JP2008002747A - Atmospheric gas sealing method and device for heating furnace, and heating furnace comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device for sealing an atmospheric gas of a heating furnace, and the heating furnace comprising the device. <P>SOLUTION: This atmospheric gas sealing method comprises connecting gas tanks 4a, 4b of which an upper part is defined by a partitioning portion 1 and a lower part is communicated to be composed of an upstream-side chamber 2 and a downstream-side chamber 3, to carry-in passage 6 or a carry-out passage 11 to a heating furnace 5, supplying a sealing gas heavier than a furnace atmospheric gas and further heavier than the outside air to the upstream-side chamber and the downstream-side chamber in a state that a top face of the sealing gas is constantly positioned higher than a lower end of the partitioning portion, allowing a heated object 8 to enter into the downstream-side chamber from the upstream-side chamber through a lower side with respect to a lower end of the partitioning portion, and then to pass through the sealing gas tank to be carried into the furnace from the carrying-in passage, and further allowing the heated object 8 after the heating treatment similarly to pass through the sealing gas tank through the carry-out passage 11 to be carried out to the outside of the furnace. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method and apparatus for sealing an atmosphere gas in a heating furnace in which a metal product, particularly a metal product containing a hardly reduced metal material, is subjected to heat treatment such as continuous sintering and brazing, and heating provided with the device. It relates to the furnace.

  In the text, the base end side is expressed as the upstream side (or the carry-in side) and the front end side is expressed as the downstream side (or the carry-out side) in the moving direction of the product to be heated (product).

When heat-treating a metal product such as stainless steel, it is widely known to perform the product in a reducing atmosphere without oxidizing the product. For this reason, a heating furnace using hydrogen (H ₂ ) gas, which is a reducing gas, as an atmosphere is frequently used. In this type of heating furnace, hydrogen gas as an atmosphere is very light compared to air, and various measures have been applied to the structure of the heating furnace in order to prevent explosion due to intrusion of air.

  For example, a tunnel-type carry-in device that is inclined so as to gradually increase toward the heating furnace on the carry-in side of the heating furnace, and a tunnel-type carry-in device that is inclined so as to gradually become lower as the distance from the heating furnace is increased. A so-called hump type in which carry-out devices are connected in series and the carry-in device and the carry-out device are filled with an inert gas such as nitrogen gas so that hydrogen gas in the heating furnace is gas-sealed. Heating furnaces are known.

  However, in this hump-type heating furnace, the article to be heat-treated (product) goes up the inclined surface and is inserted into the furnace, and the heat-treated article to be heat-treated is carried down the slope to the outside. When the product to be heated has an unstable shape or length, there is a problem that the inclined surface is likely to fall, slip, etc., and the processing becomes difficult or impossible. There is also a drawback that the entire apparatus is inevitably long in order to ensure the gradient of the apparatus and the carry-out apparatus.

  In addition, a horizontal structure in which the carry-in device and the carry-out device before and after the heating furnace are set to the same height as the heating furnace without being inclined as described above has been proposed. The structural heating furnace needs to be constantly replenished with hydrogen gas that has leaked out of the furnace structurally, and the amount of hydrogen gas used increases, and as a safety measure for leaking hydrogen gas, Since the frame curtain is provided at the doorway and a means for burning the leaked hydrogen gas is employed, the problem that the product to be heated (product) is easily affected by the heat of the burner or the like that forms the frame curtain, and There has been a problem that moisture generated by combustion adheres to the conveyor belt and is carried into the furnace to raise the dew point in the furnace.

  The present invention provides a novel atmosphere gas sealing method for a heating furnace, a sealing apparatus for the same, and a heating furnace equipped with the apparatus that can solve the above-described problems all at once.

  In order to achieve the above object, an atmosphere gas sealing method for a heating furnace according to the present invention is a sealing gas tank composed of an upstream chamber and a downstream chamber that are partitioned by a partitioning portion and communicated with a lower portion. The sealing gas is heavier than the atmosphere gas of the heating furnace in the sealing gas, and the upper surface of the sealing gas is always lower than the lower end of the partition. After supplying the heat-treated product from the upstream side chamber through the lower side from the lower end of the partition and entering the downstream side chamber, after passing through the sealing gas tank, It was carried into the furnace from the carry-in passage, and the heat-treated product after the heat treatment was taken out of the furnace after passing the inside of the gas tank for sealing through the carry-out passage in the same manner as described above. Features.

