A VENTILATION ARRANGEMENT FOR A TUMBLE DRYER

Abstract

 Disclosed herein is a tumble dryer (100) comprising: a housing (110); a rotatable drum (120) arranged in the housing (110); a first fan (130) arranged to generate a flow of process air passing through the rotatable drum (120); a heat pump arrangement (140) arranged in the flow of process air; wherein the heat pump arrangement (140) is configured to heat and dry the process air; and a ventilation arrangement (150) arranged in a wall (111) of the housing (110) and configured to draw air from within the housing (110) to an outside (200) of the housing (110);
wherein the ventilation arrangement (150) comprises a second fan (160) arranged to generate a second flow of air passing through the ventilation arrangement (150) to the outside of the housing (200); and wherein the flow of process air and the second flow of air are separate from each other.

Description

Technical Field

[0001] The present invention relates to the technical field of tumble dryers, and in particular to a ventilation arrangement for a tumble dryer.

Background

[0002] Tumble dryers play an important role in today's laundry industry, both in professional environments such as hotels, hospitals, or laundromats, as well as in domestic environments such as people's homes. There is a range of different types of tumble dryers, whereof exhaust tumble dryers and heat pump tumble dryers are some of the most common ones. In the first one, ambient air is drawn into the appliance, where it is heated up before it passes through the rotating drum to absorb water from the moist textiles, before the now humid air is blown out through an exhaust. In the second type the process air circulates in a closed loop where a heat pump dehumidifies and heats the process air before it passes through the rotating drum to absorb water from the moist textiles, before it returns to the heat pump. The heat pump dryers are more energy efficient than the exhaust dryers, and conserve a majority of the heat within the tumble dryer instead of exhausting it to the surrounding environment.

[0003] Even if the process air in a heat pump tumble dryer circulates in a closed loop, some degree of leakage of the process air will always occur. The leakage may for example occur around the sealing of the rotating drum or in junctures between different parts of the process air channel. Leakage may also occur or increase after a service by a technician if the components are not properly re-installed. If the process air leaks between the rotating drum and the heat pump it is both warm and humid after contact with the moist textiles inside the drum.

[0004] Normally, the leaked process air can escape the tumble dryer housing through openings in the housing. In most cases, natural convection is enough to ventilate this leaked air out of the housing without it causing any problems. Also in an exhaust tumble dryer leakage of process air may occur, but as new process air is continuously drawn usually from the inside of the housing, there is a good ventilation and the leakage does not result in any problems here either.

[0005] However, if a high concentration of leaked process air builds up inside the housing of a heat pump dryer, vapour from the humid air may condensate on colder surfaces, such as on components or the inner walls of the housing outside the drum. This creates multiple problems, as condensate on a display might negatively impact the readability and user experience and condensate on electrical components may lead to a short circuit. Further, condensate on metal surfaces may cause corrosion. Therefore unwanted condensate inside the machine may ultimately lead to malfunction of the tumble dryer.

Summary

[0006] In the light of the above, it is desired to provide alternative solutions for tumble dryers in order to overcome the problem of hot, humid air getting trapped inside the housing of the tumble dryer. This and other objectives are achieved by providing a tumble dryer having the features in the independent claims. Preferred embodiments are defined in the dependent claims.

[0007] Therefore, according to a first aspect of the present invention, there is provided a tumble dryer, comprising a housing, a rotatable drum arranged in the housing, a first fan arranged to generate a flow of process air passing through the drum, a heat pump arrangement arranged in the flow of process air, wherein the heat pump arrangement is configured to heat and dry the process air. The tumble dryer further comprises a ventilation arrangement arranged in a wall of the housing and configured to draw air from within the housing to an outside of the housing. The ventilation arrangement comprises a second fan arranged to generate a second flow of air passing through the ventilation arrangement to the outside of the housing, and wherein the flow of process air and the second flow of air are separate from each other.

[0008] By providing a tumble dryer having the features above, it is possible to efficiently ventilate air trapped inside the housing of the tumble dryer to an outside of the tumble dryer, i.e., a surrounding environment. By ventilating trapped air from the tumble dryer, the amount of warm and humid air inside the housing is advantageously decreased. Thereby, the formation of condensate on surfaces inside the housing is prevented, decreasing the risk of corrosion, short-circuits of electronic components and overall malfunction of the tumble dryer.

