Roasting plant with electric heating device

Abstract

Roasting system for roasting goods such as coffee beans, cocoa beans, nuts or kernels, including • a roasting chamber with an inlet and an outlet for a roasting gas, • a circulating line that connects the inlet to the outlet and through which the roasting gas circulates, • a blower arranged in the recirculation line and designed to convey the roasting gas in the recirculation line, • an electric heating device designed to come into contact with the roasting gas in the circulating line via a surface and to transfer a heat flow to the roasting gas, wherein • an electrical power supply is connected to the electric heating device and is designed to supply the electric heating device with energy in such a way that the temperature of the surface of the electric heating device at least temporarily assumes a value required for thermal cleaning of the surface of residues of the roasted material.

Description

[0001] The invention relates to a roasting system for roasted goods such as coffee beans, cocoa beans, nuts or kernels.

[0002] Coffee beans are roasted using heated air at temperatures up to approximately 400°C. The heated air is called roasting gas. The roasting gas temperature either has a constant, predetermined value or follows a specific time profile. The time profile of the coffee bean temperature during the roasting process is called the roasting profile. The coffee beans are heated in a roasting chamber by convective heat transfer from the roasting gas to the coffee beans. Alternatively, the roasting chamber itself may be heated, and heat may be transferred to the coffee beans within it by conduction. To ensure even roasting, the coffee beans are moved during the process. The roasting process is terminated by rapidly cooling the coffee beans with cooling air or by spraying them with water, preferably in a separate cooling chamber. Rotational fluidized bed (RFB) roasters are used for roasting.These include "rotating fluidized bean bed" roasters, fluidized bed roasters, drum roasters, and paddle wheel roasters. Roasters are available in both industrial versions, especially for large-scale roasting operations, and smaller versions, particularly for retail stores. With standard roasting systems, and after appropriate modifications, which may include adjusting the roasting profile, other products such as kernels, nuts, or cocoa beans can also be roasted.

[0003] In a conventional roasting process, the temperature increase of the coffee beans inside the roaster is relatively steep at the beginning of the roasting, gradually weakens later, and can rise steeply at the end of the roasting under the influence of an exothermic reaction.

[0004] It is known that the operating parameters of the roasting chamber must be adjusted to the characteristics and quality of the coffee beans. In particular, the roasting temperature, its temperature profile over time, the roasting time, and the amount of air used influence the roasting result. With RFB roasting chambers, the variability of the roasting parameters is especially high.

[0005] Industrial roasters are operated in recirculating air mode to better utilize the heat energy supplied to the roasting gas.

[0006] In industrial roasting systems, a recirculating air line, also known as a closed-loop system, is usually connected to the roasting chamber and runs past a fan before finally returning to the roasting chamber. Such a closed-loop system has the advantage that the already heated roasting gas remains in the line, meaning that only small amounts of heat need to be added to compensate for heat losses. This significantly increases the efficiency of roasting systems with a closed-loop system compared to systems where the entire volume of roasting gas has to be reheated. The heat is usually transferred to the roasting gas using a gas-fired burner, which employs an open flame to heat the roasting gas.

[0007] During roasting in the roasting chamber, various residues from the coffee beans, including oils contained within the beans, transfer to the roasting gas. These residues are transported with the roasting gas through the recirculation lines to the burner and the blower. These components can become contaminated and their functionality impaired. For this reason, it is common practice to use cyclone separators to clean the roasting gas of particulate matter and thus ensure a long service life for the coffee roasting system. In this context, the ease of maintenance of the components used is crucial for the efficient, cost-effective, and reliable operation of the coffee roasting system.

[0008] In recent times, ensuring the environmentally friendly operation of a coffee roasting plant has become increasingly important. This requires and makes sense to reduce or eliminate the use of fossil fuels wherever possible and instead utilize sustainable energy sources to power the roasting plant. However, from this environmental perspective, the efficient operation of a coffee roasting plant remains crucial.

[0009] European patent EP 3 178 330 B1 discloses a method and apparatus for roasting coffee beans. The method is characterized in that the temperature of the coffee beans during roasting is controlled by at least temporarily exposing the coffee beans to roasting gas in combination with cooling gas, wherein the cooling gas is ambient air. The method allows for the creation of various roasting profiles. In particular, it enables roasting profiles with a particularly steep temperature rise at the beginning of the roasting process and a particularly weak or even no temperature rise at the end.

[0010] Brazilian patent document BR 8503002 A discloses a coffee roasting plant with a closed-loop system. This coffee roasting plant is characterized by the fact that various energy sources can be used to heat the roasting gas in the closed loop. Possible energy sources include fuel gas, charcoal, or electricity.

[0011] Based on the prior art described above, the present invention aims to provide an industrial coffee roasting plant that allows for effective and efficient operation with the most sustainable energy supply possible.

[0012] The problem is solved with a coffee roasting system according to independent claims 1, 10, 11, 19, 24, 28, 29 and 33. Advantageous embodiments are the subject of the dependent claims and the description.

[0013] A roasting system according to the invention for a roasting product such as coffee beans, cocoa beans, nuts or kernels according to claim 1 comprises • a roasting chamber with an inlet and an outlet for a roasting gas, • a circulating line that connects the inlet to the outlet and through which the roasting gas circulates, • a blower arranged in the recirculation line and designed to convey the roasting gas in the recirculation line, • an electric heating device designed to come into contact with the roasting gas in the circulating line via a surface and to transfer a heat flow to the roasting gas, wherein • the electric heating device has several electric heat sources which are designed to come into contact with the roasting gas in the circulating line at their surfaces and to transfer a heat flow to the roasting gas, • the electric heating device has a housing that defines a through-channel forming part of the circuit and has at least one opening extending from an outside of the housing to the through-channel, and • the electric heating device has several interchangeable inserts, each comprising a plate-shaped support, an electric heat source arranged on one side of the plate-shaped support, and an electrical connection device arranged on the opposite side of the plate-shaped support, wherein the inserts with the plate-shaped supports are held in a sealing configuration at the edge of the at least one opening, the heat sources engage in the passage channel, and the electrical connection devices are arranged outside the housing. • and an electrical power supply is provided, which is connected to the electrical connection devices of the inserts of the electric heating device.

[0014] The roasting system has a chamber into which the material to be roasted is placed. The chamber preferably has corresponding flaps for filling and emptying. During the roasting process, the coffee beans or other material to be roasted are located in the chamber, where they receive the necessary heat from the roasting gas entering through the inlet. The roasting chamber is designed to hold several kilograms up to several hundred kilograms of coffee at a time. Furthermore, it is designed so that the roasting process is completed within a few minutes.

[0015] Where reference is made below to coffee beans with regard to the properties and effects of the invention, the statements also apply accordingly to other roasted goods.

[0016] A recirculation line for the roasting gas is connected to the outlet of the roasting chamber and is also connected to the inlet of the roasting chamber. This recirculation line allows the roasting gas to circulate between the outlet and inlet of the roasting chamber.

[0017] According to one design, the recirculation line and / or the roasting chamber can include means for supplying fresh air to the roasting gas and for removing roasting gas. Supplying fresh air and removing roasting gas ensures constant gas composition in the roasting gas. Otherwise, the roasting process would lead to an enrichment of the roasting gas with gases such as carbon monoxide.

[0018] To initiate the circulation, the coffee system is equipped with a blower. The blower is integrated into the circulation line; that is, the circulation line includes the blower as a section. The blower can be, for example, a radial blower or have a different design. The type of blower depends, among other things, on the volume of roasting gas being conveyed.

[0019] Furthermore, an electric heating element is located in or on the circulating line. According to the invention, the heating element is electrically operated. The heating element absorbs electrical energy, converts it into a heat flow, and transfers this to the roasting gas circulating in the circulating line. The electric heating element can also be referred to as a heating coil or electric air heater.

[0020] According to the invention, a surface of the electric heating device comes into contact with the roasting gas in the circulating line. The surface is warmer than the roasting gas. Due to the temperature gradient between the surface and the roasting gas, the heating device transfers heat to the roasting gas. Consequently, the roasting gas has a higher temperature downstream of the heating device than upstream of it.

[0021] It is possible that the heating element is fully integrated into the circulating line and constitutes a separate section of it. However, it is also possible that only the aforementioned surface protrudes into the circulating line and transfers the heat energy to the roasting gas there.

[0022] Furthermore, an electrical power supply is available and connected to the heating system. This power supply provides energy to the electric heating system. This can be a connection to the electricity grid or a power generation system directly connected to the coffee roasting plant. In particular, power generation systems for sustainable electricity production, such as wind turbines or water turbines, dams, and photovoltaic systems, are suitable. However, other suitable electrical energy sources can also be used.

[0023] The fact that the coffee roasting system according to the invention has a recirculating system ensures that it can be operated efficiently. Only as much heat needs to be added to the roasting gas via the heating devices as is lost through heat losses via the recirculating systems and the roasting unit itself. As a rule, i.e., with good insulation, only a small amount of power is therefore required for the continuous heating of the roasting gas.

[0024] The electrically powered heating system ensures that the roasting plant can be supplied with energy from sustainable sources such as hydropower or wind power. The electric heating system can be designed without moving parts, making it particularly low-maintenance and durable. Due to its high energy efficiency, an electric heating system is inexpensive to operate, provided there is sufficient and affordable electricity available. Furthermore, the variable power output of an electric heating system allows for precise adjustment of the roasting profiles. Finally, an electric heating system requires no gas supply and does not operate with an open flame.This increases the operational safety of an electric heating system compared to a conventional, gas-fired heating system and prevents combustion products from contaminating the roasting material and / or being released into the environment. The electric heating system reduces or eliminates the consumption of natural gas, propane, or other fuels and, consequently, the emission of hydrocarbons, carbon monoxide (CO), and methane.

[0025] According to the invention, the heat flow transferred from the electric heating device to the roasting gas is transferred by means of several heat sources. These can also be referred to as heating elements. Each of the several heat sources individually transfers a heat flow to the roasting gas, so that the roasting gas experiences a total heat flow corresponding to the heat flows of the several heat sources. This total heat flow allows the roasting gas to be heated to a temperature sufficient to achieve a predetermined roast level of the coffee beans in the roasting chamber. Furthermore, the heat flows transferred by the heat sources can be configured to maintain a specific roasting profile, which is defined by a change in the temperature in the roasting chamber over time. Each of the heat sources is powered by electrical energy supplied by the electrical power supply.

[0026] The heat flow can be adjusted via the energy supply, with each heat source being supplied with the same power or with different power outputs. This allows all or only some of the heat sources to be operated simultaneously. The heat flow delivered by each heat source can also be adjusted by modifying the electrical power supplied to it. In this way, the heat flow delivered to the roasting gas can be controlled to achieve a specific roasting temperature or maintain a particular roasting profile. It is also possible to switch the individual heat sources on and off sequentially to avoid significant fluctuations in the network load. This allows, in particular, the peak current draw to be limited, thus preventing system overload.To enable the aforementioned operating modes, the power supply can be designed accordingly and electrically connected to the respective electrical connection devices of the inserts.

