Drying device for agricultural products

Abstract

Drying device for agricultural products (2), comprising a housing (3) and a blower (4) and a heating device (5) for drying air (T) conveyed by the blower (4), which is directed to at least one drying element (6) for receiving material to be dried (2), characterized in that a transfer unit (7) for the drying element (6) is assigned to the drying device (1), and that the transfer unit (7) moves the drying element (6) horizontally and / or vertically to another position above, below or next to the position of the drying element (6).

Description

[0001] The invention relates to a drying device for agricultural products, comprising a housing and a blower and a heating device for drying air conveyed by the blower, which is directed to at least one drying element with material to be dried, according to the preamble of claim 1.

[0002] Drying devices for agricultural products, such as batch or tray dryers, are known. While large quantities of agricultural products can be dried at once with such batch dryers, the resulting product quality is not always satisfactory, particularly due to variations in the drying process. Furthermore, sensitive agricultural products, such as fruits, vegetables, or medicinal plant leaves, are not well-suited to this type of dryer.

[0003] US Patent 1,539,239 A describes an apparatus for manufacturing structurally reinforced glass sheets from layers of glass with transparent cellulose material, pyroline, viscose, or casein. A layer of these materials is sandwiched between two layers of glass and bonded together in the apparatus, similar to an autoclave, by heat and pressure. Dry heat and mechanical pressure are applied to the layering material, which is not an agricultural product but an industrial product, within a container. This is achieved using a blower and a mechanical press within the container. Moisture generated in the container is removed from the pressure vessel. A multitude of heating elements are arranged within the container to heat the layering material.

[0004] The pressure and heat applied to the layered material are controlled by a control and / or regulating device.

[0005] US Patent 4,472,887 A describes a drying device for the industrial drying of fruits, nuts, or other agricultural products. The device essentially consists of two elongated drying tunnels connected end-to-end and through which drying air flows. Each tunnel has a conveyor belt, with the respective conveyor belts overlapping at the ends of the tunnels facing each other. This allows the product to fall onto the conveyor belt of the second tunnel after passing through the first tunnel. The drying process is complete after the product has passed through the second tunnel.

[0006] Each tunnel has individual chambers, largely separated from each other by walls. However, these partitions are traversed by the respective conveyor belt, allowing the products on the conveyor belt to be transported from one chamber to the next.

[0007] Each chamber is equipped with its own blower and heating unit, allowing for individual drying programs in each chamber. Temperature and humidity in each chamber can be controlled. The conveyor belt divides each chamber into an upper and a lower section. To a certain extent, it is also possible to direct drying air from one chamber to the next.

[0008] US 7 0 18 201 B1 describes a drying device in which drying air is blown alternately in one direction and in the other direction over drying carts located in the drying tunnel. The drying carts are arranged in a row behind one another in the drying tunnel.

[0009] The drying trolleys are moved in one direction through the drying tunnel, first entering a section where drying air is blown against their direction of travel. They then move into a section where drying air is blown in the direction they are moving.

[0010] The drying trolleys are moved incrementally through the drying tunnel, either pulled or pushed. The dwell time of a drying trolley in each increment depends on the load, the type of material, the desired degree of dryness, and the residual moisture content of the material being dried, and ranges from 30 minutes to 3 hours.

[0011] To achieve consistent product quality, continuous dryers are used, among other methods, and are suitable for free-flowing products such as grain. However, current dryer designs still leave something to be desired when it comes to achieving very high product quality in dried agricultural products. In particular, frequent monitoring, repositioning, or mixing of the agricultural products during the drying process is difficult or impossible with existing drying equipment.

[0012] The invention is therefore based on the objective of providing a drying device for agricultural products that achieves an increased quality of the dried products while minimizing drying time and energy consumption.

[0013] The problem is solved with a drying device having all the features of claim 1.

[0014] Preferred embodiments are set forth in the dependent claims.

[0015] By assigning a transfer unit for the drying element to the drying device, and by transferring the drying element horizontally to a position adjacent to its position (e.g., in a parallel row) or to a vertical position above or below it, a design feature allows the material to be repositioned multiple times within the drying device during the drying process and / or inspected at the transfer unit. This results in an improved drying device with regard to the quality of the dried end product. The material is dried more quickly, and its quality is improved compared to prior art drying devices.

