Methods of roasting coffee beans

Abstract

The present invention relates to a method for roasting coffee beans in a roasting system (10), the system comprising: - a roasting apparatus (2), and - a flue gas treatment unit (3) configured to treat flue gas generated by the roasting apparatus, the flue gas treatment unit including at least one electrostatic precipitator (222), wherein during each roasting operation performed in the roasting apparatus, the method comprises the following steps: - monitoring the voltage at an offline point and / or the voltage at an electrode during the roasting operation; - comparing the monitored voltage with a predetermined upper voltage threshold V1 and a predetermined lower voltage threshold V2; and - indicating a cleanliness requirement if, during a time period Δt of the roasting operation, the monitored voltage is lower than the predetermined upper voltage threshold V1 and higher than the predetermined lower voltage threshold V2.

Description

Technical Field

[0001] This invention relates to an apparatus for roasting coffee beans in a safe environment. Background Technology

[0002] Roasting coffee beans is a well-known process. The main steps involve heating the coffee beans to the desired roast level, then cooling or quenching the heated beans to stop roasting. During heating, smoke is released. This smoke contains all the safe and desirable components, especially the common aromas of roasted coffee, but also contains less desirable and unsafe volatile organic compounds (VOCs) such as pyridine, 2-furanolol, caffeine furfural, formaldehyde, acetaldehyde… and particulate matter (PM2.5). 2.5 PM 10 )……

[0003] When roasting is carried out in manufacturing facilities that produce large quantities of roasted coffee beans, all conditions are typically provided to capture unsafe components.

[0004] However, a recent trend is to utilize small roasters for small-batch roasting in shops, restaurants, and cafes where customers can enjoy coffee brewed from freshly roasted beans. These roasters not only offer the advantages of freshness and a dramatic effect, but also distribute the pleasant aroma of roasted coffee throughout the shop or cafe.

[0005] However, as mentioned above, it also emits harmful components. When a baking machine is used in enclosed environments (such as shops, cafes, or restaurants), the emission of some components can become harmful depending on the size of the room and the room's ventilation... For people who work in the room for several hours, inhaling the fumes from a baking machine can cause health problems.

[0006] Therefore, in such an environment, it is recommended to stop emitting fumes from the baking machine to avoid any health problems for people present in the store. Existing solutions include destroying contaminants, such as afterburners or catalytic afterburners capable of thermally oxidizing contaminants, or retaining contaminants within the equipment, such as mechanical filters (metal sieves or paper filters), activated carbon filters, or electrostatic settlers, or combinations thereof.

[0007] Electrostatic precipitators capture PM particles typically ranging in size from 1.0 μm to 10 μm. The advantages of electrostatic precipitators include low purchase and operating costs and the absence of noise or heat generation during use. Because electrostatic precipitators capture contaminants that remain attached to the charged compartments of the device, the equipment must be cleaned regularly.

[0008] Cleaning warnings can be set based on the maximum number of hours the roaster can be operated or the maximum amount of coffee beans roasted. However, this alarm is only an estimate and is not entirely accurate, and it may prompt the operator to clean the filter too late, resulting in insufficient filtration efficiency during the final roasting operation and compromising the safety of personnel around the roaster. Alternatively, the operator can ignore this alarm and continue roasting, as the roaster and filter system remains operational, albeit with reduced filtration efficiency.

[0009] Specifically, if cleaning operations are not performed on time, a problem unique to electrostatic precipitators is breakdown due to the presence of particles within the device. While these breakdowns may be brief, during the time they occur, the flue gas is not filtered, resulting in at least two undesirable effects:

[0010] - First, particulate matter may be emitted from the rooms of cafes, shops, or restaurants where people are present.

[0011] Secondly, some unfiltered particulate matter can clog other filters located downstream of the electrostatic precipitator, such as activated carbon filters. Therefore, VOCs are no longer filtered by these filters.

[0012] This increases health problems in public indoor spaces.

[0013] Finally, the electrostatic settling device may be damaged.

[0014] The risk of these breakdowns is particularly high when the electrostatic precipitator reaches its limit for collecting particles, especially when the operator ignores early cleaning alarms. Summary of the Invention

[0015] The purpose of this invention is to solve the problems mentioned above.

[0016] Specifically, the purpose of this invention is to solve the problem of notifying operators when it is absolutely necessary to clean the flue gas filter of the electrostatic precipitator, and to provide such information in an accurate manner.

[0017] It is advantageous to avoid electrical breakdown caused by increased scaling and to anticipate the timing of electrical breakdown.

[0018] In a first aspect of the invention, a method for roasting coffee beans in a roasting system is provided, the system comprising:

[0019] -Baking equipment, and

[0020] - A flue gas treatment unit configured to treat the flue gas generated by the baking equipment, the flue gas treatment unit including an electrostatic precipitator.

[0021] The electrostatic settler includes at least one compartment, and

[0022] The compartment includes an electrical disconnect electrode, a collecting electrode, and a repulsive electrode, and

[0023] The compartment is supplied with electricity to apply a high voltage to at least a portion of the electrical disconnect and the electrodes.

[0024] During each baking operation performed in the baking equipment, the method includes the following steps:

[0025] - Monitor the voltage at these electrical outlets and / or the voltage at these electrodes during the baking process.

[0026] - Compare the monitored voltage with at least one predetermined upper voltage threshold V1 and one predetermined lower voltage threshold V2, and

[0027] - If, during the baking operation's time period Δt, the monitored voltage is lower than the at least one predetermined upper voltage threshold V1, while simultaneously higher than the predetermined lower voltage threshold V2,

[0028] This will display the required cleaning status.

[0029] The method involves roasting coffee beans using a system comprising two devices: a first, a roasting apparatus in which coffee beans are heated for roasting; and a second, a flue gas treatment unit configured to treat the fumes generated within the first roasting apparatus during the roasting of the coffee beans.

[0030] These two devices can be sub-components of a single main system, or alternatively, they can be considered as separate modules that work together during the baking process.

[0031] Any type of roasting equipment can be used. In the roasting equipment, the coffee beans are heated and preferably mixed to ensure that the heating of the coffee beans is uniform.

