DK2502538T3

DK2502538T3 - Vacuum cleaner filter bag with filterposevægforbindelsesindretning

Info

Publication number: DK2502538T3
Application number: DK11002353.8T
Authority: DK
Inventors: Ralf Sauer; Jan Schultink
Original assignee: Eurofilters Holding Nv
Priority date: 2011-03-22
Filing date: 2011-03-22
Publication date: 2015-12-07
Also published as: PL2502538T3; EP2502538B1; EP2502538A1; ES2549493T3

Description

FIELD OF THE INVENTION

The invention relates to vacuum cleaner filter bags, also referred to in the following in short as filter bags, which are configured as nonwoven filter bags, as disposable filter bags and as flat bags having surface folds.

PRIOR ART

Filter bags in the form of disposable flat bags consisting of nonwoven fabric are at present the most commonly used filter bags. The advantage of nonwoven fabric bags (compared to paper filter bags) is the substantially higher dust absorption capacity of the filter bag with a higher separation efficiency and a longer service life. The flat bag form is the most widely used form of nonwoven bags since it is very easy to produce this form of bag. Unlike the paper filter material used for paper filter bags, nonwoven filter material cannot be easily folded in a permanent manner due to the high resilience thereof, and so the production of more complex bag forms, such as block bottom bags or other bag forms with a base is very complex and expensive.

Flat bags within the meaning of the present invention are understood as filter bags which are formed from a first filter bag wall and a second filter bag wall having the same surface such that the two filter bag walls are only joined together at their peripheral edges (the term “same surface” naturally does not exclude the fact that the two individual layers differ from one another in that one of the layers has an inlet opening).

The two filter bag walls can be joined by a welded seam or a bonded seam along the entire periphery of the two filter bag walls; however, the join can also be formed in that a single layer of filter material is folded around one of its axes of symmetry and the remaining open peripheral edges of the two filter bag walls produced thus are welded or bonded (a so-called tubular bag). Accordingly, three welded seams or bonded seams are required in this type of production. Two of these seams then form the edge of the filter bag, the third welded seam can also form an edge of a filter bag or can be located in one of the filter bag walls. A filter bag wall, seen individually, can consist of one or more layers in this case which can be laminated, for example.

Flat bags within the meaning of the present invention can also have so-called side folds. These side folds can be fully folded out in this case. A flat bag having side folds of this type is shown, for example, in DE 20 2005 000 917 U1 (see therein Fig. 1 having folded-in side folds and Fig. 3 having folded-out side folds). Alternatively, the side folds can be welded with parts of the peripheral edge. A flat bag of this type is shown in DE 10 2008 006 769 A1 (see in particular Fig. 1 therein).

It inevitably follows from the above definition of the term “flat bag” that, immediately after production, flat bags are two-dimensional structures, i.e. before they are used they have an internal volume which is substantially equal to zero.

However, a filter bag having an internal volume which (before use) is substantially equal to zero is not necessarily a flat bag within the meaning of the present invention. Bag forms which have a bottom, as shown for example in DE 20 2005 016 309 U1 or in DE 20 2009 004 433 U1 are not flat bags because they do not consist of two single layers which have the same surface and are only joined together at their peripheral edges.

In view of the above definition, it is clear that bag forms which are already three-dimensional structures after production and thus have an internal volume other than zero, as shown for example in WO 00/00269 (see therein Fig. 27 and 28) and in DE 10 2007 060 748 (see therein particularly Fig. 9) are not flat bags within the meaning of the present invention. A nonwoven filter bag within the meaning of the present invention comprises a nonwoven filter material. A dry-laid or wet-laid nonwoven or an extruded nonwoven, in particular a melt-spun microfibre spunbonded nonwoven (meltblown nonwoven) or a filament spunbonded nonwoven can be used as the nonwoven material. In addition, nanofibre layers can also be present. The distinction between wet-laid nonwovens and conventional wet-laid paper is made according to the definition provided below, as is also used by the EDANA (International Association Serving the Nonwovens and Related Industries). Thus conventional (filter) paper is not a nonwoven.

The nonwoven can comprise staple fibres or continuous fibres. In terms of production, a plurality of layers of staple fibres or continuous fibres can also be provided which are bonded to form just one nonwoven layer.

The filter material can also be a laminate of a plurality of nonwoven layers, such as filament spunbonded nonwoven and meltblown nonwoven (SMS, SMMS or SnxMS). A laminate of this type can be laminated using a hot-melt adhesive or calendered. The layer of meltblown nonwoven can be creped.

