JPS631184Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a melting furnace having a nozzle for pouring molten metal at the bottom of the furnace, and particularly to a stopper device for opening and closing the nozzle.

BACKGROUND TECHNOLOGY Conventionally, bottom pouring type furnaces have been known as induction melting furnaces or heat retention furnaces, in which a nozzle is provided at the bottom of the furnace and the nozzle is opened and closed by a stopper rod inserted into the furnace from the furnace lid side. For example, it is shown in Japanese Patent Publication No. 51-11568 and Japanese Patent Application Laid-Open No. 58-12852.

This type of conventional bottom-pouring induction melting furnace generally has the configuration shown in FIG. That is, a furnace body 1 made of refractory material is supported by an outer frame 2 and is placed on a support stand 3 having an opening, and molten metal is poured into the center of the bottom of the furnace body 1. An induction coil 5 is provided on the outer periphery of the furnace body 1. A stopper rod 6 for opening and closing the nozzle 4 penetrates the center of an outer cover 7 installed to cover the upper opening of the furnace body 1 so as to be able to move up and down, and a stopper rod 6 is installed to maintain airtightness at the penetrating portion. The rod 6 and the outer cover 7 are in sliding contact. Further, above the stopper bar 6, an elevating mechanism 9 fixed to the frame 8 is arranged.
is composed of a drive device 10 and an elevating drive rod 11 that is moved up and down by the drive device 10, and the upper end of the stopper rod 6 is connected to the elevating drive rod 1.
1 via a pin 12.

Therefore, in the above-mentioned melting furnace, the metal in the furnace body 1 is inductively heated by energizing the induction coil 5, and the stopper rod 6 is pulled up by the lifting mechanism 9 to open the nozzle 4 to perform pouring. The hot water is stopped by abutting the stopper rod 6 against the open end of the nozzle 4 and closing the nozzle 4.

The problem that the device is trying to solve is that the stopper rod 6 is immersed in the molten metal, so it is made of refractory material. However, while the metal in the furnace is being melted, the stopper rod 6 is heated together with the metal in the furnace,
However, in the conventional melting furnace described above, although the stopper rod 6 and the lifting drive rod 11 are somewhat rotatable at the connection part by the pin 12, they are integrated in the axial direction, so that the stopper rod 6 is easily displaced by thermal expansion during melting.
Excessive compressive load (thermal stress) is applied to the
Therefore, if the nozzle 4, the stopper rod 6, and the lifting drive rod 11 are not aligned, the stopper rod 6 may buckle and, in extreme cases, may break. If the buckling deformation remains as plastic deformation,
When the stopper bar 6 is raised or lowered, excessive sliding occurs between the stopper bar 6 and the outer lid 4, which may cause the stopper bar 6 to break or buckle.
When the nozzle 4 is lowered to stop pouring, the tip of the stopper rod 6 does not exactly match the nozzle 4, resulting in incomplete molten metal cutting. Furthermore, the airtightness between the stopper rod 6 and the outer lid 7 is maintained by the sliding contact between them. If there is a misalignment between the axes of the stopper rod 6 and the outer lid 7, the stopper rod 6
As in the case where buckling deformation occurs, excessive sliding occurs when the stopper bar 6 is raised and lowered, causing problems such as breakage or buckling of the stopper bar 6.

In view of the above circumstances, the object of this invention is to provide a stopper mechanism for a bottom pouring melting furnace that can eliminate excessive compressive loads and sliding on the stopper rod.

Means to Solve the Problems In order to achieve the above purpose, this invention opens and closes a nozzle formed at the bottom of the furnace by raising and lowering a stopper rod immersed in the molten metal in the furnace using a lifting mechanism. In the bottom-pour melting furnace configured as above, the connecting rod connected to the upper end of the stopper rod is loosely fitted into a large diameter hole formed in the furnace lid, and one end is fixed to the open end of the large diameter hole, and the other end is fixed to the open end of the large diameter hole. The connecting rod is inserted through a flexible sleeve whose end is airtightly engaged with the connecting rod, and the connecting rod and the elevating mechanism are further connected by a telescoping mechanism. It is.

Embodiments Hereinafter, embodiments of this invention will be described with reference to FIGS. 1 to 3. In order to avoid duplication of explanation, parts of the configuration shown in FIG. 1 that are the same as those in FIG. 4 are given the same reference numerals as in FIG. 4, and the explanation thereof will be omitted.

