Vacuum cleaner filter bag

Abstract

The invention relates to a vacuum cleaner filter bag comprising a first bag wall (104) comprising a filter material and a second bag wall also comprising a filter material and a base (103). The first and the second bag wall are joined to the base along one part of the periphery thereof and are joined together along the remaining part of the periphery. The connection between the first bag wall, the second bag wall and the base is formed such that the vacuum cleaner filter bag is completely closed. The filter material of the first and the second bag walls is made of non-woven material. Said vacuum cleaner filter bag comprises an opening (102) through which the air which is to be filtered can pass through into the vacuum cleaner filter bag, and a retaining plate. Said vacuum cleaner filter bag is characterised in that the first and/or the second bag wall comprises at least five folds (101).

Claims

1. A vacuum cleaner filter bag having a first bag wall comprising a filter material and a second bag wall comprising a filter material and a base, wherein the first and the second bag wall are each joined to the base along one part of their periphery and are joined together along the remaining part of their periphery, wherein a connection between the first bag wall, the second bag wall and the base is formed such that the vacuum cleaner filter bag is completely closed, wherein the filter material of the first and of the second bag wall is made of 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, and a retaining plate, and wherein the first or the second bag wall has at least five folds that form surface foldings; 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 the 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 the 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 the base comprises filter material or the retaining plate.

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

4. The vacuum cleaner filter bag according to claim 1, wherein the maximum height of the surface foldings before a first operation of the vacuum cleaner filter bag in a vacuum cleaner is less than the maximum width of the surface foldings corresponding to the maximum height.

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 length that is greater than one-third of the total extension of the vacuum cleaner filter bag in the direction of the fold.

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 height between 3 mm and 100 mm.

7. 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.

8. 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.

9. 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.

10. The vacuum cleaner filter bag according to claim 1, further comprising at least one side folding that is formed by the first or the second bag wall.

11. The vacuum cleaner filter bag according to claim 10, wherein the at least one side folding itself has at least one fold.

12. The vacuum cleaner filter bag according to claim 11, wherein the at least one fold runs at an angle greater than 45 to the side folding.

13. 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.

14. 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.

15. 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.

16. 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.

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

18. The vacuum cleaner filter bag according to claim 1, wherein the fixing device comprises at least one nonwoven material strip.

19. A vacuum cleaner filter bag comprising: a first bag wall comprising a filter material; a second bag wall comprising a filter material; a base; an inlet opening, through which the air to be cleaned can flow into the vacuum cleaner filter bag; and a retaining plate; wherein the first and the second bag wall are each joined to the base along one part of their periphery and are joined together along the remaining part of their periphery, wherein a connection between the first bag wall, the second bag wall and the base is formed such that the vacuum cleaner filter bag is completely closed, wherein the filter material of the first and of the second bag wall is made of a nonwoven, wherein the first or the second bag wall has at least five folds and further comprising at least one side folding that is formed by the first or the second bag wall and itself has at least one fold that runs at an angle greater than 45 to the side folding; 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 the 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 the at least five folds on an exterior of the vacuum cleaner filter bag is free from any fixing device.

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 an inner face of an exemplary vacuum cleaner filter bag;

(4) FIG. 3 a diagonal view of an inner face 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 side fold;

(10) FIG. 9 an illustrative diagram in which the volume flow through the bag wall of an exemplary vacuum cleaner filter bag and of a vacuum cleaner filter bag according to the state of the art is depicted in dependency on the dust mass stored therein;

(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 that comprises a first bag wall 104 and a second bag wall which is concealed by the first bag wall. The first and the second bag wall are connected to each other by means of three weld seams 120, 130, and 140. The vacuum cleaner filter bag furthermore comprises a base 103 which has the form of a retaining plate in the present design. This base 103 is connected to the first bag wall by means of a first adhesive seam and to the second bag wall by means of a second adhesive seam; the adhesive seams are located on the not visible back side of the retaining plate and are therefore indicated by an arrow 110a for the first adhesive seam and an arrow 110b for the second adhesive seam.

(16) The vacuum cleaner filter bag according to 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. The retaining plate is used to fix the vacuum cleaner filter bag in a chamber of a vacuum cleaner and it has a through hole in the area of the inlet opening 102.

(17) The folded nonwoven material comprises a plurality, particularly more than two, foldings 101. The foldings 101 are formed here as reclining foldings. A reclining folding is obtained by allowing the height H.sub.max of the folding shown in FIG. 13b to approach zero. Naturally other foldings are possible, particularly upright foldings, as they are described in the following or as they are shown in FIGS. 13a to 13c.

