Manufacturing Vacuum Cleaners

TECHNICAL FIELD

The present invention relates to a vacuum cleaner. Further, the present invention relates to a set of at least two vacuum cleaners. Moreover, the present invention relates to a method of manufacturing a set of at least two vacuum cleaners.

BACKGROUND

A particular category of vacuum cleaners are vacuum cleaners comprising a cyclone separator. The cyclone separator is utilised for separating dust and debris from a dust and debris containing airflow. The cyclone separator comprises a cylindrical and/or frustoconical chamber. An air inlet of the cyclone separator is arranged to produce a substantially tangentially directed airflow into the chamber. An air outlet from the chamber is arranged centrally on a centre axis of the chamber. A suction producing unit of the vacuum cleaner produces an airflow through the chamber. Due to the tangentially directed air inlet, the air flowing into the chamber creates a vortex inside the chamber. Dust and debris contained in the inflowing air is thus, propelled outwardly towards an inner circumferential wall of the chamber. Air relieved of dust and debris flows out of the chamber through the centrally arranged air outlet. In one kind of cyclone separator there is provided a separate outlet for dust and debris leading to a receptacle for dust and debris. The receptacle is emptied from time to time. In a different kind of cyclone separator the separated dust and debris remain in the cylindrical and/or frustoconical chamber, which accordingly has to be emptied from time to time.

In a vacuum cleaner comprising a cyclone separator, the diameter of the chamber and an area of the air inlet together with the flow rate of air flowing through the chamber determine the speed of the vortex inside the chamber. The vortex affects dust and debris separation efficiency of the cyclone separator. Furthermore, a too low or too high airflow does not create any usable vortex inside the chamber. Thus, a particular cyclone separator is operable within a certain air flow rate range.

Vacuum cleaners are labelled according to their energy consumption levels. In a vacuum cleaner with low energy consumption a lower powered suction producing unit is used than in a vacuum cleaner with high energy consumption. Naturally, a high powered suction producing unit may produce a higher flow rate of air than a low powered suction producing unit. Accordingly, when constructing a vacuum cleaner comprising a cyclone separator, various design parameters have to be considered. The cyclone separator of a vacuum cleaner has to be adapted to the specific suction producing unit used in the vacuum cleaner. Also, for the same flow rate of air, a small air inlet area of the cyclone separator creates a faster vortex inside the chamber of the cyclone separator than a large air inlet area of the cyclone separator. However, a faster vortex entails a higher noise level of the vacuum cleaner. Thus, in a vacuum cleaner of a particular energy consumption level either cleaning efficiency or noise level may be prioritised. SUMMARY

It is an object of the present invention to facilitate tuning of cyclone separators of vacuum cleaners.

According to an aspect of the invention, the object is achieved by a vacuum cleaner comprising a cyclone separator and a suction producing unit, the cyclone separator comprising a cylindrical and/or frustoconical chamber with a substantially tangentially directed air inlet and a centrally arranged air outlet. The suction producing unit is arranged in fluid communication with the air outlet and is configured to draw air through the cyclone separator from the air inlet to the air outlet. The cyclone separator at the air inlet comprises an arc-shaped wall portion forming part of an inner surface of the chamber. The cyclone separator comprises at least a first housing part and a second housing part forming the chamber and the air inlet. A first wall portion adjacent a first circumferential end of the arc- shaped wall portion at the air inlet is formed by the first housing part, and a second wall portion of the arc-shaped wall portion is formed by the second housing part.

Due to the arc-shaped wall portion being formed by at least two separate housing parts, different length arc-shaped wall portions may be provided in the vacuum cleaner by exchanging only the first housing part. Thus, by only exchanging the first housing part comprising the first wall portion with a different first housing part having a differently sized first wall portion, the cyclone separator is tuneable to alter at least one vacuum cleaner characteristic. Accordingly, a vacuum cleaner characteristic such as separation efficiency and/or noise level are easily changed. As a result, the above mentioned object is achieved.

