Continuous drying device

Abstract

The invention relates to a continuous drying device (2) for drying hygroscopic material to be dried, having a drying chamber (4) for receiving the material to be dried, having conveying means for conveying the material to be dried from an inlet (6) to an outlet (8) of the drying chamber (4) in a conveying direction (10) during the drying process, and having climate control means for setting a drying climate in the drying chamber (4) during the operation of the drying device (2), in such a way that multiple climate zones (12 to 22), in which different zone climates can be set, are set, or take effect, are formed in succession in the conveying direction.

Description

[0001] Channel drying device

[0002] The invention relates to a channel drying device of the type mentioned in the preamble of claim 1 for drying hygroscopic material.

[0003] Drying devices for drying hygroscopic drying material are generally known, for example from DE 3425642 C1, DE 3443915 C2, DE 10 2000 5030 501 A1, DE 10 2008 013 012 B4, DE 10 2010 054 493 B4, EP 0 292 717 B1, EP 1 659 218 A1 and EP 2 792 938 A2, and can be used in particular for drying sawn timber.

[0004] DE 10 2016 124 258 B4 discloses a channel drying device having the features of the preamble of claim 1.

[0005] The invention is based on the object of specifying a channel drying device of the type mentioned in the preamble of claim 1, which is further improved compared to the known channel drying device.

[0006] This object is achieved by the invention defined in claim 1.

[0007] Advantageous and expedient developments of the invention according to claim 1 are specified in the subclaims.

[0008] The invention provides a channel drying device, hereinafter also referred to as a drying device for short, which has a drying chamber for receiving the material to be dried and conveying means for conveying the material to be dried from an inlet to an outlet of the drying chamber during the drying process in a conveying direction. The drying device further comprises air conditioning means for adjusting a drying climate in the drying chamber of the drying chamber during operation of the drying device, such that a plurality of climate zones are formed successively in the conveying direction, in which different zone climates can be adjusted, are adjusted, or are adjusted.

[0009] According to the invention, the drying device has at least one flow channel that can be connected to at least some of the drying zones via closable flow openings, wherein each flow opening is assigned a shut-off device for completely or partially closing the respective flow opening. Each shut-off device is connected to a central control device that is designed and programmed such that, during the drying process, drying air from at least one climate zone can be introduced or is introduced into at least one other climate zone by opening flow openings of the flow channel to adjust the drying climate in at least one drying zone.

[0010] The invention enables the exchange of drying air between the different climate zones in the drying chamber via one or more flow channels. For example, during the drying process, warm and humid drying air may be present in one climate zone due to moisture released by the material being dried. This drying air can then be introduced via a flow channel into another climate zone, where such warm and humid drying air is required according to the drying process.

[0011] According to the invention, not only can drying air be directed from one climate zone to another. Rather, it is also possible to mix drying air from several climate zones in one flow channel and direct it to another climate zone. In this way, drying air with a desired relative humidity and air temperature can be provided for introduction into a climate zone, optionally with the addition of fresh air.

[0012] This results in increased effectiveness compared to known channel drying devices, for example and in particular with regard to the energy consumption of the device, the drying time and an optimization of the drying process. Since, for example, warm drying air is introduced from one climate zone into another climate zone, the energy stored in the drying air can be used to dry the material to be dried in this climate zone. Internally, energy consumption is thus optimized within the device, for example, because energy supplied to a climate zone in the form of warm drying air from another climate zone does not have to be provided by a heating device. If excess heat energy from one climate zone is not needed in another climate zone, this heat energy can be recovered via a heat exchanger.

[0013] A further advantage of the invention is that, due to the high flexibility in exchanging drying air between climate zones, duplicate units of the drying device can be avoided. This leads to a lower investment volume when purchasing the drying device and a lower susceptibility to errors during operation. This saves both acquisition and operating costs.

[0014] Depending on the respective requirements and circumstances, more than one flow channel can be provided according to the invention. For example, and in particular, the drying device can have a first flow channel on the supply air side and a first flow channel on the exhaust air side.

