Abstract:
A filling element for filling containers includes a housing having a liquid channel, a connection for feeding liquid into the channel, a discharge port for discharging liquid into a container provided in a sealed position on the filling element, a valve in the channel between the connection and the port, an actuator for opening and closing the channel, a gas path for pre-stressing the container&#39;s interior with gas and returning displaced gas, a switching valve in the gas path, the valve being switchable by the actuator between a first state for use while pre-stressing and a second switched state for use with displaced gas, wherein in the first state, the gas path has a first effective flow cross section, and in the second state, the gas path has a second effective flow cross section, the second effective flow cross section being different from the first effective flow cross section.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is the national phase under 35 USC 371 of international application no. PCT/EP2011/001756, filed Apr. 8, 2011, which claims the benefit of the priority date of German application no. 10 2010 022 985.7, filed Jun. 8, 2010. The contents of the aforementioned applications are incorporated herein in their entirety. 
     FIELD OF DISCLOSURE 
     The invention relates to a filling element as well as to a filling machine. 
     BACKGROUND 
     Filling elements and filling machines for filling bottles or similar containers, in particular also for pressure-filling, are known in different embodiments. 
     For the purpose of the invention, the term “pressure-filling” is to be understood generally to mean a filling method wherein before the actual filling phase, i.e. before the opening of the liquid valve, the respective container that is to be filled and that lies with its container mouth in sealed position against the filling element is pre-stressed with a pressurised pressure gas (inert gas or CO2 gas) which the filling material flowing to the container then increasingly displaces as return gas from the container interior during filling. 
     For the purpose of the invention, “container in sealed position with the filling element” means that the respective container that is to be filled lies in the manner known to the skilled person with its container mouth pressed seal-tight against the filling element or against a seal at that location which encircles the at least one discharge port. 
     In the case of known filling elements, the pressure gas is delivered to the respective container and the return gas is taken away from the respective container over one and the same controlled gas path configured in the filling element, i.e. over a gas path in which a control valve is disposed. This is then for example part of a pneumatic control valve array and is controlled by at least one electrically controllable switching valve of a machine controller of the filling machine. 
     In order among other things to increase the output of a filling machine (number of filled containers per unit of time) while maintaining the gentle filling of the containers, it would make sense if the effective flow cross-section of the gas path for the pressure gas were greater than the effective flow cross-section of the gas path for the return gas, since on the one hand the time (cycle time) for pre-stressing can be reduced and on the other hand a filling speed that is optimum for gentle filling can be achieved in this way. For the purpose of the invention, “effective flow cross-section” means that flow cross-section which the respective gas path exhibits overall and which is essentially determined by the section (gas path section) of the gas path having the smallest cross-section. 
     This requirement for a larger effective flow cross-section for the pressure gas and at the same time for a reduced effective flow cross-section for the return gas cannot be satisfied by a single control valve in the common gas path for the pressure gas and the return gas. 
     Instead this would require at least two control valves with associated electrical switching valve, and this would mean a considerable complexity in terms of both design and in particular of circuit engineering and control engineering. 
     SUMMARY 
     The task of the invention is to provide a filling element which with little additional design complexity facilitates different flow cross-sections for the pressure gas and the return gas with no additional complexity in terms of circuit engineering and control engineering. 
     A peculiarity of the invention consists generally in the fact that in the common gas path—which may also be bifurcated for example—for the pressure gas and the return gas a switching valve is provided which in a first switched state brings about a first effective flow cross-section, for example the greater effective flow cross-section of the gas path for the pressure gas, and in a second switched state brings about a second, smaller than the first, effective flow cross-section of the gas path, for example for the return gas. The switching valve is switched by a drive or mechanically, preferably via a valve stem of the liquid valve or via a valve tube or gas tube, by the actuator of the liquid valve, and exhibits the first switched state for example when the liquid valve is closed and the second switched state for example when the liquid valve is open. The switching valve can be realised in a relatively simple way while retaining the proven design of the filling element. 
