DE102015016124A1 - Method and device for producing prefilled containers filled with a liquid filling material by filling material introduced under pressure into the preform - Google Patents

Abstract

The invention relates to a method and an apparatus for producing containers filled with a liquid product from preforms by introduced under pressure into the preform product. It is an object of the invention to propose such a method and such a device in which both the desired filling pressure and the desired volume flow of the filling material is reliably available during the entire molding and filling phase. The object of the invention is achieved by a method in which the filling material is pressurized by a pressure pump 7 and is introduced at a forming and filling station 3 through a filling valve 6 in the preform 1, which is characterized in that one between the pump 7 and the filling valve 6 arranged pressure accumulator 10 is applied with closed filling valve 6 by the pump 7 with pressure and filled with a volume of filling material and the pressure accumulator 10 with the filling valve 6 is opened, the stored under pressure filling material to the preform 1. The object of the invention is also achieved by a corresponding device comprising a pressure pump 7 and a filling valve 6, which are interconnected by a supply line 2, which has a pressure accumulator 10, which in the supply line 2 between the pressure pump. 7 and the filling valve 6 is arranged.

Description

The present invention relates to a method and an apparatus for producing prefilled containers filled with a liquid filling product by means of filling material introduced under pressure into the preform.

Traditionally, containers, in particular bottles, are shaped in the blow-molding process by a molding gas flowing under pressure into a preheated preform, and in a second step are filled with a filling material, in particular a liquid filling material. For more rational production processes have recently been developed in which the preheated preform can not be formed and filled in one step by a compressed gas but by the supplied under pressure liquid product. Such a method is z. B. from the DE 10 2010 007 541 A1 known.

So that a preform can be formed into a container, it is thermally conditioned, that is, in particular heated and provided with a suitable temperature profile. In this case, the body of the preform z. B. heated to about 120 ° C and malleable, while the mouth area may only reach significantly lower temperatures, since the preform is held at the mouth area in the form and filling machine and must not deform under the usual holding forces there. For thermal conditioning, a device for producing filled containers has a heating section, along which the preforms are guided while being provided with the desired temperature profile.

The molding process must then proceed very rapidly so that the heat stored in the preform is sufficient to plastically deform the preform until completion of the molding process. Therefore, when molding with liquid product, the volume required for the molded container must be supplied to the preform under high pressure and within a short time interval. Typical filling times are in the range of 100 to 150 ms, whereby volume flows of up to 20 liters / s and more at pressures of up to 40 bar are required.

The beginning of the molding process is usually assisted by a stretch rod dipping into the preform, which mechanically applies pressure to the bottom of the preform to attract the preform and then take over the guidance of the soil so that the container can form symmetrically. For the transformation of the preform into a container, a minimum filling pressure required by the material and the shape of the preform and the container to be produced is required, wherein a higher pressure may be advantageous at the beginning of the forming phase in order to start the forming process.

In industrial processes, the molding and filling stations of a machine for producing filled containers are supplied with preforms in clocked form and successively shaped and filled. In this case, high volume flows are required during the filling time while no filling material flows in the cycle times between two fillings.

The required high volume flows are difficult to achieve with continuously running pumps, especially since the full power is needed only very briefly. Therefore, piston pumps are used for the hydraulic shaping and filling of containers whose stroke volume corresponds to the required quantity of filling material. The piston is driven by a linear motor, hydraulically or pneumatically, and the filling material located in the cylinder of the piston pump is pressed into the preform or into the forming container.

The reaction time of a piston pump is long compared to the filling time, so that in particular at the beginning of a molding and filling process, the desired volume flow is not achieved and a reproducible good distribution of the material of the preform can not be guaranteed in the molded container.

In addition, depending on the design of the filling device, several containers can also be filled in overlapping manner at several filling stations. With a piston pump of the type described above, a sufficient Füllgutzufuhr can not be guaranteed. The beginning and the end of successive fillings do not run smoothly and harmoniously, so that pressure pulsations may occur in the manifold system.

It is an object of the invention to propose a method and an apparatus for producing prefilled containers filled with a liquid filling material by means of filling material introduced under pressure into the preform, in which both the desired filling pressure and the desired volumetric flow of the filling material are maintained during the entire molding process. and filling phase is reliably available.

The object of the invention is achieved by a method for producing filled with a liquid product containers from preforms by under pressure into the preform introduced contents, wherein the contents are pressurized by a pressure pump and at a forming and filling station by a filling valve in the Preform is initiated.

The method according to the invention is characterized in that a pressure accumulator arranged between the pump and the filling valve is pressurized by the pump when the filling valve is closed and filled with a volume of filling material and the pressure accumulator discharges the product stored under pressure to the preform when the filling valve is open.

