Vacuum cleaner filter bag

Abstract

The invention relates to a vacuum cleaner filter bag, including a first bag wall containing a filter material and a second bag wall containing a filter material. The first and the second bag walls are joined together along the periphery thereof such that the vacuum cleaner filter bag is completely closed. The filter material of the first and the second bag walls is made of a non-woven fabric. The vacuum cleaner filter bag includes an inlet through which the air which is to be filtered can flow into the vacuum cleaner filter bag, also including a retaining plate. The vacuum cleaner filter bag is characterized in that the first and/or the second bag wall includes at least five folds.

Claims

1. A vacuum cleaner filter bag with a first bag wall comprising a filter material and a second bag wall comprising a filter material, wherein the first and the second bag wall are connected to each other along their periphery such that the vacuum cleaner filter bag is completely closed, wherein the filter material of the first and of the second bag wall is formed from a nonwoven, wherein the vacuum cleaner filter bag has an inlet opening, through which the air to be cleaned can flow into the vacuum cleaner filter bag, the inlet opening is positioned on a surface of the first or the second bag wall, and a retaining plate, and wherein the first or the second bag wall has at least five folds; and further comprising a fixing device that prevents at least one of the at least five folds from unfolding completely and wherein the fixing device is arranged on a first side of the bag wall having at least five folds that is facing towards an interior of the vacuum cleaner filter bag and a second side of the bag wall having at least five folds on an exterior of the vacuum cleaner filter bag is free from any fixing device.

2. The vacuum cleaner bag according to claim 1, wherein fold legs of the at least five folds have inflection lines that run essentially straight.

3. The vacuum cleaner filter bag according to claim 1, wherein the at least five folds form at least one surface folding, wherein a maximum height of the surface folding before a first operation of the vacuum cleaner filter bag in a vacuum cleaner is less than a maximum width of the surface folding corresponding to the maximum height.

4. The vacuum cleaner filter bag according to claim 1, wherein before a first operation of the vacuum cleaner filter bag in a vacuum cleaner, each of the at least five folds has a length that is greater than one-third of a total extension of the vacuum cleaner filter bag in a direction of the fold.

5. The vacuum cleaner filter bag according to claim 1, wherein before a first operation of the vacuum cleaner filter bag in a vacuum cleaner, each of the at least five folds has a height between 3 mm and 100 mm.

6. The vacuum cleaner filter bag according to claim 1, wherein before a first operation of the vacuum cleaner filter bag in a vacuum cleaner, each of the at least five folds has a width between 3 mm and 100 mm.

7. The vacuum cleaner filter bag according to claim 1, wherein at least two of the at least five folds have heights or widths or shapes that differ from one another.

8. The vacuum cleaner bag according to claim 1, wherein a plurality of folds are provided that are distributed essentially uniformly across the first or the second bag wall.

9. The vacuum cleaner filter bag according to claim 1, furthermore comprising at least one side folding.

10. The vacuum cleaner filter bag according to claim 1, wherein the fixing device is glued or welded to the at least one fold or to the bag wall adjacent to the at least one fold.

11. The vacuum cleaner filter bag according to claim 1, wherein the fixing device comprises at least one material strip or wherein the fixing device has a predetermined expansion behaviour or a predetermined elastic behaviour.

12. The vacuum cleaner filter bag according to claim 1, wherein the fixing device is a nonwoven material layer, a net layer, a perforated foil or a fabric ply that extends across the entire first or second bag wall.

13. The vacuum cleaner filter bag according to claim 1, wherein fibers or absorbents are provided in a hollow space that is formed by the fixing device and fold legs of the at least one fold.

14. The vacuum cleaner filter bag according to claim 1, comprising installation space utilization during operation that is greater than 65%.

15. The vacuum cleaner filter bag according to claim 1, wherein before a first operation of the vacuum cleaner filter bag in a vacuum cleaner, each of the at least five folds has a length that corresponds to the total extension of the bag in a direction of the fold.

16. The vacuum cleaner filter bag according to claim 1, wherein before a first operation of the vacuum cleaner filter bag in a vacuum cleaner, each of the at least five folds has a width between 5 mm and 15 mm.