[0032] The heating source can be a burner (meaning combustion) fed by natural gas, liquefied petroleum gas (LPG), or even wood. Alternatively, the heat source can be a resistor, ceramic heater, halogen source, infrared source, or microwave source.

[0033] Preferably, the heating source is electric, so that the air pollutants generated during roasting are those produced solely by the heating of the coffee beans themselves, rather than by the combustion of gases that occur when the heating source is a gas burner using natural gas, propane, liquefied petroleum gas (LPG), or even wood.

[0034] During the roasting process, coffee beans can be mixed mechanically using a fluidized bed of hot air or by using stirring blades or a rotating drum.

[0035] Preferably, the roasting equipment is a hot air fluidized bed chamber. In such a chamber, heated air is forced with sufficient force through a screen or perforated plate beneath the coffee beans to elevate them. As the beans tumble and circulate within this fluidized bed, heat is transferred to them.

[0036] Alternatively, the roasting equipment may be a chamber in which coffee beans are tumbled in a heated environment. The chamber may consist of a cylinder that rotates along a horizontal axis, or it may include stirring blades to tumble the coffee beans in a heated environment.

[0037] The baking equipment includes an outlet from which fumes generated during the baking operation can be discharged.

[0038] Generally speaking, the flue gas treatment unit of the system includes a flue gas inlet, which is configured to cooperate with the flue gas outlet of the baking equipment and collect flue gas through the flue gas inlet.

[0039] Flue gas treatment units process flue gas to reduce or eliminate harmful pollutants contained in the flue gas, especially particulate matter such as PM1 and PM2.5. 2.5 and PM 10 .

[0040] This flue gas treatment unit includes at least one electrostatic precipitator.

[0041] An electrostatic settler is a particle collection device that filters flue gas by removing particles from the flue gas stream using electrostatic charges.

[0042] An electrostatic precipitator comprises one or more compartments. Each compartment is identical and includes:

[0043] - Off-line or corona metal wires in the upstream ionization region, and

[0044] - Collecting and repelling electrodes in the downstream collection zone. Typically, the electrodes are formed as plates. An electric field is generated through the electrodes and perpendicular to the flue gas flow. This electric field is generated by applying different voltages to the pair of electrodes or by applying a voltage to one electrode and grounding the other. Multiple pairs of spaced-apart collecting and repelling plates can be associated, allowing flue gas to flow in the space between the collecting and repelling plates.

[0045] Typically, the ionization line is supplied with electricity to apply a high voltage V. Particles in the flue gas flowing through the ionization zone are ionized, becoming either positively or negatively charged.

[0046] Then, as the flue gas flows through the downstream metal plate, the collecting electrode becomes a collector of ionized particles: charged particles are attracted to the plate and move toward it, forming a layer that remains on the plate. Thus, the discharged flue gas is cleaned from the charged particles already collected on the collecting electrode.

[0047] Electrostatic settlers can be used to capture particles that are present in sizes between 1.0 μm and 10 μm.

[0048] If the electrostatic precipitator comprises multiple compartments positioned sequentially in the flue gas flow, the first compartment filters most of the flue gas particles, and the second compartment filters the flue gas processed by the first compartment to achieve improved separation.

[0049] When performing a baking operation in a baking device, the method includes the following steps:

[0050] - Monitor the voltage at these electrical outlets and / or the voltage at these electrodes during the baking process.

[0051] - Compare the monitored voltage with at least one predetermined upper voltage threshold V1 and one predetermined lower voltage threshold V2, and

[0052] - If, during the baking operation's time period Δt, the monitored voltage is lower than the at least one predetermined upper voltage threshold V1, while simultaneously higher than the predetermined lower voltage threshold V2,

[0053] This will display the required cleaning status.

[0054] It has been observed that during the baking operation, the voltage V monitored at the line or electrode changes, exhibiting a general pattern of decreasing from an initial voltage V0 (corresponding to the high voltage applied to the line or electrode), then reaching a minimum voltage V_low, and then rising back to the initial voltage V0 from said minimum value at the end of the baking operation. Starting with a recently cleaned electrostatic settler and performing multiple baking operations, it has been observed that the minimum voltage value V_low becomes increasingly lower with each baking operation. In fact, this minimum value is a measurable parameter that provides information about the level of particle collection on the collecting electrode.

[0055] An alarm will be displayed when a portion of the monitored voltage, and especially the lowest value, falls below the voltage threshold, to alert the operator that a cleaning operation is required.

[0056] Different upper voltage thresholds can be set, which provides operators with information about cleaning requirements, and in particular about the progressive nature of cleaning urgency.

[0057] This upper voltage threshold V1 can be predefined so that when a baking operation is performed and the monitored voltage is above the upper voltage threshold, the baking operation can be performed without any alarm. However, if the monitored voltage falls below the upper voltage threshold during a particular operation, this means that the risk of breakdown during a future baking operation is almost certain, and the future operation cannot be performed while achieving effective flue gas filtration. Therefore, this method detects when the electrostatic precipitator needs cleaning.

[0058] Cleaning status requirements can provide different types of information, from simple suggestions to clean before a certain number of operations occur, to emergency cleaning at the end of the current baking operation, depending on the setting of the predetermined upper limit voltage threshold V1 as shown below.

[0059] Typically, an upper voltage threshold V1 is set, taking into account the high voltage applied to the electrical line or electrodes, and further considering the experiments described below.

[0060] In a preferred embodiment, this upper limit threshold V1 represents more than 50% of the value of the high voltage V0 applied to the electrical outlet or electrode.

[0061] During the use of the electrostatic precipitator, the voltage often drops to very low values ​​due to the transient presence of particles establishing contact between the repulsive and collecting electrodes. The voltage drops to extremely low levels at this point before rising back to normal as the particles are carried away in the flue gas stream.

[0062] During a very short period of time, these very low voltage values ​​are not considered in the analysis of the dirty state of the compartment, and for this purpose, according to the method, the monitored voltage is also compared with a predetermined lower limit voltage threshold V2, and if the monitored voltage is lower than the predetermined lower limit voltage threshold V2, there is no need to display a cleaning status requirement.

