WO2015124357A1

WO2015124357A1 - E-beam container sterilization apparatus

Info

Publication number: WO2015124357A1
Application number: PCT/EP2015/051074
Authority: WO
Inventors: Roger Lindgren; Håkan MELLBIN
Original assignee: Tetra Laval Holdings and Finance SA
Current assignee: Tetra Laval Holdings and Finance SA
Priority date: 2014-02-19
Filing date: 2015-01-21
Publication date: 2015-08-27
Anticipated expiration: 2016-08-19

Abstract

The invention relates to an apparatus for sterilizing packaging containers (2). It comprises at least one sterilization device (50) preferably for sterilizing an interior of a packaging container (2) by electron beam irradiation. It further comprises a carousel (20), wherein the carousel (20) comprises a rotatable mounting plate (22) for supporting the at least one sterilization device (50). The at least one sterilization device (50) comprises an electron beam emitter (52) and a power device (66) for generating electrical power to be supplied to the electron beam emitter (52). The electron beam emitter (52) extends at least partly on a first side (23) of the rotatable mounting plate (22), and the power device (66) extends at least partly on a second side (24) of the rotatable mounting plate (22) opposite the first side (23). The rotatable mounting plate (22) has a radiation shielding (30), in particular for providing a radiation protection of the power device (66).

Description

E-BEAM CONTAINER STERILIZATION APPARATUS

The invention relates to an apparatus for sterilizing packaging containers.

In the food industry it is common practice to pack liquid and partly liquid food products in packaging containers. Such packaging containers can for example be made of a plastic material such as for instance PET, or be made of a laminated carton material. With regard to the later a common type of laminated carton material is the ones that comprises a core layer of paper or paperboard and one or more barrier layers of, for example, polymer material or aluminium foil. An increasingly common packaging type is the "carton bottle" manufactured in a filling machine in that packaging blanks of the above-described packaging laminate are formed and sealed as a sleeve. Said sleeve is closed in one end in that a top of thermoplastic material is injection moulded directly on the sleeve end portion. The sheets of packaging laminate may be cut from a magazine reel of packaging laminate.

Before the packaging container is filled with the food product, in particular if filling takes place at ambient temperature, the packaging container needs to be sterilized. Sterilization is a term referring to any process that eliminates or kills microbial life, including transmissible agents such as for example fungi, bacteria, viruses and spores, which may be present on a surface of the packaging material or in a product. In the (food) packaging industry this is generally referred to as aseptic packaging, i. e. packaging sterilized products in sterilized packaging containers, i. e. keeping both the product and the packaging container free form living germs and microorganisms, so that the freshness of the product can be preserved without special cooling requirements, i. e. so that sterility can be maintained inside a packaging container although it is stored in ambient temperature. In this context the term "commercially sterile" is also commonly used and means in general the absence of microorganisms capable of growing in the food at normal non- refrigerated conditions at which the food is likely to be held during manufacture, distribution and storage. In this patent application the word "sterile" refers to a condition being at least commercially sterile.

A conventional way of sterilizing packaging containers is a chemical sterilization, in particular using hydrogen peroxide, preferably in gas phase. However, this process has the drawback that residues of the chemical substance might remain on a surface of the container.

Another known way of sterilizing packaging containers is through radiation, in par- ticular, using electron beams. EP 2 371 397 A1 describes a sterilization machine comprising a plurality of sterilization devices adapted to be inserted into the containers for sterilizing the interior of the containers. In order to sterilize a container, the container is lifted relative to a corresponding sterilization device so that a rod- shaped sterilization element is inserted into the container for sterilizing the interior or the container. Another example of a sterilization device for sterilization of packaging containers is described in the international application No.

PCT/EP2013/076870 filed by the applicant.

Electron beam emitters produce cause emissions, in particular X-rays, and it is known in the art to have a protective system to protect the operators of such machines. The protection of the operator is generally achieved by shielding the operator form the rays, i.e. by placing the machine in a protective housing.

There is still a need to provide an apparatus for sterilizing packaging containers in a particularly safe and economical manner.

Henceforth, according to the invention an apparatus according to claim 1 and an apparatus according to claim 12 is proposed. Embodiments and several aspects of the invention are given in the dependent claims and the following description, in particular taken together with the attached drawings.

