Recovery device

Abstract

The present invention relates to a recovery device and method for recovering heat from particle-laden wet exhaust air, comprising a housing extending from an inlet to an outlet in the flow direction of the particle-laden wet exhaust air, a plurality of tube elements extending parallel to each other within the housing, and a heat exchange medium for absorbing heat from the particle-laden wet exhaust air, in order to provide an device and method that enables long-term continuous operation and energy recovery with little downtime from exhaust of an industrial heat generator, in particular an industrial drying system, in which the wet exhaust air is guided through the inside of the tube elements, the heat exchange medium flows on the outside of the tube elements, and a cleaning unit (14) for cleaning the inside of the tube elements is arranged upstream of the tube elements (10) in the flow direction (SR) of the particle-laden wet exhaust air.

Description

[Technical field]

[0001] The present invention relates to a recovery device and method for industrial heat generators, in particular industrial drying systems, for recovering heat from moist exhaust air containing particles, in particular fibres, for example for laundry. [Background technology]

[0002] Recovery devices and methods are generally known from the state of the art in various designs and are already used experimentally in commercial laundries, for example in industrial drying systems, to recover energy from fibre-laden, moist, in particular water vapour-saturated exhaust air generated during drying of drying materials, in particular fibres.

[0003] In prior art devices and methods, this is done by means of a heat exchanger, in particular a finned heat exchanger. The moist exhaust air passes through the heat exchanger, in particular the outside of the fins, where condensation forms. During drying of the drying material, the exhaust air becomes rich in fibres, which deposit in the heat exchanger, resulting in a significant decrease in the efficiency of heat recovery, a decrease in the functioning of the heat exchanger and ultimately a complete blockage of the heat exchanger.

[0004] A drawback of these prior art devices and related methods is therefore that a permanently low-maintenance or maintenance-free operation is not possible, which therefore not only leads to high maintenance and repair costs but also to frequent operational failures of heat exchangers, for example in the region of the exhaust outlet of industrial or commercial drying systems, leading to malfunctions and interruptions of operation of these systems or, in the worst case, to damage to the drying systems upstream of the recovery devices. Summary of the Invention [Problem to be solved by the invention]

[0005] It is therefore an object of the present invention to provide an apparatus and method that allows for the recovery of energy from wet exhaust air containing particles (particle-laden wet exhaust air) in an industrial heat generator, in particular for an industrial drying system capable of continuous operation for long periods of time. [Means for solving the problem]

[0006] According to the invention, this object is achieved by a recovery device according to claim 1 and by a recovery method according to claim 9. Advantageous further embodiments of the invention are set out in the dependent claims.

[0007] The recovery device for recovering heat from the particle-laden wet exhaust gas according to the present invention comprises a housing extending in a flow direction of the particle-laden wet exhaust gas from an inlet to an outlet, a plurality of tube elements extending in the housing, preferably parallel to a longitudinal axis of the housing and / or parallel to each other, and a heat exchange medium for absorbing heat from the particle-laden wet exhaust gas, where the particle-laden wet exhaust gas is guided through the inside of the tube elements and the heat exchange medium flows outside the tube elements.Furthermore, according to the present invention, a cleaning unit arranged upstream of the tube elements in the flow direction of the particle-laden wet exhaust gas is provided for cleaning the inside of the tube elements.

[0008] The inventors have realised that locating a washing unit upstream of the tube elements has many advantages, in particular that it allows to recover the energy of the wet and warm exhaust air of industrial heat generators, in particular industrial drying systems of commercial laundries, whereby the accumulation of particles, in particular fibres, in the tube elements is significantly reduced by the additional cleaning by the washing unit, and thus the risk of malfunction or failure of the collection device due to particle accumulation can be significantly reduced, which directly translates into longer uninterrupted operating times, cost savings and a significant reduction in maintenance work.

[0009] The inventors have also realised that a heat exchanger configured as a tube bundle heat exchanger allows for a particularly efficient energy recovery from the particle-laden wet exhaust air, in particular that such a tube bundle heat exchanger, in which the particle-laden wet exhaust air is guided into tubes, allows for effective cleaning by the cleaning unit according to the invention, whereas for example finned heat exchangers in connection with particle-laden exhaust air are almost impossible to keep sufficiently clean and passable over a long period of time.