[0009] As mentioned above, the tumble dryer comprises a heat pump arrangement for drying the flow of process air before it enters the drum. According to an example, the heat pump arrangement comprises a compressor, a condenser, an evaporator, and at least one expansion device. The heat pump arrangement is arranged in the flow of process air, meaning that the flow of process air may flow through the heat pump arrangement. The flow of process air may be heated by the condenser such that its relative humidity is decreased, thereby increasing its capacity to absorb water vapour from the laundry, the heated process air may thereafter enter the rotatable drum and dry wet laundry placed therein. The flow of process air may then leave the drum as hot, humid air, and flow back to the heat pump arrangement where it is cooled and dehumidified by the evaporator. The cold and dry flow of process air may then flow past the compressor where it is preheated, before passing through the condenser again where it is heated, and then flow back into the drum again. The expansion device may be positioned between the condenser and the evaporator in order to induce a pressure drop in the refrigerant circulating through the heat pump. The flow of process air may therefore be a closed-loop air flow.

[0010] By "closed-loop air flow" may herein be meant that the same air is circulated between the different components in cycles, where it is heated, humidified, cooled, dried, and heated again, without continuously introducing new air into the loop from the surrounding environment. The process air is thus reused within the closed air loop.

[0011] Therefore, according to an exemplifying embodiment of the present disclosure, the flow of process air is a closed loop passing the heat pump arrangement, the rotating drum, and the first fan. The flow of process air is circulated in the loop by the first fan. The first fan may be an electrical fan or a mechanical fan, for example. Further, the first fan may be an axial fan, a propeller fan, or a radial fan. It will be appreciated that other types of fans are also possible. The first fan may be arranged in the flow of process air, for example downstream the rotating drum and upstream the heat pump arrangement in the direction of the flow.

[0012] Moreover, the housing of the tumble dryer may house further components. For example, the housing may house different electronic components, such as lamp units, control units, motor units, etc. The lamp units may for example illuminate the inside of the rotating drum, or illuminate a user display arranged in a front side of the tumble dryer. The control units may control the user display, the operation of the tumble dryer, etc. The motor unit(s) may for example be arranged for driving the rotating drum. There may also be other types of components inside the housing, for example a lint filter, partition walls, components for the door, etc. Many of these previously mentioned components may be sensitive to water or other liquids, for example due to their material or electrical characteristics. The water or liquid may cause a short-circuit in electrical components or corrosion of material during continuous exposure to water or liquid. Since the operation of a tumble dryer involves drying wet laundry, the flow of process air includes large volumes of both hot and humid air being circulated inside the housing of the tumble dryer. Even in the case of a closed loop flow of process air, hot and humid air is a fugitive gas that easily escapes through narrow spaces, such as junctures, rotary sealings or cracks in ducts, for example. The hot and humid air may therefore escape from the closed loop and spread within the housing. The components and inner surfaces of the housing typically have a lower temperature than that of the hot and humid process air, such that when the hot and humid air gets into contact with the components and/or inner surfaces, vapour in the hot and humid air will condensate and form droplets on the components, which may then cause the different problems discussed above.

[0013] By introducing a ventilation arrangement configured to draw air from within the housing to an outside of the housing, the risk of short-circuits, corrosion and malfunction of components of the tumble dryer is mitigated. The ventilation arrangement comprises a second fan arranged to generate a second flow of air passing through the ventilation arrangement to the outside of the housing, wherein the second flow of air is different from the flow of process air. The ventilation arrangement is arranged in a wall of the housing of the tumble dryer, such that air being drawn in by the second fan may escape through the ventilation arrangement to an outside of the housing. The ventilation arrangement may for example be installed in an opening in the housing. The second fan, when turned on, may draw air inside the housing towards the ventilation arrangement and let it escape through the housing. Since the flow of process air is a closed loop, the second flow of air is different from the flow of process air. The second flow of air may for example be hot and humid air that has escaped from the flow of process air, and flows freely within the housing, outside of the closed loop. According to an exemplifying embodiment of the present disclosure, the second flow of air is at least partially comprised by process air from the closed loop of process air, and at least partially comprised by ambient air. The interior of the housing may therefore comprise both ambient air, and the hot humid air that may have leaked during operation of the tumble dryer. By ventilating this air from within the housing through the ventilation arrangement to the outside of the housing, and thus forming the second flow of air, the hot and humid air may be ventilated out before its vapour condensates on components and/or inner surfaces within the housing. Thereby, the risk of damages to the components of the tumble dryer is minimized. This is further advantageous in that it prolongs the life cycle of the tumble dryer, and decreases the need for service and reparation, which could become costly for the consumer.

