Roasting equipment

Abstract

To provide a roaster which can maintain a temperature of a roaster furnace at a target temperature irrespective of variation in casings, keeping quality of roasted products constant.SOLUTION: A roaster which roasts a material to be roasted by introducing air heated with a heater 51 into a roaster furnace 70 includes: first temperature detection means 62 which detects a temperature of air flowing into the roaster furnace 70; second temperature detection means 73 which detects a temperature of an inside of the roaster furnace 70; and a controller 80 which performs temperature adjustment control for controlling the temperature of the inside of the roaster furnace 70 to a target temperature. The controller 80, in the temperature adjustment control, sets a temperature lower by a predetermined value than the target temperature as a reference temperature, controls electric current passage to the heater so that the temperature detected by the first temperature detection means 62 becomes the reference temperature, calculates a corrected value from the target temperature and the temperature detected by the second temperature detection means 73, and updates the reference temperature on the basis of the corrected value.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a roasting apparatus that roasts roasted materials such as coffee beans using heated air.

Background Art

[0002] Conventionally, as a device for roasting roasted materials such as green coffee beans, a hot air type roasting apparatus that uses heated air is known. The hot air type roasting apparatus includes, for example, a fan that generates an air flow, a heater assembly that includes a heater that heats the air, and a roasting chamber that roasts the roasted material, as shown in Patent Document 1.

[0003] In the roasting apparatus configured as described above, the air flow generated by the rotation of the fan flows into the downstream heater assembly, where it receives heat from the heater and is heated to become hot air. The hot air is further supplied into the downstream roasting chamber, and the unroasted material in the roasting chamber is roasted by being heated by the hot air.

[0004] Also, roasting is performed by applying a heat-to-time curve called a roasting profile to the roasted material. In the roasting apparatus, in order to maintain the temperature of the roasting chamber at the temperature specified in the roasting profile, a temperature sensor for detecting the temperature of the roasted material or the roasting chamber is provided, and the output of the heater is controlled based on the detection result of this temperature sensor. The position where the temperature sensor is installed varies depending on the roasting apparatus. In Patent Document 1, an example is shown in which two of the three sensors, namely, a sensor for detecting the temperature of the air flowing into the apparatus, a sensor for detecting the temperature of the air entering the roasting chamber, and a sensor for detecting the temperature of the air exiting the roasting chamber, are combined to detect the temperature at multiple locations.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] To obtain roasted coffee by executing a profile, it is crucial to maintain the roasting chamber temperature at the specified level. Therefore, it is necessary to appropriately control the heater output based on the temperature detected by the temperature sensor. However, because there are individual differences in the components that make up the roasting equipment, the ease with which the roasting chamber temperature rises varies from one enclosure to another. Furthermore, the ease with which the temperature rises is also affected by the operating environment (room temperature), so if conditions that easily raise the temperature are met, the temperature of the roasting chamber will exceed the specified temperature, resulting in the problem of not being able to maintain a consistent quality of roasted coffee. To solve this problem, there is room for improvement in heater control.

[0007] The present invention aims to solve the above problems by providing a roasting apparatus that can maintain the temperature of the roasting chamber at a target temperature and keep the quality of the roasted product consistent, even if there are variations depending on the housing, by appropriately controlling the heater. [Means for solving the problem]

[0008] This invention relates to a fan that generates airflow, A heater that heats the air, A roasting kettle that takes in heated air to roast the roasted items, A first temperature detection means for detecting the temperature of the air flowing into the roasting kettle, A second temperature detection means for detecting the temperature inside the roasting kettle, The roasting machine includes a control device that performs temperature control to control the temperature inside the roasting machine to a target temperature. The control device sets a reference temperature that is a predetermined value lower than the target temperature in the temperature control, controls the power supply to the heater so that the temperature detected by the first temperature detection means becomes the reference temperature, and the target temperature and the temperature detected by the second temperature detection means The difference between the two is calculated, and the temperature difference This roasting apparatus calculates a correction value and updates the reference temperature based on the correction value. [Effects of the Invention]

