DE102014019400A1 - A method for producing containers filled with a liquid product from preforms made of a thermoplastic material and a device therefor - Google Patents

Abstract

The present invention relates to a method for producing containers (2) filled with a liquid filling material from preforms made of a thermoplastic material and to a device therefor. The object of the invention is to propose such a method as well as such a device in which it is possible to work predominantly with reduced pressure. To solve the problem, such a method is proposed, wherein the respective preform thermally conditioned and then during a forming phase in a mold by under pressure from a supply line (14) through a forming and filling head (3) in the preform introduced liquid product in the Container (2) is formed, characterized in that the preform is axially and radially stretched in a first phase by fed from the feed line (14) filling material until the preform has substantially reached the shape of the container (2), and the Füllgutzufuhr is separated in a second phase, so that downstream of the supply line (14) creates a closed volume, and the container (2) without further Füllgutzufuhr by pressure build-up in the closed volume (11) is fully formed.

Description

The present invention relates to a method for producing containers filled with a liquid product from preforms made of a thermoplastic material and to a device therefor.

Various methods for producing containers, in particular bottles, from preforms made of plastic are known from the prior art. For this purpose, the preform is at least thermally conditioned and then formed during a forming phase in a mold by introducing into the preform pressure medium under axial and radial stretching in the container. Besides blow-molding processes which use a gaseous pressure medium and fill the formed container in a separate step, methods have also been developed which use a liquid pressure medium. The molding and filling process can be done in this way in one operation. A blow molding process is z. B. from the DE 22 09 494 A known. A molding and filling process using the liquid medium as a pressure medium is z. B. from the DE 10 2011 011 076 A1 known.

For complete formation of a container high pressures of up to 40 bar are required, which represent a significant burden on the machines used and cause considerable costs because of the pressure-resistant components to be used. In addition, there is an increased risk of leaks at high pressure, which cause downtime of the machine in addition to the resulting contamination to remedy them.

The object of the invention is to propose a method and a device for the simultaneous shaping and filling of containers from preforms, in which it is possible to work predominantly with reduced pressure.

To solve the problem, a method for producing filled with a liquid product containers from preforms made of a thermoplastic material is proposed, wherein the respective preform thermally conditioned and then during a Umformphase in a mold by pressurized from a supply line through a forming and filling head in the preform introduced liquid product is transformed into the container. The method according to the invention is characterized in that the preform is axially and radially stretched in a first phase by filling material supplied from the feed line until the preform has substantially reached the shape of the container, and the filling material supply is separated in a second phase, so that downstream of the supply line, a closed volume is formed, and the container is completely formed without further Füllgutzufuhr by pressure build-up in the closed volume.

It has been found that for a coarse molding of a container from a preform, a lower pressure is completely sufficient, while a considerably higher pressure for the reliable formation of smaller details, such as special contours of the container, is required. Beverage bottles today usually have circumferential constrictions to increase the stability of the bottle or for better handling or as decorative elements, which sometimes have the finest imprints or edges. To form such details, a higher pressure is required.

According to the invention is in the preform during a first phase from a supply line, which may be suitably connected to a reservoir, filling material introduced through a forming and filling head, which is sealingly brought into contact with the mouth of the preform, filling material in the preform. The pressure of the product can be relatively low in this first phase. The container will be formed from the preform and will largely engage the mold and substantially reach the final shape of the container. However, the pressure is not sufficient to reliably form all the contours of the container. In this case, a stretching rod support in a generally known manner, the axial extension of the preform to the container.

To form all contours of the container, the supply line is separated in a second phase, expediently by a valve, and the Füllgutzufuhr thus interrupted. In the area downstream of the feed line thereby creates a closed volume, which is filled with filling material. Depending on the design of the forming and filling head, the volume may substantially correspond to the volume of the container or be larger. It is crucial that the supply line is separated from this closed volume and pressure from this volume can not propagate into the supply line. The largely, but not completely formed container is then completely formed without further Füllgutzufuhr by pressure build-up in the closed volume. The built-up pressure must be high enough to form the last not yet formed contours of the container.

Since the container can be formed in the first phase with relatively low pressure, the components of the supply line no particularly high demands are made. The components and their sealing connections are not heavily loaded. There is a low risk of leaks.

Since the container is already substantially formed in the first phase, in the second phase, although a higher pressure for shaping all the details, but no more Füllgutzufuhr longer required. To fill the finished container, the filling material present in the closed volume is sufficient.