The invention will now be described further in connection with the attached drawings, in which: Figure 1 : shows a first aspect of an inventive sterilization machine;

Figure 2: shows an electron emitter to be used in connection with the first as- pect; and

Figure 3: shows a second aspect of an inventive sterilization machine.

Equal or corresponding elements are denominated with the same reference nu- merals in all figures. Features described in connection with any of the figures can be combined as long as technically possible.

According to a first aspect, the apparatus according to the invention for sterilizing packaging containers comprises at least one sterilization device preferably for sterilizing the interior surface of a packaging container by electron beam irradiation and a carousel. The carousel comprises a movable mounting plate for supporting the at least one sterilization device. The sterilization device comprises an electron beam emitter and a power device, in particular a high voltage power device, for generating electrical power to be supplied to the electron beam emitter.

The electron beam emitter is arranged at least partly on a first side of the movable mounting plate and the power device is arranged at least partly on a second side of the movable mounting plate. The second side is opposite the first side. The movable mounting plate comprises a radiation shielding, in particular for providing a radiation protection of the power device.

According to a second aspect, the apparatus according to the invention for sterilizing packaging containers comprises at least one sterilization device for sterilizing an interior surface of a packaging container by electron beam irradiation, and a carousel, wherein the carousel includes a movable support plate for transporting and/or guiding the packaging containers along a path where the packaging containers are adapted to be sterilized by the at least one sterilization device, and wherein the movable support plate is provided with a radiation shielding. The first aspect and the second aspect of the invention may also be combined.

The term carousel and movable mounting plate or movable support plate shall in- elude any type of movable device, for example conveyor chains or plates, belts, wheels and the like. The movement along a trajectory of the mounting plate or the support plate may comprise a pure translational or pure rotational movement or any combination thereof. In one embodiment, mounting plate or support plate may have the form of a wheel, in which a trajectory of each element of the plates is ba- sically a rotational movement. In another embodiment the carousel may comprise a conveyer element having a trajectory comprising translational and rotational portions.

In the foregoing and following, the term "packaging containers" are used as an example and for convenience. However, the invention is not limited to such packaging container. Generally any container, which needs to be sterilized, is suitable for this purpose and shall fall under this term, including, but not limited to, container for medical drugs, for medical devices, for liquid, semi-liquid or solid food, for storing biological material or organic substances.

The surface of the packaging container may comprise the inner surface of the packaging container, the interior and the outer surface or parts thereof of the packaging container. The inner surface of the container is the surface adapted to be in contact with the food or -more general-, with the material to be filled into the container. In an embodiment the at least one sterilization device is adapted to sterilize the inner surface of the container. In a further embodiment it is also adapted to sterilize part of the outer surface of the container.

In an aspect of the invention, the radiation shielding is adapted for protection against X-rays. In the following, the term X-ray includes all kinds of electromagnetic radiation and emissions generated during operation of the apparatus, including but not limited to electron collision radiation . These X-rays may be generated within the electron beam emitter and/or at the exit window of the electron beam emitter and/or outside the electron beam emitter. Generally, the X-rays may be generated when accelerated electrons are hitting a material.

An aspect of the invention is to provide a radiation shielding within the apparatus such that only a part of the rotating elements is arranged inside a shielded zone and another part of the rotating elements is arranged outside of the shielded zone. This selective shielding of only specific elements of the sterilization machine reduces the size of the shielded zone and therefore the cost of shielding. Another aspect of the invention is not only to protect an operator against undesirable rays generated by the electron beam emitter, but also to protect specified technical equipment against such rays. For example, electrical equipment such as a high voltage power device of the sterilization device and/or electric equipment of a conveyor or transport system for moving the packaging containers might be af- fected by a constant exposure to radiation . It is therefore desirable to place such equipment in a protected zone, outside a zone exposed to radiation.

Specifically, the invention according to the first aspect provides a radiation shielding for protecting the high voltage power device against X-rays. Preferably, the power device comprises an electrical power generator unit enclosed in a housing for generating a high voltage power, and the electron beam emitter comprises an electron exit window through which the electrons exit a vacuum chamber of the electron beam emitter. It is in this context advantageous that the electron exit window and the power generator unit are arranged on opposite sides of the radiation shielding of the mounting plate so as to protect the power generator unit from radiation generated at or near the electron exit window.

