JP2011149561A - Heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating device capable of significantly unifying a fluidizing state and a heating state of a powder and granular material regardless of a place in a fluid bed and a size of the fluid bed, and properly heating a workpiece while keeping high heat efficiency. <P>SOLUTION: This heating device for heating the metallic workpiece 1, applies the powder and granular material 2 heated by a high-temperature gas as a heat medium, includes the fluid bed 3 in which the workpiece 1 is immersed, uses porous metal heated to a high temperature and having air permeability as a bottom plate 4 of the fluid bed 3, and is constituted to introduce a high temperature gas passing through the bottom plate 4 into the fluid bed 3. Since the high temperature gas can be introduced into the fluid bed 3 uniformly from the entire bottom plate 4, the fluidizing state and the heating condition can be properly unified. Further, since the bottom plate 4 itself is heated to the high temperature, loss in conveying hot air and pressure loss hardly generate. Thereby, high heat efficiency can be kept. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heating device for heating a metal workpiece.

  By heat-treating metal workpieces, tempering (quenching and tempering) amorphous metal parts, etc., or heating metal parts such as castings before painting to increase the processing speed in the painting process Things are already done widely.

  As a conventional heating apparatus for performing this kind of heat treatment, a combustion gas atmosphere furnace that mainly generates a combustion gas using gas or oil as a fuel, and heats a workpiece that is a heating object such as a casting with the combustion gas. (For example, Patent Document 1) is generally used, and the workpiece is heated using combustion gas as a heat medium.

  However, since the combustion gas has a small heat capacity, when the combustion gas is used as a heat medium, there is a disadvantage that the heat transfer rate to the metal workpiece is low and the heat treatment speed is low. Moreover, since fresh air must be constantly replenished in order to supply oxygen necessary for the combustion gas, there is also a disadvantage that the thermal efficiency is lowered.

  As a heat treatment method for improving these drawbacks, a gas ejection pipe for ejecting a high-temperature gas such as combustion gas is provided at the bottom of a fluidized bed in which powder particles are accumulated so as to extend in the horizontal direction, and this gas ejection pipe Japanese Patent Application Laid-Open No. H10-228561 proposes that a granular material is caused to flow and heated by a high-temperature gas ejected from, and a metal work is immersed in the fluidized bed for heating. The gas ejection pipe is formed with holes for ejecting high temperature gas at appropriate intervals. Further, in this type of heating device, instead of using combustion gas as the high temperature gas, an electric heater for heating the exhaust gas discharged from the fluidized bed is provided as a heating source, and the high temperature gas heated by this electric heater is provided. It is conceivable to send the gas to the gas ejection pipe by a blower or the like.

  As described above, when the workpiece is heated by immersing it in a fluidized bed with the granular material as a heat medium, the heat capacity of the granular material is large, so the heat transfer rate to the metal workpiece with which the granular material abuts is several times. It becomes high and the heat processing speed of a workpiece | work can be raised significantly. Further, by using an electric heater as a heating source, it is not necessary to always replenish fresh air as in the case of using combustion gas, so that a decrease in thermal efficiency can be suppressed.

JP 2009-57621 A JP 2004-293899 A

  However, as described above, when the gas ejection pipe having the hole is formed at the bottom of the fluidized bed, a large amount of high-temperature gas is supplied to the hole of the gas ejection pipe and the vicinity thereof. On the other hand, the supply amount of the high-temperature gas is extremely reduced at a location where the gas ejection pipe is not disposed or at a location away from the hole of the gas ejection pipe. Therefore, in the horizontal plane where the gas ejection pipe at the bottom of the fluidized bed is arranged, a large deviation occurs in the distribution state of the hot gas, and if the workpiece is immersed in such a region, the heating state of the workpiece is not uniform. There is a risk. In order to avoid such problems, high temperature gas diffuses at a location somewhat above the gas jet pipe and its distribution is equalized, so the vertical height of the fluidized bed is increased so that the gas jet pipe It is conceivable to immerse the workpiece at a considerably high position. However, in this case, since the height of the fluidized bed must be increased, there arises a problem that increases the equipment cost and installation space.