In the first phase, the pressure can advantageously be up to 5 bar. The pressure to be established in the second phase can be up to 40 bar, the pressure being dependent on the shape of the container to be formed.

The pressure buildup can be done by displacement of contents, in particular by a piston or a membrane system or the stretch rod. The pressure built up can also be raised by a pressure booster with respect to the control pressure, so that z. B. a pneumatic or hydraulic control with lower pressure can be used.

The pressure build-up can also be done by local evaporation of the contents by z. B. an arc is ignited in the filling. In the area of the arc, the contents are locally vaporized, whereby an increase in volume by more than a factor of 1000 takes place and the pressure is increased correspondingly for a short time.

The closed volume can essentially correspond to the desired filling volume of the container. Due to the not yet complete formation of the container, the level in this case will initially be too high. Due to the shape achieved by the pressure of the container, the container increases its volume. If the pressure increase is achieved by Verdränguung, so z. Example, by a driving into the closed volume piston, the increase in volume of the container can correspond to the volume displaced by the piston. The container is completely formed after the pressure increase and completely filled. If necessary, the level can still be readjusted.

Since the shape of the container in the first step can take different amounts, the required displacement is not always precise predict. The final shaping of the container can be pressure-controlled, for which the displacement can be pressure-controlled.

The displacement can also be volume controlled, wherein the displaced volume must be chosen so large that it is sufficient in any case to form a not yet fully formed container. In this case, but also independently, it is advantageous to provide a pressure relief valve which opens at pressure above a predetermined value and allow contents to flow out of the closed volume, so that the maximum pressure is limited. A pressure relief valve can also advantageously limit the pressure, if a local evaporation of the medium or other means are used to Durckerhöhung.

In one embodiment of the invention, a check valve may be used to separate the feed line from the sealed volume. The first phase of the filling process can then take place at the lower filling pressure.

Subsequently, the pressure in the closed volume can be increased. The check valve closes at a pressure higher than the filling pressure, and the supply line is thus separated from the closed volume. The pressure can be increased to the desired level without the pressure propagating down to the delivery line.

To achieve the object according to the invention, there is further provided an apparatus for producing containers filled with a liquid product from preforms made of a thermoplastic material having a forming and filling station with a forming and filling head which can be sealingly brought into contact with the mouth of the preform, and a feed line for the contents, which is provided with a shut-off valve proposed. The device according to the invention is characterized in that the forming and filling head has a device for generating pressure with which a closed liquid volume present downstream of the shut-off valve can be put under pressure.

After the introduction of the contents under a first pressure through the supply line, the supply line can be separated from the forming and filling station by a shut-off valve. The first pressure must be selected only so high that the container is substantially formed. It is sufficient if it comes to a large area to the plant with the form, without all the details are formed.

After the closure of the shut-off valve downstream of the shut-off valve remains a closed Füllgutvolumen, essentially in approximately shaped container, but is decoupled from the feed line. With the device for generating pressure arranged on the forming and filling head, the contents are briefly pressurized in this closed volume, so that the container, including all contours, is formed. The pressure is higher than the pressure with which the product was previously supplied through the supply line.

The pressure generation can be done by displacement of contents within the closed volume. Devices for generating pressure can, for. As one or more pistons, a membrane system or a usually already existing stretch rod. To generate high pressures, a pressure booster can be provided. Preferably, the pressure generating device is pneumatically controlled. Hydraulic or electrical controls are also possible. The pressure generation can be pressure-controlled or volume-controlled.

Alternatively, the pressure generating device may be two high voltage electrodes for generating an arc. If the arc is ignited in the medium, the contents evaporate locally there. The volume increase in the evaporation is more than a factor of 1000, so that the pressure increases accordingly and the container is finally formed.

According to one embodiment of the invention, the device is equipped with a check valve as a shut-off valve. As soon as a pressure increase takes place in the closed liquid volume, the check valve closes and thus separates the feed line from the closed volume. The high pressure for final formation of the container is not transferred upstream into the supply line.

According to a further embodiment of the invention, the closed volume of liquid is connected via a pressure relief valve to the atmosphere. The pressure generation can then be arbitrary and does not have to be pressure-controlled. If the pressure rises too far, the pressure relief valve opens and allows contents to escape from the closed volume. Preferably, the leaking filling material is collected and returned to the product cycle.

