JPS629812Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a food heating device for heating foods such as donuts and fried bread, and more particularly to a preheating device for preheating donuts and fried bread before frying them.

As a heating furnace for preheating fermented dough made mainly of flour and yeast for doughnuts, fried bread, etc., before frying, a fin heater is installed inside the furnace, and steam is passed through the furnace to generate heat convection. Although it is known that heat treatment is performed using thermal convection, such heating furnaces have the following drawbacks.

(1) Since the heat treatment is based on heat convection, heat transfer is poor and the heating time is long.In order to increase productivity, the length of the furnace inevitably becomes longer, which becomes uneconomical.

(2) Since steam is used as a heat source, temperature control is difficult and the temperature distribution inside the furnace is poor, and the accuracy of temperature control causes chips and uneven baking, resulting in unstable baked quality.

(3) Since the surface is rapidly heated by hot air, it also has a drying effect, which quickly forms a film on the surface and hardens the skin, preventing the dough from expanding and thickening the skin, resulting in poor taste and texture. It can get worse.

The present invention was completed with the aim of providing a food heating device that does not have the above-mentioned drawbacks, and the illustrated embodiment will be described in detail below.

Figures 1 and 2 show an embodiment of the food heating device of the present invention, in which 1 is a heating device equipped with a tunnel furnace-shaped microwave heating means made of a stainless steel plate or the like and installed at one end of the conveyance path. In the furnace, in the furnace on the inlet side 2 and outlet side 3, which correspond to about 1/3 of the furnace length of the heating furnace 1, a copper alloy is placed close to the upper and lower surfaces of the conveying path to prevent microwave leakage. A microwave absorber 4 such as the above is provided, and microwave leakage indicator lights 7 are provided near the entrance 5 and exit 6.

On the other hand, a microwave waveguide duct 9 connected to a microwave oscillator (not shown) installed outside the heating furnace 1 is located in a central portion 8 corresponding to about 1/3 of the furnace length of the heating furnace 1. A microwave irradiation zone is formed in conjunction with a microwave stirring fan (not shown) connected to the ceiling of the heating furnace 1 and mounted on the ceiling inside the furnace. Reference numeral 10 denotes an infrared heating furnace connected to the outlet 6 of the heating furnace 1 on the conveyance path. A large number of infrared radiant electric heaters 11 with electrical resistors embedded in ceramic material are arranged uniformly in opposition to the conveyance path, and between the infrared radiant electric heaters 11 arranged on the ceiling surface of the furnace. , a large number of branch pipes 12 of the air injection device are arranged at approximately the same position as the radiation surface, and each branch pipe 12 has an air injection port 1 for promoting heating of the food transferred on the conveyance path.
3 are arranged facing downward at required intervals.

The branch pipes 12 penetrate the side wall of the heating furnace 10 and extend to a length that is approximately the same as the inner width of the infrared heating furnace 10, and the base end of each branch pipe 12 is connected to a valve connected outside the furnace. It is connected to a high-pressure blower 16 mounted on the infrared heating furnace 10 through a conduit 15 with a pipe 14, which sucks room temperature air and injects it inside the furnace. Further, at the outlet 17 of the infrared heating furnace 10, a flexible plate 18 is provided which can be slid up and down so as to be adjustable according to the thickness of the food.

The heating furnace 1 and the infrared heating furnace 10, which are sequentially arranged on the conveyance path as described above, are installed in series on the conveyance path, and the food A is transferred to the heating furnace 1 using a conveyance device 19 such as a belt conveyor. Inlet 5, outlet 6, inlet 20 of infrared heating furnace 10, and outlet 17
The oil is then preheated, taken out, and transferred to a frying oil tank for the next process.

With this configuration, when the food A to be preheated, such as fried bread, placed on the conveyor 19 is sent into the heating furnace 1 through the inlet 5, a microwave is placed inside the heating furnace 1. The fried bread is heated from inside by dielectric heating due to the penetrating action of the microwave while passing through the heating furnace 1. Therefore, the temperature inside the dough rises rapidly without a film forming on the surface of the dough, thermally expanding the gas inside the dough, and preheating the inside of the dough for frying bread in a short time. .