Description

DESCRIPTION OF THE FIGURES

(1) Further characteristics and advantages of the invention are explained in the following on the basis of explanatory figures. Shown are:

(2) FIG. 1 an exemplary vacuum cleaner filter bag;

(3) FIG. 2 a diagonal view of the interior of an exemplary vacuum cleaner filter bag;

(4) FIG. 3 a diagonal view of an interior of a further exemplary vacuum cleaner filter bag;

(5) FIG. 4 a cross-section through a subarea of an exemplary vacuum cleaner filter bag;

(6) FIG. 5 a cross-section through a subarea of a further exemplary vacuum cleaner filter bag;

(7) FIG. 6 a cross-section through a subarea of a further exemplary vacuum cleaner filter bag;

(8) FIG. 7 a cross-section through a subarea of a further exemplary vacuum cleaner filter bag;

(9) FIG. 8 a further exemplary vacuum cleaner filter bag with a side folding;

(10) FIG. 9 an illustrative diagram in which the volume flow through the bag wall of exemplary vacuum cleaner filter bags in dependence on the dust mass stored therein is depicted;

(11) FIGS. 10a and 10b a cross-section through a subarea of an exemplary vacuum cleaner filter bag;

(12) FIGS. 11a and 11b a cross-section through a subarea of a further exemplary vacuum cleaner filter bag;

(13) FIGS. 12a to 12c a cross-section through side foldings according to the state of the art; and

(14) FIGS. 13a to 13d a cross-section through various foldings for explanation of the terms maximum fold height and maximum fold width.

DETAILED DESCRIPTION OF THE INVENTION ON THE BASIS OF PREFERRED EXAMPLES

(15) FIG. 1 shows an exemplary vacuum cleaner filter bag in the form of a flat bag in which one side is shown opened for purposes of illustration. In fact, a weld seam is to be found in the area of the side that is shown here opened.

(16) The exemplary vacuum cleaner filter bag of FIG. 1 comprises a first and a second bag wall of folded nonwoven material. The first and the second bag wall are connected to each other by means of four weld seams. FIG. 1 shows three of these four weld seams 120, 130, and 140. The folded nonwoven material comprises a plurality of, particularly more than two, folds 101. The folds 101 here form upright foldings.

(17) The exemplary vacuum cleaner filter bag of FIG. 1 furthermore comprises an inlet opening 102 through which the air that is to be cleaned can flow into the vacuum cleaner filter bag, as well as a retaining plate 103 that is used to fix the vacuum cleaner filter bag in a chamber of a vacuum cleaner, and that has a through hole in the area of the inlet opening 102.

(18) The folds 101 in the exemplary vacuum cleaner filter bag of FIG. 1 are formed along the entire length of the vacuum cleaner filter bag. Depending on the orientation of the retaining plate 103, the vacuum cleaner filter bag can have a long side and a broad side. The folds 101 can extend along the long side or along the broad side, particularly along the entire long side or broad side.

(19) In the case of the exemplary vacuum cleaner filter bag of FIG. 1, an area 104 of the bag wall is free of folds. Alternatively, folds of the first and/or of the second bag wall can, however, also be located on the entire bag wall.

(20) The bag wall can particularly have two or more filter layers, whereby at least one layer comprises the folded nonwoven material.

(21) FIG. 2 shows a diagonal view of an interior of a bag wall of an exemplary vacuum cleaner filter bag. In this example, the folds 201 of the nonwoven material are connected to one another by means of a fixing device in the form of a plurality of material strips 205. In particular, the folds 201 are held at a predetermined distance from one another by means of the material strips 205.

(22) In other words, the fold width of the folds 201 is set by the material strips 205. The material strips 205 are connected, for example, glued or welded, to the folds 201, particularly to an edge of the folds 201, at connection points 206. The arrow 210 indicates the flow direction of the air to be cleaned through the nonwoven material.

(23) The material strips 205 can, for example, have a width of from 0.5 cm to 4 cm, particularly from 1 cm to 3 cm, for example, 2 cm.

(24) The material strips 205 can comprise a nonwoven material. In particular, the nonwoven material can comprise an extrusion nonwoven, for example, a spunbond nonwoven and/or a carded or air-laid nonwoven. The material strips 205 can also comprise a laminate of a plurality of nonwovens, particularly a laminate of spunbond nonwovenmeltblown nonwovenspunbond nonwoven.

(25) The mass per unit area of the material strips 205 can be less than 250 g/m.sup.2, particularly between 10 g/m.sup.2 and 30 g/m.sup.2.

(26) Some of the connection points 206 can be formed in such a way that the connection detaches during the operation of the vacuum cleaner filter bag. The flow behaviour of the air flowing into the bag can be influenced by means of the at least partially detached material strips 205.

(27) The material strips 205 can also have a predetermined expansion behaviour. In this way, it is possible to achieve a predetermined expansion of the bag during operation. The material strips 205 can also have elasticity, so that the expansion of the bag can be reduced by elastic restoring forces again after operation, meaning after the vacuum cleaner has been switched off. In this way, dust can also be conveyed from the bag wall into the interior of the vacuum cleaner filter bag.