[0010] A recovery device is generally understood to be a structural unit that is provided for recovering supplied substances and / or resources. Preferably, the recovery device recovers at least one substance and / or one resource from a mixture of different substances and / or resources. An example of a recovered substance is in particular water as a condensate from wet exhaust air or other wet gases or gas mixtures. The recovered resource may be heat only or may also be other resources. Preferably, the recovery device is primarily intended for heat recovery, particularly preferably condensed water is also recovered.

[0011] In principle, the recovery device can be located at any place and at any distance from the industrial heat generator or the industrial drying system. For example, the recovery device can be located on a working surface formed by a wall, ceiling or roof of a building, etc. For this purpose, the housing can have, for example, support elements for fixing it to the surface to be used. Preferably, the recovery device is located directly on the roof and / or in the area of ​​the outlet of the industrial heat generator or the industrial drying system. For example, holding elements for transporting and / or handling the recovery device are provided on the housing.

[0012] An industrial heat generator is any system that generates heat and releases at least some of the heat as part of a gas stream, in particular an exhaust air stream. Examples of such industrial heat generators are drying systems and ovens, for example industrial baking ovens and ovens in the food industry. However, heat generators can also be used in other industrial sectors, such as textile production and processing. What all industrial heat generators have in common, however, is that they release an exhaust air stream that contains particles and moisture, preferably water vapor or high humidity.

[0013] The industrial drying system in which the recovery device is preferably used is in principle any system for removing water, aqueous solutions and / or cleaning agents from objects, the drying system being preferably for drying textile products, particularly preferably for drying laundry. In this context, the drying system is particularly preferably part of a laundry and very particularly preferably arranged in one or more industrial washer-dryers. It can also be used in combination with larger drying devices such as those used in hotels. In this context, an industrial drying system is understood to be a system intended for use in commercial, professional and / or industrial areas for drying wet items, in particular wet textile products and / or wet laundry.

[0014] According to the invention, the exhaust air fed to the recovery device contains particles, which may be any solid contained in the exhaust air. Preferably, the particles are smaller than 5 mm and / or have a mass of less than 1 g. For example, the particles may be formed from baked goods and / or flour pieces. In principle, however, particles made of any material are conceivable, but preferably hydrophilic. It is also preferred that at least a part of the particles are fibrous, it is particularly preferred that the particles are mainly fibrous, and it is very particularly preferred that the particles are essentially exclusively fibrous. Here, fibers are generally understood to mean any particles that are generated from or can be separated from fibers during the processing of textiles (textile products) and laundry, in particular during washing, smoothing and / or drying. Furthermore, the exhaust air may also contain other particles, such as foreign bodies or components of cleaning agents or other auxiliary materials introduced with the textiles.

[0015] The exhaust air is described as wet because in addition to particles, the exhaust air contains a certain amount of liquid. This can be any liquid, preferably the liquid in the exhaust air is completely present as a gas or vaporized. Particularly preferably, the water contained in the exhaust air is a vaporized aqueous solution, particularly preferably essentially pure water, with small amounts of other substances, such as ingredients of detergents or fabric softeners, inevitably present.

[0016] The housing is used to guide the moist exhaust air from the inlet to the outlet and / or to seal the interior of the recovery device from the environment and / or to prevent the supplied exhaust air from being released in an uncontrolled manner. For this purpose, the housing is preferably tubular. The housing preferably has a polygonal, elliptical or, particularly preferably, circular cross section and extends along the longitudinal axis of the housing between the inlet and the outlet.

[0017] Each of the tube elements is arranged in the flow direction of the particle-containing wet exhaust air between the inlet and the outlet of the housing. Furthermore, the tube elements preferably have a polygonal, elliptical or particularly preferably circular cross section and extend along the longitudinal axis of the tube element. The diameter of the tube element, especially in the region of the tube element, is preferably at most 50%, particularly preferably at most 25%, especially preferably at most 15%, particularly preferably at most 10% of the diameter of the housing.

