Electronic combustion furnace

Abstract: An electronic combustion furnace (3) characterized in that a heating element (1) including carbon powder sealed in an evacuated condition within a heat-proof material (11) is heated to heat and melt an object to be heated and wasted by irradiating microwaves to the heating element (1).

Description: The present invention relates to a microwave combustion furnace using a heating element, more particularly to a microwave combustion furnace for melting an object to be heated by using the heating element generating high temperature by being irradiated with microwaves. Hitherto, there has been widely used a microwave oven for heating an object by utilizing microwaves. The microwave oven, however, has a main purpose for cooking foods such as reheat or thaw, and therefore it is not possible for such a microwave oven to heat, melt and then waste and dispose the object to be heated and wasted, because it has been difficult for the conventional apparatuses to increase the temperature of the object to be heated to the extent that the object is wasted. US-A-4,822,966, which forms the basis for the preamble of claim 1, discloses a microwave furnace in which a microwave energy absorbing medium containing carbon powder is irradiated with microwaves to reach a high temperature. The object of the present invention is to solve the above-mentioned problems in the conventional apparatus, and to present a heating element generating high temperature by being irradiated with a microwave and further a microwave combustion furnace for heating the object to be heated and wasted by utilizing the high temperature generated by the heating element. Accordingly the invention provides a microwave combustion furnace comprising: a receiving portion for receiving objects to be heated; at least one microwave generator; and a plurality of heating elements located in the receiving portion, each heating element including carbon powder , said at least one microwave generator being arranged to irradiate said heating elements within the receiving portion with microwave radiation to raise their temperature for heating the objects, characterized in that the carbon powder of the heating elements is sealed in an evacuated condition within a heat-proof material. One embodiment of the present invention will be explained hereinafter with reference to the attached drawings in which: Fig. 1 is partially broken perspective view showing the entire construction of a microwave combustion furnace using a heating element, as an embodiment of the present invention; Fig. 2 is a perspective view showing the construction of the heating element with high temperature; Fig. 3 is a plan view showing the disposition of a microwave generator mounted in a receiving portion of the microwave combustion furnace; and Figs. 4 and 5 are respectively plan view and side view showing a suction device and an exhaust purifying device mounted on the periphery of the receiving portion. Fig. 1 is a schematic and perspective view showing the entire construction of the microwave furnace 2 for heating and wasting an object to be heated and wasted and a plurality of heating elements 1 used for heating the object, as an embodiment of a microwave combustion furnace of the present invention. Fig. 2 is a perspective view showing a construction of the heating element 1 generating high temperature in which the mixture 12 of a carbon powder and an alumina powder is filled within a quartz tube 11 in a vacuum condition. There are filled quartz wools 13 at both end portions of the quartz tube 11 in order to seal the mixture 12 and both ends of the quartz tube 11 are sealed. The quartz tube 11 may have a diameter of about 8 mm and a length of about 100 mm. If the microwave having high frequency about 2450 MHz ordinary used for an electronic range or the like is irradiated to the heating element 1, the carbon powder is mainly heated due to a dielectric heating function till a high temperature. By adjusting a mixture ratio of the carbon powder and the alumina powder, it is possible to adjust the generated temperature within a range from about 30°C to about 1600°C. Here, the melting temperature of the quartz tube is about 1200°C. As mentioned above, the temperature of the heating element is changed in accordance with the mixture ratio, and the following table shows the experiment results showing the relationship between the lapse time in which the mixture 12 with about 30 g, is heated to the temperature within the range from about 600°C to about 700°C and the mixture ratio (volume ratio). 1 min. 1 min.10sec 1 min.30 sec 2 min. 2 min. Carbon 2 1.5 1.2 1 0.5 Alumina 0 0.5 0.8 1 1.5 As is apparent from the above table, if there is no alumina powder, the heating element reaches to the above high temperature 600°C - 700°C only one minute, but as the alumina powder is increased the time required to reach the predetermined temperature is also increased. This means that the alumina powder functions to restrict an abrupt increment of temperature of the heating element and to retain the high temperature of the heating element. Furthermore, if the amount of the alumina powder is increased rather than the amount of the carbon powder, not only there is obtained a later increasing speed in temperature but also the obtained temperature may be restricted to about 400°C to 500°C. The construction of the combustion furnace 2 is mainly composed of a box type receiving portion 3 for receiving an object to be heated, twelve heating elements 1 disposed on the bottom of the receiving portion 3, a microwave generator 4 (Fig. 3) such as a magnetron, a suction device 5 for sucking a gas such as carbon oxide generated during the combustion by utilizing a vacuum pump (not shown), an exhaust gas purifying device 6 composed of a microwave generator 61 and a heating element 62 with high temperature, disposed in a suction path of the suction device 5, a dropping mechanism 7 for dropping dregs (not shown) in the receiving portion 3 downwardly, and a smashing mechanism 8 for smashing the dropped dregs by utilizing gears. The inner wall of the receiving portion 3 is composed of such as stainless steel and its bottom portion thereof is composed of two doors 31 and 32 which are rotatable around the shafts 33 and 34 respectively as shown by arrows A and B. The shafts 33 and 34 are fixed with gears 35 and 36 and the respective gears 35 and 36 are connected to each other by a chain 37. If a handle 38 fixed on the shaft 34 is rotated in the counterclockwise direction against the resilient force of a spring 39, the doors 31 and 32 are rotated in the direction shown by arrows A and B respectively thereby dropping the stacked dregs (not shown) on the bottom portion of the receiving portion. The bottom surface of the receiving portion is mounted with a heat-resisting material such as asbestos, and the plural heating elements are fixed on the heat-resisting material by using a heat-resisting adhesive. There are disposed magnetron generators 4A and 4B as an energy source for heating the heating elements with high temperature, as shown in Fig. 3. According to a normal microwave oven, a single magnetron generator is mounted, and if two or more number of the magnetron generators are used in the microwave oven, it was very difficult to dispose the plural magnetron generator suitably not to produce any interference between the plural magnetron generators. According to the present invention, the plural magnetron generators are disposed as shown in Fig. 3, in such a manner that the axes of the waveguide tubes 41 and 42 respectively connected to the output side of the magnetron generators 4A and 4B are crossed with an angle . This angle  may be set smaller than 90°. the magnetron generator 4 may irradiate the microwave having the frequency 2450 MHz generally used for the usual electronic range. As an electric source for driving the generator 4, a usual one used for the usual electronic range, and its explanation is omitted herewith. The smoke such as carbon oxide, steam or the like generated within the combustion furnace is sucked to a duct 52 from a smoke inlet 51 mounted at the side wall of the receiving portion 3 by using a vacuum pump (not shown). The smoke sucked from the smoke inlet 51 into the duct 52 is further burned by a heating element 62 driven by the magnetron generator 61 of the exhaust gas purifying device 6, and as a result the smoke is purified and emitted to external. Thus, the sucked smoke is heated with high temperature of about 700°C, and therefore gas such as carbon monoxide is oxidized to become harmless gas (carbon dioxide) and further germs are sterilized. The dropped dregs are smashed by the rotation of the roller gears 81 and 82 of the smashing mechanism 8. Since the shaft of one gear 82 is supported within the bearing formed as an elongated hole, it is possible to prevent the roller gears 81 and 82 from destruction by shifting the shaft in the elongated hole, even if the material which is difficult to smash by the roller gears is inserted therebetween. The roller gears 81 and 82 are driven by a driving motor 9. The operation temperature of the heating element with high temperature can be controlled in a well-known manner by using a temperature sensor (not shown). The formation of the heating element may be of a circular or a plate-like formation. Moreover, it is possible to disperse at least carbon powder or the mixture of carbon powder and alumina powder within such as aquartzmaterial. It is also possible to form the heating element in a dish or a pan-like formation. Moreover, it is also possible to provide more than two microwave generators. As mentioned above, according to the present invention high temperature is easily and quickly obtained by utilizing a heating element with high temperature generated due to the irradiation of microwave. Therefore, 5 a wasted gauze, a surgical operation wares made of paper, bandages, a wasted injection needle, a filter used for artificial kidney dialysis, and extracted organs due to a surgical operation, which are wasted from medical facilities (hospital etc.); and a raw kitchen waste can be easily burnt.