(28) Alternatively to a plurality of material strips 205, the fixing device can also be formed as a material strip across the entire surface. In this case, the fixing device can have a high level of air permeability, particularly more than 5000 l/(m.sup.2 s).

(29) The fixing device can also comprise an air-permeable paper, weave and/or a foil. To increase the air permeability, the fixing device can also be perforated or slit.

(30) FIG. 3 shows a diagonal view of an interior of a bag wall of a further exemplary vacuum cleaner filter bag. In this case, the fixing device is formed in the form of a net 307 that connects the folds 301 of the pleated nonwoven material to one another in a subarea of the surface. In other areas of the surface, the folds of the first and/or of the second bag wall are not connected by the fixing device. By means of a partial fixing of the folds of this kind, it is possible to achieve an optimal fitting of the vacuum cleaner filter bag to the installation space of the vacuum cleaner during operation. The arrow 310 indicates the direction of flow through the nonwoven material of the air that is to be cleaned.

(31) FIG. 4 shows a cross-section through a subarea of the bag wall of an exemplary vacuum cleaner filter bag, whereby the cross-section runs perpendicularly to the run of the folds of the first and/or of the second bag wall. In particular, FIG. 4 shows a zigzag folding comprised of three foldings 401 that comprises seven folds I-VII. The folds I, III, V and VII are connected to one another by means of a fixing device 405. In particular, the fixing device 405 is connected to the fold closures of these folds at connection points 406. The arrow 410 indicates the direction of flow of the air that is to be cleaned to the bag wall. In this example, the fixing device 405 is consequently on the upstream side with reference to the bag wall.

(32) FIG. 4 furthermore shows the fold width W.sub.max and the fold height H.sub.max of the foldings. The fold height and/or the fold width can lie between 3 mm and 100 mm, particularly between 5 mm and 15 mm. The foldings are upright foldings; the one part of the fold leg hereby has an angle of roughly 64, and the other part of the fold leg has an angle of roughly 116.

(33) FIG. 5 shows a further cross-section through a part of a bag wall of an exemplary vacuum cleaner filter bag. In particular, shown in the detail are two foldings 501 made of six folds I-VI, and a fixing device 505 arranged on the upstream side with regard to the direction of flow 510, whereby the fixing device is connected to the folds I, III or IV and VI at the connection points 506.

(34) In FIG. 5, the connection point 506.1 is arranged in the area of the nonwoven material that forms the leg of the folds III and IV and that runs parallel to the bag wall.

(35) The foldings of this vacuum cleaner bag accordingly have legs that run parallel to the bag wall and that lie between the folds that stick out of the bag wall plane. In particular, the width of the parallel leg is hereby less than the width of the opening of the fold that sticks out of the bag wall.

(36) In FIGS. 4 and 5, the foldings have a cross-section in the shape of isosceles triangles. The height of each of these foldings is therefore less than the corresponding width of the foldings.

(37) FIG. 6, for example, shows a cross-section through a subarea of a bag wall of an exemplary vacuum cleaner filter bag, in which the folds 601 have fold leg lengths that are different in the cross-section.

(38) In particular when a full-surface, air-permeable fixing device is used for fixing the folds, the hollow spaces formed between the folds and the fixing device can be filled with fibres, particularly electrostatically charged fibres, and/or with absorbents. For example, coated fibres, activated charcoal and/or porous polymers can be used as absorbents.

(39) FIG. 7 consequently shows a cross-section of a subarea of such a bag wall. In particular, a plurality of folds 701 are shown that form triangular foldings. A fixing device 705 is attached to a part of the folds. Fibres 711 and/or activated charcoal 712 are arranged in the hollow spaces between the fold legs and the fixing device 705.

(40) FIG. 8 shows an exemplary vacuum cleaner filter bag in the form of a flat bag in a top view onto an outer side of the vacuum cleaner filter bag. The upper and the lower bag wall comprise a multiplicity of folds 801. Three weld seams are indicated with the reference numbers 820, 830 and 840. As also in FIG. 1, FIG. 8 depicts a side that is opened for purposes of illustration. In fact, a weld seam, namely the fourth weld seam, is to be found in the area of the side that is shown here opened. The vacuum cleaner filter bag furthermore comprises two side foldings 813 and 814. The filter material is not folded in the area of the side foldings. It is possible for the side folds 813 and 814 to be partially or completely turned out.

(41) According to a design that is not shown, the side foldings can also have folded filter material. In order to keep the folded filter material from unfolding when the side foldings are introduced, it is expedient to provide the side foldings at an angle to the folds that is greater than 45. Assuming the vacuum cleaner filter bag shown in FIG. 8, in this case the side folding would be introduced in the area of the weld seam 820 and/or in the area of the weld seam that is not shown.

