EP4632140A1

EP4632140A1 - Assembly and appliance with improved efficiency

Info

Publication number: EP4632140A1
Application number: EP24168949.6A
Authority: EP
Inventors: Manoochehr DARVISH; Dawid Weglarski; Adam Zarzycki
Original assignee: BSH Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2024-04-08
Filing date: 2024-04-08
Publication date: 2025-10-15
Also published as: CN120777749A

Abstract

The present invention relates to an assembly (10) for an appliance, comprising a process air channel (11), an air nozzle (20), at least one heat exchanger (30) and a fan wheel (12), wherein the process air channel (11) connects the heat exchanger (30) with the fan wheel (12), wherein the air nozzle (20) comprises an inlet opening to collect tempered air from the heat exchanger (30), a funnel-shaped tube section (23) and an outlet opening (21) to guide a collected air flow to the fan wheel (12), wherein the air nozzle (20) comprises a straightening section (24) in flow direction of the air, prior to the outlet opening (21). Furthermore, the present invention relates to an air nozzle (20) of an appliance and to an appliance with the said assembly.

Description

The present invention relates to an assembly for an appliance, comprising a process air channel, an air nozzle, at least one heat exchanger and a fan wheel. Furthermore, does the present invention relate to an air nozzle of an appliance and to an appliance with the said assembly.
Tumble dryers are usually equipped with process fan wheels in order to move heated process air to the drum and to remove humid air from the drum. The humidity filled air is regularly guided through heat exchanger resulting in drying the process air by condensation and re-heating. The process fan wheel is made of plastic or metal and is driven by an electric motor for creating the main air flow in appliance. The efficiency of the fan wheel is a characteristic feature, which describes how much of the electrical energy consumption of the motor is converted into hydraulic energy of the process air by the fan wheel. In order to use the fan wheel in a most efficient way it is required to connect the fan wheel to an optimized air duct system.
The part of the process air channel that guides the air flow towards the fan wheel is the air nozzle. Moreover, the air nozzle usually connects a heating element with the fan wheel and is arranged with the fan wheel in the bottom group or bottom module of the appliance. In order to utilize the space in the bottom group, the air nozzle is formed as a curved channel. Such curvature of the air nozzle impairs the efficiency of the fan wheel due to uneven velocity distribution of the air at the entrance of the fan wheel.
It is therefore an object of the present invention to provide an assembly and an appliance with improved efficiency.
This problem is solved by an assembly according to claim 1, by an air nozzle according to claim 9 and by an appliance according to the features of claim 10. Advantageous embodiments are set out in the dependent claims.
According to one aspect of the present invention, an assembly for an appliance is provided. The assembly comprises a process air channel, an air nozzle, at least one heat exchanger and a fan wheel. Thus, the assembly may form a part or an entire process air channel of an appliance. The fan wheel is driven by a motor which is arranged outside the process air channel. The fan wheel is positioned inside the process air channel and is utilized in order to create an air flow through the process air channel.
The at least one heat exchanger is also arranged inside the process air channel. Thus, the fan wheel may suck or push the air from or to the heat exchanger in order to cool and/or heat the air inside the process air channel. The process air channel connects the heat exchanger with the fan wheel.
The fan wheel may be an axial or radial fan wheel. The air nozzle comprises an inlet opening to collect tempered air from the heat exchanger. Moreover, the air nozzle comprises an outlet opening to guide a collected air flow to a fan wheel. The outlet opening is provided in order to collect air from the heat exchanger. A funnel-shaped tube section is able to concentrate or adjust the collected air from a cross section of the heat exchanger to a cross section of the fan wheel. Between the outlet opening and the funnel-shaped tube section a straightening section is formed.
Due to the reduction or change of the cross section between the fan wheel and the heat exchanger, an uneven velocity distribution is formed at the entrance to the fan wheel. Such effects usually occur due to local increase of velocity near the walls resulting from the decrease of the cross section of the air flow. By providing the straightening section, the air flow may be straightened and the standard deviation of the velocity distribution may be reduced. Thus, the more even or smooth air velocity distribution inside the air channel cross-section before entering the fan wheel results in higher efficiency and lower energy consumption.
Based on a further aspect of the invention an air nozzle for an appliance is provided. The air nozzle comprises an inlet opening that is configured to collect tempered air from the heat exchanger, a funnel-shaped tube section and an outlet opening that is configured to guide a collected air flow to a fan wheel. Furthermore, the air nozzle comprises a straightening section which is connecting the outlet opening with the funnel-shaped tube section.
In a further aspect of the invention an appliance, especially formed as a home appliance, is provided. For example the appliance may be formed as tumble dyer, washer dryer, steam cooker, steam treatment device, dishwasher. In particular, the appliance may comprise a process air channel for guiding an air flow. The process air channel may be formed as a loop or may be formed opened in order to provide an air flow or any gas flow, e.g. steam, warm air, cool air and the like, to a treatment space. Such treatment space may be formed as a drum or a washing area or a cooking area.
