US20160053777A1

US20160053777A1 - Device and process for vacuum recycling in a container treatment unit

Info

Publication number: US20160053777A1
Application number: US14/826,521
Authority: US
Inventors: Frank Winzinger; Wolfgang Roidl
Original assignee: Krones AG
Current assignee: Krones AG
Priority date: 2014-08-20
Filing date: 2015-08-14
Publication date: 2016-02-25
Also published as: CN105383041A; EP2987604B1; EP2987604A1; CN105383041B

Abstract

A device for vacuum recycling in a container treatment unit with a plurality of treatment stations that each have a sealable vacuum area, including a plurality of connection lines, which connect the vacuum areas to each other and/or to a central vacuum accumulator, and a control and/or regulating unit that is configured such that a vacuum created in a vacuum area is partially transferred to another vacuum area and/or the central vacuum accumulator.

Description

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to European Application No. 14181649.6, filed Aug. 20, 2014. The priority application, EP 14181649.6 is hereby incorporated by reference.

FIELD OF THE DISCLOSURE

The disclosure relates to a device and process for vacuum recycling in a container treatment unit, particularly for use in forming and filling containers, such as bottles.

BACKGROUND

Filling device for the filling of containers and blowing and/or stretch blowing devices are well known in the field of bottling technology, in particular, beverage bottling. More recently, form-filling machines for simultaneous molding and filling of plastic containers have also been used.
As known, plastic containers can be produced out of preforms in a stretch blowing process.
In particular, the plastic containers prior to the expansion are preforms that preferably have the shape of a test tube and/or that have one single aperture. Close to this aperture there is an outlet area, which is equipped, for example, with a thread for a seal that has already been shaped during the injection molding process. In addition, a support ring for the purpose of transportation can be provided for in the outlet area.
As an alternative for inflating the containers with pressurized air, the EP 1529620 B1 describes a process for hydraulic reshaping of preforms into plastic bottles. For this purpose, the preforms are at first heated and brought into a hollow mold where they are stretched in a longitudinal direction. Further, mineral water or the like is added with overpressure in order to produce the final container shape. The mineral water remains in the container so that a subsequent separate bottling step can be omitted.
The US 2011/0031659 A1 further describes a process in which a heated preform is stretched by means of a stretching rod and then dilated hydraulically into a container by means of an incompressible fluid, in particular, water. Afterwards, the fluid is displaced by pressurized air and flows out of the container.
A form-filling machine comprises, according to the definition, at least one treatment station for expanding reshaping of plastic preforms into plastic containers in a hollow mold and for filling a substantially liquid product or at least a liquid or solid component of the product into the plastic containers.
Liquids, also those that contain dissolved carbon dioxide or the like, are, according to their definition and with regard to their function during molding and filling of the containers, incompressible fluids in contrast to gases that are functionally defined as compressible fluids.
Just as in a filling unit or a blowing and/or stretch blowing system, the molding and/or filling process can be accelerated by means of creating a partial vacuum in the process chamber, which is therefore designed as a pressure-tight vacuum chamber. After adding the preform or container to be added, the vacuum chamber, however, has to be evacuated up to the desired process pressure at first, which generally happens directly by means of a vacuum pump that is connected to the vacuum chamber through appropriate suction lines. When the vacuum chamber is opened again to take out the treated container, the created vacuum is though lost due to pressure equalization with the environment whereby a large part of the power applied by the vacuum pump remains unused.

