DE102009008633B4 - Device for sterilizing containers - Google Patents

Abstract

Device for sterilizing containers (10), with a transport device which transports the containers (10) along a predetermined transport path (P1, P2, P3) and a treatment room (8) in which the containers (10) are sterilized, wherein the transport device (6) transports the containers (10) through this treatment chamber (8), with at least one sterilization device (2) for sterilizing a wall of the containers, with this sterilization device (2) having a generating device (4) for generating charge carriers and a Accelerating device (24) to accelerate the charge carriers generated by the generating device (2) in the direction of the containers (10) located in the treatment space (8), the gas pressure inside the treatment space (8) being below the gas pressure outside the treatment space (8). , characterized in that along the transport path (P1, P2, P3) of the containers (10) through-row me are arranged, with a vacuum in the individual passage rooms towards the actual treatment room (8) increases successively.

Description

The present invention relates to a device for sterilizing containers and a system for treating containers which has such a device for sterilizing containers. In the beverage manufacturing industry, it has become common to produce plastic containers by means of a blow molding process and then with a beverage to fill. Particularly in the case of particularly sensitive beverages such as fruit juices, for example, it is necessary to sterilize the containers produced and, in particular, their inner walls.

Various procedures are known from the prior art for achieving such a sterilization. For example, it is known to charge the containers with a disinfecting gas, for example hydrogen peroxide. Recently, however, efforts have been made to avoid such sterilization methods because of the aggressive gases required.

It is therefore also known from the prior art to use radiation and in particular electron beams to sterilize the containers. As is known from the prior art, such electron radiation devices have a device for generating electrons, such as a heatable tungsten wire, and an acceleration device, which accelerates the electrons generated in this way.

From the EP 19 56 608 A1 are different devices and apparatus for sterilizing the outside - and inside surfaces of plastic containers by means of electron beams are known. The focus of this paper is on the creation or varying arrangement of a magnetic field barrier, based on a large number of connected magnetic fields, with the aspect of reducing the energy loss of the electron beam. This is made possible, among other things, by sterilizing the containers in a vacuum and by arranging the sub-chambers along the transport path.

From the US 2006/01 96 853 A1 a system is known which uses an electron beam for microjoining by means of welding, soldering and/or heating. The basis for this is a device with which the stationary workpiece and its alignment are first focused and imaged using the imaging mode (known from scanning electron microscopy).

From the JP 2002-3 08 229 A a sterilization method and device for containers is known, which is based on uniform irradiation with a low-energy electron beam (30 kV - 500 kV).

However, the problem is also known that when these electrons are accelerated or decelerated in particular, bremsstrahlung in the form of X-rays is produced. This X-ray radiation, in turn, has to be shielded with very complex measures, such as lead sheaths. This shielding in turn makes the systems more expensive as a whole. The amount of shielding material, for example the wall thickness for lead shielding, depends on the acceleration voltage used.

The present invention is therefore based on the object of providing a device for sterilizing containers which, in comparison with the prior art, manages with less expensive shielding measures. Furthermore, it is known that such irradiation devices usually also have exit windows for an electron beam, in particular thin titanium windows. These titanium windows are highly sensitive wear parts because they are made from a very thin layer, and the cooling of the titanium foils, which heat up very quickly, also causes great difficulties.

A further object of the present invention is therefore to dispense with such titanium foils or exit windows as far as possible.

These objects are achieved by the subject matter of the independent claims. Advantageous embodiments and developments are the subject of the dependent claims.

A device according to the invention for sterilizing containers and in particular plastic containers has a transport device which transports the containers along a predetermined transport path. Furthermore, a treatment room is provided in which the containers are sterilized, with the transport device transporting the containers through this treatment room. Furthermore, at least one sterilization device is provided for sterilizing a wall and in particular an inner wall of the containers, this sterilization device having a generating device for generating charge carriers and an acceleration device in order to accelerate the charge carriers generated by the generating device in the direction of the containers located in the treatment room.

According to the invention, the gas pressure inside the treatment room is below the gas pressure outside the treatment room. To put it more precisely, the gas pressure outside the actual sterilization device is also preferably below the gas pressure outside the treatment room and in particular below atmospheric gas pressure. The containers are thus sterilized in a partial vacuum. This has the advantage that the range of the electrons within this partial vacuum is significantly greater than under atmospheric conditions, and in this way, in particular, the acceleration voltage of the sterilization device can also be reduced.

