Abstract:
The invention relates to a facility ( 1 ) for sterilizing objects by electron bombardment, this facility comprising a first conveyor ( 6 ) and a second conveyor ( 30 ) which are used for transporting objects ( 2 ) and placed on either side of a treatment chamber ( 14 ). According to the invention, the facility is provided with an input rotatable conveyor ( 8 ) designed for moving said objects and located between the first conveyor and the chamber ( 14 ), and an output rotatable conveyor ( 24 ) also designed for displacing objects and located between said chamber ( 14 ) and the second conveyor.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates in general to the field of sterilizing objects by electron bombardment, this bombardment possibly being of the low-energy type for treatment of the outer surface of these objects, or of the type having more significant energy in order to treat the core of these objects. 
         [0002]    It is particularly but not exclusively applicable to sterilization by electron bombardment of objects having a substantially rectangular parallelepiped shape, such as objects called “tubs” corresponding to closed containers holding a multitude of elements that have preferably been chemically pre-sterilized, such as medical syringes, for example. 
       STATE OF THE PRIOR ART 
       [0003]    Facilities enabling sterilization of objects having substantially rectangular parallelepiped shapes by low-energy electron bombardment, i.e. with an energy lower than approximately 400 keV, are known from the prior art. 
         [0004]    To do this, these facilities typically comprise three low-energy accelerator/gun-type sources of approximately 200 keV, and are arranged at 120° from each other around a treatment chamber through which the objects are moved translationally in order to be treated. In this way, during its continuous passage through the treatment chamber, the outer surface of each object is simultaneously illuminated over 360° by the combination of the three electron beams respectively coming from the aforementioned sources, which have been carefully positioned. 
         [0005]    This type of facility has proved to be satisfactory, particularly due to its effectiveness related to the slight penetration of the electron beam and the sporicidal effect produced, and also due to the rapidity of treatment as well as the safety provided. 
         [0006]    Nevertheless, this facility has a non-negligible drawback residing in the fact that it has a treatment chamber, within which the path of the object is relatively complex, for example U-shaped, so as to provide biological protection against to the electron beams emitted by the various sources of the sterilization means. Indeed, in such a case where the treatment chamber is defined by two stainless steel walls located on both sides of the path and each extending all along the U, the sterilization means are found at the base of the U, while the branches of this U are intended to be long enough to ensure that the radiations do not propagate beyond the open ends of these two branches through which the objects are intended to pass. On this account, it may be noted that the two open ends of the U may be likened to the inlet and outlet of the treatment chamber, on either side of which are found a first conveyor used to bring objects into this chamber, as well as a second conveyor, respectively, ensuring the removal of the treated objects toward a production isolator. 
         [0007]    Thus, the complex shape of the treatment chamber and the path of the object imposed by biological safety measures makes the bulkiness of the facility particularly substantial, such that it is therefore not entirely optimized. Moreover, it is consequently necessary to provide curved conveyors in the treatment chamber, the complexity and cost of which are greatly increased relative to traditional rectilinear conveyors 
       OBJECT OF THE INVENTION 
       [0008]    The object of the invention is therefore to propose a facility for sterilizing objects by electron bombardment at least partially resolving the abovementioned drawbacks relative to the prior art. 
         [0009]    To do this, the invention relates to a facility for sterilizing objects by electron bombardment, comprising sterilizing means able to generate at least one electron beam along an axis passing through a treatment chamber of the facility within which the objects are intended to be set into motion, the facility comprising a first conveyor as well as a second conveyor designed for moving objects and placed on either side of the treatment chamber. According to the invention, the facility is provided with an input rotatable conveyor used for transporting objects and placed between the first conveyor and the treatment chamber, and an output rotatable conveyor also used for transporting objects and placed between this treatment chamber and the second conveyor, the aforementioned rotatable conveyors being used and placed so as to provide a barrier for the radiations emitted by the sterilization means. 