[0027] In addition to the heat sources, the electric heating device also has a housing. This housing defines a passageway that forms part of the circulating line. The housing, and thus the electric heating device, is integrated into the circulating line in this way, with a housing wall that defines the passageway also forming part of the circulating line, so that the housing itself constitutes part of the circulating line. The roasting gas circulating in the circulating line therefore also passes through the housing of the heating device.

[0028] The housing of the heating device has at least one opening extending from an outer surface of the housing to the passage channel. During operation, the outer surface does not come into contact with the roasting gas. This opening provides a connection between the environment on the outer surface of the housing and the passage channel on the other side.

[0029] The heating unit has several inserts, each comprising a plate-shaped support that is held in a sealing configuration at the edge of at least one opening. In this way, the inserts with the plate-shaped supports seal the housing, preventing roasting gas from escaping from the circulating line in the area of ​​the at least one opening.

[0030] If only one opening is provided for all inserts, the plate-shaped supports are arranged side by side so that they completely cover the opening. The plate-shaped supports seal against the edge of the opening and abut each other along their adjacent lateral edges, thus sealing the opening completely. If the opening is rectangular, the plate-shaped supports can also be rectangular and arranged parallel to each other, abutting each other laterally. If multiple openings are provided, preferably only one insert is used in each opening, with the plate-shaped support of each insert sealing against the perimeter of the opening.In another design with multiple openings, several inserts are placed in at least one of the openings, which, as in the design with only a single opening, seal the opening.

[0031] Between the edge of the plate-shaped supports and the edge of the at least one opening and, if applicable, the adjacent lateral edges of the plate-shaped supports, sealing elements may be present, which may be components of the inserts or the housing or separate components.

[0032] The plate-shaped supports are preferably detachable, preferably non-destructively detachable, held at the at least one opening, so that the inserts can be removed from the at least one opening and replaced by another, similar or differently designed insert. Replacing them with a differently designed insert makes it possible, for example, to make optimizations or adapt the roasting system to changed requirements. The inserts thus constitute separate modules.

[0033] The inserts comprise, in addition to the plate-shaped support, one of several heat sources and an electrical connection device. The respective heat source and the electrical connection device are arranged on opposite sides of the plate-shaped support, and both can be permanently attached to it. Accordingly, the electrical connection device, which could be, for example, an electrical connector, is located on the outside of the housing, which does not come into contact with the roasting gas. The heat source, on the other hand, extends into the passage channel by virtue of how the respective insert is held in the at least one opening in the housing, and is therefore located within it. Since the insert is placed into the housing or the passage channel along with the heat source during assembly, it is referred to as an insert. If the heat source consists of one or more heating elements, the insert can be inserted deep into the housing or passage channel.The plate-shaped support can be attached to the housing using fasteners such as screws. Centering devices, such as centering pins, can ensure the desired alignment, allowing the desired sealing effect to be achieved. Alternatively, the plate-shaped support can be spot-welded or welded to the housing, and can be removed from the housing, for example, by grinding.

[0034] The inventive provision of several modular, interchangeable inserts, each with a heat source, makes it easy to transfer a heat flow to the roasting gas using purely electrically operated heat sources. This heat flow is sufficient to roast even large quantities of the aforementioned product on an industrial scale. Each heat source on the respective insert only needs to provide a portion of the power and therefore only needs to be designed accordingly. The inserts can be installed individually and attached to the housing with the plate-shaped support, thus simplifying assembly. The power-carrying components, such as cables, connections, or the heat sources themselves, can be dimensioned and designed accordingly, which simplifies the design and assembly process.

[0035] The use of interchangeable inserts also enables easy maintenance and cleaning of an electrically operated roasting system. An insert, along with its attached heat source, can be easily removed from the housing and replaced with another insert, allowing for easy maintenance and cleaning of the removed insert while the roasting system continues to operate. The removed insert is easily accessible for maintenance or cleaning, further simplifying these tasks.

[0036] Furthermore, inserts with heat sources of varying nominal power can be used. By employing different inserts, a specific, desired nominal power output can be achieved. With the same basic roasting system design, different configurations with varying power outputs can be realized. This also makes it possible to use different materials with different heating characteristics for the heat sources of the various inserts. By taking into account site-specific conditions such as ambient temperature, power availability, etc., this allows for an operating mode that ensures a desired roast level is achieved by selecting appropriate inserts.

[0037] According to one embodiment of the invention, at least one heating element projects from the plate-shaped support into the through-channel, the heating element preferably being oriented perpendicular to the plate-shaped support. The at least one heating element is, in particular, a metal rod that heats up when a voltage is applied to it, causing a relatively large current to flow, thus generating heat. The use of a heating element is easily implemented in assembly and design using standard components. To achieve high efficiency and simplify assembly, the at least one heating element is arranged on the plate-shaped support such that it is oriented perpendicular to the support. A relatively large heating element can be used. However, several heating elements can also be used, in which case each of the heating elements can be designed with a smaller cross-section, in particular to save material.

[0038] According to one embodiment, the at least one heating element is U-shaped, and the curved side of the at least one U-shaped heating element faces away from the plate-shaped support. The U-shaped design allows for easy assembly, with the open ends of the "U" being attached to the plate-shaped support. The appropriate voltage can then be applied between these ends to heat the heating element.

[0039] According to one embodiment, the at least one insert has a plate-shaped support for the at least one heating element. This support is connected to the heating element, is arranged at a distance from the plate-shaped support, and rests against the wall of the passageway. The support supports the heating element, which, when heated, has a significantly reduced bending stiffness and could deflect under its own weight without the support. The support, which in turn rests against the wall of the passageway, thus ensures that the heating element retains its shape during operation and is therefore less susceptible to fatigue stress. Preferably, the support is designed as a plate with recesses for the heating element.

[0040] According to one embodiment, a transport element is attached to the plate-shaped support. This transport element is located on the outside of the housing and is designed to be lifted by a lifting device, preferably including a crane eye. The transport element allows an insert to be easily removed from and reinserted into the housing using a suitable device such as an overhead crane. Preferably, the insert is designed as a slide-in unit that can be installed and removed along a linear path, which particularly facilitates installation and removal using a crane.

[0041] According to one embodiment, the plate-shaped support has a form that is congruent with at least part of the opening. This avoids or minimizes a gap between the plate-shaped support and the at least one opening, thus simplifying or eliminating the need for additional sealing.

[0042] According to one embodiment, at least one plate-shaped support has fewer heating elements than at least one other plate-shaped support. Using different numbers of heating elements makes it possible to provide heat sources with varying nominal outputs. In particular, inserts with lower-output heat sources can be used to cover peak loads and remain switched off otherwise.

[0043] According to one embodiment, a temperature sensor is arranged on the housing next to at least one insert to measure the temperature of the roasting gas. The temperature sensor has a connection on the outside of the housing from which a temperature measurement signal can be tapped. By arranging the temperature sensors next to the surfaces of the heat sources, they are able to measure the temperature in the immediate vicinity of the heat sources. This allows for the early detection of impending overheating of the heat sources. For easy connection of the temperature sensor, e.g., to an evaluation unit, it has a connection on the outside of the housing. Preferably, the temperature sensor is designed as a rod-shaped component that protrudes through the housing.

[0044] In one design, the housing has several openings, and each insert is held in a sealing position at the edge of an opening by its plate-shaped support. The multiple openings allow for simple positioning and fixing of the inserts at the desired location within the housing.

[0045] According to other design variations, the housing includes at least one of the following features: • two end-end through-openings, preferably circular through-openings, forming an inlet and an outlet, each provided with a flange, wherein the remaining circuit line is connected to the flanges, • a tubular section with a rectangular cross-section that limits the passage channel, • the at least one opening, preferably at least one rectangular opening, preferably several parallel rectangular openings, in a side wall of the tubular section, • funnel-shaped sections with through openings at the ends facing away from each other and a connecting cross-section at the ends facing each other, which are connected to each other via a tubular section, preferably the tubular section with a rectangular cross-section, or directly, • insulation surrounding the housing, • an aluminum sheet covering the insulation.

[0046] According to these designs, the through-channel can be formed by a continuous cavity in the housing, connecting the inlet to the outlet and through which the roasting gas flows. The remaining circuit line can be easily and gas-tightly attached to and disconnected from the housing by means of flanges. If the housing has a tubular shape with a rectangular cross-section, attaching the inserts to the housing is particularly easy. Especially with a rectangular base shape for the plate-like supports, simple attachment of the inserts is facilitated by providing a rectangular opening(s) for the inserts. Furthermore, to enable loss-free transfer between the housing and the pipe sections of the circuit line located upstream and downstream, the housing can have funnel-shaped sections in the area of ​​the through-openings.Furthermore, the insulation prevents heat loss.

[0047] According to one embodiment of the invention, the circulating line, the roasting chamber, the electric heating device, the blower, preferably the roasting gas-carrying or contacting parts thereof and optionally further parts of the roasting system are made of a metallic material, in particular a material suitable for food processing, in particular steel, preferably stainless steel.

[0048] A roasting system according to the invention for a roasting product such as coffee beans, cocoa beans, nuts or kernels according to claim 10 comprises • a roasting chamber with an inlet and an outlet for a roasting gas, • a circulating line that connects the inlet to the outlet and through which the roasting gas circulates, • a blower arranged in the recirculation line and designed to convey the roasting gas in the recirculation line, • an electric heating device designed to come into contact with the roasting gas in the circulating line via a surface and to transfer a heat flow to the roasting gas, wherein • an electrical power supply is connected to the electric heating device and is designed to supply the electric heating device with energy in such a way that the temperature of the surface of the electric heating device at least temporarily assumes a value required for thermal cleaning of the surface of residues of the roasted material.

[0049] This roasting system according to the invention has a multitude of features that correspond to the previously described roasting system, also according to the invention, with a heating device according to claim 1, which has several heat sources. The corresponding features relate to the roasting chamber, the circulation line, the blower, and the electric heating device, insofar as the latter is configured to have a surface in contact with the roasting gas in the circulation line and to transfer a heat flow to the roasting gas. The features of the coffee roasting system according to claim 1 can be combined with the features of the coffee roasting system according to claim 10 and / or its embodiments. A coffee roasting system according to the invention with thermal cleaning can therefore, in particular, additionally have a heating device that has several heat sources, a housing defining a passage channel, and several interchangeable inserts.

[0050] According to the invention, the power supply is designed such that the electric heating device can be supplied with energy in such a way that the temperature of the surface of the electric heating device, with which the roasting gas comes into contact and which heats the roasting gas, reaches a very high temperature, at least temporarily. These temperatures can be up to or more than 600 °C. These high temperatures are suitable for carrying out thermal cleaning of the surface. Thermal cleaning means that residues of the roasted material adhering to the surface are removed.