[0016] In a simple embodiment, the drying element is essentially built in one piece and extends over approximately the length corresponding to the length of the drying device or its housing enclosing the drying chamber.

[0017] It can be advantageous, particularly when different materials are to be dried, or when the materials are to be fed into the drying device gradually, to divide the drying element into several drying segments. Drying segments can, for example, be boxes with perforated walls and bottoms.

[0018] Drying segments can also be configured as individual dryers, each with a substantially enclosed housing containing at least one fan, a heating element for warming the drying air, and one or more trays for the material to be dried. In this configuration, the operation of each dryer or dryer segment can be controlled independently by a control and / or regulating device. This allows specific materials to be dried in each drying segment, enabling the drying system to simultaneously dry a variety of different materials.

[0019] The drying device, or even individual drying segments of the drying device, may have an opening in an exhaust air duct—that is, the duct carrying the drying air after it has passed through the material being dried—which allows a fluidic connection to the surrounding environment. This opening may be closed by a flap or partially or fully open. This allows ambient air to enter the exhaust air duct, mix with it, and then be blown by the fan back into a drying air duct and directed to the material being dried.

[0020] By controlling the fan speed, the heating power of the heating device and the position of the flaps, the control and / or regulating device can control the drying of the material being dried depending on the current moisture content of the material and / or the surface temperature and / or the color of the material being dried.

[0021] It can also be advantageous to control the drying of the material to be dried according to a cycle time of the transfer unit by means of the control and / or regulating device.

[0022] The drying of the material to be dried according to time and / or temperature specifications is preferably carried out by the control and / or regulating device using a program stored in a memory.

[0023] To enable particularly thorough, controlled drying, the material to be dried can also be mixed during its passage through the transfer unit. This can be done either manually or automatically.

[0024] The invention is described below using an exemplary embodiment and explained with reference to the drawing. The drawing shows: Fig. 1. A schematic, perspective view of a drying device, Fig. 2. A view of the interior of a drying device housing with material being dried. Fig. 1; and Fig. 3 A view of a transfer unit of the drying device, as shown in Fig. 1 and Fig. 2 shown.

[0025] In Fig. Figure 1 is a schematic, perspective, partial view of a drying device 1 for agricultural products 2, for example, for tomato slices (see figure). Fig. 2) shown. The drying device 1 has a cube-shaped, truncated housing 3 made of sheet metal, which may be thermally insulated. At least one drying element 6, which is divided into many drying segments 8, is arranged in the housing 3. The drying element 6, or each drying segment 8, serves to hold and dry the material 2, as described. At least one blower 4 is provided at each drying segment 8 to draw in drying air T from the environment U and, after the drying air T has passed through a heating device 5, to convey it into a drying air duct at each drying segment 8. The blowers 4 are shown here as cross-flow blowers, but could also be axial or radial blowers. The drying air T is directed to the material 2, which is arranged one above the other on shelves 10, and dries it.

[0026] Separate blowers 4' are used to transport drying air T from one drying element 6 to the next adjacent drying element 6, with three blowers 4' being provided for each drying segment 8.

[0027] Exhaust air A is routed back to the fans 4 via exhaust air ducts 13 and dehumidified in the process. The drying element 6, formed from several drying segments 8, has a total length 1 that corresponds approximately to the length L of the drying device 1 itself.

[0028] Each drying segment 8 is operated independently of any other drying segment 8 by one or more external control and / or regulating devices 11, so that a wide variety of drying products 2 can be dried simultaneously in the drying device 1 using different drying programs. The drying air temperature in each housing 9 of each drying segment 8 may therefore differ from that in another housing 9 of another drying segment 8. To supply ambient air U to a respective blower 4, openings 14 are provided, each of which can be closed by a flap 12 or partially or fully open, with the flap 12 being controlled by the control and / or regulating device 11.

[0029] Ambient air can thus be mixed with the dehumidified exhaust air, or the respective drying segment 8 can also be operated in recirculation mode if the flap 12 closes the opening 14.