[0063] This predetermined lower voltage threshold V2 can be set to eliminate false breakdowns, and during this phenomenon, the low value of the monitored voltage must be disregarded.

[0064] Typically, the lower limit voltage threshold V2 depends on the configuration of the electrostatic precipitator, especially the applied high voltage, and can be further determined experimentally.

[0065] Typically, this lower threshold is much lower than the high voltage applied to the electrical line and electrodes, as well as the upper voltage threshold V1. The V1 / V2 ratio is typically greater than 10.

[0066] In a preferred embodiment, the lower limit predetermined voltage threshold V0 may be less than 100V.

[0067] Specifically, for high voltages above 5kV applied to the electrical line or electrodes, the lower limit predetermined voltage threshold V0 can be below 100V.

[0068] Preferably, the cleaning status requirement is displayed if the following conditions are met:

[0069] - The monitored voltage is lower than the at least one predetermined upper voltage threshold V1, while being higher than the predetermined lower voltage threshold V2;

[0070] and

[0071] - The time period Δt is higher than the predetermined time threshold Δt1.

[0072] By providing a second condition regarding the length of the time period Δt, during which the monitored voltage is below a predetermined upper voltage threshold V1, regardless of instantaneous abnormally low voltage values ​​- even if they are above a predetermined lower voltage threshold V2 - and then no cleaning status requirement is displayed.

[0073] Typically, the time interval Δt1 is about a few seconds, for example, about 5 seconds.

[0074] In one implementation, the cleaning status requirement can be indicated if the monitored voltage is below the at least one predetermined upper limit voltage threshold V1 and above the predetermined lower limit voltage threshold during more than one time period Δt of the baking operation.

[0075] In one embodiment, the steps of monitoring the voltage and comparing the monitored voltage are performed only during a portion of the roasting operation, preferably during the last 20% of the roasting operation, or during a portion of the roasting operation when the coffee bean temperature is above 150°C.

[0076] As described above, it has been observed that during the roasting process, the voltage V at the electrode or the line of electrical connection changes, exhibiting a general pattern of decreasing from the initial voltage V0, reaching a minimum voltage Vlow, and then rising back to the initial voltage V0 at the end of the roasting process. The minimum voltage value is also observed to be reached during the final portion of the roasting process (as shown in the figure below). Therefore, monitoring and comparing the voltage during the final portion of the roasting process is sufficient to analyze cleanliness requirements. The final portion of the roasting process can also correspond to coffee bean temperatures above 150°C.

[0077] Typically, the flue gas treatment unit includes a high-voltage process control panel configured to control the electrostatic precipitator. Preferably, the monitored voltage can be read from the process control panel.

[0078] In a preferred embodiment, the electrostatic settler includes at least two compartments positioned sequentially along the flue gas flow emitted by the baking machine, and the method is applied at least to the first compartment along the flue gas flow, preferably to each compartment.

[0079] It has been observed that, in this preferred embodiment, the first compartment captures approximately 90% of the particulate matter in the flue gas, meaning that subsequent compartments capture 90% of the remaining 10% of the particulate matter. Therefore, applying this method to the first compartment is sufficient to detect the risk of scaling and breakdown in this compartment.

[0080] Preferably, the method is applied to each compartment, which means that the voltage is monitored in each compartment.

[0081] Preferably, the flue gas treatment unit includes at least one other filtration device besides an electrostatic precipitator. This other filtration device may include, in the following list: high-efficiency particulate filter, metal filter, activated carbon filter, paper filter, cotton, or cloth. Optionally, the flue gas treatment unit may include additional filtration devices such as a wet scrubber, catalytic converter, or afterburner.

[0082] The filter configured to capture VOCs is preferably an activated carbon filter or a charcoal filter.

[0083] Preferably, depending on the direction of the flue gas flow within the flue gas treatment unit, the flue gas filtration subunit successively includes at least one filter to remove particulate matter, followed by an electrostatic precipitator, and then an activated carbon filter. This sequence prevents the activated carbon filter from being clogged by particulate matter.

[0084] The flue gas is driven into the flue gas treatment unit and various filters by a flue gas actuator configured to circulate the flue gas from the inlet to the outlet of the flue gas treatment unit. At the outlet, since the flue gas and contaminants have been captured, the treated stream can be safely released into the atmosphere of the room.

[0085] A flue gas actuator is typically a fan that drives the flue gas to the outlet.

[0086] Preferably, the fan is positioned near the outlet of the flue gas treatment unit. Therefore, the fan is not contaminated by untreated flue gas and its maintenance is easier.

[0087] According to a preferred embodiment, the flue gas filtration subunit includes at least the following sequentially:

[0088] -Metal mesh, then

[0089] - Electrostatic settler, then

[0090] - Activated carbon filter based on the movement of flue gas flow within the flue gas treatment unit.

[0091] Preferably, in this embodiment, the activated carbon filter is physically positioned above the electrostatic precipitator. Therefore, the flue gas is introduced upwards through subsequent devices.

[0092] In one embodiment, the value of the predetermined upper limit voltage threshold V1 varies according to the number of baking operations performed since the last cleaning operation of the electrostatic settler, and preferably, the value decreases as the number of baking operations increases.

[0093] Because the compartments become increasingly contaminated with each baking cycle, counting the number of cycles since the last cleaning operation provides a high-level estimate of the scale buildup. Based on experiments, the maximum number of baking cycles required before the compartment needs cleaning can be estimated.

[0094] Based on the estimation, when the number of baking operations reaches the predetermined number of baking operations N1, N2, and N3 respectively, the value of the predetermined upper limit voltage threshold V1 can be gradually reduced, and the upper limit voltage threshold can be set to the values ​​V11, V12, and V13 respectively.

[0095] This value can be gradually reduced, and at each step, it can correspond to a percentage of the maximum predetermined upper limit voltage threshold.

