JP2014126215A - Dust collecting device of electric furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dust collecting device of an electric furnace which exhibits excellent dust collecting performance in both a state that a furnace cover does not cover an opening of the electric furnace and a state that the cover covers the opening.SOLUTION: An air blow-out nozzle 20 and an air suction nozzle 10 are arranged at positions which sandwich an opening 2A of an electric furnace 2, and air sucked from the suction nozzle 10 is sent to a dust collector 50 through a first passage 81. Furthermore, a second passage 82 for making the blow-out nozzle 20 and the first passage 81 communicate with each other is arranged, and air switching means 40 for switching a flow direction of air to a forward direction or a reverse direction is arranged in the second passage 82. Then, in a state that a furnace cover 3 does not cover the opening 2A, air in the second passage 82 flows to the forward direction, is made to blow out of the blow-out nozzle 20, and sucked from the suction nozzle 10, and on the other hand, in a state that the furnace cover 3 covers the opening 2A, the air in the second passage 82 flows to the reverse direction, and sucked from the blow-out nozzle 20.

Description

  The present invention relates to a dust collector for an electric furnace that collects dust such as fumes and gas soot of the electric furnace.

  As a dust collector for this type of electric furnace, for example, a ring hood is provided around the opening of an electric furnace having a furnace lid, and the ring hood is connected to a dust collector, or the center of an improved ring hood is provided. There is a configuration in which the opening is made large so that the furnace lid can enter from above the ring hood and reach the opening of the electric furnace, and the opening of the electric furnace can be directly closed by the furnace lid ( For example, see Patent Document 1.) In addition, as a dust collector for an electric furnace without such a ring hood, for example, a push hood and a pull hood provided so as to face each other with the opening of the furnace body interposed therebetween, or an improved furnace body There is a type in which a tilting floor in the upper part is provided with a push hood and a pull hood that rotate together with the tilting floor and perform suction action at the time of tapping so as to face each other across the opening of the furnace body (for example, Patent Document 2). reference.).

  However, the former dust collector of the former with the ring hood is difficult to collect dust in the opening, particularly in the vicinity of the center, when the furnace lid is removed from the opening of the electric furnace, such as when tapping. I have a problem. In addition, the rising speed of the fume in the opening is, for example, 2 to 4 m / s. On the other hand, the dust collector of the electric furnace with the latter push hood and pull hood is designed in consideration of dust collection at the time of tapping, but about dust collection in a state where the furnace lid covers the opening of the electric furnace. Not enough consideration. In addition, any dust collector has a problem that when the diameter of the opening of the electric furnace is large, dust collection is insufficient when the furnace lid is removed from the opening of the electric furnace. .

JP 2003-322475 A Japanese Utility Model Publication No. 5-3900

  The main problem to be solved by the present invention is that it exhibits excellent dust collection ability in both the state where the furnace cover does not cover the opening of the electric furnace and the state where the furnace cover covers the opening of the electric furnace. An object of the present invention is to provide a dust collector for an electric furnace. It is also desirable to provide an electric furnace dust collector that exhibits excellent dust collection capability even when the diameter of the opening of the electric furnace is large.

The present invention that has solved this problem is as follows.
[Invention of Claim 1]
An air blowing nozzle and an air suction nozzle are provided at a position sandwiching the opening of the electric furnace having the furnace lid, and the air sucked from the suction nozzle is sent to the dust collector through the first flow path. A dust collector for an electric furnace,
A second flow path that communicates the blowing nozzle and the first flow path;
In the second flow path, the air flow direction in the second flow path is changed from the first flow path side to the blowing nozzle side (forward direction), or from the blowing nozzle side to the first flow path. Air switching means for switching to the flow path side (reverse direction),
In the state where the furnace lid does not cover the opening of the electric furnace, the air in the second flow path flows in the forward direction and is blown out from the blowing nozzle and sucked into the suction nozzle,
On the other hand, in a state where the furnace cover covers the opening of the electric furnace, the air in the second flow path flows in the reverse direction and the air is sucked from the blowing nozzle. Yes,
A dust collector for an electric furnace.

