EP2969894B1 - Method and filling machine for filling cans or the like containers with liquid contents - Google Patents

Description

The invention relates to a method for filling cans or the like. Containers and to a filling machine according to the preamble of claim 9. The patent document US 5,501,253 discloses a filling machine according to the preamble of claim 9 and a corresponding method.

A method for filling containers, especially for pressure filling of containers in the form of bottles with a liquid product and associated filling machines are also known in various forms. In this case, it is also known in particular ( DE 100 64 954 A1 ), in sealing position on the filling element arranged bottles in a the actual filling phase preceding rinsing phase to remove air entrained in the bottle interior with a purge gas in the form of a CO ₂ gas, the purge gas centric here, ie in a vertical Füllelementachse in the interior of the bottle initiate and dissipate out of the bottle interior via a controlled gas path.

The object of the invention is to provide a method which, in particular in containers in the form of cans allows effective flushing of the container or can interior. To solve this problem, a method according to claim 1 is formed. A filling machine is the subject of claim. 9

A peculiarity of the invention is that when flushing the respective container, the introduction of the purge gas exclusively via a throttle of the second gas path (22) with reduced flow cross-section and the discharge of the purge gas from the respective container via the first gas path (26) with a much larger Flow cross-section, so that the purge gas flows despite a high throughput of the respective container with reduced purge gas pressure, ie this case in the container only a reduced pressure (compared to the ambient pressure) of about 0 bar to 3.0 bar, for example from about 0 bar to 2, 0 bar (overpressure) preferably from about 0.5 bar to 1 bar prevails. At least when filling, the second gas path 22 has its full, not reduced by the throttle flow cross-section, whereby a rapid biasing and filling of the container is achieved.

Containers in the context of the invention are in particular cans, including those which are commonly used for drinks, but also can-like containers in which the cross section of the container opening is only slightly smaller than the cross section of the container interior. The same method is also advantageous for the inert gas flushing of bottles.

For the purposes of the invention, "pressure filling" is generally to be understood as meaning a filling process in which the container to be filled rests in sealing position against the filling element and, as a rule, before the actual filling phase, ie before the liquid valve is opened via at least one controlled element in the filling element trained gas path with a pressurized gas clamping gas (inert gas or CO ₂ gas) is biased, which is then increasingly displaced during filling of the inflowing the container contents as return gas from the container interior, also via at least one controlled, in the filling element trained gas way. This pretensioning phase is preceded by further treatment phases, in particular flushing of the container interior with an inert gas, for example with CO ₂ gas or nitrogen, and likewise via the gas path formed in the filling element.

The expression "essentially" or "approximately" in the sense of the invention means deviations from the exact value by +/- 10%, preferably by +/- 5% and / or deviations in the form of changes that are insignificant for the function. Further developments, advantages and applications of the invention will become apparent from the following description of exemplary embodiments and from the figures.

Fig. 1

in schematischer Darstellung und in Draufsicht eine Füllmaschine zum Füllen von Behältern in Form von Dosen mit einem flüssigen Füllgut;

Fig. 2

in vereinfachter Darstellung eine Füllposition der Füllmaschine der Fig. 1 zusammen mit einer in Dichtlage am Füllelement angeordneten Dose;

Fig. 3

und 4 in schematischer Funktionsdarstellung zwei gesteuerte Gaswege des Füllelementes der Füllposition der Fig. 2;

Fig. 5

die Füllposition der Fig. 2 im CIP-Modus der Füllmaschine für eine CIP-Reinigung- und/oder CIP-Desinfektion;

Fig. 6

eine Darstellung wie Fig. 2 bei einer weiteren Ausführungsform der Erfindung

Fig. 7

und 8 in schematischer Funktionsdarstellung zwei gesteuerte Gaswege des Füllelementes der Fig. 6;

Fig. 9

und 10 in schematischer Darstellung einen gesteuerten Gasweg eines Füllelementes der Erfindung in verschiedenen Betriebszuständen;

The invention will be explained in more detail below with reference to the figures of exemplary embodiments. Show it:

