KR960010600B1 - Muffle furnace - Google Patents

Abstract

No content.

Description

Vertical Muffle

1 is a longitudinal sectional view showing the structure of the lower part of a vertical muffle furnace;

2 is a horizontal cross-sectional view of the vertical muffle.

3 is a longitudinal sectional view showing an example in which the structure of the lower portion of the vertical muffle is different.

4 is a horizontal sectional view of the lower part of the muffle in the example of FIG.

FIG. 5 is the same view of FIG. 1 showing the structure of the lower part of the conventional vertical muffler. FIG.

* Explanation of symbols for main parts of the drawings

1,1f: body 2: body

3: opening 4: cap body

5,9: Outer jacket 6,10,20,63,64: Insulation

7,11: castable refractory material 8: heating means

12: heating gas chamber 15,15f: muffle

16,16f: atmosphere gas chamber 18: seal mechanism

19: outer cylinder 21: flange

22: inner cylinder 23: bottom plate

24: seal tank 25: low melting point metal

30,30f: inlet seal device 31: heat shield member

34: Communication Group 35: Communication Tube

39: wire 40: guide pipe of the outer ear 39

41: guide pulley 42: indicator

43: display plate 44, 50: weight

51,51f: workpiece 58,59,61: flange

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical muffle furnace which continuously heat-treats an object such as a metal strip in an atmosphere gas such as a reducing gas or an oxidizing gas.

As shown in FIG. 5, this type of vertical muffle furnace surrounds the cylindrical furnace body 1f arranged vertically and the workpiece 51f passed vertically through the furnace body 1f. The arranged medada is provided with the cylindrical muffle 15f of an expression type | mold, and the inlet sealing apparatus 30f (shown only a part in figure) connected to the lower end of the said muffle 15f. In such a vertical muffle, the to-be-processed object 51f can be heat-treated in the atmospheric gas suitable for the heat processing conditions in the atmospheric gas chamber 16f in the sealed muffle 15f.

In this type of vertical muffler, however, when the muffle 15f is used for a long time, permanent elongation occurs in the muffle 15f, and the lower portion of the muffle is gradually lowered as indicated by the arrow 54. If the permanent elongation is too large, the inlet seer 30f and another device installed below it interfere with each other, and the normal operation of the furnace cannot be continued. In (15f), the excess length dimension removal operation is performed as follows. That is, first, the vertical muffle is stopped. Next, the inlet seal device 30f is dismantled. Next, the muffle 15f is taken out from the side opening and closing in the furnace body 1f. From there, the middle part of the muffle 15f is cut off by the excess length and removed. Then, the lower end of the upper part and the upper part of the lower part are welded over the entire circumference to integrate both. Next, the mulle 15f is returned to the furnace body 1f again. Next, the seal device 30f is connected. The furnace will then resume operation.

However, in the removal work, it is necessary to cut the surface for welding at the lower end and the upper end prior to the welding, and to center the upper and lower parts properly at the time of welding. Their work is very cumbersome and laborious. In addition, since the work time is long, the time to restarting the furnace is long, and the economic loss due to the operation stop of the furnace is a big problem.

The present invention has been made in order to solve the problems (technical problems) of the prior art. When the permanent extension of the muffler exceeds the allowable value, the treatment for fixing the muffle to a predetermined length can be easily performed, and furthermore, the treatment thereof. It is an object of the present invention to provide a vertical muffle system which can reduce the economic loss caused by the oar suspension in the case of.

EMBODIMENT OF THE INVENTION Hereinafter, the figure which shows an Example of this application is demonstrated. In FIG. 1 and FIG. 2, the code | symbol 1 is a cylindrical furnace body arrange | positioned vertically, Comprising: The main body 2 and the lid | cover body 4 which open and close freely cover the opening part 3 of the side surface. The main body 2 is a well-known structure, 5 is a furnace shell formed from a metal material, 6 is a heat insulating material, and ceramic fiber is used, for example. 7 is a castable fireproof material. 8 is a burner illustrated as a heating means attached to the main body 2. The heating means may be an electrothermal heater. The lid 4 has the same structure, 9 is a furnace shell, 10 is a heat insulating material, and 11 is a castable fireproof material. 12 shows a heating gas chamber inside the furnace 1.

Next, 15 is a cylindrical muffle of a hanging type provided in the furnace body 1, for example, made of a heat-resistant metal such as Inconel. 16 indicates the gas chamber in the muffle.