[0015] In particular, at least two flow ducts can be provided on both the supply air and exhaust air sides. The first flow duct on the supply air side can serve to establish a flow connection between the climate zones on the supply air side, while the second flow duct on the supply air side can serve to establish a flow connection between the climate zones and a fresh air supply. Correspondingly, the first flow duct on the exhaust air side can serve to establish a flow connection between the climate zones on the exhaust air side, while the second flow duct on the exhaust air side can serve to establish a flow connection to the outside air.

[0016] According to the invention, more than four channels can also be provided for an exchange of drying air between the climate zones.

[0017] In claim 19, a method for drying hygroscopic material to be dried is specified, in which a drying device is used which

[0018] - a drying chamber, which has a drying space for receiving the material to be dried,

[0019] - Conveying means for conveying the material to be dried from an inlet to an outlet of the drying chamber in a conveying direction and - Air conditioning means for setting a drying climate in the drying space of the drying chamber during operation of the drying device, such that a plurality of climate zones are formed successively in the conveying direction, wherein during operation of the drying device in the climate zones different zone climates can be set, are set or are set.

[0020] According to the invention, a drying device is used with at least one flow channel that can be connected to at least some of the climate zones via closable flow openings, wherein each flow opening is assigned a shut-off device for completely or partially closing the respective flow opening. According to the invention, the shut-off devices are controlled by a control device during the drying process in such a way that, by opening flow openings of the flow channel, the drying climate in at least one climate zone is adjusted by introducing drying air from at least one climate zone into at least one other climate zone.

[0021] The same advantages and properties arise as with the drying device according to the invention.

[0022] Preferably, a drying device according to the invention is used to carry out the drying process according to the invention.

[0023] It is clear that the assignment of a flow channel to the supply air side or exhaust air side changes when the flow direction in the drying chamber changes due to reversing the drying device's recirculation fans. The same applies when the flow direction changes in the conveying direction of the material being dried from one climate zone to the next.

[0024] The invention is explained in more detail below with reference to the attached, highly schematic drawing using an exemplary embodiment. It will be apparent to a person skilled in the art that the individual features of an exemplary embodiment each develop the exemplary embodiment on their own, i.e. independently of the other features, so that it will be apparent to a person skilled in the art that all of the features described, shown in the drawing and claimed in the patent claims, taken individually and in any technically reasonable combination with one another, form the subject matter of the invention, regardless of their summary in the patent claims and their references, as well as regardless of their specific description or representation in the drawing. The subject matter and disclosure content of the present application also includes combinations of features of the device claims with features of the method claims.The subject matter and disclosure content of the present application also includes sub-combinations of the patent claims in which at least one feature of a patent claim is omitted or replaced by another feature.

[0025] The only figure in the drawing shows a schematic diagram of an embodiment of a channel drying device according to the invention.

[0026] The drawing shows an embodiment of a channel drying device 2 according to the invention for drying hygroscopic material, which is also referred to below as the drying device or device. The basic structure of a channel drying device is generally known to those skilled in the art and will therefore only be explained in detail here to the extent that it is relevant to the explanation of the invention.

[0027] In the illustrated embodiment, the drying device 2 serves to dry material in the form of sawn timber and has a drying chamber 4 for receiving the material to be dried. In accordance with the general structure of a channel drying device, the device 2 has conveying means (not shown in detail in the drawing) for conveying the material to be dried from an inlet 6 to an outlet 8 of the drying chamber in a conveying direction during the drying process. In the drawing, the conveying direction is symbolized by an arrow 10. The structure and function of corresponding conveying means are generally known to those skilled in the art and are therefore not explained in detail here. To simplify the illustration, the conveying means are also not shown in the drawing.

[0028] The drying device 2 further comprises air conditioning means for adjusting a drying climate in the drying chamber 4 during operation of the drying device 2, such that a plurality of climate zones are formed successively in the conveying direction 10, in which different zone climates can be adjusted, are adjusted or are adjusted. The air conditioning means can

[0029] - at least one heating device for heating drying air and / or

[0030] - at least one preferably reversible circulating air fan for circulating the drying air and / or

[0031] - at least one humidification device for humidifying the material to be dried and / or

[0032] - have at least one dehumidification device. The structure and operation of such air conditioning systems are generally known to those skilled in the art and will therefore not be explained in detail here.