     Further embodiments, advantages and possible applications of the invention arise out of the following description of embodiments and out of the figures. All of the described and/or depicted attributes whether alone or in any desired combination are fundamentally the subject matter of the invention independently of their synopsis in the claims or a retroactive application thereof. The content of the claims is also made an integral part of the description. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The invention is explained in detail below through the use of embodiment examples with reference to the figures. In the figures: 
         FIG. 1  shows in simplified partial representation a filling system according to the invention, together with a bottle raised in sealed position against the filling element of this system; 
         FIGS. 2 and 3  each show in enlarged schematic partial representation a gas space and a switching valve there configured of the filling element of  FIG. 1  with two different versions of this valve; 
         FIG. 4  shows in simplified partial representation a filling system according to the invention, together with a bottle raised in sealed position against the filling element of this system in the case of a further embodiment of the invention; 
         FIG. 5  shows in enlarged schematic partial representation a gas space and a switching valve there configured of the filling element of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION 
     The filling system indicated generally in  FIG. 1  by  1  is part of a rotary-type filling machine for filling a liquid filling material into bottles  2  or similar containers. To this end, filling system  1  consists among other things of filling elements  3 , of which only one filling element  3  is shown in  FIG. 1  and which are provided at equal angular distances about the periphery of a rotor  4  of the filling machine which (rotor) can be driven to rotate about a vertical machine axis. On the only partially depicted rotor  4  is disposed a tank  5  common to all filling elements  3  and which is configured for example as an annular tank and which during the filling operation is partly filled with the filling material up to a predetermined level N by way of level control. During the filling operation therefore, tank  5  is occupied by an upper gas space  5 . 1  and a lower liquid space  5 . 2 . If filling system  1  is used for pressure-filling the liquid filling material into the containers or bottles  2 , then gas space  5 . 1  is filled under pressure-control with an inert gas (CO2 gas) which is at a filling pressure. The liquid filling material is fed under control to tank  5  over a supply line which is not shown. 
     In a housing  6  of filling element  3  there is configured among other things a liquid channel  7  which is connected via a line  8  to liquid space  5 . 2  of tank  5 . In liquid channel  7  there is provided a liquid valve  9  for the controlled delivery of the liquid filling material across an annular discharge port  10  which concentrically encircles a vertical filling element axis FA and which is formed on the underside of filling element  3  by the local open end of liquid channel  7 . At discharge port  10  there is provided a centering tulip  11  with seal  12  which annularly encircles discharge port  10  and against which respective bottle  2  lies pressed with its bottle mouth  2 . 1 , i.e. in sealed position, during the filling, in particular also during the pressure-filling. 
     Liquid valve  9  consists essentially of a valve body  9 . 1  which is disposed in liquid channel  7  and which interacts with a valve seat configured on the inner surface of liquid channel  7 . In the depicted embodiment, valve body  9 . 1  is provided or configured on a valve tube or gas tube  13  disposed on the same axis as filling element axis FA and open at both ends and which both acts as a valve stem to actuate liquid valve  9  and for this purpose interacts with an actuator  14  with which gas tube  13  and hence valve body  9 . 1  can be moved through a predetermined stroke axially on filling element axis FA (double arrow A) to open and close liquid valve  9 . 
     Gas tube  13  protrudes by its lower open end through discharge port  11  and beyond the underside of housing  6  and so during filling extends by that end into the interior of bottle  2 . Gas tube  14  extends by its upper, likewise open end into a closed gas space  15 . Reference number  16  indicates a probe which is arranged on the same axis as filling element axis FA and which determines the fill height in respective bottle  2 , extending through gas tube  13  and protruding by its lower end out of the lower open end of gas tube  13 . Between the outer surface of probe  16  and the inner surface of gas tube  13  there is configured an annular gas channel  17  which is open at the lower end of gas tube  13  and which at the upper end of gas tube  13  is connected to gas space  15  in the manner described in more detail below. 