In the device or the sterilization device according to the invention, an electron beam generated by heating a tungsten heating wire is preferably accelerated by a high-voltage potential between a cathode and an anode and focused into a precise beam in a vacuum chamber by an electronic lens system.

Due to the procedure according to the invention, significantly higher jet currents can be achieved, since the sterilization device particularly preferably does not have an exit window such as a titanium window and, in addition, a very fast control of all required parameters is also possible. Furthermore, the process according to the invention can also reduce the throughput time of the material to be irradiated, i.e. the containers, in particular to a period of less than one second, preferably less than half a second and particularly preferably to approximately 0.2 s. This means that fewer treatment stations are required overall.

The gas pressure within the treatment chamber is particularly preferably below 800 mbar, preferably below 500 mbar, particularly preferably below 300 mbar and particularly preferably in a range of approximately 100 mbar.

A further advantage of this arrangement is that wearing parts of the sterilization device can largely be dispensed with. In addition to the cathode, the only wearing part is essentially a screen through which the electron beam emerges from the sterilization device. Such a lower screen is particularly preferably made of molybdenum or similar materials and is particularly preferably encased in copper, with this screen advantageously being cooled. The cooling is used to compensate for heating caused by electrons still striking this aperture.

Furthermore, the necessary acceleration voltage can be lowered to below 100 kV, preferably below 80 kV and particularly preferably to approximately 60 kV by the procedure according to the invention. With such acceleration voltages, expensive lead sheathing for the entire system can largely be omitted.

The device preferably has deflection elements for deflecting the charge carriers. These deflection elements particularly preferably have electrically operated deflection elements and in particular coils. With the help of these coils, the electron beam can also be partially deflected into a desired position inside the container. These deflection elements are particularly preferably arranged below a mouth edge or a mouth of the containers to be sterilized, particularly during operation. To put it more precisely, said deflection elements are provided between the upper edge of the mouth and a base of the containers, for example in the case of other orientations of the containers.

Due to the low acceleration voltages mentioned and the above-described pressure within the treatment room, which is in the range of 100 mbar, the range of the electron beams is still approx. 200 mm, which in principle is sufficient for sterilizing the containers. The shielding of the X-rays, which are very “soft” in this case, is also greatly simplified, so that, for example, steel casings in the range of 5 - 6 mm are sufficient. As mentioned above, no lead sheathing is required.

The efficiency of such an arrangement is similar to that of using a very thin titanium window in the range of approx. 90%, but it also depends on the beam current and the acceleration voltage.

In one embodiment according to the invention, passage spaces through which the containers are guided are arranged along the transport path of the containers, with a gas pressure decreasing within these passage spaces in the direction of transport of the containers to the treatment space. This means that, according to the invention, the actual treatment space in the direction of transport of the containers is not directly adjacent to atmospheric pressure, but rather another lead-through space that is already under a predetermined partial vacuum and possibly also further lead-through spaces are provided, so that the vacuum in the individual lead-through spaces towards the actual treatment room gradually increases. Pump units can be provided in each case be, which act on the individual implementation spaces with a vacuum.

The present invention is also directed to a sterilization device for sterilizing containers and in particular plastic containers. This sterilization device has a generating device for generating charge carriers and in particular electrons. Furthermore, the sterilization device has an acceleration device in order to accelerate the charge carriers generated by the generation device in the direction of containers located in a treatment room, and a housing in which the generation device and the acceleration device are arranged. There is a vacuum inside this housing and an opening is provided through which the charge carriers emerge from the housing.

According to the invention, a radiation path on which the charge carriers travel from the generating device to the container or towards the container is free of material.

It is therefore also proposed with regard to the sterilization device that it does not have an exit window, such as a titanium foil, but that the charge carriers or electrons exit the sterilization device essentially unhindered in order to sterilize the containers. At least one screen device, through which the charge carriers pass, is preferably arranged inside the housing. The electrons or the electron beam are thus preferably focused on this aperture device.

Within the housing, two sub-chambers of the housing preferably adjoin the orifice device, with a lower gas pressure prevailing within the sub-space closer to the generating device than within the sub-space further from the generating device. This means that a vacuum, which preferably decreases stepwise in the direction of the exit of the electrons, is also provided within the housing.

