Cooker

Abstract

Provided is a cooker which comprises a heat source 2 that comprises a gas burner or the like and a metal heat plate 3 that is disposed above the heat source 2, and which makes it possible to sufficiently improve the heating efficiency of an item to be cooked with heat from the heat source 2 and to suppress heating of the heat source 2.　A high-emissivity coating film 3a for increasing far-infrared emissivity is formed on an upper surface of the heat plate 3, and also a high-emissivity coating film 3b is formed on a lower surface of the heat plate 3. Increasing the emissivity (= absorptivity) of the lower surface of the heat plate 3 suppresses heating of the heat source 2 by reflected heat from the lower surface of the heat plate 3 and further allows radiant heat from the heat source 2 to be efficiently absorbed by the lower surface of the heat plate 3, thereby improving the heating efficiency of the item to be cooked.

Description

Grilling equipment

[0001] The present invention relates to a roasting cooker.

[0002] Conventionally, a grill cooker has been known which includes a heat source and a metal heating plate placed above the heat source, and which heats food placed above the heating plate with far infrared rays radiated from the heating plate (see, for example, Patent Documents 1 and 2).

[0003] Also, Patent Document 3 discloses a grill in which the lower surface of a hot plate placed below the upper burner is black-painted to increase the emissivity of far-infrared rays toward food placed below the hot plate. This technology can be applied to the above-mentioned grill cooker by black-painting the upper surface of the hot plate placed above the heat source to increase the emissivity of far-infrared rays toward food placed above the hot plate.

[0004] However, simply applying a black coating to the upper surface of the hot plate causes radiant heat from the heat source to be reflected back toward the heat source by the lower surface of the hot plate. This prevents sufficient improvement in the heating efficiency of the food being cooked. Furthermore, the heat reflected from the hot plate heats the heat source, adversely affecting its durability. Furthermore, if the heat source is a gas burner and the fuel gas is a gas with a high combustion rate (e.g., hydrogen gas), the reflected heat from the hot plate may cause backfire.

[0005] JP 10-179418 A JP 2023-46513 A JP 2012-200302 A

[0006] In view of the above, the present invention aims to provide a grill cooker that sufficiently improves the heating efficiency of the food being cooked using heat from the heat source while also suppressing heating of the heat source.

[0007] In order to solve the above problem, the present invention provides a grill cooker comprising a heat source and a metal hot plate arranged above the heat source, characterized in that a high-emissivity coating film is formed on both the top and bottom surfaces of the hot plate.

[0008] According to the present invention, the emissivity of the lower surface of the hot plate is increased and the reflectivity is decreased, so that the heating of the heat source by the reflected heat from the hot plate can be suppressed. In addition, since the emissivity and the absorptivity are equal, the higher the emissivity of the lower surface of the hot plate, the higher the absorptivity. Therefore, the radiant heat from the heat source is efficiently absorbed by the lower surface of the hot plate. In addition, in combination with the higher emissivity of the upper surface of the hot plate, the heating efficiency of the food to be cooked by the heat from the heat source can be sufficiently improved.

[0009] In addition, in the present invention, when the heat source is a gas burner, the coating film on the lower surface of the hot plate is preferably a coating film with high emissivity in the wavelength range including the emission wavelength of the combustion flame of the gas burner, and the coating film on the upper surface of the hot plate is preferably a coating film with high emissivity in the wavelength range of far-infrared rays, specifically, a coating film with an emissivity of 0.9 or more in the wavelength range of 3000 nm or more. This improves the emissivity of far-infrared rays from the upper surface of the hot plate and also improves the absorption rate of radiant heat from the combustion flame on the lower surface of the hot plate, thereby maximizing the heating efficiency of the heated object. In addition, heating of the gas burner by reflected heat from the hot plate is effectively suppressed. This also helps prevent flashback, which is likely to occur when the fuel gas is a gas with a fast combustion rate.

[0010] When the fuel gas is hydrogen gas, the coating film on the lower surface of the hot plate should have a high emissivity in the wavelength range of 900-1000 nm, which includes the emission wavelength of the combustion flame of hydrogen gas, that is, about 930 nm, specifically, a coating film with an emissivity of 0.9 or more in the wavelength range of 900-1000 nm.

