Roasting system and roasting method

Abstract

To provide a roasting system using bio-pellets to acquire stable combustion and capable of controlling a hot air temperature to a target level.SOLUTION: There is provided a roasting system that burns bio-pellets in a pellet burner 2 to generate hot air, sends the hot air to a roaster 3 and roasts coffee beans. The pellet burner 2 is a hearth type that burns the bio-pellets in a furnace body 2A. The roasting system includes a first path 4 for supplying hot air from the furnace body 2A of the pellet burner 2 to the roaster 3, a second path 5 whose one end is connected to the first path 4 and whose other end is opened to the outside, and an opening / closing damper 6 provided in the second path 5.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a roasting system and a roasting method, and particularly to a roasting system and a roasting method using solid biofuel.

Background Art

[0002] In recent years, the consumption of coffee beverages has increased significantly as a preferred beverage, and accordingly, the consumption of coffee beans has also increased. Therefore, a large amount of coffee extract residue is generated after coffee liquid extraction. This is also a similar problem in tea leaves, wheat, and other food ingredients.

[0003] However, only a small part is effectively utilized, and most of it is currently discarded as general waste or industrial waste and incinerated.

[0004] In addition, in order to effectively utilize coffee extract residue, a coffee liquid extraction system has been proposed that uses the bio-coke technology to convert coffee extract residue into bio-coke and uses it as a heat source (see, for example, Patent Document 1).

[0005] Such solid biofuel has poor ignitability and combustion stability, and it is difficult to use it as a heat source for hot air roasting. In addition, due to its shape, continuous fuel supply is not possible, so only manual feeding can be applied. Therefore, it is considered to process it into small biofuels such as coffee pellets that are easy to use as fuel and use coffee extract residue as a heat source for hot air roasting.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In the case of a small size, the gun type can also be used. Therefore, the inventors used a solid biofuel such as coffee pellets as fuel in hot air roasting and used an integrated and small gun type burner. As a result, the combustion responsiveness was lower than when using gas as fuel, and it was difficult to control stable combustion. This is considered because in the case of a gun type burner, there is no pilot flame, so the combustion is unstable.

[0008] Therefore, when the burner was changed from the gun type to a hearth type with a pilot flame, stable combustion was confirmed, and it was found that the hot air temperature can be controlled by discharging a part of the hot air or introducing cold air and controlling their balance.

[0009] An object of the present invention is to provide a roasting system and a roasting method that can obtain stable combustion using a bio-pellet and can control the hot air temperature to a target value.

Means for Solving the Problems

[0010] A roasting system according to one aspect of the present invention is a roasting system for roasting foodstuffs such as coffee beans and nuts, and includes a roaster for roasting foodstuffs, a hot air generating means for generating hot air to be supplied to the roaster, a first passage for supplying hot air from the furnace body of the hot air generating means to the roaster, a second passage having one end connected to the first passage or the hot air generating means and the other end open to the outside, a first on-off valve provided in the first passage, and a second on-off valve provided in the second passage. The hot air generating means generates hot air by burning solid biofuel in the furnace body, and opens and closes the first on-off valve and the second on-off valve in accordance with the temperature difference from the target temperature of the roaster to adjust the temperature of the hot air supplied to the roaster.

[0011] In this way, when the hot air from the hot air generating means is supplied to the roaster, a part of it can be discharged through the second passage, so that temperature control with better responsiveness than controlling the hot air temperature by fire power control in the hot air generating means itself becomes possible.

[0012] In addition, since hot air can be generated using solid biofuel, it contributes to energy savings. Also, although the hot air generation means for solid biofuel has inferior responsiveness compared to gas or burners, by having the above-described configuration, temperature control with excellent responsiveness is possible.

[0013] In this case, it is desirable that the first passage is provided with auxiliary air introduction means for introducing outside air into the first passage, and the amount of outside air introduced by the auxiliary air introduction means is controlled according to the temperature difference from the target temperature of the roaster, and the temperature of the hot air supplied to the roaster is further adjusted. As a result, in addition to partial discharge through the second passage, outside air (cool air) can be introduced by the auxiliary air introduction means, enabling finer temperature control with more excellent responsiveness.

[0014] An exhaust fan is provided in the second passage, a third passage for exhausting the hot air used for roasting in the roaster to the outside of the roaster is connected, and the third passage is connected to the second passage on the upstream side of the exhaust fan. As a result, the hot air can be stably drawn in from the first passage by the exhaust fan, the bio-combustion can be stabilized, and the exhaust used for roasting can be discharged to the outside together with the exhaust from the hot air generation means through the second passage.

[0015] In addition, a configuration is formed in which a first passage for supplying hot air from the hot air generation means to the roaster, a second passage connected thereto and provided with an exhaust fan, and a third passage for sending the exhaust from the roaster to the second passage are connected so that the passage from the hot air generation means through the roaster to the exhaust fan is connected. As a result, a one-to-one correspondence can be established in which the hot air generated by the hot air generation means is pulled by one exhaust fan, so that the introduced air volume of the hot air generation means can be stabilized, and thus the combustion of the hot air generation means can be stabilized.