[0014] According to an exemplifying embodiment of the present disclosure, the ventilation arrangement further comprises a cover plate with a plurality of perforations, wherein the cover plate is arranged in a wall of the housing. The cover plate may be installed in the wall of the housing of the tumble dryer. The housing may comprise an opening in which the cover plate is installed. The perforations of the cover plate allow the second flow of air to escape from within the housing. The cover plate may for example be made from the same material as the housing. In one example, the cover plate with the plurality of perforations may be an integrated part of the housing. The plurality of perforations may be large enough to efficiently ventilate air from within the housing, but small enough for preventing objects to penetrate the perforations into the housing. The objects may for example be the finger of an operator, tools, etc. Thus, by having a cover plate with a plurality of perforations may advantageously prevent objects from reaching and possibly damaging the second fan or any other component inside the housing, as well as preventing the objects themselves from being damaged or injured by the second fan.

[0015] According to an exemplifying embodiment of the present disclosure, the second fan is arranged adjacent the cover plate with the plurality of perforations inside the housing. The second fan may be arranged close to the cover plate, and thus close to the plurality of perforations in the cover plate allowing the air to escape through the housing. This is advantageous in that the air drawn in by the second fan may immediately escape the housing from the second fan, instead of being led through an additional air duct to an opening far away from the second fan. The efficiency of the ventilation arrangement may thus be increased. It is also advantageous in that an arrangement of the second fan close to the cover plate saves space inside the housing.

[0016] According to an exemplifying embodiment of the present disclosure, the second fan and the plurality of perforations in the cover plate are coaxially arranged.

[0017] The plurality of perforations may for example be arranged in a pattern. For example, the plurality of perforations may be arranged in a circular pattern or multiple concentric circular patterns. The circular pattern may then be coaxially arranged with the axis of the second fan. This embodiment is advantageous since it allows the air exiting the second fan to escape through the housing in an efficient way, since the distance for the air to travel from the second fan to an outside of the housing is minimized.

[0018] According to an exemplifying embodiment of the present disclosure, the second fan is an axial fan. By "axial fan" is herein meant a fan causing the air to flow through it in an axial direction, parallel to the shaft about which the blades rotate. The flow of air passing the fan is thus axial at exit of the fan. The axis of the second fan may then be perpendicular to the plane of the wall of the housing where the ventilation arrangement is installed. This is advantageous in that it minimizes the deflection of the air when passing through the cover plate with a plurality of perforations, hence creates an efficient flow through the plurality of perforations. Moreover, the axis of the second fan may coincide with the central axis of the circular pattern of the plurality of perforations in the cover plate. In other examples, the second fan may be a propeller fan or a radial fan.

[0019] According to an exemplifying embodiment of the present disclosure, the ventilation arrangement further comprises a deflecting member configured to deflect a liquid entering the housing through the ventilation arrangement. The deflecting member may prevent a liquid entering the ventilation arrangement through the plurality of perforations in the cover plate to come into contact with the components inside the tumble dryer housing. Many tumble dryers have the requirement that their exterior (i.e., outside of the housing) need to be able to withstand to be flushed with a liquid, for example being cleaned with water or a cleaning liquid. By installing the ventilation arrangement, the risk of liquid reaching the inside of the housing and there getting in contact with sensitive components is increased. Such sensitive components may for example be electrical components where liquids such as water may cause short-circuits or other types of malfunctions. However, this problem is solved by the deflecting member, which deflects any liquid reaching the inside of the housing from the plurality of perforations in the cover plate. The deflecting member may be installed to deflect any liquid to an area inside the housing where no sensitive components are installed. For example, the deflecting member may be arranged to deflect the liquid towards an inner wall of the housing, such that the liquid runs down the inner wall of the housing to a bottom of the housing, where it may be drained. The housing may for example be made from a material able to withstand corrosion, such as stainless steel or aluminum. In further examples, the deflecting member may deflect the liquid into a closed duct for example, which conveys the liquid to a drain area in The housing. The duct may for example be made from a plastic material.

