JPS63160569A - Apparatus for roasting coffee bean - Google Patents

Abstract

PURPOSE:To provide a roasting apparatus enabling uniform roasting of coffee beans preventing uneven roasting, by using a cylindrical rotary drum having a number of perforations on the circumferential wall, placing the drum nearly horizontally in an oven and providing a number of infrared heaters around and at the center of the rotary drum. CONSTITUTION:A rotary drum 6 having nearly cylindrical form and having a number of perforations bored through the circumferential wall is rotatably supported in horizontal state nearly at the center of an oven 1 composed of a heat-insulation wall. A number of infrared heaters 23 are attached to the surface of the inner wall of the oven 1 in a manner surrounding the rotary drum 6. In addition to the above, an infrared heater 15 is placed at the center of the rotary drum 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a roasting apparatus that can produce high quality roasted coffee beans.

[Prior art and problems] In general, when roasting green coffee beans, various conditions must be set, such as the quality of the green beans themselves, the roasting method, and the ambient temperature and time during roasting. Of these,
In particular, the heat source that generates the roasting temperature has a subtle effect on changes in quality.

Conventionally, roasting was done using a direct flame or high-temperature hot air as the heat source inside the furnace, but with the former method, it was difficult to control the roasting temperature, and it was possible that only the outer surface of the roasted beans would get burnt. The latter method has the disadvantage that it is easy to roast the coffee beans, resulting in uneven roasting.Although the latter method can provide a uniform temperature to the coffee beans compared to the direct flame method, it requires a large amount of hot air and a relatively long time. Coupled with this, the change in the components of green coffee beans due to heating is not optimal, and this method has the drawback that only a flavorful product can be obtained, which tends to occur in the production of large grains.

[Object of the Invention and Means for Solving the Problems] The present invention solves the above-mentioned conventional drawbacks, eliminates uneven roasting, and achieves uniform roasting with a unique aroma.

The purpose is to produce very high quality roasted coffee beans with a moderate taste and brown color.To achieve this purpose, a furnace body is formed with an insulating wall, and a large number of peripheral walls are installed in the center of the interior. A generally cylindrical rotating drum with small holes is supported so as to rotate like a water wheel, an infrared heater is arranged on the wall surface of the furnace body so as to surround the rotating drum, and an infrared heater is arranged in the center of the rotating drum. It consists of a configuration with a

[Operation] With current flowing through the infrared heater to raise the inside of the furnace to a predetermined temperature and rotating the rotary drum at a low speed, pour an appropriate amount of green coffee beans into the rotary drum from the input gutter inserted into the opening/closing door. The green coffee beans are roasted by irradiating the green coffee beans with infrared rays from inside and outside over an appropriate period of time using a plurality of infrared heaters arranged to surround the rotating drum and an infrared heater provided inside the inner cylinder.

[Example] In the figure, ■ indicates front/rear, upper/lower, left/right side walls 2
a ・2 b r 2 c ・2 d + 2 e
- 2 f is a box-shaped furnace body using a heat insulating material, and an opening 3 is provided approximately in the center of the front side wall 2a, and the tip thereof faces into the rotating drum 6, which will be described later. An opening/closing door 5 inserted through the input gutter 4 is attached.

Reference numeral 6 denotes a rotating drum installed at the center of the furnace body l to receive green coffee beans, and has a front end surface 6a open and a rear end surface closed by a contact plate 6b, and a peripheral wall 6c extending along the rear end surface side. It has a generally cylindrical shape with a slightly smaller diameter. Further, many small holes 7 are bored in the peripheral wall 6c, and furthermore, the peripheral wall 6c is
A plurality of baffle plates 8 are spirally protruded from the inner surface of the coffee beans for stirring the green coffee beans well. The opening of the front end surface 6d of the rotary drum 6 is made close to the opening/closing door 5, and the outside of the abutment plate 6b on the rear end surface protrudes outward from the rear side wall 2b, and a gear 11 is provided on the outer periphery of the tip. The supported cylindrical shaft tube 10 is fixed. And the drive motor 12
By meshing the gear 13 of the shaft cylinder IO with the gear 11 of the shaft cylinder IO, the rotary drum 6 is rotated in a horizontal position. The rotation speed of the rotary drum 6 is preferably a low rotation speed, and normally a rotation speed of 72 rpm is provided. Reference numeral 14 designates an inner cylindrical body having one end fixed to the peripheral wall 6C and arranged concentrically at the center of the rotating drum 6 to rotate together with the rotating drum 6;
Many small holes 7 are provided in the peripheral wall. Reference numeral 15 denotes an infrared heater, which will be described later, which is disposed so that its radiation surface faces the inner circumferential surface of the inner cylinder 14, and one end of which is inserted into the shaft cylinder 10 and provided close to the outer frame 16. It is fixed to the fixing member 17.