[0016] In addition, since the high-temperature exhaust from the hot air generating means and the exhaust from the roaster after roasting are discharged through the same passage, the dirt such as oil adhering in the passage caused by the exhaust after roasting can be removed by the high-temperature exhaust from the hot air generating means, and the so-called thermal cleaning effect can be obtained.

[0017] In addition, the other end of the second passage is open to the outside through a cyclone and a smoke elimination device. Thereby, the exhaust after roasting and the like can be cleaned and discharged to the outside.

[0018] It is desirable that the roaster is provided with auxiliary hot air generating means for generating hot air by gas combustion. Thereby, during the heating period, by using the auxiliary hot air generating means, the time required for heating can be shortened, and finer temperature adjustment can be achieved during roasting. Also, for example, when an unexpected situation occurs such as a malfunction in the hot air generating means, roasting can be continued.

[0019] It is desirable that the roaster is provided with water supply means for supplying cooling water. In this way, the color of the ingredients such as coffee beans after roasting can be easily adjusted. Also, the ingredients and the roaster can be cooled.

[0020] It is desirable that a heat exchanger is provided in the middle of the second passage or the third passage. Thereby, the exhaust heat from the exhaust after roasting and the like can be effectively utilized.

[0021] It is desirable that the solid biofuel is coffee pellets, or wood pellets, or a mixture of coffee pellets and wood pellets. Thereby, coffee husks and the like that are usually discarded can be effectively utilized as bio pellets. Also, by using wood pellets or mixing wood pellets, the ignitability can be improved.

[0022] Further, in the roasting system, instead of the hot air generating means generating hot air by burning solid biofuel in the furnace body, an electric furnace is used, and the electric furnace includes an electric heater and generates hot air using the electric heater as a heat source.

[0023] In this way, when the hot air from the electric furnace is supplied to the roaster, a part of it can be discharged through the second passage, so that temperature control with better responsiveness than controlling the temperature of the hot air by controlling the fire power in the electric furnace becomes possible. Further, like the hot air generating means using the solid biofuel described above, the electric heater has a very slow responsiveness in controlling the amount of heat and is not good at fine control compared to gas and oil. Therefore, with the above-described configuration, excellent responsiveness temperature control is possible even when using an electric heater.

[0024] A roasting method according to one aspect of the present invention is a roasting method for roasting food materials such as coffee beans and nuts using a roasting system including a roaster for roasting food materials, a hot air generating means provided with a furnace body for generating hot air in the furnace body, a first passage connected to the hot air generating means and the roaster, a second passage having one end connected to the first passage or the hot air generating means and the other end open to the outside, and an opening / closing device provided in the first passage and the second passage. The roasting method includes a hot air generating step of generating hot air by burning solid biofuel in the furnace body, a hot air supplying step of supplying the generated hot air to the roaster through the first passage, and a roasting step of roasting the food materials using the hot air in the roaster, and is characterized by controlling the opening and closing of the first and second opening / closing devices according to the temperature difference from the target temperature of the roaster to adjust the temperature of the hot air supplied to the roaster.

[0025] In this way, when hot air from the hot air generating means is supplied to the roaster, by opening and closing the first and second opening and closing devices to partially discharge it through the second passage, etc., temperature control with better responsiveness than controlling the temperature of the hot air by controlling the heating power of the hot air generating means itself becomes possible. Here, this opening and closing device includes, for example, an opening and closing damper, etc., and includes those that can adjust the opening ratio in addition to fully opening and closing, and those that can be adjusted are preferred.

[0026] Here, when the inventors repeatedly tested various methods in the development of the roasting method, they felt that the flavor of the food after roasting was being impaired. When they investigated the cause, they considered the possibility that the hot air sent from the hot air generating means to the roaster contained soot, and further repeated tests of various methods, and found a roasting method having the following configuration.

[0027] The roasting method is characterized by further comprising a warming step of discharging the hot air generated in the furnace body to the outside through the second passage with the first opening and closing device closed and the second opening and closing device open prior to the hot air supply step.

[0028] Here, regarding the cause of flavor impairment, incomplete combustion that discharges a lot of soot occurs from the ignition of the solid biofuel in the hot air generating means until complete combustion. And when that hot air is directly supplied to the roaster, it was found that soot adheres to the piping, inside the cylinder, and ultimately to the food to be roasted, impairing the flavor.

[0029] Then, in the roasting method having the above-described configuration, specifically, from the ignition of the solid biofuel until complete combustion, with the first opening / closing device closed and the second opening / closing device open, the hot air generated in the furnace body is discharged to the outside through the second passage. That is, after passing through a warming process in which hot air containing soot is not supplied to the roaster, by supplying hot air to the roaster, it is possible to prevent deterioration of the flavor due to soot. Therefore, with this configuration, hot air at a desired temperature can be supplied to the roaster after it is generated, and it is not necessary to stop the hot air supply means that has been started during operation, which is safe, and the adverse effect on the flavor due to soot can be suppressed.