Next, the fried bread, which has been preheated inside the dough,
At the outlet 6 of the heating furnace 1, it is transferred into the infrared heating furnace 10 from the inlet 20 of the infrared heating furnace 10, which is provided on the same conveyance path. Although there is no osmotic effect, since the infrared radiant electric heater 11 is provided, which absorbs most of the radiant heat on the surface of the object as a heating source for the surface of the object or thin film, the radiant energy from the infrared radiant electric heater 11 is In addition to uniformly drying the surface layer of the fabric, the compressed air flow generated from the high-pressure blower 16 flows through each branch pipe 1.
Injected from the air jet port 13 for heating promotion of No. 2,
The heat convection in the oven is involved and the hot air is sprayed onto the surface of the fried dough, increasing the removal rate of the thermal boundary film on the surface of the dough and rapidly reducing the thermal gradient between the dough surface and the surface layer of the dough. For example, when preheating fried bread by setting the microwave output of the heating furnace 1 to 10KW and the internal temperature of the infrared heating furnace 10 to 120°C, it is possible to heat the surface and surface layer of the dough. Approximately 50 hours
It has been experimentally confirmed that the preheating time can be reduced to approximately 1/3 of the conventional preheating time.

Moreover, the fried bread that has been preheated in a short time using the food heating device of the present invention is heated internally in a heating furnace until it is well-cooked, and then the surface layer is radiantly heated in an infrared heating furnace. Therefore, not only do the surface wrinkles not occur, but the skin is also thin and has such a good quality that the surface after frying rises to a golden brown color, has less deformation, and has a better taste and texture. be.

In addition, as the infrared radiant electric heater 11, it is suitable to use an electric heating resistor such as a nichrome wire embedded inside a ceramic material such as a glazed ceramic board, which can uniformly heat the heater in a short period of time. Not only is it resistant to moisture, it is clean and hygienic. Moreover, it has a large heat capacity and does not cool easily, so the temperature drop rate of the heater itself is slow and the range of fluctuation relative to the set temperature is small, so it can heat evenly.

Although the present invention can be implemented as described above, it is not limited to the embodiments. For example, in the branch pipe 12 for promoting heating, a number of air jet ports 13 are arranged upwardly at required intervals between the infrared radiation electric heaters 11 arranged on the bottom surface, and hot air is ejected onto the upper and lower surfaces of the food. It can also be used as a thing.

As is clear from the explanation of the above embodiments, the food heating device of the present invention first preheats the inside of the dough using microwaves installed in a heating furnace, and then preheats the inside of the dough using microwaves installed in an infrared heating furnace. It is configured to preheat the surface and surface layer of the dough using the radiant heat emitted by the infrared radiant electric heater and the hot air jetted from the heating-enhancing air jet, which greatly reduces the preheating time before frying. The installation area of the equipment can be reduced, and since the skin is deep-fried with no wrinkles and a glossy thin skin, the surface is fried to a golden brown color, and has the advantage of less deformation and improved taste and texture. It is of great practical value as it eliminates the drawbacks of conventional food heating devices of this kind.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway vertical cross-sectional view showing an embodiment of the present invention, and FIG. 2 is a partially cutaway cross-sectional view of a second heating furnace. 1... Heating furnace, 2... Inlet side, 3... Outlet side,
4...Microwave absorber, 5...Inlet, 6...Outlet, 7...Microwave leak indicator light, 8...Central part, 9...Microwave waveguide duct, 10...Infrared heating furnace, 11... ...Infrared electric radiant heater, 12
... Branch pipe, 13 ... Air outlet, 14 ... Valve, 15 ... Conduit, 16 ... High pressure blower, 17
...Exit, 18...Shipping board, 19...Transport device, 20...Entrance, A...Food.

Claims (1)

[Scope of utility model registration request] On the conveyance path of the food heating device, there is a heating furnace 1 equipped with microwave heating means, an infrared radiant electric heater 11 on the inner wall surface, and an infrared radiant electric heater 11 on the inner wall surface.
A food heating device characterized in that an infrared heating furnace 10 is successively divided into a series and provided with a large number of alternating air jet ports 13 for promoting heating adjacent to the infrared heating furnace 10.