EP4058640B1 - Jet regulator - Google Patents

Description

The invention relates to a jet regulator according to the preamble of claim 1, with an outlet structure which has an outlet grid with a regular arrangement of holes and an edge which delimits the outlet grid, wherein holes of the outlet structure which are adjacent to the edge form a ring and delimit a water jet flowing through the outlet structure to the outside, wherein the ring is designed deviating from the regular arrangement.

Such jet regulators are well known and are now made of plastic using injection molding technology. It has become common practice to provide the outlet structure with a regular arrangement of holes, for example a hexagonal arrangement of hexagonal holes, in order to

To form a uniform jet pattern. This regular arrangement is limited by the dimensions of the jet regulator, which can have a round or rectangular or other external contour that differs from the arrangement.

The arrangement of the holes and the clear opening cross-section of the holes are coordinated in such a way that individual jets passing through the holes recombine behind the outlet structure to form a common water jet.

Out of WO 2004/033108 A1 A sanitary fitting is known which has a jet regulating device inside a built-in housing, which
Jet regulating device has at least one insert part which can be inserted into the installation housing and which is transverse to the Has webs oriented in the flow direction, which are limited between passage openings.

Out of EN 10 2017 128758 A1 a sanitary insert unit is known which has a sanitary insert part with an insert housing which has a housing inlet opening into the housing interior on an inflow-side housing front side and which is bordered by a housing peripheral edge, wherein the insert unit is assigned a screen filter which is separate from the insert housing and has a disk-shaped filter head which has an annular disk sub-region on the disk outer circumference, which is designed as a support ring which can be placed on the housing peripheral edge and which filter head has a filter structure in a central disk sub-region which is formed by webs which cross one another at intersection nodes.

Out of EN 10 2006 046245 A1 A jet regulator is known which can be inserted from the outlet front into the water outlet of a sanitary outlet fitting, wherein the jet regulator can be detachably secured or fixed in the water outlet and wherein at least one holding element is provided for securing or fixing the jet regulator in the water outlet, wherein the holding element passes through a passage opening provided on the circumference of the fitting housing and engages the jet regulator in a fixing manner with its end region protruding into the interior of the fitting housing.

The jet regulator can also have a jet regulator housing with a peripheral insertion opening, wherein at least one insertion guide oriented transversely to the jet regulator longitudinal axis is provided in the housing interior of the jet regulator housing and wherein at least one preferably jet-forming insert part can be inserted into the at least one insertion guide from the insertion opening.

The invention is based on the object of improving the jet pattern of such a jet regulator.

To achieve the above-mentioned object, the features of claim 1 are provided according to the invention. Thus, to achieve the above-mentioned object, a jet regulator of the In the manner described at the outset, it is proposed according to the invention that a hole in the ring is enlarged in deviation from the regular arrangement if its clear opening cross-section would otherwise, if the regular arrangement were continued, be less than half as large as the clear opening cross-section of an adjacent hole. The invention makes use of the knowledge that the beam pattern is essentially determined by the partial beams that exit through the holes in the ring. The invention has also recognized that holes in the ring that are too small produce partial beams that do not fully recombine with the other, adjacent partial beams, but have a tendency to form stray beams that branch off to the side. By enlarging these holes that are too small, which entails a deviation from the uniform overall impression of the arrangement, it may be possible to reduce or even completely avoid such stray beams. The beam pattern is thus improved.

The ring can thus be defined as the collection of all those holes of the arrangement continued over the edge that are cut off by the edge.

In an advantageous embodiment, it can be provided that the regular arrangement is formed by holes of the same size and/or the same shape. Thus, a regular arrangement and deviations from such an arrangement are easily recognizable.

In an advantageous embodiment, it can be provided that the ring is designed in a manner deviating from the regular arrangement in that the edge cuts off individual holes in the ring. This means that there is no need to adjust the arrangement to the geometry of the edge.

In an advantageous embodiment, it can be provided that the enlarged hole of the ring is enlarged at the expense of at least one adjacent hole. This provides a simple formation rule for avoiding holes that are too small in the ring.

For example, the adjacent hole can be in the ring. This way, a difference in size between holes within the ring can be compensated.

It can also be provided that the adjacent hole is located inside the outlet structure. This means that holes that are too small can be moved to the inside where they do not cause any interference.