[Invention of Claim 2]
The suction nozzle extends in an arc around the opening of the electric furnace,
On the suction nozzle, there are mounted a plurality of rotating plates that become narrower from the base end portion toward the tip end portion and rotate about the base end portion. The rotating plate is rotated until the base end of the rotating nozzle is continuous with the spreading direction of the suction nozzle and the side edges of the rotating plates adjacent to each other are in contact with each other above the opening of the electric furnace. ing,
The dust collector for an electric furnace according to claim 1.

  According to the present invention, the dust collection of an electric furnace that exhibits excellent dust collection capability in both the state where the furnace lid does not cover the opening of the electric furnace and the state where the furnace lid covers the opening of the electric furnace. It becomes a device.

It is a flowchart of the dust collector of the electric furnace which concerns on this form. It is a cross-sectional schematic diagram which shows the dust collection mechanism of an electric furnace upper part. It is a plane schematic diagram which shows the dust collection mechanism of an electric furnace upper part. It is a plane conceptual diagram of an air switching machine.

Next, an embodiment of the present invention will be described.
As shown in FIG. 1, a dust collector 1 for an electric furnace according to this embodiment is intended to collect dust such as fumes and gas smoke generated from an electric furnace 2 having a furnace lid 3 (see FIG. 2). Device. Examples of the electric furnace 2 include a low-frequency induction furnace and a high-frequency induction furnace that melt metals such as various alloys and cast iron at a high temperature. The furnace lid 3 opens and closes the opening 2A of the electric furnace 2, and is normally movable. For example, when the furnace cover 3 is turned and lifted, the furnace cover 3 does not cover the opening 2A, that is, the opening 2A is opened, while the furnace cover 3 is placed on the electric furnace 2. Then, the furnace lid 3 covers the opening 2A, that is, the opening 2A is closed. The opening / closing operation of the furnace lid 3 can also be performed using a known means such as an air cylinder.

The state of generation of dust such as fumes and gas smoke from the electric furnace 2 is as follows.
That is, in the electric furnace 2, the furnace lid 3 is not in a state of covering the opening 2A, and when high-temperature molten metal is exposed to the outside air, oxidation starts on the surface of hot water (molten metal), and fumes, gas smoke, etc. Dust is generated. The dust is in the form of fine particles having a diameter of about 0.1 to 3.0 μm and is estimated to be a high temperature of about 250 to 400 ° C. The air in the opening 2A of the electric furnace 2 is heated by contact with the molten metal and diffuses upward by a strong buoyancy increasing force. Accordingly, dust is also diffused upward by the buoyancy increasing force. In addition, when the electric furnace 2 is tilted and molten metal is poured into a ladle or the like, a large amount of dust is generated from the hot water surface or the ladle.

  On the other hand, in the electric furnace 2, dust such as fumes is generated immediately after energization after the melt is put into the electric furnace 2 and the opening 2A is covered with the furnace lid 3. Even if the dust such as fumes covers the opening 2 </ b> A with the furnace lid 3, there is a possibility that the dust may leak from the gap between the electric furnace 2 and the furnace lid 3. As described above, dust such as fume may be generated and diffused in both the state where the furnace cover 3 does not cover the opening 2A and the state where the furnace cover 3 covers the opening 2A. Is a dust collector 1 for an electric furnace according to the present embodiment. Details will be described below.

  As shown in FIG. 1, the dust collector 1 for an electric furnace according to the present embodiment is provided with an air blowing nozzle 20 and an air suction nozzle 10 at, for example, opposing positions across the opening 2A of the electric furnace 2. It has been. The air sucked from the suction nozzle 10 is sent to the dust collector 50 through the first flow path 81.

  The first flow path 81 is sufficient if it can flow air containing dust such as fume to the dust collector 50. However, since dust such as fume is usually at a high temperature, it is preferably constituted by, for example, a ceramic or metal pipe, a duct, or the like.

  The dust collector 50 collects dust such as fume contained in the air, and its specific structure is not particularly limited, and a known dust collector can be used. In the illustrated example, a dust collector 50 provided with a filter 51 such as a bagg filter is used. In the dust collector 50, dust such as fume that does not pass through the filter 51 stays at the bottom 52 of the dust collector 50 having an inverted conical shape, and is appropriately discharged to the outside through the rotary valve 53. On the other hand, the air passing through the filter 51 passes through the duct 61 and is discharged into the atmosphere from a discharge pipe (not shown) provided with the silencer 62. In this embodiment, a suction fan 63 is provided at the front end of the duct 61, and air is sucked from the suction nozzle 10 via the duct 61, the dust collector 50, and the first flow path 81, and the suction force is increased. It can be adjusted.

