WO2019120544A1

WO2019120544A1 - Air-cleaning appliance comprising disc stack separator

Info

Publication number: WO2019120544A1
Application number: PCT/EP2017/084098
Authority: WO
Inventors: Johann Zita; Henrik Holm; Johan SPÅNG
Original assignee: Aktiebolaget Electrolux
Priority date: 2017-12-21
Filing date: 2017-12-21
Publication date: 2019-06-27
Also published as: EP3727119A1; CN111417332B; CN111417332A

Abstract

The invention relates to an appliance for cleaning an airflow comprising a dust separator (10), which dust separator (10) comprises a dust separation chamber (11) comprising an air inlet (12) where an airflow to be cleaned enters the dust separation chamber (11); an air outlet (13) where the cleaned airflow exits the dust separation chamber (11); a shaft (14) arranged along a longitudinal axis of the dust separation chamber (11); and a plurality of spaced apart disc members (15) arranged along the shaft (14), the shaft (14) being arranged to rotate the disc members (15) in order to cause a centrifugal force which transports particles contained in the airflow entering the air inlet (12) towards an inner wall of the dust separation chamber (11), while causing the airflow to move towards a centre of the spaced apart disc members (15) for travelling towards the air outlet (13) and exit the dust separation chamber (11).

Description

AIR-CLEANING APPLIANCE COMPRISING DISC STACK

SEPARATOR

TECHNICAL FIELD

The invention relates to an appliance for cleaning an airflow comprising a dust separator.

BACKGROUND

In prior art appliances for cleaning an airflow, e.g. vacuum cleaners, a number of different technologies are available for separating debris and dust from a dirty airflow entering an air inlet in order to exhaust a clean airflow via an air outlet. These technologies include e.g. utilizing a disposable dust bag that allows air to pass through it but which traps most of the dust and debris, using a container and a filter instead of the dust bag (“bagless”), or cyclonic separation where dirty air goes into a cyclone chamber inlet, and dirt particles are accelerated up to a very high rotational speed and thrown against an inner wall of the cyclone chamber and falls down to a separate dust container, while the cleaned air follows an inner airflow vortex and exits the cyclone chamber via an air outlet.

Since there is an ever increasing desire to improve cleaning performance in vacuum cleaners, there is consequently a desire to improve the dust separation process.

SUMMARY

An object of the invention is to solve, or at least mitigate, this problem in the art and thus provide an improved dust separator for an air-cleaning appliance.

This object is attained by an appliance configured to clean an airflow comprising a dust separator, which dust separator comprises a dust separation chamber comprising, an air inlet where an airflow to be cleaned enters the dust separation chamber, an air outlet where the cleaned airflow exits the dust separation chamber, a shaft arranged along a longitudinal axis of the dust separation chamber, and a plurality of spaced apart disc members arranged along the shaft, the shaft being arranged to rotate the disc members in order to cause a centrifugal force which transports particles contained in the airflow entering the air inlet towards an inner wall of the dust separation chamber, while causing the airflow to move towards a centre of the spaced apart disc members for travelling towards the air outlet and exit the dust separation chamber.

Hence, the centrifugal force created by the rotating disc members will cause cleaned air to exit the air outlet while dust and debris collides with the inner wall of the dust separation chamber and fall towards a bottom section of the chamber by means of gravity.

The dust separator is typically referred to as a disc stack separator, a disc bowl centrifuge or a conical plate centrifuge.

Advantageously, the inventors have discovered that the disc separator when implemented in an appliance such as a vacuum cleaner is more energy- efficient as compared to a cyclonic separator for attaining the same

separation performance.

With the dust separator according to an embodiment, the dust separation will advantageously be improved, and any filter(s) located downstream of the dust separator - which typically are present in the case of a vacuum cleaner - will not be clogged, and a user will thus not have to manually clean these filters.

In an embodiment, the dust separation chamber is arranged with one or more openings in a section of the chamber where one of the disc members faces the air outlet, wherein air is entered into the dust separation chamber via the openings in order to counter an airflow flowing from the air inlet, via a bypass path created between said one of the disc members and the section, to the air outlet. In a vacuum cleaner, the dust separator is at negative pressure relative to the atmosphere, which negative pressure is created by a motor fan. This has as an effect that air will flow through the openings and thus advantageously counter any air flowing in the bypass path. As a result, dust and debris entering the chamber via the air inlet will eventually contact the disc members and be transported towards the inner wall of the chamber by the centrifugal force caused by the rotating disc members. Advantageously, this will increase the particle-separation performance of the dust separator while decreasing the energy required to rotate the shaft, as compared to a solution where for instance a an annular flange is used to seal the bypass path.

In an embodiment, a top section of the dust separation chamber is removably attached to a main body of the chamber.