Fig. 1

in a schematic representation and in plan view of a filling machine for filling containers in the form of cans with a liquid filling material;

Fig. 2

in a simplified representation of a filling position of the filling machine of Fig. 1 together with a arranged in sealing position on the filling element can;

Fig. 3

and FIG. 4 is a schematic functional illustration of two controlled gas paths of the filling element of the filling position of FIG Fig. 2 ;

Fig. 5

the filling position of Fig. 2 in the CIP mode of the filling machine for a CIP cleaning and / or CIP disinfection;

Fig. 6

a representation like Fig. 2 in a further embodiment of the invention

Fig. 7

and FIG. 8 is a schematic functional illustration of two controlled gas paths of the filling element of FIG. 6;

Fig. 9

and Figure 10 is a schematic representation of a controlled gas path of a filling element of the invention in various operating conditions;

The in the Fig. 1 Generally designated 1 filling machine is used for pressure filling of containers 2 in the form of cans with a liquid product, such as beer or soft drinks. The filling machine 1 is designed as such a revolving type with a rotor 3, which is driven circumferentially during the filling operation about a vertical machine axis MA and at its periphery a plurality of filling positions 4, which are supplied to the container 2 to be filled via a container inlet 5 and those the filled containers 2 are removed at a container outlet 6. On the angular region of the rotary movement (arrow A) of the rotor 3 between the container inlet 5 and the container outlet 6, the containers 2 are filled with their container axis parallel to the machine axis MA and coaxially or substantially coaxially with one axis FA of the filling station 4 are arranged. This process is described below for rotary filling machines, but works analogously with linear fillers, for example, can be filled here also PET bulk containers, so-called KEG for beer.

As the Fig. 2 shows, each filling station 4 consists essentially of a filling element 7, which is arranged together with the filling elements 7 of the remaining filling points 4 on the circumference of the rotor 3 and the filling system of the filling machine 1 forms. On the rotor 3 is still a common for all filling positions 4 and in the illustrated embodiment formed as a ring vessel Füllgutkessel 8, which is partially filled during the filling operation with the liquid contents, namely forming a lower liquid space 8.1 and a gas space 8.2, of a below a filling pressure P _F, for example, 3 bar to 5 bar inert gas, For example, CO ₂ gas or nitrogen is taken. Each filling element 7 is connected via its own, a flow meter 9 having product line 10 with the liquid space 8.1.

In the illustrated embodiment, two annular channels 11 and 12, which surround the machine axis MA and are common to all filling points 4 or filling elements 7, are provided on the rotor 3, of which the one in the Fig. 2 (second) upper annular channel 11 during the filling operation in the manner described in more detail below, the pressurized inert gas, such as CO ₂ gas or nitrogen leads. The (lower) first annular channel 12 serves as Rücksammelgaskanal for discharging gas from the respective filling element 7, in particular also when rinsing the container 2. The pressure in the second annular channel 11 is equal to or substantially equal to the filling pressure P _F in the gas space 8.2 or slightly smaller as this filling pressure P _F. The pressure in the first annular channel 12 is for example the atmospheric pressure or a negative pressure.

The filling element 7 is formed in a Füllelementgehäuse 13 with a liquid channel 14 which is connected at its upper portion to the product line 10 and on the underside of the filling element 7, an axis FA concentrically enclosing annular discharge opening 15 forms, via which the liquid product to the respective Container 2 flows during filling. In the liquid channel 14, a liquid valve 16 is provided in the flow direction of the filling material in front of the discharge opening 15, which is essentially formed by a valve body 18 arranged on a valve tappet 17. In the Fig. 2 the liquid valve 16 is shown in the closed state, in which the valve body 18 rests against a valve surface in the liquid channel 14. In order to open the liquid valve 16, the valve body 18 is raised with the valve tappet 17 arranged coaxially with the axis FA by a preferably pneumatically controlled actuating element 19. The valve stem 17 is designed as a gas pipe, with a gas channel 20 which is arranged coaxially with the axis FA at the underside in the region of the discharge opening 15 and is surrounded by this annularly open and opens at the upper end of the valve stem 17 in a housing 13 formed in the gas space 21.