The rotatable mounting plate forms a protective barrier between an exposed area, in which radiation may be present, and a protected area that is substantially pro- tected from radiation. It is a basic concept of the invention to arrange the power device, in particular the electrical power unit, in the protected area, i.e. outside of the exposed area. This does not only provide a protection of the power device, but also increases serviceability. In addition to the power device other utility devices such as a cooling water supply may also be arranged in the protected area.

In an embodiment of the invention the electron beam emitter and the power device are mechanically, in particular directly, connected to each other. This means in particular that the electron beam emitter and the power device are directly contacting each other such that they form a single unit. In an alternative solution the housings of the electron beam emitter and the power device are connected to each other, in particular directly contacting each other. Such contact area can be within the area of the mounting plate.

One advantage of this embodiment is that the electrical connection between the power device and the electron beam emitter is confined within the single unit, thereby being reliably protected.

In an embodiment, the at least one sterilization device extends through the rotata- ble mounting plate. In such embodiment, the at least one sterilization device is separated by the rotatable mounting plate into a first portion extending from the mounting plate on a first side and into a second portion extending from the mount- ing plate on a second side of the mounting plate. The second portion may comprise elements of the at least one sterilization device to be protected from radiation being generated on the first side.

In such embodiment the electron beam emitter and/or the power device extends through the rotatable mounting plate. This can mean that the single unit comprising the electron beam emitter and the power device extends through the mounting plate. It can also mean that a part of the housing of the power device or a part of the housing of the electron beam emitter is arranged in a through-hole of the mounting plate. An interface between the electron beam emitter and the power device can be positioned on the first side of the mounting plate, on the second side of the mounting plate or in a plane defined by the mounting plate, i.e. within the through-hole. In order to reliably protect the components in the protected zone, in particular the power device, an embodiment of the invention comprises an interior radiation shielding provided within the sterilization device, in particular at an interface of the electron beam emitter and the power device and/or within the electron beam emit- ter and/or within the power device. The interior radiation shielding may be arranged between the power generator unit of the power device and an electron beam generator device such as a heatable filament for generating an electron beam. The interior radiation shielding, which extends at least partly along a cross- section of the sterilization device, may in particular be positioned within the sterili- zation device such that - when the sterilization device is positioned in a through- hole of the mounting plate - radiation is at least partly prevented from passing through the through-hole. In an embodiment, the interior radiation shielding within the sterilization device is provided essentially in the plane of the mounting plate, i.e. in the area of the through-hole. The interior radiation shielding can form an el- ement which delimits the vacuum chamber of the electron beam emitter. The interior radiation shielding may also support maintaining the vacuum in the electron beam emitter.

For providing a substantially uninterrupted radiation protection along the mounting plate including the through-holes, the interior radiation shielding is arranged in an aspect of the invention such that it contacts the radiation shielding of the rotatable mounting plate. To this end the interior radiation shielding extends at least partly along a cross-section of the sterilization device and including an outer surface of the sterilization device.

In another embodiment of the invention, the electron beam emitter comprises a holding plate for supporting an electron beam generator, in particular a cathode and/or a filament, and the holding plate forms at least a part of the interior radiation shielding. The holding plate may form a limitation of the vacuum chamber of the electron beam emitter and/or may support the electron beam generator within the vacuum chamber. The electron beam generator is preferably arranged on the first side of the rotatable mounting plate, i.e. on the opposite side of the power de- vice. In a preferred embodiment, the holding plate extends substantially across the entire cross-section of the electron beam emitter.

In another aspect of the invention, the rotatable mounting plate is arranged at an 5 opening of a stationary shielding element, in particular a shielding plate. Such arrangement provides a radiation protection also in an area surrounding the mounting plate. The rotatable mounting plate is arranged in the opening of the shielding element, in particular without contact. In an embodiment a small gap is formed between the stationary shielding element and the rotatable mounting plate for ali o lowing rotation of the mounting plate relative to the stationary shielding element.

The gap between the rotatable mounting plate and the stationary shielding element may be formed such that radiation is essentially prevented from passing through the gap. To this end, the gap is preferably formed such that no straight connection between the first side and the second side of the mounting plate is 15 present.

