NZ615493A - Vacuuming device comprising a vacuum cleaner and a bag filter - Google Patents

Abstract

Disclosed is a vacuuming bag that folds to form a 3D shape that is easier to manufacture and more completely fills the cavity that it is in. The device comprises a vacuum cleaner and a bag filter and in which the bag filter is designed as a non-woven bag filter, as a disposable bag filter, and as a flat bag having a first bag filter wall and a second bag filter wall. The bag filter has at least one superficial fold, each of which has regions lying within the area of the bag filter wall and regions that project from the area of the bag filter wall and can unfold during a vacuuming operation. The vacuum cleaner has a bag filter-holding compartment with rigid walls, on which at least one first spacer is provided in such a way as to keep the regions of at least one superficial fold that lie within the area of the bag filter wall at a distance from the wall of the bag filter-holding compartment, and a second spacer is provided in such a way as to keep the unfolded regions of the at least one superficial fold at a distance from the wall of the bag filter-holding compartment.

Description

Vacuuming Device Comprising a Vacuum Cleaner and a Bag Filter FIELD OF THE INVENTION The invention relates to vacuum cleaning apparatus comprising a vacuum cleaner and a filter bag which is formed as a non-woven fabric filter bag, as a disposable filter bag and as a flat bag with surface folds.

PRIOR ART Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.

Filter bags in the form of disposable flat bags and made of a non-woven fabric are those filter bags that are nowadays most commonly used. The advantage of non-woven fabric bags (as opposed to filter bags made of paper) is the substantially higher dust absorption capacity of the filter bag, along with a high collection efficiency and longer service life. The flat bag shape is the most widely spread shape for non-woven fabric bags as bags having this shape are very easy to manufacture. As opposed to the paper filter material used for paper filter bags the non-woven fabric material is very hard to fold permanently owing to the great resilience, so that the manufacture of more complex bag shapes, such as block bottom bags or other bag shapes having a bottom, is very complicated and expensive.

Flat bags as used in the present invention are filter bags whose filter bag wall comprised of two individual layers of a filter material with identical surface areas is formed such that the two individual layers are connected to each other only at their circumferential edges (the term identical surface area does not preclude, of course, that the two individual layers differ from each other by the fact that one of the layers includes an inlet opening).

The connection of the individual layers may be realized by a welding seam or adhesive seam along the total circumference of the two individual layers. However, it may also be realized such that one individual layer made of a filter material is folded about one of its axes of symmetry while the other, open circumferential edges of the so created two sub- layers are welded or bonded to each other (so-called tubular bag). Thus, this type of manufacture requires three welding or bonding seams. Two of those seams then form the filter bag edge. The third seam may equally form a filter bag edge or lie in one of the filter bag walls.

An individual filter material layer taken by itself may, in this design, consist of one or more layers which can be laminated, for instance.

Flat bags as used in the present invention may also comprise so-called gussets.

These gussets may be fully unfoldable. A flat bag having such gussets is shown, for instance, in DE 20 2005 000 917 U1 (see Fig. 1 with folded gussets, and Fig. 3 with unfolded gussets). Alternatively, the gussets may be welded to sections of the circumferential edge.

Such a flat bag is shown in DE 10 2008 006 769 A1 (see Fig. 1 thereof).

It necessarily follows from the above definition of the term flat bag that flat bags are two-dimensional structures immediately after the manufacture thereof, i.e. they have an internal volume prior to their use that is substantially equal to zero.

However, a filter bag with an internal volume that is substantially equal to zero (prior to its use) is not necessarily a flat bag within the meaning of the present invention, as bag shapes having a bottom, as described for instance in DE 20 2005 016 309 U1 or DE 20 2009 004 433 U1, are not flat bags because they are not formed of two individual layers having identical surface areas that are connected to each other only at their circumferential edges.

In the light of the above definitions it is a matter of course that bag shapes that are already three-dimensional structures after their manufacture and, thus, have an internal volume different from zero, as are described for instance in WO 00/00269 (see Figs. 27 and 28 thereof) and DE 10 2007 060 748 (see in particular Fig. 9 thereof), are not flat bags in accordance with the present invention.

A non-woven fabric bag in accordance with the present invention comprises a filter material of a non-woven fabric. A dry-laid or wet-laid non-woven fabric, or an extruded non- woven fabric, in particular a melt-spun micro-fiber spunbonded non-woven fabric (melt-blown non-woven fabric) or filament spunbonded non-woven fabric (spunbond) may be used as non-woven fabric material. In addition nanofiber layers may be provided. The differentiation between wet-laid non-woven fabrics, respectively nonwovens, and conventional wet-laid paper is made in accordance with the definition provided below, which is also used by EDANA (International Association Serving the Nonwovens and Related Industries).

