DE102013100513A1 - Device for expanding plastic preforms into plastic containers, has blowing station with valve support, at which three valves are arranged, where two of three valves are arranged offset to each other with respect to longitudinal direction - Google Patents

Abstract

The device has a blowing station for expanding the plastic preforms by a gaseous medium. The plastic preforms is arranged at a movable carrier. An impinging unit impinges the plastic preforms to their expansion with the gaseous medium. A rod-shaped body is inserted in the interior of the plastic preforms to extend them in their longitudinal direction (L). The blowing station has a valve support (20), at which multiple valves (12 to 19) are arranged. Two of the multiple valves are arranged offset to each other with respect to the longitudinal direction.

Description

The present invention relates to a device for expanding plastic preforms to plastic containers. Such devices have been known for a long time from the prior art. In this case, heated plastic preforms are usually subjected to compressed air and formed against walls of blow molds to the containers. For this purpose, a loading device such as a blowing nozzle is placed on the mouths of the plastic preforms and applied to these with a gaseous medium and in particular with compressed air.

Recently, methods have also become known in which the plastic preforms are expanded with a plurality of pressure stages. It is also known that compressed air can be recycled again to allow for a higher overall energy savings. To do this, however, more and more valves are needed on a valve block. A higher number of valves on a valve block, however, means that these valves must be placed at a constant flow channel diameter farther away from a blow duct, which in turn has a larger dead space result.

The present invention is therefore based on the object to keep the resulting dead space as small as possible even with increasing numbers of valves. This object is achieved by a device for expanding plastic preforms according to claim 1.

Advantageous embodiments and further developments are the subject of the dependent claims.

A device according to the invention for expanding plastic preforms into plastic containers has at least one blowing station arranged on a movable carrier for expanding the plastic preforms by means of a gaseous medium. In this case, this blowing station on a loading device, which acts on the plastic preforms to expand them with a flowable, in particular gaseous, medium. Furthermore, the blowing station has a rod-shaped body, which is insertable into the interior of the plastic preforms in order to stretch them in their longitudinal direction, wherein the rod-shaped body is movable in this longitudinal direction relative to the plastic preforms. Furthermore, the blowing station has a valve carrier on which at least three valves are arranged in order to supply the gaseous medium to the loading device and / or to remove the gaseous medium from this loading device.

According to the invention, at least two of these three valves are arranged offset relative to one another at least in sections with respect to the longitudinal direction.

The longitudinal direction can also be defined by a standing perpendicular to the opening surface of the container standing line. The opening area is defined by the, normally circular, opening edge of the container, through which, the flowable medium is introduced.

In the prior art, said blow valves, which act on the container in particular with different pressures, usually the same height, in particular annular, or arranged in a line. The invention now proposes to arrange at least two of these valves in this longitudinal direction, which is usually also a height direction offset from each other. It is possible that the valves in their entirety offset from each other, for example, are arranged parallel to each other. However, this is not essential. Preferably, at least those regions of the valves which have the largest cross-section are arranged offset to one another in the longitudinal direction.

Advantageously, these valves themselves have control valves, for example electrical, magnetic or pneumatic control valves, and particularly preferably these control valves are arranged offset from one another in the longitudinal direction.

In a further advantageous embodiment, the movable support is a rotatable support on which preferably at least one and particularly preferably a plurality of blowing stations is arranged. In this case, these blowing stations preferably each have two folding-off side parts, which serve to receive a blow mold, which in turn forms the cavity within which the plastic preforms are expandable to the plastic containers. Advantageously, a pivot axis of these blow mold carriers or blow molds, which can be unfolded and folded, runs parallel to an axis of rotation of the carrier on which the blowing stations are arranged. The axis of rotation is in particular in a vertical direction, i. towards the center of the earth.

In a further advantageous embodiment, the device has at least two, in particular at least three pressure reservoirs, which serve for receiving the gaseous medium under different pressures. These reservoirs are in flow communication with the loading device via the valves mentioned above.

In a further advantageous embodiment, at least two of these valves are arranged offset to one another in a circumferential direction of the valve carrier which is defined with respect to the longitudinal direction. It is therefore proposed in this embodiment that the valves are arranged at least partially on the one hand annular with respect to the longitudinal direction, but in addition at least partially at different heights. In this way, it is possible overall to arrange the valves closer to one another and in this way in turn to provide more valves or, given a constant number of valves, to arrange them closer to a flow channel which leads to the loading device.