In order to control the different phases of the filling process during the pressure filling of the container 2, a plurality of controllable gas paths are formed in the filling element housing 13. Via a controllable second gas path 22, the gas space 21 is controlled connected to the second annular channel 11. This second gas path 22, in the Fig. 3 is shown again as a functional diagram for better understanding, contains two control valves 23 and 24, which are arranged in the connection between the second annular channel 11 and the gas space 21 in series and which are pneumatically actuated valves in the illustrated embodiment. Parallel to the control valve 24, a throttle 25 is provided, which has a fixed reduced flow cross-section and with closed control valve 24 allows a gas flow in a parallel bypass with the reduced flow cross section of the closed control valve 24 over, so that when open control valve 23 by opening and closing the Control valve 24, the effective flow cross-section of the controlled second gas path 22 is variable.

Via a further controlled first gas path 26, which is likewise formed in the filling element housing 13, two return gas openings 27.1 and 28.1 can be connected to the first annular channel 12. The return gas openings 27.1 and 28.1 are respectively provided on the underside of the filling element 7, relative to the discharge opening 15 relative to the axis FA radially outwardly offset and also in the direction of the axis FA axially above the discharge opening 15. The return gas openings 27.1 and 28.1 are at the embodiment shown offset by 180 ° about the axis FA and form the lower openings or gates of Rückgaskanälen 27 and 28 which extend in the Füllelementgehäuse 13 from the respective return gas opening parallel or substantially parallel to the axis FA upwards. The return gas channels 27 and 28 are part of the controlled first gas path 26 and each contain a control valve 29 and 30. The control valves 29 and 30 are in turn in the illustrated embodiment pneumatically actuated valves. The inputs of the control valves 29 and 30 are each connected to a return gas channel 27 and 28, respectively. The outputs of both Control valves 29 and 30 are connected to the first annular channel 12. For better understanding, the controlled first gas path 26 with the Fig. 4 shown again in a functional diagram together with the annular channel 12.

The filling element 7 further comprises a centering bell 31, which at least during rinsing, toughening and filling with a ring seal 31.1 sealingly abuts against the opening edge of standing on a container support 32 container 2, so that the environment through the filling element 7, the centering 31st and the container 2 sealed space is formed, in which the discharge opening 15, the lower end of the gas channel 20 and the return gas openings 27.1 and 28.1 open. By a pneumatic actuator 33 in the form of, for example, the filling pressure P _F acted upon bellows centering tulip 31 is biased via a linkage 34 in its lower sealing against a container 2 position. Due to the interaction of a provided on the linkage 34 cam follower 35 with an outer, not rotating with the rotor 3 stroke, the centering 31 is raised for the insertion of a container 2 in the filling position 4 or for the removal of the filled container 2 from the filling position 4.

The control of the pneumatically actuated control valves 23, 24, 29, 30 between their open and closed state via electro-pneumatic valves 36, which in turn are controlled by the machine control of the filling machine 1. With the filling element 7 having filling machine is in particular a pressure filling of the container 2 with the following method steps possible:

1. introduction or insertion of the container 2 in the filling position. 4

For the introduction of the container 2 in the respective filling position 4, the liquid valve 16 are closed, the control valves 23 and 24 and thus the second gas path 22 is closed, the control valves 29 and 30 and thus the first gas path 26 are open and the centering tulip 31 against the effect the actuator 33 is raised.

2. Rinse the container interior with inert gas

For rinsing the container interior, the container 2 is in sealing position on the filling element 7, i. the centering tulip 31 is lowered with its concentric surrounding the axis FA ring seal 31.1 against the edge of the container opening tightly against the container 2. The liquid valve 16 is closed and the control valves 23, 29 and 30 are opened when the control valve 24 is closed. In this way, inert gas flows as purge gas from the annular channel 11 via the throttle 25 into the gas space 21 and from this via the gas channel 20 centrally or centrally into the interior of the container 2 and forms there an inert gas flow, the u.a. in the middle of the container 2 u.a. extends as far as the container bottom and from there along the inner surface of the container wall is directed outside upwards, as indicated at 37. About the return gas openings 27.1 and 28.1 and the opened first gas path 26, the purge gas and entrained with this air is discharged into the annular channel 12, for example, has atmospheric pressure or a negative pressure.