The inventive method has the advantage that a continuously running pump can be used. Although such pumps can reach the required high pressures, but usually not required for the filling large volume flow. In the cycle times between two filling operations, the pump pressurizes the pressure accumulator with filling material under pressure according to the invention when the filling valve is closed, whereby the pressure accumulator fills with a volume of filling material.

In a molding and filling process, a certain minimum pressure is required to deform the preform. Higher pressures can be used and are particularly advantageous in the initial phase of forming to initiate the forming process. The beginning of the forming process can also be supported by a stretch rod.

A certain maximum pressure should also not be exceeded, on the one hand because the system components are not designed and on the other hand, because the transformation of the preform into the container is not controlled.

The pressure accumulator used should therefore advantageously have a preload pressure that corresponds to the minimum mold pressure. The pressure of the accumulator increases when filled with the contents. Depending on the design and volume of the pressure accumulator, the pressure increase can be negligible or significant. For example, a preload pressure of 36 bar can be used, which increases to 40 bar when filled with the desired volume. If the pressure reached in the store is higher than the maximum filling pressure, pressure reducers must be provided in front of the forming and filling station.

The pump must be able to apply the pressure that should be reached in the pressure accumulator. Advantageously, the pump reaches a pressure corresponding to the maximum filling pressure. If the pump pressure is higher, appropriate means for pressure reduction are again provided.

The design described above as an example has the advantage that the pressure built up in the pressure accumulator during the forming and filling process is initially high, whereby the deformation of the preform can be more easily set in motion. Supportive and leading the beginning of the transformation can be facilitated, for example, by a stretch rod.

Subsequently, a lower pressure is usually sufficient to drive a once set transformation. The falling in the course of the molding and filling pressure of the pressure accumulator is therefore harmless, provided that a certain minimum pressure is maintained.

The volume of the pressure accumulator should correspond at least to the volume of the container to be formed and filled, that is, substantially the volume of the mold in which the preform is formed into the container. Depending on the application, however, the volume of the pressure accumulator may also be higher, in particular if the method is implemented with a shaping and filling device, on which containers can be shaped and filled in a temporally overlapping manner at a plurality of forming and filling stations.

The object according to the invention is also achieved by a device for producing prefilled containers filled with a liquid filling material by means of a filling material introduced into a mold at a forming and filling station under pressure into the preform, which comprises a pressure pump and a filling valve, which are connected by a feed line connected to each other. The device according to the invention is characterized in that it comprises a pressure accumulator which is arranged in the supply line between the pressure pump and the filling valve.

The pressure accumulator is preferably a gas pressure accumulator, which is biased at a pressure corresponding to the minimum forming and filling pressure.

The pump is preferably a continuously running pump. Any other type of pump capable of achieving sufficient pressure is also suitable. The working pressure of the pump should correspond at least to the minimum filling pressure, but advantageously to the maximum filling pressure. At higher pressures, appropriate pressure limiters must be provided in the liquid path in front of the filling valve.

Outside of a molding and filling process with the filling valve closed, the pump pressurizes the pressure accumulator with filling material under pressure. As long as the pressure achieved by the pump is greater than the pressure prevailing in the pressure accumulator, the pump pumps fluid into the pressure accumulator. In the pressure accumulator, a volume is stored which corresponds at least to the volume required for a molding and filling operation, ie essentially the volume of the mold in which the preform is formed into the filled container.

If the maximum volume of the pressure accumulator has been reached or if the pressure in the pressure accumulator rises to the desired value, the pump runs empty or the filling material is discharged via a return line with pressure relief valve.

For the actual molding and filling process, the filling valve is opened. It is immediately the full form and filling pressure available that was previously built in pressure accumulator. The volumetric flow required for the forming and filling process can be made available from the accumulator independently of the pump capacity.

As a result of the invention, it is no longer necessary to use a pump for the device which can deliver a high volume flow. It is sufficient if the pump provides a sufficiently high pressure and the pump power is high enough to fill the accumulator between two filling operations. The pump capacity must only correspond to the quantity of product filled per unit time. The short-term high volume flows are provided by the pressure accumulator.

In one embodiment of the invention may be arranged in the feed advantageously a damping element. As a damping element, in particular a gas pressure accumulator is suitable. Such a gas pressure accumulator may be provided with a gas filling, which is completed by a membrane in the memory against the supply line. As a damping element, a prestressed piston in a cylinder can be used, which can be biased for example by spring force or gas pressure.