In a further advantageous embodiment, the sterilization device has a focusing device which focuses a charge carrier bundle. As mentioned above, this focusing takes place in particular for a passage through the aperture or apertures mentioned. According to the invention, a plurality of said partial spaces are provided within the housing, with a vacuum decreasing within these partial spaces, starting from the generating device towards the outlet opening.

In a further advantageous embodiment, an acceleration voltage of the acceleration device is less than 100 kV, preferably less than 80 kV and particularly preferably less than 60 kV. In this way, as mentioned above, costly shielding measures against X-rays can be dispensed with.

In a further advantageous embodiment, at least one control grid for controlling the output power of the charge carriers is provided inside the housing. In this embodiment, the beam current is not controlled via the emission of the cathode, but via a (almost inertia-free) control grid, which has a very short switching time (less than 1 ms), so that the container can also be positioned without overloading the bottleneck is easily possible.

The present invention is also directed to a system with a device of the type described above and a sterilization device of the type described above. This system preferably has a device for filling the containers with a liquid downstream of the sterilization device.

The present invention is also directed to a method for sterilizing containers, and in particular plastic containers, in which the containers are transported along a predetermined transport path through a treatment room and are sterilized within this treatment room using a sterilization device, with the sterilization device generating charge carriers and in particular electrons and Accelerated towards the containers. According to the invention, the charge carriers hit a wall of the containers and a path on which the charge carriers reach the container from a device for generating the charge carriers is free of material.

This material freedom can in turn reduce the necessary acceleration voltages for the charge carriers.

Preferably, a gas pressure inside the treatment space is kept below the gas pressure outside the treatment space.

• Darin zeigen:
  • 1 Eine schematische Darstellung einer Anlage zum Behandeln von Behältnissen;
  • 2 eine schematische Darstellung einer erfindungsgemäßen Sterilisationseinrichtung; und
  • 3 eine schematische Darstellung zur Veranschaulichung eines Reinigungsprozesses für Behältnisse.

Further advantages and embodiments result from the attached figures:

• Show in it:
  • 1 A schematic representation of a system for treating containers;
  • 2 a schematic representation of a sterilization device according to the invention; and
  • 3 a schematic representation to illustrate a cleaning process for containers.

1 shows a schematic representation of a system for treating containers. In this case, containers are fed to an indexing wheel 51 by means of a feed device, such as a transport chain 50 . This timing wheel 51 brings about a uniform division between the individual containers 10 and in turn feeds them to a transport device 6 . The transport device 6 here has a multiplicity of laterally extending projections 52, which each produce a seal with a wall of the system. The reference symbols P1-P3 refer to the transport path of the containers 10. The projections 52 form passage spaces with the wall of the system, within which the internal pressure drops continuously. For this purpose, several pumps 56a - 56d are provided, which continuously apply increasing vacuum to the interior up to a transport wheel 54 .

Reference number 8 refers to a treatment room in which the sterilization devices (not shown) are arranged. The pressure in the vicinity of the containers thus drops in the direction of arrow P1 and reaches its minimum in the area of the treatment chamber or arrow P2 and then increases again along arrow P3 up to atmospheric pressure.

In the embodiment shown here, the transport device 6 is followed by a shaping device 60 in order to shape preforms into containers. At the in 1 The representation shown is used to sterilize preforms in the area of the transport device 6 . Correspondingly, however, it would also be possible to sterilize already formed plastic containers and then to fill them. In this case, for example, a filling device could be connected to the transport device 6 .

With that, as in 1 shown, a plurality of locks is preferably provided, along which the pressure in the vicinity of the containers is continuously lowered. The entire arrangement can be arranged within a sterile room.

2 shows a schematic representation of a sterilization device 2 according to the invention. This sterilization device 2 initially has a generating device 4 for electrons, such as a tungsten cathode here. A current of electrons in the direction of an anode 24 can be controlled via a control grid 32, which may also act here as an acceleration device. The anode 24 itself has a bore 46 which serves as an aperture.

The reference symbol S refers to the beam path of the electrons or the electron beam. The generating device 4 and the acceleration device 24 are accommodated in a first space 16 within a housing marked 20 in its entirety. Within this first space 16 there is a pressure in the range of 10 ^-4 mbar. This space is delimited from a second space 34 by said anode hole, which acts as a screen.