In a further embodiment, the air inlet and the air outlet being arranged such that the airflow entering the air inlet is substantially perpendicular to the airflow exiting the dust separation chamber via the air outlet.

In another embodiment, the air outlet is aligned with a longitudinal axis of the dust separation chamber extending at the centre of the plurality of disc members.

In yet another embodiment, the dust separator further comprises a motor arranged to be in connection with the shaft for rotating the shaft and the disc members.

In still another embodiment, the shaft is arranged to extend longitudinally inside the air outlet.

In an embodiment, the dust separator further comprises at least one bearing arranged around the shaft and is further arranged to be held in place by bearing brackets attached to an inner wall of the air outlet. In yet an embodiment, the dust separator further comprises a further air inlet arranged along a periphery of the shaft inside the air outlet and ending at the bearing, via which air advantageously is entered in order to clean the bearing.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the element, apparatus, component, means, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now described, by way of example, with reference to the accompanying drawings, in which: Figure 1 illustrates a cross-sectional view of a dust separator according to an embodiment;

Figure 2 illustrates a vacuum cleaner in perspective view, in which the dust separator may be implemented according to an embodiment;

Figure 3 illustrates a cross-sectional view of an upright vacuum cleaner of the type shown in Figure 2, in which the dust separator is implemented according to an embodiment;

Figure 4a illustrates a cross-sectional view of the dust separator according to another embodiment;

Figure 4b illustrates the dust separator of Figure 4a, with a top section removed;

Figure 5 illustrates a top view of the dust separator of Figure 4a; Figure 6 illustrates a cross-sectional view of the dust separator according to a further embodiment; and

Figure 7 illustrates a top view of the dust separator of Figure 6.

DETAILED DESCRIPTION

The invention will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown. This 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 by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout the description.

Figure 1 illustrates a cross-sectional view of a dust separator 10 according to an embodiment, to be implemented in an appliance for cleaning an air flow, such as a vacuum cleaner or an air cleaner.

It should be noted that the dust separator 10 may be a part of a separation system comprising e.g., a cyclonic pre-separator for separating larger particles before the airflow to be cleaned is passed through a mesh filter and enters the dust separator 10. Further, one or more post-filters may be used after the dust separator 10. However, in the following, the dust separator 10 will be discussed.

By providing the dust separator 10 according to an embodiment, the dust separation will advantageously be improved, and filter(s) located

downstream of the dust separator 10 will not be clogged, and a user will thus not have to manually clean these filters.

The dust separator 10 comprises a dust separation chamber 11 having an air inlet 12 where an airflow to be cleaned enters the dust separation chamber 11, and an air outlet 13 where the cleaned airflow exits the dust separation chamber 11.

Further, the dust separator 10 comprises a shaft 14 arranged along a longitudinal axis of the dust separation chamber 11, and a plurality of spaced apart disc members 15 arranged along the shaft 14.

The shaft 14 is typically rotated by a motor (not shown) which in its turn rotates the disc members 15 in order to cause a centrifugal force which transports particles - i.e. dust and debris - contained in the airflow entering the air inlet 12 towards an inner wall of the dust separation chamber 11, while causing the airflow to travel towards a centre of the spaced apart disc members 15 for travelling in an upwards direction along the shaft 14 towards the air outlet 13 for exiting the dust separation chamber 11.

Smaller particles will follow the airflow in between the disc members but will due to a high G-force caused by the rotation move towards a periphery of the disc members and then be centrifuged out of the disc members.

Hence, the centrifugal force created by the rotating disc members 15 will cause cleaned air to exit the air outlet 13 aligned with the centre of the spaced apart disc members 15 while dust and debris collides with the inner wall of the dust separation chamber 11 and fall towards a bottom section of the chamber 11 by means of gravity.

The dust separator 10 illustrated in Figure 1 is typically referred to as a disc stack separator, a disc bowl centrifuge or a conical plate centrifuge.

Advantageously, the inventors have discovered that the disc separator 10 illustrated with reference to Figure 1 is more energy-efficient as compared to a cyclonic separator for attaining the same separation performance and is further smaller in size.

Figure 2 illustrates a vacuum cleaner 1 in perspective view, in which the dust separator 10 may be implemented according to an embodiment. This particular type of vacuum cleaner is known as an upright cleaner or stick cleaner. The vacuum cleaner may be powered by a chargeable battery, an electric cable or a combination of the two.

The vacuum cleaner 1 comprises a housing 2. The housing 2 may be made as a hollow body or structure for housing some parts of the vacuum cleaner 1, such as the dust separator of Figure 1.

The housing 2 may comprise a motor fan for generating airflow. A schematic airflow and a schematic motor fan are illustrated in Figure 3. The housing 2 also comprises the air outlet 13 of the dust separator and a housing air inlet, also illustrated in Figure 3.