[0096] In another embodiment, the system may include a meter configured to estimate the number of baking operations that can still be performed before the cleaning operation requiring the electrostatic settler, and the value of the predetermined upper limit voltage threshold V1 varies according to the estimated number of operations, preferably decreasing as the estimated number of baking operations decreases.

[0097] Such meters can be configured to estimate the fouling condition of the electrostatic settling chambers and the number of roasting operations that can still be performed before cleaning is required. This estimate may be based on the number of roasting operations performed and / or the type of roasting operations performed and / or the type of coffee beans roasted during the roasting operations performed.

[0098] Specifically, when the estimated number of baking operations that can still be performed reaches the corresponding predetermined number of baking operations N1, N2, and N3, the number can be gradually reduced, and the values ​​of the predetermined upper limit voltage thresholds can be set to values ​​V11, V12, and V13, respectively.

[0099] When the value of the predetermined upper limit voltage threshold V1 changes, preferably, the corresponding type of cleaning status requirement can be displayed based on the value of the predetermined upper limit voltage threshold V1.

[0100] Specifically, as the value of the predetermined upper limit voltage threshold V1 decreases, the cleaning status can evolve from a simple message or warning to an emergency cleaning request alarm.

[0101] In one embodiment, the system includes a sensor configured to measure particulate matter in the flue gas treated by the electrostatic precipitator, and the method includes the following steps:

[0102] - Measure the concentration of the particulate matter during the baking process.

[0103] - Compare the cleaning requirement status with the measured value.

[0104] The sensor enables confirmation that the cleaning requirement status displayed by the analysis based on the monitored voltage is correct.

[0105] In a second aspect, a system for roasting coffee beans is provided, the system comprising:

[0106] -Baking equipment, and

[0107] - A flue gas treatment unit configured to treat the flue gas generated by the baking equipment, the flue gas treatment unit including at least one electrostatic precipitator.

[0108] The electrostatic settler includes at least one compartment, and

[0109] The compartment includes an electrical disconnect electrode, a collecting electrode, and a repulsive electrode, and

[0110] The compartments are supplied with electricity to apply high voltage to at least a portion of the electrical wires and electrodes.

[0111] - A control system that is operable to control the baking process according to baking methods such as those described above.

[0112] Based on the integration of the baking equipment and the flue gas treatment unit, the control system can be shared between the two devices, and the steps of the method can be shared between the control units of at least these two devices.

[0113] In one implementation, the method can be executed by the control unit of the baking equipment and the control unit of the flue gas treatment unit, with the two control units communicating together. Specifically:

[0114] -The control unit of the flue gas treatment unit can perform the following steps:

[0115] • Monitor voltage V,

[0116] • Compare the monitored voltage V with the upper and lower voltage thresholds, and

[0117] • If necessary, transmit the cleaning requirement status to the baking equipment.

[0118] - The control unit of the baking equipment can implement steps that display the status of cleaning requirements.

[0119] In another implementation scheme,

[0120] -The control unit of the flue gas treatment unit can perform the following steps:

[0121] • Monitor voltage V, and

[0122] • The monitored voltage V value is transmitted to the baking equipment, and

[0123] -The control unit of the baking equipment can perform the following steps:

[0124] • Compare the monitored voltage V with the upper voltage threshold and the lower voltage threshold.

[0125] • Display the cleaning requirement status if necessary.

[0126] In another implementation, the control unit of the flue gas treatment unit can perform all steps after receiving information from the baking equipment that the baking step has begun.

[0127] Preferably, the baking equipment may include a display unit to display the cleaning requirement status.

[0128] Alternatively, the electrostatic settler may include a device for displaying the status of cleaning requirements, such as an illuminated button.

[0129] In another alternative, the control system can be configured to display the cleaning requirement status on a mobile device that communicates with the system.

[0130] In a third aspect, a computer program is provided, the computer program comprising instructions for causing the system described in the second aspect to perform the method described in the first aspect.

[0131] In one implementation, the computer program can be executed by the control unit of the baking equipment and the control unit of the flue gas treatment unit, with the two control units communicating together. Specifically:

[0132] -The control unit of the flue gas treatment unit can perform the following steps:

[0133] • Monitor voltage V,

[0134] • Compare the monitored voltage V with the upper and lower voltage thresholds, and

[0135] • If necessary, transmit the cleaning requirement status to the baking equipment.

[0136] - The control unit of the baking equipment can implement steps that display the status of cleaning requirements.

[0137] In another implementation scheme,

[0138] -The control unit of the flue gas treatment unit can perform the following steps:

[0139] • Monitor voltage V, and

[0140] • The monitored voltage V value is transmitted to the baking equipment, and

[0141] -The control unit of the baking equipment can perform the following steps:

[0142] • Compare the monitored voltage V with the upper and lower voltage thresholds, and

[0143] • Display the cleaning requirement status if necessary.

[0144] In another implementation, the control unit of the flue gas treatment unit can perform all steps after receiving information from the baking equipment that the baking step has begun.

[0145] In a fourth aspect, a computer-readable storage medium is provided having the aforementioned computer program according to the third aspect stored thereon.

[0146] The foregoing aspects of the invention can be combined in any suitable manner. Furthermore, various features herein can be combined with one or more of the foregoing aspects to provide combinations other than those specifically shown and described. Further objects and advantageous features of the invention will become apparent from the claims, detailed descriptions, and accompanying drawings. Attached Figure Description

[0147] Specific embodiments of the present invention will now be further described by way of example with reference to the following accompanying drawings.

[0148] - Figure 1 This is a view of a system according to the present invention, showing the path of flue gas through the system.

[0149] - Figure 2 It shows Figure 1 One of the compartments in the electrostatic precipitator section of the flue gas treatment unit.

[0150] - Figure 3 It shows that according to Figure 1 and Figure 2 A block diagram of the system's control system.

[0151] - Figure 4 and Figure 5 The evolution of voltage and emitted particles monitored during the baking operation is shown under two different scaling conditions on the collecting electrode.

[0152] - Figure 6 yes Figure 4 An enlarged view of a baking operation is shown. Detailed Implementation

[0153] Systems for baking

[0154] Figure 1 A schematic diagram of a system including roasting equipment 1 and flue gas treatment unit 2 is shown. Functionally, the roasting equipment can be operated to roast coffee beans, and the flue gas treatment unit can be operated to treat the flue gas generated by the roasting equipment during roasting.