By the above-described specific embodiment of the filling element 7, in particular by the throttle 25 in the second gas path 22 and the two operatively parallel return gas channels 27 and 28 and control valves 29 and 30, ie by the hereby achieved compared to the flow cross-section of the throttle 25 significantly larger flow cross-section of the first gas path 26, this rinsing process is designed so that the entrained in the respective container air at a purge pressure P _S between the atmospheric pressure and an overpressure of about 0.5 bar to 2.0 bar, preferably from about 1.0 bar in the shortest Time is displaced from the container interior and replaced by the inert gas (for example, CO ₂ gas or nitrogen). This is achieved on the one hand by the fact that the purge gas is supplied to the container interior via the throttle 25 of the second gas path 22 and thereby the pressure of the purge gas flowing to the container 2 is significantly reduced compared to the pressure in the annular channel 11. However, this is also achieved by virtue of the fact that the outflow of gas from the interior of the container 2 takes place on an effective flow cross section which is much larger than the cross section of the throttle 25, namely via the two parallel gas paths 27 and 28, so that it comes to high gas flow rates within the respective container 2 at reduced purge pressure P _S , which can be supported by a negative pressure in the annular channel 12 yet. Furthermore, a disturbing the flushing stronger turbulence of the purge gas is at least largely avoided with air.

This optimal purging or the optimal purging gas flow within the container interior are achieved, in particular, by the fact that the return gas openings 27.1 and 28.1 are arranged offset by 180 ° around the axis FA for the gas reflux and directly adjacent to this seal within the ring seal 31.1 and thus directly the inside of the opening edge of the container 2 are, ie the radial distance of the return gas openings 27.1 and 28.1 from the axis FA is equal to or only slightly smaller than the corresponding distance of the inside of the ring seal 31.1 from the axis FA.

The rinsing time is significantly reduced, which leads to a shortening of the rinsing time and thus to an increase in the performance of the filling machine 1 (number of filled containers 2 per unit time). By a constant purge time, the gas flow rate and thus the Inergasverbrauch is lowered.

3. biasing the container interior with inert gas

For this purpose, the container 2 is still in lowered centering bell 31 in sealing position on the filling element 7. The liquid valve 16 and the control valves 29 and 30 and thus the first gas path 26 are closed. The two control valves 23 and 24 are opened, so that the inert gas as a biasing gas (CO ₂ gas or nitrogen) without throttling through the throttle 25 via the fully open second gas path 22 into the gas space 21 and from there via the gas passage 20 in the Container interior can flow, so that this is temporarily biased at a pressure which is equal to or substantially equal to the filling pressure P _F.

4. pressure filling of the container interior

The container 2 is still in sealing position on the filling element 7. The control valves 29 and 30 and thus the first gas path 26 are closed. The control valves 23 and 24 are open. For the introduction of the filling phase, the liquid valve 16 is opened, so that the liquid product flows into the container via the discharge opening 15, through the conical design of the liquid channel 14 in the region of the discharge opening 15 along the container inner surface. The displaced from the contents of the container 2 inert gas is returned via the fully open gas passage 20 and the fully opened second gas path 22 into the annular channel 11. The amount of filling material flowing to the container 2 is monitored by the flow meter 9. If the required filling quantity is reached, the liquid valve 16 is caused to be closed by a measuring signal of the flow meter 9 via the actuating element 19.

5. Relieve the container interior of the filled container

In still in sealing position on the filling element located container 2 and closed liquid valve 16 and closed control valves 23 and 24 is carried out by opening at least one of the control valves 29 and 30, but preferably both control valves 29 and 30 relieving the contents of the contents not occupied headspace of the container. 2 It is possible that for a partial unloading initially only one control valve 29 or 30 and only for a subsequent complete unloading and the other control valve 30 or 29 is opened.