The term “nonwoven” is used according to the definition in accordance with ISO standard ISO 9092: 1988 or standard EN 29092. In particular, the terms “fibrous web” or “web” and “nonwoven” are distinguished from one another in the field of nonwoven production as follows and are also to be understood in this manner within the meaning of the present invention. Fibres and/or filaments are used to produce a nonwoven. The relaxed or loose and still unbound fibres and/or filaments are known as a web or fibrous web. From a fibrous web of this type, in a so-called web bonding step, a nonwoven is finally produced which is strong enough to be wound up into rolls, for example. In other words, a nonwoven is formed in a self-supporting manner by bonding. (Details concerning the use of the definitions and/or methods described herein can also be found in the standard reference “Vliesstoffe” [Nonwovens], W. Albrecht, H. Fuchs, W. Kittelmann, Wiley-VCH, 2000).

The first filter bag wall has at least two surface folds. The manner in which surface folds of this type can be formed is described, for example in European patent application EP 2 366 321 (see therein particularly Fig. 10a and Fig. 10b and Fig. 11a and Fig. 11b, respectively). If the filter bag wall comprises a plurality of surface folds, this material is also known as pleated filter material. Pleated filter bag walls of this type are disclosed in European patent application EP 2 366 319.

Fig 1 and 2 are cross-sectional views of a filter bag having a first filter bag wall, each filter bag wall having two surface folds. Surface folds of this type increase the filter surface area of the filter bag, thereby providing a greater dust absorption capacity of the filter bag with a greater separation efficiency and a longer service life (in each case compared to a filter bag having the same external dimensions without surface folds).

Fig. 1 shows a filter bag having a first filter bag wall 10 which has two surface folds 11 in the form of so-called dovetail folds. Here, the filter bag is shown in cross section through the centre of the filter bag. Thus, the longitudinal axes of the surface folds extend in a plane vertical to the plane of the drawing and the surface folds merge at their longitudinal ends into the welded seams of the filter bag which extend in parallel with the plane of the drawing and lie upstream and downstream of the plane of the drawing. The surface folds can thus be unfolded to the greatest degree in the centre thereof. Here, the filter bag is shown in a state in which the surface folds are already slightly unfolded. Each dovetail fold 11 has regions 11 a located in the surface of the filter bag wall 12 and regions 11 b which project beyond the surface of the filter bag wall 12. When the filter bag is inserted for the first time into the vacuum cleaner device, these regions 11b have not yet unfolded.

Fig. 2 shows a filter bag having a first filter bag wall 20 which has two surface folds 21 in the form of so-called triangular folds. The filter bag is also shown here in cross section through the centre of the filter bag. Accordingly, the longitudinal axes of the surface folds extend in a plane which, for its part, extends so as to be vertical to the plane of the drawing and the surface folds merge at their longitudinal ends into the welded seams of the filter bag which extend in parallel with the plane of the drawing and lie upstream and downstream of the plane of the drawing. The surface folds can thus unfold to the greatest degree in the centre thereof. Here, the filter bag is also shown in a state in which the surface folds are already slightly unfolded. Each triangular fold 21 has regions 21a located in the surface of the filter bag wall 22 and regions 21b which project beyond the surface of the filter bag wall 22. When the filter bag is inserted for the first time into the vacuum cleaner device, these regions 21b have not yet unfolded.

In addition to the surface folds shown in Fig 1 and 2, surface folds having other forms are also possible. The fact that the surface folds in the embodiments according to Fig. 1 and 2 extend so as to be vertical to an edge of the bag should not be understood as a restriction. The surface folds can naturally also extend at an angle to the edges of the bag.

The second filter bag wall of the filter bag shown in Fig. 1 and 2 does not have any surface folds. This second filter bag wall can naturally also have one or more surface folds.

Although filter bags having surface folds have a high dust absorption capacity with a higher separation efficiency and a longer service life compared to filter bags of the same external dimensions without surface folds, it has been found that the surface folds of such filter bags are often unable to fully unfold in filter bag receiving spaces of conventional vacuum cleaner devices and consequently the high dust absorption capacity inherent in the filter bag cannot be fully utilised.

DESCRIPTION OF THE INVENTION

Therefore, the object of the invention is to provide a filter bag having surface folds, in which filter bag the high dust absorption capacity inherent in the filter bag with a high separation efficiency and a long service life can also be fully utilised with conventional vacuum cleaner devices.