According to the invention, each hole in the ring is enlarged in deviation from the regular arrangement if its clear opening cross-section would otherwise be less than half as large as the clear opening cross-section of an adjacent hole if the regular arrangement were continued. The advantage here is that the formation of interference rays along the entire circumference of the ring can be reduced or even avoided.

In the invention, the jet regulator can be designed as a ventilated or non-ventilated jet regulator.

The outlet structure can, for example, have a round, oval, polygonal, in particular rectangular or square, outer contour.

In an advantageous embodiment, it can be provided that a hole of the ring is enlarged in deviation from the regular arrangement if its clear

Opening cross-section otherwise, if the regular arrangement is continued, from the clear opening cross-section of the neighboring hole deviates by more than 20%. It has been found that such small holes particularly favor the formation of stray rays.

It is particularly advantageous if the hole in the ring is enlarged in a way that deviates from the regular arrangement, if its clear opening cross-section otherwise deviates from the clear opening cross-section of the adjacent hole by more than 15% if the regular arrangement is continued. This makes it possible to achieve the most even distribution of opening cross-sections possible within the ring. This promotes a particularly even design of an outer layer of the water jet and thus a particularly even jet pattern.

In an advantageous embodiment, it can be provided that the holes in the ring have clear opening cross-sections that are at most 50% larger than the clear opening cross-section of a hole inside the outlet structure. The holes inside the outlet structure can thus be used as a reference size. The advantage here is that the formation of holes that are too large in the ring can be avoided.

It is particularly advantageous if the holes in the ring have clear opening cross-sections that are no more than 20%, and in particular no more than 15%, above the clear opening cross-section of a hole inside the outlet structure. This avoids excessive upward deviations in the clear opening cross-sections of the holes in the ring.

It can even be provided that the holes of the ring have clear opening cross-sections that are at or below the clear opening cross-section of a hole inside the outlet structure. This allows a particularly uniform external view of the exiting jet to be achieved.

The mentioned surface proportions can be related to any hole, for example a median or mean value of the opening cross-sections, inside the outlet structure. The surface proportions are preferably related to the largest hole or an uncut hole (i.e., for example, one of the identical holes that make up the arrangement) inside the outlet structure. This allows a natural upper limit to be defined.

In an advantageous embodiment, it can be provided that the clear opening cross-sections of the holes in the ring vary by a maximum of 15%. This means that the partial beams that make up an outer layer of the beam, for example the aforementioned one, can be defined as being as equally large as possible. This enables the beam pattern to be as uniform as possible with as few interfering beams as possible.

In an advantageous embodiment, it can be provided that the outlet structure has at least one rotational symmetry. Thus, a rotational symmetry of the outlet structure, for example a discrete or continuous rotational symmetry, can be transferred to the ring. This promotes a particularly uniform formation of a jet pattern.

Alternatively or additionally, it can be provided that the outlet structure has at least a mirror symmetry. Thus, a mirror symmetry of the outlet structure, for example a planar mirror symmetry, can be transferred to the ring. This promotes a particularly uniform formation of a jet pattern.

Alternatively or additionally, it can be provided that the run-out structure has at least one point symmetry. Thus, a point symmetry of the run-out structure, for example a symmetry that the run-out structure converts into itself by a point reflection at a center, can be transferred to the ring. This promotes a particularly uniform formation of a jet pattern.

In an advantageous embodiment, it can be provided that the outlet structure has a hexagonal arrangement.

In this case or in another embodiment, the edge can be circular. The invention can therefore be used with jet regulators that can be screwed onto a fitting by turning.

In an advantageous embodiment, it can be provided that the outlet structure has at least one hole in the interior, the clear opening cross-section of which is less than 50% of another hole in the ring and/or in the interior. It has been found that the formation of very small holes in the interior does not interfere with the jet pattern, so that other aspects, such as an attractive design or the desire for a characteristic marking, can be taken into account here.

For example, this at least one hole can be arranged in the interior of the outlet structure adjacent to the ring. It is thus possible to enlarge a hole in the ring at the expense of a hole in the interior. The arrangement can otherwise remain unchanged.

For example, the additional hole in the ring or inside the outlet structure can be a largest hole. Thus, a Absolute upper limit for the clear opening cross-sections can be specified.

For example, the additional hole in the ring or inside the outlet structure can be an uncut hole. Thus, dimensioning can be related to identical holes that make up the regular arrangement.