In another embodiment a shielding labyrinth is formed between the rotatable mounting plate and the stationary shielding element. The shielding labyrinth is preferably formed by a non-straight passage between the rotatable mounting plate

20 and the stationary shielding element. In an embodiment the stationary shielding element has at the periphery of its opening at least one shielding flange partially overlapping with the mounting plate in a radial direction. More preferably, a first shielding flange is radially overlapping on the first side of the mounting plate and a second shielding flange is radially overlapping on the second side of the mounting

25 plate.

The stationary shielding element comprises a radiation shielding, in particular against X-rays, similar to the radiation shielding of the rotatable mounting plate. Both may comprise the same materials. Preferably, the stationary shielding ele- 30 ment extends substantially in the same plane as the rotatable mounting plate.

In another embodiment a multi-stage radiation shielding is provided, in which at least two shielding devices are arranged in series. In this connection it is preferred that an additional radiation shielding element is provided which at least partly encloses the power device on the second side of the mounting plate, wherein the additional radiation shielding element is preferably arranged in series with the radiation shielding of the mounting plate. This additional radiation shielding element may in particular be arranged for protecting an operator against radiation, which - despite of the radiation shielding of the mounting plate - may be present on the second side of the mounting plate. The combination of the radiation shielding of the mounting plate and the additional shielding element provides a first level radiation shielding of the high-voltage power device and a second level radiation shield- ing of an operator, wherein the second level shielding is greater than the first level shielding. The additional radiation shielding element is preferably a stationary shielding element.

As a shielding material for all shieldings any suitable material generally known in the art may be used. Such materials generally have a high number of protons and/or electrons such as for example more than 50, more than 60, or more than 70. In an embodiment the radiation shielding may include any of the materials tungsten and/or lead including its alloys, for example tungsten carbide. Alternatively, it is generally possible to use a steel layer of an adequate thickness.

In a corresponding manner to the radiation shielding of the rotatable mounting plate, the radiation shielding of the rotatable support plate for supporting and/or guiding the packaging containers provides a radiation protection of components arranged on a side of the support plate opposite the at least one sterilization de- vice. The advantages and embodiments described in connection with the first aspect of the invention can therefore be transferred and applied correspondingly to the embodiments relating to the radiation shielding at the rotatable support plate (second aspect). In another aspect of the invention at least one lifting device for lifting the packaging container is provided, the at least one lifting device extending through the support plate, which can also be called a support wheel. The lifting device can include a lifting rod extending through the wheel or plate, wherein one end of the lifting rod is preferably attached to a holder for holding the packaging container such that by moving the lifting rod along an axial direction the packaging container is lifted.

In another embodiment the lifting device is connected to a drive unit for operating the lifting device, the drive unit arranged on a side of the support plate opposite the at least one sterilization device. The radiation shielding of the support plate therefore protects the drive unit against radiation, in particular X-rays.

In one or more embodiments the drive unit comprises any of the following: a linear motor, a servo motor, a pneumatic drive/motor or a mechanical drive such as for example a cam curve. Alternatively, also a standard (rotating) electric motor can be used, wherein a mechanism is provided that translates the rotation in a stroke move. In one or more embodiments a linear motor is used. Corresponding to the interior radiation shielding of the sterilization device, the at least one lifting device may include an interior radiation shielding so as to protect the elements on the side of the support plate opposite the at least one sterilization device against radiation passing through a through-hole of the support plate in which the lifting device is received. The description of the interior shielding in con- nection with the sterilization device can be applied and transferred to the interior shielding of the lifting device in a corresponding manner.

The inventive apparatus also includes any combinations of radiation shielding at the rotatable mounting plate and the rotatable support plate. One aspect of the invention can also be seen in an exposed zone in which radiation is present and which zone or area is delimited by the rotatable mounting plate and/or the rotatable support plate. The exposed zone, in which at least the exit window is located, is at least partly enclosed by a radiation protection, wherein the radiation protection comprises a radiation shielding at the rotatable mounting plate and/or the ro- tatable support plate. The exposed zone between the rotatable mounting plate and the rotatable support plate is delimited by a radiation shielding at the rotatable mounting plate and/or the rotatable support plate. Figure 1 shows a cross sectional view of a first embodiment of the invention. The inventive apparatus 10 comprises a first carousel 20 having a mounting plate 22, preferably a circular or polygonal plate, which is mounted in a rotating manner on a stationary frame (not shown). The first carousel 20 further comprises a drive shaft 28 for rotating the mounting plate 22, the drive shaft 28 being connected to the mounting plate 22 in a fixed manner. The drive shaft may be in turn connected to a motor for rotating the plate. Drive shaft 28 may be hollow and contain electrical connections, cooling systems or other elements configured to enable operation of apparatus 10 and elements thereof described further below. A vertical rotation axis 4 extends substantially through the centre of the mounting plate 22 and the drive shaft 28.