During use of the vacuum cleaner the cyclone separator is utilised for separating dust and debris from a dust and debris containing airflow. The air inlet being substantially tangentially directed entails that inflowing air into the chamber is directed from the air inlet along the inner surface of the chamber. The cyclone separator comprising a cylindrical and/or frustoconical chamber entails that at least a portion of the inner surface of the chamber is substantially cylindrical and/or substantially frustoconical. In the cylindrical and/or frustoconical chamber of the cyclone separator a vortex is formed by the air being draw into the chamber through the air inlet. Accordingly, the arc-shaped wall portion forms part of the inner surface. Dust and debris contained in the air is propelled outwardly towards the inner surface of the chamber by the vortex. Air relieved of dust and debris flows out of the chamber through the centrally arranged air outlet. The suction producing unit may comprise a fan and an electric motor.

Suitably, the first housing part is substantially smaller than the second housing part. Such a smaller first housing part is substantially cheaper to manufacture in different versions than one large housing part which includes the entire arc-shaped wall portion. Such a large housing part would have to be manufactured in different versions with differently formed arc- shaped wall portions to provide different vacuum cleaning characteristics. Thus, vacuum cleaners with different suction and/or dust separation characteristics may be provided at low cost by using different kinds of first housing parts in different vacuum cleaners.

According to embodiments, the first housing part may form at least a portion of the air inlet. In this manner the first wall portion may be provided together with at least a portion of the air inlet. Thus, different first housing parts may provide differently sizes air inlets, e.g. for adapting the cyclone separator to different suction producing units.

According to embodiments, a resilient sealing may arranged between the first housing part and the second housing part. In this manner an air tight seal between the first and second housing parts may be ensured. Thus, the air flowing into the chamber may not be disturbed by any air leaking into the air inlet.

According to embodiments, the vacuum cleaner may comprise a receptacle for dust and debris, wherein the cyclone separator may comprise an outlet for dust and debris arranged at an end of the chamber opposite to the air inlet, the outlet for dust and debris being arranged in communication with the receptacle for dust and debris. In this manner dust and debris may be collected in a receptacle, which is separate from the chamber of the cyclone separator. Thus, the efficiency of the cyclone separator is not reduced by dust and debris accumulating over time in the chamber of the cyclone separator. According to a further aspect of the invention, the above-mentioned object is achieved by a set of at least two vacuum cleaners comprising a first vacuum cleaner and a second vacuum cleaner. Each of the first and second vacuum cleaners comprises a cyclone separator and a suction producing unit. The cyclone separator comprises a cylindrical and/or frustoconical chamber with a substantially tangentially directed air inlet and a centrally arranged air outlet. The suction producing unit is arranged in fluid communication with the air outlet and is configured to draw air through the cyclone separator from the air inlet to the air outlet. The cyclone separator at the air inlet comprises an arc-shaped wall portion forming part of an inner surface of the chamber. Each of the cyclone separators of the first and second vacuum cleaners comprises at least a first housing part and a second housing part forming the respective chambers and air inlets. In at least the first vacuum cleaner a first wall portion adjacent a first circumferential end of the arc-shaped wall portion at the air inlet is formed by the first housing part. In each of the first and second vacuum cleaners a second wall portion of the arc-shaped wall portion is formed by the second housing part. The second housing parts of the first and second vacuum cleaners are identical. The first wall portion of the first housing part of the first vacuum cleaner has a larger area than any first wall portion of the first housing part of the second vacuum cleaner such that the air inlet of the cyclone separator of the first vacuum cleaner has a smaller area than the air inlet of the cyclone separator of the second vacuum cleaner.

