Combustion Apparatus

The present invention generally relates to combustion apparatuses and more particularly, to a combustion apparatus including a combustion apparatus housing having an opening formed at a front portion thereof, a combustion tube provided in the opening, and a top plate provided above the combustion tube.

Conventionally, in combustion-apparatus of the above described type, it has been so arranged that heating is performed through utilization of combustion gas and radiant heat emitted from the combustion tube in the opening formed at the front portion of the combustion apparatus housing. However, in the prior art combustion apparatus, as shown in FIG. 1, the high-temperature combustion gas discharged from a combustion tube 31 initially ascends vertically therefrom and then, comes into contact with a top plate 32 so as to be carried forwardly of the top plate 32 as indicated by the arrow H. Accordingly, in the known combustion apparatus, there is such a danger that since the temperature of the top plate 32 rises extremely, the user gets burnt through inadvertent touching with the heated top plate 32.

In order to lessen the danger referred to above, there has been proposed a combustion apparatus in which a heat shielding plate 33 is provided below the top plate 32 as shown in the one-dot chain lines in FIG. 1 so as to prevent the temperature of the top plate 32 from rising exceedingly. However, even in this known combustion apparatus, such a disadvantage still exists that since the combustion gas flowing out of a front end 32a of the top plate 32 heats the front end 32a, the user gets burned by the heated front end 32a. Furthermore, in the prior art combustion apparatus, there is the inconvenience that since air trapped in a space T defined between the top plate 32 and the heat shielding plate 33 is gradually heated to a high temperature when the prior art combustion apparatus is used continuously for a long time, the top plate 32 is also heated to a high temperature with the result that the user gets burnt by the heated top plate 32.

Accordingly, an essential object of the present invention is to provide an improved combustion apparatus including a combustion apparatus housing having an opening formed at a front portion thereof, a combustion tube provided in the opening, and a top plate provided above the combustion tube, in which the top plate as a whole is maintained at a low temperature even after the combustion apparatus has been used continuously for a long time so as to obviate such a danger that the user gets burnt through inadvertent touching with the heated top plate, with substantial elimination of the disadvantages inherent in conventional combustion apparatus of this kind.

In order to achieve the above described object, in the combustion apparatus according to the present invention, at least one heat shielding plate is provided below the top plate so as to define a gap therebetween such that the gap acts as an air passage. Furthermore, it is so arranged that a front end of the heat shielding plate is projected forwardly of the top plate so as to prevent combustion gas from coming into direct contact with a front end of the top plate and air is caused to flow through the gap between the heat shielding plate and the top plate.

These and other objects and features of the present invention will become apparent from the following description taken in conjunction with the preferred embodiment thereof with reference to the accompanying drawings, in which:

FIG. 1 is a vertical sectional view of a prior art combustion apparatus (already referred to);

FIG. 2 is a perspective view of a combustion apparatus according to a first embodiment of the present invention;

FIG. 3 is a vertical sectional view of the combustion apparatus of FIG. 2;

FIG. 4 is a view similar to FIG. 3, particularly showing a combustion apparatus according to a second embodiment of the present invention;

FIG. 5 is a partially cutaway front elevational view of a combustion apparatus according to a third embodiment of the present invention;

FIG. 6 is a view similar to FIG. 4, particularly showing a combustion apparatus according to a fourth embodiment of the present invention;

FIG. 7 is a view similar to FIG. 2, particularly showing a combustion apparatus according to a fifth embodiment of the present invention;

FIG. 8 is a view similar to FIG. 7, with a top plate employed therein being removed; and

FIG. 9 is a vertical sectional view of the combustion apparatus of FIG. 7.

Before the description of the present invention proceeds, it is to be noted that like parts are designated by like reference numerals throughout several views of the accompanying drawings.