In order to efficiently absorb radiant heat from an infrared heater 15 and an infrared heater 23, which will be described later, the rotating drum 6 and inner cylinder 14 are equipped with a ceramic enamel base having a high infrared absorption rate on the outer peripheral surface of the rotating drum 6 and inner cylinder 14. It is also possible to use a sintered material or a metal oxide. Furthermore, the material of the one-rotation drum 6 and the inner cylindrical body 14 is not limited to metal, but is an integrally molded product of ceramic material, which has high wear resistance and long life, and has a high infrared absorption rate. It's expensive, and it's expensive.

Since it is hygienic, it does not stain the coffee beans.

An exhaust port 18 for removing smoke is provided on the upper wall 2C of the furnace body 1, and a lighting lamp 19 is installed above the rear wall 2b to illuminate the inside of the furnace body l. A viewing window 20 is provided so that the state in which coffee beans are roasted within a rotating drum 6 can be visually confirmed. Reference numeral 21 denotes a guide member placed on the lower surface of the opening 3 to facilitate taking out the roasted coffee beans from the rotating drum 6, and 22 denotes a guide member placed on the bottom surface of the opening 3 to facilitate removal of the roasted coffee beans from the rotary drum 6. Reference numeral 22 denotes a guide member placed on the bottom surface of the opening 3 to facilitate removal of the roasted coffee beans from the rotary drum 6; Lower wall 2 to receive
The receiver placed on d so that it can be taken in and out is a plate.

23... are eight infrared heaters which are fixedly arranged on the left and right side walls 2e and 2f so as to surround the rotating drum 6 within the same plane and separated from each other by an appropriate distance. , and the direction of the a-emitting surface 24 is always toward the rotating drum 6.

In this embodiment, the infrared heater is
- We are using the one related to No. 3303.

This is made by embedding an electrothermal resistor such as a nichrome wire inside a ceramic material such as a glazed ceramic plate, so it is resistant to moisture, clean and sanitary, and has a large heat capacity and does not cool easily. Therefore, the temperature drop rate of the heater itself is slow and the fluctuation range with respect to the set temperature is small, so it has the advantage of being able to heat uniformly. Note that the ceramic plate may be curved or flat.

In addition, among the eight infrared heaters 23 arranged in the furnace body 1, the upper two infrared heaters are 100V 100W, and the lower six are 100V 200W, increasing the watt density to lower the temperature near the lower wall 2d of the furnace body 1. As another measure to prevent the temperature from decreasing, the lower heater mounting pitch may be closely spaced.

Note that when the single rotation drum 6 becomes long and a plurality of infrared heaters 23 are arranged along the length of the drum.

Since the viewing window 20 is provided on the opening/closing door s5, the opening/closing door 5
Heat dissipation from the furnace increases, and the temperature of the atmosphere inside the furnace near the opening/closing door side decreases. To deal with this, by setting the watt density of the heater 23 near the opening/closing door 5 higher than the watt density of the other heaters 23, it is possible to prevent the temperature near the opening/closing door 5 from decreasing and to uniformly heat the area.

The present invention has the above-mentioned configuration, and first, the infrared heater 23...
After passing current through the infrared heater 15 to raise the temperature inside the furnace body l to a predetermined temperature, the drive motor 12 is driven to rotate the rotary drum 6 while pouring an appropriate amount of green coffee beans from the input gutter 4 into the rotary drum 6. and an infrared heater 23. which is arranged to surround the rotating drum 6. ...and infrared rays are irradiated from inside and outside by an infrared heater 15 provided inside the inner cylinder 14.

Roast green coffee beans for a suitable amount of time. and,
After roasting is finished, the infrared heater 23...

15 is turned off, and the opening/closing door 5 is opened while rotating the rotary drum 6 to take out the roasted coffee beans. During roasting, the coffee beans are well stirred by the baffle plate 8 in the rotating drum 6, which helps to eliminate uneven roasting.

In the present invention, compared to the conventional hot air method, the radiant heat from the infrared heaters 23, . Because the rotary drum 6 is constantly rotating at a speed of 72 rpm, it receives convection heat evenly, which has a synergistic effect that quickly removes the boundary heat film on the surface of the coffee beans. It can be roasted in a matter of hours. Particularly in this case, there is an infrared heater 15 inside the rotating drum 6, more specifically inside the inner cylindrical body 14.
Because of this arrangement, infrared rays are irradiated from inside and outside, and heat is applied almost evenly to the coffee beans, almost eliminating uneven roasting. In this way, the same process is repeated for roasting.

