Flow-optimised diffuser

Abstract

The invention relates to a diffuser for guiding a process air flow generated by a fan into a laundry drum, comprising an air duct with an inlet for introducing the process air flow into the air duct and comprising at least one outlet for discharging the process air flow from the air duct. The air duct is designed to be arranged at the rear of the laundry drum in a household appliance. The air duct has a curved profile from the inlet to the outlet, the at least one outlet being oriented in the direction of the laundry drum due to the curved profile of the air duct. The invention further relates to an arrangement and a household appliance.

Description

[0001] The present invention relates to a diffuser for guiding a process air stream into a laundry drum, comprising an air duct with an inlet into the air duct and at least one outlet for discharging the process air stream from the air duct. Furthermore, the invention relates to an arrangement and a household appliance.

[0002] Tumble dryers use a heated process air stream to warm textiles within a laundry drum and to absorb moisture from the textiles. The process air stream, laden with moisture from the textiles, is then directed out of the laundry drum and, particularly in modern tumble dryers, cooled to condense the absorbed moisture. Cooling the process air stream thus enables dehumidification of the process air stream. The process air stream can then be heated and re-directed into the laundry drum. The process air stream is normally guided from the fan into the laundry drum through a diffuser located at the rear. A blower or fan is normally used to implement this type of process air stream circulation. The fan is usually located below the laundry drum and is driven directly or via a belt drive by a motor in the laundry drum.Such a tumble dryer is known, for example, from EP 2 527 525 B1.

[0003] The shape of the diffuser, which is located downstream of the fan wheel, significantly influences the resulting process air flow of the fan and thus the efficiency of the fan wheel. The installation space in the tumble dryer at the rear of the laundry drum is severely limited, which is why the diffuser is usually designed to be flat and wide in order to direct the process air flow into the laundry drum. The process air flow generated by the fan is deflected by 90° as it enters the diffuser and is deflected again by 90° as it leaves the diffuser towards the laundry drum. DE 10 2015 100 315 B4 discloses a diffuser in which the process air flow is directed into the laundry drum below and above the rotational axis of the drum. Such deflection usually reduces the volume flow of the process air flow and therefore requires compensation through a corresponding increase in the performance of the fan drive.However, this measure increases energy consumption, contrary to current efforts to reduce the overall energy consumption of tumble dryers.

[0004] It is therefore the object of the present invention to provide a diffuser and an arrangement by means of which a reduction in the overall energy consumption of household appliances, such as tumble dryers, is possible.

[0005] This object is achieved by a diffuser having the features of claim 1, by an arrangement having the features of claim 7 and by a household appliance having the features of claim 12.

[0006] According to one aspect of the present invention, a diffuser for guiding a process air stream into a laundry drum is provided. The diffuser comprises an air duct with an inlet into the air duct and at least one outlet for discharging the process air stream from the air duct.

[0007] Advantageously, the air duct is designed to be arranged at the rear of the laundry drum in a household appliance, wherein the air duct has a curved course from the inlet to the outlet, wherein the at least one outlet is oriented towards the laundry drum due to the curved course of the air duct. The at least one outlet and the inlet can be oriented towards the laundry drum due to the curved course of the air duct in such a way that the process air flow can pass from the inlet into the air duct and from the air duct into the outlet with or without a minimal change of direction. A minimal change of direction can, for example, comprise a deflection of the process air flow by 45° or less. In this way, the 90° changes of direction, which are detrimental to the flow velocity, can be avoided.

[0008] In series devices, the diffuser, especially the outlet of the air duct, represents a bottleneck for the process air flow. By using a back-curved air duct, the efficiency of the fan wheel can be increased and the pressure loss of the process air flow can be reduced.

[0009] The flow-optimized shape of the diffuser also improves the flow distribution at the inlet to the laundry drum and at the outlet of the air duct. This optimization can improve the interaction between hot process air and wet laundry in the laundry drum.

[0010] Furthermore, the pressure resistance of the diffuser is reduced by enlarging the narrowest points of the air duct and preventing vortex formation. The change in flow direction at the end of the diffuser toward the drum is less abrupt due to the curved shape. The resulting lower pressure resistance allows the fan speed to be set to a lower value while maintaining the same flow rate, thus also reducing the power consumption of the fan drive. The reduced speed has a positive effect on noise emissions and vibrations of the rotating components.

[0011] According to a further aspect of the invention, an arrangement for a household appliance is provided. The arrangement comprises a laundry drum, a fan, and a diffuser according to the invention. The laundry drum is designed to be open at the front for inserting textiles and has at least one opening at the rear for introducing process air. The diffuser is arranged at the rear of the laundry drum such that an outlet of an air duct of the diffuser opens into or at the at least one opening of the laundry drum. The fan is configured to generate a process air flow that can be fed directly or indirectly into the air duct via an inlet of the diffuser. The process air flow can be deflected evenly or continuously from the inlet to the outlet by means of a curved course of the air duct formed along a width direction and / or depth direction.

