DRYING DEVICE

Description

[0001] The invention relates to a drying device for a mixture of a liquid and one or more solids.

[0002] For example, in agriculture or biogas production, significant quantities of mixtures of liquids and solids, such as (sewage) sludge, manure, or digestate, are generated that must be transported, disposed of, and / or processed. To keep transport and storage costs for these mixtures as low as possible, it is known to thicken them by deliberately reducing the liquid content in the mixtures. This can be achieved, for example, by at least partially evaporating this liquid content.

[0003] For thickening by partial evaporation of the liquid portion of a mixture, a generic drying device can be used, for example, which comprises a receiving container for receiving the mixture, a rotor arranged with a portion of its circumference in the receiving container, and a drive device for rotating the rotor. Such a drying device is known, for example, from DE 10 2016 105 538 A1. In the drying device therein, the rotor is equipped with a plurality of flat drive elements that have a radial orientation or an orientation inclined to the radial with respect to the rotational axis of the rotor, wherein at least some and preferably all of the drive elements are provided with a plurality of through openings.As a result of the rotation of the rotor, individual entraining elements continuously immerse themselves in the mixture to be thickened, entraining a portion of it. The mixture suspended on the entraining elements is subjected to increased evaporation on the portion of the rotor circumference not immersed in the mixture, which is due to the large-area, thin-layer distribution on the entraining elements. This evaporation effect is further enhanced by the exposure of the mixture suspended on the entraining elements to an air stream generated by a fan, which may also be heated.

[0004] To generate the drying gas flow, a device comprising one or more fans and, if appropriate, a heat exchanger is attached to the frame 1 on one side of the frame at the level of the rotor section located outside the receiving container. The drying gas flow is generated by means of the at least one fan, which is oriented approximately perpendicular to the rotor's rotational axis and thus flows through the rotor section located outside the receiving container transversely to its rotational axis and is discharged through an opening on the rear side.

[0005] The operation of the drying device requires recurring cleaning, maintenance, and / or repair work on the fans, the existing heat exchanger, the rotor, and / or the interior of the receiving container. However, access is relatively limited due to the fans and heat exchanger, and requires increased effort, as the fans and heat exchanger must be dismantled if work on the rotor or inside the receiving container is required.

[0006] In the drying device of JP S56 90694 U, the outlet opening is arranged in a hinged frame that can be pivoted from a closed position to an open position. A similar design is known from JP S56 103193 U. Furthermore, DD 288 211 A5 discloses a drum dryer with a loading door and an opposite unloading door, each of which can be opened and closed.

[0007] Furthermore, EP 3 163 239 A1 discloses a drying device according to the prior art.

[0008] The invention is therefore based on the object of facilitating cleaning, maintenance and repair work on the drying device.

[0009] This object is achieved by means of a drying device according to claim 1. Advantageous embodiments of the drying device according to the invention are the subject matter of the dependent claims and emerge from the following description of the invention.

[0010] The drying device according to the invention for a mixture of a liquid and one or more solids comprises a frame, a receiving container arranged in the frame with an inlet and an outlet for the mixture, and a rotor rotatably mounted on the frame and arranged with a portion of its circumference in the receiving container, said rotor having a plurality of flat drive elements. The rotor is driven by a drive device to rotate about a rotor axis.The frame is designed to be closed, at least in the area above the receiving container, in the manner of a housing and provides at least one inlet opening on a side aligned parallel to the rotor axis for a drying gas flow through the housing. The at least one inlet opening is arranged in a folding frame that can be pivoted from a closed position to an open position for checking, assembling, repairing, or cleaning the drying device. Furthermore, at least one fan is mounted on an outer side of the folding frame in the area of ​​the at least one inlet opening, and at least one heat exchanger is provided in the folding frame and is mounted in the flow path of the drying gas flow. The folding frame is further designed as a double folding frame with a first folding frame part for holding the at least one fan and a second folding frame part for holding the heat exchanger.