This second space 34 has a pressure level in the range of 10 ^-3 bar. The reference number 22 refers to a focus lens, here configured electromagnetically, which causes the electron beam S to be focused again in the direction of a further aperture 26 . This additional panel 26 separates the second space 34 from a third space 36 . A pressure level in the range of 10 ^-2 mbar is provided in this third space 36 . The reference number 28 designates a further panel, which delimits the third space 36 from a fourth space 38 . Further focus coils 28 can be provided within this fourth space 38, which focus the electron beam S again.

The reference number 42 refers to an opening within the housing 20 through which the electrons can escape from the housing essentially unhindered. In the area of the aperture 28, a "crossover" of the electron beam occurs. In addition, however, further “crossovers” could also be provided.

3 12 shows a schematic representation to illustrate a sterilization process within the container 10. The reference symbol S again refers to the electron beam, which enters the interior of the container 10 through an orifice. The reference numeral 14 refers to a further focusing coil, with the help of which the entry of the electron beam S into the interior of the bottle 10 is facilitated. The reference number 12 refers to deflection devices (in particular in the form of coils) which guide the electron beam to desired areas of the inner wall 10a of the container.

It is thus also proposed here that the electron beam is completely, in particular over the use of pressure stages in air is brought out. It should be noted that, especially at low pressures of 0.1 mbar and less, the electrons are scattered so little that if a surface is to be irradiated, this is only possible through electromagnetic deflection. The focusing device 14 makes it possible to enlarge the beam spot in order to reduce the power density in the beam spot. The deflection device 12 causes the electron beam to be deflected so that every mm ² of the inner surface 10a of the container can be traversed so that the corresponding dose is distributed on the inner surface 10a.

To put it more precisely, the primary electron beam S is defocused here and then moved with the deflection coil 12 and a high frequency in a circular movement over the bottom 10c and the inner wall 10a. A neck area 10d of the container can preferably be reached by scattering the electron beam, which in turn, as mentioned above, depends sensitively on the process pressure.

Another possibility would be that the focusing coil 14 allows the electron beam to "breathe" quickly, in other words that the beam diameter of the electron beam is changed at high frequency and in this way the irradiation of the inner wall in an up and down movement is increased or decreased. reduction of the beam spot takes place.

In this case, this movement preferably does not take place linearly, but rather in accordance with the dose distribution. However, both of the movements mentioned could also be combined. With this procedure, it would be possible to work with low acceleration voltages, for example in the range of 30-60 kV.

At the in 3 In the representation shown, no rotational movement of the container, ie the PET preform or the bottle, is necessary, but merely a simple lifting, for example, in order to transport the container into the area of the two coils 14 and 12 . However, since the individual parameters are not linear and also depend on the current air pressure, sensitive sensor devices are preferably provided inside the treatment room in order to determine the air pressure exactly. Furthermore, a control device is also preferably provided which is able to control the coils 12 quickly and with a high clock rate.

However, it would also be possible for the container 10 to rotate and for the inner wall to be scanned here only in the longitudinal direction of the container, i.e. from bottom to top. Furthermore, it would be possible for a nitrogen or argon or generally noble gas atmosphere to be created in the treatment chamber 8 in order to avoid oxidation inside the sterilization device (due to the presence of oxygen). Thus, in addition to the generating device and the acceleration device, the sterilization device preferably has an electron bombardment gun, one or two focusing units, as well as an X,Y adjustment unit and an X,Y deflection unit.

Furthermore, as is known from the prior art, a high-voltage device with cathode heating is advantageously provided, with beam current control also being able to be integrated. In addition, the device advantageously has at least one turbo-vacuum pump and, in addition, additional large backing pumps and particularly advantageously also a rapid CNC control in order to carry out a scanning process inside the inner surface 10a of the container as quickly as possible.

A corresponding device preferably has a number of such sterilization devices in order in this way to increase the throughput of the containers to be sterilized.

All features disclosed in the application documents are claimed to be essential to the invention, provided they are new compared to the prior art, either individually or in combination.