The rotary mounting plate 22 supports a plurality of sterilization devices 50, which are adapted to sterilize packaging container 2 by electron irradiation described further down in greater detail. The plurality of sterilization devices 50 is arranged on a circumference of the mounting plate 22. Each sterilization device 50 includes an electron beam emitter 52 for generating and emitting en electron beam and a power device 66 for generating high-voltage power which is to be supplied to the electron beam emitter 52.

The mounting plate 22 is provided with a radiation shielding 30. Mounting plate 22 comprises a shielding material such as for example tungsten or lead so that the material of the mounting plate 22 itself forms the radiation shielding 30. In this em- bodiment, mounting plate 22 comprises a layer structure with an inner layer (not shown) made of a very strong material providing the required stability to withstand rotational or other forces. The inner layer of plate 22 is then at least partly covered by shielding material thick enough to provide the required radiation shielding. Plate 22 may also comprise a hollow structure to save weight, while maintaining stability and radiation shielding capabilities. Radiation shielding 30 extends substantially along the entire surface of the mounting plate 22. Of course mounting plate 22 may have another structure, for instance made of an allow providing radiation shielding and stability. An embodiment of a sterilization device 50 will now be described with reference to figures 1 and 2. The sterilization devices 50 are substantially constructed in the same manner so that the following description also applies to the other sterilization devices 50 provided on the mounting plate 22.

The electron beam emitter 52 comprises a hermetically sealed vacuum chamber 54, an electron beam generator 56 arranged in the vacuum chamber 54 for generating an electron beam, and an electron exit window 58 at a longitudinal end of the vacuum chamber 54.

The vacuum chamber 54 has housing 60 having an elongate and in particular substantially cylindrical shape. Housing 60 comprises first housing part 62 having a smaller cross-section and a second housing part 64 having a larger cross- section than housing part 62. The electron beam generator 56 comprises a heatable filament and/or a cathode and is preferably arranged within the second housing part 64 of the housing 60. The rod-shaped, cylindrical first housing part 62 provides an electron acceleration zone between the electron beam generator 56 and the electron exit window 58 which is located at an end surface of the first housing part 62.

The electron beam is generated by heating the filament. When an electrical current is fed through the filament, the electrical resistance of the filament causes the filament to be heated to a temperature at which electrons are emitted by the fila- ment. This temperature may be in the order of 2000°C. The electrons are accelerated towards the electron exit window 58 by means of a voltage potential between the cathode and the electron exit window 58 which constitutes an anode. Subsequently, the electrons pass through the electron exit window 58 and continue towards a target area, i.e. in this case the inside of the packaging container 2.

In operation, a relative movement between emitter 52 with its second portion 62 and the container 2 to be sterilized is executed, resulting in a movement of portion 62 into the interior of container 2. For example container 2 is lifted toward portion 62 while emitting electron radiation. By this the inner surface of container 2 is sterilized all the way down to the far end of container 2, i.e. to the innermost area. Further the electron radiation forms an electron cloud close to exit window 58. Every surface part of container 2 passing through said cloud and remaining there for a certain period of time is sterilized. As such electron beam emitter 52 may not only be used to sterilize the inner surface an interior of container 2, but also a portion of the outer surface, particular close to the opening of container 2.

The period of time (sterilization time) a part of the surface of the container has to remain within the electron cloud generated by electron beam emitter 52 must be sufficiently high to eliminate all microbiological substances. In other words each part of the container to be sterilized must be exposed to a sufficiently high dosage. Such dosage (and the corresponding sterilization time) may depend inter alia from the speed of the movement between electron beam emitter 52 and packaging con- tainer 2, the electron voltage, the electron current, gas composition and density within and around the container, diameter or distance between of the beam emitter and container, shape of the container and the electron distribution through the exit window. The power device 66 comprises a housing 70 in which an electrical power generator unit 68 for generating high-voltage power is arranged. The electrical power generator unit 68 comprises at least one electronic device.