A particularly small impairment of the overall appearance of the outlet structure results if the enlarged hole takes up the shape of the arrangement in at least one (edge) section.

The continuation of the arrangement up to the edge can be made possible, for example, by the holes forming the ring having different clear opening cross-sections.

According to an embodiment essential to the invention, it is provided that at least one hole, which is located inside the outlet structure and is adjacent to a hole in the ring, is trimmed by this hole in the ring in such a way that its (remaining) clear opening cross-section is smaller than that of the untrimmed holes in the regular arrangement. This creates space in a simple way for enlarging a hole in the ring that is too small. The invention has recognized that small holes in the interior, i.e. inside the ring, do not disrupt the jet pattern.

According to an embodiment essential to the invention, it is alternatively or additionally provided that the at least one hole, at the expense of which the hole in the ring was enlarged, has an opening cross-section other than zero. In this way, excessive deviations from the regularity of the arrangement can be avoided.

In an advantageous embodiment, it can be provided that no hole in the ring has a clear opening cross-section that is smaller than half of the clear opening cross-section of the largest and/or uncut holes in the regular arrangement. This makes it easy to avoid beams that are too thin and/or structures that are too fine in the outlet structure.

According to an embodiment essential to the invention, it is alternatively or additionally provided that the hole in the interior, at the expense of which the hole in the ring was enlarged, is combined with another hole in the interior to form a larger hole.

In an advantageous embodiment, it can be provided that a shape and/or an arrangement of enlarged or trimmed holes maintains a rotational symmetry of the regular arrangement. In this way, a pleasing and/or attractive design can be achieved.

In an advantageous embodiment, it can be provided that a width of the ring is limited by a largest clear dimension of a largest and/or uncut hole in the arrangement, in particular in the interior. A natural scale of the outlet structure can thus be used to dimension the width, for example a dimension transverse to the direction of rotation of the ring.

In an advantageous embodiment, it can be provided that edge sections in which the holes of the ring are delimited by the edge each have a length that is at least one half of a largest clear dimension of a largest and/or uncut hole of the arrangement, in particular in the interior. The length of the edge sections can significantly determine the steel image because it defines an outer dimension of the outer individual beams. This allows Avoid small individual beams. In an advantageous embodiment, it can be provided alternatively or additionally that edge sections in which the holes of the ring are delimited by the edge differ in length from one another by a maximum of 50%, preferably a maximum of 30%. This results in the most uniform external appearance possible of the emerging jet.

In an advantageous embodiment, it can be provided alternatively or additionally that edge sections in which the holes of the ring are delimited by the edge deviate in length from a largest clear dimension of a largest and/or uncut hole of the arrangement, in particular in the interior, by a maximum of 50%, preferably a maximum of 30%. The largest clear dimension is generally chosen based on a balance between the most efficient possible beam stabilization and the least possible beam disturbance. In this way, a dimensioning of the holes made for the interior of the beam can be transferred to the ring and thus to the outer individual beams.

The invention will now be described in more detail using exemplary embodiments, but is not limited to these exemplary embodiments. Further exemplary embodiments arise by combining the features of individual or multiple claims with one another and/or with individual or multiple features of the exemplary embodiments.

Fig. 1

eine Seitenansicht eines erfindungsgemäßen Strahlreglers,

Fig. 2

den Strahlregler nach Figur 1 in einem Axialschnitt,

Fig. 3

den Strahlregler nach Figur 1 in einer dreidimensionalen Schrägansicht auf seine Auslaufstruktur,

Fig. 4

eine Auslaufstruktur eines Strahlreglers nach dem Stand der Technik,

Fig. 5

eine Auslaufstruktur eines erfindungsgemäßen Strahlreglers,

Fig. 6

eine Auslaufstruktur eines zweiten erfindungsgemäßen Strahlreglers und

Fig. 7

eine Auslaufstruktur des dritten erfindungsgemäßen Strahlreglers.

It shows:

Fig.1

a side view of a jet regulator according to the invention,

Fig.2

the jet regulator Figure 1 in an axial section,

Fig.3

the jet regulator Figure 1 in one three-dimensional oblique view of its outlet structure,

Fig.4

a discharge structure of a jet regulator according to the state of the art,

Fig.5

an outlet structure of a jet regulator according to the invention,

Fig.6

an outlet structure of a second jet regulator according to the invention and

Fig.7

an outlet structure of the third jet regulator according to the invention.