If, at the end of a forming and filling process, there is a sudden increase in pressure, the gas poster in the pressure accumulator is compressed or the spring is tensioned and the pressure wave forming in this way is damped.

The pressure accumulator should have a pressure for this, which corresponds to the maximum filling pressure or slightly above it. The pressure accumulator is not stretched at normal filling pressure in this way and retains its capacity for absorbing the pressure wave at the end of the molding and filling process.

It has proven to be advantageous if the pressure accumulator is oriented relative to the forming and filling station so that the pressure wave propagating in the Leitungssytem between the forming and filling station and the pressure accumulator rechtwinkling on the membrane, d. h., That the propagation direction of the pressure wave is perpendicular to the membrane. This is ensured in particular when the diaphragm of the pressure accumulator is perpendicular to the axis of the preform. Due to the special propagation of waves in thin lines and the reflection on the cable walls, this effect can also be achieved with ensprechend curved lines in a different orientation.

For effective damping of the propagating pressure wave and the protection of the widest possible areas of the device, it is advantageous to arrange the damping element near the forming and filling station. Thus, it can be ensured that the pressure wave can propagate only in a spatially very limited area of the device and is effectively damped. More remote components of the device are effectively protected.

Since the pressure surges displace only a very small volume, the damping element can be designed correspondingly small. It suffices if, for example, a gas pressure accumulator has a maximum liquid absorption capacity of less than 500 ml, in particular less than 300 ml and preferably less than 150 ml.

The pressure strokes, which can hardly be determined at their pressure, can thus be controlled with only one simple element. System parts are protected against pressure surges where safety valves can no longer work.

An embodiment of the invention will be explained in more detail with reference to the accompanying figure.

1 shows schematically the structure of an embodiment of a device according to the invention.

It goes without saying for the person skilled in the art that the exemplary embodiment illustrated here is merely intended to illustrate the principle of the invention and is only reproduced schematically and not to scale. In particular, the illustrated dimensions and proportions of the elements with each other only serve to illustrate. The actual dimensions and proportions can be freely determined by the expert on the basis of his expertise. Moreover, only the components necessary for understanding the invention are shown. Real devices may include other components.

The device shown has a forming and filling station 3 in which a preform 1 within a mold 4 is transformed into a filled container. The form and filling station is available for this purpose 3 over a forming and filling head 5 with a filling valve 6 connected to a supply line 2 connected, through the molding and filling station 3 Contents from a reservoir 9 can be supplied under pressure.

For shaping and filling a container, the forming and filling head 5 placed sealingly on the mouth of the preform and fed to the preform within the filling time of a maximum of 150 ms contents with a pressure of 36 to 40 bar. For a 1.5-liter bottle, this requires a volume flow of the contents of at least 10 l / s.

This is the device with a pump 7 equipped, which runs continuously and reaches a pressure of 40 bar. The feed line 2 is behind the pump with a check valve 8th Mistake.

Furthermore, the device has a prestressed with a gas pressure accumulator 10 on. The pressure accumulator is preloaded at 36 bar and can absorb a volume of 1.5 liters at a pressure of 40 bar. The running pump 7 sets the contents in the supply line 2 under a pressure of 40 bar, allowing the gas in the accumulator 10 is compressed and the accumulator absorbs 1.5 liters of the contents. When the pressure of 40 bar is reached, the pressure accumulator no longer absorbs any other contents. That of the pump 7 conveyed product is via the pressure relief valve 11 and the return line 12 back to the reservoir 9 guided.

Is the accumulator 10 completely filled, the filling valve can 6 be opened. That in the accumulator 10 Stored filling material flows under the initial pressure of 40 bar and with high volume flow through the forming and filling head 5 in the preform 1 which is under the action of the contents within the mold 4 is transformed into the container and filled at the same time. Until complete formation and filling of the container, the pressure drops in the accumulator 10 to 36 bar, which is sufficient for the container molding.

The accumulator 10 reacts quickly and without delay and unlike the pump 7 provide the volume flow required for the short fill time. The container can therefore be made of the thermally conditioned preform 1 be formed before the temperature of the preform falls so far that it is no longer malleable.

After closing the forming and filling valve 6 The molded container can be from the forming and filling head 5 be separated and further processed, in particular by closing, labeling, etc. The pump 7 continues to run continuously and fills the accumulator 10 for the next forming and filling process again.

The device according to the invention has the advantage that a simple pump 7 can be used with a conventional liter performance, since the short time required for the molding and filling high volume flow from the pressure accumulator 10 stored and can be submitted if necessary.