  The atmosphere gas sealing device for a heating furnace and the heating furnace provided with the apparatus according to the present invention are a sealed structure composed of an upstream chamber and a downstream chamber that are partitioned by a partitioning portion and communicated with the lower portion. The gas tank for stopping is connected to the carry-in passage or the carry-out passage to the heating furnace, and the product to be heated is first passed from the upstream chamber to the lower chamber through the lower end of the partition part and sealed. After passing through the gas tank, carry it into the furnace through the carry-in passage, or pass the heat-treated product after heat treatment in the heating furnace through the carry-out passage in the same manner as above. And a device for transporting the heat-treated product to be carried out of the furnace and then sealed in the sealing gas tank heavier than the furnace atmosphere gas or heavier than the furnace atmosphere gas and heavier than the outside air. The upper surface of the sealing gas is lower than the lower end of the partition. The atmospheric gas in the heating furnace housed in a state in which the upper side, characterized in that it is configured to seal.

In this heating furnace, the atmosphere gas sealing device described above is arranged on both the carry-in side and the carry-out side of the heating furnace, and the gas tanks for sealing in both the atmosphere gas sealing devices are connected by a communication pipe line. By connecting, the sealing gas in both tanks is brought into communication, or the sealing gas used is Ar gas or CO ₂ , and this Ar gas or CO ₂ is heavier than the atmosphere gas in the furnace and You may make it cool so that it may be heavier than outside air (namely, a density is made high).

  According to the present invention, the atmospheric gas in the heating furnace is sealed by the sealing gas heavier (that is, higher in density) than the furnace atmospheric gas accommodated in the sealing gas tank and heavier than the outside air. Therefore, the atmospheric gas in the furnace is unlikely to leak out of the heating furnace, and the external air is less likely to enter the sealing gas tank or to be diffused into the atmosphere. The amount of replenishment (use) can be reduced, it can be carried out without providing a frame curtain using a burner, etc., not only can the energy required for combustion of the burner etc. be saved, but also the influence of heat from the combustion The problem of receiving heat-treated products (products) can also be solved.

  In addition, since the heat-treated product (product) is passed through the sealing gas tank and sent into the furnace, oxygen and oil adhering to the heat-treated product (product) are removed from the heating furnace. There is a secondary effect such as pre-cleaning before moving to.

  Furthermore, since this sealing gas tank is provided below the moving floor of the heating furnace, it is advantageous when a plurality of heating furnaces are used in a horizontal arrangement, for example, as shown in FIG.

  In addition, since there is no need to provide an inclined moving part in the apparatus for transferring the heat-treated product into or out of the furnace, the entire apparatus can be downsized, and the heat-treated product is unstable or long. It is possible to avoid such a problem that the processing when it is a thing becomes difficult or impossible.

  FIG. 1 is a schematic side view showing an embodiment of the present invention. Reference numeral 5 denotes an atmospheric heating furnace, and the front side (upstream side) of the heating furnace 5 has a plate shape whose upper part is vertically suspended from a ceiling surface. A gas chamber 4 for sealing composed of an upstream chamber 2 and a downstream chamber 3 which are partitioned forward and backward by a partition portion 1 and formed so as to communicate with the lower side is disposed, and a downstream chamber of the gas chamber 4 for sealing is disposed. The upper part of 3 is connected to a preheating chamber / carry-in passage 6 to the heating furnace 5.

  7 is a roller for transporting the article to be heated 8, and 9 is an elevating device installed in each of the upstream chamber 2 and the downstream chamber 3 of the sealing gas tank 4. Although an example of a pantograph shape that can be vertically expanded and contracted by cylinder driving is shown, the mounting table can be configured to simply move up and down by cylinder driving.

  Then, when the article 8 to be heated is placed on the roller 7 by the driving device (not shown) from the carry-in entrance 10 and comes above the upstream chamber 2 of the sealing gas tank 4, it is transferred to the lifting device 9a and lifted and lowered. The heated product 8 on the device 9a is lowered together with the lifting device 9a and transferred onto another roller 7 disposed on the bottom of the sealing gas tank 4, and the processed product 8 on the roller 7 is stored in the tank. 4 Passes the lower side of the lower end of the partition 1 separated from the bottom and enters the downstream chamber 3, and then the processed product 8 is moved and lifted onto the lifting device 9 b in the downstream chamber 3. 5 is transferred onto a roller 7 installed in a preheating chamber / carrying-in passage 6 leading to 5, and carried into the heating furnace 5 through the carrying-in passage 6 and subjected to heat treatment.

  Further, a sealing gas tank 4 having the same configuration as described above is also disposed on the (rear side) of the heating furnace 5, and the treated product 8 after the heat treatment is a slow cooling chamber / unloading passage connected to the heating furnace 5. 11, passes from the upstream side chamber 2 in the sealing gas tank 4 to the downstream side chamber 3 through the lower side of the lower part of the partition part 1, is lifted by the lifting device 9 b, and is moved outside from the carry-out port 12 by the carry-out roller 7. It is carried out.