         [0010]    It may be understood that one particularity of the invention resides in the fact of providing two rotatable conveyors intended to be set into rotation in order to transport objects, and respectively provided upstream from the inlet of the treatment chamber, and downstream from the outlet of this chamber. This therefore provides a barrier for the radiations emitted by the source(s) of the sterilization means, such that the treatment chamber no longer has to be made according to a complex shape such as those encountered in achievements of the prior art. 
         [0011]    The facility for sterilizing objects may therefore advantageously have reduced bulk, for example by providing a rectilinear path for the object inside the treatment chamber, while providing satisfactory biological protection against the electron beam(s) emitted by the various sources of the sterilization means. 
         [0012]    Preferably, each rotatable conveyor has multiple radial projections arranged such that any two of them, directly consecutive to each other, define a housing to receive an object, this object being able to be moved in the housing when the conveyor is set into motion, causing rotation of this housing. It is essentially these radial projections, for example four in number, which provide a biological protection barrier against the electron beam(s), both at the inlet and outlet of the treatment chamber. 
         [0013]    Preferably, the facility comprises a first transfer means making it possible to transport an object located at a downstream end of the first conveyor, into a housing of the input rotatable conveyor laid out facing this downstream end of the first conveyor. Thus, once the object is located inside the aforementioned housing, the input conveyor may be set into rotation so as to move this object into a position enabling it to be introduced in the treatment chamber. 
         [0014]    In this respect, it is noted that the facility comprises second transfer means making it possible to transport an object located in a housing of the input rotatable conveyor which communicates with an inlet of the treatment chamber, right up to the inside of this treatment chamber. Naturally, this housing which communicates with the inlet of the treatment chamber and in which is located an object to be treated corresponds to the same housing which was previously, before rotation of the input conveyor, laid out facing the downstream end of the first conveyor in order to receive the object coming from it. 
         [0015]    Moreover, the facility comprises a third transfer means making it possible to move an object located inside the transfer chamber, into a housing of the output rotatable conveyor which communicates with an outlet of this treatment chamber. Consequently, once the object is located inside the housing just mentioned, the output rotatable conveyor may be set into rotation in order to move this object such that it is entirely extracted from the treatment chamber. 
         [0016]    In this respect, it is noted that the facility comprises a fourth transfer means making it possible to move an object located in a housing of the output rotatable conveyor laid out facing an upstream end of the second conveyor, right up onto this upstream end of the second conveyor. Here again, it should be understood that the housing laid out facing the upstream end of the second conveyor corresponds to the same housing, which, before rotation of the output conveyor, was in communication with the outlet of the treatment chamber. 
         [0017]    The treatment chamber is equipped with at least one internal conveyor making it possible to set the objects into motion inside this chamber, and preferably equipped with a primary internal conveyor onto which the objects may be brought by the second transfer means, and with a secondary internal conveyor from which the objects may be moved into a housing of the output rotatable conveyor, by the third transfer means. 
         [0018]    In this configuration, which is particularly well-suited to cases where a plurality of sources each emitting an electron beam are implemented, it may be provided for the primary internal conveyor to have an upstream end located in proximity to the inlet of the treatment chamber, and for the secondary internal conveyor to have a downstream end located in proximity to the outlet of the treatment chamber. 
         [0019]    Moreover, it is also provided for the downstream end of the primary internal conveyor to be located facing and away from an upstream end of the secondary internal conveyor, so as to form an inter-conveyor space able to be crossed by the electron beams of the sterilization means. 
         [0020]    Preferably, the first conveyor, second conveyor, primary internal conveyor and secondary internal conveyor are each substantially rectilinear, and substantially arranged along a same straight line parallel to a direction of the forward motion of the objects. Thus, the object path inside the treatment chamber is rectilinear, which provides relatively small bulkiness. Moreover, although it was preferably provided to equally align the first and second conveyors placed on either side of this chamber, these may nevertheless be arranged differently, without departing from the scope of the invention. As an illustrative example, the first conveyor may be arranged at 90° relative to the primary internal conveyor, and likewise, the second conveyor may also be arranged at 90° relative to the secondary internal conveyor. This ability to modify the positioning of the first and second conveyors is naturally achieved by the presence of input and output rotatable conveyors, for which it is only necessary to modify the range of the rotations to be able to adapt to the various layouts of the conveyors. 
