Roasting assembly for bulk plant material and method for operating a roasting assembly

Abstract

The invention relates to a roasting assembly for bulk plant material (16), having a housing assembly (4) which has at least one roasting device (6) with an interior (10) in which the bulk material (16) is to be roasted, a heating assembly (8; 9) which permits heat to be transported by means of a heating fluid to the bulk material (16) in the interior (10), a solid material separating device for cleaning waste gases from the roasting device (6), and a control assembly (20) for controlling a roasting process, wherein in order to implement different heating modes and different heating powers, the heating assembly (8; 9) has an electric heating element (22; 23) and a gas combustion device (24; 25) which are each connected for control purposes to the control assembly (20). The invention further relates to a method for operating such a roasting assembly (6).

Description

[0001] DESCRIPTION

[0002] Roasting arrangement for bulk vegetable material and method for operating a roasting arrangement

[0003] The invention relates to a roasting arrangement for bulk plant material, comprising a housing arrangement that includes at least one roasting device with an interior space in which the bulk material is to be roasted, a heating arrangement that enables heat transfer to the bulk material in the interior space by means of a heating fluid, a solids separation device for cleaning exhaust gases from the roasting device, and a control arrangement for controlling a roasting process. Furthermore, the invention relates to a method for operating such a roasting arrangement.

[0004] Roaster systems for roasting bulk plant materials are well known in the art. In this context, reference is made, by way of example, to DE 10 2004 038 730 B3, which discloses a roaster system used in industrial applications. Such roaster systems typically utilize a gas burner as a heating system for heating a heating fluid. Particularly in light of the scarcity of energy resources and the rapid changes in the costs of individual energy sources, the operation of an energy-intensive roaster system can lead to extremely high energy costs, which are also unforeseeable.

[0005] The object of the invention is therefore to avoid the aforementioned disadvantages in a simple and cost-effective manner. This object is achieved by a roaster arrangement according to the invention in that the heating arrangement has an electric heating element and a gas combustion device for implementing different heating modes and different heating outputs, each of which is control-technically connected to the control arrangement. Heating mode here refers to the form in which the heating energy is provided. This can be purely electrical, purely gas, or in any mixed form, whereby the heating mode can also be changed before or during the implementation of a roasting recipe. This makes it possible in principle to operate the roaster arrangement according to the invention with electricity in a simple manner.Particularly when using renewable energies such as solar energy and / or wind energy, it must be assumed that there will be operating times during which electricity from these renewable energies will not be available in sufficient quantities. In this case, the heating arrangement can easily be additionally operated with gas. The bulk material in the interior can be roasted convectively and / or conductively and / or by radiant heat using the heating fluid. In this context, the heating arrangement refers to all adjustable means that ensure heating of the bulk material, such as the electric heating element, the gas combustion device, as well as fans, flaps, etc. Interior parts include, for example, the interior walls and the agitator, or even a drum or bowl. There are a multitude of different roaster arrangements, the interior of which can have very different designs.

[0006] In a first embodiment, the electric heating element is fluidically connected to a first heating fluid line and the gas combustion device is fluidically connected to a second heating fluid line, wherein the first and second heating fluid lines are fluidically connected to a third heating fluid line, which is fluidly connected to the roasting device. In this case, the first and second heating fluid lines can be fluidically connected to the third heating fluid line via a heating fluid connecting element. Advantageously, a heating mode adjustment flap can be provided in the heating fluid connecting element, making it possible to quickly change the heating mode. Mixed operation is also possible. In order to minimize possible flow resistance for the heating fluid, the connecting element can particularly advantageously be designed as a Y-heating fluid connecting element.To preheat the gas burner, a connecting line can be provided between the electric heating element and the gas burner. It is advantageous if a check valve is provided in the connecting line to prevent heating gas from reaching the electric heating element.

[0007] Alternatively, in a second embodiment, the electric heating element and the gas combustion device can be fluidically arranged in series, wherein the gas combustion device is fluidically connected to the third heating fluid line to the roasting device.

[0008] Particularly advantageously, at least a base heating load can be generated by the electric heating element, and additional heating loads can be generated by the electric heating element and / or the gas combustion device. This allows for optimal use of renewable energy, in particular.