(42) In FIGS. 1 and 4 to 8, the folds have a cross-section in the shape of a triangle. The folds can also have any other shape, however. In particular, the shape of the folds in the figures should be seen as only schematic. In particular, the fold legs can also be curved.

(43) The fold shape of one or more folds and/or foldings of the first and/or of the second bag wall can have a dovetail shape perpendicular to the longitudinal axis of the folds in a cross-section. Examples of foldings with a dove tail shape in the cross-section are shown in FIGS. 10a and 10b. The edges 1015 of the fold legs of the folds 1001 that face toward the bag interior are thereby spaced a distance apart from one another. In this way, it is easy for the air that is to be cleaned to penetrate into the folding. The direction in which the air that is to be cleaned flows through the bag wall is illustrated by an arrow 1010.

(44) In FIG. 10a each of the folds 1002 of the nonwoven material is connected, particularly by means of glue and/or welding, to the parallel legs of the folds 1001. The connection points 1016 thereby have a distance from one another in the longitudinal direction of the folds 1002 that is greater than , particularly greater than , of the length of the fold 1002. In this way, the air that is to be cleaned can better flow through the folds 1002 during operation than if there were smaller distances between the connection points 1016.

(45) According to a design that is not shown, the connection points 1016 can also lie on a continuous weld line.

(46) In FIG. 10b, a fixing device 1105 in the form of a plurality of material strips is provided that is glued and/or welded to the at least folded nonwoven material with the fold legs of the folds 1001. A plurality of connection points 1006 are thereby shown in FIG. 10b.

(47) FIGS. 11a and 11b show further exemplary details of a bag wall with a nonwoven material with surface foldings. The foldings, which are formed from the folds 1101, 1102 and 1103 of the nonwoven material, are shown to be reclined in these examples, i.e., the fold legs run essentially parallel to the surface of the bag wall. Because fold legs that run essentially parallel to the surface cannot be drawn, the fold legs here were shown at an angle with reference to the surface of the bag wall.

(48) FIG. 11a furthermore shows a fixing device 1105 that is connected, particularly glued and/or welded, to the nonwoven material that is given surface foldings in areas of the bag wall, whereby these form the fold legs of the folds 1101. The manufacture of the vacuum cleaner filter bag can be simplified by means of this type of connection of the fixing device. In particular, a plurality of connection points 1106 are shown between the fixing device and the bag wall.

(49) The direction in which the air that is to be cleaned flows through the bag wall is furthermore illustrated in the form of an arrow 1110 in FIGS. 11a and 11b.

(50) The fixing device 1105 is formed across the entire surface in FIG. 11a. The fixing device 1105 could however also be formed in the form of a plurality of material strips, such as is illustrated in FIG. 2.

(51) According to a design that is not shown, the connection points 1106 can also lie on a continuous weld line that preferably runs parallel to the fold axes.

(52) In FIG. 11b, each of the foldings 1101 of the nonwoven material is connected, particularly glued and/or welded, to the fold legs of the folds 1102, which is arranged between two fold edges of the bag wall. The connection points 1116 are thereby spaced apart from one another in the longitudinal direction of the folds 1101 at a distance that is greater than , particularly greater than , of the length of the fold 1101. In this way, the air that is to be cleaned can better flow through the folds 1101 during operation than if the distances between the connection points 1116 were smaller.

(53) According to a design that is not shown, the connection points 1116 can also lie on a continuous weld line that preferably runs perpendicularly to the fold axes.

(54) Due to the use of a nonwoven material with surface foldings, the surface available for filtration can be enlarged given predetermined dimensions of the vacuum cleaner filter bag. This leads to a high filtration performance with a low starting pressure loss. This means a lower media passage speed, which increases the filtration performance, particularly by means of electrostatically-charged fibres of the bag wall.

(55) It shall be understood that characteristics mentioned in the previously described embodiments are not limited to these special combinations and are also possible in any other combinations. In particular, the vacuum cleaner filter bag can be formed with different geometric shapes and/or sizes.

(56) Measurement Results

(57) FIG. 9 is used for illustration purposes, and shows a diagram in which the volume flow through the vacuum cleaner is depicted in dependence of the dust load (DMT-8 dust) in grams. The bag wall is an SMMS laminate, consequently consisting of an outer layer of spunbond (35 g/m.sup.2), two layers of meltblown nonwoven (220 g/m.sup.2) and an inner layer of spunbond (17 g/m.sup.2). The corresponding measurements were made with a Miele S 5210 model vacuum cleaner.