6. Release the filled container 2 and push out this container

After relieving takes place with the liquid valve closed 16, closed control valves 23 and 24, but still open control valves 29 and 30, a lifting of the centering bell 31 through the cooperating with the cam roller cam 35 so that the filled container 2 can be removed at the container outlet 6.

In principle, further process steps are possible with the filling element 7, for example a slow filling and / or a slow filling before closing the liquid valve 16, in each case by virtue of the fact that only the control valve 23 is opened for this purpose and the control valve 24 is closed.

The Fig. 5 shows the filling element 7 in a cleaning and / or disinfection operating state or CIP mode (CIP cleaning and / or disinfection) of the filling machine 1. In this state, the filling elements 7 are each at the bottom of their Füllelementgehäuses 13 with a closure, provided for example in the form of a flushing cap 38, which forms a closed to the environment flushing chamber 39 into which the discharge opening 15, the lower, open end of the gas channel 20 and the two return gas openings 27.1 and 28.1 open. During this CIP cleaning and / or disinfection, the product vessel 8 is filled with a liquid cleaning and / or disinfecting medium or CIP medium. The two control valves 23 and 24 and thus the second gas path 22 are closed, the control valves 29 and 30 are opened, so that the CIP medium from the boiler 8 through the liquid passage 14, through the opened liquid valve 16, through the discharge opening 15, through the purge chamber 39 and can flow through the two return gas channels 27 and 28 in the annular channel 12, from which the CIP medium is discharged. Even with this CIP cleaning and / or disinfection, the first gas path 26 with the two open control valves 29 and 30 enables a large effective flow cross-section for the CIP medium and thus a high CIP medium throughput ensuring intensive treatment. In principle, it is possible to treat, for example, with closed control valves 29 and 30 and still open liquid valve 16 and open control valves 23 and 24 and the second gas path 22 with the CIP medium from the Füllgutkessel 8, which is then discharged via the annular channel 11.

The peculiarity of the filling machine 1 and the filling system 7 formed by the filling of this machine is thus, inter alia, that when purging the respective container, the introduction of the purge gas exclusively via the throttle 25 at a reduced flow cross-section, while the discharge of the purge gas from the respective container takes place over the first gas path 26 at a much larger flow cross-section, so that the purge gas despite a high Throughput the respective container 2 flows with reduced purge gas pressure, ie in this case in the container 2 a reduced over the filling pressure P _F overpressure of about 0 bar to 2.0 bar, for example from about 0.5 bar to 2.0 bar, preferably from about 0 , 5 - 1,0 bar prevails. Both during preloading, as well as during filling, the second gas path 22 through the open control valves 23 and 24 its full flow cross-section, whereby a rapid biasing and filling of the container 2 is achieved.

By forming the first gas path 26 with two effectively parallel return gas channels 27 and 28, it is possible to realize the larger in comparison to the second gas path 22 when flushing flow cross section characterized in that for all control valves 23, 24, 29 and 30 valves with basically identical structure are used, each biased by internal spring means in an initial state and are transferred by applying a control pressure in its other state. Here, however, at the control valves 23 and 24 are preferably designed so that they are open in the idle state. The control valves 29 and 30 are preferably designed so that they are closed when at rest. This allows a simplification of the control of the control valves 23, 24, 29 and 30 by the electro-pneumatic valves 36, ie only for the control valve 23, a separate electropneumatic valve 36 is required, while the control valves 24, 29 and 30 are driven by a common electropneumatic valve 36 which in the activated state, ie during flushing by acting on a control pressure, the control valve 24 closes and the control valves 29 and 30 opens, while biasing and filling because of the non-activated electro-pneumatic control valve 36, the two control valves 23 and 24 opened by their spring means and the control valves 29 and 30 are closed by their spring means. The third in the Fig. 2 shown electro-pneumatic control valve 36 serves to control the actuating element 19th

FIG. 6 shows, as a further embodiment, a filling machine 1a or one of the filling elements 7a of this filling machine. The filling machine 1a initially differs from the filling machine 1 in that the rotor 3 has a further ring bowl 40 is provided, which serves as a common discharge channel for all filling elements 7a.