[0011] The present invention will be described in detail below with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a cooking device according to an embodiment of the present invention; Fig. 2 is a cross-sectional side view taken along line II-II in Fig. 1; Fig. 3 is a cross-sectional front view taken along line III-III in Fig. 2; Fig. 4 is a perspective view of a burner unit including a gas burner provided in the cooking device according to the embodiment;

[0012] 1 to 3 , the grill cooker of this embodiment of the present invention has two orthogonal horizontal directions, the X-axis and the Y-axis, and a plurality of (specifically, four) burner units B arranged in parallel in the Y-axis direction at the top of an open-topped cooker body 1. The burner units B include a gas burner 2 serving as a heat source, elongated in the X-axis direction, and a metal hot plate 3 arranged above the gas burner 2 and having an upwardly convex cross section (specifically, an upwardly convex arc shape). The hot plate 3 has a plurality of vent holes 31 formed by cutting and raising, through which combustion gas generated by combustion in the gas burners 2 passes. The hot plate 3 is heated to red heat by the combustion in the gas burners 2. Food to be cooked on a grill 4 arranged above the cooker body 1 is heated by far infrared rays radiated from the hot plate 3 and the combustion gas passing through the vent holes 31.

[0013] Grilling net 4 is placed on a rectangular support frame 42 connected to the upper ends of liftable support posts 41 provided on both sides of the appliance 1 in the Y-axis direction. Support posts 41 are raised and lowered by the vertical swing of an operating lever 43 protruding in one direction of the appliance 1 in the X-axis direction. A lock lever 44 is attached to operating lever 43, which locks it in any swing position. Pulling lock lever 44 upward to release the lock allows swinging of operating lever 43. In addition, a drip tray 5 is located at the bottom of appliance 1 so that it can be removed in one direction of the X-axis.

[0014] The gas burner 2 comprises a tubular burner body 21 elongated in the X-axis direction, with a plurality of upwardly opening flame holes 22 formed along the X-axis direction at the top of the burner body 21. In this embodiment, two adjacent rows of flame holes, each consisting of a plurality of flame holes 22 along the X-axis direction, are provided in the Y-axis direction. Both ends of the burner body 21 in the X-axis direction are closed by plugs 23, 23. Referring to FIG. 4 , each plug 23 has a protrusion 231 protruding outward in the X-axis direction. The protrusion 231 of each plug 23 is fastened to support brackets 12 for the burner unit B, which are fixed to the frames 11 on both sides of the upper portion of the body 1 in the X-axis direction. This secures and supports the gas burner 2. Each support bracket 12 also supports each end of the hot plate 3 in the X-axis direction. The gas burner 2 is also provided with an ignition electrode 24 serving as ignition means located above one end in the X-axis direction and a thermocouple 25 serving as flame detection means located above the other end in the X-axis direction.

[0015] Each gas burner 2 is supplied with hydrogen gas as fuel gas via a connection path 61 extending from each valve unit 6 in a box 13 attached to one surface of the body 1 in the X-axis direction, and this hydrogen gas is ejected from the flame holes 22 of the gas burner 2 and undergoes diffusion combustion. On one outer surface of the box 13 in the X-axis direction, there are arranged an operation knob 62 for each valve unit 6 and a power switch 63 for starting a controller (not shown) for each valve unit 6. When the operation knob 62 is pressed and turned from its rest position to perform the ignition operation, hydrogen gas is supplied to the gas burner 2 and a spark is generated at the ignition electrode 24, igniting the gas burner 2.

[0016] Furthermore, a partition plate 7 is erected between adjacent burner units B in the Y-axis direction. Even if oil or grease dripping from the food being cooked splashes onto the hot plate 3 of each burner unit B or falls along the hot plate 3, the partition plate 7 prevents the oil or grease from adhering to the flame holes 22 of the gas burners 2 of the adjacent burner unit B. The partition plate 7 is supported by inserting the lower ends of both ends in the X-axis direction into slits (not shown) formed in each frame 11 on both sides in the X-axis direction at the top of the appliance body 1. Another partition plate 7 is erected outside the Y-axis direction of the outermost burner unit B in the Y-axis direction.