[0009] By configuring the system as described above, the roasting device can maintain the temperature of the roasting drum at the target temperature, thereby ensuring consistent quality of the roasted products. [Brief explanation of the drawing]

[0010] [Figure 1] This is a cross-sectional view of the roasting apparatus according to this embodiment. [Figure 2] This graph shows an example of a roasting profile. [Figure 3] This is a block diagram of the control device in the roasting apparatus of this embodiment. [Figure 4] This is a flowchart of the temperature control in the roasting apparatus of this embodiment. [Figure 5] This graph shows the relationship between the reference temperature and the temperature inside the roasting drum during temperature control. [Modes for carrying out the invention]

[0011] A preferred embodiment of the present invention will be briefly described by illustrating its operation.

[0012] The present invention relates to a roasting apparatus comprising a fan for generating airflow, a heater for heating air, a roasting drum for taking in heated air and roasting the roasted product, a first temperature detection means for detecting the temperature of the air flowing into the roasting drum, a second temperature detection means for detecting the temperature inside the roasting drum, and a control device for performing temperature control to control the temperature inside the roasting drum to a target temperature. In temperature control, the control device sets a reference temperature that is a predetermined value lower than the target temperature, controls the power supply to the heater so that the temperature detected by the first temperature detection means becomes the reference temperature, calculates a correction value from the target temperature and the temperature detected by the second temperature detection means, and updates the reference temperature based on the correction value. In other words, after starting temperature control with a reference temperature set lower than the target temperature, the reference temperature is corrected from the temperature difference between the target temperature and the roasting drum, thereby preventing the temperature of the roasting drum from exceeding the target temperature even if there are individual differences in the parts. Furthermore, by controlling the power supply to the heater using the first temperature detection means, which is closer to the heater, the temperature change can be controlled linearly, thus maintaining the temperature of the roasting drum at the target temperature.

[0013] Furthermore, after setting or updating the reference temperature, the control device calculates a correction value when it determines that the temperature detected by the second temperature detection means has stabilized. For example, if the temperature of the roasting drum is rising or fluctuating during temperature adjustment, the correction value cannot be properly obtained, and therefore no correction is performed. This prevents unnecessary corrections and allows the temperature of the roasting drum to be maintained at the target temperature more reliably.

[0014] Furthermore, after setting or updating the reference temperature, the control device does not calculate the correction value for a predetermined period of time. Even if the reference temperature is set or updated, the temperature of the roasting drum does not rise immediately; there is a time lag before the temperature rises. If this time lag is mistakenly detected as the temperature stabilizing, it may become impossible to properly control the heater. Therefore, by not calculating the correction value for a predetermined period of time, such misdetection can be prevented.

[0015] Further, the control device calculates a correction value by multiplying the difference between the target temperature and the temperature detected by the second temperature detection means by a coefficient K (0 < K < 1), and updates the reference temperature by adding the correction value to the reference temperature. As a result, the correction value can be appropriately set, so that the temperature of the roasting pot can be more reliably maintained at the target temperature.

Embodiment

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0017] FIG. 1 is a cross-sectional view of the roasting apparatus of the present embodiment. The roasting apparatus 1 of the present embodiment is an apparatus mainly used for roasting coffee beans, and includes a main body 10 for roasting coffee beans as the object to be roasted, and a chaff case 20 for collecting the thin skins of coffee beans peeled off during the roasting process. The chaff case 20 is detachably provided above the main body 10.

[0018] The main body 10 includes a fan 40 for generating an air flow, a motor 41 for rotating the fan 40, a fan case 42 for rectifying the air flow generated by the rotation of the fan 40, a heater unit 50 provided downstream of the fan 40 for heating the air, a heater case 60 for housing the heater unit 50, and a roasting pot 70 for taking in the air heated by the heater unit 50 and roasting the object to be roasted.

[0019] Intake ports 31 for taking air into the main body 10 are provided at the upper and lower portions of the outer casing 30, and air flows into the main body 10 from the intake ports 31 when the fan 40 rotates. The air taken in from the upper intake port 31 flows downward along the outer casing 30 and toward the bottom of the main body 10. This air flow suppresses the heat generated from the heater unit 50 from being transmitted to the outer casing 30 and prevents the surface temperature of the outer casing 30 from rising. Then, the air flowing into the main body 10 from the intake port 31 is rectified by the fan case 42 and heads toward the heater unit 50.