The filling element 7a differs from the filling element 7 essentially only in that instead of the controlled second gas path 22, a controlled second gas path 22a is provided, in the connection between the annular channel 11 and the gas space 21. This second gas path 22a is in the Fig. 7 In effect, parallel to the throttle 25, a check valve 41 is arranged, which is designed so that it closes for a flow from the annular channel 11 and opens for flow into the annular channel 11. The process steps rinsing and biasing the container 2 with the standing under filling pressure P _F inert gas from the annular channel 11 and pressure filling the container 2 while returning the case from the containers 2 displaced inert gas is analogous to the method described in connection with the filling element 7, wherein the Rinsing with the open control valve 23 and blocking check valve 41 again with the throttle 25 in cooperation with the two open gas paths 27 and 28, the purge gas from the annular channel 11 with reduced purge pressure P _{S introduced} into the container 2 and this flows through with high throughput. The biasing of the container 2 is carried out at the filling element 7a with open control valve 23 alone on the throttle 25. When pressure filling the container 2, the displaced by the inflowing inert gas with open control valve 23 via both the throttle 25, and mainly via the opening check valve 41 returned to the annular channel 11.

For this purpose, the filling element 7a an additional controlled gas path 42, and as a connection between the return gas opening 27.1 and the annular channel 40. This gas channel is in the FIG. 8 shown schematically. When unloading the filled container 2, the control valves 23, 29 and 30 are closed and the control valve 24 of the gas path 42 is opened, so that the discharge takes place in the annular channel 40.

In the case of the filling element 7a, too, the flow of the inert gas during rinsing, prestressing and filling takes place via the second gas path 22a, specifically with a reduced flow cross section during rinsing and prestressing, but with a non-reduced flow cross section during filling.

FIGS. 9 and 10 each show in a schematic partial representation and in section the Füllelementgehäuse 13 in the region of the gas space 21 at a filling element 7 b according to another embodiment of the invention, with a controlled second gas path 22b in the connection between the annular channel 11 and the gas channel 20. In this Embodiment, the gas chamber 21 is part of the controlled second gas path 22b with a variable throttle 43, which is operatively arranged in series with the control valve 23 in the second gas path 22b and which between a first state with reduced throttle cross-section ( Fig. 10 ) and a second state with an enlarged throttle cross-section ( Fig. 9 ) is controllable. The throttle 43 is formed at the upper end of the valve stem 17, namely at a local throttle opening 20.1 of the gas channel 20 such that this opening when the liquid valve 16 is open, ie when the valve stem 17 is raised, a larger opening cross-section (FIG. Fig. 9 ), than when the liquid valve 16 is closed, ie when the valve stem 17 is lowered (FIG. Fig. 10 ). This automatically and without the need for a further control valve is achieved, in turn, the flushing and biasing of the respective container from the annular channel 11 via the second gas path 22b at a reduced flow cross-section ( Fig. 10 ) and the return of the inert gas displaced from the filling material during pressure filling over an enlarged cross section of the second gas path 22b (FIG. Fig. 9 ) respectively. In the illustrated embodiment, a throttle body 44 which is not moved along with the valve element housing 13 and is arranged coaxially with the axis FA, which extends into the throttle opening 20.1 and leaves the different flow cross section free in the first and second state of the throttle 43. The throttle body 44 is for this purpose, for example, mushroom-shaped, so that in the first state ( Fig. 10 ) is located with its head in the throttle opening 20.1 and in the second state ( Fig. 9 ) the head is received in an extension of the gas channel 20 and the reduced cross-section portion of the throttle body 44 is located in the throttle opening 20.1. LIST OF REFERENCE NUMBERS 1, 1a filling Machine 26 controlled (first) gas path 2 container 27.28 Return gas channel 3 rotor 27.1, 28.1 Return gas opening 4 filling position 29, 30 control valve 5 container inlet 31 centering bell 6 container outlet 32 container carrier 7,7a filler 33 actuator 8th Füllgutkessel 34 linkage 8.1 liquid space 35 follower 8.2 headspace 36 electro-pneumatic 9 Flowmeter control valve 10 product line 37 Flow of the inert gas during rinsing 11, 12 annular channel 13 filling element 38 flushing cap 14 liquid channel 39 Wash cabinet 15 discharge opening 40 additional ring channel (discharge channel) 16 liquid valve 17 tappet 41 check valve 18 valve body 42 controlled gas path 19 actuator 43 throttle 20 gas channel 44 throttle body 20.1 throttle opening A Direction of rotation of the rotor 3 21 headspace FA filling element 22, 22a, 22b controlled gas path MA machine axis 23.24 control valve 25 throttle