[0155] Baking equipment

[0156] The roasting equipment 1 is operable to receive and roast coffee beans within the roasting chamber 12.

[0157] Preferably, the roasting apparatus 1 includes a roasting chamber 12 into which a flow of hot air is introduced to agitate and heat the coffee beans. The hot air flow is typically generated by an airflow driver and a heater. These devices are positioned below the roasting chamber and introduce the hot air flow through the bottom of the chamber. In the accompanying drawings, the bottom of the chamber is configured to allow air to pass through; specifically, it may be a perforated plate on which coffee beans can be placed and through which air can flow upwards.

[0158] The airflow actuator can be operated to generate an upward airflow in the direction of the bottom of the container. The generated airflow is configured to heat, stir, and lift the beans. Therefore, the coffee beans are heated evenly. Specifically, the airflow actuator can be a motor-powered fan. An air inlet can be located within the base of the housing to feed air into the housing, and the airflow actuator blows this air in the direction of chamber 12.

[0159] The heater can be operated to heat the airflow generated by the airflow driver. Preferably, the heater is a resistor positioned between the fan and the perforated plate, resulting in the airflow being heated before entering chamber 12 to heat and lift the coffee beans.

[0160] Heaters and / or fans can be operated to apply a roasting profile to coffee beans, which is defined as a temperature versus time profile.

[0161] Preferably, the baking equipment includes a user interface 13, which is capable of:

[0162] - Input information about roasting (especially the amount of beans introduced into the roasting chamber and the desired roasting level) and output information about the roasting process (status, temperature, time), and

[0163] - Preferably, the output of information concerning the flue gas treatment unit 2, particularly the output of information concerning the cleaning of the electrostatic precipitator 222.

[0164] The roasting of coffee beans generates smoke, which is driven to the top opening 121 of the roasting chamber by an airflow generated by an airflow driver. Figure 1 As shown by arrow S1 in the diagram.

[0165] Generally, the bran collector is in fluid communication with the top opening 121 of the chamber to receive the bran that gradually separates from the coffee beans during roasting and is blown into the bran collector due to its lighter density.

[0166] The remainder of the flue gas is discharged through the flue gas outlet 11 located at the top of the baking equipment.

[0167] Flue gas treatment unit

[0168] The flue gas treatment unit 2 can be operated to receive and treat the flue gas S1 emitted at the flue gas outlet 11 of the baking equipment.

[0169] First, the flue gas treatment unit 2 includes a flue gas collection device 21 suitable for collecting flue gas. The flue gas collection device 21 or collection device forms an internal void space or pipe that guides the flue gas from the outlet 11 of the baking equipment along the direction of the filter device of the flue gas filter subunit 22 (dashed lines S1, S2, S3).

[0170] The flue gas filtration subunit 22 includes components suitable for filtering small particulate matter, such as PM1 and PM2.5. 2.5 and PM 10 The electrostatic settling device 222 comprises two identical compartments 222a and 222b positioned one after another in the flue gas flow.

[0171] Figure 2 The main components of compartment 222a are shown. Compartment 222a is configured to be traversed by smoke and includes, sequentially according to the direction of smoke flow:

[0172] - Multiple electrical disconnections 2221, then

[0173] Multiple collecting electrodes 2222 and repelling electrodes 2223, typically in the form of parallel plates, are positioned alternately at a distance of a few millimeters. These plates are oriented to create channels for generating flue gas flow.

[0174] A high voltage level (in the case of 8kV) is applied to the electrical line 2221 to generate a corona discharge that charges the flue gas particles entering the compartment.

[0175] An electric field is generated by the collecting electrode and the repulsive electrode by applying a voltage difference between them (e.g., in this case, applying 4 kV to the collecting electrode and fitting the repulsive electrode to the ground).

[0176] When charged particles flow in a channel defined by alternating collecting and repelling electrodes, these charged particles are attracted to the collecting electrode 2222 by an electric field perpendicular to the flow direction.

[0177] The cleaning operation of the electrostatic settler 222 includes removing the compartments 222a and 222b of the electrostatic settler from the flue gas filter unit and washing them with water and optionally with detergent, such as in a dishwasher.

[0178] Additionally, in the specifically illustrated embodiment, the flue gas filtration subunit 22 may include:

[0179] - Suitable for filtering PM2.5 10 Devices 223 for handling large particles, such as metal mesh and associated diffusers, typically metal grids positioned in front of (i.e., upstream of) the mesh.

[0180] - Activated carbon filter 221 suitable for removing VOCs from flue gas.

[0181] Preferably, the device for removing particulate matter is positioned upstream of the activated carbon filter. This upstream position ensures that particulate matter does not contaminate the activated carbon filter.

[0182] Physically, the electrostatic precipitator is positioned below the activated carbon filter to prevent particles from falling from the electrostatic precipitator onto the activated carbon filter when the electrostatic precipitator is de-energized.

[0183] The flue gas filtration subunit 22 includes a flue gas driver 23, typically a fan, for drawing contaminated flue gas from the inlet 211 of the collection device to the outlet 25 of the flue gas filtration subunit 22 (where the flue gas is safely distributed into the ambient atmosphere) through the flue gas filtration subunit 22 (where the flue gas is treated).

[0184] Control system of baking equipment and flue gas treatment unit

[0185] refer to Figure 1 , Figure 2 and Figure 3 Now consider control system 3: control system 3 can be operated to control flue gas filter unit 2, and in particular the electrostatic precipitator 222 of flue gas treatment unit.

[0186] Depending on the level of integration between baking equipment 1 and flue gas filtration unit 2, the control system can be shared between the control units of these two devices:

[0187] -If the flue gas treatment unit 2 is part of the baking equipment 1, the control unit of the baking equipment is usually the main unit, while the control unit of the filter is the slave unit.

[0188] -If the baking equipment 1 and the flue gas treatment unit 2 form two different devices (each of which has its own independent control unit), these control units can be configured to communicate to implement the method.