SUMMARY OF THE DISCLOSURE

Hence, the present disclosure is based on the purpose of taking advantage of this unused part of the vacuum pump power as optimally as possible. Broadly spoken, one aspect of the present disclosure consists of improving the energy efficiency of the container treatment unit and of reducing the energy consumption of the vacuum pump. Through reduction of the vacuum pump, the unit should, in addition, be designed in a more compact way.
Thus, the disclosure relates to a device and a process for vacuum recycling in a container treatment machine in connection with filling systems to fill containers, for example bottles, with a substantially liquid filling product, e.g. a beverage or a hygiene product, blowing and stretch blowing devices to produce plastic containers such as PET bottles through impingement of appropriate preforms with a compressed gas and combined form-filling devices for simultaneous molding and filling of plastic containers through filling of the preforms under pressure with the filling product, in which a negative pressure is created in a vacuum chamber of the treatment station in order to accelerate the molding and/or filling process.
The abovementioned problems are solved by a vacuum recycling device in a container treatment unit, comprising a plurality of treatment stations that are each equipped with a sealable vacuum area, a plurality of connection lines that link the vacuum areas to each other and/or to a central vacuum accumulator, and a control and/or regulating unit configured in a way that a vacuum created in a vacuum area is partially passed on to another vacuum area and/or the vacuum accumulator.
Here and in the following part, the notion “vacuum” shall be understood in a way that the predominant pressure in the vacuum is lower than the pressure of the environment. In particular, the predominant pressure can be in the range of 0.1 to 0.9 bar, preferably of 0.3 to 0.8 bar, even more preferably of 0.5 to 0.7 bar. Depending on the treatment station, however, other pressure ranges are also possible for the vacuum. The present disclosure is explicitly not limited to the mentioned ranges but can in principle be applied to any vacuum pressure.
In particular, negative pressures of 0.1 to 0.4 bar can also be achieved in the vacuum area.
In particular, in the container to be filled there is a pressure of 0.05 to 0.9 bar, preferably between 0.1 and 0.8 bar, immediately prior to the filling process.
In particular, the pressure in the vacuum area deviates from the pressure in the container by less than 0.2 bar immediately prior to the filling process. However, there can also be an equal pressure.
Here and in the following, a vacuum area shall be understood as a sealable volume of a treatment station to perform a treatment process on one or several containers and/or preforms, whereby the volume to perform the treatment process is evacuated to a pressure that is lower than the pressure of the environment. Thereby, the environment can be constituted by the environment of the container treatment unit or the inside of an insulator, i.e. of a clean room. In general, the pressure of the environment will be equal to the atmospheric pressure. The treatment station can, for instance, be a filling station for filling of the containers, a molding machine, in particular, a blow molding machine, one of the form filling machines already mentioned, a coating station or a similar device. Accordingly, the treatment process to be performed can comprise filling of the container with a filling product, in particular, a liquid food product, molding of a plastic container by means of a blowing process or stretch blowing process, molding and simultaneous filling of a plastic container with a liquid filling product, which is equally used for molding, a vacuum-based coating process or the like.
In principle, the mentioned processes are known in the state of the art and are therefore not explained in greater detail in this document. We should only point out that the mentioned filling, molding and/or form-filling processes are performed to support and/or accelerate the process in a partial vacuum, i.e. with negative pressure. In the following, the term “vacuum” is used for the sake of simplicity, even if a significant residual pressure remains in the vacuum area. The filling process can be accelerated, for example, by evacuating the inside of the container to be filled prior to the filling process. This can be done in particular by filling the container to be filled in a closed chamber that has been evacuated Likewise, a blow molding and/or stretch blowing process can be supported by means of creating a vacuum between the preform and the internal wall of the blow mold. The same applies for a form-filling process in which both the inside of the preform to be filled as well as the space between the preform and the internal wall of the blow mold can be evacuated. In particular, the form-filling process can also be performed in a vacuum chamber that is designed precisely for this purpose.
According to the disclosure, the vacuum area is sealable, i.e. the vacuum area designates a sealed, pressure-tight volume with one or several apertures that can be sealed in a pressure-tight way. For this purpose, the apertures are equipped in particular with a controllable or adjustable sealing system such as an adjustable valve, an adjustable flap, an adjustable slider or the like. Other options are possible and known in the state of the art. The only decisive factor is that the aperture or the apertures can be closed and reopened in a controlled way so that there is a controlled atmosphere within the vacuum area. Opening and closing of the sealing systems, in particular of the adjustable valves, thereby occurs by means of a control and/or regulating unit that is configured such that a vacuum created in a vacuum area is in part transferred to another vacuum area and/or to the central vacuum accumulator. According to the disclosure, the vacuum areas are therefore connected to each other and/or to the central vacuum area through a plurality of connection lines that can be opened and closed by means of switching of sealing systems to be installed at or in the connection lines. Hence, pressure equalization between two vacuum areas and/or a vacuum area and the central vacuum accumulator can therefore be ensured through systematic opening and closing of the appropriate valves. For the sake of simplicity, the alternative sealing devices described above shall always be implied when we speak about valves.
A partial recycling of a vacuum in a vacuum area occurs, according to the disclosure, by bringing the evacuated vacuum area systematically in hydrodynamic contact with a further vacuum area in which there is a higher pressure through one of the connection lines. Thereby, gas flows from the further vacuum area into the evacuated vacuum area whereby the pressure in the further vacuum area decreases. Hence, partial evacuation of the further vacuum area can be ensured through opening the connection lines so that the required energy of a vacuum pump for evacuation of the further vacuum area can be reduced to a desired target pressure.
The plurality of the treatment stations can in particular be equal treatment stations for performing equal treatment processes. For example, the plurality of equal treatment stations can be arranged on a rotating support wheel of a rotary carousel in order to continuously perform a treatment process on a plurality of containers. Since the process as described above occurs under vacuum conditions, the respective vacuum area has to be evacuated to the desired negative pressure after insertion of the container or preform to be treated, which generally occurs by means of a vacuum pump. To take out the treated container, the vacuum area then has to be ventilated to environment pressure if not the entire treatment unit should work under vacuum conditions, which can only be realized with a very high effort in terms of process technology and plant engineering. The device according to the disclosure therefore enables partial conservation of the vacuum that exists in the vacuum area prior to the ventilation process by using the negative pressure for partial evacuation of a further vacuum area, which has been closed in a pressure-tight way after insertion of a container and/or preform, in preparation of the treatment process to be performed. This can be done directly or indirectly, for example through the central vacuum accumulator mentioned before.
The connection lines can thereby be designed in a way that, depending on the number of treatment stations and the configuration of the plant in terms of process technology, suitable vacuum areas are connected to each other and/or to the central vacuum accumulator. The connection lines can for example be created with pipes, dimensionally stable hoses or similar equipment.
According to an embodiment, the device can further comprise a plurality of switchable valves that are arranged at the interfaces between the vacuum areas and the connection lines, whereby the control and/or regulating unit as described above is designed for controlled opening and closing of the switchable valves. Thereby, the volume of the vacuum areas is defined by the arrangement of the switchable valves. To minimize the dead space volume of a connection line between a vacuum area and a central vacuum accumulator, the switchable valve can be arranged for example directly on a chamber of the vacuum area to be evacuated (see below). In case of connection lines between two equal vacuum areas, a central arrangement of the valve between the two vacuum areas or the inclusion of a separate valve directly on the chamber of the respective vacuum area is an option. In the latter embodiment, the dead storage volume can be further reduced during evacuation of the respective chambers to the target pressure as the volume of the connection lines can be omitted in this evacuation step.
According to an embodiment, the vacuum areas can be connected to each other in pairs. The connection lines can thereby be arranged in a way that each vacuum area to be evacuated is connected to one of the vacuum areas to be ventilated. In doing so, one vacuum area can also form a pair with more than one further vacuum area. If the numerous treatment stations are arranged in the periphery of a rotary carousel, the associated vacuum areas can for example be connected to each other in a “crosswise” way. The pairs of interconnected vacuum areas consequently form a sort of vacuum swing, in which a part of the vacuum is always “passed on” to the respective vacuum area to be evacuated. Hence, a part of the energy that is used to create the vacuum can be recycled. However, as the pressure of the communicating pair of vacuum areas exceeds the desired target pressure after the pressure equalization, re-pumping by means of a vacuum pump is required. This can though be done indirectly through the central vacuum accumulator.
According to another embodiment, the central vacuum accumulator can therefore comprise for example a main accumulator that is connected to a vacuum generator, in particular, by means of a vacuum pump. Vacuum pumps are well known in the state of the art and are consequently not explained any further in this document. The connection of the central vacuum accumulator, in particular, the main accumulator, with the vacuum pump can be opened and closed by means of a switchable valve. The switchable valve can thereby, just as the vacuum pump itself, be controlled or regulated by the control and/or regulating unit. When the valve is open, the pressure in the main accumulator is reduced to a predefined first pressure that can be chosen in a way that the desired target pressure can be set in a vacuum area that is connected to the main accumulator.