[0020] The heater unit 50 is equipped with a heater 51 that generates heat. An air intake 521 is provided on the bottom of the heater unit 50, and air blown from the fan 40 flows into the heater unit 50 through this air intake 521, where it is heated by the heat generated by the heater 51 and becomes hot air. The hot air flows into the heater case 60 after passing around the outer circumference of the heater unit 50, and is then supplied into the roasting drum 70, where the coffee beans in the roasting drum 70 are roasted by being heated by the hot air.

[0021] The roasting drum 70 has a bottomed cylindrical shape with an open top and is made of a material with high thermal conductivity, such as aluminum. An insertion opening 61 is provided on the top surface of the heater case 60 into which the bottom of the roasting drum 70 is inserted. The roasting drum 70 is inserted through this opening 61, and a portion of its cylindrical lower part is housed inside the heater case 60. A flange 71 is formed at a predetermined position on the side wall of the roasting drum 70, extending outward. This flange 71 contacts the top surface of the heater case 60 to position it in the predetermined location. The flange is provided to seal the hot air passage with the top surface of the heater case 60, thereby forming a hot air passage.

[0022] The side of the roasting drum 70 is provided with hot air inlets 72 for taking in hot air generated by the heater unit 50. The hot air inlets 72 are slit-shaped and extend diagonally, and are arranged at regular intervals along the circumferential direction of the side. The hot air that passes through the hot air inlets 72 flows into the roasting drum 70 along this diagonal shape, generating a swirling flow within the roasting drum 70. The coffee beans are agitated by this swirling flow, and as they rotate inside the roasting drum 70, the moisture gradually evaporates, resulting in roasted coffee beans. In this way, the coffee beans are agitated by the swirling flow, allowing for uniform roasting in a short time without causing uneven roasting.

[0023] A heater case thermistor 62 is provided inside the heater case 60 as a first temperature detection means. The heater case thermistor 62 is a temperature sensor that detects the temperature of the hot air flowing into the roasting drum 70, and is located near the hot air inlet 72.

[0024] A roasting drum thermistor 73 is provided inside the roasting drum 70 as a second temperature detection means. The roasting drum thermistor 73 is a temperature sensor that detects the temperature of the coffee beans inside the roasting drum 70, and may directly detect the temperature of the coffee beans or detect the temperature of the air inside the roasting drum 70. In the roasting apparatus 1 of this embodiment, it is assumed that the coffee beans are loaded to approximately the height of the flange, and the roasting drum thermistor 73 is installed above the height of the coffee beans to detect the temperature of the air inside the roasting drum 70.

[0025] Roasting is performed by applying a heat-time curve called a roasting profile to the product being roasted. Figure 2 shows an example of a roasting profile. By heating coffee beans at a specific temperature, the sugars and amino acids contained in the beans undergo chemical reactions, adding flavors such as acidity, umami, and body. The main reactions in coffee beans include "hydrolysis," which produces acidity; the "Maillard reaction," in which sugars and amino acids combine to produce umami and body and create brown substances; and "caramelization," in which sugars react to produce bitter components in addition to umami and body. Each of these reactions is known to be activated in a specific temperature range.

[0026] Furthermore, the roasting device 1 has multiple roasting levels set, and the user can select a roasting level by operating a roasting level switch (not shown) located on the main unit 10, thereby performing roasting to the desired degree. Different profiles can be set depending on the roasting level.

[0027] The hot air that has passed through the coffee beans is discharged from an opening at the top of the roasting drum 70. The chaff that has peeled off the coffee beans during the roasting process is also discharged from the opening along with the hot air and collected in a chaff case 20 located above the main body 10. The chaff case 20 is provided with an exhaust port 21, and only the hot air after the chaff has been collected is discharged outside the device through this exhaust port 21.