[0033] In the illustrated embodiment, six climate zones 12, 14, 16, 18, 20, 22 with different zone climates are set during operation of the drying device 2. The representation of six climate zones is purely exemplary; more or fewer than six climate zones can be provided depending on the respective requirements and conditions. The length of the individual climate zones 12 to 22 in the conveying direction 10 can also be selected within wide limits depending on the respective requirements and conditions.

[0034] According to the invention, the drying device 2 has at least one flow channel which can be connected to at least some of the climate zones via closable flow openings.

[0035] In the illustrated embodiment, the drying device 2 has a first flow channel 24 (internal flow channel) on the supply air side and a second flow channel 26 (external flow channel) on the supply air side.

[0036] In the illustrated embodiment, the drying device 2 further comprises a first flow channel 28 on the exhaust air side (internal flow channel) and a second flow channel 30 on the exhaust air side (external flow channel).

[0037] According to the invention, each flow channel 24 to 30 can be connected to at least some of the climate zones 12 to 20 via closable flow openings, wherein each flow opening is assigned a shut-off device for completely or partially closing the respective flow opening. Each shut-off device is in control connection with the central control device for closing or opening the shut-off device in such a way that, during the drying process, by opening flow openings of the flow channel to adjust the drying climate in at least one climate zone 12 to 20, drying air from at least one climate zone 12 to 20 can be or is introduced into at least one other climate zone 12 to 20.

[0038] Accordingly, during the drying process, by opening flow openings of the flow channel to adjust the drying climate in at least one climate zone 12 to 22, drying air can be introduced from at least one climate zone 12 to 22 into at least one other climate zone 12 to 22. In the illustrated embodiment, each flow channel 24 to 30 is assigned at least one flow opening for each climate zone 12 to 22.

[0039] In the illustrated embodiment, the first flow channel 24 on the supply air side can be brought into flow connection with the climate zones 12 to 22 via flow openings 32, 34, 36, 38, 40, 42, and 44. Purely by way of example, in the illustrated embodiment, two flow openings 40, 42 are assigned to the climate zone 20 (compare zone 5 in the drawing).

[0040] The second flow channel 26 on the supply air side can be brought into flow connection with the climate zones 12 to 22 via flow openings 46, 48, 50, 52, 54, 56.

[0041] The first flow channel 28 on the exhaust air side can be brought into flow connection with the climate zones 12 to 22 via flow openings 58, 60, 62, 64, 66, 68, 70.

[0042] The second flow channel 30 on the exhaust air side can also be brought into flow connection with the climate zones 12 to 22 via flow openings 72, 74, 76, 78, 80, 82.

[0043] Recirculating fans for circulating the air in the drying chamber 4 are designated by reference numeral 84. The recirculating fans 84 are reversible in the illustrated embodiment. The recirculating fans 84 can be controlled so that the same flow direction is established throughout the entire drying chamber 4, i.e., either from top to bottom in the drawing or from bottom to top in the drawing. However, the recirculating fans 84 can also be controlled so that the flow direction changes from one climate zone to the next or, in principle, even within a climate zone.

[0044] Accordingly, in a first flow direction of the air in the drying chamber 4 (in the drawing from top to bottom), the flow openings 32 to 44 and 46 to 56 form supply air openings for introducing supply air from the supply-air-side flow ducts 24, 26 into the drying chamber 4, while after reversing the recirculation fans 84, the flow openings 58 to 70 and 72 to 82 form exhaust air openings for introducing air from the drying chamber 4 into the flow ducts 28, 30.

[0045] The second supply air side flow channel 26 and the second exhaust air side flow channel 30 can be brought into flow connection with the outside air via a flow opening that can be closed by means of a shut-off device, wherein the shut-off devices are in control connection with the central control device.