[0018] The recovery device is preferably designed to allow at least 1000 l / h of exhaust gas flow to pass through. In general, the recovery device is preferably designed and specifically dimensioned so that the pressure in the inlet area does not increase significantly compared to the ambient pressure. This is because industrial heat generators, especially industrial drying systems, are usually not designed to increase pressure and need to generate the maximum possible volumetric flow rate, so that back pressure in the recovery device area would interfere with the operation of the heat generator or drying system. Therefore, the recovery device is preferably designed to allow at least 7000 l / h, particularly preferably at least 8000 l / h, very particularly preferably at least 9000 l / h of exhaust gas flow to pass through.

[0019] The longitudinal axis of the tube element can be arranged, for example, parallel to or at the longitudinal axis of the housing. Furthermore, the tube element is formed such that the particle-containing wet exhaust air flows through the tube element in the direction of the outlet of the housing. For example, the tube element is formed as a tube (pipe) having a constant diameter. Preferably, the housing and / or the tube element are formed of a metallic material, in particular a steel or aluminum material.

[0020] The heat exchange medium essentially serves to absorb heat from the moist exhaust air and / or dissipate the absorbed heat from the recovery device, in particular to another heat exchanger. For this purpose, the heat exchange medium preferably has a lower temperature than the particle-containing moist exhaust air, at least when it is fed to the recovery device. This allows the heat from the exhaust air to be transferred to the heat exchange medium by temperature difference and / or by convection. In principle, it is conceivable to continuously feed the recovery device with fresh heat exchange medium, but it is preferred to circulate the heat exchange medium, in particular in a closed circuit, for example when used for directly heating water, in particular washing water.

[0021] Preferably, the recovery device, in particular the housing and the tube elements, are formed in such a way that the heat exchange medium at least partially, preferably completely, surrounds the tube elements in the circumferential direction, in particular flows around them. The heat exchange medium is formed as a fluid that flows around the tube elements, for example pure water, an aqueous solution, a water-glycol mixture or salt water. For this purpose, the housing can have an inlet and an outlet, which are preferably arranged outside the recovery device through the housing.

[0022] During operation of the recovery device, the particle-containing wet exhaust air is introduced into the housing through the inlet, flows through or passes through the washing unit in the flow direction, passes through one of the tube elements and is discharged from the housing via the outlet. The wet exhaust air has, for example, a residual moisture content of 30% to 50% and a temperature of 100°C to 140°C. Furthermore, the wet exhaust air contains fibers due to the upstream drying of drying materials such as clothes, which is preferably performed in an industrial dryer. Due to the heat transfer from the wet exhaust air to the heat exchange medium, the temperature of the exhaust air is reduced and at least a part of the moisture in the exhaust air is condensed in the tube element. This forms a condensate in the tube element and at least a part of the fibers are separated from the exhaust air or the fibers are attached to the tube element. The condensate containing the fibers can be discharged from the housing actively, for example by using a conveyor unit, or passively, for example by using an incline. The discharged condensate containing the fibers is discharged or collected, for example by using a collection unit, for example a gutter or a drain, located at the level at which the recovery device is used and / or below, and is then returned to the building for reuse.

[0023] As the drying process of the exhaust air proceeds, already dried fibres accumulate in the tube elements and / or the amount of condensate is not sufficient to completely remove the accumulated fibres from the tube elements. The cleaning unit is designed to remove the preferably already dried fibres accumulated in the tube elements. The cleaning unit is preferably arranged in the direction of the flow of the wet exhaust air between the inlet of the housing and the tube elements in the housing. Furthermore, the cleaning unit can be designed to release a fluid medium, such as compressed air or water, into the housing. The housing can also be provided with a maintenance opening, which is preferably arranged in the area of ​​the cleaning unit, so that in the very unlikely event of a breakdown or maintenance, the cleaning unit can be quickly and easily accessed.

[0024] The cleaning unit preferably has at least one discharge port for discharging a fluid medium, in particular compressed air or water. The discharge port can generally be arranged at a fixed position and is preferably aligned in the flow direction of the wet exhaust air. According to an advantageous further development of the invention, however, the cleaning unit has at least one discharge port rotatable about the longitudinal axis of the housing for discharging a fluid medium, in particular compressed air or water, so that the tube elements can be particularly reliably cleaned.