[0030] Also, it is characterized in that the hot air generating means is not stopped from the start of generation of hot air in the furnace body until the end of roasting of the food ingredients, including the warming process. With this configuration, it is safe to operate the hot air generating means without stopping it from the start of operation until the end of roasting.

[0031] This is because the hot air generating means burns bio-pellets to generate hot air, and if the hot air generating means is inadvertently stopped halfway, there is a risk of backfire with unburned bio-pellets or the like. Therefore, it is desirable to stop the combustion of the bio-pellets and stop the hot air generating means after roasting is completed. In addition, it is more desirable not to stop the hot air generating means until the combustion of the bio-pellets remaining in the furnace body subsides after the roasting of coffee beans is completed.

[0032] Also, it is characterized in that the inside of the furnace body is maintained at a negative pressure from the start of generation of hot air in the furnace body until the end of roasting of the coffee beans, including the warming process, until the hot air generating means is stopped. According to this configuration, when the inside of the furnace body becomes positive pressure, there is a risk that heat will flow backward to the fuel supply section where there is unused bio-pellet and cause backfire, but this can be prevented, enabling safe operation.

[0033] Further, the roasting system is provided with auxiliary air introduction means for introducing outside air into the first passage. In the hot air supply step, according to the temperature difference from the target temperature of the roaster, the amount of outside air introduced by the auxiliary air introduction means is controlled and supplied to the roaster to further adjust the temperature of the hot air. As a result, in addition to partial discharge through the second passage, outside air (cool air) can be introduced by the auxiliary air introduction means, enabling finer temperature control with better responsiveness.

[0034] Further, an exhaust fan is provided in the second passage of the roasting system, and a third passage for exhausting the hot air used for roasting from the roaster to the outside of the roaster is connected. The third passage is connected to the second passage on the upstream side of the exhaust fan. In the roasting step, the hot air used for roasting is exhausted to the outside through the third passage and the second passage from the roaster.

[0035] As a result, the hot air can be stably drawn in from the first passage by the exhaust fan, the combustion can be stabilized, and the exhaust used for roasting can be discharged to the outside together with the exhaust by the hot air generation means through the second passage.

[0036] In addition, since the high-temperature exhaust by the hot air generation means and the exhaust from the roaster after roasting are discharged through the same passage, the so-called thermal cleaning effect of removing dirt such as oil adhering in the passage caused by the exhaust after roasting by the high-temperature exhaust of the hot air generation means can be obtained.

[0037] Further, the other end of the second passage is open to the outside through a cyclone and a smoke elimination device. In the roasting step, the hot air used for roasting is exhausted to the outside through the third passage, the second passage, the cyclone, and the smoke elimination device from the roaster. As a result, the hot air after being used for roasting can be discharged to the outside in a clean state, which is environmentally friendly.

[0038] In addition, the roasting system is provided with auxiliary hot air generation means for generating hot air by gas combustion in the roaster, and in the hot air supply step, according to the temperature difference from the target temperature of the roaster, the amount of hot air introduced by the auxiliary hot air generation means is controlled and supplied to the roaster to further adjust the temperature of the hot air.

[0039] Thereby, during the heating period, by using the auxiliary hot air generation means, the time required for heating can be shortened, and during roasting, finer temperature adjustment becomes possible. Further, for example, when an unexpected situation occurs such as a malfunction in the hot air generation means, it is also possible to continue roasting.

[0040] In addition, the roasting system is provided with water supply means for supplying cooling water to the roaster, and after the completion of the roasting step, it further includes a water injection step by the water supply means. In this way, the color of the roasted coffee beans can be easily adjusted. Also, the coffee beans and the roaster can be cooled.

[0041] In addition, the roasting system is provided with a heat exchanger in the middle of the second passage or the third passage, and the heat energy of the exhaust gas flowing through the second passage or the third passage is recovered by the heat exchanger. Thereby, the exhaust heat from the exhaust gas after roasting and the like can be effectively utilized. Further, this heat exchanger can be arranged, for example, so as to straddle the second passage or the third passage and the piping leading to the hot air generation means, so that the heat energy of the exhaust gas in the second or third passage can be used for hot air generation.

[0042] In addition, in the hot air generation step, the pellets burned in the furnace body are coffee pellets or bio-pellets that are a mixture of coffee pellets and wood pellets. Thereby, coffee grounds and the like that are usually discarded can be effectively utilized as bio-pellets. Also, by mixing wood pellets, it is possible to improve the ignitability.

[0043] Further, in the roasting system, the hot air generating means is an electric furnace equipped with an electric heater, and the hot air generating step is a step of generating hot air using the electric heater as a heat source by the electric furnace instead of a step of generating hot air by burning biofuel in the furnace body. According to the roasting method having this configuration, even when an electric heater with inferior responsiveness compared to gas, burner, etc. is used, temperature control with excellent responsiveness can be achieved.

