Bean roaster

Abstract

To provide a bean roaster which can efficiently stir and roast beans with a small roasting blower and a low output heater by increasing stirring efficiency of beans and efficiency of heat added to the beans.SOLUTION: In a bean roaster 20 which blows out hot air guided by a fin device 10 toward a conical face of a roasting pot to stir and roast beans, the fin device 10 includes: an annular fin body 11 in which a plurality of fins 11a whose upper faces 11b are flat faces are arranged at intervals in a circumferential direction and which has seal parts 11c for preventing leakage of hot air by abutting on the conical face; and a fin disk 12 which includes outer peripheral edges 12a which abut on upper faces of the respective fins 11a, prevent leakage of hot air, are brought into close contact with the conical face 23g and blow out hot air from gaps S with the conical face 23g.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a highly efficient, compact, and inexpensive bean roaster that can roast beans, particularly nuts and coffee beans, evenly and efficiently in a short time. [Background technology]

[0002] BACKGROUND ART Conventionally, a bean roaster disclosed in Japanese Patent No. 3637434 and the like has been proposed as an apparatus for roasting coffee beans or similar beans using hot air.

[0003] These devices spray hot air from the center bottom of a mortar-shaped roasting pot along the inner surface of the roasting pot, stirring the beans while efficiently heating and roasting them.The chaff that peels off from the beans during roasting is sent to a filter device through a chaff recovery duct connected to the center of the top cover of the roasting pot, where it is separated from the air by a wire mesh filter and enters a chaff recovery box below.

[0004] In addition, the recovery structure for beans that have finished roasting in the roasting pot is such that an opening / closing member that opens and closes the bean recovery hole at the center bottom of the roasting pot moves upward to open the bean recovery hole, and the roasted beans fall from the bean recovery hole under their own weight and are recovered into the cooling chamber below via a cooling passage.

[0005] Furthermore, the cooling structure for roasted beans is designed so that the beans are cooled by air blown from a roasting blower, and the air used to cool the beans is sent to a filter device through a bean cooling duct and then exhausted outside the roaster.

[0006] However, unlike drum-type roasters, conventional hot air roasters do not have a drive mechanism for rotating or tilting the drum, so compared to drum-type roasters, they have a simpler structure, are less prone to malfunctions, and produce roasts with less unevenness in the beans.However, because the beans are stirred by wind power, a large-capacity, high-output roasting blower is required, and because the roasting blower also emits a large amount of heat, a large-capacity, high-output heater is also required. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 3637434 Summary of the Invention [Problem to be solved by the invention]

[0008] As shown in Figures 1 and 3 of Patent No. 3637434, the fins of the prior art have multiple fins arranged at equal intervals diagonally to the tangential direction on the backside of the upper cap, and closing members are provided at positions that form 90 degrees with each fin, designed to prevent hot air from escaping from these fins. However, the fins, which are arranged at equal intervals diagonally to the tangential direction, are themselves flat plate-like members that are slightly bent inward at their centers, and the end faces of these multiple fins come into contact with the conical roasting pot to form a passage for the hot air. Strictly speaking, there is always a gap between each fin and the roasting pot, and as a result, a leakage flow is generated that spreads radially, moving the beans toward the outside of the pot's periphery rather than rotating the beans circumferentially. With conventional fins, the beans are stirred on the outside of the pot when viewed from above. Naturally, the temperature of the pot and the hot air are lower on the outside than in the center, and therefore the beans are heated less efficiently than when the beans are stirred near the center of the pot.

[0009] In addition, the amount of airflow required to stir the beans increases to the extent that leakage occurs, which is one of the reasons why roasting blowers have to be larger.

[0010] Furthermore, the method of fixing the multiple fins to the upper cap was to use two fin fixing screws, nuts, and spring washers for each fin, and the actual mass-produced part consisted of 28 fins and 168 fixing parts, which required a long time to assemble, making it poorly productive and very expensive.