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

(19) Although the base 103 is provided in the form of a retaining plate in the design according to FIG. 1, it can alternatively also comprise filter material in order to increase the total filter area, whereby the retaining plate is mounted on the filter material in a known manner, for example, by gluing. The filter material of the base can, but does not have to, likewise have foldings.

(20) In the designs shown in FIG. 1, the foldings run crosswise to the longitudinal axis of the vacuum cleaner filter bag. It is alternatively also possible to have the foldings run parallel or at an angle to this longitudinal axis.

(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. In other words, the fold width of the folds 201 is fixed 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.

(22) 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.

(23) 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 airlaid nonwoven. The material strips 205 can also comprise a laminate of a plurality of nonwovens, particularly a laminate of spunbond nonwoven-meltblown nonwoven-spunbond nonwoven.

(24) 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.

(25) 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.

(26) The material strips 205 can also have 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 extension 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.

(27) 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).

(28) 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.

(29) 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 nonwoven material 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.

(30) 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.

(31) FIG. 4 furthermore shows the fold width W.sub.max and the fold height H.sub.max of the foldings. The fold height h and/or the fold width w 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 legs has an angle of roughly 116.

(32) 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.

(33) 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.

(34) 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.

(35) 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.

(36) 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.

(37) 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.

(38) 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 localizing device 705.

(39) FIG. 8 shows an exemplary vacuum cleaner filter bag in a top view onto an outer side of the vacuum cleaner filter bag. The vacuum cleaner bag has an upper or first bag wall 804 and a lower or second bag wall 805. The vacuum cleaner filter bag furthermore has a base 803 that is formed as a retaining plate and that has an inlet opening 802. The upper bag wall 804 and the lower bag wall 805 are connected by three weld seams, of which two are visible in FIG. 8. These are indicated with the reference numbers 820 and 830.

(40) The vacuum cleaner filter bag has a side folding 813 in the area of the weld seam 830. There is also correspondingly a further side folding, lying opposite the weld seam 813, in the area of the weld seam that is not visible.

(41) The upper bag wall 804 and the lower bag wall 805 comprise a multiplicity of reclining foldings 801. Foldings 811 are likewise provided in the area of the side foldings (see particularly at 813). These foldings 811 are here likewise reclining foldings and run essentially at a right angle to the closure of the side folding.

(42) According to an embodiment that is not shown, the side foldings can also have an unfolded filter material. In particular, in such an embodiment the foldings could also run parallel to the longitudinal axis of the bag.

(43) In FIGS. 4 to 7 the foldings have the shape of a triangle, but the foldings can also have any other shape. 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.

(44) 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 dovetail 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.

(45) 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.

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

(47) 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.

(48) 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 reclining 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.

(49) 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.

(50) 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.

(51) 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.

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

(53) 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.

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

(55) 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.

(56) 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.

(57) Measurement Results

(58) FIG. 9 is used for illustration purposes, and shows a diagram in which the volume flow through the vacuum cleaner (Vorwerk VK 140) is depicted in dependence of the dust load (DMT-8 dust) in grams. Each of the bag walls consists of 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).

EXAMPLE 1

(59) Block bottom bag according to the state of the art (without surface foldings). The shape of this vacuum cleaner filter bag is the same as the shape of the vacuum cleaner filter bag shown in FIG. 8. The vacuum cleaner filter bag according to Example 1 has no surface foldings, however. In addition, the base comprises filter material without surface foldings, in addition to the retaining plate. The width of the vacuum cleaner filter bag amounts to 140 mm (corresponds to the width along the weld seam 820 in FIG. 8). The length of the vacuum cleaner filter bag (corresponds to the length along the upper bag wall from the retaining plate to the weld seam) amounts to 240 mm. The height of the vacuum cleaner bag in the area of the base amounts to 85 mm. The retaining plate measures roughly 65 mm70 mm.

EXAMPLE 2

(60) Block bottom bag with surface foldings in dovetail form. The vacuum cleaner filter bag has the same shape and size as Example 1. In contrast to this, however, the bag's upper side and the bag's lower side each has three dovetail folds with a first leg with a length of 15 mm, a second leg, running parallel to the bag wall, with a length of 40 mm and a third leg again with a length of 15 mm. In contrast, the base has no surface foldings.

(61) 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.

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

(63) 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 spunbond (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).

(64) 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

(65) 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.

(66) 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.

(67) 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.

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