[0046] Depending on the respective requirements and conditions, the first supply air-side flow duct 24 and the second supply air-side flow duct 26 can be connected to one another by at least one flow opening with an associated shut-off device. Similarly, the first exhaust air-side flow duct 28 and the second exhaust air-side flow duct 30 can also be connected to one another by at least one flow opening with an associated shut-off device.

[0047] In the illustrated embodiment, at least one fan is assigned to each of the flow channels 24 to 30 and arranged in the respective flow channel 24 to 30 to convey drying air along the respective flow channel 24 to 30. The corresponding fans are designated by the reference numerals 86, 88 (supply air-side first flow channel), 90 (supply air-side second flow channel), 92, 94 (exhaust air-side first flow channel), and 96 (exhaust air-side second flow channel). The fans 86 to 96 are also controlled by a central control device during operation of the drying device 2.

[0048] A heating device is provided to heat the drying air in the drying device. The design of such heating devices, for example in the form of one or more heating registers, is generally known to those skilled in the art and will therefore not be explained in detail here. To simplify the illustration, the heating device is also not shown in the drawing.

[0049] As for the structural design, in the illustrated embodiment, the drying chamber has a suspended ceiling above a ceiling and a suspended ceiling below a roof of the drying device, with a gap formed between the ceiling and the suspended ceiling. The flow channels 24 to 30, or at least one of the flow channels 24 to 30, can be arranged or formed in the gap. For this purpose, the flow channels can be inserted into the drying device 2 as separate components or structurally integrated into the drying device.

[0050] To detect the drying climate, particularly air temperature, relative humidity, and air velocity, in climate zones 12 to 22, sensors are provided that communicate with the control device. Such sensors are generally known to those skilled in the art and are therefore not explained in detail here. To simplify the illustration, the sensors are also not shown in the drawing.

[0051] From the preceding description and drawing it can be seen that the flow channels 24 to 30 are designed and run relative to the climate zones in such a way that each of the climate zones 12 to 22 can be brought into flow connection with every other climate zone 12 to 22.

[0052] It is further apparent that the flow channels 24 to 30 are designed such that drying air can be or is guided through the flow channel in the conveying direction or against the conveying direction of the material to be dried.

[0053] The shut-off devices associated with the flow openings of the drying device 2 can, for example, be designed as flaps or slides, and in the illustrated embodiment, are motor-driven between their open position and their blocking position (closed position). The shut-off devices are connected to the control device for control purposes, so that the shut-off devices are moved between their open position and their blocking position under the control of the control device.

[0054] If necessary or desired according to the respective requirements and conditions, separating agents can be provided for at least partial fluidic separation of the climate zones from one another.

[0055] The operation of the drying device 2 according to the invention is as follows:

[0056] During the drying process, hygroscopic drying material in the form of stacked lumber is dried in the drying chamber 4. The individual stacks are conveyed through the inlet 6 into the drying chamber 4 and in the direction of arrow 10 (feed direction), pass through climate zones 12 to 22 during the drying process, and leave the drying chamber 4 through the outlet 8 after completion of the drying process.

[0057] During the drying process, the drying climate in the individual climate zones 12 to 22 is measured by the measuring equipment, particularly with regard to air temperature, relative humidity and air velocity.

[0058] If, for example, it is determined during the drying process that warm and humid air, which is present in Zone 4, for example, is needed in Zone 2, air is directed from Zone 4 to Zone 2 via the first supply air-side flow duct 24. For this purpose, the shut-off device 38 (Zone 4) and the shut-off device 34 (Zone 2) are opened and, with the aid of the fans 88, 86, an air flow is created from the flow opening 38 of Zone 4 through the flow duct 24 to the flow opening 34 of Zone 2. The air thus introduced into Zone 2 causes the drying process to progress in the desired manner. Fresh air can be introduced into climate zones 12 to 22 via the second supply air-side flow duct.

[0059] By simultaneously opening several of the flow openings 32 to 44, air from two or more of the climate zones 12 to 22 can also be mixed in the flow channel 24 and introduced into another climate zone. By adding fresh air via a connection of the first supply-air-side flow channel 24 to an external fresh air supply or by connecting it to the second supply-air-side flow channel, the air mixture's parameters relevant to the drying process, in particular relative humidity, air temperature, and air velocity, can be optimally adapted to the requirements of each climate zone 12 to 22.