Claims (15)

1. Method for filling cans or the like containers with a liquid in a filling phase of a filling process wherein, in at least one purge phase that temporally precedes the filling phase, the container interior of the respective container (2), which is arranged in a sealed position at the filling element (7, 7a), is purged with a purge gas in the form of an inert gas that is introduced into the container interior, and the purge gas flowing through the container interior at a purge gas pressure (Ps) is drained from the container interior, wherein the purge gas pressure (Ps) in the container interior is equal to an overpressure in comparison with ambient pressure of 0 - 2.0 bar, preferably from 0.5 bar to 1.0 bar, wherein the purge gas is drained out of the container interior via at least two return gas openings (27.1, 28.1) of a first controlled gas path (26) of the filling element (7, 7a), the first gas path (26) of the filling elements (7, 7a) comprising at least two gas channels (27, 28) with in each case one control valve (29, 30), wherein the gas channels (27, 28) in each case form a return gas opening (27.1, 28.1), wherein the purge gas is conveyed via a second controlled gas path (22, 22a, 22b) out of a gas chamber or a second annular channel (11) common to all the filling elements (7, 7a) of the filling machine (1, 1a), to the container interior via a controllable choke arrangement (24, 25; 25, 41; 43), which can be switched between a first state, in which it chokes the inert gas flow, and a second state in which it does not choke the inert gas flow, and wherein the choke arrangement (24, 25, 25, 41; 43), during the purging, is in its first state in which it reduces the pressure of the purge gas to the purge pressure (Ps).
2. Method according to claim 1, characterised in that a first annular channel (12) exhibits an underpressure.
3. Method according to claim 1 or 2, characterised by the use of filling elements (7, 7a), in which the return gas openings (27.1, 28.1) are offset by 180° about the filling element axis FA and/or are provided immediately adjacent to a ring seal (31.1), against which the container is in contact with its container mouth in a sealing position at the filling element (7, 7a).
4. Method according to claim 1, characterised in that the inert gas which, during the pressure filling of the containers (2), is forced by the liquid contents out of the container interior, is conveyed back via the second controlled gas path (22, 22a, 22b) into the gas chamber or into the second annular channel (11), and that in this situation the choke arrangement (24, 25, 25, 41; 43) is in its state in which it is not choking the inert gas flow.
5. Method according to any one of the preceding claims, characterised in that the choke arrangement is formed from a control valve (24) and a choke (25) arranged parallel to this valve, or by a non-return valve (41), which opens for a flow into the gas chamber or the second annular channel (11), and closes for a flow in the opposite direction, and by a choke arranged parallel to the non-return valve (41), or by a choke arrangement (43) with a changeable flow cross-section.
6. Method according to claim 5, characterised in that the choke arrangement (24, 25; 25, 41, 43), at least at the opening of a liquid valve (16) of the filling element (7, 7a), is switched from the first state into the second state.
7. Method according to any one of the preceding claims, characterised in that a valve tappet (17), which is moved at the opening and closing of the liquid valve (16), is a part of the choke arrangement or is the controllable choke (43) forming this choke arrangement.
8. Method according to any one of the preceding claims, characterised in that, during a pretensioning of the containers (2) with the inert gas preceding the filling phase, as well as during the filling phase, the control valves (29, 30) of the return gas channels (27, 28) are closed.