[0009] In a particularly advantageous embodiment, the heating arrangement roasts the bulk material in the interior using the heating fluid convectively and / or conductively and / or by radiant heat. In a further advantageous embodiment, a vacuum blower can be provided, arranged downstream of the roasting device in the direction of flow of the heating fluid, to extract the heating fluid from the roasting device. The negative pressure present in the roasting device ensures a uniform supply of heating fluid, regardless of the heating mode.

[0010] In a particularly advantageous manner, an air supply fan is provided in front of the electric heating element on a side of the electric heating element facing away from the first heating fluid line.

[0011] Particularly advantageously, the roasting device comprises at least one sensor element for monitoring the roasting process. This allows, in particular, active control of the roasting process either by the user themselves, upon receiving a message from the control system, or automatically by the control system.

[0012] Advantageously, the heating arrangement is fluidically connected to a first exhaust gas recirculation line in order to recirculate purified exhaust gas to the heating arrangement, thereby reducing emissions and heating the heating fluid, thus saving energy. Both the electric heating element and the gas combustion device can be fluidically connected to the first exhaust gas recirculation line via a second and a third exhaust gas recirculation line via a Y-type exhaust gas connection element. To ensure optimal supply of the recirculated exhaust gas, an exhaust gas recirculation flap can be provided in the Y-type exhaust gas connection element.

[0013] For particularly precise heating fluid adjustment, which is desirable for some roasting recipes, a heating fluid bypass line can be provided to the exhaust line with the solids separation device. A heating fluid adjustment cap can be provided in the heating fluid bypass line.

[0014] The object is also achieved by a method for operating such a roasting arrangement, in which a roasting mode is selected in the control arrangement (20) depending on a roasting recipe.

[0015] In a particularly advantageous manner, in each roasting mode, a required base heating power load is generated by the electric heating element and additional heating power loads are generated by the electric heating element and / or the gas combustion device.

[0016] Advantageously, before changing the heating mode, the third heating fluid line and the roasting device are purged with supply air. The supply air for the purging process can be provided by the supply air fan of the electric heating element.

[0017] The invention is explained in more detail with reference to a drawing, in which: Figure 1 shows a schematic representation of a roaster arrangement according to the invention with a first embodiment of an arrangement of electric heating element and gas burning device of a heating arrangement, and

[0018] Figure 2 is a schematic detailed view of a second embodiment of an arrangement of electric heating element and gas burning device of a heating arrangement.

[0019] Figure 1 shows a schematic representation of a roaster assembly 2 according to the invention, which is well known in the art. Such a roaster assembly 2 has a housing assembly 4 containing at least one roasting device 6, a heating assembly 8 for heating an interior space 10 of the roasting device 6, a solids separation device 12 for cleaning exhaust gases from the interior space 10 of the roasting device 6, and, in the present exemplary embodiment, a cooling assembly 14 for cooling a bulk plant material to be roasted, here coffee beans 16. The unroasted coffee beans 16 are fed into the interior space 10 of the roasting device 6 via a hopper inlet 18. A control assembly 20 is also provided, which controls and regulates a roasting process and a cooling process.

[0020] According to the invention, the heating arrangement 8 initially comprises an electric heating element 22 and a gas combustion device 24, which, by heating an incoming air, provide a heating fluid which, in the case of the electric heating element 22, is heating air and, in the case of the gas combustion device 24, is heating gas. In the first exemplary embodiment shown in Figure 1, a first heating fluid line 26 adjoins the electric heating element 22, and a second heating fluid line 28 adjoins the gas combustion device 24. These second heating fluid lines are fluidically connected to a third heating fluid line 32 via a Y-shaped heating fluid connecting element 30, the third heating fluid line 32 conveying the heating fluid to the roasting device 6.

[0021] On a side of the electric heating element 22 facing away from the first heating fluid line 26, an air supply fan 34 is provided in front of the electric heating element 22 to ensure a uniform flow of heating air. Furthermore, reliable cooling of the electric heating element 22 is ensured in all operating situations. The gas combustion device 24 also has a fan 36 in a known manner. Furthermore, a connecting line 40 with a check valve 42 is provided from the electric heating element 22 to the air supply inlet 38 of the fan 36 to preheat the air supply to the gas combustion device 24. To enable the setting of different heating modes, a heating mode adjustment flap 44 is also provided in the Y-shaped heating fluid connecting element 30.The third heating fluid line 32 also has a heating fluid flap 46, which, together with an exhaust flap 48 and a vacuum fan 50 as part of the heating arrangement 8, together with the aforementioned means 22-44, influences a heating fluid mass flow, an exhaust gas mass flow, and a temperature of the roasting process. In the present embodiment, heat is thus transferred to the coffee beans 16 both convectively and conductively, as well as through radiant heat.