  On the other hand, in the dust collector 1 of this form, the 2nd flow path 82 which connects the blowing nozzle 20 and the 1st flow path 81, for example, the intermediate part is provided. The second flow path 82 only needs to be able to flow air, and may be configured by, for example, a ceramic or metal pipe, a duct, or the like.

Further, in the second flow path 82, the air flow direction in the second flow path 82 is changed from the first flow path 81 side to the blow nozzle 20 side (forward direction), or the blow nozzle 20. Air switching means 40 for switching from the side to the first flow path 81 side (reverse direction) is provided. The purpose of switching the air flow direction by the air switching means 40 is as follows.
First, in a state where the furnace lid 3 does not cover the opening 2A, the air in the second flow path 82 is caused to flow in the forward direction using the air switching means 40. As a result, air is blown out from the blowing nozzle 20, and this air is sucked from the suction nozzle 10. Therefore, the upward airflow due to the above-described buoyancy increasing force changes to a horizontal airflow above the opening 2A, and as a result, dust such as fume is sucked from the suction nozzle 10. And since the suction | attraction of this dust is performed using a horizontal airflow, unlike the case where a ring hood is utilized, the dust collection of the central part vicinity of 2 A of opening parts is also enough.

In this respect, since the kinetic energy of the air flow is air volume × (wind speed) ² , the dust collection performance (dust collection force) of dust such as fume is, for example, the opening area of the blow nozzle 20 or the suction nozzle 10 or the second area. It can be adjusted by appropriately designing the wind speed of the air flowing in the flow path 82.

  Next, in a state where the furnace cover 3 covers the opening 2A, the air in the second flow path 82 is caused to flow in the reverse direction using the air switching means 40. As a result, air is sucked from the suction nozzle 10 and air is also sucked from the blowing nozzle 20. Therefore, dust such as fumes leaking from the gap between the electric furnace 2 and the furnace lid 3 is collected over a wide range, and the dust collection performance is improved. As a result, according to the dust collector 1 according to the present embodiment, the furnace lid 3 does not cover the opening 2 </ b> A of the electric furnace 2 or the furnace cover 3 covers the opening 2 </ b> A of the electric furnace 2. Exhibits excellent dust collection ability.

Here, the specific structure and the like of the air switching means 40 are not particularly limited as long as the direction in which the air flows can be switched. However, the air switching means 40 of this embodiment is recommended in that it can be provided inexpensively and easily.
That is, as shown in FIG. 4, the air switching unit 40 according to the present embodiment mainly includes a four-way (mouth) damper 41, a fan 42, and a third flow path 43. The four-way damper 41 has four openings 41A, 41B, 41C, and 41D, the second flow path 82 is connected to the opposed openings 41A and 41B, and the third openings 41C and 41D are opposed to each other. Both ends of the flow path 43 are connected. Furthermore, the four-way damper 41 is provided with a switching blade 44 that can rotate around the rotation shaft 45. By rotating the switching blade 44, the opening 41A and the opening 41D communicate with each other, the opening 41B and the opening 41C communicate with each other, and the opening 41A and the opening 41D and the opening 41B and the opening 41C do not communicate with each other (in the illustrated example). The switching blade 44 in this state is indicated by a solid line.Hereinafter, this state is referred to as a “forward state”), or the opening 41A and the opening 41C communicate with each other, the opening 41B and the opening 41D communicate with each other, and the opening 41A and The state where the opening 41C and the opening 41B and the opening 41D do not communicate with each other (in the illustrated example, the switching blade 44 in this state is indicated by a two-dot broken line. Hereinafter, this state is referred to as a “reverse state”).

  Moreover, the fan 42 is interposed in the middle of the 3rd flow path 43 comprised, for example by a pipe line, a duct, etc., and the air in the 3rd flow path 43 is made to the opening 41C side from the opening 41D side. It can flow.