  In addition, when a fluidized bed with a large installation area is required so that even a large workpiece can be heat-treated, a long gas ejection pipe is provided in the fluidized bed. The pressure difference between the side and the downstream side becomes large (the pressure at the downstream side becomes smaller). As a result, there is a problem that the flow state and the heating state become non-uniform.

  Furthermore, when the place where the high temperature gas generating section where the electric heater as a heating source is disposed and the fluidized bed are separated, the hot air flow path piping section from the high temperature gas generating section to the fluidized bed is used. There is a problem that the loss of hot air and the pressure loss are increased, thereby reducing the thermal efficiency.

  The present invention solves the above-mentioned problems, and can make the flow state and heating state of the granular material extremely uniform and maintain high thermal efficiency regardless of the part in the fluidized bed and the size of the fluidized bed. However, an object of the present invention is to provide a heating apparatus that can heat the workpiece satisfactorily.

  In order to solve the above-mentioned problems, the present invention is a heating apparatus for heating a metal workpiece, comprising a fluidized bed in which the workpiece is immersed using a granular material heated by a high-temperature gas as a heating medium, The bottom plate is made of a porous metal that is heated and breathable, and is configured to introduce the high-temperature gas that has passed through the bottom plate into the fluidized bed.

  With this configuration, a porous metal that is heated and breathable is used as the bottom plate of the fluidized bed, so that high-temperature gas can be uniformly introduced into the fluidized bed from the entire bottom plate, and the fluidized state becomes uniform. And uniform heating state can be achieved. In addition, since the bottom plate itself is heated, there is almost no loss of hot air conveyance or pressure loss, thereby maintaining high thermal efficiency.

  In addition, the heating device of the present invention is characterized by including induction heating means for induction heating the bottom plate of the fluidized bed. According to this structure, the bottom plate of the fluidized bed is induction-heated by the induction heating means to increase the temperature, and the high-temperature gas that has passed through the bottom plate can be introduced into the fluidized bed.

  In addition, the heating device of the present invention includes an energizing device that energizes the bottom plate of the fluidized bed to bring the bottom plate to a high temperature. According to this configuration, it is possible to introduce a high-temperature gas that has passed through the bottom plate by energizing the bottom plate of the fluidized bed with the energization device to increase the temperature.

  In addition, the heating device of the present invention includes a dust removal filter and a blower, sucks exhaust gas discharged from the fluidized bed, removes dust through the dust removal filter, and then cleans the exhaust gas with the blower. The high temperature gas which consists of exhaust gas is circulated by supplying again in a fluidized bed through the bottom plate of this. With this configuration, by circulating the exhaust gas discharged from the fluidized bed, the amount of heat heated by the bottom plate can be minimized, and a heating device with extremely high thermal efficiency can be realized.

  The heating device of the present invention has a double layer structure in which the wall surface of the fluidized bed has an inner wall surface portion and an outer wall surface portion, and a high temperature composed of exhaust gas discharged from the top of the fluidized bed between the inner wall surface portion and the outer wall surface portion. It is characterized in that a circulation passage for guiding gas to the lower side of the bottom plate is formed. With this configuration, it is extremely compact, and at the same time, the disposition distance of the circulation passage can be extremely shortened, so that the loss of hot air conveyance that escapes from the circulation passage can be minimized, and the inner wall surface of the fluidized bed circulates. Since it is covered from the outside by the use passage, heat leakage from the fluidized bed to the outside can be minimized, and a heating device with extremely high thermal efficiency can be realized.