In FIG. 1, an inner lid 13 is provided inside the furnace body 1, and the inner lid 13 is provided with a view hole 14 in the outer lid 7 so that the molten metal 15 can be observed or additives can be supplied thereto. A through hole 16 is formed. A stopper rod 6 for opening and closing the nozzle 4 is set to a length that projects slightly upward from the inner lid 13, and a connecting rod 17 is attached to the upper end of the stopper rod 6.
are connected via pins 18. Therefore, the connecting portion between the stopper rod 6 and the connecting rod 17 and the connecting rod 17 are protected by the inner cover 13 from thermal load due to thermal radiation from the molten metal 15. On the other hand, a large diameter hole 19 having a larger diameter than the connecting rod 17 is formed in the center of the outer cover 7, and the connecting rod 17 is loosely fitted into the large diameter hole 19 and passes through the outer cover. A flexible sleeve 20 seals between the connecting rod 17 and the outer cover 7. That is, the flexible sleeve 20 is made of a metal corrugated tube, and flanges 21 and 22 are attached to both ends as shown in FIGS. 1 and 2.
One flange 2 with the connecting rod 17 inserted
1 is fixed to the open end of the large diameter hole 19 in the outer cover 7 with a bolt 24 with a gasket 23 interposed therebetween. On the other hand, a support flange 25 is fitted into the part of the connecting rod 17 that protrudes above the outer lid 7 with a cap nut 26, and a gasket 27 made of fireproof cotton is filled between the two. and flexible sleeve 2
The upper flange 22 at 0 is the packing 28
The support flange 25 is fixed to the lower surface of the support flange 25 with the support flange 25 interposed therebetween. In addition, as shown in FIG. 2, the support flange 25 and the flange 2 fixed thereto
Through holes 29 and 30 whose axes coincide with each other are formed in the periphery of the bolt 24 that fixes the lower flange 21 of the flexible sleeve 20 to the outer cover 7. A portion 24a extends upward, and its shaft portion 24a is inserted into the through holes 29, 30. Therefore, the rear end shaft portion 2 of the bolt 24
4a serves as a guide to guide the support flange 25 up and down.

Further, the connecting rod 17 is connected to the elevating mechanism 9 via a telescoping mechanism 31. The telescopic mechanism 31 acts as a buffer against the stopper rod 6, and
It is constructed as shown in FIG. That is, a slide shaft 32 whose lower end is cylindrical is attached to the upper end of the connecting rod 17 via a pin 33, and the upper end of the slide shaft 32 is movable up and down into a cylindrical adjustment sleeve 34. The nut 3 screwed into the upper end of the slide shaft 32
5 prevents it from coming off from the adjustment sleeve 34. A spring holding plate 36 is disposed above the cylindrical portion of the slide shaft 32, and a spring receiving portion is formed at the lower end of the adjustment sleeve 34, and a compression spring 37 fitted onto the slide shaft 32 is attached to the spring holding plate 36. Spring holding plate 3
6 and the spring receiver.
Further, a threaded portion is formed on the outer circumferential surface of the adjustment sleeve 34, and the adjustment sleeve 34 is screwed into a bottomed cylindrical connection jig 38 via the threaded portion. A connecting jig 38 is connected to the lower end of the lifting drive rod 11 via a connecting screw 39. That is, in the telescopic mechanism 31, since the slide shaft 32 can move up and down with respect to the adjustment sleeve 34, such relative movement allows thermal expansion of the stopper rod 6 to prevent an increase in compressive load.
Further, the amount of compression of the compression spring 37, that is, the force of pushing down the stopper rod 6, is adjusted by changing the amount by which the adjustment sleeve 34 is screwed into the connection jig 38.

Note that the furnace body 1 is configured to be able to supply and discharge inert gas into the interior of the furnace body 1, and the drive device 10 in the lifting mechanism 9 is configured to be able to change the lifting speed of the stopper rod 6. Further, reference numeral 40 in FIG. 1 indicates an outer lid support arm.

When melting metal using the above-mentioned melting furnace, the lifting drive rod 11 in the lifting mechanism 9
by lowering the stopper rod 6 to the nozzle 4.
The nozzle 4 is closed by hitting the open end of the nozzle 4. In that case, the adjustment sleeve 34 in the telescoping mechanism 31
Since the stopper rod 6 can be lowered relative to the slide shaft 32, the elastic force of the compression spring 37 acts on the stopper rod 6 as a compressive force without applying any downward force from the elevating mechanism 9. When the inside of the furnace is heated by induction in such a state, the temperature of the stopper rod 6 increases as the metal melts, but the temperature of the stopper rod 6 increases.
Since the slide shaft 32, which is integrated with the slide shaft 32, can rise relative to the adjusting sleeve 34, which is the fixed side, the stopper rod 6 thermally expands while compressing the compression spring 37, and the axis line An increase in compressive force in the direction is prevented.