[0012] The fan can consist of a fan drive and a fan wheel. The fan drive can be designed as an electric motor that can drive the fan wheel directly or indirectly. The fan wheel can be designed, for example, as an axial fan or a radial fan.

[0013] According to a further aspect of the invention, a household appliance with an arrangement according to the invention is provided. The arrangement can be installed in a housing and connected to a base module.

[0014] The household appliance can be designed, for example, as a washer-dryer, a tumble dryer or as a washing machine with an air supply into the laundry drum.

[0015] For example, the base module of the household appliance can include heat exchangers for heating and cooling the process air flow. The fan can generate the process air flow and pass it through the laundry drum and the heat exchangers to create a cycle for dehumidifying textiles or for ventilating textiles.

[0016] In one embodiment, the air duct widens at least in the width direction starting from the inlet and is essentially funnel-shaped. This measure allows the free cross-sectional area of ​​the air duct to increase progressively or continuously. Such a design enables uniform or steady outflow conditions for the impeller or fan. The process air flow is constantly accelerated and never slowed down by a contraction of the cross-sectional area. This also prevents recirculation areas and vortex formation. Such optimized flow conditions allow the fan to operate with reduced torque at the same volume flow, thereby reducing the power consumption of the fan drive, for example an electric motor.

[0017] According to a further embodiment, the curved air duct is C-shaped, at least in some regions, along a depth direction. Alternatively or additionally, the air duct is curved, in particular C-shaped, starting from the inlet along the width direction. Such a shape of the air duct enables particularly flow-optimized guidance of the process air flow from the fan into the laundry drum. In particular, the shape of the air duct itself can divert the process air flow, so that the end sections at the inlet and outlet are no longer used to abruptly change the direction of the air flow. Depending on the design of the air duct, it can also have an S-shape, with the outlet oriented towards the laundry drum.

[0018] According to another embodiment, the air duct is formed by a first, rear shell and a second, front shell. This measure allows for particularly simple technical production of the diffuser. For example, a 3D printing process or an injection molding process can be used for this purpose. The two shells can be locked, screwed, glued, and / or welded together to form the diffuser.

[0019] The two shells can have one or more connecting areas in the flow direction and / or transverse to the flow direction of the process air through the air duct, where the shells meet to form at least the air duct of the diffuser. Depending on the design, the complete diffuser can consist of two or more shells.

[0020] According to a further embodiment, the curved course of the air duct along a width direction and / or depth direction is formed by a curved first shell and / or a curved second shell. This allows the flow-optimized shape of the air duct to be created by various minor or more extensive modifications to the air duct.

[0021] According to a further embodiment, the air duct has a rectangular, square, oval, and / or rounded cross-sectional shape, at least in some areas. This measure allows the process air flow to be guided through a customized cross-section, which is adapted to the rear installation space requirements of the household appliance. Thus, the installation space behind the laundry drum can be optimally utilized.

[0022] The diffuser can be used in a particularly versatile manner if the inlet has a spiral section, particularly for accommodating a fan impeller, or if the inlet is arranged downstream of the spiral section in the direction of flow. Thus, the inlet into the air duct can begin with the section accommodating the fan impeller or be located downstream of this section.

[0023] According to a further embodiment, the diffuser has an extension along a vertical direction such that the outlet opens below a rotational axis of the laundry drum at the opening of the laundry drum. This allows the length or elongated extension of the air duct in the flow direction of the process air flow to be kept particularly short, thereby minimizing flow resistance.

[0024] According to a further embodiment, the laundry drum has at least two rear openings. The diffuser extends along a height direction and / or width direction such that the at least one outlet opens below a rotation axis and / or above a rotation axis of the laundry drum at the at least one opening of the laundry drum. Thus, an extended air duct can be provided, which opens at two rear openings of the laundry drum. This measure enables more even heating of the textiles in the laundry drum.

[0025] According to a further embodiment, the at least one rear opening of the laundry drum is substantially semicircular. This maximizes the cross-section for the process air outlet. The at least one outlet of the air duct is configured to at least partially enclose and / or cover the opening of the laundry drum. This measure reduces pressure losses at a transition between the diffuser or an outlet of the air duct and the inlet or rear opening of the laundry drum.