[0025] Discharge ports are generally understood to be openings of the cleaning unit through which the fluid medium can be discharged. The discharge ports may be formed in such a way that the fluid medium is injected into the wet fiber-containing exhaust air. Furthermore, the discharge ports may have an outwardly increasing diameter and / or be conical. Furthermore, the discharge ports are particularly preferably formed as nozzles, through which the fluid medium is discharged under pressure, in particular under a pressure of 1 to 8 bar, preferably 2 to 6 bar, particularly preferably 2 to 5 bar, into the wet fiber-containing exhaust air and / or is directed towards the tube element. The nozzles or discharge ports may also be formed as slots in the surface of the cleaning unit. The rotation of the discharge port about the longitudinal axis of the housing is understood to mean, in particular, a movement along a path of movement at a constant distance from the longitudinal axis of the housing and / or along a circular path around the longitudinal axis. Preferably, the movement path runs in a movement plane arranged perpendicular to the longitudinal axis of the housing. In principle, however, the movement path can be formed in any way, such as elliptical.

[0026] It is particularly preferred that the cleaning unit has at least two discharge ports, each of which is arranged on the discharge element. Alternatively, it is preferred that a single discharge element has a plurality of discharge ports distributed on its surface. The discharge element is essentially formed for the arrangement and / or alignment of the discharge ports and / or for the supply of the fluid medium to the discharge ports. Each discharge element preferably has at least one discharge port, particularly preferably exactly one discharge port, which is particularly preferably arranged in the region of one end of the discharge element. Alternatively, the discharge element can also have a plurality of discharge ports, which are then particularly preferably arranged at the same distance from one another and / or evenly distributed around the discharge element. The plurality of discharge elements is preferably tubular and / or unbranched. Particularly preferably, the discharge element has at least one curved surface. Furthermore, the plurality of discharge elements can be connected to one another in an integral manner. Also, it is preferred that the plurality of discharge elements of all discharge ports are formed identically to one another and / or are arranged rotationally symmetrically. Particularly preferred are also designs of the emission element with an outwardly curved and / or elliptical or hemispherical surface, in which the emission ports are arranged, in particular in the form of a plurality of slots. Such emission ports formed as slots can extend anywhere on the surface of the emission element, for example radially and / or helically relative to the axis of rotation of the emission element.

[0027] The cleaning unit may comprise an active drive unit, such as an electric motor, for rotating the discharge port, in particular the discharge element, about the longitudinal axis of the housing. However, preferably, the discharge element is formed with one or more discharge ports and / or the discharge ports are aligned such that it rotates about the longitudinal axis of the housing without a driving force, in particular by the pressure of the emerging fluid medium. For this purpose, the discharge ports are preferably arranged at an angle (slanted) to the direction of the movement path and / or formed in a curved extension on its surface.

[0028] According to an advantageous embodiment of the invention, at least one discharge element is arranged on a connection element of the cleaning unit arranged parallel to or preferably on the longitudinal axis of the housing, the discharge element and / or the connection element being mounted rotatably around the longitudinal axis of the housing. The connection element is used to direct the fluid medium to the discharge element. Furthermore, the connection element preferably has a cylindrical and / or circular cross section. The fluid medium is preferably supplied to the recovery device via a pipe element arranged on the connection element, which can be connected to a pump unit, for example arranged outside the housing and / or on the housing and / or inside the building in which the recovery device is arranged. Furthermore, the pipe element is preferably arranged in the housing, sealed, for example by means of a sealing element or a welded seam. Particularly preferably, the connection element and / or the pipe element have a bearing element, for example a sliding bearing or a roller bearing for rotatably mounting the discharge element and / or the connection element.