Therefore, a conventional (filter) paper is not a non-woven fabric.

The non-woven fabric may include staple fibers or endless fibers. With regard to the manufacturing is is also possible to provide several layers of staple fibers and endless fibers which are bonded to exactly one layer of non-woven fabric.

The filter material may also be a laminate made of several non-woven fabric layers, e.g. filament spunbonded non-woven fabric and melt-blown non-woven fabric (SMS, SMMS or Sn MS). Such a laminate may be laminated or also calendered by means of a hot adhesive. The layer of melt-blown non-woven fabric may be creped.

The term non-woven fabric (nonwoven) is used according to the definition in the ISO standard ISO 9092:1988, respectively standard EN 29092. In particular, in the field of the non-woven fabric manufacture the terms fibrous web or nonwoven and non-woven fabric are differentiated as defined below, and should be understood in accordance with this definition also within the limits of the present invention. To produce a non-woven fabric, fibers and/or filaments are used. The loose and still non-connected fibers and/or filaments are called nonwoven or fibrous web (web). In a so-called nonwoven bonding step a non-woven fabric is finally created from such a fibrous web, the tenacity of which is sufficient, for instance, to be wound to rollers. In other words, a non-woven fabric becomes self-supporting by the bonding. (Details about the use of the definitions described herein and/or methods may be also learned from the standard work “Vliesstoffe”, W. Albrecht, H. Fuchs, W.

Kittelmann, Wiley-VCH, 2000).

The filter bag wall comprises at least one surface fold. The design of such surface folds is shown, for instance, in the European patent application 10163463.2 (see in particular Fig. 10a and Fig. 10b, respectively Fig. 11a and Fig. 11b thereof). If the filter bag wall comprises a plurality of surface folds this material is also called a pleated filter material. Such pleated filter bag walls are shown in the European patent application 10002964.4.

Fig. 1 and Fig. 2 show a cross-section of a filter bag comprising a wall with two surface folds. Such surface folds enlarge the filter surface of the filter bag so that a higher dust absorption capacity of the filter bag, along with a high collection efficiency and longer service life is obtained (as compared with a filter bag having same outer dimensions and without surface folds).

Fig. 1 shows a filter bag 1 comprising a filter bag wall 10 with two surface folds 11 in the form of so-called dovetail folds. The figure shows a cross-section of the filter bag through the filter bag center. The longitudinal axes of the surface folds accordingly extend in one plane which, again, extends perpendicular to the plane of projection, and the surface folds extend at their longitudinal ends into the welding seams of the filter bag which extend in parallel to the plane of projection and are positioned in front of and behind the plane of projection. Thus, the strongest unfolding of the surface folds is in the middle thereof. The filter bag is here shown in a state in which the surface folds are already unfolded to some extent. Each dovetail fold 11 includes areas 11a positioned within the surface area of the filter bag wall 12, and areas 11b projecting over the surface area of the filter bag wall 12.

These areas 11b are not yet unfolded when inserting the filter bag into the vacuum cleaner for the first time.

Fig. 2 shows a filter bag 2 comprising a filter bag wall 20 with two surface folds 21 in the form of so-called triangular folds. The figure equally shows a cross-section of the filter bag through the filter bag center. The longitudinal axes of the surface folds accordingly extend in one plane which, again, extends perpendicular to the plane of projection, and the surface folds extend at their longitudinal ends into the welding seams of the filter bag which extend in parallel to the plane of projection and are positioned in front of and behind the plane of projection. Thus, the strongest unfolding of the surface folds is in the middle thereof.

In this case, too, the filter bag is shown in a state in which the surface folds are already unfolded to some extent. Each triangular fold 21 includes areas 21a positioned within the surface area of the filter bag wall 22, and areas 21b projecting over the surface area of the filter bag wall 22. These areas 21b are not yet unfolded when inserting the filter bag into the vacuum cleaner for the first time.

The second filter bag wall of the filter bag illustrated in Fig. 1 and Fig. 2 does not have surface folds. Of course, this second filter bag wall, too, may comprise one or more surface folds.

Apart from the surface folds illustrated in Fig. 1 and Fig. 2 surface folds having different shapes are feasible, too. It should not be regarded as a limitation that the surface folds in the embodiments of Fig. 1 and Fig. 2 extend perpendicular to a bag edge. Of course, the surface folds may also extend at an angle to the bag edges.

