APPARATUS FOR FORMING PLASTIC PREFORMS INTO PLASTIC CONTAINERS WITH STERILIZABLE ASEPTIC VALVE

Abstract

An apparatus for forming plastic preforms into plastic containers, has a plurality of forming stations each having application devices that apply the plastic preforms with a flowable and gaseous medium for their expansion. The apparatus has at least one first compressed air reservoir configured to store compressed air at a first predefined pressure. Each forming station has a valve arrangement with a plurality of valve devices configured to apply the plastic preforms with at least two pressures, wherein at least one of the valve devices is a pneumatically-controlled valve device. This valve device has a working chamber for receiving gaseous medium, used to act upon the plastic preforms, and a valve piston that can be moved between at least two positions. The valve device further has a control chamber that can be applied with a gaseous control medium for moving the valve piston.

Claims

1. An apparatus for forming plastic preforms into plastic containers, having a transport device that transports the plastic preforms along a predefined transport path, wherein the transport device has a transport carrier on which a plurality of forming stations for forming the plastic preforms are provided, wherein the forming stations in each case have application devices configured to apply the plastic preforms with a flowable medium for their expansion, and wherein the apparatus has at least one first compressed air reservoir that is configured to provide compressed air at a first predefined pressure, and each forming station has a valve arrangement with a plurality of valve devices configured to apply the plastic preforms with at least two pressures, wherein at least one of the valve devices is a pneumatically-controlled valve device, wherein the valve device has a working chamber configured for receiving the gaseous medium, used to act upon the plastic preforms, and a valve piston configured to be movable between at least two positions, and the valve device further has a control chamber configured to be applied with a gaseous control medium for moving the valve piston, and wherein at least one transition region is arranged between the working chamber and the control chamber.

2. The apparatus according to claim 1, wherein the working chamber and/or the transition region can be sterilized.

3. The apparatus according to claim 1, wherein the control chamber is sealed off from the transition region by at least one first sealing device, and/or the transition region is sealed off from the working chamber with at least one second sealing device.

4. The apparatus according to claim 3, wherein the first sealing device, which seals off the control chamber from the transition region, is configured such that it never contacts an aseptic region of the working chamber.

5. The apparatus according to claim 1, wherein the transition region is configured to act as a compression spring for pretensioning the piston device.

6. The apparatus according to claim 1, wherein the valve arrangement and/or the valve device has at least one sensor device.

7. The apparatus according to claim 1, wherein the valve device is designed without a bellows.

8. The apparatus according to claim 1, wherein the apparatus has a clean room within which the plastic preforms to be formed are transported.

9. The apparatus according to claim 1, wherein a control pressure for actuating the valve device is lower than a pressure of the gaseous medium for expanding the plastic preforms.

10. The apparatus according to claim 1, wherein the apparatus has a second compressed air reservoir that is configured to provide compressed air at a second predefined pressure, wherein such second pressure is higher than the first pressure.

11. The apparatus according to claim 1, wherein the apparatus is configured to be operated both in a working mode, in which the plastic preforms are formed, and in a sterilization mode, in which the apparatus and/or the valve device is sterilized.

12. A method for forming plastic preforms into plastic containers, wherein a transport device transports the plastic preforms along a predefined transport path, wherein the transport device has a transport carrier on which a plurality of forming stations for forming the plastic preforms are arranged, wherein the forming stations in each case have application devices that apply the plastic preforms with a flowable medium for their expansion, and wherein the apparatus has at least one first compressed air reservoir that provides compressed air at a first predefined pressure, and each forming station has a valve arrangement with a plurality of valve devices in order to apply the plastic preforms with the at least two pressures, wherein at least one of the valve devices is pneumatically controlled, wherein the valve device has a working chamber that receives the gaseous medium, used to act upon the plastic preforms, and a valve piston that can be moved between at least two positions, and the valve device further has a control chamber that can be applied with a gaseous control medium for moving the valve piston, and wherein a transition region is arranged between the working chamber and the control chamber.

13. A method for operating a forming device for forming plastic preforms into plastic containers, comprising providing a pneumatically controlled valve device, wherein the valve device has a working chamber for receiving the gaseous medium, used to act upon the plastic preforms, and a valve piston that can be moved between at least two positions, and the valve device further has a control chamber that can be applied with a gaseous control medium for moving the valve piston, and wherein a transition region is arranged between the working chamber and the control chamber; and controlling operation of the forming device using said valve device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0082] In the drawings:

[0083] FIG. 1 shows a schematic representation of an apparatus according to the invention;

[0084] FIG. 2 shows a schematic representation of a valve device in a closed state; and

[0085] FIG. 3 shows a representation of the valve device in an open state.