         [0021]    As previously stated, the sterilization means comprise a plurality of sources each generating an electron beam along an axis passing through the treatment chamber, and preferably three sources respectively generating three electron beams along axes arranged respectively at 120° relatively to each other, in a plane P orthogonal to a direction of forward motion of the objects. 
         [0022]    In this preferred solution which is particularly adapted to providing “surface” treatment, sterilization consists of achieving low-energy electron bombardment on the surface of the objects. Thus, as it continuously passes through the treatment chamber, at the inter-conveyor space, the outer surface of each object is simultaneously illuminated over 360° by the combination of the three electron beams respectively resulting from the aforementioned sources, which have been carefully positioned. In this respect, it is obviously specified that this is possible by providing that the plane P crosses the inter-conveyor space. 
         [0023]    Also preferentially, the sources are laid out such that each of the three axes passes through an object to be treated placed at this inter-conveyor space. 
         [0024]    Naturally, this solution with three sources or more may also be considered to provide a “core” treatment, according to which sterilization consists of achieving a stronger energy electron bombardment on the objects, the power then being able to be greater than 400 keV, and reaching 5 or even 10 MeV. Naturally, for the core treatment, the number of sources may be decreased or increased as needed, and is therefore not limited to three. 
         [0025]    The present invention also covers a facility whereof the sterilization means would be solely made up of only one source able to generate a single electron beam. This solution is recommended in the framework of a core treatment of the objects, and advantageously does not require providing for several internal conveyors within the treatment chamber. 
         [0026]    Preferably, the second conveyor opens into a production isolator into which the sterilized objects are transported. 
         [0027]    It is noted that with the invention it is also possible to perform a core treatment of objects packaged in their final packaging. In this type of case, the second conveyor opens into a production isolator, or into another protected environment, as the packaging itself protects the product after treatment. 
         [0028]    Preferably, the input rotatable conveyor is placed in a crown having an opening facing the first conveyor so that it may allow the introduction of objects into the input rotatable conveyor, and an opening located in the extension of the inlet of the treatment chamber and upstream therefrom. Similarly, the output rotatable conveyor is placed in a crown having an opening located in the extension of the outlet of the treatment chamber and downstream therefrom, and an opening located facing the second conveyor so as to allow extraction of the objects from the output rotatable conveyor. 
         [0029]    It is noted that these two crowns are each simultaneously used for providing a barrier against the radiations emitted by the beams, and for avoiding removal of the objects located in the housings of the rotatable conveyors, when the latter are set into rotation. 
         [0030]    Lastly, as stated above, it should be noted that the facility is made so as to allow surface or core treatment of the objects to be treated. 
         [0031]    Other advantages and characteristics of the invention will appear in the detailed and non-limiting description below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]    This description will be made with regard to the appended drawings, wherein: 
           [0033]      FIG. 1  shows a front view of a facility for sterilizing objects by electron bombardment, according to a preferred embodiment of the present invention; 
           [0034]      FIG. 2  shows a partial perspective view of the facility shown in  FIG. 1 , the objects to be treated having been voluntarily omitted from the illustration for reasons of clarity; 
           [0035]      FIG. 3  shows a diagrammatic top view of the facility shown in  FIGS. 1 and 2 , intended to show the path of the objects within this facility; 
           [0036]      FIG. 4  shows a diagrammatic front view of the facility shown in  FIGS. 1 and 2 , intended to show the various means of moving the objects present within this facility; and 
           [0037]      FIG. 5  shows a partial cross-sectional view along the V-V line of  FIG. 1 , intended to more specifically show the sterilization means of the facility. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0038]    With reference first to both  FIGS. 1 and 2 , a facility  1  for sterilizing objects  2  by electron bombardment may be seen, this facility  1  being preferably but not exclusively intended for the treatment of objects having a substantially rectangular parallelepiped shape. Moreover, even though the application described hereafter concerns the surface treatment of the objects to be sterilized, it may naturally be applied for core treatment of the latter. 