[0051] The electrical power supply and the electric heating system are designed so that the surface can temporarily or permanently reach the high temperatures required for thermal cleaning. The corresponding materials and components are designed accordingly. In particular, the electronic components of the power supply are designed to provide the necessary high current and voltage levels. Furthermore, the components associated with the surfaces are made of appropriate materials. The power supply also features electronic controls that ensure the provision of the current and voltage levels required for thermal cleaning. These and / or other measures known to those skilled in the art enable the roasting system to repeatedly perform thermal cleaning without reducing its service life.

[0052] Furthermore, the electrical power supply is designed to be controlled and to create different surface temperatures, and consequently also different temperatures of the roasting gas. In this way, roasting profiles can be developed that ensure a good coffee flavor.

[0053] In one design, the roasting system features a cyclone separator located upstream of the heating unit and the blower in the recirculation line. This ensures that residues are removed from the roasting gas as completely as possible. This reduces the energy required for thermal cleaning.

[0054] Thermal cleaning of the heat transfer surface has the advantage of extending the efficiency and service life of the electric heating element. Without such thermal cleaning, the residues typically present in the roasting gas would permanently accumulate on the surface. These residues include smaller particles such as fine coffee bean dust and oil that is released from the coffee beans during roasting and carried along in the roasting gas. If these residues accumulate permanently on the heat transfer surface, they increase the thermal resistance between the surface and the roasting gas. Consequently, the heat transfer efficiency would be reduced. Furthermore, the heat transfer surface could overheat. Thermal cleaning also removes residues that could lead to a chemical reaction on the surface, such as...which could lead to particularly strong adhesion and / or corrosion. The temperatures for thermal cleaning must be selected depending on the size and material of the heating elements or other components of the heating device to which the surface belongs, so that they have a sufficiently long service life.

[0055] While the use of high temperatures primarily serves thermal cleaning, as previously described, it also offers further advantages. Depending on the size of the system and the roasting profile used, it can be beneficial to use high temperatures to heat the roasting gas as quickly as possible. This allows for consideration of the different characteristics and qualities of different coffee batches while simultaneously thermally cleaning the surface.

[0056] Furthermore, it should be noted that the heating elements belonging to the surfaces of the heating system represent a portion of the energy stored in the circulating system and thus contribute to the thermal inertia of the system. Using high temperatures means that only small surface areas are needed for heat transfer. This results in correspondingly smaller heating elements being required, reducing the thermal inertia of the roasting system and making it easier to follow specific roasting profiles.

[0057] A roasting system according to the invention for a roasting product such as coffee beans, cocoa beans, nuts or kernels according to claim 11, comprises • a roasting chamber with an inlet and an outlet for a roasting gas, • a circulating line that connects the inlet to the outlet and through which the roasting gas circulates, • a blower arranged in the recirculation line and designed to convey the roasting gas in the recirculation line, • an electric heating device designed to come into contact with the roasting gas in the circulating line via a surface and to transfer a heat flow to the roasting gas, where • an electronic controller is present which is designed to output an electrical signal, • a control rule is stored on the controller, which serves to determine the nature of the electrical signal depending on a control deviation, • a measuring device for measuring at least one temperature is available, • the control deviation is calculated as a difference between the measured temperature and a target temperature specified in the control regulation or a time-varying target temperature profile, • the electric heating device is designed to adjust the magnitude of the heat flow it emits depending on the nature of the electrical signal and • the temperature measuring device measures the temperature of the electric heating device or the roasting gas at the surface of the electric heating device that comes into contact with the roasting gas for heat transfer.

[0058] This roasting system according to the invention has a multitude of features that correspond to the previously described roasting system, also according to the invention, with a heating device according to claim 1, which has several inserts, and a thermal cleaning system according to claim 10. The corresponding features relate to the roasting chamber, the circulation line, the blower, and the electric heating device, insofar as the latter is configured to have a surface in contact with the roasting gas in the circulation line and to transfer a heat flow to the roasting gas. The features of the coffee roasting system according to claim 1 and / or claim 10 can be combined with the features of the coffee roasting system according to claim 11 and / or its embodiments.A coffee roasting system according to the invention with an electronic controller can therefore, in particular, additionally include a thermal cleaning system and / or a heating device which has several heat sources, a housing that limits a through-channel and several interchangeable inserts.

[0059] The electronic controller of the roasting system serves to regulate the electric heating element. The controller can be implemented as a computer, a microcontroller, or an electrical circuit. The heating element itself is the control element that can be adjusted. The heating element is controlled by an electrical signal output by the electronic controller. This electrical signal can be a simple electric current, the strength of which is set by the controller. Alternatively, it is also possible to use typical systems for data transmission in automated systems, such as a bus system, where the electrical signal represents the transmitted data.

[0060] The electrical signal is defined by a control rule stored on the electronic controller. This control rule is stored as a program on the computer or microcontroller. If it is an electrical circuit, the control rule is implemented via corresponding electronic components and their wiring. The control rule defines the value of the electrical signal as a function of the control deviation. Typical controllers have a proportional actuator, an integrative actuator, and a differential actuator, which take into account both the time course of the control deviations and the deviations themselves. However, depending on the roasting profiles used and the quality requirements, it is also possible to use more or less complex control rules.

[0061] To determine the deviations from the control system, a temperature measurement is taken using a temperature measuring device. This device can be, for example, a thermocouple or a contact sensor. Therefore, both temperature sensors that come into contact with the roasting gas and non-contact temperature sensors can be used.

[0062] The control deviations result from a difference between the measured temperature and a target temperature. This target temperature is usually a time-defined temperature profile. Depending on this profile, the coffee beans or roasting material are heated faster or slower, ensuring the coffee achieves the desired flavor. The calculation of these deviations can be performed continuously in real time or at discrete intervals, depending on the electronic hardware used.

[0063] Depending on the electrical signal resulting from the control deviations, the electric heating device is activated so that it emits a corresponding heat flow. This means that as soon as a deviation from the desired setpoint temperature occurs, the power consumed by the heating device and the heat transferred from the heating device to the roasting gas are adjusted in order to bring the roasting gas temperature up to the setpoint temperature as quickly as possible.

[0064] According to the invention, the temperature measurement takes place at the heating device. Measurement from the inside and / or from the outside is possible. For an internal measurement, the temperature inside a component with surfaces is measured close to the surface. A contact temperature sensor is particularly suitable for this purpose. For an external measurement, a non-contact temperature sensor, such as an infrared thermometer, is appropriate.

[0065] According to the invention, it is also possible to measure the temperature of the roasting gas near the surface for heat transfer.

[0066] Furthermore, the controller offers additional advantages. It ensures that even complex roasting profiles are adhered to with exceptional reliability, thus contributing to the production of delicious coffee and enabling the system to operate with low energy consumption. This is particularly crucial with regard to the energy efficiency goals of a sustainable operation.

[0067] According to the invention, the temperature measured at the surface is fed back and used to control the power consumption of the electric heating element. To achieve a long service life, it is important that this temperature does not exceed the maximum permissible temperature for the materials used. By measuring and feeding back the temperature, overheating of the surface of the electric heating element used for heat transfer can be prevented.

[0068] A control system with surface temperature feedback is also advantageous when the circulation of the roasting gas is temporarily interrupted and the roasting gas no longer moves near the electric heating elements. In such a case, the heat absorbed by the electric heating element is dissipated only by natural convection and no longer by forced convection. Consequently, without appropriate control, the surfaces would heat up considerably. This can be prevented by the surface temperature feedback system according to the invention, by reducing the power consumption of the heating element.

[0069] Furthermore, a heating system with surface temperature feedback offers the advantage of achieving very high dynamic response times. The temporal variation in heat transfer between the surface and the roasting gas is continuously incorporated into the control system. If the heat transfer surface becomes contaminated, for example, due to residues in the roasting gas, its heat transfer properties may be altered. Measuring the temperature at the heat transfer surface and feeding it back to the system allows for a response to such a scenario by increasing the power input to compensate for the contamination. Other changes to the heat transfer surface, such as those caused by corrosion, can also be compensated for by temperature feedback.In conventional roasting plants operated with a gas-fired burner, the return of the temperature to the surface is not easily possible due to the high temperature in the combustion chamber and the turbulent flow conditions associated with combustion.

[0070] Furthermore, to maximize service life, it is advantageous to continuously adjust the power consumption to surface temperature changes for heat transfer, which occur as a result of altered environmental conditions, for example, when heat losses are reduced due to high ambient temperatures compared to normal operation. By feeding back the surface temperature for heat transfer, even complex roasting profiles can be reliably maintained during continuous operation of a roasting plant under varying conditions.

[0071] According to one embodiment of the invention, the roasting plant has • at least one additional measuring device for measuring at least one additional temperature on and • The control deviation is calculated as a difference between the measured subsequent temperature and a setpoint temperature specified in the control regulation or a time-varying setpoint temperature profile for the subsequent temperature. • wherein the additional measuring device measures the further temperature of the roasting gas in the inlet and / or in the outlet and / or in the roasting chamber.

[0072] The additional measuring device can be any temperature measuring device according to the above-mentioned configurations. The control deviations are also calculated using the additional temperature measured by this device, for which an additional setpoint temperature or an additional time-varying setpoint temperature profile is defined in the control instructions. The setpoint temperature profile is compared with the additional measured temperature to calculate the control deviations. The control deviations thus consist of several partial control deviations. These can be fed back to the electronic controller separately or as a vector.

[0073] The temperature is measured at the inlet and / or outlet of the roasting chamber and / or within the roasting chamber itself. This temperature measurement serves to record the temperature of the roasting gas immediately before, during, or after contact with the coffee.

[0074] Measuring and monitoring the temperature of the roasting gas immediately before, during, or after the roasting process is particularly advantageous for ensuring, via the controller, that the roasting temperature of the coffee beans and the corresponding roast level are precisely achieved. Measuring and monitoring this additional temperature allows for more precise adherence to the desired roasting profile and thus provides control that is particularly beneficial for the coffee's flavor.

[0075] Furthermore, measuring the temperature in the vicinity of the roasting chamber is advantageous because it allows for better adaptation to changing operating conditions. This temperature measurement reveals whether temperature losses have occurred on the way to the roasting chamber that need to be compensated for. These temperature losses can be particularly significant at lower ambient temperatures. In such cases, adjusting the heating power of the heating system by feeding back the roasting gas temperature measured in the area of ​​the roasting chamber can be beneficial.

[0076] According to another design, the control regulation is designed in such a way that, in the event of a cold start of the roasting plant, the power consumption of the heating device is continuously increased at a defined rate or in stages until the control deviation falls below a predetermined level.

[0077] A cold start refers to a state in which the heating element, as well as the rest of the coffee roasting system, is at a temperature significantly lower than the usual operating temperature, e.g., ambient temperature. The power consumption limit imposed during a cold start is continuously increased at a defined rate or in stages until the control deviation falls below a predetermined threshold. This means that as soon as the control deviation is sufficiently small, the power consumption is increased to the nominal value.

[0078] An advantage of such a control regulation is that the electrically operated heating device is not immediately run at full load. If full load operation were selected directly after switching on, an overload could occur, necessitating disconnection from the power source. It would also be possible for an overload protection device to trip, causing the coffee roasting system to shut down. By limiting the power consumption at the beginning and increasing it gradually during operation, such power interruptions can be prevented.