     Gas space  15  configured inside housing  6  is part of a gas path system or gas channel system which exhibits a plurality of controlled gas paths with associated control valves  18 . 1 ,  18 . 2  and  18 . 3 . These control valves  18 . 1 ,  18 . 2  and  18 . 3  which in the depicted embodiment are pneumatically actuated are part of a control valve array  18  which—as is known to the skilled person—is used to control different filling methods or their process or filling phases, among other things by the controlled connection of gas paths of the gas path system or gas channel system with annular channels  19 ,  20  and  21  which are provided on rotor  4  for filling elements  3  in common and of which ring channel  20  is connected by a line  22  to gas space  5 . 1  of tank  1  so that ring channel  20  also carries the pressurised inert gas. 
     In the case of pressure-filling, before the actual filling phase, at least a pre-stressing of bottles  2  takes place with the pressurised inert gas which when control valve  18 . 2  is open flows as pressure gas from ring channel  20  across gas space  15  and gas channel  17  into bottle  2  arranged in sealed position at filling element  3 . During the subsequent filling phase and in particular during the rapid filling phase when liquid valve  9  is open the inert gas displaced out of the bottle interior by the filling material flowing into bottle  2  is returned as return gas to ring channel  20  through gas channel  17 , gas space  5  and open control valve  18 . 2 . 
     The duration of the pre-stressing of respective bottle  2  is determined among other things by the effective flow cross-section of the gas path through which the pressure gas flows from ring channel  20  into bottle  2 . The filling rate or flow rate at which the liquid filling material flows through discharge port  10  during the filling phase and in particular during the rapid filling phase of respective bottle  2  is determined among other things by the height of the filling material level N in tank  5  and by the effective flow cross-section of the gas path through which the return gas passes to ring channel  20 . To achieve a highest possible output of the filling system (number of filled bottles per unit of time) while still maintaining a gentle filling of bottles  2  with the liquid filling material, it is among other things a requirement for the gas path for the pre-stressing of respective bottle  2  with the pressure gas or inert gas from ring channel  20  to exhibit the greatest possible effective flow cross-section so as to achieve short cycle times for the pre-stressing, while the gas path for the return gas should exhibit a reduced effective flow cross-section during the filling phase and in particular also during the rapid filling phase. To satisfy these requirements without an additional control valve of control valve array  18  and without involving additional attendant complexity in terms of design and/or circuitry engineering and/or control engineering, filling element  3  is provided among other things with two different gas paths for the pre-stressing and the filling/rapid filling which share a single control valve  18 . 2 . For this purpose control valve  18 . 2  is connected on its input side to ring channel  20  via a gas channel  23  and on its output side to gas space  15  via a gas channel  24  and a further parallel gas channel  25  with throttle  26 . The different gas paths formed for the pressure gas and the return gas by gas channels  24  and  25  are mechanically switched in the manner described below by actuator  14  of liquid valve  9 , i.e. in the depicted embodiment by gas tube  13  together with the opening and closing of liquid valve  9 . 
     Gas space  15  is schematically depicted in more detail in  FIG. 2 . Also depicted are in particular probe  16  which is extended out of gas space  15  and sealed at the top with the use of a seal  27  as well as the two gas channels  24  and  25  opening into gas space  15 , with the throttle  26  being in gas channel  25 . 
     The upper end of gas tube  13  is provided with an annular body  28  which encircles probe  16  concentrically and at a distance and which has a flange projecting radially away over the outer surface of the annular body at the top of the annular body, on which (flange) is attached a ring seal  29  encircling probe  16  concentrically and at a distance. When liquid valve  9  is closed, i.e. when gas tube  13  is lowered, ring seal  29  is spaced at a distance from inner surface  15 . 1  of gas space  15  which (inner surface) lies axially opposite it relative to filling element axis FA, and from mouth  24 . 1  of gas channel  24 . When liquid valve  9  is open, ring seal  29  lies against inner surface  15 . 1  in the region of mouth  24 . 1  and sealing the latter tight. In interaction with inner surface  15 . 1  which encircles mouth  24 . 1 , annular body  28  with seal  29  therefore forms a switching valve  30  which when liquid valve  9  is closed mouth  24 . 1  is open to gas space  15 . 