[0026] According to a further embodiment, the fan is driven by a first electric motor directly or indirectly via a mechanical connection to a second electric motor to rotate the laundry drum. The fan and, in particular, the fan wheel can thus be driven independently by a direct drive via the first electric motor. In an alternative embodiment, a second electric motor, which can be provided as the only electric motor in the household appliance, can drive the laundry drum and the fan wheel. Such an indirect drive can be achieved via a mechanical connection in the form of a belt, chain, gear, drive shaft, and the like.

[0027] The advantages and features explained above in connection with the device also apply analogously to the method, and vice versa. Individual features or aspects of the present invention can be combined with one another and have the advantages explained in this context.

[0028] The invention will be explained in detail below using advantageous embodiments with reference to the attached figures. Fig. 1 shows a perspective view of the rear of a household appliance according to an embodiment without a housing. Fig. 2 shows a schematic sectional view of an arrangement according to an embodiment. Fig. 3 shows a further sectional view of the arrangement from Fig. 2 to illustrate a diffuser according to the invention according to one embodiment.

[0029] In the figures, identical or corresponding elements are designated by the same reference numerals. Factors such as numerical values, shapes, components, positions of components, and the manner in which components are connected are merely illustrative and not limiting. Different scales have been used in some drawings for clarity and ease of understanding.

[0030] Fig. 1 shows a perspective view of a rear side of a household appliance 100 according to one embodiment. For clarity, the household appliance 100 is shown without a housing.

[0031] The household appliance 100 has an arrangement 10 according to the invention, which in the Fig. 2 and Fig. 3 is illustrated in more detail. In the exemplary embodiment shown, the household appliance 100 is designed, for example, as a tumble dryer.

[0032] The arrangement 10 comprises a laundry drum 11, a fan 20, and a diffuser 30. The laundry drum 11 is open at the front for inserting textiles and has at least one opening 12 at the rear for introducing process air. The diffuser 30 is arranged at the rear of the laundry drum 11. The diffuser 30 consists of a first shell 31, a second shell 32, and a third shell 33, wherein the third shell 33 is configured to provide access to a first electric motor 21, which can directly drive a fan impeller 22 of the fan 20.

[0033] The fan wheel 22 is arranged in a spiral section 37, which enables a particularly optimal flow distribution of the resulting process air flow. The spiral section 37 can be a component of the diffuser 30. Depending on the design, the spiral section 37 can also be formed by the shells 31, 32, 33.

[0034] The third shell 33 is inserted into a recess or opening in the first shell 31 and is attached to it. The first shell 31 forms a rear side of the diffuser 30, which is directed away from the laundry drum 11. The second shell 32 is directed towards the laundry drum 11 and is in the Fig. 2 and Fig. 3 shown.

[0035] The household appliance 100 further comprises a base module 110, which also includes a second electric motor 111 for rotating the laundry drum 11. The second electric motor 111 can rotate the laundry drum 11 about a rotation axis R with the aid of a belt drive.

[0036] In the base module 110 of the household appliance 100, additional components, not numbered or shown, such as heat exchangers for heating and cooling the process air flow, may be provided. The fan 20 can generate the process air flow and guide it through the laundry drum 11 and the heat exchangers to create a circuit for dehumidifying textiles in the laundry drum 11 or for ventilating textiles. Fig. 3 the process air flow within the diffuser 30 is schematically visualized by arrows.

[0037] The Fig. 2 shows a schematic sectional view of an arrangement 10 according to an embodiment. In particular, the arrangement 10 of the Fig. 1 shown household appliance 100 without the first shell 31 and the third shell 33 of the diffuser 30 in order to illustrate a course of an air duct 34 of the diffuser. The arrows illustrate the continuous increase in the extent of the air duct 34 along a width direction B of the household appliance 100 along a height direction H. The extent of the air duct 34 increases along the width direction B such that the air duct 34 opens into an outlet 35, which essentially corresponds in size to the rear opening 12 of the laundry drum 11.

[0038] Also visible are the fan wheel 22 and the first electric motor 21, which generate the process air flow. In the illustrated embodiment, the fan wheel 22 is designed as a radial fan. The fan wheel 22 is located in the area of ​​an inlet 36 of the air duct 34.

[0039] In the Fig. 2 It is also made clear that the rear opening 12 of the laundry drum 11 is located below the axis of rotation R, so that the extension of the air duct 34 between the outlet 35 and the inlet 36 can be designed to be particularly short.

[0040] Fig. 3 shows a further sectional view of the arrangement 10 from Fig. 2 to illustrate a diffuser 30 according to the invention according to one embodiment. It is illustrated here that the outlet 35 of the air duct 34 of the diffuser 30 opens into or at the at least one rear opening 12 of the laundry drum 11.

[0041] The fan 20, in particular the fan wheel 22, generates a process air flow (see arrows), which is fed directly or indirectly via the inlet 36 into the air duct 34.