[0011] In order to solve these problems, the bean roaster of this invention is a bean roaster that is designed to spray hot air from the central bottom of a mortar-shaped roasting pot partially along the surface of the roasting pot, stirring the beans while heating and roasting them efficiently.The object of this invention is to provide an inexpensive, compact bean roaster that consumes little power, makes little noise, and can efficiently stir and roast beans using a small roasting blower and a low-output heater by optimizing the fin structure inside the roasting pot to further improve the efficiency of bean stirring and the efficiency of heat applied to the beans. [Means for solving the problem]

[0012] In order to achieve the above object, the invention of claim 1 is a bean roasting machine that has a mortar-shaped roasting kettle with a conical surface formed on the inside, and is provided with a fin device that guides hot air supplied from the central bottom of the roasting kettle in a direction oblique to the radial direction of the roasting kettle, and sprays the hot air guided by the fin device toward the conical surface to stir and roast the beans, the fin device having an annular fin body with a plurality of fins with flat upper surfaces arranged at intervals in the circumferential direction on the upper surface of the base and a sealing portion on the lower surface of the base that abuts against the conical surface to prevent leakage of hot air, and a fin disk that abuts against the upper surfaces of the fins to prevent leakage of hot air and has an outer peripheral edge that is close to the conical surface and sprays hot air from a gap with the conical surface, the fin body and the fin disk are connected by a fastening means and are removably fixed to the central bottom of the roasting kettle.

[0013] According to the invention of claim 1, by arranging a plurality of fins on the upper side of the fin body and making the upper surface of the fin flat, and by abutting the fin disk on this surface, leakage of air from this portion can be prevented.

[0014] In addition, a seal portion is provided on the underside of the fin body to abut against the conical surface of the roasting pot and prevent leakage of hot air, thereby preventing leakage from this portion.

[0015] Furthermore, the structure allows hot air to be ejected from the gap between the outer edge of the fin disc and the conical surface of the roasting pot, and the flow is narrowed in this area so that the hot air is ejected along the conical surface of the roasting pot. This not only allows the high-temperature hot air to hit the beans directly and heat them efficiently, but also has the effect of preventing small pieces of beans from entering the center of the roasting pot, even if small pieces of beans remain in the roasting pot after the roasting blower is stopped, because this gap can be set small.

[0016] In the invention of claim 2, the material of the fin body is stainless steel that can be cast, and the fastening means is a screw connection means.

[0017] According to the invention of claim 2, the fin body can be integrally formed by using the inexpensive lost wax method to form multiple fins. Therefore, even if four screws are used, the total number of parts in the fin device is only about six, compared to the total number of parts of a conventional fin of 197, making it possible to provide a bean roaster equipped with a fin device that is extremely highly productive and inexpensive.

[0018] The invention of claim 3 is a bean roasting machine that has a mortar-shaped roasting kettle with a conical surface formed on the inside, and is provided with a fin device that guides hot air supplied from the central bottom of the roasting kettle in a direction oblique to the radial direction of the roasting kettle, and sprays the hot air guided by the fin device toward the conical surface to stir and roast the beans. The fin device has an annular fin body with multiple fins spaced apart circumferentially on the upper surface of a plate-shaped base and a sealing portion on the lower surface of the base that abuts against the conical surface to prevent leakage of hot air, and a fin disk that is connected to the upper parts of the fins to prevent leakage of hot air from the upper parts of the fins and has an outer peripheral edge that is close to the conical surface and sprays hot air from a gap with the conical surface, and the fin body and the fin disk are formed integrally and are detachably fixed to the central bottom of the roasting kettle.

[0019] According to the invention of claim 3, like the invention of claim 1, leakage from the top of the fins and the seal portion can be prevented, the beans can be heated efficiently, and small pieces can be prevented from penetrating the center of the roasting pot. Furthermore, because the invention of claim 3 integrally forms the fin body and the fin disk, there is no need for a connecting member to connect the two parts, and the number of parts can be reduced.

[0020] In the invention of claim 4, the fin body and the fin disks are made of a stainless steel material that can be cast.

[0021] According to the invention of claim 4, the entire fin device can be integrally formed by casting multiple fins and fin discs using the inexpensive lost wax method, so the number of parts is reduced to just one, compared to the total number of 197 parts required for conventional fins. This improves productivity even compared to when the fin body and the fin disc are separated, making it possible to provide a bean roaster equipped with an even cheaper fin device.