The Figures 1 to 3 show a jet regulator according to the invention, designated as a whole by 1. The jet regulator 1 has an inflow side 2 and an outflow side 3. On the inflow side 2, an attachment sieve 4 is arranged, through which water flows into an interior space 32 of a housing 5. Functional units 6, for example a flow regulator 7 and/or a jet splitter 8 and/or a sieve insert 9, can be arranged in the housing 5.

The jet regulator 1 may have side ventilation openings to produce an aerated water jet or may be non-ventilated.

An outlet structure 10 is formed on the housing 5 on the downstream side 3.

Figure 4 shows a run-out structure 10 according to the prior art.

The outlet structure 10 has an outlet grid 11 through which a regular arrangement 12 of holes 13 of the same size and shape is created. These holes 13 can be referred to as uncut holes. Some holes are filled in so that the regular arrangement 12 is interrupted at these points 14.

The jet regulator 1 has a round outer contour 15 on the downstream side, which forms an edge 16 that delimits the outlet grille 11.

This edge 16 interrupts the regular arrangement 12, and the holes 17 adjacent to the edge 16 form a circumferential ring 18. The ring 18 is thus designed to deviate from the regular arrangement 12 in that the edge 16 cuts off individual holes 17 of the ring 18.

Due to the limitation of the regular arrangement 12, the holes 17 have different opening cross-sections, which vary from a full opening cross-section of a hole 13 to a fraction of this opening cross-section. These only partially formed holes 17 result in a deviation from the regular arrangement 12.

The holes 17 of the ring 18 define the external appearance of the emerging water jet.

In this case, a partial jet passes through each of the holes 13, 17, whereby the outlet grid 11 is dimensioned so thin that these partial jets recombine behind the outlet structure 10.

Figure 5 shows an outlet structure 10 of a jet regulator 1 according to the invention. Functionally or constructively to the

Jet regulator 1 after Figure 4 Similar or identical components and functional units are designated with the same reference symbols and are not described separately again. The explanations for Figure 4 are therefore considered Figure 5 accordingly.

The hole 19 in the ring 18 is enlarged at the expense of the hole 20 in the interior 22 in order to avoid its clear opening cross-section 21 being less than half as large as a clear opening cross-section, for example of the adjacent hole 17 in the ring 18, if the hole 20 had the full hexagonal shape of the - here exemplary hexagonal - regular arrangement 12. In the illustration, the regular continuation of the regular arrangement 12 is indicated by dashed hexagons 24.

Overall, this results in a ring 18 in which all holes 17, 19 are dimensioned such that no clear opening cross-section is smaller than half the clear cross-sections of the complete holes 13 of the regular arrangement 12.

In this case, it is actually harmless that individual holes 20 in the interior 22 within the ring 18 are very small. It has been found that these small holes 20 do not disturb the jet pattern, since the associated partial jets remain enclosed in the water jet.

It can be seen that the hole 19, if it were delimited by the hexagon 24, would deviate by more than 20% from the clear opening cross-section of an adjacent hole 23.

In Figure 5 It is further apparent that individual holes 25 are enlarged compared to the holes 13 in the interior 22 in order to To avoid the formation of tiny holes. In the outlet structure 10, the holes 17, 19, 25 that form the ring 18 are limited at the top so that the clear opening cross sections are not more than 1.5 times the clear opening cross sections of the holes 13 in the interior 22.

Overall, the distribution of the clear opening cross-sections over the outlet structure 10 is as homogeneous as possible with deviations of less than 15% from a median or mean value or a largest hole 26 in the interior 22.

By enlarging the holes 19, very small holes 27 are formed in the interior 22, the clear opening cross-section of which is less than 50% of another hole 28 in the interior 22.

The outlet structure 10 in Figure 5 has a sixfold rotational symmetry around the center, a point symmetry with respect to point reflections at the center, and three mirror symmetries on lines through the center.

Figure 6 shows an outlet structure 10 of another jet regulator according to the invention. Components and functional units that are functionally and/or structurally similar or identical to the preceding embodiments are designated with the same reference numerals and are not described separately again. The statements on the preceding figures therefore apply to Figure 6 accordingly.

Deviating from Figure 5 Here, 22 largest holes 26 are formed inside by combining very small holes with full holes 13.

Furthermore, the holes 19 in the ring 18 are significantly enlarged, but are still below the clear opening cross-section the largest holes 26.