[0020] According to an exemplifying embodiment of the present disclosure, the deflecting member comprises an inclined wall, and at least one side wall, wherein the at least one side wall is attached to the cover plate of the ventilation arrangement. The inclined wall may be arranged such that the inclination directs the liquid to flow downwards towards a floor of the tumble dryer. The inclined wall may direct the liquid towards an inner wall of the housing. The inclined wall may further direct the liquid into a duct or similar component, directing the liquid towards a drain in the tumble dryer. The drain may for example be located in a bottom part of the tumble dryer housing, i.e., near the floor. The inclined wall thus efficiently directs the liquid away from sensitive components and prevents the liquid from being sprayed inside the housing. Instead, the liquid entering the housing through the plurality of perforations in the cover plate is gathered by the ventilation arrangement and directed to the same place, a place where the liquid may be drained.

[0021] The deflecting member further comprises at least one side wall, wherein the side wall is attached to the cover plate. The at least one side wall may further be attached to the inclined wall. The cover plate, the at least one side wall and the inclined wall may thus form one part. The at least one side wall may extend between the cover plate and the inclined wall. The at least one side wall may be arranged in such a way to further prevent liquid entering through the plurality of perforations from reaching sensitive components inside the housing. The part formed by the cover plate, the at least one side wall and the inclined wall may partly enclose the second fan. The deflecting member may be arranged in a corner of the housing, such that the cover plate is installed in one wall of the housing, and another wall of the housing forms a second side wall of the deflecting plate.

[0022] According to an exemplifying embodiment of the present disclosure, the at least one side wall is two side walls, and the second fan is arranged inside a space formed by the cover plate, the two side walls and the inclined wall. The second side wall may be a wall of the housing, or a separate side wall. When the two side walls are two separate side walls, i.e., separate from the walls of the housing, the ventilation arrangement may be placed in any position in a wall of the housing, where the cover plate is installed in the housing wall. The side walls prevent the liquid hitting the inclined wall from splashing out into the housing. Instead, it splashes against the side wall(s) and is guided by the inclined wall towards a location in the housing away from the sensitive components.

[0023] According to an exemplifying embodiment of the present disclosure, the ventilation arrangement is arranged in a top wall of the housing. Arranging the ventilation arrangement in a top wall of the housing is advantageous since hot, humid air rises, and will then by its own motion rise towards the ventilation arrangement, where it may be drawn in by the second fan and effectively ventilated out from the housing. In other examples, ventilation arrangement may be installed in a side wall of the housing, or in a rear wall of the housing. The ventilation arrangement may be installed in different positions in the housing to allow for different implementations of the tumble dryer and the ventilation arrangement.

[0024] According to an exemplifying embodiment of the present disclosure, the tumble dryer further comprises a control unit configured to control an operation of the tumble dryer. The control unit may control an operation of the tumble dryer by controlling an operation of the tumble dryer's internal components, for example the heat pump arrangement and the first fan. The control unit may be connected to the heat pump arrangement, and thus for example to the compressor, the expansion device and to sensors installed in the heat pump. These components may send and receive signal(s) from the control unit. The signal(s) sent to the control unit by the components may for example relate to a speed of the compressor, a temperature level in the heat pump or a speed of the first fan. According to an exemplifying embodiment of the present disclosure, the control unit is further configured to at least control an operation of the second fan and the heat pump arrangement. The control unit may for example control an on/off operation or a speed of the second fan. According to an exemplifying embodiment of the present disclosure, the control unit is configured to, based on an input from the heat pump arrangement, control the second fan to start or to stop. The control unit may for example control the second fan to be turned on when the compressor speed is above a predetermined threshold. This may for example mean that the tumble dryer is loaded with a large amount of wet laundry, which requires a higher compressor speed in order to efficiently dry the wet laundry within a given drying cycle, than a smaller amount of wet laundry would require. Moreover, the second fan may not need to be turned on during the entire drying cycle of the tumble dryer but may only be needed during parts of the drying cycle, when the most hot and humid air is circulated within the housing. The control unit may thus both control when to start and when to stop the second fan, in response to at least one input received from the heat pump arrangement and control a speed of the second fan. The control unit may thus efficiently ensure that hot, humid air is ventilated from within the housing while being energy efficient and not running the second fan when there is no hot, humid air to ventilate. In other examples, there may be a sensor installed in the housing, for example a humidity sensor, which may be connected to the control unit. In this example, the control unit may be connected to the humidity sensor and control the second fan to turn on and/or off upon an input from the humidity sensor. The second fan may then efficiently ventilate the humid air from the housing before it reaches and condenses on any of the internal surfaces and/or components therein.