[0011] The blower connected to at least one inlet opening can be easily pivoted away with the aid of the folding frame in order to enable uncomplicated and quick access to the receiving container and / or rotor.

[0012] According to a preferred embodiment of the invention, the folding frame, in the open position, provides an assembly and cleaning opening in the frame with a clear width (in the direction of the rotation axis) that is greater than the length of the drive elements in the direction of the rotation axis. Furthermore, the folding frame can be pivoted by at least 90°. This significantly simplifies the removal or replacement of the long drive elements. Ideally, the individual drive elements are simply inserted and secured into the corresponding guide rails on the rotor, allowing them to be quickly inserted or removed.

[0013] By mounting the fan on the outside of the folding frame in the area of ​​at least one inlet opening, this fan is also accessible from the other (inside) side for maintenance or repair work by opening the folding frame.

[0014] According to a further embodiment of the invention, it is particularly advantageous if the first folding frame part is arranged so that it can be pivoted by at least 90°, either individually or together with the second folding frame part, so that either the fan mounted on the first folding frame part or the heat exchanger mounted on the second folding frame part can be inspected from both sides, allowing cleaning or maintenance work to be carried out quickly and effectively. However, if work on the rotor or inside the receiving container is required, both folding frames can also be pivoted together into the open position.

[0015] In a preferred embodiment, the first folding frame part has a first pivot axis and the second folding frame part has a second pivot axis, which are arranged parallel to one another. The second folding frame part can then be mounted on the frame so as to be pivotable about the second pivot axis directly or indirectly, while the first folding frame part is mounted on the second folding frame part so as to be pivotable about the first pivot axis.

[0016] If work is required in the area of ​​the receiving container or rotor, it is sufficient for both folding frame sections to be pivoted together around the second pivot axis into the open position. However, if work is only required on the fans or the front of the heat exchanger, it is sufficient to open only the first folding frame and pivot it around the first pivot axis.

[0017] The invention is explained in more detail below using an exemplary embodiment illustrated in the drawings. In the drawings: Fig. 1 : the drying device according to the invention in a side view; Fig. 2 : the drying device with closed folding frame in a first perspective view, Fig. 3 : the drying device with opened folding frame in a second perspective view and Fig. 4 : the drying device with open folding frame in a top view.

[0018] The drying device shown in the drawings comprises a frame 1, within which a rotor 2 is rotatably mounted. A rotating drive of the rotor 2 can be achieved by means of a drive device 3 (see Fig. 2 ), which may, for example, comprise an electric motor which can act directly or with the interposition of a transmission gear on a central drive shaft 4, the longitudinal axis of which corresponds to the axis of rotation 5 of the rotor 2.

[0019] The frame 1 further integrates a receiving container 6, which has a half-shell-shaped container shell 6a, the two (longitudinal axial) ends of which are closed by means of boundary walls 7 ( Fig. 2 ). The receiving container 6 is positioned below (relative to the direction of gravity in an intended operating position of the drying device) the rotor 2, wherein the rotor 2 is arranged partially, preferably approximately half, within the receiving container 6.

[0020] The internal volume defined by the receiving container 6 is fluidly connected to an inlet 8 and an outlet 9, through which a mixture 10 of a liquid and one or more solids can be supplied and discharged. The inlet 8 serves to supply a new mixture 10 that is still to be thickened, while the mixture 10 thickened by means of the drying device according to the invention can be discharged via the outlet 9 ( Fig. 4 ). The inlet 8 and the outlet 9 are spaced apart from one another along the rotational axis 5 of the rotor 2 and are integrated opposite one another in the boundary walls 7 of the receiving container 6. One or more pumps or conveying devices (not shown) can be provided for supplying and discharging the mixture 10.