This can be done either while the valve is open, so that the vacuum pump evacuates the vacuum area that is connected to the main accumulator through the respective connection line, or while the valve is closed, whereby a lower respective pressure has to be set in the main accumulator due to the pressure equalization through the connection line before opening the connection line. It is clear that the main accumulator is preferably connected to each vacuum area by means of a separate connection line, each of which is equipped with a switchable valve. By means of opening of several valves, several vacuum areas can also be evacuated simultaneously, if required. For the connection lines between the vacuum areas and the main accumulators, a switchable valve is generally sufficient, which is preferably arranged at the interface between the vacuum area and the connection line (see below).
Also the main accumulators can be used in the same way for partial recycling of a vacuum in a vacuum area. For this purpose, the switchable valves between the vacuum area and the main accumulator can be opened for partial ventilation of the evacuated vacuum area in order to create a pressure equalization between the main accumulator and the vacuum area. After the valve is closed again, the pressure equalization described above can optionally be done in another vacuum area to be evacuated. Then, the vacuum area that has already been partially ventilated this way can be opened, while the vacuum area that has already been partially evacuated can be set in communication with the main accumulator for the purpose of pressure equalization. A part of the gas that flows into the main accumulator due to this pressure equalization can thereby be sucked back out of the main accumulator by means of opening the connection line to another evacuated vacuum area. Consequently, the vacuum pump only has to be used for correction of the predominant pressure in the main accumulator due to the difference between the equalized pressure during communication with the evacuated container and the predetermined first pressure, whereby the energy requirement of the vacuum pump can be significantly reduced.
According to another embodiment, the central vacuum accumulator can further have at least one recycling accumulator that is connected to the main accumulator and/or a recycling accumulator by means of one or several sealable connection lines, whereby the vacuum areas are connected both with the main accumulator as well as with each of the recycling accumulators. The recycling accumulator that is connected to the main accumulator forms a vacuum swing, due to one or several switchable valves that are to be installed in the respective connection line, that works as already described several times. The purpose of a further accumulator in the shape of the recycling accumulator thereby consists of a phased recycling process of the vacuum in a vacuum area in the way that has already been described above in connection with the combination of the main accumulator with a pair of vacuum areas. Hence, the recycling accumulator is to be installed in order to store a second pressure that is higher than the first pressure but lower than the equalization pressure between the vacuum areas of the pair. The valves of the connection lines are thereby switched in a way that an evacuated vacuum area for vacuum recycling is short-circuited first with the main accumulator, then with the recycling accumulator and optionally last with the vacuum area of the pair to be evacuated. Conversely, the vacuum area to be evacuated is short-circuited first with the vacuum area of the pair that has already been partially ventilated if the respective connection in pairs is planned. Subsequently, the vacuum area to be evacuated is short-circuited first with the recycling accumulator and only then with the main accumulator. The valves of the connection lines that are not needed for short-circuiting are thereby generally closed in order to enable a systematic pressure equalization. Depending on the configuration of the device, the connection of the vacuum areas in pairs can be omitted, in particular, if there are only a few and not equal treatment stations. In this case, the respective steps are not relevant.
Through systematic opening of the valve(s) between the main accumulator and the recycling accumulator, a pressure correction can be performed, if required, in the recycling accumulator in a way that is equivalent to the abovementioned pressure correction in the main accumulator.
According to a special embodiment, the central vacuum accumulator can comprise a plurality of recycling accumulators that are connected to each other in series to store a plurality of negative pressures that decrease in a cascade-like manner. Hence, one of the recycling accumulators that are interconnected in series is connected to the main accumulator while the remaining recycling accumulators are interconnected like in a serial circuit. Just as in the abovementioned embodiment, each of the recycling accumulators is connected to each of the vacuum areas by means of a connection line. Through installation of switchable valves at the relevant places in the connection lines, a pressure equalization can be achieved systematically between two recycling accumulators and/or between the vacuum areas and the recycling areas. The same applies for the connection of one of the recycling accumulators with the main accumulator.
The serial circuit of recycling accumulators can thereby be used to store a plurality of negative pressures that decrease in a cascade-like way. For example, the lowest pressure of the cascade can be stored in the first recycling accumulator that is connected to the main accumulator, whereby the operation of this partial system occurs in the same way as described with regard to the above embodiment. The next recycling accumulator that is connected to the first recycling accumulator in series can then be used to store a higher pressure than in the first recycling accumulator, whereby this pressure is once again lower than the pressure of the next link in the series that has to be stored. Hence, the pressure to be stored increases in a phased way along the series of recycling accumulators from the main accumulator up to the last recycling accumulator of the series.
To operate the overall system, the main accumulator is at first connected to the respective evacuated vacuum area to be ventilated in order to recycle the lowest pressure of the system in the main accumulator. Subsequently, the increasingly ventilated vacuum area is successively connected to the recycling accumulators along the series, i.e. with increasing pressures to be stored, so that the vacuum that exists in the vacuum area to be ventilated can be recycled. Conversely, a vacuum area to be evacuated is at first connected to a recycling accumulator at the end of the series, i.e. with the recycling accumulator to store the highest pressure, in order to perform a first evacuation step. Then, the vacuum area to be evacuated is connected consecutively to the recycling accumulators of the series in the order of the decreasing pressures in order to evacuate the vacuum area step by step. Finally, the vacuum area that has already been evacuated to a large extent is connected to the main accumulator in order to evacuate the vacuum area to the target pressure. As already mentioned above, the pressure existing in the respective recycling area can be corrected to the pressure that is required for the respective evacuation step by means of connecting the recycling accumulators in pairs among each other and/or by connecting the first recycling accumulator to the main accumulator. This can be done both starting from the main accumulator as well as starting from the last recycling accumulator of the series through successive, pair-wise pressure equalization between respectively two accumulators.
According to an embodiment, the central vacuum accumulator can comprise a circular line that is connected to the plurality of the vacuum areas. Such a circular line can be used for example in case of a plurality of equal treatment stations that are arranged along the periphery of a rotary carousel. The circular line is thereby designed as a continuous space with a well-defined pressure equivalent to the accumulators described above, i.e. the circular line can be separated from the vacuum areas through switchable valves in the connection lines between the circular line and the vacuum areas. There can be a circular line, which is respectively connected to each vacuum area, for each pressure level. In addition, the circular lines can be connected to the main accumulator and the recycling accumulators of the central vacuum accumulator whereby each circular line is associated to one of the accumulators. In a special case, the accumulators can be omitted whereby the circular lines take on the function of the accumulators. Accordingly, the circular lines are connected among each other in the same way as in the serial circuit described above.
According to another embodiment, the volume ratio of the central vacuum accumulator to the vacuum areas can be at least 2:1, preferably at least 3:1, even more preferably at least 5:1. In particular, the volume ratio of the main accumulator and/or the recycling accumulators to the vacuum areas can be dimensioned accordingly. For example, the switchable valves of the connection lines as mentioned above can be arranged directly on vacuum chambers of the vacuum areas and in particular, at the interface between the vacuum areas and the connection lines in order to keep the volume of the vacuum areas to be evacuated as small as possible. As, according to the principle of the vacuum swing described above, there is always a pressure equalization to a value between the two initial pressures of the interconnected volumes, the lower of the two pressures can never be recycled completely. The recycling, however, improves with an increasing volume ratio of the accumulator to the vacuum area to be recycled. Also in case of a vacuum swing between the main accumulator and/or recycling accumulators, the volume ratio can be chosen in a way that the respective accumulator is significantly larger than the vacuum area to be recycled. Very good recycling rates can be achieved with the abovementioned values so that the energy requirement of the vacuum pump for the inevitable pressure corrections can be reduced to a very large extent. The volume ratios mentioned above can also be implemented as vacuum accumulators if circular lines are used. In all cases, the respective accumulator volume can be increased by the respective volume of the connection line by means of arranging the switchable valves at the interfaces of the vacuum areas.