[0029] According to an advantageous further development of the invention, a plurality of tube elements, preferably identical to one another, forming a tube bundle heat exchanger are arranged parallel to one another in a housing, each tube element having an inlet opening at one end for feeding the particle-containing wet exhaust air and preferably an outlet opening for discharging the exhaust air. Moreover, all inlet openings are preferably arranged in a common plane. Even more preferably, all inlet openings of the plurality of tube elements are arranged equidistant from the inlet of the housing and / or all outlet openings are arranged equidistant from the outlet of the housing. Also, preferably, the cross-sectional area of ​​all tube elements is at least 25%, particularly preferably at least 50%, very particularly preferably at least 75% of the cross-sectional area of ​​the housing, so that the exhaust air can pass through the tube elements well and / or undesirable pressure build-up in the recovery device is avoided. The tube bundle heat exchanger preferably has a length of at least 50%, particularly preferably at least 60%, most preferably at least 70% of the length of the housing in the direction of the longitudinal axis of the housing. The housing preferably has a larger diameter in the region of the tube bundle heat exchanger than at the inlet, so that the diameter of the housing particularly preferably increases steadily in the region of the washing unit.

[0030] The tube elements preferably extend between two sealing elements arranged in the housing for separating the wet exhaust air from the heat exchange medium, so that the particle-containing wet exhaust air flows only through the tube elements and the heat exchange medium flows completely around the outside of the tube elements. The inlet and / or outlet openings of the tube elements are preferably arranged on the sealing elements. Particularly preferably, the tube elements are respectively connected to the sealing elements, for example by welding. The sealing elements are preferably plate-shaped. The sealing elements are also preferably arranged perpendicularly to the longitudinal axis of the housing. Particularly preferably, the diameter of the sealing elements is adapted to the housing, in particular to the inner diameter of the housing, so that the sealing elements and the tube elements preferably arranged between the sealing elements can be inserted into the housing during the manufacture of the recovery device. To seal the sealing elements against the housing, the sealing elements are for example welded to the housing. The sealing elements are also preferably made of a metallic material. The inlet and outlet of the housing are each arranged in an area of ​​one of the sealing elements such that the heat exchange medium flows around preferably all of the tube elements, particularly preferably crosswise to the flow direction of the wet exhaust air between the sealing elements, such that when the wet exhaust air flows through the tube elements and the heat exchange medium flows over the tube elements, there is no contact between the particle-laden wet exhaust air and the heat exchange medium.

[0031] According to an advantageous embodiment of the invention, at least one discharge port of the cleaning unit is oriented (aligned) and / or movable in such a way that the fluid medium flows towards the area of ​​the inlet openings of the tube elements and impinges (impacts) at least 40%, preferably 60%, particularly preferably 80%, of the total area of ​​all inlet openings. The discharge port is preferably aligned in such a way that the fluid medium is discharged in the flow direction of the moist fiber-containing exhaust gas, for example parallel to the longitudinal axis of the housing and / or at an angle of less than 90°, particularly preferably less than 45°, most preferably less than 15°. This advantageous embodiment of the invention allows a particularly reliable cleaning of multiple tube elements of a tube bundle heat exchanger, and even with an increased throughput, the risk of failure or malfunction of the recovery device is significantly reduced.

[0032] According to a particularly advantageous further development of the invention, the recovery device has a control unit connected to at least one sensor element, in particular for controlling at least the cleaning unit. The control unit is preferably formed in the form of a programmable unit, for example a computer, a PLC or an external and / or higher level control system. Preferably, the recovery device has at least one, particularly preferably several, sensor elements for detecting sensor signals such as the temperature and / or pressure and / or moisture content of the moist exhaust air. The sensor element or sensor elements are connected to the control unit for transferring the detected data. The sensor elements are arranged, for example, in front of and / or behind the tube element or, more preferably, in the region of the tube element on the housing. The control unit is preferably connected to at least one control means for activating and deactivating the cleaning unit. Preferably, the control unit is formed to execute a predeterminable program as a function of the sensor signal. The predeterminable program preferably has a setting option for predeterminable limit values ​​(limit values) as described below. Furthermore, the control unit is formed to transfer the detected data to a receiver, which is particularly preferably arranged remotely from the recovery device.