Advantages of the Invention

[0044] In the present invention, when supplying hot air from the hot air generating means to the roaster, a part of the hot air can be discharged through the second passage. Therefore, compared to controlling the temperature of the hot air by controlling the firing power of the hot air generating means itself, temperature control of the hot air with excellent responsiveness becomes possible, and stable combustion can be obtained.

Brief Description of the Drawings

[0045]

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Fig. 7

Fig. 8

Fig. 9

Fig. 10

Fig. 11

Mode for Carrying Out the Invention

[0046] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an overall view showing the schematic configuration of a roasting system according to the present invention, showing the case where the pellet burner (hot air generating means) is in a heating state.

[0047] In FIG. 1, reference numeral 1 denotes a roasting system that uses coffee pellets (bio pellets) as fuel, a hearth-type pellet burner 2 (hot air generating means) that burns the coffee pellets in a furnace body 2A to generate hot air, a roaster 3 (roaster) that roasts coffee beans using the hot air, a first passage 4 that supplies hot air from the pellet burner 2 to the roaster 3, a second passage 5 having one end connected to the first passage 4, and an opening / closing damper 6 provided in the second passage 5.

[0048] A third passage 7 upstream of the exhaust fan 8 is connected to the second passage 5, and the exhaust of the hot air used for roasting is released to the outside through the third passage 7, the exhaust fan 8, the cyclone 9, and the smoke elimination equipment 10. An opening / closing damper 12 that is opened and closed by an actuator is provided in the first passage 4 on the downstream side of the portion where the second passage 5 branches. Then, the opening / closing damper 6 is controlled to open and close according to the temperature difference from the target temperature of the roaster 3, and the temperature of the hot air supplied to the roaster 3 is adjusted.

[0049] The second passage 5 has an exhaust fan 8 and a cyclone 9 connected midway to the external exhaust port, and a deodorizing device fan (not shown) of the smoke elimination facility 10 is connected to the downstream side of the cyclone 9. Further, an opening / closing damper 11a that opens during abnormal stop of the smoke elimination facility 10 or the like is provided in a passage 11 connecting the cyclone 9 and the smoke elimination facility 10.

[0050] Also, the first passage 4 has a passage 14 having an exhaust fan 13 connected immediately downstream of the furnace body 2, and opening / closing dampers 15A and 15B are provided on the downstream sides of the respective connection portions. These are interlocked and opened / closed by one actuator. Only during a power failure or a cooling operation, the opening / closing damper 15A is opened and the opening / closing damper 15B is closed, and when the exhaust fan 13 is driven, exhaust is performed.

[0051] The first passage 4 is connected to the roaster 3 via a large-diameter hot air introduction part 16. An auxiliary air introduction means 17 for introducing outside air is provided in the hot air introduction part 16 to adjust the temperature of the hot air. As an example, an electric fan is used for the auxiliary air introduction means 17 of the present embodiment.

[0052] The adjustment of the hot air temperature by the auxiliary air introduction means 17 is such that the outside air introduction amount of the auxiliary air introduction means 17 is controlled according to the temperature difference from the target temperature of the roaster 3, and the temperature of the hot air supplied to the roaster 3 is adjusted to be lowered. And the air volume introduced by the auxiliary air introduction means 17 is controlled by an inverter.

[0053] Note that the control of the introduced air volume is not limited to an inverter, and it is also possible to provide a motor damper at the intake port and adjust it by the control. By not using an inverter, the cost can be suppressed.

[0054] In addition, the auxiliary air introduction means 17 is also used for purposes other than the above-described roles. For example, at the final finishing stage of roasting, in order to store heat in the roaster and the roasted coffee beans, heat is blocked and even without applying heat, they are continuously heated by that stored heat, and in a situation where it is difficult to effectively perform braking control of heating, the auxiliary air introduction means 17 has a role of taking in outside air to apply braking.

[0055] In addition, the hot air introduction section 16 is also provided with auxiliary hot air generation means for auxiliary generation of hot air by gas combustion when heating with warm air or the like. In the present embodiment, as an example, a gas burner 18 is used as the auxiliary air introduction means. An on-off valve 18a is provided in the air introduction passage of the gas burner 18 to block cold air that leaks when the gas burner is not in use.

[0056] The roaster 3 is provided with a rotatable rotary cylinder 20 that accommodates coffee beans (green beans) inside and roasts them within the furnace body 19. During roasting, the rotary cylinder 20 is rotationally driven by a motor while hot air is introduced. The furnace body 19 is connected to the third passage 7 via a passage 22 having an exhaust bypass damper 21 that is opened and closed by an actuator.

[0057] An exhaust damper 23 that is opened and closed by an actuator is also provided upstream of the third passage 7 at this connection portion. The exhaust damper 23 can be used to block leaks when the gas burner 18 is not in use without performing temperature control of the hot air.