  According to the air switching means 40 of the present embodiment described above, air flows as follows. First, when the switching blade 44 is rotated to the “forward state”, the air in the second flow path 82 flows from the first flow path 81 toward the damper 41 and flows into the damper 41 from the opening 41A. . The air that has flowed into the damper 41 flows out of the opening 41D, flows in the third flow path 43 toward the opening 41C while being accelerated by the fan 42, and flows into the damper 41 again from the opening 41C. . The air that has flowed into the damper 41 flows out of the opening 41 </ b> B and flows in the second flow path 82 toward the blowing nozzle 20.

  On the other hand, when the switching blade 44 is in the “reverse state”, the air in the second flow path 82 flows from the blow nozzle 20 side toward the damper 41 and flows into the damper 41 from the opening 41B. The air that has flowed into the damper 41 flows out of the opening 41D, flows in the third flow path 43 toward the opening 41C while being accelerated by the fan 42, and flows into the damper 41 again from the opening 41C. . The air that has flowed into the damper 41 flows out of the opening 41 </ b> A and flows in the second flow path 82 toward the first flow path 81.

By the way, the dust collector 1 of the electric furnace according to the present embodiment has been devised in various ways as described below so that it can exhibit an excellent dust collecting ability even when the diameter of the opening 2A of the electric furnace 2 is large. ing.
That is, first, as shown in FIG. 2, the suction nozzle 10 of this embodiment has a suction port 10A formed on the end surface on the opening 2A side, and as shown in FIG. 3, around the opening 2A. The shape is a circular arc. According to this configuration, even when dust such as fume carried by the horizontal airflow flows from the blow nozzle 20 side to the suction nozzle 10 side, even if the dust spreads in the circumferential direction of the opening 2A, the suction nozzle 10 (suction port 10A). ).

  In particular, in the present embodiment, from the viewpoint of suppressing the spread of dust such as fumes in the circumferential direction, the blowing nozzle 20 is also formed in a shape that extends in an arc around the opening 2A.

  Here, the range in which the suction nozzle 10 and the blowout nozzle 20 spread in an arc shape is not particularly limited. However, in this embodiment, the suction nozzle 10 has a shape that expands in a range of 180 °, and the blowout nozzle 20 includes two symmetrically across the center line L from the blowout nozzle 20 toward the suction nozzle 10, Both ends of the two blow nozzles 20 and 20 have a shape that widens in a range of 180 °. According to this form, the above effect, that is, even if dust such as fume spreads in the circumferential direction can be reliably sucked, the spread itself in the circumferential direction of the dust such as fume can be suppressed, In addition, the range of collecting dust such as fumes leaking from the gap between the electric furnace 2 and the furnace cover 3 in a state where the furnace cover 3 covers the opening 2A is expanded. Dust collection performance is also improved.

  On the other hand, the dust collector 1 of the electron furnace according to the present embodiment is narrower on the top plate 11 constituting the top surface of the suction nozzle 10 and becomes narrower from the base end portion 31 toward the tip end portion 32 in the illustrated example. A plurality of rotating plates 30 having a shape are mounted, five in the illustrated example. The plurality of rotating plates 30, 30... Are configured to rotate about a rotating shaft 31 </ b> A provided in the base end portion 31.

  The plurality of rotating plates 30, 30... Are first placed so that the base end portions 31 (rotating shafts 31 </ b> A) of the respective rotating plates 30 are connected in the spreading direction of the suction nozzle 10. ing. In addition, the mounting is performed so that the rotating plates 30, 30... Rotate until the side edges 31, 31 of the adjacent rotating plates 30 abut each other above the opening 2A. . The state in which the side edges 31 of the rotating plates 30 adjacent to each other are in contact with each other is referred to as “standing state”. In this regard, the diameter of the opening 2A of the electric furnace 2 may be, for example, a large diameter of 0.5 to 1.5 m. In the case of such a large diameter, the horizontal air flow is sucked. It becomes easy to go around the nozzle 10 (above the top plate 11). However, according to this embodiment, as shown in FIGS. 2 and 3, the plurality of rotating plates 30, 30... Prevent the horizontal air current from flowing around the suction nozzle 10. Since it is reliably sucked, dust such as fumes is also reliably guided to the suction nozzle 10 and dust collection performance is improved. Further, since the movable plate 30 can be rotated on the rotation shaft 31A and stacked on the top plate 11 of the suction nozzle 10 (in a prone state), the furnace lid 3 is mounted on the electric furnace 2. There is no possibility that the rotating plate 30 becomes an obstacle in placing.