[0033] The inventive method for recovering heat from particle-laden wet exhaust air for industrial heat generators, in particular for industrial drying systems, can in particular be carried out with the above-mentioned recovery device and comprises as process steps: feeding wet exhaust air containing particles, in particular fibers, to a number of tube elements via an inlet of the recovery device, heat exchange between the wet exhaust air and a heat exchange medium that thermoregulates and / or flows around the tube elements, and at least temporarily cleaning the tube elements by a cleaning unit of the recovery device to remove accumulated particles and / or fibers and / or keep the tube elements free of particles and / or fibers. Preferably, the dry exhaust air, at least partially separated from the particles or fibers, is discharged via an outlet of the housing, for example to the outside environment.

[0034] In principle, the tube elements can be cleaned in any way, at any time and for any period of time. However, preferably, the cleaning is controlled periodically and / or as a function of predefined limit values ​​and / or after a fixed period of time and / or after a fixed time interval. Particularly preferably, the moisture content and / or the temperature of the exhaust air are set as predefined limit values. The moisture content and the temperature of the exhaust air are preferably detected by the above-mentioned sensor elements and, particularly preferably, are monitored continuously. One and / or two different predefined limit values ​​can be provided for the moisture content and the temperature of the exhaust air. The cleaning unit is activated, for example, when the moisture content of the exhaust air falls below a first limit value and / or when the temperature of the exhaust air exceeds a second limit value, since if the moisture content falls below a certain level, self-cleaning becomes impossible due to condensed water during the fiber drying process. The end phase of the drying process can also be recognized by an increase in temperature, which is a good time to clean the recovery device before using it again.

[0035] It is particularly preferred to recover heat from the moist exhaust air without first washing the tube elements, and as the drying process progresses and the moisture content of the exhaust air is reduced, washing is turned on to remove the already dried fibres from the tube elements by the fluid medium flowing through each tube element.

[0036] Two embodiments of the recovery device according to the invention and the recovery method according to the invention are explained in more detail below with reference to the drawings. [Brief description of the drawings]

[0037] [Figure 1] FIG. [Figure 2a] 2 is a schematic vertical cross-sectional view taken along line AA of the recovery device shown in FIG. 1. [Figure 2b] FIG. 2B is a schematic cross-sectional view of the recovery device shown in FIG. 1 and FIG. 2A taken along line BB. [Diagram 3] FIG. 2 is a schematic longitudinal section through a second embodiment of a recovery device with a modified washing unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] Fig. 1 shows an exemplary embodiment of a recovery device 1 with a housing 2. The housing 2 has two support elements 3 for fixing the housing 2 to a roof and two holding elements 4 for transporting the housing 2. Furthermore, the housing 2 has an inlet 5 for feeding the moist exhaust air containing fibers and an outlet 6 for removing the exhaust air. Furthermore, the housing 2 has a circular cross section QG with a diameter DG, which extends along the longitudinal axis L of the housing 2 between the inlet 5 and the outlet 6.

[0039] The housing 2 is provided with an inlet 7 and an outlet 8 for passing a heat exchange medium in the form of a mixture of water and glycol.

[0040] As shown in FIG. 2a, a plurality of tube elements 10 forming a tube bundle heat exchanger 9 are arranged parallel to each other in the housing 2. The plurality of tube elements 10 are identical to each other and are formed as tubes having a constant diameter DR. Each tube element 10 has an inlet opening 11 and an outlet opening 12. The plurality of tube elements 10 are arranged between two sealing elements 13 spaced apart from each other along a longitudinal axis L of the housing. The inlet opening 11 and the outlet opening 12 are respectively arranged on the sealing elements 13 in a common plane formed by the sealing elements 13. Furthermore, the inlet opening 11 and the outlet opening 12 are respectively arranged equidistantly from the inlet 5 and from the outlet 6. The sealing elements 13 separate the heat exchange medium from the humid exhaust air containing fibers. The housing 2, the sealing elements 13 and the tube elements 10 are made of steel.

[0041] Inside the housing 2, a cleaning unit 14 is arranged in front of the tube element 10, with two discharge ports 16 respectively arranged in a discharge element 15. The discharge elements 15 are integrally connected to one another and are rotatably mounted in a connecting element 17 in a bearing element 18 about the longitudinal axis L of the housing 2. A fluid medium in the form of compressed air is supplied to the discharge elements 15 and to the discharge ports 16 via a pipe element 19 connected to the connecting element 17. Furthermore, a maintenance opening 22 is arranged in the housing 2 in the region of the cleaning unit 14.