According to an embodiment, the treatment stations can each have one filling unit to fill a container with a filling product within a vacuum chamber whereby the vacuum area comprises the vacuum chamber. As already mentioned above, the filling of containers, in particular, of bottles or cans, can be done under negative pressure in order to accelerate the filling process. Therefore, the container, in particular, a plastic bottle or a metal can, can be arranged in a chamber, that is for example cylindrical and that is shaped as a part of the vacuum areas described above and connected to the connection lines described above. Particularly in case of plastic bottles, the evacuation of the entire chamber is recommended as a pressure difference between the inside and the outside of the bottle would lead to a deformation of that bottle. Depending on the desired negative pressure, the predominant pressure in the vacuum chamber is even lower than the pressure of the environment after filling of the bottle so that the vacuum swing described above can be used. Lower pressures at the beginning of the filling process allow for a further acceleration of the filling process as only a small quantity of residual gas has to flow out of the bottle.
According to an alternative embodiment, the treatment stations can each have a blowing device or form-filling device to mold and/or mold and fill plastic containers within a vacuum chamber whereby the vacuum area comprises the vacuum chamber. Also in the blowing and stretch blowing devices known in the state of the art, the blowing mold can be arranged in a vacuum chamber, which has for example a cylindrical shape, whereby the negative pressure created in the blowing mold supports the molding process of the plastic containers. Even in the abovementioned mold blowing machines, such a negative pressure in a vacuum chamber is useful during the at least partial molding process of the preform into the final plastic container with the product to be filled in. Here, the hollow mold can be arranged additionally in a vacuum chamber. In this case, sealing gaskets of the mold parts that form the hollow mold can be omitted as the internal pressure of the hollow mold communicates with the internal pressure of the vacuum chamber through appropriate apertures of the hollow mold. If pressure-tight hollow molds are used, the vacuum area can also be defined by the hollow mold itself. In this case, the hollow mold has one or several boreholes through which it is connected to the connection line(s). Also in this case, the partial vacuum that exists in the boreholes and in the interfaces to the connection lines can be recycled.
According to another embodiment, the vacuum area can further comprise a dead space volume of the connection lines. A dead space volume of a vacuum area in this context is to be understood particularly as the volume of the feed lines or the like between the switchable valve and the actual process chamber, for example the vacuum chamber or the hollow mold. Depending on the configuration of the treatment station, this dead space volume can be significant so that recycling of the partial vacuum that exists in it comes with energetic benefits.
The problems mentioned above are also solved by a process for partial recycling of a vacuum in a container treatment system with a plurality of treatment stations, that each have a sealable vacuum area, which includes the following steps: evacuating a first vacuum area to a first pressure; performing a treatment phase on a container within the first vacuum area; and ventilating the first vacuum area for removal of the treated container, whereby a connection to the pressure equalization between the first vacuum area and a second vacuum area is produced with a second, higher pressure and/or a central vacuum accumulator prior to ventilation of the first vacuum area.
In this context, the same variations and embodiments as described above in connection with the vacuum recycling unit according to the disclosure can also be applied to the process for partial recycling of a vacuum. In particular, the processes described above in connection with the operation of a vacuum swing can be applied to the process for partial recycling of a vacuum.
The treatment stations can in particular be the filling devices, blowing and stretch blowing devices or form-filling machines described above. Accordingly, the treatment phase can be the filling process of a bottle, in particular a bottle or can, with a filling product such as a beverage, the blow molding and/or stretch blow molding process of a plastic container such as a PET bottle, as well as the molding and filling process of a plastic container within a hollow mold through filling with the essentially liquid product. Prior to the evacuation of the vacuum area, the container or preform to be treated can be inserted in the vacuum area, for example a vacuum chamber or a hollow mold, which is then sealed in a pressure-tight way. For this purpose, a lock can for example be provided for. Subsequently, the first vacuum area is evacuated to the first pressure which can be—depending on the treatment step—in the range from 0.1 to 0.9 bar, preferably from 0.3 to 0.8 bar, even more preferably from 0.5 to 0.7 bar. It should be pointed out that the predominant pressure in the vacuum area can be changed, and in particular, increased, by performing the treatment step. Here and in the following sections, the pressure existing after the treatment step is set as equivalent to the first pressure and/or target pressure after the evacuation of the vacuum area for the sake of simplicity. In case of a pressure that is modified by the treatment step, the subsequent predominant negative pressure can of course be recycled equivalently whereby an additional pump capacity will though be required to compensate the pressure modification by the treatment.
To take out the treated container, the vacuum area necessarily has to be opened so that the partial vacuum that exists in it is ventilated. According to the disclosure, a connection to the pressure equalization between the first vacuum area and a second vacuum area with a second, higher pressure and/or a central vacuum accumulator is therefore created prior to ventilation of the first vacuum area as described in detail above. In particular, the vacuum areas can be the vacuum areas of a plurality of equal treatment stations. The second, higher pressure can in particular be the environment pressure that exists in the second vacuum area after inserting the container or preform to be treated in this second vacuum area. Hence, a partial evacuation of the second vacuum area is implemented due to the pressure equalization between the first and second vacuum area, whereby the partial vacuum that exists in the first vacuum area is partially recycled. The pressure equalization occurs, as described above, in a controlled way by means of controlled and/or monitored opening and closing of respective valves that are to be installed on the connection lines. A control and/or regulating unit for this purpose can therefore control and/or monitor a plurality of switchable valves.
In addition or as an alternative, a part of the vacuum can also be recycled through pressure equalization with a central vacuum accumulator as described above. Also for this purpose, a control and/or regulating unit systematically opens and closes the respective valves on the connection lines between the central vacuum accumulator and the plurality of vacuum areas.
The vacuum of the first vacuum area that is “partially stored” in the central vacuum accumulator can be partially transferred, according to an embodiment, to the second vacuum area by means of creating a connection to the pressure equalization between the second vacuum area and the central vacuum accumulator. Thereby, a vacuum area to be evacuated as mentioned can already be evacuated in part. A vacuum pump that is connected to the central vacuum accumulators will then only have to equalize the differential pressure to the target pressure. As described above, however, also the pressure of the central vacuum accumulator can at first be reduced by means of the vacuum pump to a pressure that is lower than the target pressure to an extent that a pressure equalization between the central main accumulator and the second vacuum after separating the central vacuum accumulator from the vacuum pump leads to the desired target pressure. Further embodiments such as the combined recycling by means of consecutive pressure equalization processes between the first vacuum area and the second vacuum accumulator and between the first and the second vacuum areas as described above are also possible.
According to another embodiment, the creation of the connection between the second vacuum area and the central vacuum accumulator can comprise the successive creation of a connection between the second vacuum area and at least one recycling accumulator of the central vacuum accumulators with a third pressure that is lower than the second pressure, and a connection between the second vacuum area and a main accumulator of the central vacuum area with a fourth pressure that is lower than the third pressure. Hence, the vacuum recycling as described in detail above takes place in two or more steps whereby the third pressure of the recycling accumulator is higher than the fourth pressure of the main accumulator. The latter is ultimately responsible for the evacuation of the second vacuum area that is to be evacuated to the target pressure. As described above, also a cascade-like recycling process of the vacuum can be implemented by means of a serial circuit of several recycling accumulators. Therefore, the vacuum area to be evacuated and/or the evacuated vacuum area are connected successively to the main accumulator and the recycling accumulators for pressure equalization, whereby the order of the connections for the vacuum area to be evacuated is inverted in relation to the order of the connections for the evacuated vacuum area. Further, the process for vacuum recycling by means of the main accumulator and the recycling accumulator(s) can also be combined with the pair-wise vacuum swing between equal vacuum areas.
According to a special embodiment, the process can further comprise the evacuation of the main accumulator of the central vacuum accumulator to the fourth pressure. This evacuation can occur through systematic connection of the main accumulator to the vacuum pump. Thereby, the fourth pressure, as mentioned, can be lower than the target pressure. The evacuation of the main accumulator to the fourth pressure thereby compensates the insufficient recycling of the vacuum of the first vacuum area due to the limited volume ratio between the vacuum accumulator and the vacuum area. Due to the vacuum swing, this necessary pressure correction has a significantly smaller extent than without the vacuum recycling process so that the energy requirement of the vacuum pump can be significantly reduced.
Instead of the described processes and devices, the preforms can also be created directly by an upstream injection-molding machine and transported to the forming and filling unit while they are still heated. In energetic terms, this is advantageous as a part of the heat is not lost to the environment. Possibly, however, there must be an intermediate conditioning unit that adjusts the temperature of the preforms only to a minor extent (less than plus or minus 50° C.) and/or that creates a temperature profile. If the preforms are injection-molded within a clean room, no further sterilization of the preforms may be required if the clean room extends up to a position in which a seal can be superimposed on the container after filling.
In particular, the production and/or expansion and the filling of the containers take place within a space with a low-contamination environment. The low-contamination environment, which is in particular a clear room, can be created by one or combinations of the following measures:

- The low-contamination environment of the unit (within a machine protection) is set under overpressure in relation to the surrounding atmosphere by means of blowing filtered air through fine filters into the room, at least during the production process.
- The drives for a plurality of movements of the cavity are arranged outside of the clear room, i.e. for example the drives for opening and closing of the cavity (mold) and/or for the movement of a stretching rod and/or for lifting or lowering of a container and/or the movement of a blowing or filling nozzle.
- The inner walls of the room are cleaned and/or sterilized in regular intervals, for example through spraying or steaming with caustic solution, acid, disinfection liquid, hydrogen peroxide (gaseous or liquid). In particular, the internal and external sides of the cavities, blowing and filling nozzles and the stretching rods are included in the cleaning and/sterilization process. In particular, the inner walls of the machine protection are also included.
- The low-contamination environment is sealed against the surrounding atmosphere. In a rotary carousel, the sealing gasket can be a surge tank or a rubber seal that seals the rotating part in relation to the fixed part of the device.

In particular, the containers and/or preforms are sterilized prior to insertion in the low-contamination environment.
In the device and the process, other containers such as cans, bags or other containers that can be easily reshaped by hand can also be treated.
The product to be bottled (water, coke) can also be transported to the treatment stations in a distributor, in particular in a circular line. There is in particular an overpressure in the distributor in order to fill up the product even faster. In particular, there is an overpressure of 1.1 to 10, preferably between 2 and 5 bar.
The product is transported in particular, through a rotary distributor from a stationary part of the machine into a rotary part of the machine (support wheel).
In the rotary distributor, there can be further tracks besides the product, for example one for the vacuum if the pump is arranged in the stationary part of the unit.
If the device is a form-filling machine, there can also be another track for a gas with overpressure to mold the containers.
Equally, a track to feed back gas (recycling) or to clean media (CIP) can be included.
From the rotary distributor, the media are distributed in particular among individual treatment stations. This can be done by means of circular lines that are connected to the rotary distributor and from which lines branch off in a star-shaped way to the individual stations or by means of a central tank that is connected to the rotary distributor and from which individual lines are led to the stations in a star-shaped way.
In case of a rotary carousel, in particular, an input star wheel and an output star wheel are to be installed in its periphery to transport containers to the rotary carousel and/or to take containers out of the rotary carousel. On the rotary carousel, containers are in particular only treated during an angle of 270° to 350°, depending on how closely the input and the output star wheel can be positioned next to each other.
In particular, within the first 20°, in particular, 10°, of the treatment angle, the vacuum area of a treatment station is partially evacuated to a first pressure through the connection of the area to a vacuum area of another treatment station. Then, the vacuum area is evacuated to a second pressure, which is lower than the first pressure, during a treatment angle of further 20°, preferably 10°, notably through connection of the vacuum area to the vacuum pump.
The transportation path of the containers is in particular meander-shaped.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and exemplary variants, as well as advantages of the present disclosure, are explained in greater detail by means of the following drawings. It is clear that the variants are non-exhaustive examples of the field of the present disclosure. Further, it is clear that some or all of the characteristics described in the following can also be combined with each other in a different way.