Exemplary embodiments of the invention will be explained in more detail below with reference to the accompanying drawings, which show the following:

1 shows schematically a first embodiment of a forming and filling station of a device according to the invention for producing containers filled with a liquid filling material;

2 shows schematically a second embodiment of a forming and filling station of a device according to the invention;

3 shows schematically a further embodiment of a forming and filling station of a device according to the invention;

4 shows schematically a further embodiment of a forming and filling station of a device according to the invention;

5 shows schematically a further embodiment of a forming and filling station of a device according to the invention;

6 shows schematically a further embodiment of a forming and filling station of a device according to the invention;

7 shows schematically a further embodiment of a forming and filling station of a device according to the invention;

8th schematically shows a further embodiment of a forming and filling station of a device according to the invention.

In 1 schematically is an embodiment of a forming and filling station 1 a device according to the invention for producing containers filled with a liquid filling material 2 shown.

The form and filling station 1 includes a forming and filling head 3 that with a seal 4 is provided so that it seals with the mouth 5 a preform or a container forming therefrom 2 can be connected. The forming and filling head 3 is via a filling valve 6 and a feed line, not shown connected to a also not shown Füllgutspeicher. The product storage and the supply line are under a sufficient for a first molding of the preform pressure of up to 5 bar. The pressure depends, inter alia, on the shape of the container to be formed.

The forming and filling head 3 also has a stretch rod 7 which is to assist the axial stretching of the preform.

Next has the forming and filling head 3 via a device for generating pressure 8th , with the one in a pressure room 11 in the forming and filling head existing Füllgutvolumen can be pressurized. In the example shown is a piston assembly 9a . 9b as a pressure booster from a pneumatic supply 10 can be controlled.

After the first rough shaping of the container 2 by under a lower pressure from the reservoir supplied filling material is the filling valve 6 closed. Subsequently, the piston 9a the pressure generating device 8th through the pneumatic control 10 in the figure shifted to the left, so that the piston 9b in the pressure room 11 of the forming and filling head displaces a corresponding volume of liquid and in the form and filling head 3 as well as in the almost formed container 2 higher pressure is built up, so that the last contours of the container 2 molding.

By the prior separation of the supply line and the reservoir from the forming and filling head 3 by closing the filling valve 6 is only the pressure room 11 of the forming and filling head 3 as well as the container 2 under the higher pressure required to shape all contours 12 of the container 2 is required. The build-up of pressure does not involve the risk of leaks on the supply line or other upstream of the shut-off valve 6 plant components.

2 shows a similar structure as 1 , Unlike in 1 However, no separate piston assembly is provided for pressure build-up. Rather, the stretch rod is used 7 as a device for pressure generation 8th , The stretching rod 7 is shown here in her position after completion of the first process phase. During the first phase of the process, the stretch rod moves 7 down to the bottom of the mold, around the bottom of the preform when forming into the container 2 respectively. Then the stretch rod moves 7 back up. It is not necessary that the stretch rod 7 moves to the position shown in this figure. Each position sufficiently spaced from the bottom of the mold is sufficient. After closing the valve 6 drives the stretch rod 7 for the displacement of filling again briefly down, with a sufficiently high pressure is built up to the container 2 completely form.

3 shows a construction with a hollow stretch rod 7 , which is shown here in her position at the end of the first process phase. The preform was made with the support of the stretch rod 7 axially stretched and by introduction of contents approximately in the container 2 reshaped. For shaping the contours 12 is a device for generating pressure 8th provided here from one in the hollow stretch rod 7 arranged piston 9 consists. The piston 9 is inside the stretch rod 7 axially movable, so through the openings 13 the stretch rod 7 through the piston 9 displaced filling material emerge and the pressure in the pressure chamber 11 can increase, so that the contours 12 be formed.

4 shows a structure in which the forming and filling head 3 sealing with the mouth 5 the preform or forming container 2 connected is. The seal 4 leaves a vertical displacement of the forming and filling head 3 in the estuary 5 to. After completion of the first process phase, the valve becomes 6 closed, reducing the pressure chamber 11 forms a closed volume. By a movement of the forming and filling head 3 down into the container mouth 5 into this volume is reduced and pressure in approximately ausgefomten container 2 built so that the container is completely formed.

5 shows an embodiment with piston assembly 9a . 9b as in 1 , Deviating from 1 is a check valve as a shut-off valve 6 intended. Will the pressure in the pressure chamber 11 by operation of the piston 9b increases, so closes the check valve 6 and disconnects the feed line 14 from the pressure room 11 , The approximately shaped container 2 can be fully formed under high pressure, without the pressure in the supply line 14 would be pending. A check valve 6 as a shut-off valve can be combined with any conceivable device for generating pressure.