9. Filling machine for the filling, in particular the pressure filling, of cans or like containers (2), with a plurality of filling elements (7, 7a) arranged on a circulating transport element (3), such as a rotor, in each case with a liquid channel (14) formed in a filling element housing (13) and comprising at least one liquid valve (16), which is connected to a filling product vessel (8) at the transport element (3) and forms on an underside of the filling element (7, 7a) at least one filling product dispensing opening (15), with a container contact surface formed from a ring seal (31.1) at a housing part (31), against which opening the respective container (2) is in contact during the filling, sealed against the filling element, with a first controlled gas path (26), which opens on the underside of the filling element housing (13) and, related to a filling element axis (FA), opens inside the ring seal or the housing part (31), as well as with a second controlled gas path (22, 22a, 22b), which opens centrically on the underside of the filling element (7, 7a), related to the filling element axis (FA), and is connected to a gas chamber or to a second annular channel (11), which is provided as a channel for conducting an inert gas under pressure for all the filling elements (7, 7a) jointly at the transport element (3), and wherein the second gas path (22, 22a, 22b) comprises a controllable throttle arrangement (24, 25; 41, 25; 43), which can be controlled between a first state in which the gas flow is choked, and a second state in which the gas flow is not choked, characterised in that the first controlled gas path (26) comprises at least two return gas channels (27, 28), in each case opening on the underside of the filling element housing (13) via a return gas opening (27.1, 28.2), in each case with an independent control valve (29, 30) in each return gas channel (27, 28) for draining the purge gas out of the container interior via the at least two return gas openings (27.1, 28.1) of the first controlled gas path (26).
10. Filling machine according to claim 9, characterised in that the housing part comprising the ring seal (31.1) is a centring tulip (31).
11. Filling machine according to claim 9 or 10, characterised in that the first controlled gas path (26), or its return gas channels (27, 28) respectively, open into a first annular channel (12) common to all filling elements (7, 7a).
12. Filling machine according to any one of the preceding claims 9 to 11, characterised in that the at least two return gas openings (27.1, 28.1) are arranged offset by 180° to one another about the filling element axis (FA), which is equal or approximately equal to half the diameter of the ring seal (31.1).
13. Filling machine according to claim 9, characterised in that the choke arrangement is formed from a choke (25) with a fixed flow cross-section and a control valve (24) arranged parallel to the choke, or from the choke (25) with fixed cross-section and a non-return valve arranged parallel to the choke, which opens for a flow into the gas chamber or second annular channel (11) and closes for a flow in the opposite direction, or from a controllable choke (43) with changeable cross-section.
14. Filling machine according to any one of the preceding claims 9 to 14, characterised in that the second gas path (22b) is formed on a part length by a gas channel (20) provided in a valve tappet (17) of the liquid valve (16), and that the valve tappet (17) moved axially at the opening and closing of the liquid valve, is a part of the controllable choke (43) in the form of its end remote from the dispensing opening (15), and that the gas channel (20) formed in the valve tappet (17) comprises for this purpose a choke opening (20.1), opening at this end into a gas chamber of the second gas path (22b) and interacting with a choke body (44), which, in a position of the valve tappet (17) corresponding to the closed state of the liquid valve (16), closes the choke opening (20.1) as far as a reduced flow cross-section, and in a position of the valve tappet (17) corresponding to the opened state of the liquid valve (16) clears the choke opening (20.1) for a larger flow cross-section.
15. Filling machine according to any one of the preceding claims 9 to 15, characterised in that, in the second gas path (22, 22a, 22b), in series with the controllable choke arrangement, a further control valve (23) is provided for the controlled opening and closing of this gas path, and that the further control valve (23) is opened for the purging, pretensioning, and pressure filling of the containers (2), and, when the containers to be filled are pushed under the filling element (7, 7a), is closed at the pressure-relieving of the containers (2) after the filling, and when the filled containers are removed.

Images