FIG. 1 shows a schematic top view of an exemplary variant of a rotary carousel with a plurality of equal treatment stations.

FIG. 2 shows a lateral view of an exemplary variant of a treatment station designed as a form-filling machine.

FIG. 3 shows a lateral view of another exemplary variant of a treatment station designed as a form-filling machine.

FIG. 4 shows an exemplary variant of a vacuum recycling unit with pairs of vacuum areas and a central vacuum accumulator.

FIG. 5 shows an alternative variant of a vacuum recycling unit with a main accumulator and a recycling accumulator as part of the central vacuum accumulator.

DETAILED DESCRIPTION

In the following, equal or similar elements are indicated with the same reference signs. A repeated description of these elements is omitted for the sake of clarity. In addition, it is clear that some or all elements in the following variants can be replaced by or combined with similar elements that are described in connection with other variants.
FIG. 1 shows a schematic top view of an exemplary variant of a rotary carousel with a plurality of similar treatment stations. The device can be used preferably for the production of or for the production and simultaneous filling of plastic containers. For example, a plurality of treatment stations 105 in the form of the form-filling machines described below can be arranged alongside the circumference of the rotary carousel 104 and circulate with the latter. Each of the circulating treatment stations thereby comprises a hollow mold 106 for molding and filling of the plastic containers. Molding and filling of the plastic containers can be supported, as described above, through the creation of a partial vacuum. For this purpose, the treatment stations have individual vacuum areas.
The system is to be equipped in particular, with a plurality of forming and filling stations that are arranged particularly on the outer circumference of a continuously circulating rotary carousel. The rotary carousel is preferably a wheel.
The rotary carousel rotates particularly around a vertical axis whose prolongation intersects with the grounding center.
In particular, the stations are all arranged with an equidistant spacing towards each other. In particular, the stations have cavities in which the containers can be expanded against the inner walls of the cavity so that the readily shaped containers can have the (negative) shape of the inner walls of the cavity.
The preforms 103 schematically displayed in the figure pass through a furnace 107, for example an infrared furnace or a microwave furnace in which the preforms 103 are heated with a desired temperature profile alongside their longitudinal axis. While the microwave furnace is preferably a rotary carousel, the preforms are transported along a straight line, at least for a part of the way, in case of the infrared furnace. The heated preforms 103 are then transferred to the rotary carousel 104 through an input star wheel 108 and in particular, inserted into the opened hollow molds 106 in the process. Therefore, the hollow molds 106 have to be ventilated to the pressure of the environment. During circulation around the rotary carousel 104, the preforms are molded and filled within the closed and partially evacuated hollow molds 106 of the treatment stations 105. Prior to the transfer to an outlet star wheel 109, the hollow molds are opened again so that the plastic containers, that are now completely molded and filled, can be taken out. The temperature profile applied in the furnace 107 can thereby be predetermined as a function of the desired shape of the plastic container and its material. Furnaces to pre-heat preforms are sufficiently known in the state of the art and are therefore not described further in this document. From the outlet star wheel 109, the finished and filled containers 102 can be transferred to a conveyor belt for further treatment.
In particular, the containers are planned to be sealed while they are still in this cavity. Therefore, a sealing feed system can be installed on the periphery of the rotary carousel.
FIG. 2 shows a lateral view of an exemplary variant of a treatment station designed as a form-filling machine. The form-filling machine comprises a mold that is designed as a hollow mold whereby the mold in the variant that is shown here as a non-exhaustive example consists of two side parts 106 a and 106 b, which can be moved and/or tilted along the direction of the arrow by means of a multi-part mold support 110, and a floor part 106 that can be moved along the direction of the arrow. After inserting a preform 103, the mold will be sealed by means of merging the mold parts 106 a-c as generally known.
The mold can thereby be designed in a way that it seals with the preform 103 in a pressure-tight manner and hence forms a pressure-tight hollow mold 106 that can be evacuated by means of a media distributor 119, for example a joint rotary distributor for the plurality of treatment stations, through vacuum lines 118 and boreholes in the hollow mold to support the molding process to a negative pressure.
Alternatively or in addition, the hollow mold 106 can be arranged inside a vacuum container (not shown), which can be evacuated through the vacuum lines 118.
Pressure pads to hold the mold shells of the hollow mold together during the molding process, a support for the mold shells and/or connections for the temperature control of the mold shells or the support can be arranged within this vacuum container. In particular, the vacuum container can be equipped with at least two mobile parts. In particular, these mobile parts can be coupled with the drives of the support for the mold shells for insertion and removal. In particular, the supports are fastened tiltably on a shaft and can be opened in a book-like way.
The vacuum lines 118 are a schematic variant of the connection lines described above whereby the rotary distributor 119 can be connected for example to a circular line as a central vacuum accumulator.
The present disclosure, however, is not limited to the variant that is shown as an example in this document but comprises particularly the arrangements described below. The hollow mold 106, including the dead space of the connection lines 118, optionally together with a vacuum chamber thereby forms the vacuum area of a form-filling machine whose partial vacuum needs to be recycled.
In the form-filling process, a fluid nozzle of a valve block 111 can, by means of a linear process according to the blowing nozzle known in the state of the art, be set in a pressure-tight way onto the outlet area 121 of the preform through which the media and/or the filling products can be injected and/or blown into the preform and/or the plastic container to be molded, respectively with the desired pressure. For this purpose, the valve block 111 is connected to the media distributor 119 by means of a feed line for a molding fluid 114 and/or a feed line for a filling product 115. Adjustable valves in the valve block 111 thereby control the supply of molding fluid and/or filling product. The molding fluid can be a gaseous medium that is compressed to the pressure that is required for molding the preforms, for example by means of a compressor 120. Alternatively, the molding fluid can also be a filling product. Also in this case, a suitable overpressure can be created in the fluid, in particular, as a function of the material to be molded and the filling product. The same applies for the filling product in the feed line 15 whereby, according to an embodiment, a part of the molding of the container can be done with this filling product.
For stretch molding, the form-filling machine that is shown here as a non-exhaustive example can further have a stretching rod 113 that can be moved into the preform along the displayed arrow direction in order to stretch the preform to its target length that is equivalent to the height of the finished plastic container. If a trepanned stretching rod 113 is used, medium or filling product hat has already been filled in can further flow back out of the container or be actively removed through a connection to the media distributor 119 that is shown as an exemplary suction line 116 in this document. Also, the stretching rod 113 can be used for filling and/or further molding of the container. Therefore, the stretching rod 113 can have an aperture on its end that faces the hollow mold and/or apertures arranged alongside its longitudinal direction. The latter can be used in particular, for effective mixing of warm and cold filling product.
It is clear that the arrangement shown in FIG. 2, in particular, the vacuum lines, is only an exemplary embodiment. A plurality of alternative embodiments, of which some will be explicitly described in the following, are possible.
The devices and processes for vacuum recycling described above can also be used in combination with a plurality of (only) filling devices as treatment stations 105 on a support wheel of a rotary carousel 104. For example, FIG. 3 shows a side view of an exemplary variant of a treatment station designed as a filling device. Through vertical movement of the container 302 to be filled, a vacuum chamber 340, which has for example a cylindrical shape and which is pressure-tight due to sealing gaskets 330 and in which the container can be filled particularly fast under negative pressure, is formed.