DETAILED DESCRIPTION OF THE INVENTION

[0086] FIG. 1 shows an apparatus 1 for forming plastic preforms 10 into plastic containers 15. This apparatus has a transport device 2 for transporting the plastic preforms with a rotatable carrier 22, on which a plurality of forming stations 20 are arranged. These individual forming stations each have blow-molding devices 82, which in their interior form a cavity for expanding the plastic preforms.

[0087] The reference sign 84 denotes an application device, which is used to expand the plastic preforms 10. This can be a blow nozzle, for example, which can be applied to a mouth of the plastic preforms 10 in order to expand them. In addition, it is also conceivable to seal the blowing nozzle on the blow-molding device. Preferably, this application device is movable in a longitudinal direction, and preferably exclusively in a longitudinal direction of the plastic preforms.

[0088] The reference sign 4 denotes a valve arrangement, such as a valve block, which preferably has a plurality of valve devices that control the application of different pressure levels to the plastic preforms. Each forming station preferably has such a valve block.

[0089] Preferably, a throttle device is also arranged on each of these valve arrangements, which controls the flow cross-section of the compressed air fed to the plastic preforms under at least one pressure. As mentioned above, at least some of such valve devices and preferably all of such valve devices can be sterilized.

[0090] In a preferred method, first, a pre-blowing pressure P1, then, at least one intermediate blowing pressure Pi that is higher than the pre-blowing pressure, and, finally, a final blow-molding pressure P2 that is higher than the intermediate blowing pressure Pi1 are applied to the plastic preforms. Particularly preferably, the plastic preforms are applied with a further intermediate blowing pressure Pi2 which is greater than the pressure Pi1, but smaller than the pressure P2.

[0091] After expansion of the plastic containers, the pressures or compressed air are preferably returned from the container to the individual pressure reservoirs.

[0092] The apparatus therefore preferably has an air recycling device that is suitable and intended to return compressed air from the individual forming stations to compressed air reservoirs, and in particular compressed air reservoirs that accommodate a lower pressure level.

[0093] The reference sign 88 denotes a stretching rod used to expand the plastic preforms in their longitudinal direction. Preferably, all forming stations have such blow molds 82 and stretching rods 88. This stretching rod is preferably a component of a stretching device denoted by 30. The stretching rod is (preferably, also exclusively) movable in the longitudinal direction of the plastic preforms 10.

[0094] Preferably, the number of such forming stations 4 is between 2 and 100, preferably between 4 and 60, and preferably between 6 and 40.

[0095] The plastic preforms 10 are fed to the apparatus via a first transport device 62, such as in particular, but not exclusively, a transport starwheel. The plastic containers 15 are transported away via a second transport device 64.

[0096] The reference sign 7 denotes a pressure supply device, such as a compressor or also a compressed-air connection. The compressed air is conveyed via a connecting line 72 to a rotary distributor 74 and from there passed on via a further line 76 to the first compressed air reservoir 32, which in this case is an annular channel.

[0097] Thus, preferably, such rotary distributor serves the purpose of feeding air from a stationary part of the apparatus into a rotating part of the apparatus.

[0098] In addition to such annular channel 32 shown, further annular channels are preferably provided, which are, however, concealed byfor example, lie underneath-the annular channel 32 in the illustration shown in FIG. 1. Accordingly, one pressure reservoir each is available for storing the pressure P2, as well as the intermediate blowing pressures Pi1 and Pi2 and the pressure P1.

[0099] The reference sign 33 denotes a connecting line that delivers the compressed air to a forming station 20 or the valve block 4 thereof. Preferably, each of the annular channels is connected to all forming stations via corresponding connecting lines. Such connecting line 33 is preferably arranged in the rotating part of the apparatus.

[0100] The reference sign 18 schematically denotes an optional clean room, which is here preferably annular and surrounds the transport path of the plastic preforms 10. Preferably, a (geometric) axis of rotation with respect to which the transport carrier 22 is rotatable is arranged outside the clean room 18. Preferably, the clean room 18 is sealed from the non-sterile environment by a sealing device, which preferably has at least two water locks. Preferably, this clean room is ring-shaped or torus-shaped.

[0101] Furthermore, the apparatus preferably has a cover device (not shown in FIG. 1), which delimits the clean room 18 upwards. This cover device is preferably arranged on at least one of the stretching devices 30.