Thus, in a preferred embodiment, a shortest connection between two valves does not extend in a horizontal plane and not in a vertical plane, but in an oblique direction thereto. But it may also be that two of three valves are arranged at one level and another at a different height and the three valves form an equilateral triangle (seen from the longitudinal axis). Here is the shortest connection both in an oblique and in a horizontal plane.

In a further advantageous embodiment, the device has at least four preferably at least five valves. In this case, at least one valve is preferably used for supplying a gaseous medium into the plastic containers and at least one valve for removing the gaseous medium (in particular from the containers).

Thus, it is possible that, for example, at least four, preferably at least five valves are provided.

In a further advantageous embodiment, the valves each have a valve body which is movable in a straight direction, wherein at least two of these straight directions enclose an angle other than 0 ° with each other and preferably at least one direction also includes an angle different from 90 ° with the longitudinal direction. Advantageously, at least one of these directions extends obliquely to the above-mentioned longitudinal direction and in particular at an angle which lies with respect to the longitudinal direction between 10 ° and 80 °, preferably between 20 ° and 70 °, particularly preferably between 30 ° and 60 °.

The valve body may have an axis in its center, which has the same orientation as the straight directions. Here, two axes of two valve body can also cut. In particular, at least one, in particular at least two, axes can (at least) intersect with a longitudinal axis, which is arranged in the middle of the rod-shaped body.

The valves are in particular poppet valves, with a movable piston, which can seal a flow path on the front side (sealing surface). On the other end face of the piston is preferably a control surface, which can be acted upon by means of the pilot valves with flowable, pressurized medium for closing the valve.

In particular, the sealing surface planes of all valve bodies have a section line with at least one other sealing surface plane.

In particular, none of the sealing surface planes of the valve bodies are parallel to any other sealing surface plane.

It would also be possible for the said directions of movement of two valve bodies with respect to each other to be skewed in the mathematical sense. However, it is also possible that one of these directions is perpendicular to the stretch rod or the longitudinal direction and the other obliquely thereto.

In a further advantageous embodiment, several valves open into the same collecting space for the gaseous medium. It is possible, as mentioned above, that the said valves are in fluid communication with this collecting space via a connecting line. Again, an extension direction of this connection line of a valve may be inclined to a corresponding connection line of another valve.

It is possible that the first end portions of these connecting lines, which merge into the collecting space, at the same height with respect to the collecting space and the above-mentioned longitudinal direction. In this way, the collecting space can be kept smaller or shorter with respect to its extension in the longitudinal direction. Preferably, however, the second end portions of these connection lines, which are arranged on the valves, offset in the longitudinal direction to each other (or at least these second end portions of at least two connecting lines). In this way, while maintaining a relatively small collecting space, the valves occupying a large space can still be arranged offset from one another.

In a further advantageous embodiment, a distance between a surface of the valve carrier and the stretching rod or its longitudinal direction varies. This means that the valve carrier on its outer surface in particular is not cylindrical. Also, by such a configuration, it is possible to arrange a plurality of valves on the outer circumference.

In a further advantageous embodiment, at least two valves are arranged offset to one another both in the longitudinal direction and in a circumferential direction of the carrier defined with respect to the longitudinal direction. As mentioned, a geometric connection between these two valves may be oblique with respect to a horizontal or a vertical plane.

In a further advantageous embodiment, an outer surface of the valve carrier is formed axially symmetrical with respect to a geometric axis (but in particular with a shape deviating from a cylindrical shape). In this embodiment, the surface of the valve carrier is considered with the exception of the valves arranged thereon. Thus, it is possible that the valves are arranged, for example, along a spherical surface or generally the surface of an ellipsoid of revolution. The valves can also be arranged along a cylindrical surface, but offset in the longitudinal direction, or also on the surfaces of a (in particular uniform) solid whose surfaces lie in preferably equidistant distance to a solid center of gravity. By the procedure proposed here, the dead space can be minimized.

It is also possible for one or more valves or their pistons to be arranged inside the valve carrier. But it can also be arranged at least one sealing surface for a valve piston in the vicinity of the outer circumference of the valve carrier.

In a further advantageous embodiment, a plurality of valves are arranged in a zigzag shape in a circumferential direction of the valve carrier with respect to the longitudinal direction. This arrangement of the respective adjacent valves can also be achieved a space saving and the said valves can be arranged closer to each other.