     When liquid valve  9  is closed and control valve  18 . 2  is open therefore there exists for the pressure gas during pre-stressing a gas path with a large flow cross-section out of ring channel  20  and through gas channel  24 , gas space  15 , the interior of annular body  28  which (interior) is open to gas space  15  across radial ports  31 , and across an end port  32 , and gas channel  17  which connects with the interior of annular body  28 . 
     When liquid valve  9  is open and control valve  18 . 2  is closed, i.e. during filling, in particular during rapid filling, there therefore exists for the return gas only a gas path with reduced flow cross-section into ring channel  20 , across gas channel  17 , radial ports  31  in annular body  28 , gas space  15  and gas channel  25  with throttle  26  which now determines or essentially determines the effective reduced flow cross-section of this gas path. 
     The embodiment of switching valve  32  depicted in  FIG. 2  also has particular advantages for a CIP cleaning of filling elements  3  because during this cleaning, a flow connection with a relatively large cross-section exists for the cleaning and/or sterilisation medium that is used between gas channel  17  and gas space  15  through ports  31  when liquid valve  9  is open. 
       FIG. 3  shows a modified embodiment in which, when liquid valve  9  is open, switching valve  30   a  formed by annular body  28   a  with ring seal  29   a  in interaction with inner surface  15 . 1  of gas space  15  creates a connection solely between gas channel  17  and gas channel  25  that exhibits throttle  26 , whereas when liquid valve  9  is closed, gas channel  17  also connects with gas channel  24 . For this purpose mouth  25 . 1  of gas channel  25  is executed as an annular port encircling probe  16 . Gas channel  24  opens out into gas space  15  such that it is always connected to gas space  15  whatever the state of valve  30   a . Annular body  28   a  exhibits no radial ports in this embodiment. 
     When liquid valve  9  is closed, valve body  29  is axially spaced from mouth  25 . 1  relative to filling element axis FA so that during the pre-stressing of respective bottle  2 , a flow connection from both gas channels  24  and  25  into gas space  15  and hence into gas channel  17  exists when control valve  18 . 1  is open. When liquid valve  9  is open, valve body  29  lies tight against the inner surface of gas space  15  surrounding mouth  25 . 1 , so that during the filling phase and in particular also during the rapid filling phase there exists a connection for the return gas from gas channel  17  solely into gas channel  25  with throttle  26 . 
     Reference sign  33  indicates a gas channel in which control valve  18 . 3  is arranged and which connects gas space  15  to ring channel  21 . This gas channel is used for example for relieving pressure in respective bottle  2  after the end of the filling phase, by control valve  18 . 3  being opened. 
     Control valve  18 . 1  is connected on its input side to gas channels  24  and  25  and on its output side via a gas channel  34  to ring channel  19  through which for example at the start of filling an evacuation of respective bottle  2  is effected controlled by control valve  18 . 1 , again across gas space  15 , additional switching valve  30  or  30   a  that is opened when the liquid valve  9  is closed, and gas channel  17 . 
       FIG. 4  shows a filling element  3   a  of a filling system  1   a . Filling element  3   a  differs from filling element  3  only in that the gas channel system in housing  6  does not exhibit gas channel  25  with throttle  26  but instead the restricting of the return gas during the filling phase or rapid filling phase of the filling process is integrated into switching valve  30   b  that corresponds to switching valve  30  or  30   a  ( FIG. 5 ). The components which correspond to filling element  3  in regard to their configuration and/or function are indicated in  FIG. 4  with the same reference numbers as in  FIG. 1 . 