[0022] In the invention of claim 5, the fin body has a hot air inlet that takes in hot air supplied from the central bottom of the roasting pot, a plurality of hot air passages formed between adjacent fins that guide the hot air taken in from the hot air inlet into the gaps, and a hot air blocking section that restricts the hot air taken in from the hot air inlet so as not to move into the gaps, there are at least eight of each hot air passage and they are formed in an arc shape to guide the hot air in a direction oblique to the radial direction of the roasting pot, and the vertical spacing is gradually narrowed from the hot air inlet towards the gaps, and the hot air blocking section is provided in at least three or more places between adjacent hot air passages.

[0023] According to the invention of claim 5, the vertical spacing of the hot air passage is wide on the inlet side and narrow on the outlet side, and the passage is smoothly curved in an arc shape, so that the hot air entering from the inlet is forcefully ejected from the outlet side in a direction oblique to the radial direction of the roasting pot without significant windage loss, and therefore the beans can be stirred efficiently even with a roasting blower with low output.

[0024] Furthermore, the structure is such that at least three hot air blocking sections are provided between multiple hot air passages, so the beans move as follows on the conical surface of the roasting pot:

[0025] Near the opening of the fins, the beans receive the hot air that is ejected through the hot air passage and move along the conical surface of the roasting pot, diagonally upward relative to the radial direction, in the direction of the hot air ejection.When they then enter an area where hot air is not being ejected, their own weight causes them to roll down along the conical surface (slope) of the roasting pot to near the center.The beans repeat these two movements as they move along the conical surface of the roasting pot, and as a result, when viewed from above, the beans snake around the fin device, i.e., they are heated and stirred while undulating.

[0026] With the action of the invention of claim 5, all of the hot air that sprays out from the gap between the fin disc and the roasting pot in a direction oblique to the radial direction of the roasting pot is used to stir the beans in the radial direction, and the beans are heated and stirred while meandering near the center of the fin device, that is, while undulating, so the efficiency of heating and stirring the beans is improved, and when roasting the same amount of beans, it is possible to reduce the output (= input) of the roasting blower compared to conventional fin devices.As a result, there is no need to exhaust excess heat from the heater outside the roaster, so a heater with a smaller output can be used, and as a result, it is possible to provide an inexpensive, compact bean roaster with low power consumption and low noise. [Effects of the Invention]

[0027] According to the present invention, because the fin body and the conical surface are in contact with each other, all of the hot air supplied from the central bottom of the roasting pot is guided diagonally to the radial direction of the roasting pot, allowing the beans to be efficiently heated and stirred near the center of the roasting pot, which minimizes heat loss and windage loss of the hot air supplied to the roasting pot.As a result, the heater device and roasting blower can be made smaller, which has the effect of providing an inexpensive, low-power roasting machine. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a perspective view of a bean roaster according to the present invention; [Figure 2] Partial cross-sectional view showing the main components of the bean roaster according to the present invention. [Figure 3] A partially enlarged cross-sectional view showing the central bottom side of the roasting pot according to the present invention. [Figure 4] FIG. 1 is a perspective, partially sectional view of a fin body according to the present invention; [Figure 5] Image of beans being stirred by the fin device according to the present invention [Figure 6] Partially enlarged cross-sectional view showing the central bottom side of a conventional roasting pot [Figure 7] 1 is a perspective view of a conventional fin device; [Figure 8] Image of beans being stirred using a conventional fin device [Figure 9] A graph comparing the pressure (wind pressure) characteristics of the fin device of the present invention and a conventional fin device. [Figure 10] Roasting temperature graphs for the fin device of the present invention and a conventional fin device [Figure 11] Graph showing the difference in roasting depth between the fin device of the present invention and the conventional fin device DETAILED DESCRIPTION OF THE INVENTION

[0029] Figures 1 to 5 show one embodiment of a roaster according to the present invention. As shown in Figures 1 to 4, bean roaster 20 according to this embodiment is made up of the following parts:

[0030] That is, the roasting pot 23 for roasting coffee beans, the heater device 40 which is the heat source of the roasting pot 23, the roasting blower 37 for sending high-pressure air into the heater device 40 and sending the air (hot air) heated by the heater device 40 into the roasting pot 23, the chaff recovery duct 28 for passing the exhaust air containing chaff from the roasting pot 23, the cyclone 42 for taking in the exhaust air through the chaff recovery duct 28 and separating the chaff from the exhaust air, the chaff recovery box 44 for collecting the chaff separated by the cyclone 42, the bean recovery mechanism 48 including the bean recovery door 49 for opening and closing the bean recovery hole (not shown) of the roasting pot 23, the bean recovery passage 47 which is in communication with the bean recovery hole 23h and which guides the roasted beans discharged from the bean recovery hole 23h out of the roasting pot 23, and the bean recovery passage 47 which is in communication with the outlet 47b of the bean recovery passage 47. The system comprises a bean cooling box 51 for receiving the roasted beans that have flowed out from the recovery passage 47, a bean storage box 52 that is detachably stored within the bean cooling box 51 and for storing the roasted beans that have flowed into the bean cooling box 51, a bean cooling fan 53 that is provided in the bean cooling box 51 and blows air into the bean storage box 52 to cool the roasted beans, a bean cooling duct 54 that is connected to the exhaust port 51c of the bean cooling box 51 and ventilates the exhaust air that has cooled the roasted beans, an exhaust duct 43 that is connected to the cyclone 42 and ventilates the exhaust air from which the chaff has been separated inside the cyclone, and an exhaust collecting pipe 45 that connects the outlet sides of the exhaust duct 43 and the bean cooling duct 54 and collects the exhaust air from the exhaust duct 43 and the bean cooling duct 54 and ventilates it outside the roaster 20.

[0031] In roaster 20 configured as described above, air blown from roasting blower 37 is heated by heater device 40 as shown by the dashed arrow in Fig. 2, and is supplied as hot air into roasting pot 23 to roast the coffee beans therein. After roasting, the air passes through chaff collection duct 28 to cyclone 42 as shown by the two-dot chain arrow in Fig. 2, where the chaff is collected in chaff collection box 44, while the air is blown through exhaust duct 43 to exhaust manifold 45 and discharged outside roaster 20. Meanwhile, air blown from bean cooling fan 53 is introduced into bean storage box 52, where it cools the roasted coffee beans as shown by the one-dot chain arrow in Fig. 2, and is then blown through bean cooling box 51 and bean cooling duct 54 to exhaust manifold 45 and discharged outside roaster 20.

[0032] The coffee beans are roasted and cooled and the chaff is discarded by the air flow described above, and roasted coffee beans are provided, but the distinctive feature of the bean roaster according to this embodiment is the fin device 10.

[0033] Hereinafter, the structure of the roasting pot 23 in which the fin device 10 is installed will be described with reference to Figs. 1 to 5, and then the structure of the fin device 10 will be described.

[0034] 1 and 2, roasting pot 23 is shaped like a mortar, with the inside of side wall 23e of roasting pot 23 being a conical surface 23g, and coffee beans are supplied into side wall 23e through hopper 33, and roasting takes place inside conical surface 23g. The central bottom of roasting pot 23, i.e., the lower end of conical surface 23g, is connected to cylindrical hot air intake duct 23a, which allows hot air blown from heater device 40 to be taken into roasting pot 23.

[0035] The fin device 10 according to this embodiment is detachably fixed to the central bottom of the roasting pot 23 configured as described above.

[0036] Below, the structure of the fin device 10 according to this embodiment will be described in detail by comparing the fin devices 10 and 60 with reference to Figures 3 to 5 which show the fin device 10 and Figures 6 to 8 which show a conventional fin device 60.

[0037] As shown in FIG. 3, the fin device 10 is composed of a fin body 11 formed in an annular shape and a fin disk 12 that closes the upper surface of the fin body 11.

[0038] The fin body 11 is made of stainless steel and has a plate-shaped base 11f, as shown in Figures 3 and 4, and has a hot air intake port 11g on the inside of the base 11f that communicates with the hot air intake duct 23a.