In addition, tapping and stopping of the melt in the above melting furnace is performed by raising and lowering the stopper rod 6 using the elevating mechanism 9 to open and close the nozzle 4. 7 and is held via the flexible sleeve 20, the connecting rod 17 is allowed to move in the radial direction. Even if there is a misalignment of the axis, no unreasonable sliding will occur during lifting and lowering, and dangers such as breakage and buckling can be avoided. In addition, when stopping the melt by lowering the stopper rod 6, in the above melting furnace, the stopper rod 6 is integrated with the connecting rod 17 and can move somewhat in the radial direction, and the stopper rod 6 is moved by the compression spring 3.
Since it is configured to press downward with an elastic force of 7,
The tip of the stopper rod 6 fits easily into the upper end opening of the nozzle 4, and as a result, the hot water can be stopped reliably and easily.

Further, when setting the stopper rod 6 to the furnace body 1, the stopper rod 6 and the connecting rod 17 are set on the furnace body 1.
The connecting rod 17 is inserted into the large diameter hole 19 and the flexible sleeve 20 while the outer cover 7 is placed over the furnace body 1. In this case, the connecting rod 17 and the large diameter hole 19 and Since the flexible sleeve 20 is loosely fitted, no load is applied to the connecting rod 17, and therefore the stopper rod 6 and the outer cover 7 can be easily set without causing accidents such as breakage of the connecting rod 17. can do.

Note that the expansion/contraction mechanism in this invention is not limited to the configuration shown in the above embodiment, but the point is that the stopper rod or the connecting rod attached to it is connected to the lifting mechanism in a state that allows the stopper rod to expand and contract. Any configuration that connects them is sufficient.

Here, the results of tests conducted by the present inventors using an actual machine show that the connecting rod, which is integrated with the stopper rod, is loosely fitted into the outer cover, which makes it difficult to
Setting up the stopper rod and furnace lid before melting work, which used to take about 60 minutes, can now be done in about 10 minutes. In addition, problems with stopper rods during melting work have conventionally been reported with a breakage rate of 30% and a buckling rate of 10%.
However, with the configuration of the present invention, there were no troubles due to breakage or buckling. During the melting process, compression of the spring of the expansion mechanism was observed due to thermal expansion of the stopper rod.

Effects of the invention As is clear from the above explanation, in the stopper device of this invention, the connecting rod, which is integrated with the stopper rod that directly opens and closes the nozzle, is loosely fitted into the large diameter hole formed in the outer cover, and the stopper device is flexible. Since the space between the stopper rod and the outer lid is sealed by the flexible sleeve, and the connecting rod is connected to the lifting mechanism via the expansion and contraction mechanism, thermal expansion and radial deflection of the stopper rod can be tolerated. Excessive axial compressive force is not applied to the stopper rod during heating and melting of metal in the furnace, and no unreasonable sliding occurs when the stopper rod is raised and lowered, so the stopper rod and the connecting rod integrated with it are Breakage and buckling can be reliably prevented. In addition, with this invention, the stopper rod can swing in the radial direction, so even if the axes of the nozzle and the stopper rod are slightly misaligned, the stopper rod can be moved by the guide function of the taper at the nozzle opening end and the taper at the tip of the stopper rod. To securely fit a rod into an open end of a nozzle and to stop hot water without causing problems such as insufficient hot water running out.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of this invention, Fig. 2 is a detailed view of the flexible sleeve, Fig. 3 is a detailed view of the expansion mechanism, and Fig. 4 is a conventional induction melting furnace. It is a schematic sectional view. DESCRIPTION OF SYMBOLS 1... Furnace body, 4... Nozzle, 6... Stopper rod, 7... Outer lid, 9... Lifting mechanism, 17... Connecting rod, 19... Large diameter hole, 20... Flexible sleeve,
31... Telescopic mechanism.

Claims (1)

[Scope of utility model registration request] In a bottom pouring melting furnace configured to open and close a nozzle formed at the bottom of the furnace by raising and lowering a stopper rod immersed in the molten metal in the furnace using an elevating mechanism, a connection connected to the upper end of the stopper rod 6 is used. The rod 17 is loosely fitted into a large-diameter hole 19 formed in the furnace lid 7, and one end is fixed to the open end of the large-diameter hole 19, and the other end is engaged with the connecting rod 17 while maintaining an airtight state. A stopper device for a bottom pouring melting furnace, characterized in that the connecting rod 17 is inserted through the flexible sleeve 20, and the connecting rod 17 and the elevating mechanism 9 are connected by a telescoping mechanism 31. .