[0030] To preferably enable a cyclical movement of the drying segments 8 in the housing 3, a transfer unit 7 is arranged at preferably one end face 15 of the housing. The transfer unit 7 is in Fig. Figure 3 is shown schematically in a perspective view. With the aid of the transfer unit 7, a single drying element 6, or here the drying segments 8 shown, can be moved horizontally to an adjacent position, or as shown in Fig. As shown in 1, the material to be dried can also be transferred vertically to a position below or above it, compared to the respective starting position. At the transfer unit 7, the material 2 can also be mixed or rearranged.

[0031] The in Fig.The transfer unit 7 shown in section 3 is essentially formed from a transport floor 16 which is electromechanically vertically movable and is formed with a sliding element 17 which can move the respective drying segment 8 horizontally.

[0032] The transfer unit 7 can be operated semi- or fully automatically. Pneumatically, electrically, or hydraulically driven servomotors can be used to move the transport platform 16 and the shifting element 17.

[0033] The drying of the material to be dried 2 can be controlled by the control and / or regulating device 11 depending on the current moisture content of the material and / or the surface temperature and / or the color of the material to be dried.

[0034] The drying process can also be adapted to the cycle time of transfer unit 7.

[0035] Advantageously, the control and / or regulating device 11 can control the drying of the material to be dried 2 according to time and / or temperature specifications from a program stored in a memory of the control and / or regulating device 11. Reference symbol list 1 drying device 2. Product, drying goods 3 housings 4 (4') blowers 5 Heating system 6 drying element 7 Transfer unit 8 drying segment 9 cases, v. 8 10 Filing 11 Control and / or regulatory device 12 flap 13 Exhaust duct 14 Opening 15 End of housing 16 Transport floor 17 sliding element T Drying air 1 Length, v. 6 L length, v. 1 U surroundings A Exhaust air

Claims

[1] Drying device for agricultural products (2), with a housing (3) and with a fan (4) and a heating device (5) for drying air (T) conveyed by the fan (4), which is guided to at least one drying element (6) for receiving material to be dried (2), characterized by that the drying device (1) is assigned a transfer unit (7) for the drying element (6), and that the drying element (6) is transferred horizontally and / or vertically into another position lying above, below or next to the position of the drying element (6) by the transfer unit (7). [2] Drying device according to claim 1, characterized by that the drying element (6) has at least approximately a length (1) which corresponds to the length (L) of the drying device (1). [3] Drying device according to claim 1 or 2, characterized bythat the drying element (6) is divided into several drying segments (8) which can be handled individually. [4] Drying device according to claim 3, characterized by that each drying segment (8) has a substantially closed housing (9) in which at least one fan (4), a heating device (5) and a storage area (10) for material to be dried (2) are provided. [5] Drying device according to claim 4, characterized by that the operation of each drying segment (8) is controlled independently of another drying segment (8) by a control and / or regulating device (11). [6] Drying device according to one of claims 1 to 5, characterized bythat a flap (12) is provided between an exhaust air duct (13) for drying air (5) and the environment (4) of the drying device (1) or of each drying segment (8), which flap opens or closes an opening (14) and that outside air is guided to the fan (4) through the opening (14). [7] Drying device according to one of claims 5 or 6, characterized by that the drying of the material to be dried (2) is controlled by the control and / or regulating device (11) as a function of the current material moisture content and / or the surface temperature and / or the color of the material to be dried (2). [8] Drying device according to one of claims 5 to 7, characterized by that the drying of the material to be dried (2) is controlled by the control and / or regulating device (11) according to a cycle time of the transfer unit (7). [9] Drying device according to one of claims 5 to 8, characterized bythat the drying of the material to be dried (2) is controlled by the control and / or regulating device (11) according to time and / or temperature specifications from a program stored in a memory of the control and / or regulating device (11). [10] Drying device according to one of claims 1 to 9, characterized by that the material to be dried (2) is mixed at or by the transfer unit (7). [11] Drying device according to one of claims 1 to 10, characterized by that the transfer unit (7) is part of the drying device (1).

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