[0039] 4, the upper surface of the base 11f has a plurality of (16) fins 11a spaced apart in the circumferential direction and four hot air blocking sections 11d arranged to separate each fin 11a into groups of four, and hot air passages 11h are formed between adjacent fins 11a and between a hot air blocking section 11d and the adjacent fin 11a, which guide the hot air taken in from the hot air intake port 11g to a gap S (the gap between the outer peripheral edge of the fin disk 12 and the conical surface 23g) described below. Each hot air blocking section 11d is in surface contact with the lower surface of the fin disk 12 and is configured to restrict the hot air taken in from the hot air intake port 11g from moving into the gap S.

[0040] The 20 hot air passages 11h configured in this manner have arc-shaped sides of each fin 11a and each hot air blocking section 11d, so the hot air passages 11h are also arc-shaped. In addition, the hot air passages 11h are formed so that the vertical spacing between them gradually narrows from the hot air intake port 11g toward the gap S.

[0041] With the above-described configuration of the hot air passage 11h, as shown by the solid arrow in Figure 5, the hot air entering from the hot air intake 11g is ejected as a powerful swirling flow from the gap S in a direction oblique to the radial direction of the roasting pot without significant windage loss, so that even a roasting blower 37 with low output can efficiently stir the beans B.

[0042] Each fin 11a formed on the upper surface of the base 11f has a thickness of 1.5 mm, and its upper surface 11b is flat so as to abut against the lower surface of the fin disk 12, so that it also abuts (makes surface contact with) the fin disk 12, and as a result, leakage flow from this part is negligibly small.

[0043] On the other hand, a seal portion 11c that abuts (is in surface contact with) the conical surface 23g is formed on the underside of the base 11f of the fin body 11, so that leakage flow from between the underside of the base 11f and the conical surface 23g can be made negligibly small.

[0044] In this way, leakage of air from the fin device 10 is restricted, and all of the hot air taken into the fin device 10 passes through the hot air passage 11h.

[0045] 5, the fin disk 12 is formed in a circular shape, and its outer circumferential edge 12a is disposed close to the conical surface 23g of the roasting pot 23, forming a gap S between the outer circumferential edge 12a and the conical surface 23g. This allows the hot air that has passed through the hot air passage 11h to be ejected along the conical surface 23g through the gap S.

[0046] The fin body 11 and fin disk 12 configured in this manner have screw holes at each hot air blocking section 11d, and the fin body 11 and fin disk 12 are integrated together by a screw connecting means, which is a fastening means, to form the fin device 10.

[0047] Since the fin device 10 of this embodiment has the above-mentioned configuration, the hot air ejected from near the outlet (gap S) of the hot air passage 11h flows diagonally upward relative to the radial direction of the conical surface 23g, as shown by the solid arrow in Figure 5.

[0048] Receiving this hot air, the beans B move diagonally upward relative to the radial direction of the conical surface 23g, which is the direction in which the hot air is ejected. Then, when they enter the hot air blocking section 11b area where hot air is not being ejected, their own weight causes them to roll down to near the center along the (inclined) conical surface 23g of the roasting pot 23. The beans B repeat these two movements as they move along the conical surface 23g of the roasting pot 23, and as a result, as shown by the dashed-dotted arrow in Figure 5, the beans B are heated and stirred while meandering near the fin device 10 when viewed from above, i.e., while undulating, as shown by the dashed-dotted arrow in Figure 5. Considering that the surface temperature and hot air temperature of the roasting pot 23 are highest near the center of the pot and decrease closer to the outer periphery, the roaster 20 according to this embodiment has a structure that rotates and stirs the beans B as close to the center of the pot as possible, resulting in extremely high heat transfer efficiency to the beans B.

[0049] Furthermore, according to the roaster 20 of this embodiment, the outer diameter of the fin disc 12 and the clearance of the conical surface 23g can be set as desired regardless of the height of the outlet opening of the hot air passage 11h, so it is possible to set the outer diameter of the fin disc 12 and the clearance of the conical surface 23g to 2 mm or less without excessively narrowing the hot air passage 11h, preventing fragments of beans B from passing through the fin device 10 and accumulating in large quantities in the roaster inlet trap 23c when the roast blower 37 is stopped.

