WO2004100749A1

WO2004100749A1 - Ceramic filter and cleaning appliance, in particular vacuum cleaner

Info

Publication number: WO2004100749A1
Application number: PCT/EP2004/005303
Authority: WO
Inventors: Wolfgang Kemmerzell; Albert Kleinhenz; Michael Krammer; Georg Schwalme; Thomas Strehler
Original assignee: BSH Bosch und Siemens Hausgeräte GmbH
Priority date: 2003-05-15
Filing date: 2004-05-17
Publication date: 2004-11-25
Also published as: DE10321955A1; CN1791349A; EP1624782A1

Abstract

The invention relates to a ceramic filter (10), in particular for use in a vacuum cleaner (12). Said filter (10) surrounds a chamber (14) equipped with an inlet for air laden with foreign particles, the air exiting the chamber in a purified form at least partially via pores of the ceramic material (16). To increase the active surface of the ceramic filter (10), at least some sections of the delimiting walls (18, 20; 18', 20'; 18'', 20'') of the chamber that consist of ceramic material are configured with a corrugated form, for example undulating or rake-shaped, in order to enlarge the surface area of said walls. Comparable advantages can be achieved with a surface filter if said surface has a corrugated form. The inventive configuration enables the efficiency of the filter action to be increased for a given installation area.

Description

Ceramic filter and cleaning device, in particular vacuum cleaner

The invention relates to ceramic filters, in particular for use in a vacuum cleaner, according to the preambles of claims 1 and 7.

The invention further relates to a cleaning device, in particular a vacuum cleaner.

Conventional vacuum cleaners work on the principle that air laden with foreign particles is sucked in, filtered in the vacuum cleaner and blown out of the vacuum cleaner in a cleaned form. Since a wide variety of foreign particles or foreign bodies can be contained in the sucked-in air, special requirements must be placed on the filter devices within the vacuum cleaner. For this reason, it is customary to arrange different filter devices one behind the other in relation to the main flow direction of the air laden with foreign particles, these filter devices performing different tasks. For example, it is known to collect coarser foreign particles in a filter bag and then to guide the air flowing out of the filter bag through a fine-pored filter fleece, so that remaining fine foreign particles can also be filtered out before the air is blown out into the atmosphere. For such a function assignment to the individual filter devices, it is necessary to select the pore size in the filter devices accordingly.

In order to filter out very fine foreign particles from the air, so-called HEPA filters (High Efficiency Particulate Air) are often used in vacuum cleaners. These usually consist of a glass fiber composite, which is arranged in a carrier material, for example paper. With these HEPA filters it is possible to remove very small, harmful particles, in particular allergy-causing substances, from the air to be blown out. These substances include, for example, pollen, fungi and mites or their metabolites or components.

Even if good results are achieved with such HEPA filters, it is nevertheless a disadvantage that the filters are of complex construction and have to be replaced after a certain period of operation due to their contamination. It is also. known to use filters made of ceramic material. An example of a vacuum cleaner with a ceramic filter device is disclosed in WO 01/41619 A1.

In connection with ceramic filter devices, it has already been proposed in an unpublished patent application to use one which can be cleaned pyrolytically, that is to say by heating to, for example, 500 ° C. Ceramic foams made of aluminum dioxide are suitable for this. Because of their regenerability, ceramic filters are therefore advantageous compared to numerous other filter devices.

A known ceramic filter, which also serves as a dust filter, is designed as a rectangular ceramic box with an inlet opening. Air loaded with foreign particles is supplied through the inlet opening, which then exits through the porous ceramic in a cleaned form. The coarser dirt collects in the box; fine dust remains in the ceramic pores.

The invention has for its object to further develop generic ceramic filters and thus the cleaning devices for which they are intended so that the filter effect is improved.

This object is achieved with the features of the independent claims.

Advantageous embodiments of the invention are specified in the dependent claims.

The invention is based on the generic ceramic filter according to claim 1 in that the boundary walls of the room, which are made of ceramic material, are at least partially wave-shaped to increase their surface area. The wave-like shape of the surface increases it compared to a flat surface. This increases the active surface of the ceramic filter and thus the filter effect. In particular, the ceramic filter can be used over a longer, uninterrupted period without being cleaned. A large surface of the ceramic filter further reduces the internal frictional resistance, which increases the suction power of the vacuum cleaner for a given electrical power. The invention is further developed in a particularly advantageous manner in that cross-sectional boundary walls are at least partially shaped in a meandering manner so that the boundary walls have peaks and valleys. Such a meandering design can be easily implemented with ceramics, and it creates a considerable increase in the active surface.