6 shows an embodiment in which in the pressure chamber 11 as a device for pressure generation 8th two electrodes 15 . 16 are arranged between which a high voltage source 17 located. Will a high voltage to the electrodes 15 . 16 created, this leads to evaporation 20 of the filling material in the area of the electrodes. The evaporation results in a volume multiplication of the contents, resulting in the pressure in the pressure chamber 11 rises sharply and allows the final shaping of the container.

7 shows a structure according to 1 in which the pressure chamber 1 via a pressure relief valve 18 features. The displacement by the piston assembly 9a . 9b can be volume controlled. As soon as the pressure exceeds a threshold, the pressure relief valve opens 18 and excess filling material can flow out through the valve and be returned to the product cycle.

In 8th is shown a structure in which the shut-off valve 6 immediately at the exit of the forming and filling head 3 is arranged. The forming and filling head 3 is as in the embodiment according to 4 vertically movable. The pressure room 11 is so that in the approximately shaped container 2 located volumes. After blocking the shut-off valve 6 can the forming and filling head 3 be moved down, causing filling in the pressure chamber 11 displaced and the pressure is increased. When molding the container 2 This once again slightly increases its volume. Through the into the container mouth 5 penetrating mold and filling head 3 arises after separation of the container 2 from the forming and filling head 3 at the same time the headspace of the container 2 ,

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 2209494 A [0002]
• DE 102011011076 A1 [0002]

Claims (15)

Method for producing containers filled with a liquid product ( 2 ) of preforms made of a thermoplastic material, wherein the respective preform thermally conditioned and then during a forming phase in a mold by pressure from a supply line ( 14 ) by a forming and filling head ( 3 ) introduced into the preform liquid contents in a container ( 2 ) is formed, characterized in that the preform in a first phase by from the supply line ( 14 ) is axially and radially stretched until the preform substantially the shape of the container ( 2 ) has been reached, and the Füllgutzufuhr is separated in a second phase, so that downstream of the feed line ( 14 ) a closed volume is formed, and the container without further Füllgutzufuhr by pressure build-up in the closed volume ( 11 ) is completely formed. A method according to claim 1, characterized in that the pressure during the first phase is lower than during the second phase. A method according to claim 1 or 2, characterized in that the pressure during the first phase is up to 5 bar and / or during the second phase up to 40 bar. Method according to one of claims 1 to 3, characterized in that the pressure build-up by displacement of filling material, in particular by one or more pistons ( 9b ), a membrane system or a stretching rod ( 7 ), he follows. Method according to one of claims 1 to 4, characterized in that the pressure using a pressure intensifier ( 9a . 9b ) is constructed. Method according to one of claims 1 to 5, characterized in that the pressure in the forming and filling head ( 3 ) is constructed pneumatically, hydraulically or electrically. Method according to one of claims 1 to 6, characterized in that the pressure build-up takes place by local evaporation of the filling material. Method according to one of claims 1 to 7, characterized in that the supply line ( 14 ) by a check valve ( 6 ) of the closed volume ( 11 ) is separated. Device for producing containers filled with a liquid product from preforms made of a thermoplastic material with a forming and filling station with a forming and filling head ( 3 ) sealingly in contact with the mouth ( 4 ) of the preform can be brought, and a feed line for the contents, with a shut-off valve ( 6 ), characterized in that the forming and filling head ( 3 ) a device ( 8th ) for generating pressure, with which a downstream of the shut-off valve ( 6 ) existing closed liquid volume ( 11 ) is pressurizable. Device according to claim 9, characterized in that the device ( 8th ) for generating pressure a displacer, in particular one or more pistons ( 9b ), a membrane system or a stretching rod ( 7 ). Apparatus according to claim 9 or 10, characterized in that the device for generating pressure a pressure booster ( 9a . 9b ). Device according to one of claims 9 to 11, characterized in that the device for generating pressure ( 9a . 9b . 10 ) is pneumatically, hydraulically or electrically driven. Device according to one of claims 9 to 12, characterized in that the device ( 8th ) for generating pressure two high voltage electrodes ( 15 . 16 ) are for generating an arc. Device according to one of claims 9 to 13, characterized in that the shut-off valve ( 6 ) is a check valve. Device according to one of claims 9 to 14, characterized in that the closed volume of liquid ( 11 ) via a pressure relief valve ( 18 ) is connected to the atmosphere.

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