[0058] Here, the uses of the exhaust damper 23 and the exhaust bypass damper 21 will be described. During roasting, etc., the exhaust damper 23 is opened, and the exhaust from the roaster 3 is exhausted to the outside through the second passage 5 via the third passage 7. On the other hand, when opening the raw material hopper damper 26, the exhaust damper 23 is closed and the exhaust bypass damper 21 is opened to prevent the raw material from being blown downstream (towards the third passage 7). Similarly, during quenching with water, the exhaust bypass damper 21 is opened to release hot air to prevent the raw material from being blown away. During quenching, the internal pressure in the rotary cylinder 20 increases due to the generated water vapor, so this is to prevent the raw material from being expelled outside.

[0059] Also, regarding the exhaust bypass damper 21, when the front cover 24 described later is open and cold outside air tries to enter through the front cover 24 and flow into the third passage 7 through the exhaust damper 23, at this time, by opening the exhaust bypass damper 21, the inflow of cold outside air into the third passage 7 can be suppressed, and a flow can be created such that the hot air from the hot air introduction part 16 by the gas burner 18 flows into the third passage 7 from the exhaust bypass damper 21. By doing so, it is possible to suppress the combustibility of the gas burner 18 and the fuel consumption of the smoke elimination equipment 10 when cold air flows into the third passage 7.

[0060] Note that when closing the above-described exhaust damper 23, it is configured not to be fully closed. This is because if the timing is bad when roasting using the gas burner 18, and the gas burner 18 misfires while the exhaust damper 23 is completely closed, there is a risk of combustion gas filling the furnace body 19 and ignition, so the exhaust damper 23 is not allowed to be fully closed.

[0061] Also, as shown in FIG. 2, the rotary cylinder 20 has stirring blades 20B irregularly provided inside a cylindrical main body 20A.

[0062] As shown in Fig. 1, the rotating cylinder 20 is provided with a front lid 24 that is opened and closed by a slide movement driven by an actuator. This front lid 24 includes a cylindrical input portion 24a into which raw materials are input. This input portion 24a is detachably connected to the downstream end of the third passage 7, and near the downstream end of this third passage 7, an input port 25a of a hopper portion 25 for storing raw materials is provided.

[0063] An ingredient hopper damper 26 that is opened and closed by an actuator is provided at the input port 25a and is opened when raw materials are input. For the rotating cylinder 20, water supply means 27 for supplying cooling water is provided for adjusting the color of roasted coffee beans and the like. It can also be used to deal with troubles such as during heating or power outages on the roaster 3 side. Further, it can also be used for rapidly reducing the hot air temperature as the hot air control of the roaster 3.

[0064] According to the above system, by controlling the balance among the amount of hot air supplied to the roaster 3 through the first passage 4, the amount of air discharged through the second passage 5, and further the amount of outside air (cool air) introduced by the auxiliary air introduction means 17, it becomes possible to control the temperature of hot air with good responsiveness, and once combustion starts, stable combustion is ensured. That is, when fire power is required, it is in the state shown in Fig. 3, during roasting, it is in the state shown in Fig. 4, and when fire power is not required, it is in the state shown in Fig. 5.

[0065] By the way, when the pressure inside the furnace of the pellet burner 2 becomes positive pressure, heat flows backward to the fuel supply part. On the other hand, if the pressure inside the furnace is made too negative, the supply of air becomes excessive, the inside of the furnace is cooled, and it becomes an obstacle to combustion, so that point is considered. In addition, in order to enable more detailed control, in addition to the second passage 5, it is also possible to provide a passage 43 (circulation passage) having opening and closing dampers 41, 42. In the event that the pellet burner 2 cannot be used, it is also possible to roast only with the gas burner 18, and in that case, roasting is performed using the opening and closing dampers 41, 42, and the passage 43 (circulation passage).

[0066] The responsiveness of combustion is greatly affected by the control of the pellet supply amount, and a time lag of several minutes occurs before it is reflected in the temperature. Therefore, by controlling the balance between introducing all the hot air into the roaster 3 and exhausting a part through the second passage 5, the influence of the time lag can be minimized.

[0067] After the roasting is completed, the front lid 24 is opened (see Fig. 6), and the holding frame 20a at the end of the rotary cylinder 20 is moved by the actuator, and the roasted coffee beans are moved to the upper part of the cooling tank 28 adjacent to the roaster 3 (see Fig. 7). At this time, outside air (indoor air) is introduced and cooled through the fourth passage 30 having the intake fan 29 (see Fig. 8).

[0068] The air after this cooling is exhausted through the fifth passage 34 having the on-off damper 31, the exhaust fan 32, and the cyclone 33. Coffee beans (raw beans) as raw materials are introduced, for example, within 60 seconds from the start of this cooling, and the next roasting is started after 60 seconds from the start of cooling. Note that this 60 - second time is just an example and is not limited to this. Also, if the input conditions are not met due to raw material supply, the temperature inside the furnace body 19, etc., it will be in a standby state.