         [0039]    As previously stated, this object shape corresponds in particular to that of tubs holding a multitude of elements that have preferably been chemically pre-sterilized, such as medical syringes, for example one hundred of them per tub. 
         [0040]    The facility  1  rests on a floor  4 , which may be likened to a horizontal plane. On this account, it may be noted that the description will be made with reference to a direction X parallel to the floor  4  and corresponding to a direction of forward motion of the objects within the facility, a direction Y corresponding to a transverse direction of the facility also parallel to the floor  4 , as well as a direction Z corresponding to a height direction which is orthogonal to this same floor  4 , the directions X, Y and Z being orthogonal to each other. 
         [0041]    Overall, the facility comprises the following elements: a first conveyor  6 , an input rotatable conveyor  8  placed in a crown  10 , a first object transfer means  12 , a treatment chamber  14  in which are located a primary internal conveyor  16  cooperating with a second object transfer means  18  as well as a secondary internal conveyor  20  cooperating with a third object transfer means  22 , an output rotatable conveyor  24  placed in a crown  26 , a fourth transfer means  28 , and a second conveyor  30  opening into a production isolator  32 . 
         [0042]    On the other hand, this facility  1  also comprises sterilization means  34  which will be described in detail later on, with reference to  FIG. 5 , and which have the particularity on the one hand of producing at least one electron beam within the treatment chamber  14 , and on the other hand of being enclosed in a shielded casing  36  as shown in  FIG. 1 . As an indication, the shielded casing  36  may be made of lead with a thickness of approximately 15 mm within the framework of low-energy treatment (approximately 200 keV), or approximately 600 mm within the framework of higher energy treatment (for example, of the order of 5 MeV). 
         [0043]    The facility  1  also has two pipes  38 ,  40  communicating with the treatment chamber  14  and being used for bringing in fresh air, and removing the ozone produced by the electron bombardment, respectively. 
         [0044]    On the other hand, cooling means  42  as well as a klystron  44  connected to the sterilization means  34  are also provided on the facility  1 . 
         [0045]    More particularly with reference to  FIG. 2 , a direction of forward motion of the objects  46  within the facility  1  is shown, which is parallel to the direction X. The four conveyors  6 ,  16 ,  20 ,  30  are preferably straight/rectilinear and aligned along this direction  46 , as clearly visible in this  FIG. 2 . 
         [0046]    The first conveyor  6  is a gravity roller conveyor (or of another suitable type) ensuring automatic displacement of the objects  2  to be treated, substantially along the direction X. It has a downstream end  6 a located above and facing an opening  50  formed in the crown  10  to allow the passage of the objects  2 , and allows the introduction of these objects into the input conveyor  8 . In this respect, for the same reason as for certain other elements of the facility  1  which will be described hereafter, this crown  10  is preferably and primarily made of lead essentially for the purpose of providing complete biological protection against the electron beams emitted by the sterilization means  34  during treatment. 
         [0047]    Inside this crown  10 , the input rotatable conveyor  8  is located which has a plurality of radial projections  52 , preferably four and primarily in lead, laid out such that any two of them directly consecutive to each other define a housing  54  to receive an object  2 . As this may be seen in  FIG. 2 , the projections  52  defining four regularly distributed housings  54  may have a shape making it possible to define, two by two, substantially parallelepiped housings  54 , having a shape which complements that of the objects  2 , or that of an assembly of objects within the framework of a core treatment. Thus, each object  2  may then be set into rotation in one of the housings  54  along an axis  56  corresponding to the axis of rotation of the rotatable conveyor  8 , when this same rotatable conveyor is moved rotationally. It is noted as an indication, that the vertical axis  56 , also corresponding to the axis of the crown  10 , the inner surface of said annulus  10  conforming with the shape of the free ends of the radial projections  52 , is preferably located in a vertical plane parallel to the direction  46  and fictitiously crossing the four aligned conveyors, preferably in their middle. 