[0017] In this embodiment, high-emissivity coatings 3a, 3b are formed on both the top and bottom surfaces of the hot plate 3 (see FIG. 3). This increases the emissivity of the bottom surface of the hot plate 3 and decreases the reflectivity, thereby suppressing the heating of the gas burner 2 by the heat reflected from the hot plate 3. Therefore, even if the fuel gas is hydrogen gas, which has a fast combustion rate, backfire caused by the heat reflected from the hot plate 3 can be prevented. Furthermore, since Kirchhoff's law equates emissivity and absorptivity, increasing the emissivity of the bottom surface of the hot plate 3 also increases absorptivity. Therefore, the radiant heat from the combustion flame of the gas burner 2 is efficiently absorbed by the bottom surface of the hot plate 3. This, combined with the increased emissivity of the top surface of the hot plate 3, significantly improves the heating efficiency of the food being cooked by the heat from the gas burner 2.

[0018] Here, the coating film 3a on the upper surface of the hot plate 3 is preferably a coating film with high emissivity in the wavelength range of 3000 nm or more, which is the far-infrared ray, specifically, a coating film with an emissivity of 0.9 or more in the wavelength range of 3000 nm or more, and the coating film 3b on the lower surface of the hot plate 3 is preferably a coating film with high emissivity in the wavelength range of 900-1000 nm, which is the wavelength range including the emission wavelength of the combustion flame, i.e., the wavelength range including the emission wavelength of the hydrogen gas combustion flame of about 930 nm, specifically, a coating film with an emissivity of 0.9 or more in the wavelength range of 900-1000 nm. This improves the emissivity of far-infrared rays from the upper surface of the hot plate 3 and also improves the absorption rate of radiant heat from the combustion flame on the lower surface of the hot plate 3, thereby improving the heating efficiency of the heated object as much as possible. An example of a paint that forms a coating film with an emissivity of 0.9 or more at wavelengths of 3000 nm or more is a far-infrared ceramic paint, and an example of a paint that forms a coating film with an emissivity of 0.9 or more at wavelengths of 900-1000 nm is a carbon black paint.

[0019] Although the embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited thereto. For example, in the above embodiment, a grill 4 on which food to be cooked is placed is disposed above the hot plate 3. However, rod-shaped members extending in the Y-axis direction may be provided on both sides of the top surface of the appliance body 1 in the X-axis direction, so that skewers inserted into food to be cooked can be placed across both rod-shaped members. Also, while the heat source in the above embodiment is a gas burner 2, the present invention can be similarly applied to a grill cooker that uses a heat source other than a gas burner 2, such as an electric heater.

[0020] 2...gas burner, 3...hot plate, 3a...coating film on the upper surface of the hot plate, 3b...coating film on the lower surface of the hot plate.

Claims

1. A grilling cooker comprising a heat source and a metal hot plate placed above the heat source, characterized in that a high-emissivity coating is formed on both the top and bottom surfaces of the hot plate.

2. A grill cooker as described in claim 1, wherein the heat source is a gas burner, characterized in that the coating on the underside of the hot plate is a coating with a high emissivity in a wavelength range that includes the emission wavelength of the combustion flame of the gas burner, and the coating on the upper surface of the hot plate is a coating with a high emissivity in the wavelength range of far-infrared rays.

3. A grilling cooker according to claim 2, wherein the coating on the upper surface of the hot plate has an emissivity of 0.9 or more in the wavelength range of 3000 nm or more.

4. A grill cooker according to claim 2 or 3, wherein the fuel gas supplied to the gas burner is hydrogen gas, and the coating on the underside of the heating plate is a coating with high emissivity in the wavelength range of 900-1000 nm.

5. A grill according to claim 4, wherein the coating on the lower surface of the hot plate has an emissivity of 0.9 or more in the wavelength range of 900-1000 nm.

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