In another advantageous embodiment, at least one valve is selected from a group of valves including pre-blow valves, inter-blow valves, final blow-off valves and bleed valves. Advantageously, the device has a Vorblasventil which controls a Vorblasvorgang for the containers, an intermediate blow valve which controls a Zwischenblasvorgang for the containers, a Fertigblasventil which controls a Fertigblasvorgang and a vent valve, which in particular after the expansion process air again from the container in the lets escape free atmosphere.

In a further advantageous embodiment, a second vent valve is provided, which particularly preferably performs a safety function if the abovementioned first vent valve fails.

In a further advantageous embodiment, a recycling valve is provided to guide blast air from the container into an additional store, which is in particular a ring channel, from which several blow stations pressure medium relate is. For this memory, the blowing air can be used for example for operating other pneumatic components or be discharged from the machine. There may also be a recycling valve which returns blowing air into a Vorblasluftdruckspeicher.

In a further advantageous embodiment, the device has a second recycling valve, if the above-mentioned functions should be cumulatively fulfilled. This further recycling valve can serve in particular as a safety valve for the first valve.

However, it would also be possible to provide two, three or even several recycling valves, in particular if the air is to be recycled from a further intermediate pressure stage between a pre-blowing pressure and a finished blowing pressure.

In particular, more than 2, preferably 3 and more preferably more than 4 compressed air reservoirs are arranged in the device, which serve for the supply and disposal of compressed air and which interact with the valves. In this case, a compressed air reservoir can also have only a small volume, such as a pipeline. With disposal on the one hand meant recycling within the machine, on the other hand, the recycled air but not only for a further blowing step (pre-blowing, intermediate bubbles) can be used, but also outside the machine for bottle bottom cooling or for an external compressed air network.

In a further advantageous embodiment, the carrier or valve carrier has a main blowing channel, into which the individual valves open. Advantageously, this main blower channel is at least partially annular. It can also be cylindrical.

Advantageously, the above-mentioned stretching rod penetrates the said main blowing channel. In particular, the stretching rod penetrates the main blower channel concentrically. This main blower channel here also represents the above-mentioned collection space.

In a further advantageous embodiment, the three valves are arranged in a ring around a stretching rod.

In a further advantageous embodiment, at least two, preferably at least three valves or the directions of movement of their pistons are arranged at an angle to the plane of movement of the containers, between 100 ° and 170 °, preferably between 115 ° and 155 °, particularly preferably between 120 ° and 150 °. Advantageously, the respective valve piston is thereby moved obliquely downward to reach a sealing position.

In a further advantageous embodiment, one or more valves are arranged with respect to the piston axes and the directions of movement at an angle to the plane of movement of the containers, between 10 ° and 80 °, preferably between 25 ° and 65 °, particularly preferably between 30 ° and 60 °. In this case, the valve pistons move to reach the closing position obliquely upward with respect to the plane of movement of the plastic containers.

In particular, a plane spanned by three centers of gravity of three adjacent valve pistons is a triangle, wherein in particular all internal angles of the triangle are smaller than 89 °. In particular, the triangle is a substantially equilateral triangle. Essentially this means 60 ° with the tolerance +/- 20 ° for an angle.

If six valves are provided, two such triangles may also be provided twice, each with three different valves.

In the case of four adjacent pistons, the surface is in particular a parallelogram, the acute angles being in particular smaller than 90 °, in particular smaller than 70 °, and the dull ones larger than 90 °, in particular greater than 110 °. In particular, the acute angles are substantially at 60 °.

The same applies in particular to 5 piston centers of gravity: this is in particular a trapezoid, with the acute angles lying substantially at 60 ° and the obtuse angles being substantially at 120 °.

In the variants with more than 3 valves, the curvature is calculated out in a circular distribution of the valves and the surface "rolled up" or straightened.

In particular, one side, in particular two sides, of the polygon is parallel to the transport plane of the container and / or perpendicular to the longitudinal direction of the rod-shaped body.

Advantageously, at least two different types of valves may be provided, wherein in the first type the valve pistons move obliquely upward with respect to the plane of movement of the containers and obliquely downward with the other type.

It would also be possible to move the valve pistons of one kind parallel to the container movement plane and those of the other type obliquely or perpendicularly thereto.

It would also be possible to move the valve pistons of one or two genera parallel to the container movement plane, wherein the valve piston of a genus circumferentially in or on the valve block at least half the diameter of a valve piston is arranged offset to the other genus. In particular, these two genera are in different levels.

It would also be possible that the support for the valves is not penetrated by the stretch rod in the center, but is arranged laterally at the blowing station.