Vacuum cleaners according to the prior art have filter bag receiving spaces with rigid walls. For a filter bag to develop its filter effect these walls comprise spacer devices in the form of ribs, respectively rib-shaped sections to prevent the filter bag from bearing with its filter surface against the wall of the filter bag receiving space, thus reducing the effective filter effect.

DESCRIPTION OF THE INVENTION It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

An object of the invention in at least one preferred form is to improve the vacuum cleaning apparatus comprising a vacuum cleaner and a filter bag as known from the prior art in such a way that the dust absorption capacity of the filter bag is further increased, along with a higher collection efficiency and longer service life.

In one aspect, the present invention provides a vacuum-cleaning apparatus comprising a vacuum cleaner and a filter bag in which the filter bag is formed as a non-woven fabric filter bag, as a disposable filter bag and as a flat bag having a first filter bag wall and a second filter bag wall, the filter bag has at least one surface fold, wherein each surface fold comprises areas that are positioned within the surface area of the filter bag wall, and areas that project over the surface area of the filter bag wall and are capable of being unfolded during the vacuum-cleaning, the vacuum cleaner comprises a filter bag receiving space with rigid walls, wherein on the walls of the filter bag receiving space at least a first spacer device is provided to space the areas of at least one surface fold positioned within the surface area of the filter bag wall away from the wall of the filter bag receiving space, and at least a second spacer device is provided to space the unfolded areas of the at least one surface fold away from the wall of the filter bag receiving space.

Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”.

By providing this (these) special spacer device(s) for the areas of the surface fold(s) positioned within the surface area of the filter bag wall and the special spacer devices for the areas of the surface fold projecting over this surface area the surface fold can unfold in such a way that the major part of the surface area of the filter material forming the surface fold becomes exposed to a flow. Thus, the effective filter surface of the filter bag is enlarged (as opposed to the use in a conventional vacuum cleaner) so that the dust absorption capacity of the filter bag, along with a higher collection efficiency and higher service life, can be further increased as compared to this conventional apparatus.

According to a preferred further development of the invention the height of the first and/or the second spacer devices with respect to the wall of the filter bag receiving space may be in a range of 5 mm to 60 mm, preferably of 10 mm to 30 mm. These dimensions allow an optimal adaptation of the filter bag receiving space to filter bags with surface folds.

Corresponding to another further development of the above-described inventions each first and each second spacer device may be formed as a web, a web-shaped section, a bow, a bow-shaped section, a rib, a rib-shaped section and/or a lug. This further development allows a comparatively uniform, optimal flow exposure of the filter surface of the total filter bag inside the filter bag receiving space of the vacuum cleaner.

According to another further development of the above described invention each first and each second spacer device may be formed integrally with the wall of the filter bag receiving space. Thus, the filter bag receiving space of the vacuum cleaner may be manufactured by an injection molding process. This ensures a simple and inexpensive manufacture of the filter bag receiving space.

Alternatively, all first and all second spacer devices may also be formed as a cage- shaped insert which is provided in the filter bag receiving space. By this further development it is possible to retrofit already existing vacuum cleaners. In this design, the cage-shaped insert may be formed to be removable from the filter bag receiving space and insertable into the filter bag receiving space.

According to a further development of all above-described inventions the filter bag may comprise several, preferably three to seven surface folds in the first layer of the filter bag wall and/or several, preferably three to seven surface folds in the second layer of the filter bag wall. Surprisingly, it has shown that this configuration allows the optimum ratio between the dust absorption capacity of the filter bag, along with a high collection efficiency and long service life, and a cost-efficient production of the filter bags.

BRIEF DESCRIPTION OF THE DRAWING The attached drawing serves to explain the prior art and the invention, in which Fig. 1 shows a filter bag according to the prior art with two surface folds in the form of dovetail folds; Fig. 2 shows a filter bag according to the prior art with two surface folds in the form of triangular folds; Fig. 3 a first embodiment of the present invention; and Fig. 4 a first embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Fig. 3 shows a first embodiment of the present invention. This embodiment is particularly suited for a filter bag with dovetail folds as illustrated in Fig. 1.

Fig. 3 shows the filter bag with fully unfolded surface folds 31. The areas 31a, which are positioned within the surface area of the filter bag wall 32, are spaced away by a first spacer device 35 from the wall of the filter bag receiving space 33. The areas 31b, which project over the surface area of the filter bag wall 32, are spaced away by a second spacer device 36 from the wall of the filter bag receiving space 33.

