Treatment furnace

Abstract

A treatment furnace (10) for treating an object (S) by heating with microwaves comprises: a retort (2) into which the object (S) is carried; and an outer shell part (3) configured so as to surround the retort (2). A microwave generation device (6) is provided on an inner surface of the outer shell part (3), and a hole (8) for letting microwaves generated from the microwave generation device (6) into the retort (2) is formed in the retort (2).

Description

Processing furnace

[0001] The present invention relates to a processing furnace for heating and processing an object to be processed with microwaves.

[0002] Conventional processing furnaces that heat objects to be processed by microwaves without using flames, electric heaters, etc. include those disclosed in Patent Documents 1 and 2.

[0003] Utility Model Registration No. 3111156 JP 60-59560 A JP 2002-371366 A JP 2008-300279 A

[0004] In the processing furnaces disclosed in Patent Documents 1 and 2, microwaves generated from a microwave generator are guided into the furnace by a metallic waveguide. However, as disclosed in Patent Documents 3 and 4, the waveguide itself acts as an electrical resistor, generating heat and thereby reducing microwave output. In addition, thermal expansion of the waveguide causes a decrease in thermal conductivity between the waveguide and each component of the processing furnace.

[0005] Therefore, an object of the present invention is to provide a processing furnace with improved energy efficiency by introducing microwaves into a retort without using a waveguide.

[0006] The present invention is a processing furnace that heats and processes an object to be processed with microwaves, and includes: a retort into which the object to be processed is carried; and an outer shell configured to surround the retort, wherein a microwave generator is provided in the outer shell; and the retort has holes formed therein that allow microwaves generated from the microwave generator to enter the retort.

[0007] According to the above configuration, microwaves from a microwave generator provided in the outer shell enter the retort through holes formed in the retort, so there is no need to guide the microwaves into the retort using a waveguide, and it is possible to suppress the reduction in output due to heat generation in the waveguide itself and the impact on each component due to thermal expansion of the waveguide.

[0008] According to the present invention, by introducing microwaves into the retort without using a waveguide, a more energy efficient processing furnace can be provided.

[0009] 1 is a schematic diagram of a processing furnace according to an embodiment of the present invention; FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1; FIG. 3 is a top view of the vicinity of a hole in a retort; and FIG. 4 is an enlarged view of the hole in FIG. 2. FIG. 4 is a schematic cross-sectional view of a processing furnace according to another embodiment of the present invention, in which three circular holes are formed in the circumferential direction of the upper wall of the retort when viewed from above. FIG. 5 is a top view of the vicinity of the hole in the retort of FIG. 5; and FIG. 6 is a schematic cross-sectional view of a processing furnace according to another embodiment of the present invention, in which three substantially square holes are formed in the circumferential direction of the upper wall of the retort when viewed from above. FIG. 7 is a top view of the vicinity of the hole in the retort of FIG. 7; and FIG. 8 is an enlarged view of a hole 91 of FIG. 5. and an enlarged view of a hole 92 of FIG. 7.

[0010] Fig. 1 is a schematic diagram of a treatment furnace 10 according to an embodiment of the present invention, and Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. As shown in Fig. 1 and Fig. 2, the treatment furnace 10 is a treatment furnace that heats and treats a workpiece S with microwaves, and includes a feeder 1 into which the workpiece S is fed, a retort 2 into which the workpiece S is gradually carried by the feeder 1, an outer shell 3 configured to surround the retort 2, a recovery container 4 in which the workpiece S treated in the retort 2 is recovered, and an exhaust port 5 that releases gas generated by the treatment of the workpiece S to the outside.

[0011] The outer shell 3 has a cylindrical shape with a circular cross section, and a microwave generator 6 that generates microwaves is provided on the upper wall 31 of the outer shell 3. In this embodiment, multiple microwave generators 6 are provided at intervals in the axial direction X of the retort 2. The outer shell 3 is made of a metal that functions as an electromagnetic shield to prevent the penetration and leakage of electromagnetic waves, such as rolled steel (SS material, etc.). The outer shell 3 may also have a rectangular cylindrical shape with a square cross section. The upper wall 31 may be any wall located above the center of the outer shell 3 in the vertical direction, and may be horizontal or inclined.

[0012] The outer shell 3 is provided with a protective member 7 that protects the microwave generator 6 from gases generated by processing the workpiece S. The protective member 7 is attached to the upper wall 31 of the outer shell 3 so as to cover the entire microwave generator 6, and is made of a material that is easily permeable to microwaves but not permeable to the gases, such as alumina, quartz, or Teflon (registered trademark).

[0013] The retort 2 has a cylindrical shape with a circular cross section, and one or more holes 8 are formed in the upper wall 21 of the retort 2 to allow microwaves generated from the microwave generator 6 to enter the retort 2. The retort 2 is made of a metal with high heat resistance and corrosion resistance, such as stainless steel (SUS310S, etc.), in consideration of treating the workpiece S. The retort 2 and the outer shell 3 are arranged concentrically.