The vacuum cleaner 1 further comprises a profile 3 to which the housing 2 is attached. The profile 3 may be of a telescopic type such that the length of the profile 3 can be adjusted.

The profile 3 extends between a nozzle 4 in one end and a handle 5 in the other to be held by a user for moving the vacuum cleaner over a surface to be cleaned. The handle 5 may optionally comprise a control arrangement 51, e.g. a push button or a slider, for control of at least one of a fan effect, a nozzle function or any other vacuum cleaner function which may need to be adjustable. Figure 3 illustrates a cross-sectional view of an upright vacuum cleaner 1 of the type shown in Figure 2, in which the dust separator 10 is implemented according to an embodiment in the housing 2. The housing 2 comprises a motor fan 7 for generating an airflow and may further comprise one or more filters 8. Further, the dust separation chamber 11 of the dust separator 10 is arranged within the housing 2, and the air inlet 12 of the chamber 11 is in fluid communication with the interior of the profile 3. The motor fan 7 is capable of building up a negative pressure, thereby causing an airflow 21 to flow from an air inlet 22 at the nozzle 4 to the housing air outlet 13 via the housing air inlet 12 in an opening in the profile.

The shaft 14 and the plurality of disc members 15 of Figure 1 are not shown in Figure 3, but as is understood, a motor such as the motor of the fan 7 rotates the shaft and thus the disc members as has been described with reference to Figure 1 for separating debris and dust from the airflow 21 entering the air inlet 12, wherein the cleaned airflow enters the dust separation chamber 11 via the air outlet 13,

Figure 4a illustrates a cross-sectional view of the dust separator 10 according to another embodiment.

As illustrated in Figure 4a, in a section of the dust separation chamber 11 where the rotating disc members 15 faces the (static) air outlet 13 there will be a small gap and due to a pressure difference over the disc members in a radial direction, there will be a bypass path 16a, 16b where non-cleaned air will flow without contacting the disc members 15, and eventually reach the air outlet 13 where it will exit the chamber 11 without having been cleaned.

It should be noted that the amount of uncleaned air flowing via the bypass path 16a, 16b is small as compared to a total volume of air entering the air inlet 12. Nevertheless, the bypassing of uncleaned air is undesired.

Now, in prior art disc stack separators, this problem has been solved by sealing the gap in order to close the bypass path 16a, 16b, for instance with an annular flange (not shown) attached to an interior of the top section of the chamber 11, and extending towards - and contacting - an upper one of the disc members 15, thereby preventing uncleaned air to flow along the bypass path 16a, 16b and exit the chamber 11.

However, such an annular flange will cause friction to the upper one of the rotating disc members 15 which it contacts and will thus require increased energy consumption of a motor rotating the shaft 14. To the contrary, should such an annular flange be arranged such that it does not contact the upper one of the disc members 15, there will still be a small gap where dirty air will bypass the disc members 15.

In an embodiment, to solve this problem, the dust separation chamber 11 is arranged with one or more openings 17a, 17b in a top section of the chamber 11 where the disc members 15 faces the air outlet 13. It should be noted that the top section of the chamber 11, in which the openings 16a, 16b are arranged, is removably arranged to a main body of the chamber 11, as can be seen in Figure 4b where the top section is removed from the main body for emptying the dust separation chamber 11.

In a vacuum cleaner 1, the dust separator 10 is at negative pressure relative to the atmosphere, which negative pressure is created by the motor fan 7 illustrated in Figure 3. This has as an effect that air will flow through the openings 17a, 17b and thus advantageously counter any air flowing in the bypass path 16a, 16b. As a result, dust and debris entering the chamber 11 via the air inlet 11 will eventually contact the disc members 15 and be transported towards the inner wall of the chamber 11 by the centrifugal force caused by the rotating disc members 15. Advantageously, this will increase the particle- separation performance of the dust separator 10 while decreasing the energy required to rotate the shaft 14. The air can be supplied through the openings 17a, 17b from an outlet of the fan 7. It may be envisaged that the airflow applied to flow through the openings 17a, 17b may be controlled by a device such as valve (not shown).

Figure 5 illustrates a top view of the dust separator 10 of Figure 4 having a cylindrically-shaped dust separation chamber 11, where the shaft 14 extends longitudinally inside the air outlet 13. In this particular exemplifying embodiment, four openings 17a, 17b, 17c, I7d are annularly arranged in the section of the chamber 11 where the air outlet 13 is arranged. It should be noted that the dust separator may have a different structure than that shown in the Figures. For instance, the air outlet n could alternatively be arranged in a bottom section of the dust separation chamber n.