Example 1

(58) Flat bag according to the state of the art. Bag dimensions: 300 mm320 mm.

Example 2

(59) Bag dimensions: (lengthwidth): 300 mm320 mm. Continuous longitudinal folds, uniformly distributed across the surface, were present on each the bag upper side and the bag lower side. In particular, the longitudinal folds were provided on each of the bag sides in the form of a zigzag folding, as is shown in FIG. 4 (a fixing device, as is shown in FIG. 4, was not, however, used in this Example 2). The zigzag folding had 20 folds opened towards the vacuum cleaner bag interior. The material width was 630 mm. The average height H.sub.max of the sequence of folds was 12 mm.

Example 3

(60) Bag dimensions (lengthwidth): 300 mm320 mm. The same folding as in Example 2 was provided on the bag upper side and the bag lower side. Additionally, a full-surface fixing device in the form of a net with a mesh width of 5 mm5 mm was present on the interior of the bag upper side and the bag lower side for this bag. This net was attached to the filter medium at 171 points corresponding to FIG. 3.

Example 4

(61) Bag dimensions (lengthwidth): 300 mm320 mm. The same folding as in Example 2 was provided on the bag upper side and the bag lower side. Additionally, a fixing device in the form of nine strips each 20 mm wide was present on the interior of the bag upper side and the bag lower side for this bag. These strips were attached to the filter material at 171 points in accordance with FIG. 2.

Example 5

(62) Bag dimensions (lengthwidth): 300 mm320 mm. The same folding as in Example 2 was provided on the bag upper side and the bag lower side. Additionally, a fixing device in the form of nine strips each 20 mm wide was present on the interior of the bag upper side and the bag lower side for this bag. These strips were attached to the filter material at 171 points in accordance with FIG. 2. An element for flow deflection was additionally present in the bag. This consisted of 14 strips, each 11 mm wide and having a mass per unit area of 110 g/m.sup.2. The strips ran parallel to the folds of the bag upper side and bag lower side.

(63) As can be seen in FIG. 9, the vacuum cleaner filter bags with a bag wall comprising a folded nonwoven material show a greater volume flow even in the case of high dust loads than does a vacuum cleaner filter bag with a bag wall without foldings in the nonwoven material.

(64) In other words, the pressure loss increase of the vacuum cleaner filter bag is reduced due to the greater dust-holding capacity.

(65) Table 1 shows average values (each from five measurements) of the measured pressure loss and of the measured penetration for two different filter media depending on the media passage speed. The high media passage speed hereby corresponds to an unfolded material; the low passage speed corresponds to a folded material. Filter medium 1 is an SMMS laminate made of an outer layer of spunbond (35 g/m.sup.2), two layers of meltblown nonwoven (220 g/m.sup.2) and an inner layer of spunbond (17 g/m.sup.2). Filter medium 2 is an SMMMMS laminate made of an outer layer of spun bond (35 g/m.sup.2), four layers of meltblown nonwoven (419 g/m.sup.2) and an inner layer of spunbond (17 g/m.sup.2).

(66) TABLE-US-00001 TABLE 1 The different media passage speeds were adjusted by changing the volume flow on the TSI 8130. Work was conducted with test samples with a surface area of 100 cm.sup.2. Media passage speed Pressure loss P Penetration TSI 8130 [cm/s] [mm H.sub.2O] [%] Filter medium 1 14.3 14.5 32.2 7.15 6.9 18.7 Filter medium 2 14.3 32.1 0.025 7.15 15.5 0.004

(67) As can be seen in Table 1, the pressure loss and the penetration for the filter medium and flow rate that correspond to a bag wall that has been given folds are considerably less than in the case of the filter medium and flow speed that correspond to the state of the art (unfolded). At the lower media passage speed, the pressure loss for the two observed filter media is only roughly half as great as at the high media passage speed.

(68) For both filter materials, the filtration capacity improves, as expected, considerably at the lower media passage speed. The reduction of the penetration is disproportionately stronger for the filter medium 2 than for the filter medium 1, because in this case the effect of the electrostatic charge of the filter material has an even greater influence than in the case of the more open material 1.

(69) It is possible to achieve an optimal fitting of the vacuum cleaner filter bag to the given installation space in the vacuum cleaner during operation by means of a bag wall with surface foldings. In particular, it is possible to achieve installation space utilization of greater than 65%. In particular, if no fixing device is provided for the folds of the first and/or of the second bag wall, installation space utilization of greater than 80% can be achieved.

(70) Using flat bags such as they are known in the state of the art, normally installation space utilization of only 50% to 65% can be achieved.