[0022] In the present embodiment, the cooling arrangement 14 consists of a cooling device 52 with a flat-bed cooler 54, onto which the coffee beans 16 are poured via an outlet opening 56 of the roasting device 6. The flat-bed cooler 54, together with a hood arrangement 58, encloses a cooling chamber 60 into which cooling air is blown by a cold air device 62. A bulk material outlet arrangement 64 and a cooling air discharge device 66 are connected to the cooling device 52 in a known manner.

[0023] In the present embodiment, the temperature of the coffee beans 16 in the interior 10 of the roasting device 6 is monitored by a sensor element 67, which is advantageously designed to be contactless.

[0024] As already described above, an exhaust gas purification device 12 is provided, which purifies the exhaust gas in a known manner and can release it into the environment. However, a first exhaust gas recirculation line 68 is also provided, which is fluidly connected to a second and a third exhaust gas recirculation line 78, 80 via a Y-shaped exhaust gas connecting element 74 with an exhaust gas recirculation flap 76 in order to recirculate exhaust gas to the electric inlet area 79 of the electric heating element 22 and / or to a gas inlet area 81 of the gas combustion device 24 for preheating the respective supply air.

[0025] In order to provide an additional setting option for quick adjustment within the framework of a roasting recipe, a heating fluid bypass line 82 with a heating fluid adjustment flap 84 is also provided to the exhaust gas cleaning device 12.

[0026] Figure 2 now shows a detailed view of a second embodiment of a roaster assembly 3, in which an alternative arrangement of electric heating element 23 and gas combustion device 25 of a heating assembly 9 is provided. All other components of the roaster assembly 2 remain unchanged. Although Figure 3 shows only a detailed view with a few components, the reference numerals 3 for roaster assembly and 9 for heating assembly are introduced to represent the differences from the roaster assembly 2 and heating assembly 8 shown in Figure 1. Here, an electric heating element 23 and a gas combustion device 25 are arranged in series via a heating fluid connection line 86, with the gas combustion device being fluidly connected to the third heating fluid line 32 to the roaster assembly 6. Here, too, as indicated by the dashed line, both the electric heating element 23 and the gas combustion device 25 are connected to the control assembly 20.In the present embodiment, the electric inlet area 79 of the electric heating element 23 is connected to the first exhaust gas recirculation line 68. This also allows exhaust gas recirculation to the gas combustion device 25.

[0027] In this context, it should be noted that exhaust gas recirculation is not absolutely necessary. In particular, it is also conceivable to connect only the electric heating element 22; 23 to the exhaust gas recirculation line 68.

[0028] In order to be able to control the roaster arrangement 2; 3 as flexibly as possible, in the present embodiment the control device 20 is connected to a plurality of components, such as the electric heating element 22; 23, the gas combustion device 24; 25, the roasting device 6, the sensor element 67 and the various flaps and blowers or fans.

[0029] With such a roaster arrangement 2; 3, a corresponding roasting mode can be selected based on a roasting recipe stored in the control arrangement. In each roasting mode, a required base heating power load can be generated by the electric heating element 22; 23. Required additional heating power loads are then generated by the electric heating element 22; 23 and / or by the gas combustion device 24; 25, depending on the prevailing energy constraints.

[0030] It has proven particularly effective to flush the third heating fluid line 32 and the roasting device 6 with supply air before changing the roasting recipe. The supply air for the flushing process can be provided by the supply air fan 34 of the electric heating element 22; 23.

Claims

PATENT CLAIMS 1. Roasting arrangement for bulk vegetable material (16) with a Housing arrangement (4) which has at least one roasting device (6) with an interior space (10) in which the bulk material (16) is to be roasted, a heating arrangement (8; 9) which enables heat to be transported to the bulk material (16) in the interior space (10) by means of a heating fluid, a solids separation device for cleaning exhaust gases from the roasting device (6), and a control arrangement (20) for controlling a roasting process, characterized in that the heating arrangement (8; 9) has an electric heating element (22; 23) and a gas combustion device (24; 25) for implementing different heating modes and different heating outputs, which are each connected to the control arrangement (20) for control purposes.