[0021] On one side of the frame 1, at the level of the section of the rotor 2 located outside the receiving container 6, a device is attached to the frame 1. The device comprises a plurality of fans 11 (specifically two here) and a heat exchanger 12. By means of the fans 11, which can be driven by an electric motor, for example, an air flow can be generated which is oriented approximately perpendicular to the rotational axis 5 of the rotor 2 and thus flows through the section of the rotor 2 located outside the receiving container 5 transversely to its rotational axis 5 and is discharged at the rear via an opening (not shown). The air flow first flows through the heat exchanger 12, whereby it is heated by a transfer of thermal energy from a heat exchange medium guided within the heat exchanger 12 and conveyed through the heat exchanger 12, for example, by a circulating pump (not shown).

[0022] The fans 11 and the heat exchanger 12 are mounted on a folding frame 13, which is designed as a double folding frame with a first folding frame part 14 for holding the two fans 11 and a second folding frame part 15 for holding the heat exchanger 12. The first folding frame part 14 is mounted on the second folding frame part 15 about a first pivot axis 16, while the second folding frame part 15 is pivotally mounted on a frame part 18 of the frame about a second pivot axis 17. In order to achieve the most directed flow through the rotor 2 possible, the frame part 18 of the housing 13 can preferably also have a flow-guiding function.

[0023] The first folding frame part 14 can be rotated individually or together with the second folding frame part 15 by at least 90° between a closed position ( Fig. 1 , 2 ) and an open position ( Fig.3 , 4) so that either the blower 11 mounted on the first folding frame part 14 or the heat exchanger 12 mounted on the second folding frame part 15 can be inspected from both sides, and any cleaning or maintenance work can be carried out quickly and effectively. However, if work is required on the rotor 2 or inside the receiving container 6, both folding frames 14, 15 can also be pivoted together into the open position.

[0024] In the Fig. 3 and 4 For reasons of clarity, the fans 11 are not shown. However, one can see in Fig.3 two inlet openings 19 in the area of ​​which the two fans 11 are mounted on the outside of the first folding frame part 14 ( Fig. 1 and 2 ).

[0025] The rotor 2 comprises two end walls 20 which define an internal volume of the rotor 2 at the front and which are arranged by means of a plurality of plate-shaped driving elements 21 which are distributed evenly over the outer circumference of the rotor 2 and which are aligned inclined to the radial direction with respect to the rotation axis 5 in the direction of rotation of the rotor 2 (cf. in particular Fig. 1 ), are connected to one another. The plate-shaped driving elements 21 are preferably rectangular, with their longitudinal sides running parallel to the rotor axis 5 being several times longer than the width of the driving elements 21.

[0026] Due to the comparatively large total area formed by the plate-shaped entrainment elements 21 in total and which is available for entrainment of the mixture 10 to be thickened and is surrounded by the air flow, a correspondingly good drying or evaporation effect for the liquid portion of the mixture 10 can be achieved.

[0027] During operation of the drying device, the rotor 2 is rotated by means of the drive device 3, whereby another section of the rotor 2 is continuously immersed in the mixture 10 held within the receiving container 6. The entraining elements 15 thus wetted with the mixture 10 are then moved along the section of the circumference of the rotor 2 not located in the receiving container 6, wherein the heated air flow flows around and through them, causing a portion of the liquid in the mixture 10 to evaporate. This achieves the desired thickening of the batch of mixture 10 contained within the receiving container 6. This continues until the batch of mixture 10 contained in the receiving container 6 has reached a defined consistency or viscosity.Then, the corresponding batch of the mixture 10 can be discharged from the receiving container 6 via the outlet 9 and a new batch can be fed in via the inlet 8, which can then be thickened in a corresponding manner by operating the drying device.

[0028] Furthermore, by designing the entraining elements 21 with a plurality of through-openings, it is possible to ensure that the gas flow intended for drying the mixture 10 can flow not only through the spaces formed between the entraining elements 21 but also through the entraining elements 21 themselves and thus also through the mixture 10 adhering to them, whereby the drying effect of the drying device can also be significantly improved compared to entraining elements that cannot be passed through. Regarding further design options for the rotor 2 and the entraining elements 21, reference is hereby expressly made to DE 10 2016 105 538 A1.