Next, the seal mechanism 18 in the lower opening of the furnace 1 and the muffle 15 will be described. 19 is an outer cylinder arranged to surround the outer circumference of the lower part 15b of the muffle 15, and detachment is freely connected to the lower part of the furnace shell 5 by a bolt clamping the flange 21 integrally provided at the upper part. have. The height of this outer cylinder 19 is the permanent extension dimension of the muffle 15 by the time-use to the expansion and contraction dimensions of the muffle 15 due to the elevated temperature at the time of operation of the furnace (the dimension corresponding to the permanent extension dimension of the muffle 15). The outer cylinder 19 has its inner circumferential surface as an example of a heat insulating material 20, for example, a period in which cutting work is required as much as necessary, for example, while adding permanent elongation (dimensions) for one or two years. For example, the outer cylinder 19 can be formed of a material having relatively low heat resistance, and is formed of, for example, a stainless material, and 22 is coaxial with the outer cylinder 19 inside the lower muffle portion 15b. It is formed of a heat-resistant metal material such as, for example, Inconel 23 is a bottom plate connecting the lower portion of the outer cylinder 19 and the lower portion of the inner cylinder 22, the same material as the inner cylinder 22 24 is formed of the outer cylinder 19, the inner cylinder 22 and the bottom plate 23. The formed ring-shaped silt is shown, and the low melting point metal 25 is present therein. The low melting point metal is a solid at low temperature in non-operational furnace, and liquid at high temperature in operation. As an example, there is a lead bismuth alloy, the melting point is 70 DEG C. Since the lead bismuth alloy has a large specific gravity of 9.2, the pressure difference between the inside and the outside of the muffle 15 is It is difficult to produce a liquid level difference, and the alloy has a property of not having a wet property, so that the alloy does not survive in a state in which the alloy adheres to the inner wall surface of the seal tank. It is larger than the size of the permanent extension by use.

Therefore, even if the muffle 15 is stretched or permanently stretched, the lower end 15a is always immersed in the low melting point metal 25. 15a is the liquid level of the low melting point metal, and 26 and 27 are the heat insulating materials which floated on the liquid level, and it is used in order to prevent the low melting point metal 25 from exposing and exposing to the high temperature in a furnace. 28 is a heating wire additionally attached to the outer cylinder 19, and is for heating the low melting point metal 25 to make it a molten state. 29 is a heat insulating material which covered the outer side of the outer cylinder 19. As shown in FIG.

Next, 30 is a well-known inlet seal apparatus connected to the lower opening part of the muffle 15, and is connected to the lower part of the outer cylinder 19. As shown in FIG. 31 is a heat shield member integrally provided with this inside the inner cylinder 22, and is installed in order to prevent the high heat of the gas chamber 16 from reaching the inlet seal apparatus 30 and damaging it, for example, ceramic fiber, etc. It is formed of a material having a heat insulating property. 32 denotes a hole for processing a workpiece formed in the central portion of the heat shield member 31.

Next, the structure for liquid level management of the said low melting point metal 25 and management of the lower end position of the muffle 15 is demonstrated. 34 is a communication tank, and communicates with the seal tank 24 through the communication tube 35. The heating wire 28 and the heat insulating material 29 are also provided in the outer peripheral side of this communication tank 34 and the communication pipe 35, and the low melting point metal can be maintained in the molten state. 36 is a display device at the lower muffle position, and 37 is a liquid level display device. First, the muffle lower position display device 36 will be described. 38 is a buoy, and has a heat resistance that can withstand the elevated temperature of the low melting point metal 25 and a specific gravity smaller than that of the low melting point metal 25. For example, iron ingot is used. This buoy 38 abuts against the lower end 15a of the muffle 15 by buoyancy. 39 is a wire connecting one end to the buoy 38, and is used to transfer the vertical motion of the buoy 38 to the next indicator. For example, a stainless wire is used. 40 represents the guide pipe of the wire 39, 41 represents the guide pulley, respectively. 42 is an indicator, and consists of a display panel 43 displaying a scale and a weight 44 attached to the other end of the wire 39. In the muffle lower position display device 36, the weight 44 is located at a position corresponding to the lower end 15a of the muffle 15, and the position of the muffle lower end 15a is indicated by the weight 44. It is displayed on (43). Next, the liquid level position indicator 37 has the same structure, 45 is a buoy floated on the liquid level in the communication tank 34, 46 is a wire, 47 is a guide pulley, 48 is an indicator, and a display plate 49 and a weight It consists of 50. In this liquid level position display apparatus 37, the weight 50 is located at a position corresponding to the liquid level of the low melting point metal 25 in the seal tank 24, and the position of the liquid level is determined by the weight 50. It is displayed on (49).