[0079] According to one design, a setpoint or setpoint profile of the control rule can be adjusted by an operator using a specially designed input device of the controller.

[0080] The roasting system features a specially designed input device for the controller. The operator can therefore manually adjust the setpoints. However, it is also possible for the control parameters to be automatically adjusted in the operator's favor if there is a change in environmental conditions or other altered conditions, such as a new batch of coffee.

[0081] A controller with adjustable setpoints or setpoint profiles offers the advantage of responding effectively to changing environmental parameters. For example, different coffee varieties can be roasted using different roasting profiles. It's also possible to select different setpoint temperatures for different seasons, as changes in ambient temperature can affect the roasting process. Furthermore, this allows for limiting energy consumption, particularly when sustainably produced energy is scarce. In such cases, a setpoint profile can be selected that, for instance, is sufficient for a lower roast level, thereby reducing the system's energy consumption.

[0082] According to one embodiment, the controller contains a further control rule for a cleaning mode, and the controller has an input device designed to temporarily activate the further control rule when actuated, so that thermal cleaning of the surface of residues of the roasted material takes place.

[0083] Among other things, a control rule for a cleaning mode is stored. Using a switch also located on the controller or the roasting system, an operator or an automated operator can change the currently used control rule, as explained above. A new control rule is then activated. In this way, a cleaning mode can be activated in which a thermal cleaning of the surface is performed for heat transfer. As explained previously, this thermal cleaning serves to remove residues of the roasted material from the surface for heat transfer.

[0084] The advantage of such a roasting system, which can be switched to a cleaning mode, is that the high power output required for thermal cleaning is not constantly necessary and / or can be used selectively. Contaminants can be specifically burned off by activating the cleaning mode. In this way, the cleaning mode reduces the energy consumption of the coffee roasting system.

[0085] Furthermore, a cleaning mode of the type described is also advantageous with regard to service life. Since the high temperatures of thermal cleaning are only used for a limited time, there is correspondingly less fatigue of the surface material responsible for heat transfer.

[0086] According to one embodiment, several heating devices are present and / or the electric heating device has several electric heat sources which are designed to come into contact with the roasting gas in the circulating line at their surfaces and to transfer a heat flow to the roasting gas, wherein • at least one heating device and / or at least one electric heat source serves for fine control and at least one heating device and / or at least one electric heat source serves to supply a basic heat flow, and • the control regulation is designed in such a way that, in the event of a control deviation, the heat flow emitted by the at least one heating device for fine control or the at least one electrical heat source for fine control is essentially changed.

[0087] According to this design, not just one, but several heat flows are transferred to the roasting gas. As previously explained, the heat input occurs through surfaces that come into contact with the roasting gas and, due to a higher temperature compared to the roasting gas, result in a heat flow.

[0088] At least one of the heating devices and / or at least one of the electric heat sources is intended for fine-tuning. This means that this heating device and / or electric heat source is primarily responsible for responding to control deviations. The remaining heating devices or electric heat sources serve to provide a base heat flow and, when the heating device or electric heat source intended for fine-tuning is present, only need to be adjusted if the control deviation becomes very large, e.g., during a cold start. In particular, it is possible that the at least one heating device or at least one electric heat source used for fine-tuning has a lower rated power than the remaining electric heating devices and / or electric heat sources intended for providing the base heat flow.

[0089] The control regulation is designed accordingly, which means that in the event of a deviation from the control, it ensures that the power input and output of the heating device and / or heat source are primarily changed for fine control before the heat flow provided by the heating devices and / or heat sources intended for basic heat supply is changed.

[0090] The advantage of using multiple heating devices and / or electrical heat sources, only some of which are designed for fine-tuning, lies in the high dynamics of the overall system. As described above, the heating device and / or heat source intended for fine-tuning can be smaller than the others, allowing its temperature to change more rapidly in response to altered power consumption. For relatively small control deviations, a lower heat flow is usually sufficient for correction.

[0091] Fine-tuning is therefore used to compensate for unforeseen fluctuations. The base load is provided by the remaining heating systems and / or heat sources, which can be optimized and made more efficient. Depending on the size of the roasting system, it is possible to preferentially utilize the heating system and / or heat source used for fine-tuning when running through the temperature profiles.

[0092] According to one design • the roasting system has a measuring device for measuring the volume flow of roasting gas flowing through the line and • The control deviation is calculated as a difference between the measured roasting gas volume flow and a target roasting gas volume flow specified in the control specification or a time-varying target roasting gas volume flow profile.

[0093] This can be a standard flow meter, which, for example, measures pressure loss across an orifice and converts this into a volumetric flow rate, but other common sensors are also suitable. The measuring device for measuring the volumetric flow rate of the roasting gas flowing through the line is typically installed in the recirculation line.

[0094] The measured roasting gas flow rate is compared with a target roasting gas flow rate specified in the control instructions or with an additional time-varying target roasting gas flow rate profile to determine the difference, which is then factored into the controller's control deviation. In this way, the measured roasting gas flow rate is also fed back into the controller and can be used to control the electric heating element.

[0095] The advantage of feedback of the volumetric flow rate is that it provides the controller with even more parameters regarding the operating state of the roasting system. Taking these additional parameters into account, it can perform improved control. This improved control makes it possible, in particular, to adjust the temperature more quickly and precisely, both in the roasting chamber and at the surface used for heat transfer. This is because a change in volumetric flow rate necessitates a change in the heat input to maintain the same temperatures. This also prevents high peak temperatures. Therefore, consistent temperature control with feedback of the measured volumetric flow rate of the roasting gas is beneficial for both the dynamics of the roasting system and its service life.

[0096] According to one design • The blower is designed to adjust the size of the roasting gas volume flow delivered by the blower depending on the nature of the electrical signal, and / or • A throttle is present in the line, which is designed to adjust the size of the roasting gas volume flow delivered by the blower depending on the nature of the electrical signal.

[0097] This means that the roasting gas flow rate is not constant in the system, but can be adjusted. It is therefore possible to change the roasting gas flow rate using two control variables: the blower and the throttle. In this way, the roasting gas flow rate becomes an additional controlled variable, and the blower and / or throttle become another component of the control system. Adjustment via the blower is more efficient because it results in lower flow losses. However, using a throttle can be particularly advantageous in terms of dynamics, as it can be closed very quickly.

[0098] This design is particularly advantageous when combined with a volumetric flow rate measurement as described above. However, even without such a combination, adjusting the volumetric flow rate within the control loop can be useful, for example, to account for the changing density of the roasting gas due to temperature fluctuations. This allows for more precise control of the roasting gas temperature changes.

[0099] A roasting system according to the invention for a roasting product such as coffee beans, cocoa beans, nuts or kernels according to claim 19 comprises • a roasting chamber with an inlet and an outlet for a roasting gas, • a circulating line that connects the inlet to the outlet and through which the roasting gas circulates, • a blower arranged in the recirculation line and designed to convey the roasting gas in the recirculation line, • an electric heating device designed to have a surface in contact with the roasting gas in the circulating line and to transfer a heat flow to the roasting gas and • a bypass line that is connected at one end between the blower and the inlet to the circulation line and at the other end between the outlet and the blower to the circulation line.

[0100] This roasting system according to the invention has a multitude of features that correspond to the previously described roasting systems also according to the invention, comprising a heating device according to claim 1, which has several heat sources, a thermal cleaning system according to claim 10, and an electronic controller according to claim 11. The corresponding features relate to the roasting chamber, the circulation line, the blower, and the electric heating device, insofar as the latter is configured to have a surface in contact with the roasting gas in the circulation line and to transfer a heat flow to the roasting gas. The features of the coffee roasting systems of claim 1 and / or claim 10 and / or claim 11, as well as their embodiments, can be combined with the features of the coffee roasting system of claim 19 and / or its embodiments.A coffee roasting system according to the invention with a bypass can therefore in particular additionally include an electronic controller, a thermal cleaning system and / or a heating device which has several heat sources, a housing limiting a through-channel and several interchangeable inserts.

[0101] A bypass line is a cross-connection between individual sections of the recirculation line. In this case, the bypass line branches off from the recirculation line between the blower and the inlet of the recirculation line into the roasting chamber, i.e., relatively soon after the blower. The bypass line then branches off again into the recirculation line after the outlet from the roasting chamber, but before the blower.

[0102] The bypass line serves to divert the volume flow around the roasting chamber.

[0103] A bypass, when used with an electric heating element, offers the advantage of pre-heating the roasting gas before it enters the heating element or its effective area. This results in a smaller temperature difference between the heat transfer surface and the roasting gas. This reduced temperature difference can extend the service life of the heat transfer surface of the electric heating element.

[0104] When the gas flows through the bypass, no additional residues are added to the roasting gas, unlike in the roasting chamber. This reduces the amount of residue in the roasting gas, thus protecting the blower and heating system. It should also be noted that some of the residues are thermally destroyed in the heating system, so recirculating a portion of the flow through the bypass reduces the overall amount of residue in the gas flow. This has a positive effect on the service life and efficiency of the heating system.

[0105] Especially with an electrically operated heating system, a bypass is of great importance because it ensures that even when the coffee is changed and the flow through the roasting chamber is correspondingly restricted, circulation still takes place in the recirculation line during such roasting breaks. This allows the slow-reacting electric heating system to continue transferring heat stored in the components that form part of the heat transfer surface to a circulating flow of roasting gas. In this way, the presence of the bypass prevents the electric heating system from overheating.

[0106] The bypass can also be used during roasting breaks to thermally clean the system. With a largely unchanged energy input, the roasting gas routed through the bypass is heated sufficiently to thermally clean the surface of the electric heating element that comes into contact with the roasting gas. At the same time, the component is not damaged because the roasting gas continues to circulate through the bypass.

[0107] According to one design, the roasting plant has a fresh air supply which is connected to the circulating line in the direction of flow upstream of the point where the bypass line is connected to the circulating line.

[0108] The fresh air supply is connected upstream of the point where the bypass line connects to the recirculation line. This means that the fresh air supply begins before the branch into the bypass. Fresh air supply refers to an influx of air from outside the roasting system at the appropriate ambient temperature. Pre-heating or cooling of the incoming fresh air from outside is also possible. However, the fresh air has a lower temperature than the roasting gas and is free of residues from the coffee roasting process.

[0109] The advantage of a fresh air supply is that it makes it easier to follow a predetermined roasting profile. During the roasting process, the roasted coffee beans undergo an exothermic reaction, which causes the temperature of the roasting gas to rise. A fresh air supply at this point makes it possible to maintain a relatively constant roasting gas temperature, following the roasting profile.

[0110] In conjunction with an electric heating device, this property of a fresh air supply is particularly advantageous because, as explained previously, the electric heating device is slow to respond. Even after the power supply is switched off or reduced, the still-heated surface of the heating device continues to transfer heat to the roasting gas. To effectively cool the roasting gas, a fresh air supply before the roasting gas enters the roasting chamber is beneficial.