Depending on the blowing process and preform could also be dispensed with a rod-shaped body (stretching rod).

In a further preferred embodiment, viewed radially outwards from a center of the valve carrier, a valve, or a surface spanned over its center of gravity, is essentially a triangle, wherein in particular all interior angles of the triangle are smaller than 120 ° are less than 90 °.

It is also possible for at least four, in particular five, valves to be arranged on the carrier with which two, in particular three, such triangles can be formed. A valve can also serve as a corner point in two different triangles.

Assigning at least five valves in three different levels, it follows, seen radially outward from the center of the valve block, for the five valves, an arrangement that corresponds to one of five game dice. Within the four resulting triangles (see above), an interior angle may also be 90 ° or greater.

The valve pistons are in particular made of a plastic, in particular of PET. In contrast, the valve block is preferably made of a Metal, in particular made of an aluminum alloy.

Further advantages and embodiments will become apparent from the accompanying drawings.

Show:

1 a schematic representation of a device according to the invention for forming plastic preforms to plastic containers;

2a . 2 B two illustrations of a prior art arrangement;

3 a first embodiment of a device according to the invention;

4 a representation for illustrating the distribution of valves;

5 another possible arrangement of a plurality of valves;

6 a representation of two valves in a side view;

7 another possible arrangement of a plurality of valves;

8th a further embodiment of the invention with an offset stretching rod;

9 another illustration with staggered stretch rod;

10 a representation with laterally offset stretch rod; and

11 a representation of in 10 shown device with consideration of internal elements.

1 shows a device according to the invention 1 for forming plastic preforms 10 to plastic containers. This device has a rotatable about a rotation axis D carrier 22 on. This axis of rotation is preferably perpendicular, that is, it is thus aligned in particular to the center of the earth. On this rotatable carrier 22 is a variety of blowing stations 2 arranged. These blow stations 2 each have openable and closable blow molds in which plastic preforms can be accommodated. Subsequently, these plastic preforms are expanded by applying compressed air. Furthermore, the individual blowing stations each have a carrier on which a plurality of valves is arranged, each of which serves to supply the individual pressure stages. The machine 1 especially rotates continuously and the stations 2 are in particular at equidistant intervals along the circumference of the carrier 22 arranged.

2a and 2 B show a representation of an arrangement of the prior art. Here is a carrier 120 provided on which a variety of valves 122 . 124 . 125 . 126 and 128 is arranged. These valves are arranged at the same height with respect to the longitudinal direction, which extends here perpendicular to the plane of the figure. One recognizes furthermore respective connecting lines 110 over which the valves are connected to a plenum 130 keep in touch. The reference number 4 features a stretch rod. These individual connecting lines 110 represent a dead space for the device, which is to be kept as low as possible. Will you in the state of the art now, as in 2 B To increase the number of valves you have to put them in the plenum at the same time 130 can lead, the respective connecting lines 110 lengthen so that the pistons have enough space around the circumference. However, this has an increase in the dead space (in particular by the extension of the connecting lines) result.

3 shows a schematic representation of a device according to the invention. Here again is a valve carrier 20 provided on which a variety of valves 12 . 14 . 15 . 16 . 17 . 18 . 19 is provided. Here are the valves 12 . 15 . 17 . 19 in the figure level, the other valves 14 . 16 and 18 However, they are not arranged in this plane, but are located outside the plane and are preferably on inclined connecting lines 34a with the collection room 30 in fluid communication. This is due to the staggered arrangement of these valves 14 . 16 . 18 possible to shorten the distance of the valves to the collecting space again and thus also the connecting lines 34 and 34a shorter.

The reference number 4 refers here again to a stretch rod, which through the collection space 30 passes through and extends (and also moves) in the direction L which is perpendicular to the plane of the figure. The reference number 24 indicates a support for the valve carrier. The reference numerals 12a . 14a . 15a . 16a . 17a . 18a . 19a refer to valve bodies that are each movable in predetermined rectilinear directions. The reference symbol R15 identifies one of these directions of movement as an example. Here are the four directions of movement of the valve body 12a . 15a . 17a and 19a here in the plane of the figure, the other directions of movement of the valve body 14a . 16a and 18a However, they are preferably oblique to this. It would be possible that these directions are inclined upwards in the aforementioned angle or obliquely downward.

The reference number 32 identifies each body of the valves, which, as in 3 shown, take a certain amount of space.