Brief Description of the Drawings

[0025] Exemplifying embodiments will now be described in more detail, with reference to the following appended drawings:

Figure 1 shows a perspective view of a tumble dryer according to an exemplifying embodiment of the present disclosure;

Figure 2 shows a cross-sectional view of a tumble dryer according to an exemplifying embodiment of the present disclosure;

Figures 3a-b show detailed views of a ventilation arrangement arranged in a tumble dryer according to exemplifying embodiments of the present disclosure;

Figures 4a-c show views of a ventilation arrangement according to exemplifying embodiments of the present disclosure.

Detailed Description

[0026] As illustrated in the figures, the size of the elements and regions may be exaggerated for illustrative purposes and, thus, are provided to illustrate the general structures of the embodiments. Like reference numerals refer to like elements throughout.

[0027] Exemplifying embodiments will now be described more fully hereinafter with reference to the accompanying figures, in which currently preferred embodiments are shown. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled person.

[0028] With reference to Figure 1, a perspective view of a tumble dryer 100 according to an exemplifying embodiment of the present disclosure is shown. The tumble dryer 100 has a housing 110 with a front side 110a and a rear side 110b, and where the front side 100a is provided with a door 101 or hatch, attached to the front side with hinges. The door 101 in the housing 110 provides access to a rotatable drum (not shown) behind the door 101 where wet laundry may be loaded. The front side 100a further has a display unit 102. The display unit 102 may for example be used to display information to an operator or a user of the tumble dryer 100. The information may be details regarding the drying operation, for example a selected drying program, a remaining time of the drying program, a drying progress shown in percent, a drying temperature, etc. The housing 110 has a substantially rectangular cuboidal shape with two opposite side walls 110c, 110d (110d not visible in fig. 1), a top wall 111' and a bottom wall (not shown), in addition to the front side 110a and the rear side 110b. A ventilation arrangement 150 is arranged in the top wall 111' of the housing 110. The ventilation arrangement 150 is configured to ventilate air from within the housing 110 to an outside of the housing 200.

[0029] Figure 2 illustrates a cross-sectional view of the tumble dryer 100 according to an exemplifying embodiment of the present disclosure. As mentioned, the tumble dryer 100 comprises a rotatable drum 120 which is housed in the housing 110. The rotatable drum 120 extends along a depth D of the housing 110. The rotatable drum 120 may for example have a depth corresponding to ¾ of the depth D of the housing 110. A heat pump arrangement 140 is arranged partly behind the drum 120, to the right in fig. 2 towards the rear side 110b of the housing 110, and partly below the drum 120. The heat pump arrangement 140 comprises at least a compressor, a condenser, an evaporator and at least one expansion device (not shown). While the drum 120 rotates, a flow of process air F1 is fed therethrough. The flow of process air F1 is provided by a first fan 130, located in a space below the drum 120. A refrigerant is forced through the heat pump arrangement 140 by the compressor, which gathers energy in the evaporator and releases it in the condenser. The flow of process air F1 is achieved by means of the first fan 130, extracting hot and humid air from the drum 120. After passing the first fan 130 the flow of process air F1 arrives at the evaporator, which cools the flow of process air F1 such that vapour therein condenses into liquid water. This water may be collected in a bottom part of the housing 110 and may therefore be drained through a tube (not shown). The flow of process air F1, which is now cooler and contains less water, is passed to the condenser which heats the air again. The heated, dry air is reintroduced to the drum 120 where it is again capable of absorbing water from the wet laundry therein. The hot, humid flow of process air F1 is thereafter extracted by the first fan 130 again. Thereby, the flow of process air F1 forms a closed loop, illustrated by an arrow in fig. 2. The drum 120 is partly enclosed by a shell 121 that directs the flow of process air F1 exiting the drum 120 in a radial and then partly tangential direction towards the first fan 130 below the drum 120. Moreover, between the first fan 130 and the heat pump arrangement 140, there is a duct 122 directing the flow of process air F1 from the first fan 130 to the heat pump arrangement 140. The shell 121 and the duct 122 both enable the forming of a closed loop for the flow of process air F1. Moreover, the heat pump arrangement 140 is at least partly enclosed by a shell (not shown) that further enables the forming of a closed loop for the flow of process air F1.