Therefore, the vacuum chamber 340 that is now sealed is evacuated to the desired target pressure and filling product is subsequently filled into the container through the feed line 335 with a filling valve. In the embodiment that is shown here as a non-exhaustive example, the vacuum chamber 340 has three connection lines through which the desired target pressure can be created in the vacuum chamber. A first connection line 350 connects the vacuum chamber to another vacuum chamber (not shown) to be able to create a pressure equalization in the formed pair of vacuum areas that comprise the respective vacuum chambers. A second connection line 360 a can be installed for example in order to connect the vacuum chamber 340 as described above to the main accumulator of a second vacuum accumulator. Finally, there can be a third connection line 360 b to connect the vacuum chamber 340 to a recycling accumulator of the central vacuum accumulator. Further connection lines, for example to other recycling accumulators and/or further vacuum chambers, are possible. Equally, individual ones of the abovementioned connection lines can be omitted.
The connection lines 350, 360 a and 360 b are equipped with switchable valves (not shown) that are preferably arranged directly on the vacuum chamber 340, for example on the wall of the vacuum chamber. Thereby, the dead space volume of the feed lines to the vacuum chamber can be reduced and a better volume ratio between the vacuum accumulator and the vacuum area can be created. By means of a control and/or regulating unit (not shown), the valves can be opened and closed individually and systematically so that a systematic pressure equalization between the vacuum area, that comprises the vacuum chamber 340, and a further vacuum area and/or the central vacuum accumulator can be ensured.
FIG. 4 shows an exemplary variant of a device for vacuum recycling with pairs of vacuum areas and a central vacuum accumulator. According to this variant, each vacuum chamber comprises two connection lines. The connection lines 450 illustrated with dotted lines respectively connect two vacuum chambers that are located opposite to each other alongside the circumference of the rotary carousel while the connection lines 460 illustrated with solid lines connect the vacuum chambers to a central vacuum accumulator in the form of a main accumulator 470. An arrow indicates the direction of rotation of the vacuum chambers.
As schematically illustrated by another arrow, a container to be treated is transferred to an opened vacuum chamber 440-4 to which the pressure of the environment is applied. After closing the vacuum chamber 440-2, it is partially evacuated through the connection line 450 to the opposite vacuum chamber 440-1. As there is still a partial vacuum in the vacuum chamber 440-1 even after performing the treatment step, the pressure in the vacuum chamber 440-2 to be evacuated as described in detail above can be reduced by means of a pressure equalization with the vacuum chamber 440-1 so that the partial vacuum that exists in the vacuum chamber 440-1 can be partially recycled.
Prior to this pressure equalization with the vacuum chamber 440-2, however, the connection line 460 between the vacuum chamber 440-1 to be ventilated and the main accumulator 470 of the central vacuum accumulator can be opened as the pressure within the main accumulator 470 according to the disclosure is lower than the equalization pressure of the pair of vacuum chambers 440-1 and 440-2. This way, the partial vacuum that exists in the vacuum chamber 440-1 can be recycled more effectively in two steps than if there was only a pressure equalization between the vacuum chambers 440-1 and 440-2.
Accordingly, a pressure equalization between the vacuum chamber 440-2, which will then have already been partially evacuated, and the main accumulator 470 can occur after a finished pressure equalization between the vacuum chambers 440-1 and 440-2 by means of opening the appropriate connection line 460. As described above, the pressure in the main accumulator 470 is adjusted in a way and/or the main accumulator 470 is connected with a vacuum pump (not shown) in a way that the desired target pressure is achieved in the vacuum chamber 440-2 through pressure equalization. The vacuum chamber 440-3, which is now partially ventilated, is subsequently opened in order to be able to remove the treated container as indicated by the arrow in the figure.
In the variant that is illustrated in this document as a non-exhaustive example, the vacuum chambers are respectively connected to the opposite vacuum chamber so that separate pairs of vacuum chambers are formed that only communicate indirectly with the main accumulator 470 through their connection lines 460. However, alternative embodiments are also possible, in which the vacuum chamber is connected to more than one other vacuum chamber in order to form groups of vacuum chambers. Also, the pair does not necessarily have to consist of opposite vacuum chambers as long as one vacuum chamber to be ventilated can be connected to a vacuum chamber to be evacuated. The provision of separate connection lines 460 with the main accumulator 470 is though advantageous as this can lead to an increased volume ratio of the vacuum accumulator to the vacuum area if the switchable valves are arranged on the vacuum chambers. Unlike the illustration in the figure, the main accumulator 470 can in particular, be arranged symmetrically in relation to the vacuum chambers so that the respective connection lines 460 have an equal length.
FIG. 5 shows an alternative variant of a device for vacuum recycling with a main accumulator 570 and a recycling accumulator 580 as part of the central vacuum accumulator. In the illustrated, non-exhaustive variant, no connection lines are to be installed between the vacuum chambers. However, it is clear that the displayed variant, as described above, can be upgraded with such connection lines to form pairs of vacuum chambers.
In the illustrated embodiment, the central vacuum accumulator comprises a main accumulator 570 and a recycling accumulator 580. Preferably, the main accumulator 570 and the recycling accumulator 580 are connected to each other by means of a connection line for controlled pressure equalization (not shown) through which the pressure in the recycling accumulator 580 can be corrected. As described above, there can also be several recycling accumulators that are connected to each other in a serial circuit and whose first recycling accumulator is connected to the main accumulator 570. Accordingly, there will be further connection lines between the recycling accumulators and the vacuum chambers. As explained above, a cascade of decreasing pressures can be stored with a series of recycling accumulators in order to make the evacuation of the vacuum chamber 440-2 to be evacuated as efficient as possible.
As shown in FIG. 4, a container to be treated is inserted in the open vacuum chamber 440-4 that is subsequently closed. The vacuum chamber 440-2, which is then closed, is partially evacuated by means of a first pressure equalization through a connection line 560 b, which is illustrated with a dotted line, with the recycling accumulator 580 as there is a higher pressure in the recycling accumulator 580 than in the main accumulator 570 according to the disclosure. Afterwards, the partially evacuated vacuum chamber 440-2 is evacuated to the target pressure through a connection line 560 a, which is illustrated with a solid line, with the main accumulator 570 whereby a vacuum pump that is connected to the main accumulator can be used.
Conversely, the evacuated vacuum chamber 440-1 is connected in a first ventilation step through the connection line 560 a with the main accumulator 570 in order to partially recycle the vacuum that exists in the vacuum chamber in the main accumulator in which there is a lower pressure than in the recycling accumulator 580. Subsequently, the vacuum chamber 440-1 that has already been ventilated partially is connected through the connection line 560 b with the recycling accumulator 580 in order to recycle a further part of the partial vacuum. Finally, the vacuum chamber 440-3 is opened to take out the treated container. Also in this case, the installation of separate connection lines for each vacuum chamber is beneficial, whereby the main accumulator 570 and the recycling accumulator 580 can in particular, be arranged symmetrically in relation to the vacuum chambers in order to create connection lines 560 a and/or 560 b with equal lengths.
The illustrated embodiments enable a partial recycling of a vacuum chamber to be ventilated as ventilation occurs in part through pressure equalization with a central vacuum accumulator and/or a vacuum chamber to be evacuated. Therefore, the energy requirement of a vacuum pump, which eventually evacuates the vacuum chamber to be evacuated to the target pressure, can be reduced. Through phased recycling, the recovery of the vacuum pump power can be improved, whereby in particular, a high volume ratio between the vacuum accumulator and the vacuum chamber is advantageous. Through arrangement of the valves on the vacuum chambers, the volume of the required connection lines can be added almost entirely to the accumulator volume. A circular line can enable a symmetrical distribution of the volumes of the connection lines in a convenient way.