  In both the sealing gas tanks 4 before and after the heating furnace 5, a sealing gas 13 that is heavier than the atmosphere gas in the furnace of the heating furnace 5 (that is, has a higher density) and heavier than the outside air is accommodated. The gas 13 is supplied so that the upper surface of the gas 13 is always above the lower end of the partition 1.

Although the atmosphere in the heating furnace 5 varies depending on the purpose of the heat treatment, since the furnace atmosphere gas is usually one of H ₂ , N ₂ , Ar vapor, CO ₂ or CO gas, or a mixed gas thereof, Ar gas or CO ₂ gas heavier than these is used as the sealing gas 13.

Further, Ar gas and CO ₂ gas as the sealing gas 13 are heavier than the outside air, and if necessary, the cooling gas 14 is wound around the outer periphery of the sealing gas tank 4 to be cooled. In this case, it is possible to prevent outside air from entering the heating furnace 5 via the sealing gas tank 4.

The heating furnace 5 is formed with a long tunnel-shaped heating chamber 5c surrounded by a heat insulating material 5b inside the steel outer shell 5a, and an inlet 17 provided on the upper side of the heating chamber 5c. To furnace atmosphere gas such as H ₂ gas and N ₂ gas. Moreover, since the said partition part 1 can be suspended and fixed in each gas tank 4 from the same height position as the ceiling surface of the carrying-in channel | path 6 to the heating furnace 5, and the carrying-out channel | path 11, it shows in FIG. As described above, when the heating furnaces 30 to 32 are used side by side as in a third embodiment (see FIG. 3) to be described later, The moving beds of these heating furnaces 30 to 32 can be constructed on the same plane.

Further, a sealing gas 13 such as Ar gas or CO ₂ gas is supplied into the both sealing gas tanks 4 from an inlet 15 provided below the side walls thereof. It is made to overflow from the overflow outlet 16 provided above the same wall.

  As shown in FIG. 4, as an example, the overflow outlet 16 is provided with an atmospheric gas discharge damper 18 and a sealing gas overflow damper 19, and the atmospheric gas discharge port 16a and the sealing gas discharge port 16b are It is desirable that they are provided at the same location so as to be discharged together from the overflow outlet 16, and the exhaust gas is adjusted to dilute and discharge the atmospheric gas with the sealing gas.

  Further, the height of the overflow outlet 16 is always above the lower end of the partition portion 1 and is positioned between the atmospheric gas level and the sealing gas level in the sealing gas tank 4. Install. As a result, the sealing gas 13 dilutes and leaks the atmospheric gas in the furnace 5, so that the structure of the frame curtain can also eliminate the burner and the like, and the problem due to the influence of heat and the like can be solved.

  In addition, although the roller conveyor 7 is used in the drawing as the conveying device for the heat-treated product 8, the structure and the driving mechanism of the roller conveyor 7 are not the gist of the present invention, and the detailed description thereof is here. Omitted.

Since the article 8 to be heated is brought into contact with the sealing gas 13 such as Ar gas or CO ₂ gas in the sealing gas tank 4a as described above, it is sent into the heating furnace 5. As a result, oxygen, oil, and the like adhering to the heat-treated product 8 are washed. As a secondary effect, the heat-treated product 8 is subjected to good heat treatment.

In the above embodiment, when the furnace atmosphere gas is H ₂ and the sealing gas is Ar gas, the density of the H ₂ gas when the temperature of the furnace atmosphere gas is 1120 ° C. is 0. was 02kg / m ^3, the density of the Ar gas for sealing when the temperature of the sealing gas tank 4 and 30 ° C. is 1.57 kg / m ^3, the pressure of the furnace atmosphere gas is about 10Pa Therefore, the furnace atmosphere gas (H ₂ ) is sealed (sealed) with a heavier sealing gas (Ar gas).

  FIG. 2 is a schematic side view showing the second embodiment. As is apparent from FIG. 2, unlike the above embodiment, it is driven by a drive roller 21 as a conveying device for the article to be heated 8 in the heating furnace 5. The mesh belt conveyor 20 is used, and the upstream side (loading side) gas sealing tank 4a and the downstream side (unloading side) gas sealing tank 4b to the heating furnace 5 are connected by a communication line 22. The sealing gas 13 can be simultaneously supplied from the supply port 23 to the gas sealing tanks 4 a and 4 b before and after the heating furnace 5 by providing a sealing gas 13 supply port 23 in the middle of the communication line 22. It is like that.