Referring now to the drawings, there is shown in FIGS. 2 and 3, a combustion apparatus K1 according to a first embodiment of the present invention. The combustion apparatus K1 is a kerosene heater in this embodiment and generally includes a combustion apparatus housing 1 having an opening formed at a front portion thereof, and a lower reflector 2 dividing the opening into an upper space 12 and a lower space 7. The housing 1 includes a rear plate 1a for covering a rear face of the housing 1, a top plate 14 for covering an upper face of the housing 1, a base plate 4 attached to a lower face of the housing 1 and a front plate 5 for covering a lower front face of the housing 1. Namely, the upper space 12 opens forwardly but the lower space 7 is covered by the front plate 5. The combustion apparatus K1 further includes a fuel tank 6 provided in the lower space 7 disposed below the lower reflector 2, and a wick 8 for sucking up and vaporizing fuel in the fuel tank 6, with the wick 8 being vertically movably provided. Meanwhile, the rear plate 1a has a plurality of holes 3 formed above the lower reflector 2.

The combustion apparatus K further includes a wick raising knob 9 for raising and lowering the wick 8, an ignition mechanism 10 for igniting the wick 8, a combustion tube 11 for burning the vaporized fuel from the wick 8, and a side reflector 13 surrounding rear peripheral portions of the combustion tube 11. The combustion tube 11 is inserted, at a lower portion thereof, through the lower reflector 2 so as to be placed on an upper portion of the fuel tank 6 such that an upper portion of the combustion tube 11 projects into the upper space 12. The side reflector 13 is intended to reflect forwardly of the housing 1 radiant heat from the combustion tube 11 and a gap T is defined between the side reflector 13 and the rear plate 1a.

Furthermore, the combustion apparatus K1 includes first, second and third heat shielding plates 15, 16 and 17. The first heat shielding plate 15 is attached to an upper portion of the side reflector 13 and is disposed below the top plate 14 so as to define a gap therebetween such that a front end of the first shielding plate 15 projects forwardly of the top plate 14. The second and third heat shielding plates 16 and 17 are disposed between the first heat shielding plate 15 and the top plate 14 so as to confront the first heat shielding plate 15 and the top plate 14, respectively such that first, second and third gaps T1, T2 and T3 acting as air passages are, respectively defined between the first and second heat shielding plates 15 and 16, between the second and third heat shielding plates 16 and 17 and between the third heat shielding plate 17 and the top plate 14. It is to be noted that front ends of the second and third heat shielding plates 16 and 17 are also so provided as to project forwardly of the top plate 14 as in the case of the first heat shielding plate 15. It is so arranged that the front ends of the third, second and first heat shielding plates 17, 16 and 15 are gradually further projected forwardly of the top plate 14 in this order such that the front end of the first heat shielding plate 15 disposed most adjacent to the combustion tube 11 is projected furthest forwardly of the top plate 14 and the first, second and third heat shielding plates 15, 16 and 17 are inclined obliquely upwardly toward the front ends of the first, second and third heat shielding plates 15, 16 and 17, respectively.

Meanwhile, the first gap T1 between the first and second heat shielding plates 15 and 16, the second gap T2 between the second and third heat shielding plates 16 and 17 and the third gap T3 between the third heat shielding plate 17 and the top plate 14 are communicated with the gap T between the side reflector 13 and the rear plate 1a so as to function as the air passages. The second heat shielding plate 16 is formed, at a rear end thereof, with a bent portion 16a projecting downwardly into the gap T.