Due to the arc-shaped wall portion being formed by at least two separate housing parts, different length arc-shaped wall portions are provided in the cyclone separators of the first and second vacuum cleaners by the use of different first housing parts in the first and second vacuum cleaners, the first housing parts comprising first wall portions of different sizes, or the first housing part of the first vacuum cleaner comprising a first wall portion while the first housing part of the second vacuum cleaner does not comprise any first wall portion, whereas other parts, such as the second housing parts of the cyclone separators, are identical.

Accordingly, different vacuum cleaner characteristics, such as different separation efficiencies and/or different noise levels, are easily achieved in the first and second vacuum cleaners by tuning the first and second vacuum cleaners with different first housing parts. Alternatively, or additionally, the cyclone separators of the first and second vacuum cleaners are tuned to different vacuum cleaner characteristics such as suction producing unit power, conduit system dimensions, etc. by being provided with different first housing parts. As a result, the above mentioned object is achieved.

Different vacuum cleaner characteristics may entail that the first and second vacuum cleaners have different energy consumption levels, which may entail that suction producing units of different power ratings are used in the first and second vacuum cleaners. Thus, the air speed in the vortex formed in the chamber may be tuned to the air flow rate through the chamber provided by the relevant suction producing unit of the first and second vacuum cleaners by the provision of the air inlets having different areas through the use of different first housing parts in the first and second vacuum cleaners.

It has been realized by the inventor that the same size of chamber may be used in cyclone separators of vacuum cleaners comprising differently powered suction producing units, and that it is sufficient to provide differently sized inlet areas of the air inlet, only through the use of different first housing parts, to tune a cyclone separator to be used with differently powered suction producing units. By providing an adequately sized air inlet for a particularly powered suction producing unit, a suitable vortex is formed in the chamber.

According to embodiments, the first vacuum cleaner may be a vacuum cleaner according to any one aspect and/or embodiment discussed herein and the second vacuum cleaner is a vacuum cleaner according to any aspect and/or embodiment discussed herein. According to a further aspect of the invention, the above mentioned object is achieved by a method of manufacturing a set of at least two vacuum cleaners comprising a first and a second vacuum cleaner, each of the first and second vacuum cleaners comprising a cyclone separator and a suction producing unit. The cyclone separator comprising a cylindrical and/or frustoconical chamber with a substantially tangentially directed air inlet and a centrally arranged air outlet. The suction producing unit is arranged in fluid communication with the air outlet and is configured to draw air through the cyclone separator from the air inlet to the air outlet. The cyclone separator at the air inlet comprises an arc-shaped wall portion forming part of an inner surface of the chamber. Each of the cyclone separators of the first and second vacuum cleaners comprises at least a first housing part and a second housing part forming the respective chambers and air inlets. In at least the first vacuum cleaner a first wall portion adjacent a first circumferential end of the arc-shaped wall portion at the air inlet is formed by the first housing part. In each of the first and second vacuum cleaners a second wall portion of the arc-shaped wall portion is formed by the second housing part.

The method comprises:

- installing identical second housing parts in the first and second vacuum cleaners,

- installing a first housing part with the first wall portion having a first area in the first vacuum cleaner, and

- installing a first housing part with a first wall portion having a second area, or being devoid of any first wall portion, in the second vacuum cleaner, wherein

the first wall portion of the first housing part of the first vacuum cleaner is larger than any first wall portion of the first housing part of the second vacuum cleaner such that the air inlet of the first vacuum cleaner has a smaller area than the air inlet of the second vacuum cleaner. Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the invention, including its particular features and advantages, will be readily understood from the example embodiments discussed in the following detailed description and the accompanying drawings, in which :

Fig. 1 a illustrates a vacuum cleaner according to embodiments,

Fig. 1 b illustrates a set of at least two vacuum cleaners according to embodiments, Fig. 2 illustrates an exploded view of a cyclone separator according to embodiments, Figs. 3, 4a and 4b illustrate cross sections through the cyclone separator of Fig. 2,