This object is achieved by a vacuum cleaner filter bag according to claim 1, i.e. by a filter bag which is configured as a nonwoven filter bag, as a disposable filter bag and as a flat bag having a first filter bag wall and a second filter bag wall and comprises at least two surface folds in the first filter bag wall, each surface fold having regions located in the surface of the first filter bag wall and regions which project beyond the surface of the first filter bag wall and can unfold during suction operation, and has a filter bag wall connection means which is provided inside the vacuum cleaner filter bag and joins the first filter bag wall in the region of the surface fold located in the first filter bag wall, to the second filter bag wall and/or joins the first filter bag wall in the region which projects beyond the surface of the first filter bag wall and can unfold during suction operation, to the second filter bag wall.

Since the first and second filter bag walls are joined together, the manner in which the surface folds of the filter bag unfold during suction operation is predetermined. By appropriately adjusting the distance achievable by the filter bag wall connection means, the filter bag can thus be adapted to the filter bag receiving space in a vacuum cleaner device so that the surface folds unfold in an optimum manner. A development of the previously described invention provides a filter bag in which provided in the longitudinal direction of the surface fold in the region which is located in the first filter bag wall and/or in the region which projects beyond the surface of the first filter bag wall and can unfold during suction operation are one or more further filter bag wall connection means which joins or join the first filter bag wall to the second filter bag wall. This development provides a further improvement in the unfolding of the surface folds of the filter bag, since as a result the unfolding can be managed in a more controlled manner. A further development of the previously described invention provides a filter bag comprising at least one surface fold in the second filter bag wall, each surface fold in the second filter bag wall having regions located in the surface of the second filter bag wall, and having regions which project beyond the surface of the second filter bag wall and can unfold during suction operation, and the at least one filter bag wall connection means joins/join the first filter bag wall to the second filter bag wall in a region located in the surface of the second filter bag wall or in a region which projects beyond the surface of the second filter bag wall and can unfold during suction operation. A filter bag of this type exhibits an even higher dust absorption capacity with an even higher separation efficiency and an even longer service life.

According to a development of the previously described invention, each filter bag wall connection means is provided as a distance restricting means so that it restricts the distance between the regions in the first filter bag wall and the regions in the second filter bag wall in which the corresponding distance restricting means is provided.

For this purpose, all the distance restricting means can be provided in the form of a web strip which is provided with incisions of different lengths and is joined to the first filter bag wall in the regions of the surface fold which are located in the first filter bag wall or in the regions which project beyond the surface of the second filter bag wall and can unfold during suction operation, and is joined to the second filter bag wall in the regions, opposite these regions, of the second filter bag wall. In this manner, the distance restricting means can be realised particularly simply in terms of production. Due to the incisions which are of different lengths in the longitudinal direction of the surface fold, different distances can be realised between the first and second filter bag walls according to the length.

Alternatively, each distance restricting means can be provided in the form of a thread, in particular a basting thread, or a web strip. Particularly in the case of a thread, care must be taken that if the thread passes through the filter bag wall, the wall is resealed at this passage site, for example by sealing the passage point using hotmelt adhesive.

The distance restricting means can also be provided in the form of a knitted spacer fabric which is arranged between the first and second filter bag walls and adjusts the desired distance between the two filter bag walls. A knitted spacer fabric is known per se from DE 10 2009 038230.

According to another development of the invention, each filter bag wall connection means can also be provided in the form of a welded surface and/or bonded surface which directly joins the first and second filter bag walls together. As a result, the first and second filter bag walls are not kept at a distance from one another. This development can be realised very simply in terms of production and therefore constitutes an extremely economical compromise in respect of the previously described distance restricting means for some filter bag receiving spaces.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings explain the prior art and the invention. In the drawings:

Fig. 1 shows a filter bag according to the prior art having two surface folds in the form of dovetail folds;

Fig. 2 shows a filter bag according to the prior art having two surface folds in the form of triangular folds;

Fig. 3 shows a first embodiment of the present invention;

Fig. 4 shows a second embodiment of the present invention;

Fig. 5 shows a third embodiment of the present invention; and

Fig. 6 shows a fourth embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Fig. 3 is a sectional view of a first embodiment of the present invention through the centre of the filter bag. The filter bag has a first filter bag wall which has two surface folds in the form of dovetail folds 31. The second filter bag wall does not have any surface folds. In the view of Fig. 3, the surface folds are not yet fully unfolded.

The surface folds have regions 31a which are located in the surface of the filter bag wall 32 and regions 31 b which project beyond the surface of the filter bag wall 32. In the embodiment shown in Fig. 3, the first filter bag wall in the region 31 b is joined to the second filter bag wall by a distance restricting means 35 in the form of a basting thread. Since the surface fold is not yet fully unfolded, this basting thread is not yet under tension. Therefore, the surface fold can still unfold further until it is prevented from doing so by the basting thread. Adjusting the length of the distance restricting means thus ensures an optimum unfolding procedure.