By the above described arrangement of the combustion apparatus K1, when kerosene is filled into the fuel tank 6 and then, the wick 8 is ignited after the wick 8 has been raised by rotating the wick raising knob 9, combustion of the kerosene is started in the combustion apparatus K1, so that radiant heat is emitted from the combustion tube 11 so as to be reflected forwardly of the housing 1 by the side reflector 13 disposed rearwardly of the combustion tube 11 such that radiant heating is effected. Meanwhile, high-temperature combustion gas discharged from the combustion tube 11 ascends vertically and then, comes into contact with the first heat shielding plate 15 so as to flow forwardly out of the first heat shielding plate 15 along the first heat shielding plate 15 as shown by the arrow A in FIG. 3. Since the front end of the first heat shielding plate 15 is projected forwardly of the top plate 14, the high-temperature combustion gas is prevented from coming into contact with a front end 14a of the top plate 14 and thus, it becomes possible to maintain the top plate 14 at a low temperature. Moreover, in this embodiment, since the first, second and third heat shielding plates 15, 16 and 17 are inclined obliquely upwardly toward the front ends of the first, second and third heat shielding plates 15, 16 and 17, respectively, the high-temperature combustion gas flows vigorously forwardly so as to proceed further away from the front end 14a of the top plate 14, thereby effectively preventing the top plate 14 from being heated to a high temperature by the combustion gas.

On the other hand, while the combustion gas flows forwardly along the first heat shielding plate 15 after having come into contact worth the first heat shielding plate 15 as described above, the first heat shielding plate 15 and air in the first, second and third gaps T1, T2 and T3 disposed above the first heat shielding plate 15 are heated, so that a phenomenon of convection takes place and thus, air flows into the gap T through the holes 3 as shown by the arrow B in FIG. 3 so as to pass through the first, second and third gaps T1, T2 and T3 forwardly. Since there is a large difference in temperature between heated air in the first, second and third gaps T1, T2 and T3 and air drawn into the gap T, the convection is of rather high flow velocity. Accordingly, since the first, second and third heat shielding plates 15, 16 and 17 and the top plate 14 are at all times brought into contact with cold air so as to be cooled by the cold air, the top plate 14 is at all times maintained at a low temperature even after the combustion apparatus K1 has been operated for a long time. Furthermore, since the second and third heat shielding plates 16 and 17 are further provided between the top plate 14 and the first heat shielding plate 15, radiant heat from the first heat shielding plate 15 heated by the combustion gas discharged from the combustion tube 11 is shielded by the second and third heat shielding plates 16 and 17. In addition, since the second and third heat shielding plates 16 and 17 are at all times cooled by the convected air, the second and third heat shielding plates 16 and 17 do not act as a secondary radiant source and thus, the top plate 14 is maintained at a lower temperature. Since the above described convected air flows through the gap T between the rear plate 1a and the side reflector 13 via the holes 3 of the rear plate 1a, it becomes also possible to lower temperature of a rear portion of the housing 1. Moreover, since the second heat shielding plate 16 is formed, at its rear end, with the bent portion 16a projecting downwardly into the gap T between the side reflector 13 and the rear plate 1a, the amount of air flowing through the first gap T1 between the first and second heat shielding plates 15 and 16 can be increased by widening a gap T4 between the bent portion 16a and the side reflector 13 so as to further lower temperature of the top plate 14.

Referring to FIG. 4, there is shown a combustion apparatus K2 according to a second embodiment of the present invention, in which convected air is drawn from the lower space 7 for the fuel tank 6. Namely, in the combustion apparatus K2, a hole 18 for passing air therethrough is formed at a rear portion of the lower reflector 2 so as to communicate the gap T and the lower space 7 and only the first and second heat shielding plates 15 and 16 are provided. By this arrangement of the combustion apparatus K2, the convected air is caused to flow into the lower space 7 via an opening 5a of the front plate 5 as shown by the arrow D and then, is introduced into the space T through the hole 18 as shown by the arrow E. Accordingly, the combustion apparatus K2 achieves the same effects as those of the combustion apparatus K1 and further has such an advantage that since the fuel tank 6 is cooled by the air flowing through the lower space 7, the fuel tank 6 is prevented from being heated to a high temperature.