Fig. 4c illustrates a cross section through a cyclone separator, and

Fig. 5 illustrates a method of manufacturing a set of at least two vacuum cleaners. DETAILED DESCRIPTION

Aspects of the present invention will now be described more fully. Like numbers refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and/or clarity. Fig. 1 a illustrates a vacuum cleaner 2 according to embodiments. The vacuum cleaner 2 comprises a cyclone separator 4, a suction producing unit 6 (schematically illustrated), and a receptacle 8 for dust and debris. The cyclone separator 4 comprises a cylindrical chamber with an air inlet as will be discussed further below, inter alia with reference to Figs. 3, 4a, and 4b. The cyclone separator 4 comprises at least a first housing part and a second housing part forming the chamber and the air inlet. The receptacle 8 is arranged in open connection with the chamber of the cyclone separator 4 for receiving dust and debris separated in the cyclone separator 4.

According to some embodiments, the suction producing unit 6 may comprise an electric motor and a fan, wherein the electric motor has a power consumption within a range of 400 - 2000 W.

Fig. 1 b illustrates a set of at least two vacuum cleaners according to embodiments. The set of vacuum cleaners comprises a first vacuum cleaner 2 and a second vacuum cleaner 2'. The first and second vacuum cleaners 2, 2' are both vacuum cleaners comprising cyclone separators 4, 4' of the same kind as the vacuum cleaner 2 discussed in connection with Fig. 1 a. The first and second vacuum cleaners 2, 2' have different vacuum cleaner characteristics, and thus, differ from each other in at least one aspect. Mentioned purely as an example, the electric motors of the suction producing units of the first and second vacuum cleaners 2, 2' may have electric motors with different power ratings, the first and second vacuum cleaners 2, 2' may be designed for different air flow rates, the cyclone separators 4, 4' of the first and second vacuum cleaners 2, 2' may be designed for different vortex speeds, the conduit systems in the first and second vacuum cleaners 2, 2' may have different dimensions, the noise levels of the first and second vacuum cleaners 2, 2' may be different, etc. The second housing parts of the cyclone separators of the first and second vacuum cleaners 2, 2' are identical, whereas the first housing part of the cyclone separator of the first vacuum cleaners 2 differs from the first housing part of the cyclone separator of the second vacuum cleaners 2'. Thus, the cyclone separators 4, 4' of each of the first and second vacuum cleaners 2, 2' may be tuned to vacuum cleaner characteristics of the first and second vacuum cleaners 2, 2', and/or the cyclone separators 4, 4' of each of the first and second vacuum cleaners 2, 2' may tune the first and second vacuum cleaners 2, 2' to provide different vacuum cleaner characteristics in the first and second vacuum cleaners 2, 2'.

The following description, referring to a cyclone separator of a vacuum cleaner, applies to the cyclone separators of each of the first and second vacuum cleaners 2, 2'. Accordingly, the first vacuum cleaner 2 may be a vacuum cleaner according to any one aspect and/or embodiment discussed herein and the second vacuum cleaner 2' may be a vacuum cleaner according to any aspect and/or embodiment discussed herein. Fig. 2 illustrates an exploded view of a cyclone separator 4 according to embodiments. The cyclone separator 4 may be used in a vacuum cleaner of the canister type as disclosed in Figs. 1 a and 1 b, or in a different kind of vacuum cleaner such a vacuum cleaner of the stick type, or of the upright type. The cyclone separator 4 comprises a cylindrical chamber 10 with a substantially tangentially directed air inlet 12 and a centrally arranged air outlet. A suction producing unit 6 of a related vacuum cleaner is arranged in fluid communication with the air outlet and is configured to draw air through the cylindrical chamber 10 of the cyclone separator 4, from the air inlet 12 to the air outlet. The cyclone separator 4 comprises at least a first housing part 14 and a second housing part 16 forming the chamber 10 and the air inlet 12. The receptacle 8 for dust and debris is connected to the chamber 10. According to some embodiments, at least one portion of the chamber 10 may have a diameter within a range of 30 - 250 mm, preferably within a range of 30 - 160 mm, more preferably within a range of 70 - 120 mm, and wherein the suction producing unit 6 may produce an airflow of up to 40 litres/second through the cyclone separator 4.