[0111] The advantage of positioning the fresh air intake before the bypass outlet is the resulting flexibility. Depending on the system's requirements and design, the fresh air can be directed through the bypass. This allows for particularly effective cooling of the electric heating element at appropriate times.

[0112] Furthermore, a fresh air supply is advantageous because it allows the composition of the roasting gas to be altered. The roasting process can lead to an accumulation of gases from the roasting process in the roasting gas, such as carbon monoxide. This accumulation can pose a safety risk or negatively affect the taste of the coffee. Supplying fresh air can prevent this accumulation.

[0113] According to one design, the roasting plant includes an exhaust gas line that is connected to the bypass line and / or to the circulation line between its connections with the bypass line.

[0114] The exhaust pipe is connected to the bypass pipe and / or to the recirculation pipe between its connections to the bypass pipe. A portion of the roasting gas flow is diverted to the environment via the exhaust pipe. With a fresh air supply, a corresponding amount of exhaust gas can be vented.

[0115] An advantage of an exhaust gas line and exhaust system is that it reduces the amount of residue in the roasting gas. Particularly in combination with a fresh air supply, the exhaust gas system also allows the gas composition of the roasting gas to be influenced in such a way that the gas composition remains as constant as possible despite the addition of gases from the roasting process. This prevents the negative consequences of the roasting gas becoming enriched with gases from the combustion process, as explained above.

[0116] Positioning the exhaust gas line on the bypass line and / or on the recirculation line between its connections with the bypass line ensures that the roasting gas flow is minimally affected upon entering the roasting chamber. This guarantees an uninterrupted roasting process, especially when using the RFB method.

[0117] According to one design, a thermal cleaning system is connected to the exhaust pipe, which cleans the roasting gas flowing through the exhaust pipe before it is released into the environment by heating it to at least 600°C.

[0118] The thermal cleaning system is preferably electrically operated, but can also be gas-powered. Its function is to briefly raise the roasting gas flowing through the exhaust pipes to a very high temperature of at least 600°C. This process burns off residues present in the roasting gas and cleans the gas before it is released into the environment. In this way, the roasting gas system meets the relevant environmental protection regulations.

[0119] According to one design • at least one bypass valve is present, which is designed to adjust the volume flow of the roasting gas diverted through the bypass line depending on the nature of an electrical signal, • and / or a fresh air damper designed to adjust the volume flow of roasting gas supplied by the fresh air supply depending on the nature of an electrical signal, • and / or an exhaust flap designed to adjust the volume flow of roasting gas discharged through the exhaust pipe depending on the nature of an electrical signal • and / or the system is designed for thermal cleaning, to be switched on and off depending on the nature of an electrical signal.

[0120] Valves are preferably arranged in the respective conduits or pipes and can be folded from an open to a closed position to close the conduit or pipe. In the closed position, the valve at least partially closes the conduit or pipe, preventing or severely restricting flow. In the open position, the valve releases the conduit or pipe, allowing at least a largely undisturbed flow to develop.

[0121] The dampers allow for the adjustment of partial flow rates through the bypass line, the fresh air supply, and the exhaust pipe. The corresponding dampers are positioned in the relevant pipe sections and are designed to adjust the respective flow rate based on an electrical signal. This means that when an external control signal is received, the respective dampers open or close to modify the flow rate. This ensures that the appropriate volume of roasting gas flows through the bypass, fresh air is added, and / or roasting gas is released into the environment via the exhaust pipe, depending on the operating conditions. The thermal cleaning system is also designed to be switched on or off based on an electrical signal.

[0122] In this way, the aforementioned components are able to be addressed and adjusted by a controller, regulator, or manual operating unit. A corresponding control signal can independently reach all the aforementioned valves or the thermal cleaning system, allowing the flow rates to be adjusted independently of one another.

[0123] The advantage of adjusting the corresponding volume flows is that it allows for a response to changes in operating conditions. In particular, it also makes it possible to follow more complex roasting profiles or corresponding target temperature curves. For example, at the beginning of a roasting profile, when the coffee beans are to be heated to a high temperature, it may be necessary to supply less fresh air, and conversely, at the end of the roasting profile, when there is also a large amount of residue in the roasting gas, a larger volume of fresh air may be required.

[0124] Furthermore, adjusting the flaps and the associated volume flow rates can be used to respond in a targeted manner to ambient conditions. This is particularly advantageous because, as previously explained, the electrically operated heating device according to the invention is slow to respond. This slowness can be counteracted by temperature control through the supply of cold fresh air.

[0125] A roasting system according to the invention for a roasting product such as coffee beans, cocoa beans, nuts or kernels according to claim 24 comprises • a roasting chamber with an inlet and an outlet for a roasting gas, • a circulating line that connects the inlet to the outlet and through which the roasting gas circulates, • a blower arranged in the recirculation line and designed to convey the roasting gas in the recirculation line, • an electric heating device designed to come into contact with the roasting gas in the circulating line via a surface and to transfer a heat flow to the roasting gas, where • the electric heating device has several electric heat sources which are designed to come into contact with the roasting gas in the circulating line at their surfaces and to transfer a heat flow to the roasting gas, wherein • an electrical power supply is connected to the electric heating device and is designed to supply the several electric heat sources with energy differently.

[0126] This roasting system according to the invention has a multitude of features that correspond to the previously described roasting systems also according to the invention, comprising a heating device according to claim 1, which has several inserts, a thermal cleaning system according to claim 10, an electronic controller according to claim 11, and a bypass according to claim 19. The corresponding features relate to the roasting chamber, the circulation line, the blower, and the electric heating device, insofar as the latter is configured to have a surface in contact with the roasting gas in the circulation line and to transfer a heat flow to the roasting gas. The features of the coffee roasting systems of claims 1, 10, 11, and / or 19 and / or their embodiments can be combined with the features of the coffee roasting system of claim 24 and / or its embodiments.A coffee roasting system according to the invention with several electrical heat sources can therefore in particular additionally include a bypass, an electronic controller, a thermal cleaning system and / or a heating device which has several heat sources, a housing limiting a through-channel and several interchangeable inserts.

[0127] The individual heat sources are designed as previously described for the electric heating element. This means they each have a surface that comes into contact with the roasting gas in the circulating line and, due to a temperature difference, transfers a corresponding heat flow to the roasting gas. Because the coffee roasting system has several electric heat sources with corresponding surfaces, multiple heat flows are transferred to the roasting gas. The various heat sources can be understood as individual modules of the electric heating element or as separate sub-heating units.

[0128] The electric heating system with its multiple electric heat sources is connected to a power supply. This power supply is designed so that each of the electric heat sources is supplied separately, and the energy output can be adjusted differently for each heat source. This allows the heat sources to deliver varying heat flows to the roasting gas. Additionally, the heat sources can have different rated power outputs and therefore different power consumptions.

[0129] An advantage of using multiple electric heat sources is that each one delivers a separate heat flow. Furthermore, according to the invention, it is also possible to individually adjust the respective heat flows. In this combination, the total heat flow delivered to the roasting gas can be adjusted with exceptional precision. This makes it possible to adhere to even complex roasting profiles with remarkable accuracy.

[0130] Using multiple electric heat sources also has the advantage that not all heat sources need to be fully utilized simultaneously. This increases the service life of the heat sources.

[0131] According to one embodiment, the heating device is designed so that the multiple electric heat sources can be removed and inserted separately. In this embodiment, the electric heat sources are therefore separate modules that can be individually removed from and reinserted into the heating device. This means that they each form separate units that can be individually removed from the heating device and individually supplied with energy. For this purpose, they are attached to the heating device with appropriate fasteners and connected to the heating device's power supply via appropriate power supply lines.

[0132] Structurally separating the heat sources is advantageous for enabling separate maintenance of each. Individual heat sources can be disconnected while the heating system continues to operate. This minimizes downtime due to maintenance work.

[0133] According to one embodiment, at least one electrical heat source has a lower rated power than the other electrical heat sources. In this embodiment, the heat sources have different rated powers, with the rated power of at least one heat source being lower than the rated powers of the remaining heat sources. The other equipment required to operate this heat source, such as cables or control cabinets, etc., is correspondingly smaller than that used for the other heat sources.

[0134] In particular, this has the advantage that the component connected to the surface for heat transfer can also be smaller. As a result, it stores less thermal energy present in the overall system, which contributes to the system's thermal inertia. This means that the low-power electrical heat source is less sluggish than the other heat sources and is therefore particularly well-suited for providing a variable heat flow. This highly dynamic variable heat flow also allows for precise adherence to complex roasting profiles and rapid responses to disturbances.

[0135] The advantage of using smaller power electronics and other components of a lower-powered heat source is that its energy consumption is correspondingly lower. This reduces the overall energy consumption of the roasting system. This is particularly relevant when system control or heat flow adjustment is required. In such cases, adjusting a high-powered heat source results in greater losses than adjusting a low-powered one.

[0136] In one embodiment, the electric heat sources are designed to adjust their emitted heat flow depending on the nature of an electrical signal. According to this embodiment, the heat flows emitted by the electric heating sources can be adjusted separately from the outside. This is achieved using an electrical signal. The electrical signal allows the emitted heat flow to be adjusted without requiring an operator to physically adjust the individual heat sources.

[0137] The advantage of adjusting the temperature using an electrical signal is that the heat sources can be controlled particularly well via a regulator. By regulating the heat sources, it is possible to adjust the total heat flow as quickly and precisely as possible. This allows a roasting profile to be followed even in the presence of disturbances, even under high dynamic conditions.

[0138] A roasting system according to the invention for a roasting product such as coffee beans, cocoa beans, nuts or kernels according to claim 28 comprises • a roasting chamber with an inlet and an outlet for a roasting gas, • a circulating line that connects the inlet to the outlet and through which the roasting gas circulates, • a blower arranged in the recirculation line and designed to convey the roasting gas in the recirculation line, • an electric heating device designed to come into contact with the roasting gas in the circulating line via a surface and to transfer a heat flow to the roasting gas, where • the roasting chamber is designed to fluidize the roasting material.

[0139] This roasting system according to the invention has a multitude of features that correspond to the previously described roasting systems also according to the invention, comprising a heating device according to claim 1, which has several inserts, a thermal cleaning system according to claim 10, an electronic controller according to claim 11, a bypass according to claim 19, and several heat sources according to claim 24. The corresponding features relate to the roasting chamber, the circulation line, the blower, and the electric heating device, insofar as the latter is configured to have a surface in contact with the roasting gas in the circulation line and to transfer a heat flow to the roasting gas. The features of the previously described coffee roasting systems of claims 1, 10, 11, 19, and / or 24, as well as their embodiments, can be combined with the features of the coffee roasting system according to claim 28 and / or its embodiments.A coffee roasting system according to the invention with a roasting chamber for fluidizing the roasting material can therefore in particular additionally have several electrical heat sources, a bypass, an electronic controller, a thermal cleaning system and / or a heating device which has several heat sources, a housing limiting a through-channel and several interchangeable inserts.