[0014] The retort 2 receives the material S to be treated supplied from the feeder 1 through an inlet 22, heat-treats the material S in the retort 2, and then discharges the material S from an outlet 23. The material S discharged from the retort 2 is collected in a collection container 4 provided below the outlet 23. An exhaust port 5 is provided above the outlet 23, which releases gas generated by the heat treatment of the material S to the outside.

[0015] The retort 2 is slightly inclined downward from the entrance 22 toward the exit 23, and is configured to be swingable left and right with respect to the axial direction X of the retort 2. Therefore, the material S received from the entrance 22 is automatically transported within the retort 2 to the exit 23 by the swinging of the retort 2.

[0016] FIG. 3 is a top view of the vicinity of the hole 8 of the retort 2. As shown in FIGS. 1 to 3, a plurality of holes 8 are formed in the upper wall portion 21 of the retort 2 and are spaced apart in the axial direction X of the retort 2. The holes 8 are disposed directly below the microwave generator 6. If the length L1 of the hole 8 in the axial direction X of the retort 2 is longer than the length L2 of the microwave generator 6, heat in the retort 2 will easily escape upward. On the other hand, if the length L1 of the hole 8 in the axial direction X of the retort 2 is shorter than the length L2, microwaves will not sufficiently enter the retort 2, resulting in poor thermal efficiency. Therefore, it is preferable that the length L1 of the hole 8 in the axial direction X of the retort 2 be the same as the length L2 of the microwave generator 6. Furthermore, the hole 8 has a rectangular shape when viewed from above the retort 2.

[0017] Figure 4 is an enlarged view of the hole 8 in Figure 2. As shown in Figure 4, the corners 8a of the hole 8 are chamfered. The entire surface of the hole 8 may also be curved. A protrusion 812 that protrudes inward is formed on the side wall surface 81 that forms the hole 8. In addition, in a cross section perpendicular to the axial direction X of the retort 2, the hole 8 opens at an angle of up to ±θa degrees from the vertically upward direction Y. For example, θa is 30 to 45 degrees.

[0018] (Treatment of the object S to be treated by the treatment furnace 10) The object S to be treated is first fed into the feeder 1. The object S to be treated fed into the feeder 1 is gradually carried into the cylindrical retort 2 by the feeder 1.

[0019] When the object to be treated S is carried into the retort 2, the retort 2 swings left and right in the circumferential direction relative to the axial direction X of the retort 2, and the microwave generator 6 provided on the upper wall 31 of the outer shell 3 is activated. Microwaves generated by the microwave generator 6 enter the retort 2 through holes 8 formed in the upper wall 21 of the retort 2. The object to be treated S in the retort 2 is then irradiated with the microwaves and heated.

[0020] The retort 2 is slightly inclined downward (approximately 1 to 2 degrees) from the entrance 22 to the exit 23. Furthermore, by the left-right oscillation of the retort 2, the workpiece S in the retort 2 is stirred, uniformly heat-treated by microwaves, and transported from the entrance 22 to the exit 23. Here, the angle of the left-right oscillation of the retort 2 is set to, for example, less than ±θa degrees from ±θa degrees to the contact point P where the upper surface S' of the workpiece S contacts the inner surface of the retort 2, taking into account the maximum angle of ±θa degrees from the vertically upward direction Y of the hole 8, so as to prevent the workpiece S from being released from the hole 8. However, if a protrusion 812 is provided as shown in FIG. 2, the workpiece S can be oscillated at a greater angle. Note that although the upper surface S' of the workpiece S is assumed to be substantially horizontal here, the upper surface S' of the workpiece S may also be inclined.

[0021] The workpiece S that has been heat-treated in the retort 2 is discharged from the outlet 23 and collected in the collection container 4. Gases generated by heat-treating the workpiece S are released to the outside from an exhaust port 5 provided above the outlet 23. The microwave generator 6 is covered with a protective member 7, and is therefore not exposed to the gases generated by heat-treating the workpiece S.

[0022] The processing furnace 10 having the above-described configuration can provide the following effects.

[0023] (1) Microwaves from the microwave generator 6 provided in the outer shell 3 enter the retort 2 through the holes 8 formed in the retort 2. This eliminates the need to guide the microwaves into the retort 2 using a waveguide, and can suppress the reduction in output due to heat generation in the waveguide itself and the impact of thermal expansion of the waveguide on each component.

[0024] (2) The corners 8a of the holes 8 are chamfered, which prevents microwaves entering the retort 2 from concentrating on the sharp parts of the holes 8, causing overheating or sparks. Although the chamfering may be a typical shape in which the corners are cut off at 45 degrees, it is preferable to chamfer the corners with a curved surface as shown in Figure 4, as this eliminates sharp parts.