[0060] The same applies to the exhaust air side flow channels 28, 30.

[0061] During the drying process, the control device continuously determines the drying air requirements of the individual climate zones, both quantitatively and qualitatively, based on the data from the sensors.

[0062] The fact that, according to the invention, drying air is introduced in almost any manner as needed from at least one of the climate zones 12 to 22 into at least one other of the climate zones 12 to 22 results in a particularly high degree of flexibility in the drying process. This flexibility can be used to optimize the drying process in various ways, for example and in particular to minimize energy consumption or drying time, or with regard to drying quality.

[0063] In addition to the flow channels 24 to 30, the drying device can have a supply channel for supplying warm drying air from at least one climate zone to a loading zone located upstream of the drying device and thus in front of the inlet 6 of the drying chamber 4. The supply channel serves to preheat or preheat the material to be dried stored in the loading zone before being introduced into the drying chamber. This prevents the material to be dried from cooling down in a way that would impair the drying process. Rather, the temperature of the material to be dried upon entering the drying chamber 4 can be selected in a way that positively influences the drying process, particularly at low outside temperatures.

[0064] In a corresponding manner, it is also possible to direct a supply channel for supplying warm drying air from at least one climate zone to an unloading zone arranged downstream of the drying device and thus behind the inlet 6 of the drying chamber in the conveying direction in order to protect the drying material prepared there for collection from frost.

Claims

Claims 1. Channel drying device (2) for drying hygroscopic material, comprising a drying chamber (4) for receiving the material, conveying means for conveying the material from an inlet (6) to an outlet (8) of the drying chamber (4) during the drying process in a conveying direction (10) and with climate control means for adjusting a drying climate in the drying chamber (4) during the operation of the drying device (2), such that a plurality of climate zones (12 to 22) are formed successively in the conveying direction, in which different zone climates can be set, are set or are set, characterized in that the drying device (2) has at least one flow channel (24 to 30) which can be connected to at least some of the climate zones (12 to 22) via closable flow openings (32 to 44; 46 to 56; 58 to 70; 72 to 82), wherein each flow opening (32 to 44; 46 to 56; 58 to 70; 72 to 82) is assigned a shut-off device for completely or partially closing the respective flow opening (32 to 44; 46 to 56; 58 to 70; 72 to 82) and wherein each shut-off device (32 to 44; 46 to 56; 58 to 70; 72 to 82) is in control communication with a central control device which is designed and programmed such that during the drying process, flow openings are opened (32 to 44; 46 to 56; 58 to 70;72 to 82) of the flow channel or channels ( 24 to 30) for adjusting the drying climate in at least one climate zone (12 to 22) drying air from at least one climate zone (12 to 22) can be introduced or is introduced into at least one other climate zone (12 to 22).; 2. Drying device according to claim 1, characterized in that the drying device (2) has a supply air-side first flow channel (24) and an exhaust air-side first flow channel (28).

3. Drying device according to claim 2, characterized in that the drying device (2) has a second air supply channel (26) and a second exhaust air supply channel (30).

4. Drying device according to claim 2 or 3, characterized in that each flow channel (24 to 30) can be connected to at least a part of the climate zones (12 to 22) via closable flow openings (32 to 44; 46 to 56; 58 to 70; 72 to 82), wherein each flow opening (32 to 44; 46 to 56; 58 to 70; 72 to 82) is assigned a shut-off device for completely or partially closing the respective flow opening (32 to 44; 46 to 56; 58 to 70; 72 to 82), wherein each shut-off device is in control communication with the central control device for closing orOpening the respective shut-off device in such a way that during the drying process, by opening flow openings (32 to 44; 46 to 56; 58 to 70; 72 to 82) of the respective flow channel (24 to 30) to adjust the drying climate in at least one climate zone (12 to 22), drying air from at least one climate zone (12 to 22) can be introduced or is introduced.

5. Drying device according to one of the preceding claims, characterized in that at least one flow channel, preferably each flow channel (24 to 30), is assigned a flow opening (32 to 44; 46 to 56; 58 to 70; 72 to 82) to each climate zone (12 to 22).