         [0048]    At a downstream portion of the crown  10 , the latter has another opening  58  which is located in the extension of an inlet  60  of the treatment chamber  14  and upstream therefrom, this opening  58  being diametrically opposite to the opening  50 . 
         [0049]    The treatment chamber  14  is defined by two walls  62 ,  64  primarily in lead, which are oriented according to planes XZ and which jointly define the inlet  60  as well as the outlet  66  of this chamber. Between these two walls  62 ,  64  providing biological protection, are located the two internal conveyors  16 ,  20 , for which one upstream end  16   a  of the primary internal conveyor  16  is located in proximity to the inlet  60 , and one downstream end  20   a  of the secondary internal conveyor  20  is positioned in proximity to the outlet  66 . 
         [0050]    Moreover, the downstream end  16   b  of the conveyor  16  and the upstream end  20   b  of the conveyor  20  are located facing each other, and are separated by an inter-conveyor space  68 , the length of which along the X direction is set so as to be smaller than the length along this same direction of an object  2  to be treated placed on the internal conveyor  16 , such that the relevant object may automatically pass from one internal conveyor to the other. The effect sought is in reality to be able to obtain a continuous feed of an object  2  from one end to the other of the treatment chamber  14  and solely with the help of two internal conveyors  16 ,  20  at regulated speeds, while also providing the inter-conveyor space  68  to allow the electron beams to illuminate the outer surface of this object  2  simultaneously over 360° when it passes above this space  68 . 
         [0051]    In the extension of the outlet  66  defined by the two parallel walls  62 ,  64 , is located an opening  70  of the crown  26  in which the output rotatable conveyor  24  is located, the layout between the latter and the crown  26  made primarily of lead being substantially identical to the one described between the crown  10  and the input rotatable conveyor  8 . 
         [0052]    More specifically, the output rotatable conveyor  24  has a plurality of radial projections  72 , preferably four and primarily in lead, laid out such that any two of them which are directly consecutive to each other define a housing  74  to receive an object  2 . As this may be seen in  FIG. 2 , the projections  72  defining four regularly distributed housings  74  may have a shape which makes it possible to define, two by two, substantially parallelepiped housings  74 , having a shape which complements that of the objects  2 . In this way, each object  2  may then be set into rotation in one of the housings  74  along an axis  76  corresponding to the axis of rotation of the rotatable conveyor  24 , when this same rotatable conveyor is set into motion. It is noted as an indication that the vertical axis  76 , also corresponding to the axis of the crown  26 , the inner surface of this crown  26  conforming with the shape of the free ends of the radial projections  72 , is preferably located in the vertical plane fictitiously crossing the four aligned conveyors. 
         [0053]    At a downstream portion of the crown  24 , the latter has another opening  78  diametrically opposite to the opening  70 , allowing the passage of objects  2  through this crown  24 , and located upstream and facing an upstream end  30   a  of the second conveyor  30  bringing these objects  2  towards the production isolator  32 . This opening  78  is primarily used to allow extraction of the objects  2  out of the output rotatable conveyor  24 . 
         [0054]    The second conveyor  30  is also a gravity roller conveyor (or of another suitable type) ensuring automatic displacement of the objects  2  to be treated, substantially along the direction X. 
         [0055]    Referring now more specifically to  FIGS. 3 and 4 , the path of a given object  2  through the facility  1  will be described. 
         [0056]    First, the rotatable conveyor  8  is set into rotation around the axis  56  such that one of its housings  54  is placed facing the opening  50 . Then, the first transfer means  12  is controlled so as to move in the X direction, the object  2  located the farthest downstream on the first conveyor  6 , into the aforementioned housing  54 , while passing through the opening  50 . 