2. Roaster arrangement according to claim 1, characterized in that the electric heating element (22) is fluidically connected to a first heating fluid line (26) and the gas combustion device (24) is fluidically connected to a second heating fluid line (28), wherein the first and second heating fluid lines (26, 28) are fluidically connected to a third heating fluid line (32) which is fluidically connected to the roasting device (6).

3. Roaster arrangement according to claim 2, characterized in that the first and the second heating fluid line (26, 28) are fluidly connected to the third heating fluid line (32) via a heating fluid connecting member (30).

4. Roaster arrangement according to claim 3, characterized in that a heating mode adjustment flap (44) is provided in the heating fluid connecting member (30).

5. Roaster arrangement according to claim 3 or 4, characterized in that the heating fluid connecting element (30) is designed as a Y-heating fluid connecting element.

6. Roaster arrangement according to one of claims 2 - 5, characterized in that a connecting line (40) is provided between the electric heating element (22) and the gas combustion device (24).

7. Roaster arrangement according to claim 6, characterized in that a check valve (42) is provided in the connecting line (40).

8. Roaster arrangement according to claim 1, characterized in that the electric heating element (23) and the gas combustion device (25) are fluidically arranged in series, wherein the gas combustion device (25) is fluidically connected to the third heating fluid line (32) to the roasting device (6).

9. Roaster arrangement according to one of the preceding claims, characterized in that at least one basic heating power load can be generated by the electric heating element (22; 23) and additional heating power loads can be generated by the electric heating element (22; 23) and / or the gas combustion device (24; 25).

10. Roaster arrangement according to one of the preceding claims, characterized in that the heating arrangement (8; 9) heats the bulk material (16) in the interior (10) by means of the heating fluid roasted convectively and / or conductively and / or by radiant heat.

11. Roaster arrangement according to one of the preceding claims, characterized in that a vacuum blower (50) arranged behind the roasting device (6) as seen in the flow direction of the heating fluid is provided for sucking the heating fluid out of the roasting device (6).

12. Roaster arrangement according to one of the preceding claims, characterized in that an air supply fan (16) is provided in front of the electric heating element (22; 23) on a side of the electric heating element (22; 23) facing away from the first roasting device (6).

13. Roaster arrangement according to one of the preceding claims, characterized in that the roasting device (6) has at least one sensor element (67) for monitoring the roasting process.

14. Roaster arrangement according to one of the preceding claims, characterized in that the heating arrangement (8; 9) is fluidly connected to a first exhaust gas recirculation line (68).

15. Roaster arrangement according to claim 14, characterized in that both the electric heating element (22; 23) and the gas combustion device (24; 25) are each connected via a second and a third exhaust gas recirculation line (78, 80) via a Y-exhaust connecting element (74) is fluidly connected to the first exhaust gas recirculation line (68).

16. Roaster arrangement according to claim 15, characterized in that an exhaust gas recirculation flap (76) is provided in the Y-exhaust gas connecting member (74).

17. Roaster arrangement according to one of the preceding claims, characterized in that a heating fluid bypass line (82) to an exhaust gas line with the solids separation device (12) is provided.

18. Roaster arrangement according to claim 17, characterized in that a heating fluid adjustment cap (84) is provided in the heating fluid bypass line (82).

19. A method for operating a roasting arrangement according to one of the preceding claims, characterized in that a roasting mode is selected in the control arrangement (20) depending on a roasting recipe.

20. A method for operating a roaster arrangement according to claim 1, characterized in that in each roasting mode a required base heating power load is generated by the electric heating element (22; 23) and additional heating power loads are generated by the electric heating element (22; 23) and / or the gas combustion device (24; 25).

21. A method for operating a roasting arrangement according to claim 19 or 20, characterized in that before a change of the heating mode, the third heating fluid line (32) and the roasting device (6) are flushed with supply air.

22. A method for operating a roaster arrangement according to claim 21, characterized in that the supply air for the rinsing process is provided by the supply air fan (34) of the electric heating element (22; 23).

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