[0069] After cooling, in the cooling tank 28, the suction damper 35 is opened (see Fig. 9), and the roasted coffee beans after cooling are transported to the storage tank 37 through the suction passage 36 and stored. The storage tank 37 is provided with a product discharge damper 37a and a level gauge 37b. And the suction air is discharged to the downstream part of the exhaust fan 32 in the fifth passage 34 through the sixth passage 39 having the on-off damper 38 opened and closed by the actuator.

[0070] And in addition to the air volume control (opening and closing control of the on-off damper 6) of introducing the hot air from the pellet burner 2 directly into the roaster 3 or exhausting a part through the second passage 5, by controlling the introduced air volume of outside air (cold air) by the auxiliary air introduction means 17, temperature control with better responsiveness than that controlled by the conventional gas burner's fire power control is realized.

[0071] In addition, in the configuration of a gas burner and an auxiliary blower used in a conventional general roasting machine, when it is desired to suddenly lower the hot air supplied to the roaster, the method of reducing the burner output to the weakest and increasing the air volume or shutting off the burner and using only the blower has been adopted. However, in the former case, it is impossible to reduce the output below the limit of the burner turndown ratio and only cold air can be sent, and in the latter case, since it takes time to reignite the burner, it has been difficult to apply the appropriate timing. On the other hand, in the roasting system of the present embodiment, since the opening and closing damper (opening and closing damper) is responsible for shutting off the hot air and the blower is responsible for the air supply, the above-described conventional problems can be solved, and thereby the safety is improved even when performing dark roasting.

[0072] In addition, since the exhaust fan 8 is arranged in the second passage 5 for exhausting a part of the hot air, a part of the hot air can be exhausted smoothly without impairing the stable combustion of the pellet burner 2.

[0073] Since the excess hot air supplied from the pellet burner 2 is exhausted through the second passage 5, it is possible to exhaust the hot air to the subsequent smoke removal facility 10 while it is still hot, so that the fuel consumption of the smoke removal facility 10 can also be suppressed.

[0074] And, in addition to exhausting the excess hot air supplied from the pellet burner 2 through the second passage 5, the exhaust of the roaster 3 also passes through the third passage 7 and then through the second passage 5. Therefore, the so-called thermal cleaning effect of burning and removing the dirt containing the coffee oil adhering to the passage due to the exhaust of the roaster 3 by the hot air from the pellet burner 2 can be obtained. In addition, this removes the risk of in-duct fire.

[0075] Subsequently, the basic control of the furnace temperature of the roaster 3 and the basic control of the exhaust bypass damper 21 will be described below.

[0076] (Basic control of the furnace temperature of the roaster 3) The furnace temperature set value of the pellet burner 2 is set on the operation panel on the roaster 3 side. After the temperature has risen to the set temperature, which is the furnace temperature set value, a certain amount of hot air generated by the pellet burner 2 is supplied to the first passage 4, and the hot air distributed to an appropriate air volume by the control of the on-off dampers 6 and 12 is supplied into the furnace of the roaster 3. At that time, the hot air is mixed with the air introduced from the auxiliary air introduction means 17, and the temperature of the hot air is controlled to an appropriate temperature.

[0077] The introduction amount from the auxiliary air introduction means 17 is targeted at the set temperature, the opening degree of the on-off damper 17a of the auxiliary air introduction means 17 is PID-controlled, and the temperature control of the furnace temperature is performed.

[0078] Then, as shown in FIG. 10, the operation power supply is turned on (step S1) and starts. Then, the roaster button is turned on (step S2), the preheating button is turned on (step S3), the auxiliary hot air generating means (gas burner 18) is ignited (step S4), it is confirmed whether the preheating completion condition is OK (step S5), and it shifts to the gas burner standby setting (step S6).

[0079] On the other hand, when the roaster button is turned on, it is selected whether to automatically connect the coffee fuel burner (pellet burner 2) (step S7). If it is ON, the temperature inside the coffee fuel burner furnace is set to be higher (step S8). If it is OFF, the burner connection button is long-pressed (step S9), and a coffee fuel burner connection command is issued (step S10).

[0080] Then, the auxiliary hot air generating means (gas burner 18) is extinguished (step S11), and the burner intake damper (on-off valve 18a) is closed (step S12). On the other hand, the burner damper (on-off damper 12) is opened (step S13), the continuous operation button is turned on (step S14), and the preparation is completed (step S15).

[0081] (Basic control of the exhaust bypass damper 21) In addition to controlling the furnace temperature of the roaster 3, the exhaust bypass damper 21 is controlled to open and close according to the state of the roaster 3. That is, (i) it is closed during the input standby, (ii) it is open during the raw material input, (iii) it is open 3°C before the finish, (iv) it is open during the water injection, (v) it is closed when the front cover is open, and (vi) it is closed during the after purge. However, like other on-off dampers, it is driven to open and close by the control of the actuator.