Based on an embodiment, the straightening section is formed as a straight tube with constant or variable diameter. Thus, the air nozzle may be manufactured technically easy. Straight may be defined as unbowed or without curvature in direction of the air flow. The direction of the air flow may be defined as a direction that connects the fan wheel with the heat exchanger.
Moreover, based on a further embodiment, at least a part of the straightening section is formed with an angle or a curve. Thus, the straightening section may comprise Inclined walls and/or walls with one or more curved parts.
In a further embodiment, the straightening section is aligned in an angle of 90° or less relative to a rotation axis of the fan wheel. Thus, the whole straightening section may be aligned inclined or angled with regard to the rotation axis of the fan wheel. Moreover, the straightening section may at least partially comprise a conical shape with a larger opening towards the heat exchanger. An entire opening angle of the straightening section with a conical shape may be up to 5° in converging direction and up to 5° in diverging direction.
The alignment of the entire straightening section and the possible form and deviation of the walls of the straightening section from a straight pipe form may be determined technically easy by performing a CFD analysis of the geometry of the process air channel with the fan wheel and heat exchangers.
The fan wheel and the heat exchanger may be arranged flush-aligned. Thus, in flow direction of the air flow inside the process air channel the fan wheel and the heat exchanger are arranged in a straight line or do not comprise any or marginal offset in a direction transverse to the air flow direction between the fan wheel and the heat exchanger. Such configuration allows a more uniform distribution of the air flow velocity within the cross section of the process air channel.
According to another embodiment, the air nozzle comprises a cross-section with a symmetrical or asymmetrical shape. Thus, the air nozzle may connect the fan wheel with the heat exchanger even when their positions may deviate from each other.
In a further embodiment, the funnel-shaped tube section of the air nozzle comprises curved and/or straight shaped walls reducing a cross section of the air nozzle starting from the inlet opening to the straightening section of the air nozzle. By providing an air nozzle with straight walls, the manufacturing costs may be reduced. The air nozzle with curved walls may provide improved fluid dynamic characteristics due to smooth and steady flow of the air at the walls.
Based on a further embodiment, the straightening section of the air nozzle comprises a ratio of length to diameter of 0.2 or more. Due to the uneven velocity distribution of the air flow inside the air nozzle which results from the reduction of the cross section, the velocity at the walls is increased due to inertia of air flowing from a wider to narrower section of the straightening section. By utilizing the straightening section the natural friction of the air flow near the walls may act and locally slow down the air flow with increased velocity. The ratio of at least 0.2 between the diameter of the outlet opening of the straightening section and the length of the straightening section enables a technically easy improvement in the velocity distribution of the air flow such the variations of the velocity at the outlet opening of the air nozzle are reduced.
In a further embodiment, the straightening section and/or the funnel-shaped tube section at least locally comprises guiding ribs and/or at least one grid (for example honey comb or and/or lattice) and/or at least one wall structure formed inside of the air nozzle. By providing such structures like ribs, grids and the like, the straightening and smoothing effect of the straightening section on the velocity distribution may be further improved. The precise velocity distribution at the outlet opening may be obtained by measurements or by CFD analysis or simulation of a given geometry configuration of the air nozzle. Thus, by integrating wall structures additional friction may be provided locally limited in order to adjust the velocity distribution prior to entering the fan wheel more precisely.
Based on a further embodiment, the funnel-shaped tube section is formed asymmetrically and comprises at least partially at least one long wall and at least one short wall, wherein at least one wall structure is attached at or integrated into the long wall. Due to the resulting pressure distribution within the funnel-shaped tube section the higher pressure may be expected in the area of the longer wall where a larger volume of air is squeezed into a smaller cross section. Thus, the higher velocity of the air adjacent to the longer wall may be reduced by the wall structure more than by a usual wall of the funnel-shaped tube section of the straightening section. The long wall and the short wall may be formed as parts or sections of the walls of the nozzle.
In accordance with a further embodiment, the the straightening section and the funnel-shaped tube section of the air nozzle are integrally formed, or wherein the straightening section and the funnel-shaped tube section are detachably connected with each other. Thus, the air nozzle may be flexibly manufactured as a one-piece component or as a multiple-part component.
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 each other and have the advantages explained in this context.
In the following, the invention is explained in detail by means of advantageous embodiments with reference to the attached figures. The figures show:

Fig. 1: a schematic cross-section illustrating an assembly for a household appliance according to an embodiment.

In the figures, identical or corresponding elements are labelled with the same reference signs. Values and characteristics such as numerical values, shapes, components, positions of components and the way in which the components are connected to each other are merely illustrative and not restrictive. For reasons of clarity and to improve recognisability, different scales are sometimes used in the drawings.
Fig. 1 shows a schematic cross-section illustrating an assembly 10 for a household appliance according to an embodiment of the invention. The assembly 10 comprises a process air channel 11, an air nozzle 20, at least one heat exchanger 30 and a fan wheel 12. The assembly 10 may be formed as a part or a whole process air channel of the appliance. For example the appliance may be formed as tumble dyer, washer dryer, steam cooker, steam treatment device, dishwasher. In shown particular example, the appliance is formed as a tumble dryer.
The fan wheel 12 is driven by a motor 13 which is arranged outside the process air channel 11. The fan wheel 12 is positioned inside the process air channel 11 and is utilized in order to create an air flow through the process air channel 11. The arrows are indicating the direction D of the air flow. In the shown embodiment, the fan wheel 12 is a radial fan wheel that is sucking in air in the direction D. The air leaves the fan wheel 12 in a direction transversal to the direction D.
The at least one heat exchanger 30 is also arranged inside the process air channel 11. Thus, the fan wheel 12 may suck the air from the heat exchanger 30 in order to heat the air inside the process air channel 11 after the heat exchanger 30. The process air channel 11 connects the heat exchanger 30 with the fan wheel 12 via the air nozzle 20 which also forms a part or section of the process air channel 11.
The process air channel 11 is for example formed as a loop in order to provide an air flow to a treatment space like a drum of the appliance.
The air nozzle 20 comprises an inlet opening 22 that is configured to collect tempered air from the heat exchanger 30, a funnel-shaped tube section 23 and an outlet opening 21 that is configured to guide a collected air flow to the fan wheel 12. Furthermore, the air nozzle 20 comprises a straightening section 24 which is connecting the outlet opening 21 with the funnel-shaped tube section 23.
The funnel-shaped tube section 23 is formed asymmetrically and comprises at least one long wall 25 and at least one short wall 26. At least one wall structure may be attached at an interior side of the long wall 25 or may be integrated into the interior side of the long wall 25 in order to locally increase the friction of the air flow at such structure 27.
In the shown example, the straightening section 24 is formed as a straight tube with a constant diameter. For example the straightening section 24 may have a length of approximately 30 mm and diameter of 110 mm, giving value of ratio between length and dimeter higher than 0.2. Thus, the fan wheel 12 receives straightened airflow and its efficiency is higher and its energy consumption is lower compared to an assembly 10 without the straightening section 24. The shown example, the straightening section 24 or straightening segment may be positioned in a back air duct component and the rest of the assembly 10 is positioned inside a bottom group of the appliance.
Due to the reduction or change of the cross section between the fan wheel 12 and the heat exchanger 30, an uneven velocity distribution is formed at the entrance to the fan wheel 12. By providing the straightening section 24, the air flow may be straightened and the standard deviation of the velocity distribution may be reduced. Thus, the more even or smooth air velocity distribution inside the air channel cross-section before entering the fan wheel results in higher efficiency and lower energy consumption.