  According to the present invention, as the bottom plate of the fluidized bed, by using a porous metal that has a high temperature and has air permeability, the fluidized state and the heated state can be made uniform and the reliability can be improved. High heating device can be obtained. Further, since it is not necessary to increase the vertical height of the fluidized bed in order to make the fluidized state uniform and the heated state uniform, there is no increase in equipment costs and installation space. In addition, since the bottom plate itself is heated, there is almost no loss of hot air conveyance or pressure loss, thereby maintaining high thermal efficiency and reducing operating costs.

  Further, the heating device includes induction heating means for induction heating the bottom plate of the fluidized bed, and the induction heating means induction heats the bottom plate of the fluidized bed. By providing an energization device that raises the bottom plate at a high temperature and energizing the bottom plate of the fluidized bed with this energization device, the bottom plate of the fluidized bed can be satisfactorily heated.

  Further, the heating device of the present invention includes a dust removal filter and a blower, sucks exhaust gas discharged from the fluidized bed, removes dust through the dust removal filter, and then cleans the exhaust gas with the fluidizer. The high temperature gas consisting of exhaust gas can be circulated and used by supplying it again into the fluidized bed through the bottom plate, and the amount of heat heated by the bottom plate can be minimized. Can be realized.

  The heating device of the present invention has a double layer structure in which the wall surface of the fluidized bed has an inner wall surface portion and an outer wall surface portion, and a high temperature composed of exhaust gas discharged from the top of the fluidized bed between the inner wall surface portion and the outer wall surface portion. By forming a circulation passage that guides gas to the bottom of the bottom plate, it is extremely compact and at the same time, the loss of hot air conveyance escaping from the circulation passage can be minimized, and the inner wall surface of the fluidized bed circulates. Since it is covered from the outside by the use passage, heat leakage from the fluidized bed to the outside can be minimized, and a heating device with extremely high thermal efficiency can be realized.

It is sectional drawing of the heating apparatus which concerns on embodiment of this invention.

Hereinafter, a heating device according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the heating device according to the embodiment of the present invention is a heating device that heats a metal workpiece 1, and heats a granular material 2 made of ceramic particles or the like heated by a high-temperature gas. And a fluidized bed 3 in which the workpiece 1 is immersed. The bottom plate 4 of the fluidized bed 3 is made of a porous metal such as a foamed metal that has a high temperature and has air permeability, and is configured to introduce the hot gas that has passed through the bottom plate 4 into the fluidized bed 3. ing. Of course, the diameter of the hole of the bottom plate 4 is smaller than the diameter of the granular material so that the granular material 2 does not leak from the bottom plate 4.

  An induction heating coil 5 as induction heating means for induction heating the bottom plate 4 of the fluidized bed 3 is disposed below the bottom plate 4 (FIG. 1 shows a case where two are provided. However, the present invention is not limited to this.) By passing an alternating current through the induction heating coil 5, the bottom plate 4 is heated to a high temperature state. Instead of heating the bottom plate 4 by dielectric heating, the bottom plate 4 may be heated using a porous metal that generates heat due to its resistance when energized.

  The wall surface (outer shell portion) of the fluidized bed 3 has a double structure having an inner wall surface portion 6 and an outer wall surface portion 7. Between the inner wall surface portion 6 and the outer wall surface portion 7, the top of the fluidized bed 3 (in detail, In the fluidized bed 3, a hot plate gas (indicated by an arrow in FIG. 1) made of exhaust gas discharged from the fluidized bed space 3 b above the fluidized bed main body 3 a where the granular material 2 is stored is a bottom plate. A circulation passage 8 that leads to the lower side of 4 is formed. Further, a blower 9 is disposed at the top of the fluidized bed 3, and exhaust gas exhausted from the fluidized bed 3 (specifically, the fluidized bed space 3 b) is sucked by the blower 9, and the circulation passage 8 and the induction are guided. After being sent to the bottom plate 4 side through the heating coil 5 location and heated when passing through the bottom plate 4, the inside of the fluidized bed 3 again (specifically, in the fluidized bed main body 3 a surrounded by the inner wall surface portion 6). As a result, a high-temperature gas composed of exhaust gas circulates in the fluidized bed 3.