[0082] Then, as shown in FIG. 11, when the preparation is completed and ON starts (step S21), it is determined whether the supply of green coffee is completed (step S22). If it is ON, the temperature rise is started (step S23). If it is OFF, the input standby state is set (step S24). At this time, the exhaust bypass damper 21 is closed.

[0083] When the temperature rise is started, the set furnace temperature is changed to the temperature rise set value (step S25), the input temperature is set to the appropriate temperature (step S26), and the input start (roasting start) is performed (step S27). Here, the exhaust bypass damper 21 is open and the exhaust damper 23 is closed.

[0084] The raw material hopper damper 26 is opened (step S28), the raw material hopper level meter 25b is set to OFF (step S29), and the raw material hopper damper 26 is closed (step S30). Here, the exhaust bypass damper 21 is closed and the exhaust damper 23 is opened. During roasting, the furnace temperature is controlled by the basic operation.

[0085] When the finish minus 3°C temperature is reached (the finish temperature - 3°C is achieved) (step S31), the exhaust bypass damper 21 is opened. Subsequently, it is determined whether the finish temperature is reached or the discharge button is turned ON (step S32).

[0086] The exhaust bypass damper 21 is opened, and water injection by the water supply means 27 is started (step S33). When the water injection amount is OK (step S34), the waiting time after water injection is increased (step S35). The exhaust bypass damper 21 is opened, the front lid 24 is opened, and the discharge of roasted beans is started (step S36). The opening time of the front lid 24 is increased (step S37), the exhaust bypass damper 21 is closed (step S38), and the front lid 24 is closed.

[0087] It is determined whether or not to stop the roasting cycle (step S39). If it is ON, the cooling and suction process ends (step S40), the automatic operation ends (step S41), and the exhaust bypass damper 21 is closed and after-purge is started (step S42). On the other hand, if it is OFF, without stopping the cycle, it returns to the start of preparation completed ON (step S21).

[0088] Note that the pellet burner 2 operates without stopping from the start of combustion of the bio-pellet to the end of roasting, and is always controlled so that the inside of the furnace becomes negative pressure. Also, when stopping the pellet burner 2 after roasting, in order to keep the inside of the furnace at negative pressure until the combustion of the bio-pellet subsides, the opening / closing damper 6 of the second passage 5 is opened or the like so that hot air is exhausted.

[0089] Also, considering that it may take several days to stop the combustion of the pellet burner 2, in that case, the opening / closing dampers 6 and 12 can be closed, and cold outside air can be taken in from the auxiliary air introduction means 17 to cool the roaster 3 first.

[0090] As described above, the embodiments of the present invention have been described with reference to the drawings. However, various additions, changes, or deletions are possible without departing from the spirit of the present invention.

[0091] ·The opening / closing control of the opening / closing damper 6 and the control of the outside air introduction amount of the auxiliary air introduction means 17 can be achieved by driving the actuator through manual operation. However, a temperature sensor for detecting the furnace temperature may be provided in the roaster 3. By receiving the signal from the temperature sensor and according to the temperature difference from the set temperature set on the operation panel on the roaster 3 side, the opening / closing control of the opening / closing damper 6 and the control of the outside air introduction amount of the auxiliary air introduction means 17 can also be performed.

[0092] ·In order to avoid the influence of fly ash from the pellet burner 2, it is possible to provide a cyclone downstream of the pellet burner 2.

[0093] ·It is also possible to provide a heat exchanger in the middle of the second passage 5 or the third passage 7 to effectively utilize the exhaust heat.

[0094] ·In the roaster 3, in order to improve the fuel consumption, it is possible to circulate and use a part of the hot air to be exhausted.

[0095] ·Instead of the hot air generation means for burning solid biofuel to generate hot air with the pellet burner 2, it is also possible to use an electric furnace equipped with an electric heater. Different from the gas or oil, the electric heater has a very slow responsiveness in heat quantity control and is not good at fine control. However, according to the configuration of the roasting system 1 described above, excellent temperature control with high responsiveness is possible even when using an electric heater.

Explanation of Signs

[0096] 1 Roasting system 2 Pellet burner 2A Furnace body 3 Roaster 4 First passage 5 Second passage 6 Opening / closing damper 7 Third passage 8 Exhaust fan 9 Cyclone 10 Smoke elimination equipment 11 Passage 11a on-off damper 12 on-off damper 13 exhaust fan 14 passageway 15A, 15B on-off dampers 16 hot air introduction section 17 auxiliary air introduction means 18 gas burner (auxiliary hot air generation means) 20 rotating cylinder 21 exhaust bypass damper 22 passageway 23 exhaust damper 24 front cover 25 hopper section 26 raw material hopper damper 27 water supply means

Claims

1. A roasting system for roasting food materials such as coffee beans and nuts, a roaster for roasting the food materials, hot air generating means for generating hot air to be supplied to the roaster, a first passage for supplying hot air from the furnace body of the hot air generating means to the roaster, a second passage having one end connected to the first passage or the hot air generating means and the other end open to the outside, a first switch provided in the first passage, a second switch provided in the second passage, and comprising: the hot air generating means generates hot air by burning solid biofuel in the furnace body, characterized in that the first switch and the second switch are controlled to open and close according to the temperature difference from the target temperature of the roaster, and the temperature of the hot air supplied to the roaster is adjusted. Roasting system.