In addition to the distance restricting means shown in Fig. 3, further distance restricting means, also in the form of basting threads, can be provided along the surface fold. These distance restricting means will necessarily keep the first and second filter bag walls at a shorter distance from one another than the central distance restricting means.

Fig. 4 shows a second embodiment of the present invention. This embodiment corresponds to the embodiment shown in Fig. 3 with the difference that the distance restricting means is not fastened to the first filter bag wall in the region 41b, but in the region 41a which is located in the surface of the filter bag wall.

Fig. 5 shows a third embodiment according to the present invention. In this embodiment, the second filter bag wall also has two surface folds in the form of dovetail folds. The first and second filter bag walls are joined together by a distance restricting means which is respectively located in the regions 511 and 512, located in the surface of the corresponding filter bag wall 52-i and 522.

Fig. 6 is a plan view of a fourth embodiment of the present invention. According to this embodiment, the first filter bag wall has two surface folds in the form of dovetail folds. The edges of the dovetail folds, visible in the plan view, are shown by a solid line and the edges which cannot be seen in the plan view are shown accordingly by dashed lines. According to this embodiment, the first and second filter bag walls are joined together by welded dots or bonded dots S provided in the regions 61a which are located in the surface of the filter bag wall.

According to Fig. 6, the joining sites are in the form of dots. Alternatively, any other forms of joining surfaces can also be used.

In a further embodiment of the invention which is not shown, all the distance restricting means are realised by a web strip which has incisions of different lengths and which extends in parallel with the corresponding surface fold.

In another embodiment, also not shown, all the distance restricting means are realised by a knitted spacer fabric.

Claims

A vacuum cleaner filter bag designed as a nonwoven filter bag, as a one-way filter bag, and as a flat bag with a first filter bag wall and with a second filter bag wall, the vacuum cleaner filter bag having at least two surface folds (31) in the first filter bag wall, each surface fold (31) having areas ( 31a), which lies in the surface of the first filter bag wall (32), and has areas (31b) which extend beyond the surface of the first filter bag wall (32) and can be unfolded by suction operation, and a filter bag wall connection device provided within the vacuum cleaner the filter bag and connects the first filter bag wall in the area (31a) at the surface fold (31), which area lies in the first filter bag wall, with the second filter bag wall and / or connects the first filter bag wall in the area (31b) which extends beyond the surface of the first filter bag wall and can be unfolded by suction operation, with the second filter bag wall.

A filter bag according to claim 1, in which in a longitudinal direction of the surface fold (31) in the region (31a) which lies in the first filter bag wall and / or in the region extending beyond the surface of the first filter bag wall (32) and can be unfolded by suction operation, one or more additional filter bag wall connecting devices are provided, which filter bag wall connecting device or filter bag wall connecting devices connect the first filter bag wall with the second filter bag wall.

Filter bag according to one of the preceding claims, which has at least one surface fold (31) in the second filter bag wall, wherein each surface fold (31) in the second filter bag wall has areas which lie in the surface of the second filter bag wall and have areas which protrudes beyond the surface of the second filter bag wall and can be unfolded by suction operation, and the at least one filter bag wall connection device connects the first filter bag wall with the second filter bag wall in an area which lies in the surface of the second filter bag wall or in a projecting area. above the surface of the second filter bag wall and can be unfolded by suction operation.

Filter bag according to one of the preceding claims, in which each filter bag wall connection device is provided as a distance limiting device (35) which limits the distance between the areas of the first filter bag wall and the areas of the second filter bag wall, in which areas the corresponding distance limiting device (35) is provided.

A filter bag according to claim 4, in which all the distance limiting devices (35) are provided in the form of a nonwoven strip having different length incisions, which web strip in the region of the surface fold (31), which is located in the first filter bag wall, or in the areas which extend beyond the surface of the second filter bag wall and can be unfolded by suction operation are connected to the first filter bag wall, and in the regions of the second filter bag wall which are opposite these areas are connected to the second filter bag wall.

A filter bag according to claim 4, in which each distance limiting device (35) is provided in the form of a thread, in particular a staple thread or a nonwoven strip.

A filter bag according to claim 4, in which all the spacer restriction devices (35) are provided in the form of a spacer disposed between the first and second filter bag walls.

A filter bag according to any one of claims 1 to 3, in which each filter bag wall connection device is provided in the form of a welding surface and / or adhesive surface which connects the first and second filter bag walls directly to each other.