Abstract:
A filling apparatus of flexible containers with a dense fluid, such as cream, yoghurt, honey, fruit juice, medicines and similar comprises vacuum devices, gas supply devices, filling devices and a valve. The valve comprises a main body, an obturator, a needle and a needle operating mechanism able to move the needle in translation. The obturator duct is connected to the vacuum and gas supply devices, to remove any residues of fluid aspirated.

Description:
The present application claims priority from Italian Patent Application No. BS2009A000071, filed Apr. 15, 2009, which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus for filling flexible containers with a fluid, for example foodstuffs, such as cream, yoghurt, honey, fruit and vegetable juice and purées, medicines and similar. 
     2. Description of the Prior Art 
     It is well known how consumers today have an extremely varied choice of products available to them in fluid form, especially foodstuffs, contained in flexible containers, for example formed of two films of plastic materials facing each other. 
     Filling the containers with a fluid is an extremely important operation which must satisfy a number of requisites: the container must be filled with a preset and constant quantity of fluid, the filling procedure must be rapid (to save on production costs), fluid must not be wasted by pouring it outside the container, the outside of the container must not be soiled by the fluid, filling must be performed in an sterile environment and further requisites still. 
     In the sphere of container filling apparatus the filler valve which fills the container with fluid when it is engaged to it, is of crucial importance. 
     One embodiment of such a valve is illustrated in the document EP-A1-0894723. 
     Such valves perform three essential functions in succession: they enable creation of a vacuum in the flexible container, filling of the container with the fluid and, lastly, the supply of a quantity of inert gases, to act as an anti-oxidisation barrier. 
     SUMMARY OF THE INVENTION 
     The purpose of the present invention is to make a filling apparatus in which the valve has a simplified structure to reduce the risk of the accumulation of fluid in inaccessible areas and consequent formation of bacterial hotbeds. 
     Such purpose is achieved by a filling apparatus for flexible containers comprising:
         vacuum devices able to generate a vacuum by suction;   gas supply devices, able to supply a pressurised gas;   filling devices, able to supply a dense fluid;   a valve comprising:
 
a) a main tubular body having a main inner compartment, connected to the filling device, and a main duct able to engage a straw of the container;
 
b) an obturator sliding in the main body between a forward position in which it closes off communication between the main duct and the main compartment and a retracted position, in which it allows communication, in which the obturator has an inner obturator duct and an obturator hole;
 
c) a needle sliding in the obturator duct between a retracted, closed position in which it closes the obturator hole and a forward open position, in which the hole is open;
 
d) means of operating the needle able to move the needle in translation;
 