[0028] The operation of the roasting apparatus 1 is controlled by the control device 80 (see Figure 3). The control device 80 controls the power supply to the heater 51 to maintain the temperature of the roasting drum 70 at the target temperature set in the roasting profile.

[0029] Because there are individual differences in the components that make up the roasting apparatus 1, the ease with which the temperature of the roasting drum 70 rises varies depending on the housing. In addition, the temperature of the place of use also affects how easily the temperature of the roasting drum 70 rises, so if conditions that make it easy for the temperature to rise are met, the temperature of the roasting drum 70 will easily exceed the target temperature, making it impossible to maintain a consistent quality of roasted products. Therefore, the control device 80 of this embodiment controls the power supply to the heater 51 using two temperature sensors, the heater case thermistor 62 and the drum thermistor 73.

[0030] Specifically, a reference temperature is set to a temperature a predetermined value lower than the target temperature, and the power supply to the heater 51 is controlled so that the temperature detected by the heater case thermistor 62 becomes the reference temperature. Then, a correction value is calculated from the target temperature and the temperature detected by the roasting drum thermistor 73, and the reference temperature is updated based on the correction value. After starting temperature control with a reference temperature set lower than the target temperature, the reference temperature is corrected from the temperature difference between the target temperature and the temperature inside the roasting drum 70, thereby preventing the temperature of the roasting drum 70 from exceeding the target temperature even if there are individual differences in the components. Furthermore, by controlling the power supply to the heater 51 with the heater case thermistor 62, which is the temperature sensor closest to the heater 51, temperature changes can be controlled linearly, so the temperature of the roasting drum 70 can be maintained at the target temperature regardless of individual differences in the equipment.

[0031] Figure 3 is a block diagram of the control device in the roasting device of the present embodiment. The control device 80 includes a profile storage unit 81, a reference temperature setting unit 82, a heater control unit 83, a correction value calculation unit 84, a reference temperature update unit 85, a timer unit 86, and a determination unit 87, and performs temperature control to control the temperature in the roasting pot 70 to the target temperature.

[0032] The profile storage unit 81 stores data on the target temperature Ta of the roasting pot 70 for realizing the roasting profile and the time for maintaining the target temperature Ta. The reference temperature setting unit 82 reads out the target temperature Ta of the roasting pot 70 stored in the profile storage unit 81, and sets a temperature that is lower than the target temperature Ta by a predetermined value as the reference temperature Ts. Note that the reference temperature may be stored in the profile storage unit 81. In this case, the reference temperature setting unit 82 reads out the reference temperature from the profile storage unit 81 and sets it as the reference temperature Ts.

[0033] The heater control unit 83 controls the energization of the heater 51 so that the temperature of the hot air detected by the heater case thermistor 62 becomes the reference temperature Ts. The heater 51 is configured to be energized either at 100% or 50%, for example, and the hot air temperature is maintained near the reference temperature Ts by switching the energization of the heater 51.

[0034] The correction value calculation unit 84 calculates a correction value Tc from the target temperature Ta stored in the profile storage unit 81 and the temperature Tm in the roasting pot 70 detected by the pot thermistor 73. The calculation of the correction value Tc is performed when the temperature in the roasting pot 70 is stable. The correction value Tc can be calculated by obtaining the difference between the target temperature Ta and the detected temperature Tm of the pot thermistor 73 and multiplying this difference by a coefficient K. The coefficient K may be a value that satisfies 0 < K < 1. Also, in the temperature control, K does not necessarily have to be a constant value. For example, the value of K may be different when a certain condition is satisfied and when it is not satisfied.

[0035] The reference temperature update unit 85 updates the reference temperature Ts based on the correction value Tc calculated by the correction value calculation unit 84. Specifically, the reference temperature update unit 85 updates the reference temperature Ts by adding the correction value Tc to the current reference temperature Ts. Once the reference temperature Ts is updated, the power supply to the heater 51 is controlled so that the temperature detected by the heater case thermistor 62 becomes the updated reference temperature Ts.

[0036] Note that the correction value Tc described above is not calculated for a predetermined time after the reference temperature Ts is updated. The timing unit 86 starts timing when the reference temperature Ts is updated and determines whether the time measured is equal to or greater than the predetermined time.

