding device for an electrode swirl type electric furnace according to claim 1, further comprising a slidable ring-shaped hanger that locks with the holding ring. 3. A wheel that slides on a concentric rail centered on the central axis of the furnace lid turning means is provided at the tip of the horizontal portion of the Γ-shaped furnace lid holding beam. 2. The electrode lid type furnace lid holding device described in 2. 4. A means for retracting a part of the rail according to claim 3 to a position where interference between the rail according to claim 3 and the Γ-shaped furnace lid holding beam can be avoided when the furnace body is tilted. The furnace lid holding device for an electrode swirl type electric furnace according to claim 3, wherein