[0042] In an alternative embodiment not shown, the cleaning unit 14 may have multiple discharge ports 16 spaced at a distance from each other along the discharge element 15 .

[0043] 1 further comprises a control unit 20 and a number of sensor elements 21 connected to the control unit 20 for detecting, for example, the moisture content or the temperature of the exhaust gas. The sensor elements 21 are arranged in a housing 2 (see FIG. 2a).

[0044] The recovery device 1 can be used to carry out the recovery method. The recovery device 1 is connected, for example, to an industrial drying system for drying wet textile products and laundry. For this purpose, the recovery device 1 is designed to pass a volume flow rate of 9000 l / h. The wet fiber-containing exhaust air discharged from the drying system is fed to the recovery device 1 via the inlet 5 of the housing 2. The fiber-containing wet exhaust air flows from the inlet 5 in a flow direction SR, passes through a washing unit 14 and enters through the inlet opening 11 into the tube element 10. The heat exchange medium flowing from the inlet 7 to the outlet 8 flows continuously around the tube element 10. In the tube bundle heat exchanger 9, heat exchange takes place between the fiber-containing wet exhaust air and the heat exchange medium. The latter has a lower temperature than the fiber-containing wet exhaust air, so that there is a temperature gradient in the direction of the heat exchange medium. Due to the heat exchange, the temperature of the fiber-containing wet exhaust air is reduced and condensate is formed in the tube element 10. The condensed water flows out of the outlet 6 of the housing 2 together with the fibers and is used to remove some of the fibers contained in the exhaust air from the housing 2. The dry exhaust air, which is almost free of fibers, is discharged into the environment through the outlet 6 of the housing 2.

[0045] The sensor element 21 continuously detects the temperature and the moisture content of the moist exhaust air and transmits the obtained data to the control unit 20. As the drying process proceeds, the moisture content of the exhaust air decreases. When the moisture content falls below a limit value, which can be preset in the control unit 20, the control unit 20 switches on the cleaning unit 14. The discharge element 15 rotates about the longitudinal axis L of the housing 2 by the compressed air exiting from the discharge port 16. The discharge port 16 is aligned in the direction of the inlet openings 11 of the tube elements 10, so that compressed air is introduced into all the tube elements 10 in conjunction with the rotation of the discharge element 15. The compressed air flows through the tube elements 10 and removes the already dried and deposited fibers in the tube elements 10. Furthermore, the compressed air promotes the transport of the condensate together with the fibers in the direction of the outlet 6 of the housing 2.

[0046] The recovery device 1 allows the energy of the moist warm exhaust air from industrial drying systems to be recovered for commercial laundries. By recovering the heat from the exhaust air and reusing the condensate in the laundry if necessary, for example up to about 120 kW / h of energy can be recovered. By arranging a washing unit 14 upstream of the tube bundle heat exchanger 9 to remove fibres deposited on the tube elements 10, the risk of malfunctions and failures of the recovery device 1 can be significantly reduced.

[0047] A second embodiment of the recovery device 1, shown in Fig. 3, differs only in the design of the cleaning unit 14. Here, the discharge element 15, which is rotatably arranged on the pipe element 19 by means of the bearing element 18, is formed as an outwardly curved surface or as a part of a sphere, and the discharge ports 16 are formed on this curved surface as slot-shaped nozzles. During operation of the cleaning unit 14, the fluid medium for cleaning (water in this case, compressed air is also conceivable) is introduced under pressure into the interior of the discharge element 15 and discharged from the discharge ports 15 on the surface in the direction of the inlet opening 11 of the tube element 10. Due to the radially curved path of the discharge ports 16 formed as slot-shaped nozzles, the discharge element 15 rotates automatically. It is also preferably made of stainless steel and / or the discharge ports 16 are uniformly arranged on the surface of the discharge element 15, in particular with respect to the axis of rotation. [Explanation of symbols]