in which the obturator duct is connected to the vacuum devices and the gas supply devices, to remove any residues of fluid aspirated.
       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a section of a valve of a filling apparatus according to the present invention, in a vacuum and gas supply configuration; 
         FIG. 2  shows the valve in  FIG. 1 , in a filling configuration. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An apparatus for filling flexible containers, such as a container C comprising a straw T, and two walls W made of flexible film, joined to each other along the edge, between which the straw T is inserted, comprises a filling valve  1 . 
     The valve  1  comprises a main tubular body  2 , which extends mainly along a main axis X. 
     The main body  2  comprises an end wall  2   a , into which a main duct  4  opens, which comes out in a main compartment  6  inside the body  2 . 
     The main compartment  6  is placed in communication with fluid supply devices of the apparatus (not shown) by means of a fluid supply duct  8 , suitable for supplying the fluid to fill the container with. 
     During normal functioning, the straw T of the container C is inserted in the main duct  4  of the end wall  2   a.    
     The valve  1  comprises, in addition, an obturator  10  sliding in the main body  2  and having a tubular shape elongated along the main axis X. 
     According to a preferred embodiment, the obturator  10  is made from polymer material. 
     The end of the obturator facing towards the end wall  2   a  is tapered, as is the end wall  2   a  at the entrance of the main duct  4 , so that when the obturator is in contact with the end wall, it closes off communication between the main compartment  6  and the main duct  4 . 
     The obturator  10  consequently slides between a forward position, in which it closes off communication between the main compartment  6  and the main duct  4 , and a retracted position, in which it allows communication. 
     The valve  1  preferably comprises in addition, obturator security devices able to constantly act on the obturator to press it from the retracted position to the forward position when there is no air. 
     For example, the obturator security devices comprise a spring  12 . 
     Preferably, the spring  12  acts on the obturator  10  at the end opposite that facing the main duct  4 ; at the other end to that engaged with the obturator, the spring  12  abuts, for example, against an annular boss  14  which projects inwards from the main body  2 . 
     The obturator  10  is traversed internally, along the main axis X, by an obturator duct  15  which terminates, on the side facing the main duct  4 , in an obturator hole  15   a.    
     The valve  1  comprises, in addition, a needle  16 , positioned along the main axis X and sliding inside the obturator  10 . 
     The needle  16  projects from the obturator  10 , through the obturator hole  15   a , and has an enlarged head  18  shaped so as to close the obturator hole  15   a  when abutting with the obturator. 
     In particular, the head  18  is enlarged so as to be a bigger than the aperture of the straw T, so as not to fall inside the container. At the same time, the head  18  is smaller than the main duct  4 , so as to form a passage when inserted in it. 
     The needle  16  has, at least in the section inside the obturator  10 , a smaller diameter than the obturator duct  15 , so that the cavity can be traversed by a gas. 
     In particular, the valve  1  comprises an intake  20 , joined to the obturator  10 , which places the obturator duct  15  in communication with vacuum device  7  of the apparatus, able to generate negative pressure so as to aspirate the air contained in the container, and with gas supply device  9 , able to supply a pressurised gas. 
     The needle  16  therefore slides in the obturator  10  between a retracted, closed position, in which the head  18  closes the obturator hole  15   a , so that the obturator duct  15  does not communicate with the main compartment  6 , and a forward, open position. 
     The valve  1  comprises, in addition, means of operating the needle  16  able to move it from the open position to the closed position. 
     Preferably, the operating mechanism comprises a cylinder-piston group  30 ; the piston  32  of the cylinder-piston group is joined to the needle  16 , at the end opposite the enlarged head  18 , while the cylinder  34  of the cylinder-piston group is attached to the main body  2 , on the side opposite that of the end wall  2   a.    
     The valve  1  comprises, in addition, needle return mechanisms able to constantly act on the needle  16  so as to bring the enlarged head  18  in abutment against the obturator  10 , in other words towards the closed position of the needle. 
     Preferably, the needle return mechanisms comprise a spring  40  and a cup  42  attached to the needle; the spring  40  is compressed between the obturator  10  and the cup  42 . 
     During normal functioning of the machine, the container C is engaged with the valve  1 , and in particular the straw T is inserted in the main duct  4 . 
     In a first phase of the procedure, called the vacuum phase, the obturator is in the forward position and the needle is in the open, forward position (vacuum configuration,  FIG. 1 ). 
     As a result, the fluid supply duct  8  and the main compartment  6  are not in communication with the main duct  4 , while the obturator duct  15  is in communication with the main duct  4 . 
     To reach the vacuum configuration, the needle operating mechanism is activated in the sense that the piston  32  is brought into the forward position, overcoming the resistance of the needle return mechanism, and maintaining such position for the entire vacuum phase: the needle is therefore in the open, forward position. The obturator security devices rather push the obturator into the forward position, until it abuts against the end wall  2   a . The needle return mechanisms also act on the obturator, pushing it into the forward position. 
     The vacuum device  7  is activated so as to create a negative pressure which aspirates the air from the container C, through the intake  20 , the obturator duct  15 , the open obturator hole  15   a  and the main duct  4 . 
     In a subsequent phase of the procedure, called the filling phase, the obturator is in the retracted position and the needle is in the closed, retracted position (filling configuration,  FIG. 2 ). 
     As a result, the fluid supply duct  8  and the main compartment  6  are in communication with the main duct  4 , while the obturator duct  15  is not in communication with the main compartment  6  or with the main duct  4 . 
     To reach the filling configuration, the needle operating mechanism is activated in the sense that the piston  32  is brought into the retracted position: the needle is therefore in the closed, retracted position and the head  18  has also dragged the obturator to the retracted position, raising it from the end wall  2   a  and overcoming the resistance of the obturator security devices. 
     The fluid supply means are activated so as to supply the container with the fluid, through the fluid supply duct  8 , the main compartment  6  and the main duct  4 . 
     The fluid contained in the main compartment  6  does not have access to the obturator duct  15 , since it is closed off by the enlarged head. 
     When filling has been completed, in a further subsequent phase of the procedure called the gas supply phase, the obturator is in the forward position and the needle is in the forward, open position (gas supply configuration,  FIG. 1 ). 
     As a result, the fluid supply duct  8  and the main compartment  6  are not in communication with the main duct  4 , while the obturator duct  15  is in communication with the main duct  4 . 
     To reach the gas supply configuration, the needle operating mechanism is activated in the sense that the piston  32  is brought into the forward position, overcoming the resistance of the needle return mechanisms, and maintaining such position for the entire gas supply phase: the needle is therefore in the open, forward position. The obturator security devices rather press the obturator into the forward position, until it abuts with the end wall  2   a.    
     The gas supply device  9  is activated so as to supply pressurised gas, usually inert gases such as nitrogen, to the container C, through the intake  20 , the obturator duct  15 , the open obturator hole  15   a  and the main duct  4 . 
     Innovatively, the filling apparatus described above makes it possible to use a valve with a simplified structure, which limits the accumulation of fluid in inaccessible areas and thereby the formation of bacterial hotbeds. 
     Advantageously, the path of the pressurised gas towards the container coincides with the aspiration path, so that any residues of fluid along the path are removed by the flow of gas. 
     Advantageously, in addition, the container remains engaged in the same position during the vacuum, filling and gas supply phases; as a result the apparatus according to the invention avoids the use of devices to modify the position of the container. 
     According to a further advantageous aspect, the simplified structure makes it possible to reduce the number of seals and gaskets, increasing the reliability of the valve and making for longer servicing intervals. 
     In addition, the use of the polymer material for the obturator makes it possible to avoid the use of sealing bands.