[0050] In the above embodiment, 20 hot air passages 11h are provided and four hot air blocking sections 11d are provided, but it is sufficient to configure the system so that at least eight hot air passages 11h are provided and at least three hot air blocking sections 11d are provided.

[0051] Next, in order to clarify the advantageous effects of the fin device 10 according to this embodiment, a conventional fin device 60 will be described below with reference to Figures 6 to 8. Note that in Figure 7, the screws, nuts, and washers are shown in a see-through state in order to clearly show how these components are installed.

[0052] 6 and 7, a conventional fin device 60 has a structure in which 24 fins 62 for forming the hot air passages made by bending thin plate 0.5 mm thick on a fin disk 61, and four closing members 63 for forming the hot air blocking section made by bending thin plate similarly 0.5 mm thick, are fixed each with two fin fixing screws 64, two nuts 65, and two washers 66. As a result, one fin device 60 is made up of 28 thin plate parts and 56 screws, nuts, and washers, for a total of 197 parts, which is an extremely large number, and as a result, it takes a long time to assemble the fin device 60.

[0053] Here, the fin seal portion 62a and the closure member seal portion 63a of the fin 62 and the closure member 63 are 0.5 mm thick and have linear surfaces, so even when these surfaces are brought into contact with the conical surface 23g, the linear seal portions 62a, 63a of the conical surface 23g prevent air leakage. However, with this structure, when the bottom ends of the fin seal portion 62a and the closure member seal portion 63a come into contact with the conical surface 23g, a gap of at least 0.3 mm is usually formed. If the design and installation precision of the conical surface 23g is poor, a gap of about 0.5 mm may occur, causing leakage air to spread radially from the center of the kettle.

[0054] The fins 62 and the closing member 63 configured in this manner cause the beans B in the roasting pot 23 to be stirred as shown in FIG.

[0055] That is, near the opening of fin 62, beans B receive the hot air that is ejected through the hot air passage and move on conical surface 23g of roasting pot 23 in the direction of the hot air ejection, i.e., diagonally upward relative to the radial direction, and then when they enter an area where hot air is not being ejected, they roll down due to their own weight to near the center along conical surface 23g (slope) of roasting pot 23. Beans B move in an undulating manner on conical surface 23g of roasting pot 23, repeating these two movements.

[0056] However, in the case of the conventional structure, the hot air blown out from near the opening of the fin 62 is blown out obliquely upward relative to the radial direction of the conical surface 23g (solid arrow in Fig. 8), and there is also a leakage flow (dashed arrow in Fig. 8) that flows radially from a gap of about 0.5 mm between the seal portions 62a, 63a and the conical surface 23g, causing the beans B to move to the outer periphery of the pot. As a result, in the structure using the conventional fin device 60, the beans B are heated and stirred while meandering at a position away from the fin device 60 (a position close to the outer periphery of the pot), resulting in lower thermal efficiency compared to this embodiment.

[0057] Next, with reference to Figures 9 to 11, we will explain the difference in performance when the fin device 10 according to this embodiment and the conventional fin device 60 are installed in the same roaster. Note that Figure 9 is a graph comparing the pressure (wind pressure) characteristics of the fin device 10 and the fin device 60, with the horizontal axis representing the DC input voltage to the roasting blower 37 and the vertical axis representing the pressure (wind pressure), with the pressure measured inside the heater 40. Also, although the roasting blower 37 operates on AC 200V, changing the DC input voltage changes the rotation speed; the higher the DC input voltage, the higher the rotation speed and the corresponding increase in pressure (wind pressure).

[0058] Generally, the more grams of raw beans there are, the higher the pressure (wind pressure) required to agitate the raw beans, and even if the fin devices 10 and 60 are different, the pressure (wind pressure) required to agitate beans B is almost the same.

[0059] The performance of roast blower 37 is generally expressed in terms of PQ characteristics (pressure and air volume), but since the relationship between the pressure P and flow rate Q of roast blower 37 is proportional if the roasting machine is the same, we compared the values ​​of pressure P, which is easy to measure.