The air inlet 12 has a cross sectional area extending perpendicularly to the air flow into the chamber 10, see Fig. 4b. The first housing part 14 forms a portion of the air inlet 12, see Figs. 4a and 4b. By using different first housing parts 14 different cross sectional areas of the air inlet 12 may be provided in combination with the second housing part 16. Thus, the cyclone separator 4 may be tuned. The first housing part 14, which forms a portion of the air inlet 12, is substantially smaller than the second housing part 16. A resilient sealing 17 is arranged between the first housing part 14 and the second housing part 16. The resilient sealing 17 may be formed by e.g. an extruded round sealing or a lip sealing. The resilient sealing 17 may be made e.g. from rubber or from a thermoplastic elastomer.

Fig. 3 illustrates a cross section through the cyclone separator 4 of Fig. 2. The cylindrical chamber 10 extends in an axial direction 18. During use of the cyclone separator 4, as the suction producing unit 6 draws air through the cyclone separator 4, the air inlet 12 directs inflowing air containing dust and debris in a tangential direction at an axial end of the cylindrical chamber 10 to form a vortex 22 along the inner surface of the chamber 10, as indicated by the arrows in the Fig. 3. The cyclone separator 4 comprises an outlet 24 for dust and debris arranged at an axial end of the chamber 10 opposite to the air inlet 12. The outlet 24 for dust and debris is arranged in communication with the receptacle 8 for dust and debris. Thus, dust and debris is collected in the receptacle 8. The air, relieved from dust and debris flows out of the chamber 10 through the centrally arranged air outlet 20. The receptacle 8 may be separated from the cyclone separator 4 and the relevant vacuum cleaner to be emptying from collected dust and debris.

In alternative embodiments, the chamber 10 may comprise a frustoconical section, as indicated with broken lines 25 in Fig. 3. Alternatively, the entire chamber 10 may be frustoconically shaped, or the chamber 10 may comprise two frustoconical sections.

Figs. 4a and 4b illustrate cross sections through the cyclone separator 4 illustrated in Figs. 2 and 3, along line IV - IV shown in Fig. 3.

At the air inlet 12, the cyclone separator 4 comprises an arc-shaped wall portion 26 forming part of the substantially cylindrical inner surface of the cylindrical chamber 10. As discussed above, the cyclone separator 4 comprises a first housing part 14 and a second housing part 16. The first and second housing parts 14, 16 form at least part of the chamber 10 and the air inlet 12. A first wall portion 28 of the arc-shaped wall portion 26 is formed by the first housing part 14. The first wall portion 28 is arranged adjacent a first circumferential end 30 of the arc- shaped wall portion 26. The first wall portion 28 is arranged at the air inlet 12, i.e. the first circumferential end 30 is arranged adjacent the air inlet 12.

A second wall portion 32 of the arc-shaped wall portion 26 is formed by the second housing part 16. The first wall portion 28 is arranged adjacent to the second wall portion 32.

The second wall portion 32 extends from the first wall portion 28 to a second circumferential end 34 of the arc-shaped wall portion 26 at the air inlet 12. The second circumferential end 34 is arranged at an end of the arc-shaped wall portion 26 opposite to the first circumferential end 30.

The first wall portion 28 extends from the air inlet 12 in a direction opposite to a rotation direction of a vortex 22 formed in the chamber 10 during use of a relevant vacuum cleaner.