As is recognizable in Fig. 3, the height of the first and second spacer devices depends on both the size of the surface fold and the shape of the filter bag receiving space.

If the filter bag receiving space has, in accordance with the embodiment of Fig. 3, a shape that is similar to the shape of the filter bag in operation the spacer devices may be formed smaller than in a case where the filter bag space is substantially cuboid-shaped, as is common in the prior art. In the latter case, in particular if the filter bag comprises several surface folds, the first spacer devices for the various surface folds will also have a different size. The same applies to the second spacer devices (see in this respect the embodiment discussed in connection with Fig. 4).

In the present case, the first and second spacer devices are formed as web- shaped sections which extend section-wise along the surface fold.

According to this embodiment the first and the second spacer devices are formed integrally with the wall of the filter bag receiving space 33. This allows a simple production of the filter bag receiving space, for instance by an injection molding process.

Alternatively, the first and second spacer devices may also be formed as ribs, a rib- shaped section and/or a lug.

Fig. 4 shows a second embodiment of the present invention. This embodiment is particularly suited for a filter bag with triangular folds as illustrated in Fig. 2.

Fig. 4 shows the filter bag with fully unfolded surface folds 41. The areas 41a, which are positioned within the surface area of the filter bag wall 42, are spaced away by a first spacer device 45 from the wall of the filter bag receiving space. The areas 41b, which project over the surface area of the filter bag wall 42, are spaced away by a second spacer device 46 from the wall of the filter bag receiving space.

Regarding shape and size of the first and second spacer devices the statements made in connection with the first embodiment apply analogously.

According to a third, non-illustrated embodiment of the invention the first and second spacer devices are provided in the form of a cage. The outer shape of this cage is predefined by the second spacer devices spacing away the areas of the surface folds that extend beyond the surface area of the filter bag wall. Usefully, all bars forming the second spacer devices run substantially parallel to each other and substantially parallel to the surface folds of the filter bags if these are inserted into the cage as intended. Equally substantially parallel to these bars run the bars that form the first spacer devices. These bars reproduce the shape of the surface areas of the filter bag and, accordingly, extend into the interior of the cage formed by the second spacer devices.

If necessary, it is also possible to provide cage bars which run at an angle, in particular perpendicular to the bars forming the first and second spacer devices. Such bars running at an angle serve to stabilize specific areas of the filter bag, e.g. the area of the inlet opening.

Claims (8)

1. Vacuum-cleaning apparatus comprising a vacuum cleaner and a filter bag in which the filter bag is formed as a non-woven fabric filter bag, as a disposable filter bag and as a flat bag having a first filter bag wall and a second filter bag wall, the filter bag has at least one surface fold, wherein each surface fold comprises areas that are positioned within the surface area of the filter bag wall, and areas that project over the surface area of the filter bag wall and are capable of being unfolded during the vacuum-cleaning, the vacuum cleaner comprises a filter bag receiving space with rigid walls, wherein on the walls of the filter bag receiving space at least a first spacer device is provided to space the areas of at least one surface fold positioned within the surface area of the filter bag wall away from the wall of the filter bag receiving space, and at least a second spacer device is provided to space the unfolded areas of the at least one surface fold away from the wall of the filter bag receiving space.

2. Apparatus according to patent claim 1, in which the height of the first and/or the second spacer devices with respect to the wall of the filter bag receiving space is in a range of 5 mm to 60 mm.

3. Apparatus according to any one of the preceding patent claims, in which each first and each second spacer device is formed as a web, a web-shaped section, a bow, a bow- shaped section, a rib, a rib-shaped section and/or a lug.

4. Apparatus according to any one of the preceding patent claims, in which each first and each second spacer device is formed integrally with the wall of the filter bag receiving space.

5. Apparatus according to any one of the patent claims 1 to 4, in which all first and all second spacer devices are formed as a cage-shaped insert which is provided in the filter bag receiving space.

6. Apparatus according to patent claim 5, in which the cage-shaped insert is removable from the filter bag receiving space and reinsertable into the filter bag receiving space.

7. Apparatus according to any one of the preceding patent claims, in which the filter bag comprises three to seven surface folds in the first layer of the filter bag wall and/or three to seven surface folds in the second layer of the filter bag wall.

8. Apparatus according to claim 2, in which the height of the first and/or the second spacer devices with respect to the wall of the filter bag receiving space is in a range of 10 mm to 30 mm.