Figure 7 shows an outlet structure 10 of another jet regulator according to the invention. Components and functional units that are functionally and/or structurally similar or identical to the preceding embodiments are designated with the same reference numerals and are not described separately again. The statements on the preceding figures therefore apply to Figure 7 accordingly.

Figure 7 represents a combination of the examples according to the Figures 5 and 6 represents.

Here too, the clear opening cross-section of the holes 19 does not exceed 1.5 times the opening cross-section of the largest holes 26 in the interior.

Although the clear opening cross-section of hole 23 is also reduced, this reduction is still acceptable for the formation of pleasing partial beams.

The outlet structure 10 has at least one hole 20 in the interior 22, which is adjacent to the ring 18 and whose clear opening cross section is less than 50% of another hole 28 in the ring 18 and of a largest hole 26 in the interior 22.

In the Figures 5 to 7 It is also evident, particularly by comparison with the hexagons 24 shown, that the enlarged hole 19 takes on a shape of the regular arrangement 12 in at least one section 29. This even applies to all holes 17, 19, 25 in the ring 18, in particular with the sections 29 each facing the interior 22.

In general, it can be said that the holes 17, 19, 25 forming the ring 18 have different clearances Opening cross-sections 21.

In the figures it can also be seen that the hole 20, which is located in the interior 22 of the outlet structure 10 and is adjacent to a hole 19 of the ring 18, is trimmed by this hole 19 of the ring 18 in such a way that its clear opening cross-section is smaller than that of the untrimmed holes 13 of the regular arrangement 12.

It can further be seen that no hole 19 of the ring 18 has a clear opening cross-section 21 which is smaller than one half of a clear opening cross-section of the uncut holes 13 of the regular arrangement 12.

Furthermore, it can be seen that a width 30 of the ring 18, i.e. a dimension transverse to the direction of rotation of the ring 18, is limited by a largest clear dimension of a largest and (uncut) hole 13 of the regular arrangement 12 in the interior 22.

Finally, it can be seen that edge portions 31, in which the holes 17, 19, 25 of the ring 18 are delimited by the edge 16, each have a length which is at least one half of a largest clear dimension of an uncut hole 13 of the arrangement 12 in the interior 22.

These edge sections 31 deviate in their length from each other and from a largest clear dimension of an uncut hole 13 of the regular arrangement 12 in the interior 22 by a maximum of 50%, here even by a maximum of 30%.

In further embodiments, the holes 19 are enlarged at the expense of an adjacent hole in the ring.

In general, it can be said that a form and an arrangement enlarged or trimmed holes 19 maintain a rotational symmetry of the regular arrangement 12.

In an outlet structure 10 of a jet regulator 1 according to the invention, it is thus proposed to form holes 17, 19, 25 in the edge region of a regular arrangement 12 larger than the regular arrangement 12 in order to avoid the formation of small holes 17, 19, 25 in the edge region.

List of reference symbols

1

Aerator

2

Inflow side

3

Downstream side

4

Front screen

5

Housing

6

Functional unit

7

Flow regulator

8

Beam splitter

9

Sieve insert

10

Discharge structure

11

Outlet grid

12

regular arrangement

13

(uncut) hole

14

Position

15

Outer contour

16

edge

17

Hole

18

ring

19

Hole

20

Hole

21

clear opening cross-section

22

Interior

23

adjacent hole

24

hexagon

25

Hole

26

biggest hole

27

small hole

28

another hole

29

Section

30

Width of 18

31

Edge section

32

Interior

Claims (15)