Reference List

2

sterilization facility

4

generating facility

6

transport device

8th

treatment room

10

container

10a

inner wall of the container

10c

bottom of the container

10d

neck area of the container

12

deflection device

14

focus coil

16

first room

20

Housing

22

electromagnetically designed focus lens

24

anode

26.28

cover

32

control grid

34

second room

36

third room

38

fourth room

42

opening

46

Anode hole 24

48

focus coil

50

transport chain

51

clock wheel

52

protrusions

54

transport wheel

56a-56d

pump

60

forming device

P1-P3

arrows, transport path

S

Beam path of the electrons

Claims (14)

Device for sterilizing containers (10), with a transport device which transports the containers (10) along a predetermined transport path (P1, P2, P3) and a treatment room (8) in which the containers (10) are sterilized, wherein the transport device (6) transports the containers (10) through this treatment chamber (8), with at least one sterilization device (2) for sterilizing a wall of the containers, with this sterilization device (2) having a generating device (4) for generating charge carriers and a Accelerating device (24) for accelerating the charge carriers generated by the generating device (2) in the direction of the containers (10) located in the treatment space (8), a gas pressure inside the treatment space (8) being below a gas pressure outside the treatment space (8) located, characterized in that along the transport path (P1, P2, P3) of the containers (10) implementation gsraume are arranged, with a vacuum in the individual passage rooms towards the actual treatment room (8) increases successively. device after claim 1 , characterized in that the gas pressure within the treatment chamber (8) is below 800 mbar, preferably below 500 mbar, particularly preferably below 300 mbar and particularly preferably below 200 mbar. Device according to at least one of the preceding claims, characterized in that the device has deflection elements (12) for deflecting the charge carriers. device after claim 3 , characterized in that the deflection elements (12) have electrically operated deflection elements and in particular coils. device after claim 3 , characterized in that the deflection elements are arranged below a mouth of the containers (10) to be sterilized. Device according to at least one of the preceding claims, characterized in that passage spaces through which the containers (10) are passed are arranged along the transport path, the gas pressure within these passage spaces decreasing in the transport direction towards the treatment space. Sterilization device (2) for sterilizing containers (10) with a generating device (4) for generating charge carriers and an acceleration device (24) in order to propel the charge carriers generated by the generating device (4) in the direction of containers ( 10), and with a housing (20) in which the generating device (4) and the acceleration device are arranged, with a vacuum being present within this housing and with an opening through which the charge carriers emerge from the housing (20), thereby characterized in that a radiation path on which the charge carriers reach the container from the generating device (4) is free of material, with several sub-spaces being provided within the housing (20), with a vacuum within these sub-spaces starting from the generating device (4). to the exit opening decreases. Sterilization device (2) after claim 7 , characterized in that inside the housing (20) at least one screen device (26) is arranged, through which the charge carriers pass. Sterilization device (2) after claim 8 , characterized in that two sub-chambers (34, 36) of the housing adjoin the screen device (26), with a lower gas pressure prevailing within the sub-chamber (34) closer to the generating device (4) than within the one further from the generating device (4 ) located subspace (36). Sterilization device according to at least one of the preceding ones Claims 7 - 9 , characterized in that the sterilization device has a focusing device (22) which focuses a charge carrier bundle. Sterilization device according to at least one of the preceding ones Claims 7 - 10 , characterized in that an acceleration voltage of the acceleration device (24) is less than 100 kV, preferably less than 80 kV, and preferably less than 60 kV. Sterilization device according to at least one of the preceding ones Claims 7 - 11 , characterized in that at least one control grid (32) for controlling the output power of the charge carriers is provided inside the housing. Method for sterilizing containers (10), the containers (10) being transported along a predetermined transport path (P1, P2, P3) through a treatment room (8) and being sterilized within this treatment room (8) with a sterilization device (2), wherein the sterilization device (2) generates charge carriers and accelerates them in the direction of the containers (10), characterized in that the charge carriers hit a wall of the containers (10) and a path on which the charge carriers from a generating device (4) for the charge carriers reach the container (10), is free of material, passage spaces being arranged along the transport path (P1, P2, P3) of the containers (10), a vacuum in the individual passage spaces gradually increasing towards the actual treatment space (8). procedure after Claim 13 , characterized in that a gas pressure inside the treatment space (8) is kept below the gas pressure outside the treatment space (8).

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