Here, Fig. 3 shows the absorption characteristics of green coffee beans by infrared rays, and Fig. 4 shows the experimental results of the radiation characteristics of the infrared heater 15°23. Infrared absorption characteristics and infrared heaters 15.23
It was found that the radiation characteristics of the infrared heaters 15 and 23 are almost the same, indicating that the infrared heaters 15 and 23 according to the present invention are suitable for roasting green coffee beans.

Therefore, the experimental results of roasting each type of coffee bean using the infrared heater method according to the present invention and the conventional hot air method are shown in Table 1 below.

The degree of roasting was city roast.

As can be seen from this result, depending on the infrared heater method according to the present invention, the flavor and flavor can be reduced by
A refreshing and well-balanced coffee with few bad tastes such as "muddy taste", "dirty taste", and "unpleasant acidity" was obtained.

Next, Table 2 below shows the results of an experiment comparing the quality deterioration due to storage of Brazil No. 2 coffee beans roasted using the infrared heater method according to the present invention and the conventional hot air method.

Table 2 (+: good, ±: somewhat good, -: considerably deteriorated, -1 completely deteriorated) Conditions Storage temperature 37℃ Judgment method Cup test Coffee beans were stored in a pulverized state using a kraft paper bag From this result Hot air roasting The one at 37℃ for one day.

It already had an unpleasant sour taste and a sticky odor, and the deterioration had progressed further after the second day. On the other hand, with infrared roasting, there is less deterioration at any roasting temperature, and there is no unpleasant sourness, astringency, or hardness even when stored (there may be some changes from the second day onwards). However, it can be said that it is still in good condition, and it can be maintained until the 8th day.

Finally, Table 3 below shows the results of an experiment comparing the palatability of one can of coffee between roasting using the infrared heater method according to the present invention and roasting using the conventional hot air method.

Table 3 Milk type coffee extract 835
g Cow milk 100g Sand @ 65 and black sweetened type coffee extract 935
g Sugar 65g *; We conducted a questionnaire among 20 panelists and asked them to rank the results in order of very good, good, and bad. Very good was given 3 points, good was given 2 points, and bad was given 1 point. The total number of points scored.

[Effects of the Invention] As stated above, the present invention rotates and stirs coffee beans in a rotating drum, and uses infrared heaters arranged to surround the drum and infrared heaters installed inside the inner cylinder to heat infrared rays from inside and outside. Because we irradiated the green coffee beans and roasted them, there were almost no areas in the shadow of the irradiation.
In addition, together with the effect that infrared rays are easily absorbed inside the object to be heated, each coffee bean is heated by the present invention shown in FIG. Comparing the temperature changes of green coffee beans, it is clear that both the inside and outside are baked uniformly, with almost no uneven roasting, and it is possible to obtain roasted coffee beans of very high quality, with excellent flavor and aroma. Moreover, this provides remarkable effects such as increasing the shelf life of the roasted beans, making it possible to obtain roasted coffee beans that last longer, and making it easier to manage the coffee beans after roasting or grinding.

[Brief explanation of the drawing]

The figures relate to the present invention; Fig. 1 is a side sectional view of the main body of the device, Fig. 2 is a sectional view from the front, Fig. 3 is a curve diagram showing the infrared absorption spectrum of green coffee beans, and Fig. 4 is a sectional view of the main body of the device. Spectral distribution curve diagram of the infrared heater used in the invention, No. 5
The figure is a curve diagram showing temperature changes in green coffee beans when heated using a quartz tube heater as a heat source, and Figure 6 is a curve diagram showing temperature changes in green coffee beans when heated using an infrared heater according to the present invention as a heat source. It is. l...Furnace body, 2d...Front side wall, 4...Charging gutter. 5... Opening/closing door, 6... Rotating drum, 6d...
・Front end surface, 7... Small hole, 8... Baffle plate, 14
...Inner cylindrical body 15, 23...Infrared heater. Patent Applicant: Pokka Corporation I --No
Iλ viscosity v 11 official book 2.9! 3. Relationship with the case of the person making the amendment Patent applicant 5. -n Date of positive order Initiation 6. Subject of amendment In the specification, Detailed description of the invention J column . 7. Contents of correction

Claims (1)

[Claims] A furnace body is formed by a heat insulating wall, and a generally cylindrical rotating drum with a large number of small holes bored in the peripheral wall is supported approximately in the center of the furnace body so as to rotate in a horizontal position. A coffee bean roasting apparatus characterized in that an infrared heater is arranged on the inner wall surface of the furnace so as to surround the rotating drum, and an infrared heater is further provided in the center of the rotating drum.