[0030] Above the drum 120 in the housing 110 as depicted in fig. 2, there is a space 112. The space 112 within the housing 110 may house further components such as the display unit 102. The space 112 may further house other components such as a motor unit (not shown) for the rotatable drum 120. Air may leak from the flow of process air F1 out from the closed loop to the space 112 within the housing 110. The leaked air may include the hot, humid air from the drum 120, which may spread within the space 112 in the housing 110 and humidity may condense to form water drops when the hot, humid air comes into contact with the components housed in the space 112, or on the inner walls of the housing 110. The temperature inside the closed loop may be greater than a temperature outside the closed loop, within the space 112 in the housing 110.

[0031] The housing 110 further comprises a ventilation arrangement 150, in fig. 2 arranged in a top wall 111' of the housing 110. The ventilation arrangement 150 is configured to extract air from the space 112 within the housing 110 in a second flow of air F2, to an outside 200 of the housing 110. In other examples, the ventilation arrangement 150 may be arranged in a side wall (110c in fig. 1) of the housing 110, or in the rear side 110b of the housing 110. The second flow of air F2 flows from the space 112 within the housing 110 towards the ventilation arrangement 150, through the ventilation arrangement 150 and out on the outside 200 of the housing 110. Thereby, hot and humid air leaked from the flow of process air F1 may form part of the second flow of air F2, which is ventilated from the housing 110 by the ventilation arrangement 150. The second flow of air F2 is not a closed loop and may include air spread out inside the housing 110 at different locations. The arrows F2 in fig. 2 shows an example of different paths the second flow of air F2 may take towards and through the ventilation arrangement 150.

[0032] Figure 3a shows a perspective view of the ventilation arrangement 150 installed in the housing 110 of the tumble dryer 100. The ventilation arrangement 150 comprises a cover plate 151 arranged in the top wall 111' of the housing 110, and a second fan 160 arranged below the cover plate 151 on an inside 112 of the housing 110. The second fan 160 is configured to create the second flow of air F2 drawing air from inside the housing 110 and blowing it to an outside 200 of the housing 110. The second fan 160 is an axial fan. Moreover, the ventilation arrangement 150 comprises a deflection member. The deflection member comprises an inclined wall 153 and two side walls 155a, 155b (155a not visible in fig. 3a). The inclined wall 153 is arranged below the second fan 160 as seen in present fig. 3a. The inclined wall 153, the two side walls 155a, 155b and the cover plate 151 together forms a partly enclosed space 161 in which the second fan 160 is arranged. The two side walls 155a, 155b extends between the inclined wall 153 and the cover plate 151. In the present example, where the ventilation arrangement 150 is installed in a top wall 111' of the housing 110, the cover plate 151 is horizontal and shares a plane with the top wall 111' of the housing 110, while the two side walls 155a, 155b are vertical. The cover plate 151, the two side walls 155a, 155b and the inclined wall 153 thus forms a structure similar to a box with two open ends, with an inclined bottom wall 153.

[0033] Figure 3b shows a cross-sectional view of the ventilation arrangement 150 installed in the housing 110 of the tumble dryer 100. The inclined wall 153 has a higher end 153a and a lower end 153b. The lower end 153b is arranged adjacent to a side wall 110d of the housing. Thereby, a liquid entering the ventilation arrangement 150 from an outside 200 of the housing 110, may flow down the inclined wall 153 and exit the ventilation arrangement 150 at the lower side 153b of the inclined wall 153, and thereafter flow down along the side wall 110d of the housing 110. Therefore, the liquid may be deflected by the inclined wall 153 and directed towards an inner wall 110d of the housing 110. By doing this, the liquid is prevented from reaching sensitive components inside the housing 110, possibly damaging them.