[0102] The apparatus has a plurality of measuring and/or sensor devices which serve to control the apparatus. The reference sign 14 denotes a pressure-measuring device which measures an air pressure within the compressed air reservoir 32. The other compressed air reservoirs also preferably have corresponding pressure-measuring devices.

[0103] The reference sign 16 denotes a further pressure-measuring device which measures an air pressure-in particular, a container interior pressure of the plastic preform to be expanded. Preferably, such a pressure-measuring device is assigned to each forming station.

[0104] Preferably, the valve devices themselves also in each case have at least one and preferably several sensor devices such as pressure-measuring devices. In addition, the valve devices can also have sensor devices for detecting the concentration of a sterilization medium.

[0105] Preferably, the apparatus has a sterilization device that is suitable and intended to act upon the individual valve devices with a flowable sterilization medium. Preferably, this sterilization takes place in a sterilization mode that is different from a working mode of the apparatus.

[0106] The reference sign 19 also schematically denotes a flow-measuring device which determines a flow of the blowing air from a compressed air reservoir to the valve block 4 of a forming station 20. Preferably, corresponding flow-measuring devices are each arranged between a compressed air reservoir and all forming stations.

[0107] Additional flow-measuring devices can also be assigned between the additional compressed air reservoirs and the respective forming stations.

[0108] Furthermore, position-detection devices are preferably also provided which can detect positions of the stretching rods of the individual forming stations.

[0109] The reference sign 24 denotes a control device which controls and in particular regulates the apparatus 1. This control device is preferably also able to change the working parameters of the apparatus and in particular the settings of the throttle device.

[0110] The control device accordingly controls in particular the individual valve devices and hence the application to the plastic preforms of the individual pressure levels. In addition, the control device preferably also controls a movement of the stretching rods of the individual forming stations. Preferably, the control device also controls movements of the application devices, i.e., the blowing nozzles. As mentioned, this control device can preferably also adjust the settings of the individual throttle devices.

[0111] The control device is preferably suitable for controlling the points in time at which the application devices are applied to the plastic preforms and/or the points in time at which the blow-molding devices are again lifted from the plastic preforms, and in particular also for changing these points in time.

[0112] The reference sign 26 denotes a memory device in which in particular measured variables are detectedin particular, pressure values and flow values, but also corresponding working parameters. Preferably, these respective values are saved with a temporal assignment.

[0113] These values can preferably be saved continuously and in particular over long periods of machine operation. The control device controls or regulates the apparatus, also taking into account these recorded measured values.

[0114] The reference sign 28 roughly schematically denotes an inspection device for inspecting the manufactured containers.

[0115] The reference sign 25 denotes a display device which serves to output information to a machine operator. By means of this display devices, measured pressure (characteristic) curves can be output, for example.

[0116] FIGS. 2 and 3 show a valve device 50 according to the invention-once in a closed state (FIG. 2) and once in an open state (FIG. 3). The reference sign 56 refers to a working chamber that can be applied with the gaseous medium used to expand the plastic preforms. Preferably, this blowing pressure is permanently applied to this working chamber 56. The reference sign 57 denotes an outlet opening of the valve device, which is in flow connection with the application device, and thus with the plastic preform.

[0117] The reference sign 54 denotes a valve piston, which is shown in FIG. 2 in a closed position and in FIG. 3 in an open position of the valve device 50.

[0118] The reference sign 58 denotes a control chamber that can be applied with (non-sterile) control air in order to move the valve piston 54.

[0119] Due to the structure of the valve device, it can be divided into three zones, and specifically a first zone in which the working chamber 56 is located, a transition region or a second zone or transition zone, and a third zone in which the control chamber is located.

[0120] The reference sign 94 denotes a sealing device and in particular an O-ring, which seals the working chamber from the intermediate region 60. The reference sign 96 denotes a sealing device and preferably also an O-ring or the like, which seals off the control chamber 58 from the transition region 60.

[0121] A circumferential volume 60, which is preferably subjected to sterile air, is formed in the transition region. The reference signs 92 and 98 denote further sealing devices that additionally seal this transition region 60 both with respect to the control chamber 58.

[0122] The applicant reserves the right to claim all features disclosed in the application documents as essential to the invention, provided that they are novel with respect to the prior art individually or in combination. It is also pointed out that features which can be advantageous in themselves are also described in the individual figures. The person skilled in the art will immediately recognize that a particular feature described in a figure can be advantageous even without the adoption of further features from this figure. Furthermore, the person skilled in the art will recognize that advantages can also result from a combination of several features shown in individual or in different figures.