  The fluidized bed space 3b above the fluidized bed body 3a is provided with a dust removal filter 10 that filters and removes dust contained in the exhaust gas discharged from the fluidized bed body 3a. The exhaust gas discharged from 3a is purified by passing through the dust filter 10, and the purified exhaust gas (high temperature gas) passes through the circulation passage 8 and the place where the induction heating coil 5 is disposed to the bottom plate 4 side. It is configured to be sent to. Here, as the dust removal filter 10, it is preferable to use a metal foam plate, but the present invention is not limited to this.

  In addition, 11 in FIG. 1 is an electric chain block as an example of the conveying means of the workpiece 1, and the wire 11a provided on the electric chain block 11 is moved up and down in accordance with the control instruction of the control means not shown. The immersion time of the work 1 in the fluidized bed main body 3a can be controlled. Reference numeral 12 denotes a sand seal portion that prevents the powder 2 from leaking out to the circulation passage 8 side.

  Reference numeral 13 denotes an outside air introduction blower for introducing outside air, which is configured to be introduced into a lower portion of the bottom plate 4 by being driven as necessary for adjusting the heating atmosphere component of the work 1 and adjusting the heating temperature. Thus, a pressure is applied to the lower part of the bottom plate 4 in the fluidized bed 3 to function as a pressure chamber, and the inflow amount of high-temperature gas from the bottom plate 4 can be increased.

  In the above configuration, by passing an alternating current through the induction heating coil 5, the bottom plate 4 is heated to a high temperature state, and the bottom plate 4 is made of a porous metal such as a foam metal having air permeability. The high-temperature gas that has passed through 4 rises in the fluidized bed main body 3a to flow and heat the powder 2 as a heat medium. Accordingly, when the workpiece 1 is immersed in the powder body 2 of the fluidized bed main body 3a that is in a fluidized state, the workpiece 1 is heated by coming into contact with the powder body 2 in the fluidized state. . Further, the exhaust gas discharged from the fluidized bed main body 3a is purified by passing through the dust removal filter 10 disposed in the fluidized bed space 3b, and the purified exhaust gas (high temperature gas) becomes a circulation passage. 8 and the induction heating coil 5 are disposed to the bottom plate 4 side, and as a result, a high-temperature gas composed of exhaust gas circulates in the fluidized bed 3.

  In this case, the bottom plate 4 of the fluidized bed 3 (fluidized bed main body 3a) is made of a porous metal that has a high temperature and is air permeable. It can be introduced into the flow, and the flow state and the heating state can be made uniform. Further, regardless of the installation area of the fluidized bed 3 (fluidized bed main body 3a), the high temperature gas is uniformly introduced into the fluidized bed main body 3a from the entire bottom plate 4, so that the high temperature gas is ejected from the gas ejection pipe. As in the case, it is not necessary to increase the vertical height of the fluidized bed in order to make the fluidized state uniform and the heated state uniform, and as a result, the equipment cost and installation space are not increased. Accordingly, it is possible to reduce the equipment cost and to suppress the increase in installation space for achieving a uniform flow state and a uniform heating state.

  In addition, since the bottom plate 4 itself of the fluidized bed 3 (fluidized bed main body 3a) is heated to a high temperature, the location where the heating source and the fluidized tank are separated from each other as in the prior art. The occurrence of the problem of causing a hot air conveyance loss and pressure loss in the air is eliminated, and almost no hot air conveyance loss or pressure loss occurs, whereby high thermal efficiency can be maintained.