[0034] Figure 4a illustrates a perspective view of the ventilation arrangement 150. The cover plate 151 of the ventilation arrangement 150 comprises a plurality of perforations 152. The plurality of perforations 152 are arranged in a circular pattern with perforations arranged in multiple concentric circles. The circular pattern of the plurality of perforations 152 and the second fan 160 are coaxially arranged around axis A. Moreover, the second fan 160 is attached to the cover plate 151 by means of mechanical fasteners 154. The second flow of air F2 may therefore enter the ventilation arrangement 150 on either side of the open sides 150a, 150b of the ventilation arrangement 150, and be extracted by the second fan 160 from underneath the second fan 160. The second flow of air F2 may thereafter exit the cover plate 151 and the ventilation arrangement 150 through the plurality of perforations 152. The cover plate 151 may be arranged in an opening in the wall of the housing 110, and be attached by means of mechanical fasteners, for example. A liquid entering the ventilation arrangement 150 through the plurality of perforations 152 is deflected by the inclined wall 153 and the two side walls 155a, 155b, and directed towards the open end 150a of the ventilation arrangement 150. The liquid may thereafter flow down towards a bottom side of the housing 110 where it may be drained. The two side walls 155a, 155b prevents the liquid from splashing out into the space 112 inside the housing 110 where it may end up damaging a component housed therein.

[0035] Figure 4b illustrates a top view of the ventilation arrangement 150, where the plurality of perforations 152 are seen arranged in a circular pattern. The circular pattern may comprise perforations arranged in multiple concentric circles, all arranged around axis A. Figure 4c illustrates a cross-sectional view of a ventilation arrangement 150. The inclined wall 153 is inclined with an angle β with respect to the horizontal axis B. The angle β may range from 0 to 45°, for example.

[0036] Although features and elements are described above in particular combinations, each feature or element can be used alone without the other features and elements or in various combinations with or without other features and elements.

[0037] Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed invention, from a study of the figures, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain features are recited in mutually different dependent claims does not indicate that a combination of these features cannot be used to advantage.

Claims

1. A tumble dryer (100), comprising:

a housing (110);

a rotatable drum (120) arranged in the housing (110);

a first fan (130) arranged to generate a flow of process air passing through the rotatable drum (120);

a heat pump arrangement (140) arranged in the flow of process air; wherein

the heat pump arrangement (140) is configured to heat and dry the process air; and

a ventilation arrangement (150) arranged in a wall (111) of the housing (110) and configured to draw air from within the housing (110) to an outside (200) of the housing (110);
wherein

the ventilation arrangement (150) comprises:
a second fan (160) arranged to generate a second flow of air passing through the ventilation arrangement (150) to the outside of the housing (200); and wherein the flow of process air and the second flow of air are separate from each other.

2. Tumble dryer (100) according to claim 1, wherein the ventilation arrangement (150) further comprises a cover plate (151) with a plurality of perforations (152), wherein the top plate (151) is arranged in a wall (111) of the housing (110).

3. Tumble dryer (100) according to claim 2, wherein the second fan (160) is arranged adjacent the cover plate (151) with the plurality of perforations (152) inside the housing (110).

4. Tumble dryer (100) according to claim 3, wherein the second fan (160) and the plurality of perforations (152) in the cover plate (151) are coaxially arranged.

5. The tumble dryer (100) according to any one of the preceding claims, wherein the ventilation arrangement (150) further comprises a deflecting member (153) configured to deflect a liquid entering the housing (110) through the ventilation arrangement (150).

6. The tumble dryer (100) according to claims 2 and 5, wherein the deflecting member (153) comprises an inclined wall, and at least one side wall (155), wherein the at least one side wall (155) is attached to the cover plate (151) of the ventilation arrangement (150).

7. The tumble dryer (100) according to claim 6, wherein at least one side wall (155) is two side walls (155a, 155b), and the second fan (160) is arranged inside a space (161) formed by the cover plate (151), the two side walls (155a, 155b) and the inclined wall (153).

8. The tumble dryer (100) according to any one of the preceding claims, wherein the ventilation arrangement (150) is arranged in a top wall (111') of the housing (110).

9. The tumble dryer (110) according to any one of the previous claims, wherein the second fan (160) is an axial fan.

10. The tumble dryer (100) according to any one of the preceding claims, further comprising a control unit configured to control an operation of the tumble dryer (100).

11. The tumble dryer (100) according to claim 10, wherein the control unit is further configured to at least control an operation of the second fan (160) and the heat pump arrangement (140).

12. The tumble dryer (100) according to claim 11, wherein the control unit is configured to, based on an input from the heat pump arrangement (140), control the second fan (160) to start or to stop.

13. The tumble dryer (100) according to any one of the preceding claims, wherein the flow of process air is a closed loop passing the heat pump arrangement (140), the rotating drum (120), and the first fan (130).

14. The tumble dryer (100) according to claim 12, wherein the second flow of air is at least partially comprised by process air from the closed loop of process air, and at least partially comprised by ambient air.

Drawing