[0140] This coffee roasting system according to the invention comprises a combination of an electric heating device and a roasting chamber that utilizes the RFB (Reverse Flow Bed) method. According to the prior art, this method does not employ any moving parts to turn the coffee beans during the roasting process. Instead, an air bed is used to lift the coffee beans and thus turn them.

[0141] The RFB process is characterized by the absence of moving parts within the roasting chamber and the use of a relatively small amount of roasting gas. This results in very little thermally inert mass within the heated area of ​​the roasting system. This counteracts the thermal inertia caused by the electric heating element. Therefore, using the RFB process in combination with an electric heating element allows for a coffee roasting system that is more dynamic compared to one without the RFB process.

[0142] A roasting system according to the invention for a roasting product such as coffee beans, cocoa beans, kernels or nuts according to claim 29 comprises • a roasting chamber with an inlet and an outlet for a roasting gas, • a circulating line that connects the inlet to the outlet and through which the roasting gas circulates, • a blower arranged in the recirculation line and designed to convey the roasting gas in the recirculation line, • an electric heating device designed to have a surface in contact with the roasting gas in the circulating line and to transfer a heat flow to the roasting gas and • a gas-fired heating device designed to have a surface in contact with the roasting gas in the circulating line and to transfer a heat flow to the roasting gas.

[0143] This roasting system according to the invention has a multitude of features that correspond to the previously described roasting systems also according to the invention, comprising a heating device according to claim 1, which has multiple inserts, a thermal cleaning system according to claim 10, an electronic controller according to claim 11, a bypass according to claim 19, multiple heat sources according to claim 24, and an RFB roasting chamber according to claim 28. The corresponding features relate to the roasting chamber, the recirculation line, the blower, and the electric heating device, insofar as the latter is configured to have a surface in contact with the roasting gas in the recirculation line and to transfer a heat flow to the roasting gas. The features of the previously described coffee roasting systems of claims 1, 10, 11, 19, 24, and / or 28, as well as their embodiments, can be combined with the features of the coffee roasting system of claim 29 and / or its embodiments.A coffee roasting system according to the invention with a gas-fired heating device can therefore, in particular, additionally include a roasting chamber for fluidizing the roasting material, several electrical heat sources, a bypass, an electronic controller, a thermal cleaning system and / or a heating device that has several heat sources, a housing limiting a through-channel and several interchangeable inserts.

[0144] This roasting system has both an electric and a conventional heating element, also known as a burner. The gas-fired burner generates heat through a combustion process, which is then transferred to the roasting gas. Like the electric heating element, the burner can be integrated into the recirculation system.

[0145] According to the invention, the system is a hybrid. This hybrid system is characterized by having two separate heating devices, each with an electric and a conventional energy supply, which can independently deliver a heat flow to the roasting gas. The total heat flow delivered to the roasting gas is therefore composed of the partial heat flows delivered by either the electric or the gas-fired heating device.

[0146] A key advantage of a hybrid system is that even when electricity is unavailable or can only be purchased at a price that makes operating the system uneconomical, it can still continue to operate. The gas-fired heating system thus provides redundancy to the electric heating system and prevents extended downtime in the aforementioned situations.

[0147] Furthermore, hybrid operation is also advantageous with regard to the previously discussed residues that can accumulate on the surface for heat transfer. The open flame of the gas burner ensures that the roasting gas is heated sufficiently to burn off the residues from the roasting process. This results in fewer residues overall in the circulating system that could accumulate on the surface for heat transfer.

[0148] Furthermore, a key advantage of the hybrid system is that the various heat sources can be used for different purposes. The electric heating element is characterized by high efficiency and therefore results in low energy costs. On the other hand, as previously explained, it is slow to respond and therefore less suitable for following a roasting profile. The gas-fired heating element, especially if it is appropriately small, is capable of providing a rapidly changing heat flow. This is also due to the fact that it has no additional components in the circuit that would contribute to thermal inertia. The gas-fired heating element can thus achieve a similar effect to that of a previously described fine-tuning heating element or a heat source with a lower nominal output compared to the other heat sources.

[0149] According to one embodiment, the gas-fired heating device is designed to adjust the magnitude of its heat output based on the characteristics of an electrical signal. In this embodiment, the gas-fired component of the device is designed to be controlled externally. This control is achieved using an electrical signal. The electrical signal can be provided, in particular, by a controller or by an operator via a dedicated control unit.

[0150] The advantage of using an electrical signal to adjust the gas-fired heating system is that it allows for quick and easy changes. Furthermore, no modifications to the gas-fired heating system itself are necessary. This is particularly beneficial when using a control system. It allows for increased system responsiveness and precise adherence to a roasting profile.

[0151] According to one design, the gas-fired heating system can be operated with methane and / or natural gas and / or propane and / or hydrogen and / or e-fuels. As per the above list, any gaseous fuel can be used for the heating system. The burner can be operated with one of the listed gases. Alternatively, the burner can be a combination burner capable of operating with all of the listed gases. It is also possible that, with minor modifications, the gas-fired heating system can be adapted to operate with the respective gases.

[0152] Especially when combined with electric heating and high sustainability requirements, the use of hydrogen or e-fuels is advantageous. These can be produced using renewable energy and thus enable sustainable operation, even when a conventional gas-fired heating system is used to support the electric heating system. In particular, this allows for the creation of an environmentally friendly coffee roasting plant that still offers the previously described advantages of hybrid operation, especially with regard to high operational dynamism.

[0153] According to one embodiment, the gas-fired heating device is arranged upstream of the electric heating device.

[0154] An advantage of positioning the gas-fired heating unit upstream of the electric heating unit is that the residues from the roasting process are effectively burned before they reach the electric heating unit. This extends the service life, particularly of the electric heating unit, as explained above.

[0155] Furthermore, an advantage of this arrangement of the gas-fired heating device is that the roasting gas is already preheated before it enters the electrically operated heating device. This reduces the temperature difference between the surface of the electric heating device and the roasting gas, which has a positive effect on the service life of both the surface and the electric heating device.

[0156] A roasting system according to the invention for a roasting product such as coffee beans, cocoa beans, nuts or kernels according to claim 33 comprises • a roasting chamber with an inlet and an outlet for a roasting gas, • a circulating line that connects the inlet to the outlet and through which the roasting gas circulates, • a blower arranged in the recirculation line and designed to convey the roasting gas in the recirculation line, • an electric heating device designed to come into contact with the roasting gas in the circulating line via a surface and to transfer a heat flow to the roasting gas, where • Means for supplying fresh air are available, with which a volume flow of fresh air can be supplied to the roasting gas, • Means for roasting gas removal are available, with which a volume flow of roasting gas can be removed from the circulating line, • an electronic controller is present which is designed to output an electrical signal, • a control rule is stored on the controller, which serves to determine the nature of the electrical signal depending on a control deviation, • a measuring device for measuring at least a proportion of a gas in which roasting gas is present, • the control deviation is calculated as a difference between the at least one measured proportion of the gas and a target proportion specified in the control regulation or a time-varying target proportion profile, • the means for supplying fresh air are designed to adjust the size of the volume flow supplied by them depending on the nature of the electrical signal, and • the means for roasting gas removal are designed to adjust the size of the volume flow they remove depending on the nature of the electrical signal.

[0157] This roasting system according to the invention has a multitude of features that correspond to the previously described roasting systems also according to the invention, comprising a heating device according to claim 1, which has several inserts, a thermal cleaning system according to claim 10, an electronic controller for regulating the temperature of the surface for heat transfer according to claim 11, a bypass according to claim 19, several heat sources according to claim 24, an RFB roasting chamber according to claim 28, and a gas-fired heating device according to claim 29. The corresponding features relate to the roasting chamber, the recirculation line, the blower, and the electric heating device, insofar as the latter is configured to have a surface in contact with the roasting gas in the recirculation line and to transfer a heat flow to the roasting gas.The features of the coffee roasting systems described above in claims 1, 10, 11, 19, 24, 28 and / or 29 and / or their embodiments can be combined with the features of the coffee roasting system of claim 33 and / or its embodiments. A coffee roasting system according to the invention, with a control of at least one proportion of a gas in the roasting gas, can therefore, in particular, additionally comprise a gas-fired heating device, a roasting chamber for fluidizing the roasting material, several electrical heat sources, a bypass, an electronic controller for regulating the surface temperature for heat transfer, a thermal cleaning system, and / or a heating device comprising several heat sources, a housing defining a through-channel, and several interchangeable inserts.

[0158] This roasting plant of claim 33 differs from the roasting plant of claim 11 in that it includes a measuring device for measuring the at least one fraction of the gas in the roasting gas, the target fraction or target fraction profile, the means for supplying fresh air, and the means for removing the roasting gas. The remaining features, which do not differ, are identical, and the modes of operation and advantages described in claim 11 also apply.

[0159] This roasting system has means for fresh air supply and exhaust gas removal. These allow a volume flow of fresh air to be added to the roasting gas circulating in the recirculation line and roasting gas to be removed from the recirculation line. Specifically, the means for fresh air supply can be a fresh air duct connected to the environment. The means for roasting gas removal can be an exhaust gas duct through which the roasting gas can be released into the environment.

[0160] It is important to note that the gas composition of the roasting gas differs from that of the ambient air. The roasting process releases, among other things, carbon monoxide. Water vapor is also released into the roasting gas. Oxygen present in the roasting gas, however, is converted into oxygen. Changes in the gas composition of the roasting gas during the operation of a roasting system can negatively affect the taste of the coffee. In particular, an increase in the proportion of carbon monoxide can pose a safety risk.

[0161] The roasting system includes a measuring device capable of measuring at least one component of a gas in the roasting gas. This could be, for example, a sensor for measuring the proportion of water vapor, carbon monoxide, or oxygen in the roasting gas. The measured component is used to calculate the control error, which is then used by the control system to calculate the electrical signal.

[0162] Based on the control deviation and the resulting electrical signal, the fresh air supply system adjusts the incoming fresh air flow rate, and the roast gas exhaust system adjusts the outgoing roast gas flow rate. These systems incorporate devices such as dampers or fans to modify the flow rate. Adjusting these devices and the resulting change in flow rate alters the composition of the roast gas. For example, increasing both the incoming fresh air and the outgoing roast gas flow rates reduces the carbon monoxide and water vapor content of the roast gas. As previously described, dampers in the corresponding ducts can be opened to increase the respective flow rates.

[0163] The advantage of regulating the proportion of a specific gas in the roasting gas is that it allows for lower energy consumption in the roasting system. While a conventional, gas-fired roaster relies on a constant supply of fresh air through the fuel gas-air mixture, this is not the case with an electric heating element. In continuous operation, the proportion of gases originating from the roasting process would therefore continuously increase without a supply of fresh air and a corresponding exhaust of roasting gases. While this can negatively impact the coffee's flavor and pose a safety risk, the absence of a fresh air supply and exhaust system has the advantage of eliminating the need for additional energy to heat the fresh air.By regulating the minimum proportion of this gas in the roasting gas, it is ensured that only enough fresh air is supplied to keep the proportion of this gas at a sufficiently low level. This prevents negative consequences for taste and safety, while keeping energy consumption to a minimum.