[0029] The desired consistency or viscosity of the mixture 10 can be determined, for example, by the mixture 10 falling below a defined fill level within the receiving container 6. To determine the fill level, the drying device can have a corresponding fill level measuring device (not shown), which can comprise, for example, a radar device. Determining the fill level or the desired consistency can alternatively or additionally be based on weighing the receiving container 6 or the mixture 10 contained in the receiving container 6. The operation of the drying device, including the supply and removal of the various batches of the mixture 10 and, if necessary, an interruption of the rotating drive of the rotor 2 during batch changes, can thus be automated.

[0030] The thermal energy transferred to the air flow in the heat exchanger 12 preferably represents waste heat from an exothermic process, preferably carried out in the vicinity of the drying device, such as the combustion of biogas or another fuel for electricity and / or heat generation.

[0031] Out of Fig. 3 It can be seen that, in order to hold the carrier elements 21, guide rails 22 are arranged on the opposite surfaces of the two end walls 20, into which the carrier elements 21 can be inserted and secured. Fig. 3 shows such a carrier element 21 shortly before assembly. The frame part 18 of the frame 1 provides for this purpose when the folding frame 13 is opened ( Fig. 3) creates an assembly and cleaning opening 23 whose clear width is greater than the length of the drive elements 21, so that the drive elements 21 can be easily fed through the assembly and cleaning opening 23 and inserted and secured into the associated guide rails 22. Accordingly, the drive elements 21 can also be very easily removed through the assembly and cleaning opening 23.

[0032] The folding frame 13 thus enables easy access for work in the area of ​​the receiving container 6 or rotor 2. In addition, maintenance and repair work on the blower 11 and the heat exchanger is possible through the two folding frame parts 14, 15 on both the front and the rear.

Claims

1. A drying device for a mixture (10) of a liquid and one or more solids, comprising - a frame (1), - a receiving container (6), which is arranged in the frame (1) and comprises an inlet (8) and an outlet (9) for the mixture (10), - a rotor (2), which is rotatably mounted on the frame (1), is arranged with a portion of its circumference in the receiving container (6), and comprises a plurality of flat entraining elements (21), - a drive device (3) for rotatably driving the rotor (2) about a rotor shaft (5), - the frame (1) being configured to be closed, in the manner of a housing, at least in the region above the receiving container (6) and at least one inflow opening (19) for a drying gas stream to flow through the housing is provided on a side oriented in parallel with the rotor shaft (5), characterized in that the at least one inflow opening (19) is arranged in a hinged frame (13), which is pivotable from a closed position into an open position for checking, mounting, repairing, or cleaning the drying device, - at least one fan (11) being mounted on an outer side of the hinged frame (13) in the region of the at least one inflow opening (19), - at least one heat exchanger (12), which is mounted in the flow path of the drying gas stream, further being provided in the hinged frame (13), and - the hinged frame (13) is configured as a double hinged frame comprising a first hinged frame part (14) for holding the at least one fan (11) and a second hinged frame part (15) for holding the heat exchanger (12).

2. The drying device according to claim 1, characterized in that in the open position, the hinged frame (13) opens a mounting and cleaning opening (23) in the frame (1) with a clear width that is greater than the length of the entraining elements (21) in the direction of the rotational shaft (5).

3. The drying device according to claim 1, characterized in that the hinged frame (13) is pivotable by at least 90°.

4. The drying device according to claim 1, characterized in that the first hinged frame part (14) is arranged to be pivotable by at least 90° individually or together with the second hinged frame part (15).

5. The drying device according to claim 1, characterized in that the first hinged frame part (14) has a first pivot axis (16) and the second hinged frame part (15) has a second pivot axis (17), which axes are oriented in parallel with one another.

6. The drying device according to claim 5, characterized in that the second hinged frame part (15) is held indirectly or directly on the frame (1) so as to be pivotable about the second pivot axis (17) and the first hinged frame part (14) is mounted on the second hinged frame part (15) so as to be pivotable about the first pivot axis (16).