[0042] The process air flow is then deflected uniformly or continuously from the inlet 36 to the outlet 35 by means of a curved course of the air duct 34 formed along the width direction B and / or the depth direction T. By way of example, Fig. 3 an embodiment of the diffuser 30 is shown in which the helical section 37 functions as an inlet 36. In contrast to this, in the Fig. 1 and Fig. 2 the inlet 36 of the diffuser 30 is arranged downstream of the helical section 37.

[0043] In the illustrated embodiment, the curved course of the air duct 34 is particularly pronounced in the depth direction T, so that the process air flow is first guided away from the laundry drum 11 along the depth direction and then directed toward the laundry drum 11 via the curved course. The air duct 34 is designed, for example, in a C-shape. List of reference symbols

[0044] 100 -Household appliance 110 -Base module 111 -Second electric motor 10 -arrangement 11 -washing drum 12 -rear opening of the 20 -Fan 21 -First electric motor 22 -Fan wheel 30 - diffuser 31 - first shell 32 - second shell 33 - third shell 34 - air duct 35 - outlet 36 - inlet 37 - spiral section T -depth direction H -height direction B -width direction R -rotation axis

Claims

1. A diffuser (30) for guiding a process air flow generated by a fan (20) into a laundry drum (11), comprising an air duct (34) with an inlet (36) for introducing the process air flow into the air duct (34) and comprising at least one outlet (35) for discharging the process air flow from the air duct (34), wherein the air duct (34) is configured to be arranged at the rear of the laundry drum (11) in a household appliance (100), wherein the air duct (34) has a curved course starting from the inlet (36) and extending to the outlet (35), wherein the at least one outlet (35) is oriented in the direction of the laundry drum (11) due to the curved course of the air duct (34).

2. Diffuser according to claim 1, wherein the air duct (34) widens from the inlet (36) to the outlet (35) at least in the width direction (B) and is substantially funnel-shaped ​3. Diffuser according to claim 1 or 2, wherein the curved air duct (34) is C-shaped at least in some regions along a depth direction (T) and / or wherein the air duct (34) is curved, in particular C-shaped, starting from the inlet (36) along the width direction (B).

4. Diffuser according to one of claims 1 to 3, wherein the air channel (34) is formed by a first, rear, shell (31) and a second, front, shell (32).

5. Diffuser according to claim 4, wherein the curved course of the air duct (34) along a width direction (B) and / or depth direction (T) is formed by a curved first shell (31) and / or by a curved second shell (32).

6. Diffuser according to one of claims 1 to 5, wherein the air duct (34) has at least partially a rectangular, square, oval and / or rounded cross-sectional shape. ​7. Diffuser according to one of claims 1 to 6, wherein the inlet (36) has a helical section (37), in particular for receiving a fan wheel (22), or wherein the inlet (36) is arranged downstream of the helical section (37) in the flow direction. ​8. Arrangement (10) for a household appliance (100), comprising a laundry drum (11), a fan (20) and a diffuser (30) according to one of the preceding claims, wherein the laundry drum (11) is designed to be open at the front for inserting textiles and has at least one opening (12) at the rear for introducing process air, wherein the diffuser (30) is arranged at the rear of the laundry drum (11) in such a way that an outlet (35) of an air duct (34) of the diffuser (30) opens into the at least one opening (12) of the laundry drum (11), wherein the fan (20) is designed to generate a process air flow which can be introduced directly or indirectly via an inlet (36) into the air duct (34), wherein the process air flow is uniformly distributed from the inlet by means of a curved course of the air duct (34) formed along a width direction (B) and / or depth direction (T) (36) can be deflected to the outlet (35).

9. Arrangement according to claim 8, wherein the diffuser (30) has such an extension along a height direction (H) that the outlet (35) opens below a rotation axis (R) of the laundry drum (11) at the opening (12) of the laundry drum (11).

10. Arrangement according to claim 8, wherein the laundry drum (11) has at least two rear openings (12), wherein the diffuser (30) has an extension along a height direction (H) and / or width direction (B) such that the at least one outlet (35) opens below a rotation axis (R) and / or above the rotation axis (R) of the laundry drum (11) at the at least one opening (12) of the laundry drum (11). ​11. Arrangement according to one of claims 8 to 10, wherein the at least one rear opening (12) of the laundry drum (11) is substantially semicircular, wherein the at least one outlet (35) of the air duct (34) is configured to at least partially enclose and / or cover the opening (12) of the laundry drum (11).

12. Arrangement according to one of claims 8 to 11, wherein the fan (20) is driven by a first electric motor (21) directly or indirectly via a mechanical connection of a second electric motor (111) for rotating the laundry drum (11).

13. Household appliance (100), comprising an arrangement (10) according to one of claims 8 to 12.​

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