[0189] Communication can also be established between the systems of these two devices and mobile devices, especially for displaying information.

[0190] Figure 3 It shows Figure 1 The control system of the flue gas filtration unit 2.

[0191] The control system 3 typically includes, at the second level of the flue gas filtration unit 2: a processing or control unit 30, a power source 33, a memory unit 31, and a voltage sensor 34 for the ionization electrode.

[0192] The control unit 30 is configured to output feedback to the user interface 13 of the baking equipment, specifically displaying the cleaning requirement status of the electrostatic precipitator. In an alternative configuration, some processing units 2 may include their own user interface to display this status, such as an illuminated button that can be lit according to the status.

[0193] The control unit 30 can also display information about the following to the user interface 13:

[0194] - Cleaning instructions, such as tutorials, historical data on cleaning operations, ...

[0195] - Reset the alarm status.

[0196] The hardware of the user interface may include any suitable device, such as one or more of the following: buttons (such as joystick buttons, knobs, or push buttons), joysticks, LEDs, graphic or character LDCs, touch-sensitive graphical screens, and / or screen edge buttons. The user interface 20 may be formed as a single unit or multiple discrete units.

[0197] When the device is equipped with the communication interface 32 as described below, a portion of the user interface can also be located on the mobile application. In this case, at least a portion of the input and output can be transmitted to the mobile device via the communication interface 32.

[0198] Control unit 30 typically includes memory, input, and output system components arranged as integrated circuits (typically microprocessors or microcontrollers). Control unit 30 may include other suitable integrated circuits, such as ASICs, programmable logic devices (such as PALs, CPLDs, FPGAs, PSoCs), system-on-a-chip (SoCs), and analog integrated circuits (such as controllers). For such devices, the aforementioned program code can be considered programming logic or may additionally include programming logic, where appropriate. Control unit 30 may also include one or more of the aforementioned integrated circuits. An example of the latter is that multiple integrated circuits are arranged in a modular manner to communicate with each other, for example, a slave integrated circuit for controlling the flue gas treatment unit 2 communicates with a master integrated circuit for controlling the baking equipment 10.

[0199] The power source 33 can be operated to supply electrical energy to the controlled components and control unit 30. The power source 33 may include various devices, such as batteries or units for receiving and regulating mains power.

[0200] The control unit 30 typically includes a memory unit 31 for storing instructions as program code and optionally data. For this purpose, the memory unit typically includes: non-volatile memory, such as EPROM, EEPROM, or flash memory, for storing program code and operating parameters as instructions, and volatile memory (RAM) for temporary data storage. The memory unit may include separate and / or integrated (e.g., on a semiconductor die) memory. For programmable logic devices, instructions may be stored as programming logic.

[0201] The instructions stored in memory unit 31 can be idealized to include a program for determining the degree of dirtiness of the flue gas treatment unit of the system, and in particular, a cleanliness requirement (no cleaning required, emergency cleaning at the end of the current baking operation, etc.).

[0202] The control unit 30 is configured to output the value of the voltage V at the electrical line 2221, as measured by the sensor 34. In a preferred embodiment, the voltage can be read directly from the high-voltage PCB of the electrostatic precipitator.

[0203] During the baking process, control system 3 can operate as follows:

[0204] - Monitor the voltage at the offline point and / or the voltage at the electrode during the baking process.

[0205] - Compare the monitored voltage with a predetermined upper voltage threshold V1 and a predetermined lower voltage threshold V2, and

[0206] - If, during the baking operation period Δt, the monitored voltage is lower than the predetermined upper voltage threshold V1 and higher than the predetermined lower voltage threshold V2, a cleaning status requirement is displayed.

[0207] Figure 4 The evolution of PM emissions and monitored voltage is shown during continuous baking operations (n°1 to 6).

[0208] Curve C shows the PM emitted during the baking operation and measured upstream of the electrostatic precipitator (i.e., before being treated by this filtration device). 2.5 The measured value.

[0209] During these baking operations, the voltage at the respective electrical line 2221 of the upstream compartment 222a and the downstream compartment 222b is represented by curves A and B, respectively.

[0210] During the baking operation, the voltage V at the electrical disconnect was observed to vary, exhibiting a general pattern of decreasing from an initial voltage V0 (approximately 7 kV), reaching a minimum voltage V_low (indicated by the black dot), and then rising back to the initial voltage V0 at the end of the baking operation. Starting with a recently cleaned electrostatic precipitator and performing multiple baking operations, the minimum voltage value V_low was observed to decrease with each baking operation, as shown by the dashed line. This minimum value is a measurable parameter that provides information about the particle collection level on the collecting electrode.

[0211] When a portion of the monitored voltage, such as the minimum value Vlow, becomes below the upper voltage threshold V1 (in... Figure 4 When the voltage is set and indicated at 4.5kV, an alarm will be displayed to draw the operator's attention to the fact that cleaning is required.

[0212] As can be seen from curve B, the monitored voltage in the other compartment 222b did not decrease considerably. This is due to the fact that the upstream compartment 222a traps approximately 90% of the PM. Therefore, the downstream compartment 222b will not scale up quickly.

[0213] The upper voltage threshold V1 can be predefined through a durability test during which a roasting operation emitting the highest level of PM (preferably roasting coffee beans to a dark level) is repeated, and the voltage is monitored. As the operation is repeated and the minimum voltage value decreases, the occurrence of the first breakdown indicates that a very high level of PM has deposited in the plate. Since these breakdowns are undesirable (PM is deposited in the room or clogs the downstream activated carbon filter, if present), the upper voltage threshold V1 is defined such that even if the voltage reaches this threshold during the roasting operation, no breakdown occurs during said operation.

[0214] Figure 5The evolution of PM emissions and monitored voltages during continuous baking operations denoted as n°x to n°x+5 is shown, where operation n°x+1 is the first operation, during which the monitored voltage is below a voltage threshold V1 set at 4.5 kV.