6. Drying device according to one of claims 2 to 5, characterized in that the second supply air-side flow channel (26) and / or the second exhaust air-side flow channel (30) can be brought into flow connection with a fresh air supply via a flow opening which can be closed by means of a shut-off device, wherein the shut-off device is in control connection with the central control device.

7. Drying device according to one of the preceding claims, characterized in that the drying device (2) has a feed channel for supplying warm drying air from at least one climate zone (12 to 22) to a loading zone upstream of the drying device (2) and / or an unloading zone downstream of the drying device (2), such that drying material stored in the loading zone can be preheated or is preheated before being introduced into the drying chamber (4) and / or drying material stored in the unloading zone (4) can be reheated or is reheated after being removed from the drying chamber.

8. Drying device according to one of the preceding claims, characterized in that at least one fan (86, 88; 90; 92, 94; 96) is assigned to at least one flow channel (12 to 22) and is preferably arranged in the respective flow channel (24 to 30) for conveying drying air along the respective flow channel (24 to 30).

9. Drying device according to one of the preceding claims, characterized in that the air conditioning means - at least one heating device for heating drying air and / or - at least one preferably reversible circulating air fan (84) for circulating the drying air and / or - at least one humidification device for moistening the material being dried and / or - have at least one dehumidification device.

10. Drying device according to claim 9, characterized in that a common heating device is provided for heating the drying air in the drying device (2).

11. Drying device according to one of the preceding claims, wherein the drying chamber (4) has an intermediate ceiling above a ceiling and below a roof of the drying device and an intermediate space is formed between the ceiling and the intermediate ceiling.

12. Drying device according to claim 11, characterized in that at least one flow channel (24 to 30) is arranged or formed in the intermediate space.

13. Drying device according to one of the preceding claims, characterized by sensor means for detecting the drying climate, in particular air temperature, relative humidity and air velocity, in at least one climate zone (12 to 22) and / or at least one flow channel (24 to 30).

14. Drying device according to one of the preceding claims, characterized in that the first supply air-side flow channel (24) and the second supply air-side flow channel (26) can be connected to each other by at least one flow opening with an associated shut-off device and / or that the first exhaust air-side flow channel (28) and the second exhaust air-side flow channel (30) can be connected to each other by at least one flow opening with an associated shut-off device.

15. Drying device according to one of the preceding claims, characterized in that the or each flow channel (24 to 30) is designed and runs relative to the climate zones in such a way that each of the climate zones (12 to 22) can be brought into flow connection with each other climate zone (12 to 22).

16. Drying device according to one of the preceding claims, characterized in that the or each flow channel (24 to 30) is designed such that drying air can be directed or is directed through the flow channel (24 to 30) in the conveying direction or against the conveying direction of the material to be dried.

17. Drying device according to one of the preceding claims, characterized in that at least one shut-off device is designed as a flap or slide, wherein preferably at least one shut-off device is motor-driven to move between its open position and its closed position.

18. Drying device according to one of the preceding claims, characterized by a separating agent for at least partial fluidic separation of the climate zones from each other.

19. Method for drying hygroscopic material using a drying device which - a drying chamber which has a drying area to hold the goods to be dried, - Conveyor for conveying the material to be dried from an inlet to an outlet of the drying chamber in one conveying direction and - Air conditioning means for setting a drying climate in the drying chamber during operation of the drying device, such that a plurality of climate zones are formed successively in the conveying direction, wherein different zone climates can be set, are set, or are established in the climate zones during operation of the drying device, characterized in that a drying device with at least one flow channel is used, which can be connected to at least a part of the climate zones via closable flow openings, wherein each flow opening has a shut-off device for complete or partial closure of the respective flow opening, and that the shut-off devices are controlled during the drying process in such a way that the drying climate in at least one climate zone is adjusted by opening flow openings of the flow channel by introducing drying air from at least one climate zone into at least one other climate zone.

20. Method according to claim 19, characterized in that a drying device according to one of claims 1 to 18 is used.

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