[0025] (3) The microwave generator 6 is provided on the inner surface of the upper wall portion 31 of the outer shell portion 3, the hole 8 is provided in the upper wall portion 21 of the retort 2, and the retort 2 is configured to oscillate at an angle that prevents the material S to be treated inside the retort 2 from being released outside the retort 2 through the hole 8. Therefore, the material S to be treated inside the retort 2 can be stirred and subjected to uniform heat treatment without releasing the material S from the hole 8.

[0026] (4) A protrusion 812 that protrudes inward is formed on the side wall surface 81 of the hole 8, so that the workpiece S in the retort 2 can be prevented from being released outside the retort 2 through the hole 8.

[0027] (5) The retort 2 has a cylindrical shape. If the opening angle of the holes 8 in a cross section perpendicular to the axial direction X of the retort 2 is too small, microwaves will not easily enter, and if the opening angle is too large, the oscillation angle will be too small and the workpiece S will not be able to be sufficiently stirred. Therefore, in order to improve the heating efficiency of the workpiece S, it is preferable to open the holes 8 at an angle of ±30 degrees to ±45 degrees from the vertical upward direction Y.

[0028] (Another embodiment) In the above embodiment, the hole 8 is configured to be widely opened at one location so as to have an angle of up to ±θa degrees from the vertically upward direction Y, but a plurality of holes may be provided in the circumferential direction of the upper wall portion 21 of the retort 2.

[0029] FIG. 5 is a schematic cross-sectional view of a processing furnace 10 according to another embodiment of the present invention, in which three circular holes 91 (91a, 91b, 91c) are formed in the circumferential direction of the upper wall portion 21 of the retort 2 when viewed from above. FIG. 6 is a top view of the vicinity of the hole 91 of the retort 2 in FIG. 5. FIG. 7 is a schematic cross-sectional view of a processing furnace 10 according to another embodiment of the present invention, in which three substantially square holes 92 (92a, 92b, 92c) are formed in the circumferential direction of the upper wall portion 21 of the retort 2 when viewed from above. FIG. 8 is a top view of the vicinity of the hole 92 of the retort 2 in FIG. 7. FIGS. 5 and 7 differ only in the shapes of the holes 91 and 92 when viewed from above. In the other embodiments of FIGS. 5 and 7, the holes 91 and 92 are different from those of the above embodiment, but the other configurations are the same as those of the above embodiment. Therefore, in the description of the other embodiment, the same parts as those of the above embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0030] 5 and 7 , a plurality of holes 91 and 92 are provided at intervals in the axial direction X of the retort 2. The holes 91 and 92 are arranged directly below the microwave generator 6, and if the length L1 of the holes 91 and 92 in the axial direction X of the retort 2 is longer than the length L2 of the microwave generator 6, heat in the retort 2 will be more likely to escape upward, whereas if it is shorter than the length L2, microwaves will not sufficiently enter the retort 2, resulting in poor thermal efficiency. Therefore, it is preferable that the length L1 of the holes 91 and 92 in the axial direction X of the retort 2 coincide with the length L2 of the microwave generator 6.

[0031] Fig. 9 is an enlarged view of the hole 91 in Fig. 5, and Fig. 10 is an enlarged view of the hole 92 in Fig. 7. The corners 91d, 92d of the holes 91 and 92 in Fig. 9 and Fig. 10 are chamfered. The chamfering may be a typical shape in which the corners are cut off at 45 degrees, but as shown in Fig. 9 and Fig. 10, chamfering with a curved surface is preferable because it eliminates sharp parts and makes it less likely for localized overheating or sparks to occur.

[0032] Furthermore, in a cross section perpendicular to the axial direction X of the retort 2, the hole 91 opens at an angle of a maximum of +θb degrees (hole 91c) and a maximum of −θb degrees (hole 91a) from the vertically upward direction Y, and the hole 92 opens at an angle of a maximum of +θc degrees (hole 92c) and a maximum of −θc degrees (hole 92a) from the vertically upward direction Y. θb and θc are the same as θa, for example, 30 to 45 degrees. The angle of left-right oscillation of the retort 2 is, as in the above embodiment, less than ±θb' degrees or less than ±θc' degrees from ±θb degrees or ±θc degrees to the contact point P where the upper surface S' of the workpiece S contacts the inner surface of the retort 2. Furthermore, as in the above embodiment, the upper surface S' may not be substantially horizontal but may be inclined.

[0033] According to the configuration of the above-described other embodiment, the circumferential opening area of ​​holes 91 and 92 is smaller than the circumferential opening area of ​​hole 8 compared to the above-described embodiment, but heat radiation from holes 91 and 92 within retort 2 is reduced and the area over which retort 2 is connected at the top is increased, thereby suppressing thermal deformation of retort 2.