  Moreover, according to the said structure, by providing the induction heating coil 5 as an induction heating means to induction-heat the bottom plate 4 of the fluidized bed 3, it is a comparatively simple structure, and the bottom plate 4 of the fluidized bed 3 by the induction heating coil 5. The high temperature gas that has passed through the bottom plate 4 can be satisfactorily introduced into the fluidized bed 3. As described above, instead of this, the bottom plate 4 may be heated using a porous metal that generates heat due to its resistance when energized. In this case, since there is nothing that obstructs the passage of gas passing through the bottom plate 4 such as when the induction heating coil 5 is provided, there is an advantage that the ventilation state is good. In any case, the fluidized bed 3 can be controlled to a desired temperature relatively easily and appropriately by adjusting the power supplied to the induction heating coil 5 and the bottom plate 4.

  In addition, since the dust filter 10 is provided as described above and the dust filter 10 is disposed in the fluidized bed space 3b above the fluidized bed body 3a, the granular material 2 and dust are transferred to the fluidized bed body 3a and the fluidized bed space. Outflow from the portion 3b to the outside can be prevented. As a result, there is no problem even if the cleaned high temperature gas (exhaust gas) is circulated stably and over a long period of time. Then, by circulating and using the high-temperature gas (exhaust gas) in this way, the recovery utilization rate of the high-temperature exhaust gas can be maximized, and a heating device with extremely high thermal efficiency can be realized. In addition, since the amount of heat heated by the bottom plate 4 can be minimized, the cost for the heat treatment can be reduced.

  Further, according to the above configuration, the fluidized bed 3 has a double wall structure having the inner wall surface portion 6 and the outer wall surface portion 7, and is discharged from the top of the fluidized bed body 3 a between the inner wall surface portion 6 and the outer wall surface portion 7. Since the circulation passage 8 for guiding the high-temperature gas composed of the exhaust gas to the lower side of the bottom plate 4 is formed, the heating device provided with the fluidized bed 3 can be made extremely compact, and the disposition distance of the circulation passage 8 can be extremely reduced. The loss of hot air conveyance that can be shortened and escape from the circulation passage 8 can be minimized. In addition, since the inner wall surface 3 of the fluidized bed 3 is covered from the outside by the circulation passage 8, it is possible to minimize the leakage of heat from the fluidized bed 3 to the outside, and a heating device with extremely high thermal efficiency. Can be realized.

  Moreover, the workpiece 1 as a heating target is preferably a casting before coating or an amorphous metal part, and when it is a casting before coating, the processing speed in the coating process can be improved. The amorphous metal part can be tempered (quenched / tempered) well, but is not limited to this, and can be applied to various heat treatments of the workpiece 1 made of other metals.

1 Work 2 Powder (Heat medium)
3 Fluidized bed (fluidized bed for heating)
3a Fluidized bed body 3b Fluidized bed space 4 Bottom plate 5 Induction heating coil (induction heating means)
6 inner wall surface portion 7 outer wall surface portion 8 circulation passage 9 blower 10 dust filter 11 electric chain block (conveying means)
13 Outside air introduction blower

Claims (5)

A heating device for heating a metal workpiece,
Using a granular material heated by high-temperature gas as a heat medium, equipped with a fluidized bed in which the workpiece is immersed,
A heating apparatus configured to introduce a high-temperature gas that has passed through the bottom plate into the fluidized bed by using a porous metal that is heated and breathable as a bottom plate of the fluidized bed.   2. The heating apparatus according to claim 1, further comprising induction heating means for induction heating the bottom plate of the fluidized bed.   The heating apparatus according to claim 1, further comprising an energization device that energizes the bottom plate of the fluidized bed to heat the bottom plate. A dust filter and a blower;
The exhaust gas discharged from the fluidized bed is sucked and removed through the dust filter, and then the purified exhaust gas is again supplied to the fluidized bed through the bottom plate of the fluidized bed by the blower, thereby forming the exhaust gas. The heating apparatus according to any one of claims 1 to 3, wherein the high-temperature gas is circulated.   For the circulation of guiding the high temperature gas consisting of the exhaust gas discharged from the top of the fluidized bed between the inner wall surface and the outer wall surface, between the inner wall surface and the outer wall surface. The heating apparatus according to any one of claims 1 to 4, wherein a passage is formed.

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