       FIG. 5  depicts schematically gas space  15  of filling element  3   a . To form switching valve  30   b , gas tube  13  is again provided at its upper end which protrudes into gas space  15  with an annular body  28   b  having an end ring seal  29   b  and which concentrically encircles probe  16  at a distance, and in such a way as to create at its end an annular port  32   b  which encircles probe  16  and which is for the interior of annular body  28   b  which connects with gas channel  17 . Gas channel  24  opens out into gas space  15  and in such a way that its connection with gas space  15  is independent of the state of switching valve  30   b . When liquid valve  8  is closed, ring seal  29   b  is at a distance from inner surface  15 . 1  lying opposite it of gas space  15 , so that among other things during the pre-stressing of respective bottle  2 , when control valve  18 . 2  is open, the pressure gas guided out of ring channel  20  across gas channels  23  and  24  into gas space  15  is able to flow across the largest cross-section of port  32   b  into gas channel  17  and hence into bottle  2 . 
     When the liquid valve is closed, seal  29   b  lies tight against inner surface  15 . 1  so that port  32   b  is closed and it is now only through radial ports  31   b  which are provided in annular body  28   b  and whose total flow cross-section is very much smaller than the flow cross-section of port  32   b  that the return gas can pass at a greatly restricted rate out of gas channel  17  and into gas space  15  from where the return gas is then returned through gas channels  23  and  24  and open control valve  18 . 2  into ring channel  20 . 
     The invention has been described hereinbefore by reference to embodiments. It goes without saying that numerous variations are possible without departing from the concept underlying the invention. 
     Common to all embodiments described above is that switching valve  30 ,  30   a  or  30   b  is mechanically actuated with actuator  14  of liquid valve  9  and is realised with a valve body (annular body  28 ,  28   a ,  28   b  and seal  29 ,  29   a  and  29   b  respectively) which is provided on gas tube  13  acting as a valve stem for liquid valve  9 , so that a change of the flow cross-section for the pressure gas and the return gas is achieved without any additional control valve which would require additional circuit engineering and control engineering complexity. Other embodiments are of course also possible, in particular those in which the respective annular or valve body of the switching valve is formed by a section of gas tube  13  and/or the annular body or valve body is an element connected to the return gas tube. Moreover the invention is of course not limited to filling elements or filling systems having probes that determine the fill height, but also includes among other things filling elements and filling systems in which the filling material quantity introduced into the respective container is controlled by other means, for example by measuring the delivered filling material quantity and/or the weight of the respective container as it is filled. 
     LIST OF REFERENCE SIGNS 
     
         
           1 ,  1   a  Filling system 
           2  Bottle 
           2 . 1  Bottle mouth 
           3 ,  3   a  Filling element 
           4  Rotor 
           5  Tank 
           5 . 1  Gas space 
           5 . 2  Liquid space 
           6  Filling element housing 
           7  Liquid channel 
           8  Pipe 
           9  Liquid valve 
           9 . 1  Valve body 
           10  Discharge port 
           11  Centering tulip 
           12  Seal 
           13  Valve or gas tube 
           14  Actuator 
           15  Gas space 
           15 . 1  Inner surface 
           16  Probe 
           17  Gas channel 
           18  Control valve device 
           18 . 1 - 18 . 3  Control valve 
           19 ,  20 ,  21  Ring channel 
           22  Pipe 
           23 - 25  Gas channel 
           24 . 1 ,  25 . 1  Mouth 
           26  Throttle 
           27  Seal 
           28 ,  28   a ,  28   b  Annular body 
           29 ,  29   a ,  29   b  Ring seal 
           30 , 30   a ,  30   b  Switching valve 
           31 ,  31   b  Radial port 
           32 ,  32   a ,  32   b  Port 
           33 , 34  Gas channel 
         A Movement stroke of the valve body  9 . 1   
         N Level of the filling material surface in tank  5   
         FA Filling element axis