In the above structure, as the burner 8 burns, the heating gas chamber 12 is heated to a high temperature, and the muffle 15 is heated by the high temperature heating gas. The atmosphere gas of the atmosphere gas chamber 16 is heated by the heat of the muffle 15. In this state, the strip-shaped to-be-processed object 51 enters into the heating gas chamber 16 from the to-be-processed object through-hole 32 through the inlet sealing apparatus 30, and moves it to a vertical state upwards as known. do. In the moving process, the workpiece 51 is heated. Atmospheric gas of the atmospheric gas chamber 16 during this operation is, for example, a mixed gas of nitrogen and hydrogen, the temperature of which is 1100 ° C, for example, and the pressure is 150 mmAq.

During operation of the furnace as described above, the lower end 15a of the muffle 15 is always immersed in the low melting point metal 25 in the molten state in the seal bath 24 regardless of the change in the length of the muffle 15. . Therefore, the cold outside air of the outside 52 of the furnace 1 enters the heating gas chamber 12, or enters the atmosphere gas chamber 16 to lower the temperature of these chambers, or partially cools the muffle 15 to cause distortion. Generation is prevented. Moreover, even between the heating gas chamber 12 and the atmospheric gas chamber 16, the gas of one chamber flows into the other chamber, and it is prevented from making the state of gas there.

At the start of the operation of the furnace, the low melting point metal 25 is melted by the heating wire 28 before the start of the elongation of the muffle 15. After the shrinkage of the muffle 15 is completed at the end of the operation, The low melting point metal 25 is solidified.

Next, the dimension of the permanent extension of the muffle 15 (e.g., about 10 mm per year per m of the muffle length, so if the length of the muffle 15 is, for example, 25 m, this dimension is, for example, one year). The treatment in the case where it becomes larger than about 250 mm) and exceeds the allowable value will be described. In the molten state of the low melting point metal 25, the bolt of the flange 21 is slowed and loosened by the connection of the furnace body 1 and the outer cylinder 19. FIG. In this state, the sealing mechanism 18 is farther away from the muffle 15. In the furnace body 1, the lid body 4 is opened. Then, the muffle 15 is taken out of the furnace body, and the lower end portion thereof is cut and removed by an excessive length, that is, a permanent extension corresponding dimension. Next, the cut muff 15 is returned to the main body 2 of the furnace again, and the lid 4 is closed. In addition, the said cutting removal operation may be performed with respect to the lower part of the muffle which the muffle 15 is exposed down from the lower opening part of the furnace body 1, while being suspended in the furnace body 1. As shown in FIG. Next, the seal mechanism 18 is raised to immerse the lower end 15a of the muffle 15 in the low melting point metal 25 and the flange 21 is connected to the furnace body 1. This completes the treatment.

Next, FIG. 3 and FIG. 4 showing still another embodiment of the present application will be described. In this example, the lower portion of the muffle has a structure having a plurality of connecting portions in advance, and the removal of a portion of the muffle is facilitated. In FIG. 3, the muffle 15e consists of two elements, the upper element 55 and the lower element 56. These elements are previously comprised separately, and are integrally connected by the connection part 57. As shown in FIG. The connection part 57 is an example of the connection structure which can be detachably attached, Comprising: The flange 58 attached to the lower end of the upper element 55, and the flange 59 attached to the upper end of the lower element 56, Both flanges (58, 59) are bolted to be in close contact with each other and detachable. 60 represents another connection part provided in the muffle. This connection part 60 is also an example of the connection structure which can be detachably attached, Comprising: The flange 61 mounted in the lower end of the lower element 56, and the flange 62 mounted in the inlet sealing apparatus 30e, Both flanges ( 61, 62 are bolted to each other and detachably bolted. The flange 58 and the flange 61 are formed in the same structure, the flange 59 and the flange 62 are formed in the same structure, and the flange 58 and the flange 62 are reconnection means. The muffle may be composed of three or more elements, and these may be connected to each other by the same connection structure as described above.