For comparable reasons, it can make sense that opposite boundary walls are at least partially shaped like a rake in cross section, so that the boundary walls have peaks and valleys.

The ceramic filter according to the invention can be developed in a useful manner in that the mountains of opposite boundary walls are at least partially opposite one another and that the valleys of opposite boundary walls are at least partially opposite one another. In this way, only a very small installation space is required despite the curved surface, since the curved surfaces interlock.

However, it can also make sense for mountains and valleys to lie at least partially opposite boundary walls. In this way, an enlarged space between the boundary walls is made available, so that the dust holding capacity is increased.

This is particularly useful in a further development of the invention, in which it is provided that the space is a hollow chamber which is closed except for the inlet opening, so that air can only escape through the pores of the ceramic. In this way, the blown-out air is thoroughly cleaned, the volume of dust being absorbed being limited by the volume of the hollow chamber.

In a further embodiment, the invention builds on the generic ceramic filter according to claim 7 in that the surface for enlarging its surface is at least partially wave-shaped. With a surface filter, too, it makes sense to increase the surface area to increase the active filter area in order to increase the period of use between the cleaning cycles and the air capacity that can be conveyed. In the case of a surface filter, a preferred embodiment also provides that the surface is at least partially shaped like a meander in cross section.

It can also make sense that the surface is at least partially shaped like a rake in cross section.

In particularly preferred embodiments of the present invention, it is provided that the ceramic filter can be thermally regenerated. Due to the thermal regenerability, the ceramic filter can be cleaned in a simple and thorough manner, so that the filter effect can be made available again without the need to be exchanged for another filter.

In this context, it is particularly useful that a heating device is provided on the ceramic filter. The cleaning can therefore take place in the device while the device is in operation. Due to the curved shape of the surfaces of the ceramic filter, the

Heating device be inserted deep into the ceramic filter. As a result, the filter can be regenerated in a shorter time with less energy consumption. For the purpose of

The ceramic filter device, which is electrically insulating in itself, can be heated with

Silicon are treated, which is embedded in the pores. It is then only necessary to apply an electrical voltage to the ceramic filter via graphite electrodes in order to bring about heating.

The invention further relates to a cleaning device, in particular a vacuum cleaner, with a ceramic filter according to the invention. In this way, the advantages and special features of the ceramic filter according to the invention are realized when used in a cleaning device.

In this context, it can be useful for the ceramic filter to be arranged downstream of at least one other filter device of the cleaning device with respect to a main direction of flow of the air. The ceramic filter device thus serves for fine filtering, in particular allergy-producing substances are to be removed from the air. In this context, ceramics with a pore size of 10 μm or smaller are preferred. However, it is also conceivable to use the ceramic filter device as the primary filter device. direction, for example as a ceramic dust collector, to be provided in the cleaning device, in particular since ceramics with different pore sizes are available.

It can also be useful for the ceramic filter to have at least one further filter device downstream of the main flow direction of the air. Since ceramic filter devices with different pore sizes can be used, a downstream filter device for fine filtering can be useful when using comparatively large pores. This can also be realized by a ceramic filter device, but with a smaller pore size.

In this context, it is useful that the at least one further filter device comprises a HEPA filter. This combines the advantages of the pyrolytically cleanable ceramic filter with the reliability of proven HEPA filters. Due to the filtering of the air by the ceramic filter and the associated removal of fine particles from the air, the HEPA filter has a considerably longer service life due to this combination.

It is usefully provided that the ceramic filter can be removed from the cleaning device for cleaning purposes without the use of tools. As a result, the ceramic filter can be freed of the dust accumulated in the chamber in a simple manner, for example when it is designed with a hollow chamber, and can optionally be thermally regenerated in an oven.

The invention is based on the finding that the filter effect is improved by the wave-like shaping of the surface. In particular, the time between cleaning cycles increases and the suction power of the vacuum cleaner can be improved for a given electrical power. In addition to the application of the invention to a vacuum cleaner, numerous other applications can be considered, for example in air conditioning systems or air washing systems.