Figure 6 illustrates a cross-sectional view of the dust separator 10 according to a further embodiment, while Figure 7 illustrates a top view of the dust separator 10 of Figure 6.

In order to rotate the shaft 14 with smallest possible energy required by the motor rotating the shaft 14, at least one bearing 18 is arranged around the shaft 14, which bearing 18 is held in place by bearing brackets 19 attached to an inner wall of the air outlet 13.

Since the bearing 18 is operating in a dusty environment, particles will adhere to the bearing 18 and the ability of the bearing 18 to slide freely will be hampered by dirt.

To overcome this problem, the dust separator 10 will be configured to comprise a further air inlet 20 arranged along a periphery of the shaft 14 inside the air outlet 13 and ending at the bearing 18. A small amount of air will be entered into said further air inlet 20 for cleaning the bearing 18, i.e. for removing any dust and debris adhering to the bearing 18.

The further air inlet 20 arranged along the periphery of the shaft 14 inside the air outlet 13 is advantageous even though no bearing(s) would be used, for instance, air may be entered into further air inlet 20 in order to counter any particles exiting the dust separation chamber 11 via the outlet 14 (which could enter one or more motors located downstream of the chamber 11.

It should be noted that even though the openings I7a-i7d are shown in Figures 6 and 7, a dust separator 10 implementing the further air inlet 20 does not necessarily comprise the openings I7a-i7d.

The invention has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended patent claims.

Claims

1. An appliance (l) configured to clean an airflow comprising a dust separator (10), which dust separator (10) comprises:

a dust separation chamber (n) comprising:

an air inlet (12) where an airflow to be cleaned enters the dust separation chamber (11);

an air outlet (13) where the cleaned airflow exits the dust separation chamber (11);

a shaft (14) arranged along a longitudinal axis of the dust separation chamber (11); and

a plurality of spaced apart disc members (15) arranged along the shaft (14), the shaft (14) being arranged to rotate the disc members (15) in order to cause a centrifugal force which transports particles contained in the airflow entering the air inlet (12) towards an inner wall of the dust separation chamber (11), while causing the airflow to move towards a centre of the spaced apart disc members (15) for travelling towards the air outlet (13) and exit the dust separation chamber (11).

2. The appliance (1) of claim 1, the dust separation chamber (11) being arranged with at least one opening (i7a-i7d) in a section of the chamber (11) where one of the disc members (15) faces the air outlet (13), wherein air is entered into the dust separation chamber (11) via the at least one opening (i7a-i7d) in order to counter an airflow flowing from the air inlet (12), via a bypass path (16a, 16b) created between said one of the disc members (15) and said section, to the air outlet (13).

3. The appliance (1) of claim 2, wherein the air is entered into the dust separation chamber (11) via the openings (i7a-i7d) by causing the dust separator (10) to be at negative pressure relative to the atmosphere.

4. The appliance (1) of claim 3, further comprising:

a motor fan (7) causing the negative pressure.

5. The appliance (1) of any one of claims 2-4, the at least one opening (17a- 17c!) being arranged in a top section of the dust separation chamber (11).

6. The appliance (1) of claim 5, the top section of the dust separation chamber (11) being removably attached to a main body of the chamber (11).

7. The appliance of any one of the preceding claims, the air inlet (12) and the air outlet (13) being arranged such that the airflow entering the air inlet (12) is substantially perpendicular to the airflow exiting the dust separation chamber (11) via the air outlet (13).

8. The appliance (1) of any one of the preceding claims, the air outlet (13) being aligned with a longitudinal axis of the dust separation chamber (11) extending at the centre of the plurality of disc members (15).

9. The appliance (1) of any one of the preceding claims, the dust separator (10) further comprising:

a motor arranged to be in connection with the shaft (14) for rotating the shaft (14) and the disc members (15).

10. The appliance (1) of any one of the preceding claims, the shaft (14) being arranged to extend longitudinally inside the air outlet (13).

11. The appliance (1) of any one of the preceding claims, the dust separator (10) further comprising:

at least one bearing (18) arranged around the shaft (14) and further being arranged to be held in place by bearing brackets (19) attached to an inner wall of the air outlet (13).

12. The appliance (1) of claim 11, the dust separator (10) further

comprising:

a further air inlet (20) arranged along a periphery of the shaft (14) inside the air outlet (13) and ending at the bearing (18), via which air is entered in order to clean the bearing (18).

13. The appliance (1) of any one of claims 1-10, the dust separator (10) further comprising:

a further air inlet (20) arranged along a periphery of the shaft (14) inside the air outlet (13, via which air is entered in order to counter any particles exiting the dust separation chamber (11).

14. The appliance (1) of any one of the preceding claims, the appliance being a vacuum cleaner or an air-cleaner.