2. The first passage is provided with auxiliary air introducing means for introducing outside air into the first passage, and the amount of outside air introduced by the auxiliary air introducing means is controlled according to the temperature difference from the target temperature of the roaster, and the temperature of the hot air supplied to the roaster is further adjusted. The roasting system according to claim 1.

3. An exhaust fan is provided in the second passage, a third passage for exhausting the hot air used for roasting to the outside of the roaster is connected to the roaster, and the third passage is connected to the second passage on the upstream side of the exhaust fan. The roasting system according to claim 2.

4. The other end of the second passage is open to the outside through a cyclone and a smoke elimination device. The roasting system according to claim 1.

5. The roaster is provided with auxiliary hot air generating means for generating hot air by gas combustion. The roasting system according to claim 1.

6. A heat exchanger is provided in the middle of the second passage or the third passage. The roasting system according to claim 1.

7. The solid biofuel is coffee pellets, or wood pellets, or a mixture of coffee pellets and wood pellets. The roasting system according to claim 7.

8. Instead of the hot air generating means generating hot air by burning solid biofuel in the furnace body, an electric furnace is used, the electric furnace is equipped with an electric heater, and generates hot air using the electric heater as a heat source. The roasting system according to any one of claims 1 to 6.

9. A roasting method for roasting food materials such as coffee beans and nuts, using a roasting system comprising a roaster for roasting food materials, hot air generating means for generating hot air within a furnace body, a first passage connected to the hot air generating means and the roaster, a second passage having one end connected to the first passage or the hot air generating means and the other end open to the outside, and an opening / closing device provided in the first passage and the second passage. A hot air generating step of generating hot air by burning solid biofuel within the furnace body. A hot air supply step of supplying the generated hot air to the roaster via the first passage. A roasting step of roasting coffee beans using hot air within the roaster, and comprising: Characterized in that the first and second opening / closing devices are controlled to open and close according to the temperature difference from the target temperature of the roaster, thereby adjusting the temperature of the hot air supplied to the roaster. Roasting method.

10. Prior to the hot air supply step, further comprising a warm air step of closing the first opening / closing device and opening the second opening / closing device, and discharging the hot air generated within the furnace body to the outside via the second passage. The roasting method according to claim 9.

11. Characterized in that the hot air generating means is not stopped from the start of hot air generation within the furnace body until the end of food material roasting, including the warm air step. The roasting method according to claim 9.

12. Characterized in that the inside of the furnace body is maintained at a negative pressure from the start of hot air generation within the furnace body until after the end of food material roasting, including the warm air step, until the hot air generating means is stopped. The roasting method according to claim 9.

13. The roasting system is provided with auxiliary air introducing means for introducing outside air into the first passage. In the hot air supply step, according to the temperature difference from the target temperature of the roaster, the amount of outside air introduced by the auxiliary air introducing means is controlled to further adjust the temperature of the hot air supplied to the roaster. The roasting method according to claim 9.

14. The roasting system is provided with an exhaust fan in the second passage, a third passage for exhausting the hot air used for roasting from the roaster to the outside of the roaster is connected, and the third passage is connected to the second passage on the upstream side of the exhaust fan. In the roasting step, the hot air used for roasting is exhausted to the outside from the roaster via the third passage and the second passage. The roasting method according to claim 9.

15. The other end of the second passage is open to the outside via a cyclone and a smoke elimination device. In the roasting process, the hot air used for roasting is exhausted to the outside from the roaster through the third passage, the second passage, the cyclone, and the smoke eliminator. The roasting method according to claim 14.

16. The roasting system is provided with auxiliary hot air generation means for generating hot air by gas combustion in the roaster. In the hot air supply process, according to the temperature difference from the target temperature of the roaster, the amount of hot air introduced by the auxiliary hot air generation means is controlled and supplied to the roaster to further adjust the temperature of the hot air. The roasting method according to claim 9.

17. The roasting system is provided with a heat exchanger in the middle of the second passage or the third passage. The heat energy of the exhaust gas flowing through the second passage or the third passage is recovered by the heat exchanger. The roasting method according to claim 15.

18. In the hot air generation process, the solid biofuel burned in the furnace body is coffee pellets, or wood pellets, or a mixture of coffee pellets and wood pellets. The roasting method according to claim 9.

19. The hot air generation means is an electric furnace equipped with an electric heater. The hot air generation process is a process of generating hot air using the electric heater as a heat source by the electric furnace instead of a process of burning biofuel in the furnace body to generate hot air. The roasting method according to any one of claims 9 to 18.

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