In an industrial plant, the liter capacity of the pump 7 be designed so that it corresponds to the amount of filling per unit time. The high volume flows required during the molding and filling phases are filled and emptied by the pressure accumulator 10 reached. The accumulator 10 The volume should be designed in such a way that it can currently hold the container volume when forming and filling a container. In the time overlapping shaping and filling is the volume of the memory memory 10 increase accordingly.

To the supply line 2 is optional a damping element 20 connected. It is a gas pressure accumulator in which a gas cushion 20a under pressure behind a membrane 20b is included. The gas pressure corresponds to the maximum forming and filling pressure of the device, for example 38 bar. Depending on the container to be formed, however, the molding and filling pressure used may be different. Typically, the pressure of the gas cushion in the pressure accumulator can be between 36 and 44 bar, preferably between 40 and 42 bar.

When the preform 1 100 to 150 ms is converted into a filled container by the introduction of the filling material, it comes due to the high volume flow of the filling material to a pressure shock when the container is fully formed and its wall into contact with the wall of the mold 4 device. There is a pressure spike that propagates as a pressure wave backwards in the system. The height of the pressure peak is difficult to calculate. The components of the system are usually designed only for the filling pressure plus a safety margin. Continuous pressure surges can damage the components.

The gas pressure accumulator 20 can dampen the pressure wave by the short-term absorption of a small volume of product. This is the gas pressure accumulator 20 close to the forming and filling head 5 arranged so that the propagation of the pressure wave is limited to a limited area of the system and the upstream components are effectively protected.

Although pressure is spreading on all sides in the piping system, the pressure wave that occurs is propagated as a wave. It is therefore advantageous that the pressure accumulator is arranged so that the propagation direction of the shaft approximately at right angles to Membrane stands, since the pressure wave can then be particularly effectively damped.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102010007541 A1 [0002]

Claims (14)

Process for the manufacture of prefilled containers filled with a liquid product ( 1 ) by being pressurized into the preform ( 1 ) introduced contents, wherein the contents by a pressure pump ( 7 ) and at a forming and filling station ( 3 ) through a filling valve ( 6 ) in the preform ( 1 ), characterized in that one between the pump ( 7 ) and the filling valve ( 6 ) arranged accumulator ( 10 ) with the filling valve closed ( 6 ) from the pump ( 7 ) is pressurized and filled with a volume of filling material and the accumulator ( 10 ) with the filling valve open ( 6 ) the product stored under pressure to the preform ( 1 ). Method according to claim 1, characterized in that a continuously running pump ( 7 ) is used. Method according to claim 1 or 2, characterized in that the working pressure of the pump ( 7 ) at least equal to the maximum filling pressure. Method according to one of claims 1 to 3, characterized in that the biasing pressure of the pressure accumulator ( 10 ) corresponds to the minimum forming and filling pressure. Method according to one of claims 1 to 4, characterized in that the filling material receiving volume of the pressure accumulator ( 10 ) at the working pressure of the pump ( 7 ) corresponds to at least the volume of a container to be formed. Apparatus for producing containers of preforms filled with a liquid product ( 1 ) by at a forming and filling station ( 3 ) under pressure into the preform ( 1 ) within a mold ( 4 ) introduced filling material, comprising a pressure pump ( 7 ) and a filling valve ( 6 ), which by a supply line ( 2 ), characterized in that the device is a pressure accumulator ( 10 ), which in the supply line ( 2 ) between the pressure pump ( 7 ) and the filling valve ( 6 ) is arranged. Device according to claim 6, characterized in that the pump ( 7 ) is a continuously running pump. Apparatus according to claim 6 or 7, characterized in that the working pressure of the pump ( 7 ) at least equal to the maximum filling pressure. Device according to one of claims 6 to 8, characterized in that the biasing pressure of the pressure accumulator ( 10 ) corresponds to the minimum forming and filling pressure. Device according to one of claims 6 to 9, characterized in that the pressure accumulator ( 10 ) is a gas pressure accumulator. Device according to one of claims 6 to 10, characterized in that the receiving volume of the pressure accumulator ( 10 ) at the working pressure of the pump ( 7 ) at least the volume of the mold ( 4 ) corresponds. Device according to one of claims 6 to 11, characterized in that between the pressure pump ( 7 ) and the accumulator ( 10 ) a check valve ( 8th ) is arranged. Device according to one of claims 6 to 12, characterized in that in the supply line ( 2 ) a damping element ( 20 ), preferably a gas pressure accumulator, is arranged. Apparatus according to claim 13, characterized in that the damping element ( 20 ) has a maximum fluid intake of 500 ml, in particular of 300 ml, preferably of 150 ml.

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