[0164] In one embodiment, the electric heating element is arranged upstream of the blower. This allows some of the residues present in the roasting gas to be burned off in the heating element. The corresponding load on the blower is then low, thus extending its service life.

[0165] The advantages of those features of the roasting plant according to the invention of claim 1, which do not differ from the corresponding features of the roasting plants according to the invention of claims 10, 11, 19, 24, 28, 29 and 33, also apply to the roasting plants of claims 10, 11, 19, 24, 28, 29 and 33.

[0166] The invention will now be explained in more detail using an exemplary embodiment. The figures in the accompanying drawings illustrate the following: Fig. 1: a schematic diagram of a coffee roasting plant according to the invention; Fig. 2: a perspective view of an electric heating device; Fig. 3: A perspective view of a heat source of the electric heating device.

[0167] In Fig. Figure 1 shows a schematic representation of a coffee roasting system 1 according to the invention. The coffee roasting system 1 has a roasting chamber 2 with an inlet 3 and an outlet 4. The outlet 4 is connected to the inlet 3 via the circulation line 5. Roasting gas circulates in the circulation line 5 and through the roasting chamber 2, which serves to heat and roast the coffee in the roasting chamber 2.

[0168] A blower 6, an electric heating element 7, and a gas-fired heating element 8 are arranged in the circulation line 5. Before roasting gas from the roasting chamber 2 enters the gas-fired heating element 8 or the electric heating element, it passes through the roasting cyclone 9, where residues from the roasting process, such as coffee bean husks, are removed. This post-treatment of the roasting gas reduces the amount of residue from the roasting process that enters the gas-fired burner 8 and the electric heating element 7.

[0169] Furthermore, a bypass 10 is arranged downstream of the blower 6. The bypass 10 opens into the circuit line between the roasting chamber 2 and the gas-fired heating unit 8. The volume flow of the roasting gas through the bypass 10 depends on whether the damper 11 is closed and the damper 13 is open. As soon as the damper 11 is closed and the damper 13 is open, the roasting gas no longer flows into the roasting chamber 2 and instead flows through the bypass 10. The exhaust gas line 12 also branches off from the bypass 10. The dampers 13 and 14 control the volume flow that is discharged to the environment through the exhaust gas line 12. A line to the thermal cleaning system 15 branches off from the exhaust gas line 12. In addition to the exhaust gas line 12, the coffee roasting plant also has a purge air line 16, through which roasting gas can also be extracted.

[0170] Furthermore, the coffee roasting plant has a fresh air supply 19. The fresh air volume flow that enters the circulation line 5 is determined by the flap 20.

[0171] The roasting gas circulating in the circuit 5 is heated by heat flows from the gas-fired heating unit 8 and the electrically operated heating unit 7. The electric heating unit has several separate heat sources 21, each connected to an electrical power supply 22. The heat sources 21 can each be individually supplied with different electrical power by the electrical power supply 22. The different electrical powers supplied to the heat sources 21 ensure that the heat sources 21 deliver different heat flows to the roasting gas.

[0172] In addition, the gas-fired heating unit 8 transfers a further heat flow to the roasting gas via the flame 23. The flame 23 is generated with a mixture of fuel gas and air, with the air supplied via the combustion air line 24 and the fuel gas via the fuel gas line 25. This is therefore a hybrid system in which the entire heat flow is provided by both the electric heating unit 7 and the gas-fired heating unit 8. Depending on requirements, the individual heat sources 21 or the flame 23 can be varied to maintain a specific roasting profile. In particular, changing environmental conditions can be taken into account, and short-term adjustments to the heat quantity can also be made.

[0173] In addition to the roasting chamber 2, the heating unit 1 also has a cooling chamber 26, which is connected to a cooling air supply 27 that is a branch of the fresh air supply 19. After roasting, the coffee is transferred from the roasting chamber 2 to the cooling chamber 26. The coffee is cooled in the roasting chamber 26. The cooling air supply 27, with an additional fan 28, and the water supply 29 ensure a proper cooling profile. After cooling, the roasted and cooled coffee is transferred to the cooling hopper 30, from where the finished roasted coffee can be removed after a further cooling period. A cooling air / exhaust line 31 also leads from the cooling chamber 26. A cooling cyclone 32 is integrated into this line, in which the cool exhaust gas is cleaned of residues from the cooling process. The second cooling air / exhaust line 31 has a cross-connection to the exhaust line 12.

[0174] Fig. Figure 2 shows the electric heating device 7. In this perspective view, the individual heat sources 21 are particularly easy to see. It can be seen that a common housing 33 serves to suspend the individual heat sources 21. Furthermore, each of the heat sources has a separate power supply 34. In addition, corresponding temperature sensors 35 are connected to each heat source 21. The temperature sensors measure the corresponding temperature on the surfaces 36 of the heat sources.

[0175] The heat transfer surfaces 36 are realized via individual curved heating elements (heating rods). These are designed to be surrounded by roasting gas. The arrow labeled "Airflow direction" symbolizes the flow direction of the roasting gas. Due to their higher temperature compared to the roasting gas, they transfer a heat flow to the passing roasting gas. Each heat source 21 has a plurality of heating elements with corresponding heat transfer surfaces 36.

[0176] In one embodiment, the marked electrical heat source 21 has a power output of approximately 170 kW. With the exception of heat source 37, the remaining heat sources without reference numerals also have a power output of 170 kW. Heat source 37, however, has a lower power output of only 75 kW. This heat source 37 therefore also has less heating medium. As a result, it has lower thermal inertia and can reach different temperatures more quickly after a corresponding change in the power supply. Heat source 37 is therefore particularly well suited for fine control, where small disturbances must be compensated for in the short term to ensure that a predetermined roasting profile is maintained. The remaining heat sources 21 serve to provide a relatively constant power output to cover a base load. This results in a system power output of the heating device 7 of approximately 1 MW.This output is sufficient to roast large quantities of coffee in a short time.

[0177] Fig. Figure 3 shows a single heat source 21. From this view, it is easy to see that the individual heat sources can be removed separately and easily from the housing 27 (not shown in this view) and can also be easily reinserted into it. This makes maintenance of the heating devices 7 particularly easy.

[0178] Also included are a back panel 38 and a bracket 39. Fig. Figure 3 shows that each heating element is bent into a U-shape and connected to the rear wall 38 and, on the opposite side of the rear wall 38, also to the support 39. The support 39 is necessary because the heating elements heat up during operation and consequently lose rigidity. Without the support 39, they would not be able to reliably and permanently support their own weight. List of reference symbols 1 roasting plant 2 roasting chambers 3 Entrance 4 outlets 5. Circulation line 6 blowers 7 Electrically operated heating device 8 Gas-fired heating system 9 Roasting cyclone 10 Bypass 11. Flap for adjusting the bypass volume flow 12 Exhaust pipe 13. Flap for adjusting the exhaust gas volume flow 14. Flap for adjusting the exhaust gas volume flow 15 Thermal cleaning system 16 Purge air outlet 17. Flap for adjusting the volume flow of the thermal cleaning system 18 Valve for adjusting the flow rate of the thermal cleaning system 19 Fresh air duct 20 Valve for adjusting the fresh air volume flow 21 Electric heat source 22 Electrical power supply 23 Gas flame 24 Combustion air supply 25 Fuel gas supply 26 Cooling chamber 27 Additional fresh air supply 28 blowers 29 Water supply 30 cooling tanks 31 Cooling air / exhaust gas line 32 Cooling cyclone 33 cases 34 Energy supply 35 Temperature sensor 36 Surface area for heat transfer 37 Lower power electric heat source 38 Back panel 39 bracket QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 3 178 330 B1

[0009]