The housing 60 of the electron beam emitter 52 and the housing 70 of the power device 66 are directly connected to each other at a mechanical connecting interface 78, thereby forming a single unit of a sterilization device 50. In particular, the second housing part 64 of the electron beam emitters 52 is directly connected to the housing 70 of the power device 66. The connecting interface 78 may include an electrical interface for connecting the electron beam generator 56 within the electron beam emitter to the electrical power generator unit 68 within the power device 66. In the embodiment according to Figure 1 , the rotary mounting plate 22 separates the apparatus according to the invention basically into a lower portion below rotat- able mounting plate 22 and an upper portion above rotatable mounting plate 22. The sterilization device 50 is arranged in a through-hole 26 of the mounting plate 22 such that the electron beam emitter 52, in particular lower portion 62 and the electron exit window 58, is arranged on the first side 23 of the rotatable mounting plate 22 and the power device, in particular the power generator unit 68, is arranged on a second side 24 of the rotatable mounting plate 22 opposite the first side 23. More particular, parts of the electron beam emitter 52 extend from the first side into the lower portion of the apparatus, while power device 66 is arranged in the upper portion.

The connecting interface 78 between the housing 60 and the housing 70 is ar- ranged in the upper portion, i.e. on the second side 24 of rotatable mounting plate 22. Alternatively it may be arranged on the first side 23 or in the plane of the mounting plate 22, i.e. within the through-hole 26, as shown in figure 1 by the dashed lines. Each sterilization device 50 includes an interior radiation shielding element 76 extending within the sterilization device 50, and particular within the upper portion of electron beam emitter 52. By such the interior radiation shielding element 76 is arranged at a position of the sterilization device 50 within the through-hole 26 of the mounting plate 22, as shown in figure 1 . In this embodiment shielding element 76 is arranged below the connecting interface 78 to effectively shield electrical connections from radiation. Alternatively, the interior radiation shielding element 76 can be arranged within the housing 70 of the power device 66 or at the interface 78 between the electron beam emitter 52 and the power device 66. Interior radiation shielding element 76 comprises feed through for electrical connections to the electron beam generator 68 and/or the exit window 58

A more detailed embodiment of this aspect is illustrated in figure 2. The interior radiation shielding element 76 is formed by a holding plate 57 arranged within the electron beam emitter 52 for holding the electron beam generator unit 56, in particular for holding the heatable filament 57 and/or the cathode. When placing emitter 52 of figure 2 in the apparatus of figure 1 , radiation shielding element 76 may be arranged close to the first side 23 of mounting plate 22, such that electron beam generator is arranged in the lower portion of the apparatus below first side 23.

The mounting plate 22 is positioned in a preferably circular opening of a stationary shielding element 80, which may in particular be a shielding plate or a shielding ring. A gap 82 between the stationary shielding element 80 and the rotating mounting plate 22 is formed as a shielding labyrinth 84. To this end, the stationary shielding element 80 comprises a shielding flange 86 overlapping in the radial direction with the mounting plate 22. As illustrated in figure 1 , two shielding flanges 86, 88 may be present, one adjacent to the first side 23 and another adjacent to the second side 24 of the mounting plate 22.

For an additional radiation protection, an exterior radiation shielding element 90 is provided on the second side 24 of the mounting plate 22, thereby providing in particular a radiation protection for an operator against radiation present in the upper portion on the second side 24 of the mounting plate 22.

Figure 3 shows another embodiment of a sterilization apparatus according to the invention. The sterilization apparatus 10 comprises a carousel 40 having a rotata- ble support wheel or plate 42 for guiding and/or transporting packaging containers 2 along a circular transportation path such that each packaging container 2 can be aligned with a sterilization device 50 during its transportation along the transportation path.

Instead of a carousel 40, a conveyor chain or a similar device can be used for transporting packaging containers 2 along a predefined path and in alignment with sterilization device 50.

Support plate 42 supports a plurality of lifting devices 46 for lifting the packaging containers 2 to be sterilized in the direction of a sterilization device 50. Figure 3 shows two positions of such lifting devices, in which the container 2 is lifted and lowered, respectively.