Claims

1. A device for vacuum recycling in a container treatment unit, comprising:

a plurality of treatment stations that each have a sealable vacuum area,

a plurality of connection lines that connect the vacuum areas to each other and/or to a central vacuum accumulator, and

a control and/or regulating unit that is configured such that a vacuum created in a vacuum area is partially transferred to another vacuum area and/or the central vacuum accumulator.

2. The device according to claim 1, further comprising a plurality of switchable valves that are arranged at the interfaces between the vacuum areas and the connection lines whereby the control and/or regulating unit is designed for controlled opening and closing of the switchable valves.

3. The device according to claim 1, and the vacuum areas are connected to each other in pairs.

4. The device according to claim 1, and the central vacuum accumulator comprises a main accumulator that is connected to a vacuum generator.

5. The device according to claim 4, and the central vacuum accumulator further comprises at least one recycling accumulator, that is connected to the main accumulator and/or a recycling accumulator via one or several sealable connection lines, and whereby the vacuum areas are connected to the main accumulator as well as to each of the recycling accumulators.

6. The device according to claim 5, and the central vacuum accumulator comprises a plurality of recycling accumulators, which are connected to each other in series, to store a plurality of negative pressures that decrease in a cascade-like way.

7. The device according to claim 1, and the central vacuum accumulator comprises a circular line that is connected to the plurality of vacuum areas.

8. The device according to claim 1, and the volume ratio of the central vacuum accumulator to the vacuum areas is at least 2:1.

9. The device according to claim 1, and each of the treatment stations have a filling device to fill a container with a filling product within a vacuum chamber and whereby the vacuum area comprises the vacuum chamber.

10. The device according to claim 1, and the treatment stations each have a blowing device or a form-filling device for molding and/or molding and filling of plastic containers within a vacuum chamber and whereby the vacuum area comprises the vacuum chamber.

11. The device according to claim 9, and the vacuum area further comprises a dead storage volume of the connection lines.

12. A process for partial recycling of a vacuum in a container treatment unit, comprising:

providing a container treatment unit with a plurality of treatment stations each having a sealable vacuum area;

evacuating a first vacuum area to a first pressure;

performing a treatment step on a container within the first vacuum area;

ventilating the first vacuum area, for removal of the treated container; and

prior to ventilating the first vacuum area, creating a connection for pressure equalization between the first vacuum area and a second vacuum area at a second, higher pressure and/or a central vacuum accumulator.

13. The process according to claim 12, and creating a connection for pressure equalization between the second vacuum area and the central vacuum accumulator.

14. The process according to claim 13, and the creation of the connection between the second vacuum area and the central vacuum accumulator comprises the consecutive creation of a connection between the second vacuum area and at least one recycling accumulator of the central vacuum accumulator at a third pressure that is lower than the second pressure, and a connection between the second vacuum area and a main accumulator of the central vacuum accumulator at a fourth pressure that is lower than the third pressure.

15. The process according to claim 14, and evacuating the main accumulator of the central vacuum accumulator to the fourth pressure.

16. The device according to claim 4, and the vacuum generator comprises a vacuum pump.

17. The device according to claim 8, and the volume ratio is at least 3:1.

18. The device according to claim 8, and the volume ratio is at least 5:1.