Claims

[1] Roasting plant (1) for roasting goods such as coffee beans, cocoa beans, nuts or kernels comprising • a roasting chamber (2) with an inlet (3) and an outlet (4) for a roasting gas, • a circulating line (5) that connects the inlet (3) with the outlet (4) and through which the roasting gas circulates, • a blower (6) arranged in the circulating line (5) and designed to convey the roasting gas in the circulating line (5), • an electric heating device (7) which is designed to come into contact with the roasting gas in the circulating line (5) with a surface (36) and to transfer a heat flow to the roasting gas, wherein • the electric heating device (7) has several electric heat sources (21) which are designed to come into contact with the roasting gas in the circulating line (5) at their surfaces (36) and to transfer a heat flow to the roasting gas, • the electric heating device (7) has a housing (33) that defines a through-channel forming part of the circuit line (5) and has at least one opening extending from an outside of the housing (33) to the through-channel, and • the electric heating device (7) has several interchangeable inserts, each comprising a plate-shaped support, an electric heat source (21) arranged on one side of the plate-shaped support and an electrical connection device arranged on the opposite side of the plate-shaped support, wherein the inserts with the plate-shaped supports are held in a sealing arrangement at the edge of the opening, the heat sources (21) engage in the passage channel and the electrical connection devices are arranged outside the housing (33), • and an electrical power supply (22) is provided which is connected to the electrical connection device of the inserts of the electric heating device (7). [2] Roasting system (1) according to claim 1, in which at least one heating rod protrudes from the plate-shaped support into the passage channel, wherein the heating rod is preferably oriented perpendicular to the plate-shaped support. [3] Roasting system (1) according to claim 2, wherein the at least one heating rod is U-shaped and the curved side of the at least one U-shaped heating rod is turned away from the plate-shaped support. [4] Roasting system (1) according to claim 2 or 3, wherein the at least one insert has a plate-shaped support (39) for the at least one heating rod, which is connected to the at least one heating rod, is arranged at a distance from the plate-shaped support and is supported on the wall of the passage channel. [5] Roasting plant (1) according to one of claims 1 to 4, in which a transport element is attached to the plate-shaped support, which is arranged on the outside of the housing (33) and is designed to be lifted by a lifting device, wherein the transport element preferably comprises a crane eye. [6] Roasting system (1) according to one of claims 1 to 5, wherein at least one plate-shaped support has a smaller number of heating rods than at least one other plate-shaped support. [7] Roasting system (1) according to one of claims 1 to 6, in which a temperature sensor (35) is arranged on the housing (33) next to at least one insert to measure a temperature of the roasting gas, wherein the temperature sensor (35) has a connection arranged on the outside of the housing from which a temperature measurement signal can be tapped. [8] Roasting system (1) according to one of claims 1 to 7, wherein the housing (33) has several openings and each insert with its plate-shaped support is held in a sealing arrangement at the edge of an opening. [9] Roasting system (1) according to any one of claims 1 to 8, wherein the housing (33) comprises at least one of the following features: • has two end-end through-openings, preferably circular through-openings, which form an inlet and an outlet and are each provided with a flange, wherein the remaining circuit line (5) is connected to the flanges, • a tubular section with a rectangular cross-section that limits the passage channel, • the at least one opening, preferably at least one rectangular opening, preferably several parallel rectangular openings, in a side wall of the tubular section, • funnel-shaped sections with through openings at the ends facing away from each other and a connecting cross-section at the ends facing each other, which are connected to each other via a tubular section, preferably the tubular section with a rectangular cross-section, or directly, • insulation surrounding the housing (33), • an aluminum sheet covering the insulation. [10] Roasting plant (1) for roasting goods such as coffee beans, cocoa beans, nuts or kernels comprising • a roasting chamber (2) with an inlet (3) and an outlet (4) for a roasting gas, • a circulating line (5) that connects the inlet (3) with the outlet (4) and through which the roasting gas circulates, • a blower (6) arranged in the circulating line (5) and designed to convey the roasting gas in the circulating line (5), • an electric heating device (7) which is designed to come into contact with the roasting gas in the circulating line (5) with a surface (36) and to transfer a heat flow to the roasting gas, wherein • an electrical power supply (22) is connected to the electrical heating device (7) and is designed to supply the electrical heating device (7) with energy in such a way that the temperature of the surface (36) of the electrical heating device (7) assumes at least temporarily a value required for thermal cleaning of the surface (36) of residues of the roasted material. [11] Roasting plant (1) for roasting goods such as coffee beans, cocoa beans, nuts or kernels comprising • a roasting chamber (2) with an inlet (3) and an outlet (4) for a roasting gas, • a circulating line (5) that connects the inlet (3) with the outlet (4) and through which the roasting gas circulates, • a blower (6) arranged in the circulating line (5) and designed to convey the roasting gas in the circulating line (5), • an electric heating device (7) which is designed to come into contact with the roasting gas in the circulating line (5) with a surface (36) and to transfer a heat flow to the roasting gas, wherein • an electronic controller is present which is designed to output an electrical signal, • a control rule is stored on the controller, which serves to determine the nature of the electrical signal depending on a control deviation, • a measuring instrument (35) for measuring at least one temperature is available, • the control deviation is calculated as a difference between the measured temperature and a target temperature specified in the control regulation or a time-varying target temperature profile, • the electric heating device (7) is designed to adjust the magnitude of the heat flow it emits depending on the nature of the electrical signal and • the temperature measuring device measures the temperature of the electric heating device (7) or of the roasting gas at the surface (36) of the electric heating device (7) that comes into contact with the roasting gas for heat transfer. [12] Roasting plant (1) according to claim 11, • which has at least one further measuring instrument (35) for measuring at least one further temperature and • the control deviation is calculated as a difference between the measured further temperature and a setpoint temperature specified in the control regulation or a time-varying setpoint temperature profile for the further temperature, • wherein the further measuring device measures the further temperature of the roasting gas in the inlet (3) and / or in the outlet (4) and / or in the roasting chamber (2). [13] Roasting plant (1) according to one of claims 11 to 12, wherein the control rule is designed such that, in the event of a cold start of the roasting plant (1), the power input of the heating device (7) is continuously increased at a defined rate or in stages until the control deviation falls below a predetermined level. [14] Roasting plant (1) according to one of claims 11 to 13, in which a setpoint or a setpoint profile of the control instruction can be adjusted by an operator by means of an input device of the controller designed for this purpose. [15] Roasting system (1) according to one of claims 11 to 14, in which a further control instruction for a cleaning mode is stored in the controller, and the controller has an input device which is designed to temporarily activate the further control instruction when actuated, so that a thermal cleaning of the surface (36) of residues of the roasted material takes place. [16] Roasting plant (1) according to one of claims 11 to 15, in which several heating devices (7) are provided and / or the electric heating device (7) has several electric heat sources (21) which are designed to come into contact with the roasting gas in the circulating line (5) at their surfaces (36) and to transfer a heat flow to the roasting gas, wherein • at least one heating device (7) and / or at least one electric heat source (37) serves for fine control and at least one heating device (7) and / or at least one electric heat source (21) serves to supply a basic heat flow, and • the control provision is designed in such a way that, in the event of a control deviation, the heat flow supplied by the at least one heating device (7) for fine control or the at least one electrical heat source (37) for fine control is substantially changed. [17] Roasting plant (1) according to any one of claims 11 to 16, • which has a measuring device for measuring the volume flow of roasted gas flowing through the line and • the control deviation is calculated as a difference between the measured roasting gas volume flow and a target roasting gas volume flow specified in the control specification or a time-varying target roasting gas volume flow profile. [18] Roasting plant (1) according to one of claims 11 to 17, wherein • the blower (6) is designed to adjust the size of the roasting gas volume flow delivered by the blower (6) depending on the nature of the electrical signal, and / or • a throttle is present in the line, which is designed to adjust the size of the roasting gas volume flow delivered by the blower (6) depending on the nature of the electrical signal. [19] Roasting plant (1) for roasting goods such as coffee beans, cocoa beans, nuts or kernels comprising • a roasting chamber (2) with an inlet (3) and an outlet (4) for a roasting gas, • a circulating line (5) that connects the inlet (3) with the outlet (4) and through which the roasting gas circulates, • a blower (6) arranged in the circulating line (5) and designed to convey the roasting gas in the circulating line (5), • an electric heating device (7) which is designed to come into contact with the roasting gas in the circulating line (5) with a surface (36) and to transfer a heat flow to the roasting gas and • a bypass line (10) which is connected at one end between the blower (6) and the inlet (3) to the circulation line (5) and at the other end between the outlet (4) and the blower (6) to the circulation line (5). [20] Roasting plant (1) according to the previous claim, comprising a fresh air supply which is connected to the circulating line (5) in the direction of flow upstream of the point where the bypass line (10) is connected to the circulating line (5). [21] Roasting plant (1) according to one of claims 19 to 20, comprising an exhaust gas line which is connected to the bypass line (10) and / or to the circulation line (5) between its connections with the bypass line (10). [22] Roasting plant (1) according to one of claims 19 to 21, in which a thermal cleaning system (15) is connected to the exhaust gas line, which cleans the roasting gas flowing through the exhaust gas line before it exits into the environment by heating it to at least 600 °C. [23] Roasting plant (1) according to one of claims 19 to 22, wherein • at least one bypass valve (11) is present, which is designed to adjust the volume flow of the roasting gas diverted through the bypass line (10) depending on the nature of an electrical signal, • and / or a fresh air flap (20) is present, which is designed to adjust the volume flow of the roasting gas supplied by the fresh air supply depending on the nature of an electrical signal, • and / or an exhaust flap (13, 14) is present, which is designed to adjust the volume flow of the roasting gas discharged through the exhaust pipe depending on the nature of an electrical signal • and / or the thermal cleaning system (15) is designed to be switched on and off depending on the nature of an electrical signal. [24] Roasting plant (1) for roasting goods such as coffee beans, cocoa beans, nuts or kernels comprising • a roasting chamber (2) with an inlet (3) and an outlet (4) for a roasting gas, • a circulating line (5) that connects the inlet (3) with the outlet (4) and through which the roasting gas circulates, • a blower (6) arranged in the circulating line (5) and designed to convey the roasting gas in the circulating line (5), • an electric heating device (7) which is designed to come into contact with the roasting gas in the circulating line (5) with a surface (36) and to transfer a heat flow to the roasting gas, wherein • the electric heating device (7) has several electric heat sources (21) which are designed to come into contact with the roasting gas in the circulating line (5) at their surfaces (36) and to transfer a heat flow to the roasting gas, wherein • an electrical power supply (22) is connected to the electric heating device (7) and is designed to supply the several electrical heat sources (21) with energy in different amounts. [25] Roasting plant (1) according to the previous claim, wherein the heating device (7) is designed such that the multiple electrical heat sources (21) can be removed and inserted separately. [26] Roasting plant (1) according to one of claims 24 to 25, wherein at least one electrical heat source (21) has a lower rated power than the other electrical heat sources (21). [27] Roasting plant (1) according to one of claims 24 to 26, in which the electrical heat sources (21) are configured to adjust the heat flow emitted by each of them depending on the nature of an electrical signal. [28] Roasting plant (1) for roasting a product such as coffee beans, cocoa beans or other seeds comprising • a roasting chamber (2) with an inlet (3) and an outlet (4) for a roasting gas, • a circulating line (5) that connects the inlet (3) with the outlet (4) and through which the roasting gas circulates, • a blower (6) arranged in the circulating line (5) and designed to convey the roasting gas in the circulating line (5), • an electric heating device (7) which is designed to come into contact with the roasting gas in the circulating line (5) with a surface (36) and to transfer a heat flow to the roasting gas, wherein • the roasting chamber (2) is designed to fluidize the roasting material. [29] Roasting plant (1) for roasting goods such as coffee beans, cocoa beans, nuts or kernels comprising • a roasting chamber (2) with an inlet (3) and an outlet (4) for a roasting gas, • a circulating line (5) that connects the inlet (3) with the outlet (4) and through which the roasting gas circulates, • a blower (6) arranged in the circulating line (5) and designed to convey the roasting gas in the circulating line (5), • an electric heating device (7) which is designed to come into contact with the roasting gas in the circulating line (5) with a surface (36) and to transfer a heat flow to the roasting gas and • a gas-fired heating device (8) designed to come into contact with the roasting gas in the circulating line (5) with a surface (36) and to transfer a heat flow to the roasting gas. [30] Roasting plant (1) according to the previous claim, in which the gas-fired heating device (8) is configured to adjust the magnitude of the heat flow emitted by it depending on the nature of an electrical signal. [31] Roasting plant (1) according to one of claims 29 to 30, wherein the gas-fired heating device (8) can be operated with methane and / or natural gas and / or propane and / or hydrogen and / or e-fuels. [32] Roasting plant (1) according to one of claims 29 or 31, wherein the gas-fired heating device (8) is arranged upstream of the electric heating device (7). [33] Roasting plant (1) for roasting goods such as coffee beans, cocoa beans, nuts or kernels comprising • a roasting chamber (2) with an inlet (3) and an outlet (4) for a roasting gas, • a circulating line (5) that connects the inlet (3) with the outlet (4) and through which the roasting gas circulates, • a blower (6) arranged in the circulating line (5) and designed to convey the roasting gas in the circulating line (5), • an electric heating device (7) which is designed to come into contact with the roasting gas in the circulating line (5) with a surface (36) and to transfer a heat flow to the roasting gas, wherein • Means (28) for supplying fresh air are available with which a volume flow of fresh air can be supplied to the roasting gas, • Means (16) for roasting gas removal are available, with which a volume flow of roasting gas can be removed from the circulating line (5), • an electronic controller is present which is designed to output an electrical signal, • a control rule is stored on the controller, which serves to determine the nature of the electrical signal depending on a control deviation, • a measuring device for measuring at least a proportion of a gas in which roasting gas is present, • the control deviation is calculated as a difference between the at least one measured proportion of the gas and a target proportion specified in the control regulation or a time-varying target proportion profile, • the means (28) for supplying fresh air are designed to adjust the size of the volume flow supplied by them depending on the nature of the electrical signal and • the means (16) for roasting gas removal are designed to adjust the size of the volume flow removed by them depending on the nature of the electrical signal. [34] Roasting plant (1) according to one of the preceding claims, wherein the electric heating device is arranged upstream of the blower.

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