  In this embodiment, how the rotating plate 30 is rotated is not particularly limited, and for example, the rotating plate 30 can be rotated using an air cylinder or the like (not shown). Further, the material of the rotating plate 30 is not particularly limited, but is preferably formed of, for example, ceramics or metal so that it can withstand high temperatures.

[Others]
The electric furnace dust collector 1 of the present embodiment is not limited to the case where the number of electric furnaces 2 to be collected is one, for example, two, three, four, or more. It can also be used when When there are a plurality of electric furnaces 2, the nozzles 10, 20, the second flow path 82, the air switching machine 40 and the like are provided for each electric furnace. In the example shown in FIG. 1, the air sucked from the suction nozzle 10X provided in another electric furnace is configured to communicate with the middle of the first flow path 81 through the flow path 81A.

  On the other hand, in the dust collector 1 of the electric furnace of this embodiment, in the state where the furnace lid 3 does not cover the opening 2A, it is necessary to increase the amount of suction from the suction nozzle 10 in order to generate the horizontal airflow. There is. On the other hand, in the state where the furnace cover 3 covers the opening 2A, only the dust such as fumes leaking from the gap between the electric furnace 2 and the furnace cover 3 is sucked, so the suction amount from the suction nozzle 10 is reduced. be able to. Therefore, a signal (open / close signal) indicating the open / closed state of the furnace lid 3 is transmitted to the air volume adjusting damper 7 provided in the middle of the flow paths 81 and 81A connected to the suction nozzles 10 and 10X. By changing the flow rate, the flow rate of the air flowing through the flow paths 81 and 81A is controlled to control the suction amount from the suction nozzles 10 and 10X.

  In the present embodiment, a signal (opening signal) indicating the opening degree of each of the air volume adjusting dampers 7 and 7 is transmitted to the inverter 64, and the driving force of the suction fan 63 is controlled by the inverter 64, thereby The total flow rate of the air flowing through the flow paths 81 and 81A can be controlled.

  INDUSTRIAL APPLICABILITY The present invention is applicable as a dust collector for an electric furnace that collects dust such as fumes and gas soot of an electric furnace.

  DESCRIPTION OF SYMBOLS 1 ... Dust collector, 2 ... Electric furnace, 2A ... Opening part, 3 ... Furnace lid, 10 ... Suction nozzle, 20 ... Blowing nozzle, 30 ... Turning plate, 40 ... Air switching machine, 41 ... Four-way damper, 41A, 41B, 41C, 41D ... opening, 42 ... fan, 43 ... third flow path, 50 ... dust collector, 51 ... filter, 53 ... rotary valve, 61 ... duct, 62 ... silencer, 63 ... suction fan, 81 ... first , 82... Second channel.

Claims (2)

An air blowing nozzle and an air suction nozzle are provided at a position sandwiching the opening of the electric furnace having the furnace lid, and the air sucked from the suction nozzle is sent to the dust collector through the first flow path. A dust collector for an electric furnace,
A second flow path that communicates the blowing nozzle and the first flow path;
In the second flow path, the air flow direction in the second flow path is changed from the first flow path side to the blowing nozzle side (forward direction), or from the blowing nozzle side to the first flow path. Air switching means for switching to the flow path side (reverse direction),
In the state where the furnace lid does not cover the opening of the electric furnace, the air in the second flow path flows in the forward direction and is blown out from the blowing nozzle and sucked into the suction nozzle,
On the other hand, in a state where the furnace cover covers the opening of the electric furnace, the air in the second flow path flows in the reverse direction and the air is sucked from the blowing nozzle. Yes,
A dust collector for an electric furnace. The suction nozzle extends in an arc around the opening of the electric furnace,
On the suction nozzle, there are mounted a plurality of rotating plates that become narrower from the base end portion toward the tip end portion and rotate about the base end portion. The rotating plate is rotated until the base end of the rotating nozzle is continuous with the spreading direction of the suction nozzle and the side edges of the rotating plates adjacent to each other are in contact with each other above the opening of the electric furnace. ing,
The dust collector for an electric furnace according to claim 1.

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