[0037] The determination unit 87 determines whether the temperature inside the roasting drum 70 has stabilized. Specifically, it samples the temperature Tm detected by the drum thermistor 73 at predetermined intervals. If there is little fluctuation in the sampled value, it is determined to be stable; if there is fluctuation, it is determined to be unstable. For example, if the temperature Tm detected by the drum thermistor 73 is sampled every second, it is determined to be stable if the difference between the maximum and minimum values ​​of 10 sampled values ​​is within 1°C.

[0038] Furthermore, if multiple target temperatures Ta are provided in the profile, the calculation of the correction value Tc may be omitted when the target temperature Ta is changed. For example, a correction start condition may be set, and the calculation of the correction value Tc may start when the condition is met. The correction start condition can be when a temperature above a certain level is continuously detected. Whether the correction start condition is met can be determined by the determination unit 87.

[0039] Next, the operation of the temperature control of the roasting apparatus in this embodiment will be explained using the flowchart in Figure 4.

[0040] When the control device 80 receives an instruction to start roasting, it starts temperature control. Once temperature control is started, the reference temperature setting unit 82 sets the reference temperature Ts (step 1). The reference temperature setting unit 82 reads the target temperature Ta of the roasting drum 70 stored in the profile storage unit 81 and sets the reference temperature Ts to a temperature that is a predetermined value lower than this target temperature Ta.

[0041] Once the reference temperature Ts is set, the heater control unit 83 starts energizing the heater 51 to heat the air flowing into the roasting drum 70. Then, it controls the energization of the heater 51 so that the temperature of the hot air detected by the heater case thermistor 62 reaches the reference temperature Ts (step 2).

[0042] When the heater 51 is energized, the timing unit 86 starts timing (step 3) and determines whether a predetermined time t1 has elapsed (step 4). If the predetermined time t1 has not elapsed, the determination is repeated while controlling the energization of the heater 51 until the predetermined time t1 has elapsed.

[0043] If a predetermined time t1 has elapsed (Yes in step 4), the determination unit 87 then determines whether the temperature Tm inside the roasting drum 70, as detected by the drum thermistor 73, has stabilized (step 5). If the temperature Tm detected by the drum thermistor 73 is rising or fluctuating up and down and is not stable (No in step 5), the power supply control of the heater 51 is continued and the system waits until the detected temperature Tm stabilizes. If it is determined that the detected temperature Tm has stabilized (Yes in step 5), the system proceeds to step 6.

[0044] The correction value calculation unit 84 calculates a correction value Tc from the target temperature Ta stored in the profile storage unit 81 and the temperature inside the roasting drum 70 detected by the drum thermistor 73 (step 6). The correction value Tc can be calculated by finding the difference between the target temperature Ta and the temperature Tm detected by the drum thermistor 73 and multiplying the difference by a coefficient K. In other words, the correction value Tc = K * (Ta - Tm).

[0045] The reference temperature update unit 85 updates the reference temperature Ts by adding a correction value Tc to the reference temperature Ts (step 7). When the reference temperature Ts is updated, the timing unit 86 resets (step 8). The process then returns to step 3, and the power supply to the heater 51 is controlled to achieve the updated reference temperature Ts.

[0046] In addition to the temperature control shown in Figure 4, the control unit also performs termination control to determine when the temperature control is finished. If the termination control signals the end of the temperature control, the flowchart ends. Subsequently, if a new target temperature is set, the temperature control is executed again.

[0047] Figure 5 is a graph showing the changes in the reference temperature and the temperature inside the roasting drum during temperature control. The graph shows the result when the correction value Tc is calculated using a coefficient K=0.5 (=1 / 2), with the reference temperature Ts shown as a dashed line and the temperature Tm detected by the drum thermistor 73 shown as a solid line. At time 0, the reference temperature Ts is set and the heater 51 is powered on.