List of reference signs

10: - assembly
11: - process air channel
12: - fan wheel
13: - motor

20: - air nozzle
21: - outlet opening
22: - inlet opening
23: - funnel-shaped tube section
24: - straightening section
25: - long wall
26: - short wall
27: - structure

30: - heat exchanger

D: - flow direction

Claims

Assembly (10) for an appliance, comprising a process air channel (11), an air nozzle (20), at least one heat exchanger (30) and a fan wheel (12), wherein the process air channel (11) connects the heat exchanger (30) with the fan wheel (12), wherein the air nozzle (20) comprises an inlet opening (22) to collect tempered air from the heat exchanger (30), a funnel-shaped tube section (23) and an outlet opening (21) to guide a collected air flow to the fan wheel (12), wherein the air nozzle (20) comprises a straightening section (24) in flow direction (D) of the air, prior to the outlet opening (21).
Assembly of claim 1, wherein the straightening section (24) is formed as a straight tube with constant or variable diameter, or wherein at least a part of the straightening section (24) is formed with an angle or a curve, and/or wherein the straightening section (24) is aligned in an angle of 90° or less relative to a rotation axis of the fan wheel (12).
Assembly of claim 1 or 2, wherein the air nozzle (20) comprises a cross-section with a symmetrical or asymmetrical shape.
Assembly of anyone of the previous claims, wherein the funnel-shaped tube section (23) of the air nozzle (20) comprises curved and/or straight shaped walls that reduces a cross section of the air nozzle (20) starting from the inlet opening (22) to the straightening section (24) of the air nozzle (20).
Assembly of anyone of the previous claims, wherein the straightening section (24) of the air nozzle (20) comprises a ratio of length of the straightening section (24) to diameter of an outlet opening (21) of the straightening section (24) of 0.2 or more.
Assembly of anyone of the previous claims, wherein the straightening section (24) and/or the funnel-shaped tube section (23) at least locally arranged comprises guiding ribs and/or at least one grid and/or at least one wall structure (27) formed inside the air nozzle (20).
Assembly of anyone of the previous claims, wherein the funnel-shaped tube section (23) is formed asymmetrically and at least partially comprises at least one long wall (25) and at least one short wall (26), wherein at least one wall structure (27) is attached at or integrated into the long wall (25), wherein the long wall (25) comprises a length larger than a length of the short wall (26).
Assembly of anyone of the previous claims, wherein the straightening section (24) and the funnel-shaped tube section (23) of the air nozzle (20) are integrally formed, or wherein the straightening section (24) and the funnel-shaped tube section (23) are detachably connected with each other.
Air nozzle (20) for an appliance, comprising an inlet opening (22), that is configured to collect tempered air from a heat exchanger (30), comprising a funnel-shaped tube section (23) and comprising an outlet opening (21), that is configured to guide a collected air flow to a fan wheel (12), wherein the air nozzle (20) comprises a straightening section (24) which is connecting the outlet opening (21) with the funnel-shaped tube section (23).
Appliance, comprising an assembly (10) of anyone of the claims 1 to 8.