[0048] 1 Recovery device 2. Housing 3 Supporting elements 4 Retention elements 5 entrance 6 exit 7 Intake 8. Removal port 9 Tube bundle heat exchanger 10 Tube Elements 11 Inlet opening 12 Outlet opening 13 Sealing element 14 Cleaning unit 15 Emission elements 16 Discharge Port 17 Connection elements 18 Bearing elements 19 Pipe Elements 20 Control Unit 21 Sensor elements 22 Maintenance opening L Longitudinal axis of housing DG Housing Diameter DR Tube element diameter QG housing cross section SR Exhaust flow direction

Claims

1. 1. A recovery device for recovering heat from particle-laden wet exhaust air of an industrial heat generator, in particular an industrial drying system, comprising: a housing (2) extending in a flow direction (SR) of the particle-laden wet exhaust gas from an inlet (5) to an outlet (6); a plurality of tube elements (10) extending parallel to one another within the housing (2); a heat exchange medium that absorbs heat from the particle-laden wet exhaust gas; the particle-laden wet exhaust gas is directed through the inside of the tube element, and the heat exchange medium flows outside the tube element; a cleaning unit (14) for cleaning the inside of the tube element is arranged upstream of the tube element (10) in the flow direction (SR) of the particle-laden wet exhaust gas; A recovery device characterized by:

2. The cleaning unit (14) has at least one discharge port (16) rotatable about the longitudinal axis (L) of the housing (2) for discharging a fluid medium.

2. The recovery device according to claim 1.

3. The cleaning unit (14) includes at least two discharge ports (16) arranged on the outwardly curved surface of the discharge element (15).

2. The recovery device according to claim 1.

4. the at least one discharge element (15) is arranged on a connecting element (17) of the cleaning unit (14) arranged parallel to or on the longitudinal axis (L) of the housing (2); the at least one emitting element (15) and / or the connecting element (17) are mounted rotatably about the longitudinal axis (L) of the housing (2); 4. The recovery device according to claim 3.

5. A plurality of tube elements (10) identical to one another and forming a tube bundle heat exchanger (9) are arranged parallel to one another in the housing (2), each of the tube elements (10) having an inlet opening (11) at one end for supplying particle-laden wet exhaust air, all of the inlet openings (11) being arranged in one plane.

2. The recovery device according to claim 1.

6. at least one discharge port (16) of the cleaning unit (14) is oriented and / or movable in such a way that the fluid medium is directed towards the area of ​​the inlet openings (11) of the tube element (10) and impinges on it in a proportion of at least 40%, preferably at least 60%, particularly preferably at least 80% of the total area of ​​all inlet openings (11); 3. The recovery device according to claim 2.

7. The tube element (10) extends between two sealing elements (13) arranged in the housing (2) to separate the particle-laden wet exhaust air from the heat exchange medium, and the particle-laden wet exhaust air flows only through the tube element (10), while the heat exchange medium flows completely around the outside of the tube element (10).

6. The recovery device according to claim 5.

8. a control unit (20) connected to at least one sensor element (21) for at least controlling said washing unit (14), 8. A recovery device according to claim 1, wherein the recovery device is a device for recovering waste.

9. A method for recovering heat from particle-laden wet exhaust air in an industrial heat generator, in particular an industrial drying system, using a recovery device as claimed in claim 5, comprising: supplying particle-laden wet exhaust air through an inlet (5) to a plurality of tube elements (10) of said recovery device (1); exchanging heat between the particle-laden wet exhaust air and a heat exchange medium that is conditioned and / or flows around the tube element (10); and at least temporarily cleaning the inside of the tube element (10) to remove accumulated particles using a cleaning unit (14) of the recovery device (1). A recovery method characterized by:

10. The cleaning of the tube element (10) is controlled periodically and / or as a function of predefinable limit values; The recovery method according to claim 9 .

11. the moisture content and / or temperature of the particle-laden wet exhaust gas is set to a predeterminable limit value; The recovery method according to claim 9 .

12. initially recovering heat from the particle-laden wet exhaust gas without washing the tube elements (10), and as the drying process progresses and the moisture content of the particle-laden wet exhaust gas decreases as a result, washing is turned on to remove already dried particles from the tube elements (10) by a fluid medium flowing through each of the tube elements (10); The recovery method according to claim 9 .

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