A position of the air inlet 12 in relation to the cylindrical chamber 10, is defined by the first circumferential end 30 of the first wall portion 28. For the purpose of defining a cross sectional area of the air inlet 12, the cross sectional area of the air inlet 12 is measured at an angle to the first circumferential end 30, which provides the smallest area. In the illustrated embodiments, the air inlet 12 extends approximately perpendicularly to an air inlet direction 36, which is schematically illustrated with an arrow in Fig. 4b. That is, the air flowing into the chamber 10 via the air inlet 12 flows along the air inlet direction 36. The cross sectional area of the air inlet 12 is indicated with a broken line 38 in Fig. 4b, and extends perpendicularly to the plane of Fig. 4b. Accordingly, the first housing part 14, at the first circumferential end 30 of the arc-shaped wall portion 26, delimits the air inlet 12. The second housing part 16, at the second circumferential end 34 of the arc-shaped wall portion 26, delimits the air inlet 12. In the axial direction of the chamber 10 the air inlet 12 may be delimited by the first and/or second housing parts 14, 16.

A tangent 40 of the first wall portion 28, at the first circumferential end 30 extends at an angle a of less than 90 degrees to the air inlet direction 36 into the chamber 10 from the air inlet 12 during use of the vacuum cleaner. Fig. 4c illustrates a cross section through a cyclone separator 4 corresponding to the cross section shown in Fig. 4b. The cyclone separator 4 in the embodiments of Fig. 4c corresponds in much to the cyclone separator 4 of the embodiments illustrated in Fig. 4b. In particular, the second housing part 16 of the embodiments of Fig. 4b is identical with the second housing part 16 of the embodiments of Fig. 4c. However, the respective first housing parts 16 of the embodiments of Figs. 4b and 4c differ from each other in one aspect. In the embodiments of Fig. 4b the first wall portion 28 of the first housing part 14 has a larger area than the first wall portion 28' of the first housing part 14 of the embodiments of Fig. 4c. Accordingly, the air inlet 12 of the cyclone separator 4 of the embodiments of Fig. 4b has a smaller area than the air inlet 12' of the cyclone separator 4 of the embodiments of Fig. 4c. Since, each first housing part 14, 14' forms at least a portion of the air inlet 12, 12', and the first wall portion 28, 28', differently sized air inlets 12, 12' may be provided in the cyclone separators 4, 4' simply by the use of different first housing parts 14, 14', in order to tune a relevant cyclone separator 4, 4'.

In these embodiments, the first wall portions 28, 28' of the two first housing parts 14, 14' have different circumferential lengths to provide the differently sized air inlets 12, 12'. In alternative embodiments, the first wall portion may additionally, or alternatively, extend over different lengths in the axial direction of the cyclone separation 4 to provide differently sized air inlets in different first housing parts 14.

Referring back to Fig. 1 b and the set of at least two vacuum cleaners illustrated therein, the first vacuum cleaner 2 may comprise a cyclone separator 4 provided with a first housing part 14 as illustrated in Fig. 4b, and the second vacuum cleaner 2' may comprise a cyclone separator 4' provided with a first housing part 14' as illustrated in Fig. 4c. Thus, a set of at least two vacuum cleaners comprising a first vacuum cleaner 2 and a second vacuum cleaner 2', wherein the first and second vacuum cleaners 2, 2' have different vacuum cleaner characteristics is easily achieved by the use of the different first housing parts 14, 14'. Thus, with reference to Fig. 1 b, 4b, and 4c, in such a set of at least two vacuum cleaners each of the first and second vacuum cleaners 2, 2' comprises a cyclone separator 4, 4' and a suction producing unit. The cyclone separator 4, 4' comprises a cylindrical and/or frustoconical chamber 10 with a substantially tangentially directed air inlet 12 and a centrally arranged air outlet 20. The suction producing unit is arranged in fluid communication with the air outlet 20 and is configured to draw air through the cyclone separator 4, 4' from the air inlet 12 to the air outlet 20. The cyclone separator 4, 4' at the air inlet 12 comprises an arc-shaped wall portion forming part of an inner surface of the chamber 10. Each of the cyclone separators 4, 4' of the first and second vacuum cleaners 2, 2' comprises at least a first housing part 14, 14' and a second housing part forming the respective chambers 10 and air inlets 12, 12'. In at least the first vacuum cleaner 2 a first wall portion 28 adjacent a first circumferential end 30 of the arc-shaped wall portion at the air inlet 12 is formed by the first housing part 14. In each of the first and second vacuum cleaners 2, 2' a second wall portion 32 of the arc-shaped wall portion is formed by the second housing part 16. The second housing parts 16 of the first and second vacuum cleaners 2, 2' are identical. The first wall portion 28 of the first housing part 14 of the first vacuum cleaner 2 has a larger area than any first wall portion 28' of the first housing part 14' of the second vacuum cleaner 2' such that the air inlet 12 of the cyclone separator 4 of the first vacuum cleaner 2 has a smaller area than the air inlet 12' of the cyclone separator 4' of the second vacuum cleaner 2'.