The packaging containers 2 are arranged on a first side 41 a of the support plate 42 which in the shown embodiment is an upper side. The lifting devices 46 extend through through-holes 47 in the support plate 42. Each lifting device 46 is connected to a holder 48 for holding a packaging container 2. The carousel 40 further comprises a drive shaft 44 which is connected to the support plate 42 a fixed manner for rotating the support plate 42.

In this embodiment a linear servo motor 49 is provided for operating the lifting devices 46. The linear servo motor 49 is arranged on a second side 41 b of the support plate 42 opposite the first side 41 a, on which the packaging containers 2 are arranged.

The support plate 42 comprises a radiation shielding 43 against radiation, in particular X-rays. The support plate 42 may be constructed from a material such as lead or tungsten such that the support plate 42 itself provides the radiation shielding 43. It may also comprise a similar structure as described previously. However, depending on the radiation level to be shielded, the structure, dimensions or materials used can be different from each other.

In addition, the lifting device 46 may be equipped with an interior radiation shielding 45 extending at least partly along the cross-section of the lifting device, in par- ticular an axially movable lifting rod of the lifting device 46. Such interior radiation shielding 45 comprises at least two shielding elements arranged in the lifting rod with a certain distance to each other. The distance between two shielding elements is chosen such that there is always at least one shielding element between the lower side and upper side of the support plate 42 during the lifting process. In other words during the swing of lifting device 46 at least one shielding element is within the through-holes 47 in the support plate 42 effectively shielding from radiation. Alternatively, interior radiation shielding 45 may comprise only one shielding element. In such case the shielding element comprises a vertical dimension or thickness large enough to stay arranged at least partly within the through-holes 47 during the swing of lifting device 46. Alternatively, the lifting device 46 may itself constitute radiation shielding, i.e. it may be made of a radiation shielding material or may have such thickness that it forms a radiation shielding. A rod made of stain- less steel of an adequate thickness may in itself be radiation shielding enough.

In a particularly embodiment, the sterilization apparatus 10 comprises a first carousel 20 as shown in figure 1 and a second carousel 40 as shown in figure 3, wherein the first carousel 20 and the second carousel 40 are coaxial with each other and rotatable about the common rotation axis 4. As described earlier the invention is not limited to carousels. Any conveyor or similar element suitable for transporting electron beam emitter 50 and containers 2 along a predefined path are falling within the scope of the invention. An area, which is exposed to radiation, is formed between the mounting plate 22 and the support plate 42. The mounting plate 22 and the support plate 42 each are provided with radiation shielding 30 and 43, respectively. The shielding form a protective barrier of the exposed area such that the second side 24 of the mounting plate 22 and the second side 41 b of the support plate 42 are substantially pro- tected from radiation.

During a sterilization cycle, the first housing part 62 of the sterilization device 50 is inserted into the packaging container 2 through an opening thereof for sterilizing the inner surface and the interior of the packaging container 2. To this end, the lifting device 46 moves the packaging container 2 towards and away from the sterilization device 50 such that the sterilization device 50 is inserted into the packaging container 2 during the movement of the packaging container 2 together with the support plate 42. The support plate 42 is rotating synchronously with the mounting plate 22, such that each packaging container 2 is synchronously moved with a sterilization device 50, thereby keeping the longitudinal axis of the sterilization device 50 aligned with a longitudinal axis of the packaging container 2. The inventive sterilization machine provides in an economical way an effective radiation shielding against radiation in a sterilization machine, in particular X-rays.

The device according to the invention can be arranged in an irradiation chamber in a filling machine. The filling machine comprises at least one filling station for filling content into the packaging container and at least one station for sealing the opening after filling. The invention can for example be applied in the sterilization device as described in the international application No. PCT/EP2013/076870 filed by the applicant. During interior sterilization of the packaging containers a relative move- ment is made between the packaging container and the emitter. A plurality of emitters are provided on a carousel or the like which is adapted to rotate. The packaging containers, which are transported for example via a conveyor, reach the carousel and are attached to one of the (rotating) emitters. During at least a part of one rotation of the carousel, the sterilization of the interior surface of the packag- ing container takes place. Then the packaging container is removed from the appropriate emitter or from the carousel, respectively, and transported into an aseptic chamber for filling and sealing. The entrance of the aseptic chamber may include emitters for outside sterilization of the packaging containers.