[0034] 11 is a schematic cross-sectional view of a processing furnace 10 according to yet another embodiment of the present invention, in which three circular holes 91 (91a, 91b, 91c) are formed in the circumferential direction of the upper wall portion 21 of the retort 2 when viewed from above, and a plurality of microwave generators 6 are provided in the circumferential direction of the upper wall portion 31. A plurality of microwave generators 6 may be provided in the circumferential direction of the upper wall portion 31 so as to face the holes 91. As a result, it is possible to improve the penetration of microwaves into the retort 2. The shape of the holes 91 may be approximately square.

[0035] The present invention and embodiments can be summarized as follows.

[0036] (1) One embodiment of the present invention is a processing furnace for heating and processing an object to be processed with microwaves, comprising: a retort into which the object to be processed is carried; and an outer shell configured to surround the retort, wherein a microwave generator is provided in the outer shell; and the retort has holes formed therein to allow microwaves generated from the microwave generator to enter the retort.

[0037] According to the configuration (1), microwaves from a microwave generator provided in the outer shell enter the retort through holes formed in the retort, so there is no need to guide the microwaves into the retort using a waveguide, and it is possible to suppress the reduction in output due to heat generation in the waveguide itself and the impact on each component due to thermal expansion of the waveguide.

[0038] (2) In the above configuration (1), the corners of the hole are chamfered.

[0039] According to the configuration (2), by chamfering the corners of the hole, it is possible to prevent microwaves entering the retort through the hole from concentrating on the sharp part of the hole, causing overheating or sparks.

[0040] (3) In the configuration (1) or (2), the micro-generator is provided on the upper wall or inclined portion of the outer shell, the hole is provided on the upper wall of the retort, and the retort is configured to oscillate at an angle such that the material to be treated inside the retort is not released outside the retort through the hole.

[0041] According to the above configuration (3), the material to be treated in the retort can be stirred and uniformly heated without being released from the holes.

[0042] (4) In any one of the above configurations (1) to (3), a protrusion that protrudes inward is formed on the side wall surface of the hole.

[0043] According to the configuration (4), by providing a protrusion that protrudes inward on the side wall surface of the hole, it is possible to prevent the material to be treated in the retort from being released from the hole to the outside of the retort, and the angle of oscillation can be increased to achieve better stirring.

[0044] (5) In any one of the configurations (1) to (4), the retort has a cylindrical shape, and in a cross section perpendicular to the axial direction of the retort, the hole opens at an angle of ±30 degrees to ±45 degrees from the vertically upward direction.

[0045] According to the configuration (5), the holes are opened at an angle of ±30 degrees to ±45 degrees from the vertically upward direction, which makes it easier for microwaves to enter the retort, allowing the material to be thoroughly stirred, and improving the heating efficiency of the material to be treated.

[0046] Various modifications and variations may be made without departing from the spirit and scope of the present invention as set forth in the following claims.

[0047] The present invention provides a processing furnace with superior energy efficiency by introducing microwaves into the retort without using a waveguide, and is therefore of great industrial value.

[0048] DESCRIPTION OF SYMBOLS 1 Feeder 2 Retort 21 Upper wall 22 Inlet 23 Outlet 3 Outer shell 31 Upper wall 4 Recovery container 5 Exhaust port 6 Microwave generator 7 Protective member 8 Hole 8a Corner 81 Side wall surface 812 Projection 91 Hole 91a Hole 91b Hole 91c Hole 91d Corner 92 Hole 92a Hole 92b Hole 92c Hole 92d Corner 10 Processing furnace L1 X-direction length of hole L2 X-direction length of microwave generator P Contact point S Workpiece S' Top surface of workpiece X Axial direction Y Vertically upward direction

Claims

1. A processing furnace for heating and processing an object to be processed with microwaves, comprising: a retort into which the object to be processed is carried; and an outer shell configured to surround the retort, a microwave generator is provided on the inner surface of the outer shell, and a hole is formed in the retort to allow microwaves generated from the microwave generator to enter the retort.

2. The process furnace of claim 1, wherein the corners of said holes are chamfered.

3. The treatment furnace of claim 1, wherein the microwave generating device is provided on the inner surface of the upper wall of the outer shell, the hole is provided in the upper wall of the retort, and the retort is configured to oscillate at an angle such that the material to be treated within the retort is not released outside the retort through the hole.

4. The processing furnace according to claim 1, wherein a protrusion protruding inward is formed on a side wall surface of the hole.

5. A treatment furnace as described in any one of claims 1 to 4, wherein the retort has a cylindrical shape, and in a cross section perpendicular to the axial direction of the retort, the hole opens at an angle of ±30 degrees to ±45 degrees from the vertically upward direction.

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