Claims: A microwave combustion furnace (2) comprising: a receiving portion (3) for receiving objects to be heated; at least one microwave generator (4); and a plurality of heating elements (1) located in the receiving portion (3), each heating element (1) including carbon powder (12) , said at least one microwave generator (4) being arranged to irradiate said heating elements (1) within the receiving portion (3) with microwave radiation to raise their temperature for heating the objects, characterized in that the carbon powder of the heating elements (1) is sealed in an evacuated condition within a heat-proof material (11). A furnace according to claim 1, further comprising: at least one additional heating element (62) including carbon powder (12) sealed in an evacuated condition within a heat-proof material (11); and a microwave generator (61) for irradiating the or each additional heating element to raise its or their temperature, wherein the or each additional heating element (62) for purifying smoke and/or gas emitted by said objects is located in a duct (52) in communication with said receiving portion (3) via a smoke inlet (51). A furnace according to claim 2, further comprising a suction device for sucking smoke and/or gas from said receiving portion (3) into said duct (52). A furnace according to any one of the preceding claims, wherein said heating elements (1, 62) further contain alumina powder in addition to the carbon powder. A furnace according to any one of the preceding claims wherein said heat-proof material comprises a quartz tube (11). A furnace according to claim 5, further comprising quartz wool (13) at both ends of said quartz tube. A furnace according to any one of the preceding claims, further comprising doors (31, 32) in the bottom of the receiving portion (3) for dropping the remains of the heated objects. A furnace according to claim 7 wherein said plurality of heating elements (1) are mounted on the doors (31, 32). A furnace according to any one of the preceding claims, further comprising a smashing mechanism for smashing the remains of the heated objects.

Inventors: NARA AKIKAZU, NARA, AKIKAZU
Applicants: NARA SEIKI KK, NARASEIKI KABUSHIKI KAISHA
Application year: 1991
Main classification: H05B6
IPC codes: H05B6, F23G5