1. Jet regulator (1), comprising an outlet structure (10) having an outlet grid (11) with a regular arrangement (12) of preferably untrimmed holes (13) and an edge (16) delimiting the outlet grid (11), wherein holes (17, 19, 25) of the outlet structure (10) adjacent to the edge (16) form a ring (18) and delimit a water jet flowing through the outlet structure (10) to the outside, wherein holes (17, 19, 25) of the ring (18) are formed in deviation from the regular arrangement (12) due to the limitation of the arrangement (12) by the edge (16), so that the holes (17) of the ring (18) have different opening cross-sections, characterized in that each hole (19) of the ring (18) is enlarged at the expense of at least one adjacent hole (20) in the interior (22) of the ring (18) in deviation from the regular arrangement (12), if its clear opening cross-section (21) would otherwise be less than half as large as a clear opening cross-section (21) of an adjacent hole (23) of the ring (18) if the regular arrangement (12) were continued, and wherein at least one hole (20), which lies in the interior (22) of the outlet structure (10) and is adjacent to a hole (17, 19, 25) of the ring (18), is trimmed by this hole (17, 19, 25) of the ring (18) in such a way that its clear opening cross-section (21) is smaller than that of the largest and/or untrimmed holes (13) of the regular arrangement (12) and/or in that the at least one hole (20) in the interior (22), at the expense of which the hole (17, 19, 25) in the ring (18) was enlarged, has an opening cross-section (21) that differs from zero and/or in that the hole (20) in the interior, at the expense of which the hole (17, 19, 25) in the ring (18) was enlarged, is combined with a further hole in the interior to form a larger hole.
2. Jet regulator (1) according to claim 1, characterized in that the regular arrangement (12) is formed by preferably untrimmed holes (13) of the same size and/or the same shape.
3. Jet regulator (1) according to one of the preceding claims, characterized in that the ring (18) is formed in deviation from the regular arrangement (12) in that the edge (16) trims individual holes (17, 19, 25) of the ring (18).
4. Jet regulator (1) according to one of the preceding claims, characterized in that the enlarged hole of the ring (18) is enlarged at the expense of at least one adjacent hole (17, 19, 25), in particular of the ring (18).
5. Jet regulator (1) according to one of the preceding claims, characterized in that a hole (17, 19, 25) of the ring (18) is enlarged in deviation from the regular arrangement (12) if its clear opening cross-section (21) otherwise deviates from the clear opening cross-section (21) of the adjacent hole (23) by more than 20%, in particular more than 15%, if the regular arrangement (12) is continued.
6. Jet regulator (1) according to one of the preceding claims, characterized in that the holes (17, 19, 25) of the ring (18) have clear opening cross-sections (21) which are at most 50%, in particular at most 20% or 15%, above the clear opening cross-section (21), in particular on or below the clear opening cross-section (21), of a hole (13, 20, 26), in particular a largest hole (26) and/or an untrimmed hole (13), in the interior (22) of the outlet structure (10).
7. Jet regulator (1) according to one of the preceding claims, characterized in that the clear opening cross-sections (21) of the holes (17, 19, 25) of the ring (18) vary by at most 15%.
8. Jet regulator (1) according to one of the preceding claims, characterized in that the outlet structure (10) has at least one rotational, mirror and/or point symmetry.
9. Jet regulator (1) according to one of the preceding claims, characterized in that the outlet structure (10) has a hexagonal arrangement and/or in that the edge (16) is of circular design.
10. Jet regulator (1) according to one of the preceding claims, characterized in that the outlet structure (10) has in the interior (22) at least one hole (20), in particular adjacent to the ring (18), whose clear opening cross-section (21) is less than 50% of a further hole (28) in the ring (18) and/or in the interior (22), in particular a largest and/or untrimmed hole (13, 26).
11. Jet regulator (1) according to one of the preceding claims, characterized in that the enlarged hole (19) accommodates in at least one section (29) a shape of the regular arrangement (12).
12. Jet regulator (1) according to one of the preceding claims, characterized in that no hole (17, 19, 25) of the ring (18) has a clear opening cross-section (21) which is smaller than one half of a clear opening cross-section (21) of the largest and/or untrimmed holes (13, 26) of the regular arrangement (12).
13. Jet regulator (1) according to one of the preceding claims, characterized in that a shape and/or an arrangement of enlarged or trimmed holes (17, 19, 25) maintains a rotational symmetry of the regular arrangement (12).
14. Jet regulator (1) according to one of the preceding claims, characterized in that a width (30) of the ring (18) is limited by a largest clear dimension of a largest and/or untrimmed hole (13, 26) of the regular arrangement (12), in particular in the interior (22).
15. Jet regulator (1) according to one of the preceding claims, characterized in that edge sections (31), in which the holes (17, 19, 25) of the ring (18) are limited by the edge (16), each have a length which is at least one half of a largest clear dimension of a largest and/or untrimmed hole (13) of the regular arrangement (12), in particular in the interior (22), and/or deviate in their length from one another and/or from a largest clear dimension of a largest and/or untrimmed hole (13, 26) of the regular arrangement (12), in particular in the interior (22), by at most 50%, preferably at most 30%.

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