4 shows a representation for illustrating the arrangement of the individual valves or their valve body 32 , The individual valves can be designed so that in a settlement of the bore of the channel for the blow piston as much surface is provided with holes from the valves. This is the in 4 embodiment shown an example of a cylindrical arrangement of the valve carrier 20 ,

5 shows a further possible embodiment of the valve body. In this embodiment, the valve carrier is designed as a polyhedral structure, each having a plurality of obliquely arranged outer surfaces 30a . 30b having. The reference number 38 again denotes a channel through which the stretch rod can be passed. It is possible, for example, that the valves 16 . 17 and 18 are designed as pilot valves.

6 shows a simplified illustration of an inventive arrangement. To illustrate, here are only two valves 12 . 14 shown. About the channels 12b . 14b compressed air can be supplied here. In a closed position of the valves 12 . 14 in which the respective piston 12a . 14a is closer to the longitudinal axis L, the valves are closed. If the pistons 12a and 14a in their rearward position, that is, further away from the longitudinal axis L, the valves are open and the blast air can be in the plenum 30 lead. It can be seen that here the blast air from both channels 12c . 14c each flows into the same collecting space.

The reference number 6 indicates a loading device such as a blowing nozzle, which on a support ring 10a of the plastic preform 10 can be put on. For this purpose, this admission device 6 also a circumferential sealing device 62 like here an O-ring-like element on which the support ring 10a can be put on.

7 shows a further illustration of a device according to the invention. In this illustration, a total of six valves 12 . 14 . 15 . 16 . 17 . 18 shown here along a spherical carrier 20 are arranged. Also, this spherical support allows a smaller distance of the valves to each other and thus a reduced dead space. The reference number 48 indicates a sealing device which is used to seal the stretching rod movement 4 serves. If a higher number of valves is needed, these could still be outside the in 7 level shown, without obstructing the above valves in terms of their space. At the in 7 As shown embodiment, the valve carrier could also be disc-shaped with a circular surface or as a half-cylinder.

As part of the valve 16 For example, both a pilot valve and a blow valve may be provided, wherein the piston 16a is a movable piston, which serves to control the blowing process and the reference numeral 16d refers to a corresponding pilot valve, which in turn controls the movement of the piston 16a controls. Preferably, a plurality of the valves and preferably all of the valves shown corresponding pilot valves, which are not shown, however. This pilot valve could preferably in the body 32 be integrated.

8th shows a further illustration of a device according to the invention. In this illustration, some of the valves are also arranged at different heights in the longitudinal direction L here. In contrast to the embodiments shown above, however, here the stretching rod does not pass through the collecting space 30 but is arranged next to it and stands with the collecting space 30 over a connecting line 31 in fluid communication. The reference number 52 denotes a carrier for the stretch rod. In other words, here is the valve carrier 20 not arranged around the stretch rod, but laterally next to this stretch rod.

9 shows a further possible embodiment of such an arrangement, in which case the individual valves 12 . 14 . 15 . 16 . 18 are arranged such that the stretch rod 4 although laterally offset to the collection space 30 is, but the connection line 31 can be kept considerably shorter.

10 shows a perspective view of the in 9 shown device. Again, you recognized the stretch rod again 4 attached to the carrier 52 is arranged, or passes through it.

At the in 11 In the embodiment shown, the interior of the device is also visible. Here is a collection room 54 provided, which is completed up and down and in which the individual valves, or their pressure lines open. Furthermore, here is a channel 56 intended. This connecting channel between the collecting space 54 and one the stretch rod 4 surrounding channel 58 is advantageously carried out obliquely and more preferably obliquely downwards in the direction of the channel 58 or the tuyere adjacent to this channel (not shown). By this oblique configuration turbulence can be reduced or avoided.

The inventive arrangement, it is possible that more than 50% of a valve piston are within a valve block. Advantageously, the normals point to the sealing surfaces of at least one piston ( 12a . 14 . 15a . 16a . 17a . 18a and 19a ) in the direction of a blow duct or the collecting space 30 or an extension of this blower channel. Advantageously, the individual valve piston 12a . 14a . 15a . 16a . 17a . 18a . 19a each round in cross-section.

The Applicant reserves the right to claim all features disclosed in the application documents as essential to the invention, provided they are novel individually or in combination with respect to the prior art.