[0215] like Figure 4 As shown, curve C represents the PM2.5 emitted during the baking operation and measured upstream of the electrostatic precipitator. 2.5 The measured values, and during these baking operations, the voltages at the electrical line 2221 of the upstream compartment 222a and the downstream compartment 222b are respectively represented by curves A and B.

[0216] Curve A illustrates a situation where, between baking operation n°x and the two subsequent operations n°x+1 and n°x+2, the monitored voltage of compartment 222a becomes below V1 during each baking operation. During these two operations, no breakdown occurs, and the filtering operation remains safe. However, if further operations occur after baking operation n°x+2, note that during all subsequent baking operations n°x+3 to n°x+5, the monitored voltage drops very low to below V1, indicating that breakdown occurs systematically during these operations. Therefore, in a safe manner, the upper limit threshold V1 is set at a voltage higher than the first lowest voltage observed at the time of breakdown (3.2 kV during operation n°x+3).

[0217] Analysis of curve B reveals that during baking operations n°x+1 to n°x+3, the second downstream compartment still effectively captures PM; however, this second compartment also rapidly becomes fouled and undergoes breakdown without the ability to filter flue gas. Therefore, it is highly preferable to display an alarm urging the operator to clean the electrostatic precipitator immediately after baking operation n°x+1 ends and a problem is detected in the first upstream compartment.

[0218] Figure 6 It is taken from Figure 4 A magnified view of the baking operation at n°6. It is clear that at time t1, the monitored voltage drops to almost zero over a very short period. This value is below 100V, and the period is less than 5 seconds. This type of low voltage corresponds to a false breakdown. This is likely due to a brief contact established between the particles and the two electrodes, which disappears almost immediately as the particles are carried away by the flue gas flow. This false breakdown does not provide information about fouling in the compartments of the electrostatic precipitator. Therefore, if the monitored voltage is below the lower threshold V2, which itself is below the upper threshold V1, no cleaning status requirement is indicated. The lower voltage threshold V2 can be set to approximately 100V.

[0219] Use such as Figure 4 and Figure 5The baking operation experiment conducted by the electrostatic setter system and baking equipment shown allows for the pre-determination of the upper limit threshold value V1.

[0220] Furthermore, since the minimum voltages of curves A and B gradually decrease, multiple predetermined upper limit voltage thresholds V can be defined. 11 V 12 ..., where V 11 >V 12 >V1, such as Figure 4 The dashed lines in the diagram serve to gradually warn operators that different cleaning status requirements are becoming increasingly concerning. For example, when the monitored voltage remains above the upper limit threshold V... 11 When the monitored voltage is between the upper limit thresholds V12 and V11, a message can be displayed indicating that more than N1 baking operations can be performed before cleaning is required, where N1 corresponds to 2 / 3 of the total number of possible normal operations for the cleaned compartment. Then, when the monitored voltage is between the upper limit thresholds V12 and V11, a message can be displayed indicating that baking operations can be performed between N1 and N2 before cleaning is required, where N2 corresponds to 1 / 3 of the total number of possible normal operations for the cleaned compartment.

[0221] Then, when the monitored voltage is between the upper limit thresholds V1 and V12, a message can be displayed indicating that a baking operation of less than N2 can be performed before cleaning is required.

[0222] Finally, when the monitored voltage is below the upper limit threshold V1, a message is displayed indicating that cleaning must be performed before operating a new baking operation.

[0223] Typically, based on these predetermined experiments, an upper limit threshold V1 (or optionally a predetermined voltage threshold V1) is set in the baking system's settings menu. 11 V 12 ...). This threshold is stored in the memory 31 of the control unit 30. Based on this threshold, once the monitored value during a baking operation approaches this threshold, an alarm for cleaning is displayed.

[0224] Generally, when the voltage monitored during a baking operation reaches the upper limit threshold V1, the alarm urges the operator to clean the electrostatic precipitator before performing any new baking operation, because breakdown will occur systematically in the next baking operation, resulting in PM not being filtered.

[0225] This method is particularly useful when the operator forgets to clean the electrostatic settling tank, even though she / he has been notified via another cleaning alarm display, such as one based on the number of hours of baking operation. The new display, designed to urge the operator to perform emergency cleaning before the next baking operation, compels them to take action. This new display assures that if the operator follows the cleaning recommendations, the electrostatic settling tank will not break down in subsequent operations, and the public will remain in a safe environment around the baking system.

[0226] Preferably, during the baking process, the control system 3 is operable to display the cleaning status requirement if the following conditions are met:

[0227] - If, during the baking operation period Δt, the monitored voltage is lower than the at least one predetermined upper voltage threshold V1 and higher than the predetermined lower voltage threshold V2, and

[0228] - This time period Δt is higher than a predetermined time threshold Δt1. Preferably, this predetermined time threshold Δt1 is approximately 5 seconds.

[0229] exist Figure 5 During the baking operation n°x+1, it can be observed that during the time period Δt (which is longer than 1 minute), the monitored voltage in compartment 222a is below the threshold V1 (in fact, Figure 5 The time scale in the middle makes a baking operation within Figure 5 (Continued for at least 15 minutes). Such a low voltage over such a long period cannot be considered an isolated low voltage, and therefore this measured voltage is retained to trigger the cleaning alarm display.

[0230] If this time period Δt is very short, for example, less than 5 seconds, the voltage measured will not be retained to trigger the cleaning alarm display.

[0231] Taking into account the length of the time period Δt provides a more accurate indication of the cleaning requirements.

[0232] In alternative or supplementary methods, the control system may be operable to:

[0233] - Monitor the voltage at the offline point and / or the voltage at the electrode during the baking process.

[0234] - Calculate the moving average of the voltage monitored during the baking process.

[0235] - Compare the calculated moving average value with a predetermined lower voltage threshold V1, and

[0236] - If the moving average value is below the predetermined upper limit voltage threshold V1 during the baking operation period Δt, a cleaning status requirement is indicated.

[0237] Using a moving average to calculate voltage values ​​offers the advantage of smoothing out fluctuations and eliminating outliers across multiple measurement points, especially for false breakdowns or abnormally low voltage values ​​(below V1) occurring over a very short period of time.