The invention will now be explained by way of example with reference to the accompanying drawings using preferred embodiments. It shows:

Figure 1 is a schematic sectional view of part of an inventive

Cleaning equipment;

Figure 2 is a sectional view of a first embodiment of a ceramic filter according to the invention;

Figure 3 is a sectional view of a second embodiment of a ceramic filter according to the invention;

Figure 4 is a sectional view of a third embodiment of a ceramic filter according to the invention; and

FIG. 5 shows a sectional view of a fourth embodiment of a ceramic filter according to the invention.

Figure 1 shows a schematic sectional view of part of a cleaning device according to the invention. The representation is highly schematic. In particular, the relative dimensions of the components shown are chosen in part arbitrarily. A plurality of filter devices are provided in a housing 30 of a vacuum cleaner 12. The air symbolized by an arrow initially flows into a filter device 26, which can be a conventional filter bag, for example. The air flowing out of the filter bag 26 then reaches a ceramic filter 10 according to the invention, so that fine particles remaining in the air are filtered out of the vacuum cleaner 12 before the air is blown out. The ceramic filter 10, which consists of a ceramic foam that includes, for example, aluminum oxide, has a pore size on the order of 10 μm or less, so that the finest particles can be filtered out. Nevertheless, it can make sense to arrange a further filter 28 in the flow direction of the air behind the ceramic filter 10 in order to carry out a fine filtering again. This filter 28 can be a HEPA filter known in the prior art, which has proven itself above all to filter out allergy-causing substances. In particular, when using a downstream HEPA filter 28, the pore size of the ceramic filter 10 can also be selected to be larger thus assigning the ceramic filter 10 the task of first filtering out coarser particles from the air stream. The mode of action can thus be determined via the pore size 10 of the ceramic filter. This can go so far that the ceramic filter 10 can be used in a vacuum cleaner 12 without an upstream filter device 26, that is to say can form the primary filter device. The ceramic filter 10 can be provided with a heating device (not shown) which enables the ceramic filter 10 to be thermally regenerated during operation. It can also be provided that the ceramic filter 10 can be removed from the cleaning device 12 for cleaning purposes without the use of tools.

Figure 2 shows a sectional view of a first embodiment of a ceramic filter according to the invention. A space 14 enclosed by a ceramic 16 formed as a thin layer can be seen, which is preferably designed as a hollow chamber. Furthermore, an inlet opening (not shown) is provided for the entry of air loaded with foreign particles into the space 14. The inlet opening is preferably circular with a diameter in the range from 20 to 40 mm. The ceramic filter 10 comprises two opposing boundary walls 18, 20, which are meandered in cross section. The "mountains" resulting from the meandering formation lie opposite one another, as well as the resulting "valleys".

Air to be cleaned enters the space 14 in the ceramic filter 10 through the inlet opening (not shown) and flows out through the ceramic 16. In order to influence the suction power of the vacuum cleaner as little as possible due to the passage of air through the ceramic 16, the ceramic 16 is preferably made as thin as possible; for example, its thickness is a few millimeters. This also applies to the embodiments of ceramic filters according to the invention described below.

FIG. 3 shows a sectional view of a second embodiment of a ceramic filter according to the invention. In contrast to Figure 2, the boundary walls 18 ', 20' are shaped like a rake. These boundary walls 18 ', 20' interlock so that the mountains of the boundary walls 18 ', 20' are opposite each other; the valleys of the boundary walls 18 ', 20' are also opposite one another. With regard to the inlet opening and the other features of the second embodiment of the invention Ceramic filter according to FIG. 3 is referred to the explanations for the first embodiment according to FIG. 2.

FIG. 4 shows a sectional view of a third embodiment of a ceramic filter according to the invention. The properties with regard to the inlet opening and the ceramic are also similar again, as explained in connection with FIG. 2 and FIG. 3. The boundary walls 18 ', 20' again have a meandering shape in cross section. In contrast to FIG. 2, however, the valleys of the boundary wall 18 "lie opposite the mountains of the boundary wall 20". Conversely, the mountains of the boundary wall 18 "face the valleys of the boundary wall 20". A larger amount of dust can thus accumulate in the space 14 which is enclosed by the ceramic 16, so that the ceramic filter 10 has to be emptied less frequently. In order to achieve this advantage, one may accept the disadvantage compared to FIG. 2, namely that the ceramic filter 10 according to FIG. 4 has a much larger construction than the ceramic filter 10 according to FIG. 2.