The lower and lower elements 56 of the upper element 55 are equipped with heat insulating materials 63 and 64, respectively. The outer circumferential surfaces of the heat insulating materials 63 and 64 and the flanges 58, 59 and 61 are located on the same circumference and are in sliding contact with the inner circumferential surface 65 at the charging opening of the heat insulating material 6e. The heat insulating material 63 mounted outward is buried between the plurality of reinforcing plates 66 extending radially from the lower part of the upper element 55, as shown in FIG. It is fixed to the 55 by the bolt 67. The heat insulating material 64 is also fixed to the lower element 56 in the same structure. In Fig. 3, reference numeral 68 denotes a seal roll in the inlet seal device 30e, and 69 denotes a heater provided in the heating gas chamber 12E in the furnace body 1e.

In the above structure, when the permanent extension of the muffle 15e exceeds the allowable value, the lower element 56 is removed as follows, and the muffle 15e is straightened to a predetermined length. That is, when the permanent elongation of the muffle 15e is accumulated and the lower end of the upper element 55 emerges below the furnace body 1e, for example, when it is lowered to the position of the lower end of the lower element 56 shown, the flange ( 61 and the flange 62 are separated, and the flange 58 and the flange 59 are separated, and the lower element 56 is removed. Then, the flange 58 and the flange 62 are reconnected to mount the inlet seal device 30e. In addition, the heat insulating material 31e is cut or replaced.

In addition, in the Example of FIG. 3, FIG. 4, the description which overlaps by attaching the letter e of the alphabet to the same code | symbol as the front figure was abbreviate | omitted in the part considered functionally equivalent or equivalent structure of the front figure.

As described above, in the present invention, when the target object 51 is heat treated, the target object 51 is passed through the sealed muffle 15, so that the target object 51 is an atmosphere gas suitable for the heat treatment conditions. There is an advantage that can be heat treated in.

Furthermore, even when the muffle 15 is used as described above, when the permanent extension of the muffle 15 increases due to long-term use and it exceeds the allowable value, the operation of shortening the muffle 15 to a predetermined length is relatively performed. In addition, there is an advantage that can be carried out in a short time. That is, in the present invention, after separating the muffle and the inlet seal device and removing a portion of the muffle and shortening it, the muffle and the inlet seal device can be reconnected in a very short time by using a reconnection means prepared in advance. There is an advantage. Since this fact is a furnace using muffle, even if it is inevitably necessary to make a short dimension up to the predetermined length, the operation is performed after stopping the operating time of the furnace for the operation, that is, The time required to bring the furnace back into operation can be shortened and the economic losses involved can be reduced.

Claims (4)

Arranged in the shape of a cylindrical furnace body arranged in a vertical shape, a suspending cylindrical muffle disposed in the furnace body so as to surround an object to be passed through the furnace body in a vertical state, and inside the inner cylinder of the lower portion of the muffle. A vertical muffle comprising: a heat shield member having a hole for passing a processed object, and an inlet seal device connected to a lower opening of the muffle to seal the inside and the outside of the muffle, wherein the muffle and the inlet seal device are provided. Is connected via a previously prepared reconnection means for reconnecting the remainder of the muffle and the inlet seal device when a portion of the muffle is removed, and the reconnection means corresponds to the diameter of the muffle mounted to the inlet seal device. And a ring-shaped sealing tank having a diameter and a low melting point metal retained in the sealing tank, and the lower end of the muffle is immersed in the low melting point metal. Vertical muffle. The vertical muffler according to claim 1, wherein the seal tank is further provided with a muffle lower position display device for indicating a position of a lower end of the muffle in the seal tank. The vertical muffler according to claim 1, wherein the seal tank is further provided with a liquid level position display device for indicating the position of the liquid level of the low melting point metal in the seal tank. Arranged in the shape of a cylindrical furnace body arranged in a vertical shape, a suspending cylindrical muffle disposed in the furnace body so as to surround an object to be passed through the furnace body in a vertical state, and inside the inner cylinder of the lower portion of the muffle. A vertical muffle comprising: a heat shield member having a hole for passing a processed object, and an inlet seal device connected to a lower opening of the muffle to seal the inside and the outside of the muffle, wherein the muffle and the inlet seal device are provided. Is connected through a reconnection means prepared in advance for reconnecting the remainder of the muffle and the inlet seal device when the part of the muffle is removed, and the muffle has a connection at two or more positions separated from each other up and down. The connection part consists of flanges that can be reconnected with the muffle of the upper part and the muffle of the lower part remaining when the muffles between the connecting parts are removed. And, a vertical-type muffle furnace, characterized in that for fastening the flange to the fixing means.