[0238] Although the invention has been described with reference to the embodiments shown above, it should be understood that the invention protected by the claims is not limited in any way to the embodiments shown.

[0239] Various changes and modifications may be made without departing from the scope of the invention as defined in the claims. Furthermore, if known equivalents exist for a particular feature, such equivalents should be incorporated as expressly mentioned in this specification.

[0240] As used in this specification, the words “including,” “contains,” and similar terms should not be construed as having an exclusive or exhaustive meaning. In other words, these terms are intended to mean “including but not limited to.”

[0241] Index list in the attached figure :

[0242] Baking equipment 1

[0243] Flue gas outlet 11

[0244] Baking Room 12

[0245] Top Exit 121

[0246] User Interface 13

[0247] Flue gas treatment unit 2

[0248] Flue gas collection device 21

[0249] Flue gas filter subunit 22

[0250] Activated carbon filter 221

[0251] Electrostatic settler 222

[0252] Compartments 222a, 222b

[0253] Ionization electrode 2221

[0254] Collection board 2222

[0255] Repulsion plate 2223

[0256] PM filter 223

[0257] Smoke drive 23

[0258] Exports 25

[0259] Control System 3

[0260] Control Unit 30

[0261] Memory unit 31

[0262] 32 compartment current source

[0263] Power source 33

[0264] Ionization electrode voltage sensor 34

Claims

1. A method for roasting coffee beans in a roasting system (10), said system comprising: -Baking equipment (1), and - A flue gas treatment unit (2), configured to treat the flue gas generated by the baking equipment, the flue gas treatment unit including at least one electrostatic precipitator (222). • The electrostatic settler includes at least one compartment (222a, 222b), and • The compartment includes an electrical disconnect electrode (2221), a collecting electrode (2222), and a repulsive electrode (2223), and • The compartment is supplied with electricity to apply a high voltage to at least a portion of the collecting electrode and the repelling electrode, as well as to the electrical disconnect. During each baking operation performed in the baking equipment, the method includes the following steps: - Monitor the voltage at the electrical disconnect and / or the voltage at the electrode during the baking process. - Compare the monitored voltage with a predetermined upper voltage threshold V1 and a predetermined lower voltage threshold V2, and - If, during the baking operation time period Δt, the monitored voltage is lower than the predetermined upper voltage threshold V1 and higher than the predetermined lower voltage threshold V2, a cleaning status requirement is displayed.

2. The method according to claim 1, wherein, The ratio V1 / V2 is greater than 10.

3. The method according to claim 1 or 2, wherein, The cleaning status requirement is displayed if the following conditions are met: - The monitored voltage is lower than the at least one predetermined upper voltage threshold V1, while being higher than the predetermined lower voltage threshold V2; and - The time period Δt is higher than the predetermined time threshold Δt1.

4. The method according to claim 3, wherein, The predetermined time threshold Δt1 is less than 10 seconds.

5. The method according to claim 1 or 2, wherein, If, during more than one time period Δt of the baking operation, the monitored voltage is lower than the at least one predetermined upper limit voltage threshold V1 while being higher than the predetermined lower limit voltage threshold, the cleaning status requirement is displayed.

6. The method according to claim 1 or 2, wherein, The steps of monitoring the voltage and comparing the monitored voltage are performed only during a portion of the baking operation.

7. The method according to claim 1 or 2, wherein, The flue gas treatment unit includes a high-voltage process control panel configured to control the electrostatic precipitator, wherein the monitored voltage is read from the process control panel.

8. The method according to claim 1 or 2, wherein, The electrostatic settler includes at least two compartments (222a, 222b) positioned sequentially along the flue gas flow emitted by the baking machine, and the method is applied at least to the first compartment (222a) along the flue gas flow.

9. The method according to claim 1, wherein, The value of the predetermined upper limit voltage threshold V1 varies based on the number of baking operations performed since the last cleaning operation of the electrostatic settler.

10. The method according to claim 1, wherein, The system includes a meter configured to determine the number of baking operations that can still be performed before the cleaning operation of the electrostatic settler is required, and the value of the predetermined upper limit voltage threshold V1 varies according to the determined number of operations.

11. The method according to claim 9 or 10, wherein, Based on the value of the predetermined upper limit voltage threshold V1, the corresponding type of cleaning status requirement can be displayed.

12. The method according to claim 1 or 2, wherein, The system includes a sensor configured to measure particulate matter in the flue gas treated by the electrostatic precipitator, and the method includes the following steps: - Measure the concentration of the particulate matter during the baking process. - Compare the stated cleaning requirement status with the measured concentration.

13. The method according to claim 6, wherein, The steps of monitoring the voltage and comparing the monitored voltage are performed during the last 20% of the roasting operation, or during the portion of the roasting operation when the coffee bean temperature is above 150°C.

14. The method according to claim 9, wherein, The value decreases as the number of baking operations increases.

15. The method according to claim 10, wherein, The value decreases as the number of baking operations decreases.

16. A system (10) for roasting coffee beans, the system comprising: -Baking equipment (1), and - A flue gas treatment unit (2), configured to treat the flue gas generated by the baking equipment, the flue gas treatment unit including at least one electrostatic precipitator (222). The electrostatic precipitator includes at least one compartment (222a, 222b), and The compartment includes an electrical disconnect electrode (2221), a collecting electrode (2222), and a repulsive electrode (2223), and The compartment is supplied with electricity to apply a high voltage to at least a portion of the collecting electrode and the repulsive electrode, as well as to the electrical disconnect. - A control system (3), the control system comprising a processing unit (30), a storage unit (31) and a voltage sensor (34) for an ionization electrode, the control system being capable of performing the method according to any one of claims 1 to 15 to control the baking process.

17. A computer program product comprising instructions for causing the system of claim 16 to perform the method of any one of claims 1 to 15.

18. The computer program product according to claim 17, wherein, The calculations and programs of the computer program product are executed by the control unit (30) of the baking equipment and the control unit of the flue gas treatment unit, and the two control units communicate together.

19. A computer-readable storage medium having a computer program product according to claim 17 stored thereon.

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