FIG. 5 shows a sectional view of a fourth embodiment of a ceramic filter according to the invention. The ceramic filter 10 shown here is designed as a surface filter, the surface 22 in turn being shaped like a meander. Other curvatures of the surface are also conceivable, such as a rake-like shape. An air stream 24 to be cleaned flows through the ceramic filter 10, the dirt particles remaining on the surface. The ceramic filter 10 can be arranged as a flat component in the air flow. It is also conceivable that it forms a boundary wall of a dust container into which air to be cleaned enters and exits through the ceramic filter 10 in a cleaned form.

The different embodiments of ceramic filters according to FIGS. 2 to 5 can be manufactured in different ways. It is possible to use sand casting, centrifugal casting, a divisible casting mold or a lost wax process.

The features of the invention disclosed in the above description, in the drawings and in the claims can be essential both individually and in any combination for realizing the invention. LIST OF REFERENCE NUMBERS

10 ceramic filters

12 vacuum cleaner / cleaning device

14 room

16 ceramics

18, 18 ', 18 "boundary walls

20, 20 ', 20 "boundary walls

22 area

24 airflow

26 filter device

28 filters

30 housing

Claims

claims

1. Ceramic filter (10), in particular for use in a vacuum cleaner (12), the ceramic filter (10) surrounding a space (14) with an inlet opening for air loaded with foreign particles, which is at least partially cleaned by pores of the ceramic (16) - Niger form emerges from the room (14), characterized in that the boundary walls (18, 20; 18 ', 20'; 18 ", 20") made of ceramic material of the room are at least partially wave-shaped to increase their surface area.

2. Ceramic filter (10) according to claim 1, characterized in that opposite boundary walls (18, 20; 18 ", 20") are at least partially shaped in a meandering manner in cross section, so that the boundary walls have mountains and valleys.

3. Ceramic filter (10) according to claim 1 or 2, characterized in that opposite boundary walls (18 ', 20') are at least partially shaped like a computing cross-section, so that the boundary walls have peaks and valleys.

4. Ceramic filter (10) according to claim 2 or 3, characterized in

that the mountains of opposing boundary walls (18, 20; 18 ', 20') are at least partially opposite each other and

that the valleys of opposite boundary walls (18, 20; 18 ', 20') are at least partially opposite.

5. Ceramic filter (10) according to one of claims 2 to 4, characterized in that mountains and valleys of opposite boundary walls (18 ", 20") are at least partially opposite.

6. Ceramic filter (10) according to one of the preceding claims, characterized in that the space (14) is a closed hollow chamber except for the inlet opening, so that the escape of air is only possible through the pores of the ceramic.

7. Ceramic filter (10), in particular for use in a vacuum cleaner, wherein the ceramic filter (10) has a flat shape so that air passes through the surface (22) of the ceramic filter (10) and in a cleaned form from the ceramic filter (10) can emerge, characterized in that the surface (22) is at least partially wave-shaped to enlarge its surface.

8. Ceramic filter (10) according to claim 7, characterized in that the surface (22) is at least partially shaped like a meander in cross section.

9. Ceramic filter (10) according to claim 7 or 8, characterized in that the surface is at least partially shaped like a rake in cross section.

10. Ceramic filter (10) according to one of the preceding claims, characterized in that the ceramic filter (10) is thermally regenerable.

11. Ceramic filter (10) according to claim 10, characterized in that a heating device is provided on the ceramic filter (10).

12. Cleaning device (12), in particular vacuum cleaner, with a ceramic filter (10) according to one of the preceding claims.

13. Cleaning device (12) according to claim 11, characterized in that the ceramic filter (10) is arranged at least one other filter device (26) of the cleaning device (12) with respect to a main flow direction of the air.

14. Cleaning device (12) according to claim 12 or 13, characterized in that the ceramic filter (10) is followed by at least one further filter device (28) with respect to a main flow direction of the air. ,

15. Cleaning device (12) according to claim 14, characterized in that the at least one further filter device (28) comprises a HEPA filter.

16. Cleaning device (12) according to one of claims 12 to 15, characterized in that the ceramic filter (10) for cleaning purposes, the cleaning device (12) can be removed without the use of tools.