[0048] At time a, the temperature Tm detected by the boiler thermistor 73 stabilized, so the first temperature correction was performed. If the difference between the target temperature Ta and the temperature Tm detected by the boiler thermistor 73 is Da (black arrow), then the correction value Tc is Da / 2 (white arrow), so the new reference temperature Ts is the original reference temperature Ts plus Da / 2.

[0049] Next, at time b, the temperature of the roasting drum stabilizes, so a second temperature correction is performed. If Db is the difference between the target temperature Ta and the temperature Tm detected by the drum thermistor 73, then the correction value Tc is Db / 2, and the new reference temperature Ts is the original reference temperature Ts plus Db / 2. From here on, temperature correction is performed similarly at times c and d, and the temperature Tm detected by the drum thermistor 73 gradually approaches the target temperature Ta. Even if the temperature Tm detected by the drum thermistor 73 becomes higher than the reference temperature Ts during the heating of the roasting drum 70, controlling the heater 51 at that point can prevent the roasting drum 70 from exceeding the target temperature Ta.

[0050] Thus, in the roasting apparatus 1 of the present embodiment, by setting the reference temperature Ts serving as the reference for temperature control to be lower than the target temperature Ta, the temperature of the roasting pot 70 can be gradually increased. Therefore, even in a housing where the temperature tends to rise, it is possible to suppress the temperature of the roasting pot 70 from exceeding the target temperature Ta. And, of the two temperature sensors, by controlling the energization of the heater 51 with the heater case thermistor 62 close to the heater 51, the temperature change can be linearly controlled. Therefore, the temperature of the roasting pot 70 can be maintained at the target temperature Ta regardless of the individual differences of the housing.

[0051] Further, after setting or updating the reference temperature Ts, by calculating the correction value Tc when the detected temperature Tm of the pot thermistor 73 is stable, unnecessary correction is prevented, and the temperature of the roasting pot 70 can be more reliably maintained at the target temperature Ta.

[0052] Also, even if the reference temperature Ts is set or updated, the temperature of the roasting pot 70 does not immediately rise, and a time lag occurs until the temperature rises. If this time lag is erroneously detected as the temperature being stable, there is a possibility that the heater 51 cannot be appropriately controlled. Therefore, by not calculating the correction value Tc for a predetermined time t1, such an erroneous detection can be prevented.

[0053] Also, the correction value Tc is calculated by multiplying the difference between the target temperature Ta and the detected temperature Tm of the pot thermistor by a coefficient K (0 < K < 1), and the reference temperature Ts is updated by adding the correction value Tc to the reference temperature Ts. Thereby, the correction value Tc can be appropriately set, and the temperature of the roasting pot 70 can be more reliably maintained at the target temperature Ta.

Explanation of Reference Numerals

[0054] 40 Fan 51 Heater 62 Heater Case Thermistor (First Temperature Detection Means) 70 Roasting Pot 73 Pot Thermistor (Second Temperature Detection Means) 80 Control Device

Claims

1. A fan that generates airflow, A heater that heats the air, A roasting kettle that takes in heated air to roast the roasted items, A first temperature detection means for detecting the temperature of the air flowing into the roasting kettle, A second temperature detection means for detecting the temperature inside the roasting kettle, The roasting machine includes a control device that performs temperature control to control the temperature inside the roasting machine to a target temperature. The control device, in the temperature control, sets a reference temperature that is a predetermined value lower than the target temperature, controls the power supply to the heater so that the temperature detected by the first temperature detection means becomes the reference temperature, calculates the difference between the target temperature and the temperature detected by the second temperature detection means, calculates a correction value from the temperature difference, and updates the reference temperature based on the correction value.

2. The roasting apparatus according to claim 1, wherein the control device calculates the correction value when it determines that the temperature detected by the second temperature detection means has stabilized after setting or updating the reference temperature.

3. The roasting apparatus according to claim 2, wherein the control device does not calculate the correction value for a predetermined time after setting or updating the reference temperature.

4. The roasting apparatus according to any one of claims 1 to 3, wherein the control device calculates the correction value by multiplying the difference between the target temperature and the temperature detected by the second temperature detection means by a coefficient K (0 < K < 1), and updates the reference temperature by adding the correction value to the reference temperature.

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