According to some embodiments, the first housing part 14' of the second vacuum cleaner does not comprise any first wall portion.

According to some embodiments, the suction producing unit of the first vacuum cleaner 2 may have a lower power rating than the suction producing unit of the second vacuum cleaner 2'. Due to the differently sized air inlets 12, 12' of the first and second vacuum cleaners 2, 2' the respective cyclone separators 4, 4' may be tuned to the respective suction producing units.

Fig. 5 illustrates a method 100 of manufacturing a set of at least two vacuum cleaners. The set of at least two vacuum cleaners may be a set comprising a first and a second vacuum cleaner as illustrated in Fig. 1 b. As discussed above, each of the first and second vacuum cleaners comprises a cyclone separator and a suction producing unit. The cyclone separator comprises a cylindrical and/or frustoconical chamber with a substantially tangentially directed air inlet and a centrally arranged air outlet. The suction producing unit is arranged in fluid communication with the air outlet and is configured to draw air through the cyclone separator from the air inlet to the air outlet. The cyclone separator at the air inlet comprises an arc- shaped wall portion forming part of an inner surface of the chamber. Each of the cyclone separators of the first and second vacuum cleaners comprises at least a first housing part and a second housing part forming the respective chambers and air inlets. In at least the first vacuum cleaner a first wall portion adjacent a first circumferential end of the arc-shaped wall portion at the air inlet is formed by the first housing part. In each of the first and second vacuum cleaners a second wall portion of the arc-shaped wall portion is formed by the second housing part.

The method comprises: - installing 102 identical second housing parts in the first and second vacuum cleaners,

- installing 104 a first housing part with the first wall portion having a first area in the first vacuum cleaner, and

- installing 106 a first housing part with a first wall portion having a second area, or being devoid of any first wall portion, in the second vacuum cleaner, wherein

the first wall portion of the first housing part of the first vacuum cleaner is larger than any first wall portion of the first housing part of the second vacuum cleaner such that the air inlet of the first vacuum cleaner has a smaller area than the air inlet of the second vacuum cleaner. This invention should not be construed as limited to the embodiments set forth herein. A person skilled in the art will realize that different features of the embodiments disclosed herein may be combined to create embodiments other than those described herein, without departing from the scope of the present invention, as defined by the appended claims.

Although the invention has been described with reference to example embodiments, many different alterations, modifications and the like will become apparent for those skilled in the art. The vacuum cleaner may comprise a cyclone separator wherein the separated dust and debris remains in the cylindrical and/or frustoconical chamber, which accordingly has to be emptied from time to time. Therefore, it is to be understood that the foregoing is illustrative of various example embodiments and that the invention is defined only by the appended claims.

As used herein, the term "comprising" or "comprises" is open-ended, and includes one or more stated features, elements, steps, components or functions but does not preclude the presence or addition of one or more other features, elements, steps, components, functions or groups thereof.