Referring to FIG. 5, there is shown a combustion apparatus K3 according to a third embodiment of the present invention, in which the convected air is drawn also from still another portion. Namely, the combustion apparatus K3 includes the first, second and third heat shielding plates 15, 16 and 17, a movable tank 19 for replenishing the fuel tank 6 with the fuel and a partition plate 20 disposed adjacent to one side plate 1b formed with holes 22 and 23. A space 21 is defined between the partition plate 20 and the side plate 1b such that the movable tank 19 is detachably fitted into the space 21. The space 21 is further communicated with the first, second and third gaps T1, T2 and T3 which are disposed between the first heat shielding plate 15 and the top plate 14. Accordingly, in the combustion apparatus K3, since the convected air is caused to flow as shown by the arrow F, such an advantage can be obtained that the side plate 1b and the movable tank 19 also can be cooled.

In FIG. 6, a combustion apparatus K4 according to a fourth embodiment of the present invention is shown. In the combustion apparatus K4 including the first and second heat shielding plates 15 and 16, the side reflector 13 is formed, at a lower portion thereof, with a hole 24 and a guide plate 25 is attached to a rear face of the side reflector 13 such that a portion of air flowing into the gap T through the hole 3 of the rear plate 3 and the hole 18 of the lower reflector 2 is guided by the guide plate 25 toward the combustion tube 11 via the hole 24. By the above described arrangement of the combustion apparatus K4, since air is caused to flow also below first the heat shielding plate 15 as shown by the arrow G so as to lower temperature of the combustion gas discharged from the combustion tube 11, the top plate 14 is more positively prevented from being heated to a high temperature.

Referring further to FIGS. 7 to 9, there is shown a combustion apparatus K5 according to a fifth embodiment of the present invention, in which opposite side portions 14a of the top plate 14 are more securely prevented from being heated to a high temperature. The combustion apparatus K5 includes the first and second heat shielding plates 15 and 16, a pair of exhaust guides 26 secured to opposite side portions of a lower face of the first heat shielding plate 15, and two pairs of flow regulating plates 27 one pair of which are secured, between the first and second heat shielding plates 15 and 16, to opposite side portions of an upper face of the first heat shielding plate 15, with the other pair of the flow regulating plates 27 being secured, between the second heat shielding plate 16 and the top plate 14, to opposite side portions of an upper face of the second heat shielding plate 16. By this arrangement of the combustion apparatus K5, combustion gas, which ascends from the combustion tube 11 and then, proceeds forwardly along the first heat shielding plate 15 after having come into contact with the first heat shielding plate 15, is prevented by the exhaust guides 26 from being diffused, at the front end of the first heat shielding plate 15, toward left and right side portions of the first heat shielding plate 15 in FIG. 7. Thus, since the combustion gas is prevented from coming into contact with the opposite side portions 14a of the top plate 14 and opposite upper side portions 13a of the side reflector 13, the top plate 14 can be maintained at a still lower temperature. Furthermore, since the flow regulating plates 27 are provided between the first and second heat shielding plates 15 and 16 and between the second heat shielding plate 16 and the top plate 14, the convected air flowing into the gaps T1 and T2 is also prevented by the flow regulating plates 27 from being diffused, at the front ends of the first and second heat shielding plates 15 and 16 and the top plate 14, towards left and right portions of the first and second heat shielding plates 15 and 16 and the top plate 14 and thus, is caused to flow forwardly smoothly, so that it becomes possible to further lower temperature of the top plate 14.

As is clear from the foregoing description, in accordance with the present invention, since not only the central portion but also the front end portion of the top plate, namely the whole top plate can be positively prevented from being heated to a high temperature, it becomes possible to obtain a remarkably safe combustion apparatus.

Furthermore, in accordance with the present invention, even if the combustion apparatus is continuously operated for a long time, the top plate is maintained at a low temperature, thereby ensuring great safety of operation of the combustion apparatus.

Although the present invention has been fully described by way of example with reference to the accompanying drawings, it is to be noted here that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention, they should be construed as being included therein.