Reference numerals:

2 packaging container

4 rotation axis

10 sterilization machine

20 carousel

22 mounting plate

23 first side

24 second side

26 through-hole

28 drive shaft

30 radiation shielding

40 carousel

41 a first side

41 b second side

42 support plate

43 radiation shielding

44 drive shaft

45 interior radiation shielding

46 lifting device

47 through-hole

48 holder

49 linear servo motor

50 sterilization device

52 electron beam emitter

53 housing

54 vacuum chamber

56 electron beam generator

57 holding plate

58 electron exit window

60 housing

62 first housing part

64 second housing part power device

power generator unit

housing

interior radiation shielding

interface

stationary shielding element gap

shielding labyrinth

shielding flange

additional radiation shielding element

Claims

1 . Apparatus for sterilizing packaging containers (2), the apparatus comprising at least one sterilization device (50) for sterilizing preferably a packaging container (2) by electron beam irradiation and

a carousel (20),

wherein the carousel (20) comprises a rotatable mounting plate (22) for supporting the at least one sterilization device (50),

wherein the at least one sterilization device (50) further comprises:

an electron beam emitter (52) and

a power device (66) for generating electrical power to be supplied to the electron beam emitter (52),

wherein the electron beam emitter (52) extends at least partly on a first side (23) of the rotatable mounting plate (22), and

wherein the power device (66) extends at least partly on a second side (24) of the rotatable mounting plate (22) opposite the first side (23), and wherein the rotatable mounting plate (22) comprises a radiation shielding (30), in particular for providing a radiation protection of the power device (66).

2. Apparatus according to claim 1 ,

wherein the electron beam emitter (52) and the power device (66) are mechanically, in particular directly, connected to each other.

3. Apparatus according to any of the preceding claims,

wherein the at least one sterilization device (50) extends through the rotatable mounting plate (22). 4. Apparatus according to any of the preceding claims,

wherein an interior radiation shielding (76) is provided within the at least one sterilization device (50), in particular at an interface between the elec- tron beam emitter (52) and the power device (66) and/or within the electron beam emitter (52) and/or within the power device (66).

Apparatus according to claim 4,

wherein the interior radiation shielding (76) is arranged such that it contacts the radiation shielding (30) of the rotatable mounting plate (22).

Apparatus according to claim 4,

wherein the electron beam emitter (52) comprises a holding plate (57) for supporting an electron beam generator (56), in particular a cathode and/or a filament, and

the holding plate (57) forms at least a part of the interior radiation shielding (76).

Apparatus according to any of the preceding claims,

wherein the rotatable mounting plate (22) is arranged at an opening of a stationary shielding element (80).

Apparatus according to claim 7,

wherein a gap (82) between the rotatable mounting plate (22) and the stationary shielding element (80) is formed such that radiation is essentially prevented from passing through the gap (82).

Apparatus according to claim 7 or 8,

wherein a shielding labyrinth (84) is formed between the rotatable mounting plate (22) and the stationary shielding element (80).

Apparatus according to any of the preceding claims,

wherein it further comprises an additional radiation shielding element (90), which at least partly encloses the power device (66) on the second side (24) of the mounting plate (22).

Apparatus according to any of the preceding claims, wherein the radiation shielding (30, 76, 90) comprises at least one of the following materials: tungsten, lead and steel.

12. Apparatus for sterilizing packaging containers (2), the apparatus comprising at least one sterilization device (50) for sterilizing an interior of a packaging container (2) by electron beam irradiation, and

a carousel (40),

wherein the carousel (40) comprises a rotatable support plate (42) for transporting and/or guiding the packaging containers (2) along a path where the packaging containers (2) are adapted to be sterilized by the at least one sterilization device (50),

wherein

the rotatable support plate (42) is provided with a radiation shielding (43). 13. Apparatus according to claim 12,

wherein at least one lifting device (46) for lifting the packaging container (2) is provided, the at least one lifting device (46) extending through the support plate(42). 14. Apparatus according to claim 13,

wherein the at least one lifting device (46) is connected to a drive unit for operating the lifting device (46), the drive unit being arranged on a side (41 b) of the support plate(42) opposite the at least one sterilization device (50).

15. Apparatus according to claim 13 or 14,

wherein the at least one lifting device (46) comprises an interior radiation shielding (45) or is at least partly made of radiation shielding material .