LIST OF REFERENCE NUMBERS

1

contraption

2

blowing stations

4

stretching rod

6

Loading device / nozzle

10

The plastic preforms

10a

support ring

12, 14-19

valves

12a, 14a-19a

Valve body / piston

12b, 14b

channels

12c, 14c

channels

16d

pilot valve

20

valve

22

rotatable carrier

24

Carrier for valve carrier

30

plenum

30a, 30b

exterior surfaces

31

connecting line

32

Basic body of the valves

34

interconnectors

34a

sloping connecting lines

38

channel

48

seal means

52

carrier

54

plenum

56

channel

58

channel

62

seal means

110

Connecting lines (prior art)

122, 124, 125, 126, 128

Valves (prior art)

130

Collecting space (prior art)

D

axis of rotation

L

longitudinal direction

R12, R14-R19

Direction of movement of the pistons

Claims (12)

Contraption ( 1 ) for expanding plastic preforms ( 10 ) to plastic containers with at least one on a movable support ( 22 ) arranged blowing station ( 2 ) for expanding the plastic preforms ( 10 ) by means of a gaseous medium, with at least one impingement device ( 6 ), which the plastic preforms ( 10 ) is acted upon by a gaseous medium, with a rod-shaped body ( 4 ), which penetrate into the interior of the plastic preforms ( 10 ) is insertable to stretch in the longitudinal direction (L), wherein the rod-shaped body ( 4 ) in this longitudinal direction (L) with respect to the plastic preforms ( 10 ) is movable, wherein the blowing station ( 2 ) a valve carrier ( 20 ), on which at least three valves ( 12 . 14 . 16 ) are arranged to the loading device ( 6 ) supply the gaseous medium and / or the gaseous medium from the loading device ( 6 ), characterized in that at least two of these three valves ( 12 . 14 . 16 ) with respect to the longitudinal direction (L) at least partially offset from one another. Contraption ( 1 ) according to claim 1, characterized in that at least two of these valves ( 12 . 14 . 16 ) in a circumferential direction of the carrier defined with respect to the longitudinal direction (L) ( 20 ) are offset from one another. Contraption ( 1 ) according to at least one of the preceding claims, characterized in that the device ( 1 ) at least 4, preferably at least 5 valves ( 12 . 14 . 16 . 17 . 18 ) having. Contraption ( 1 ) according to at least one of the preceding claims, characterized in that the valves ( 12 . 14 . 16 . 17 . 18 ) in each case in a straight direction (R1) movable valve body ( 12a . 14a . 16a . 17a . 18a ), wherein at least one of these directions includes an angle different from 90 ° with the longitudinal direction (L). Contraption ( 1 ) according to at least one of the preceding claims, characterized in that a plurality of valves ( 12 . 14 . 16 . 18 ) in the same collection room ( 30 ) for the gaseous medium. Contraption ( 1 ) according to at least one of the preceding claims, characterized in that between the valves ( 12 . 14 . 16 . 18 ) and the collection room ( 30 ) Connecting cables ( 34 . 34a ) are provided, via which the valves ( 12 . 14 . 16 . 18 ) with the collecting space ( 30 ) can be brought into flow connection, wherein at least one of these connecting lines ( 34a ) in one of 90 ° deviating angle with respect to the longitudinal direction (L) extends. Contraption ( 1 ) according to at least one of the preceding claims, characterized in that a distance between a surface of the valve carrier ( 20 ) and the stretch rod ( 4 ) varies in the longitudinal direction (L). Contraption ( 1 ) according to at least one of the preceding claims, characterized in that at least two valves in both the longitudinal direction (L) and in a relative to the longitudinal direction (L) defined circumferential direction of the carrier ( 20 ) are offset from one another. Contraption ( 1 ) according to at least one of the preceding claims, characterized in that an outer surface of the valve carrier ( 20 ) Is formed axially symmetrically with respect to a geometric axis (L). Contraption ( 1 ) according to at least one of the preceding claims, characterized in that a plurality of valves ( 12 . 14 . 16 . 18 ) in a circumferential direction of the valve carrier ( 20 ) with respect to the longitudinal direction (L) zig-zag - are arranged with respect to each other. Contraption ( 1 ) according to at least one of the preceding claims, characterized in that seen from a center of the valve carrier radially outwardly, one on the valve piston, or their centers of gravity, three valves ( 12 . 14 . 16 . 18 ) is substantially a triangle, wherein in particular all internal angles of the triangle are smaller than 120 °, preferably smaller than 90 °. Contraption ( 1 ) according to claim 11, characterized in that at least four, in particular five, valves ( 12 . 14 . 16 . 18 ) on the support ( 20 ) are arranged, with which two, in particular three, such triangles can be formed.

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