[0060] Here, the pressure (wind pressure) required to stir and roast 200g of green beans using the fin device 10 according to this embodiment is 4.5kPa, and the input voltage at that time is DC 6. In contrast, the fin device 60 requires a voltage of approximately DC 7V, which increases the rotation speed of the roasting blower 37 accordingly, resulting in not only increased power consumption but also an increase in the amount of heat required for roasting that is discharged outside the roaster 20.

[0061] The main reason for this is that, as mentioned above, the fin device 10 stirs and roasts the beans using only the swirling flow, whereas the fin device 60 generates leakage flow in addition to the swirling flow.

[0062] Figure 10 shows the difference in performance in terms of temperature changes inside the roaster during roasting. Figure 10 shows the temperature change characteristics when roasting using different fin devices 10, 60 for the same roasting profile (target temperature). Here, the measured temperatures were detected by the temperature sensor 36 inside the chaff recovery duct 28 shown in Figure 2. This graph also shows the results when 200g of green beans were roasted for 5 minutes and 20 seconds using the roaster of the present invention in medium-speed dark roast mode (L8). Furthermore, the heater output of the heater 40 installed in the roaster 20 is 8kW.

[0063] First, the characteristics of the fin device 10, indicated by the dashed line, will be explained. During the moisture removal process, which maintains a temperature of 150°C for 1 minute 20 seconds after the start of roasting, the temperature exceeds 150°C once at around 32 seconds and then stabilizes. During the rapid heating process from 1 minute 20 seconds to 4 minutes, the temperature exceeds the roasting profile once at around 2 minutes 32 seconds and then stabilizes, and remains at roughly the same temperature as the roasting profile until the end of roasting.

[0064] On the other hand, the conventional fin device 60, shown by the dashed line, remains below the 150°C line for most of the moisture removal process, maintaining a temperature of 150°C for 1 minute 20 seconds after the start of roasting. Even in the rapid heating process from 1 minute 20 seconds to 4 minutes, the temperature remains below the roasting profile, and it is only after 4 minutes that the temperature reaches the same level as the roasting profile.

[0065] Therefore, when comparing the fin device 10 and the fin device 60, even though they are operated using the same heater 40 and roasting blower 37 and the same roasting profile, the actual temperature during roasting with the fin device 10 is closer to the roasting profile (target temperature), and it can be seen that heat penetrates the beans better.

[0066] Figure 11 shows data on the finished state of beans when they are actually roasted under the conditions shown in Figure 10. The roasted beans are finely ground and measured with a colorimeter, and the L value is shown. The smaller the L value, the darker the roast.

[0067] As shown in Figure 10, the L value when roasting in the medium-speed dark roast mode (L8) is L = 16.3 when using the fin device 10 shown by the dashed line, and L = 17.3 when using the fin device 60 shown by the dotted line, and it is clear that the coffee is roasted more deeply when using the fin device 10 of this embodiment.

[0068] For reference, the All Japan Coffee Association classifies L values ​​between 16.5 and 18.5 as full city roast, and between 15.0 and 16.5 as French roast. According to this classification, the roast level when using the Finn device 60 is classified as full city roast, and the roast level when using the Finn device 10 is classified as French roast.

[0069] If you want to achieve a roast level of about L=17.3 using the fin device 10, you can do so by setting the roast depth setting to approximately 7, as shown in Figure 11.

[0070] Furthermore, the roaster 20 using the fin device 10 of this embodiment can set the roast depth in eight stages from L1 to L8. When considering the risk of fire, it is ideal to achieve a dark roast without raising the final temperature of the roasting profile too much, but when it comes to light roasts, the final temperature of the roasting profile is lowered, so there is no need to pay much attention to this when designing the structure of the roaster.