  In FIG. 2, unlike in FIG. 1, the gas sealing tanks 4 a and 4 b are provided with a lifting device 9 that lifts and lowers the article to be heated 8 so as to be immersed in the sealing gas 13. One unit is installed in 4b, and the elevating device 9 is not provided in each of the upstream chamber 2 and the downstream chamber 3 as shown in FIG. In the case of FIG. 2, the elevating device 9 can move not only in the vertical direction but also in the back-and-forth direction, so that the article 8 to be heated is received and lowered above the upstream chamber 2 and passes directly below the partition 1. It is configured so that it can enter the downstream chamber 3, rise in the downstream chamber 3, and be placed on the conveyor 20.

  In FIG. 2, the same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  According to the second embodiment, it is possible to simplify the control device for the sealing gas 13 supplied into the gas sealing tanks 4a and 4b, and to reduce the cost of the entire device.

FIG. 3 is a schematic side view showing the third embodiment. As is clear from FIG. 3, a degreasing furnace 30 in an oxidizing atmosphere, a decarburizing furnace 31 in an H ₂ atmosphere, and a sintering furnace 32 in an Ar gas atmosphere, As the sealing gas 13 that is connected via the gas sealing tanks 4 and supplied into the gas sealing tanks 4, the heaviest CO ₂ gas is put in, thereby leaking the atmosphere in each furnace to the outside. In other words, it is possible to carry out the degreasing process, the decarburizing process, and the sintering process continuously, with little mixing of other gases into the furnace from the outside.

  According to the third embodiment, since the gas sealing tank 4 having the same configuration can be used, the entire apparatus can be made compact and the cost can be reduced.

1 is a conceptual side view showing a first embodiment of the present invention. It is a conceptual side view which similarly shows 2nd Example. It is a conceptual side view which shows 3rd Example similarly. It is expansion sectional explanatory drawing of the gas overflow outlet provided in the gas tank for sealing.

Explanation of symbols

1-partition part 2-upstream side chamber 3-downstream side chamber 4-sealing gas tank 5-heating furnace 6 (preheating chamber) carrying-in passage 6
7-Roller conveyor 8-Heated product 9-Lifting device 10-Carry-in port 11-(Slow cooling chamber) Carry-out passage 12-Carry-out port 13-Sealing gas 14-Cooling pipe 15-Sealing gas inlet 16-Gas overflow outlet 17-Atmospheric gas inlet 18-Damper 19-Damper 20-Belt conveyor 21-Driving roller 22-Sealing gas communication passage 23-Sealing gas supply port 30-Degreasing furnace 31-Degreasing Charcoal furnace 32-sintering furnace

Claims (6)

A sealing gas tank composed of an upstream chamber and a downstream chamber, the upper portion of which is partitioned by a partitioning portion and communicated with the lower portion, is connected to a carry-in passage or a carry-out passage to the heating furnace, and the inside of the sealing gas Is supplied with a sealing gas heavier than the atmosphere gas of the heating furnace and heavier than the outside air so that the upper surface of the sealing gas is always above the lower end of the partition, After passing from the side chamber below the lower end of the partition part and entering the downstream chamber, and passing through the sealing gas tank, it is carried into the furnace through the carry-in passage, and after the heat treatment. An atmosphere gas sealing method for a heating furnace, wherein the heat-treated product is allowed to pass through a sealing gas tank through a carry-out passage in the same manner as described above and then carried out of the furnace. A gas tank for sealing composed of an upstream chamber and a downstream chamber, the upper part of which is partitioned by a partitioning part and the lower part of which communicates, is connected to a carry-in passage or a carry-out passage to the heating furnace, Pass the lower side from the lower end of the partition from the upstream side chamber and enter the downstream side chamber, and then pass through the sealing gas tank, then carry it into the furnace from the carry-in passage, or in the heating furnace The heat-treated product after the heat treatment is passed through the unloading passage in the same manner as described above and then transported to the outside of the furnace after being passed through the sealing gas tank. In the heating furnace, a sealing gas that is heavier than the atmosphere gas in the furnace and heavier than the outside air is accommodated in a state where the upper surface of the sealing gas is always above the lower end of the partition. A heating furnace configured to seal the atmospheric gas of Atmospheric gas sealing device. A heating furnace comprising the atmosphere gas sealing device according to claim 2 on both the carry-in passage side and the carry-out passage side of the heating furnace. The gas for sealing in both tanks is brought into a communication state by connecting the gas tanks for sealing in the atmosphere gas sealing device provided on the carry-in passage side and the carry-out passage side by communication pipes. Item 4. The heating furnace according to Item 3. The heating furnace according to claim 3 or 4, wherein the sealing gas is Ar gas or CO ₂ gas. The heating furnace according to claim 5, wherein the cooling is performed so that the Ar gas or the CO ₂ gas is heavier than the atmosphere gas in the furnace and heavier than the outside air.

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