         [0057]    The input rotatable conveyor  8  then completes two quarters of a revolution before presenting this object  2  facing the other opening  58 . The second transfer means  18  is controlled so as to move, in the X direction, the object  2  into the inside of the processing chamber  14 , while passing through the opening  58  and the inlet  60 . It is understood that at each step of the rotatable conveyor  8 , one object  2  has entered while another object  2  has exited, so as to optimize the pace. 
         [0058]    Once this object has entered into this chamber  14 , displacement of the object  2  in the direction X is automatically provided first by the internal input conveyor  16 , and then by the internal output conveyor  20 , these two conveyors being at a regulated speed. In this respect, it is noted that it is when the object  2  passes above the inter-conveyor space  68 , i.e. when it simultaneously rests on the downstream end  16   b  and the upstream end  20   b  of the conveyors  16 ,  20 , that it undergoes the most intense treatment, since it is then illuminated over 360° by the three electron beams which will be described hereafter. 
         [0059]    Displacement of the object  2  on the regulated speed conveyor  20  is performed until this object  2  reaches the outlet  66 , where this object  2  is able to cooperate with the third transfer means  22  controlled so as to move it in the X direction, right up to the inside of a housing  74  of the output rotatable conveyor  24 , while passing through the outlet  66  and the opening  70  of the crown  26 . To do this, the rotatable conveyor  24  is first set into rotation around its axis  76  such that one of its housings  74  is placed facing the opening  70 . 
         [0060]    When the object  2  is located in the housing  74 , the output rotatable conveyor  24  then completes two quarters of a revolution before presenting this object  2  facing the other opening  78 . The fourth transfer means  28  is then controlled so as to displace, in the X direction, the object  2  until it reaches the upstream end  30   a  of the second conveyor  30 , while passing through the opening  78 . Here again, it is understood that at each step of the rotatable conveyor  24 , one object  2  has entered while another object  2  has exited, so as to optimize the pace. 
         [0061]    Lastly, the object  2  is then automatically moved in the X direction by gravity on the conveyor  30 , right up into the production isolator  32 . 
         [0062]    Naturally, as shown in  FIG. 3 , it is noted that the facility  1  is designed to be able to receive and hold several objects  2  simultaneously, implying that several of them are therefore laid out behind each other inside the treatment chamber  14 . Another consequence, of course, lies in the fact that in operation, at each quarter revolution (each step) of the input rotatable conveyor  8 , a new object  2  arrives facing the inlet  60  of the treatment chamber  14 , before penetrating therein via the second transfer means  18 . 
         [0063]    As an indication, the rotatable conveyors  8 ,  24  may be associated with traditional electric motors to set them into rotation, while the elements  12 ,  18 ,  22 ,  28  may each assume the form of a stainless steel carriage mounted on a screw or ball, and actuated by a traditional electric motor. On the other hand, the elements  16  and  20  may each assume the form of a stainless steel chain link conveyor belt, and actuated by a traditional electric motor. 
         [0064]    With reference now to  FIG. 5 , showing the sterilizing means  34  presented in a preferred embodiment particularly well-suited to surface treatment of objects  2 , it may be seen that the latter have three sources  80   a,    80   b,    80   c  each generating an electron beam along axes A 1 , A 2 , A 3  respectively. 
         [0065]    These axes are globally positioned at 120° relative to each other in a plane P shown in  FIG. 4  and corresponding to the line V-V in  FIG. 1 . This plane P is orthogonal to the direction of forward motion of the objects  46 , and crosses the inter-conveyor space  68  preferably in its middle. This is why the outer surface of an object  2  passing above this inter-conveyor space  68  is illuminated over 360°, through the combined action of the three sources  80   a,    80   b,    80   c,  the axes A 1 , A 2 , A 3  of which preferably each cross this object  2  moving above the space  68 . 
         [0066]    Of course, various modifications may be made by one skilled in the art to the facility  1  for sterilizing objects by electron bombardment which has just been described solely as a non-limiting example.