[0071] As explained above, in the roaster 20 using the fin device 10 according to this embodiment, the fin body 11 is made of stainless steel, so it can be manufactured using inexpensive methods such as the lost-wax casting method. Furthermore, because the fins 11a and fin disks 12 abut, and the seal portion 11c of the fin body 11 abuts against the conical surface 23g, the beans can be efficiently heated and stirred near the center of the roasting pot 23, with extremely low heat loss and windage loss. This allows the heater device 40 and roasting blower 37 to be made smaller, which has the effect of providing an inexpensive roaster 20 with low power consumption.

[0072] In the fin device 10 according to the above embodiment, the fin body 11 and the fin disk 12 are formed separately and these parts are connected by screw connections, but the fin body and the fin disk may be formed from a stainless steel material that can be cast, and these parts may be integrally formed by casting (not shown).

[0073] According to this embodiment, as with the previous embodiment, leakage from the top of the fins and the seal portion can be prevented, beans can be heated efficiently, and small pieces can penetrate to the center of the roasting pot. Furthermore, since the entire fin device can be integrally formed by using the inexpensive lost wax method to form multiple fins and fin disks, the number of parts is only one compared to the total number of 197 parts for conventional fins, and productivity is improved even compared to when the fin body and the fin disk are separated, making it possible to provide a bean roaster equipped with a fin device that is even more inexpensive. [Explanation of symbols]

[0074] 10 Fin device 11 Fin body 11a Fins 11b Top of fin 11c Seal part 11d Hot air blocking section 11f Base of the fin body 11g Hot air intake 11h Hot air passage 12 Fin disc 12a Outer edge of fin disc 20 roaster 23 Roasting pot 23a Hot air intake duct 23g conical surface

Claims

1. A bean roaster has a mortar-shaped roasting pot with a conical surface formed inside, and is provided with a fin device that guides hot air supplied from the center bottom of the roasting pot in a direction oblique to the radial direction of the roasting pot, and the hot air guided by the fin device is sprayed toward the conical surface to stir and roast the beans. The fin device an annular fin body having a plurality of fins with flat upper surfaces arranged at intervals in the circumferential direction on an upper surface of a plate-like base, and a sealing portion on a lower surface of the base that abuts against the conical surface to prevent leakage of hot air; a fin disk having an outer peripheral edge portion that contacts the upper surface of each fin to prevent leakage of hot air and that is close to the conical surface to eject hot air from a gap between the conical surface and the outer peripheral edge portion; The fin body and the fin disk are connected by a fastening means and are detachably fixed to the central bottom of the roasting pot. A bean roasting machine characterized by:

2. The fin body is made of stainless steel, which can be cast, and the fastening means is a screw fastening means.

2. The bean roaster according to claim 1 .

3. A bean roaster has a mortar-shaped roasting pot with a conical surface formed inside, and is provided with a fin device that guides hot air supplied from the center bottom of the roasting pot in a direction oblique to the radial direction of the roasting pot, and the hot air guided by the fin device is sprayed toward the conical surface to stir and roast the beans. The fin device an annular fin body having a plurality of fins arranged at intervals in the circumferential direction on an upper surface of a plate-like base and a seal portion on a lower surface of the base that abuts against the conical surface to prevent leakage of hot air; a fin disk connected to the upper portion of each fin to prevent leakage of hot air from the upper portion of each fin, and having an outer peripheral edge portion adjacent to the conical surface to eject hot air from a gap between the conical surface, The fin body and the fin disk are integrally formed and detachably fixed to the central bottom of the roasting pot. A bean roasting machine characterized by:

4. The fin body and the fin disc are made of stainless steel, which can be cast.

4. The bean roaster according to claim 3.

5. The fin body has a hot air intake port that takes in hot air supplied from the central bottom of the roasting pot, a plurality of hot air passages that are formed between adjacent fins and that guide the hot air taken in from the hot air intake port to the gap, and a hot air blocking section that restricts the hot air taken in from the hot air intake port so that it does not move to the gap, The hot air passages are provided in at least eight pieces, and are formed in an arc shape so as to guide the hot air in a direction oblique to the radial direction of the roasting pot, and are formed so that the vertical spacing between the hot air passages gradually narrows from the hot air intake port toward the gap, The hot air blocking sections are provided in at least three locations between adjacent hot air passages. The bean roaster according to any one of claims 1 to 4.

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