EP0554690A1 - Method for filling bottles or similar containers with a liquid product and apparatus for carrying-out this method - Google Patents

Abstract

In the case of a method or an apparatus for filling bottles (11) or similar containers with a liquid material using a liquid valve (1), the container is preloaded in a preloading phase with a return gas, which contains an inert gas, from a return gas duct (27) in a first step and from a further gas duct (8) in a second step. In a subsequent filling phase, the return gas, which is displaced from the container by the material entering, is at least temporarily discharged into the return gas duct (27). To reduce consumption of the inert gas and/or to use the inert gas in optimum fashion, return gas from the further gas duct (8) is used for preloading in the second step and the return gas, which has been displaced from the container, is at least temporarily returned into this further gas duct during the filling phase. To compensate for a shortage of gas in the gas duct and to maintain a predetermined pressure in each case, inert gas is fed into the return gas duct, but also into the further gas duct which is connected to the return gas duct. <IMAGE>

Description

The invention relates to methods according to the preamble of claim 1 and to a device according to the preamble of claim 9.

Such a method and an associated device for filling a liquid, especially carbonated filling material under counterpressure in bottles or similar containers are known (EP-A-0 331 137). It has already been proposed to use return gas from a return gas duct of the filling machine in which the return gas displaced when the containers are filled is removed to reduce the consumption of inert gas or CO₂ gas in the pretensioning phase for purging and partial pretensioning of the respective container becomes. This return gas channel contains the return gas under a predetermined pressure and is connected to a line via which excess return gas is discharged, for example, to the atmosphere or to a system for processing inert gas. By using the return gas from the return gas channel for purging and partially prestressing the containers, there is a reduction in the consumption of inert gas. It is disadvantageous, however, that the entire inert gas displaced from the respective container during filling reaches the return gas duct, the pressure of which is well below the filling pressure, i.e. is below the pressure that the interior of the respective container has at the end of the prestressing. The inert gas displaced during filling can therefore only be reused for purging and partial prestressing.

The object of the invention is to develop a method or a device of the type mentioned at the outset in such a way that there is also a substantial reduction in the amount of inert gas required under filling pressure.

To achieve this object, a method according to the characterizing part of patent claim 1 and a device according to the characterizing part of patent claim 9 are formed.

In the case of the invention, the return gas channel, from which the return gas displaced by the incoming filling material from a container is at least temporarily received during the filling phase and from which the partial preloading and preferably also the purging of the container preceding this preloading takes place, is not a gas channel, from which excess return gas is derived, but a gas channel, to which fresh inert gas is fed, as well as the further gas channel, in order to maintain the respectively predetermined pressure in the return gas channel and the further gas channel, ie Compensate for return gas or CO₂ gas deficits, which result at least from the pretensioning and the previous purging of the containers. In a preferred embodiment of the invention, this supply of the inert gas to the return gas channel takes place via the further gas channel, the gas pressure of which is preferably significantly higher than the gas pressure of the return gas channel.

The further gas channel in the invention is, for example, a gas space formed in the boiler above the liquid filling material or the interior of an additional intermediate container. The interior of this intermediate container is then preferably connected to this gas space via a fluid connection which only allows a gas flow from the gas space of the boiler into the intermediate container.

In the case of the invention, not only is the final prestressing of the respective container from the further gas channel, but at least temporarily the displaced return gas is also returned to it during the filling phase, so that with respect to this, to the further gas channel, ie to an area with the higher gas pressure returned gas quantity no pressure losses occur in the return gas intended for further use.

In the invention, the interior of the respective container is preferably flushed with the return gas from the return gas channel during the preloading phase and / or the container is treated with a hot sterilization medium, preferably water vapor and / or before the respective container is preloaded The interior of the container is evacuated prior to prestressing, means being provided in a device for filling bottles or similar containers which enable these aforementioned method steps.

Furthermore, in the invention, the pressure in the return gas channel is preferably adjusted to a value below the pressure of the further gas channel and kept constant and / or the pressure in the further gas channel is kept at a predetermined, constant value. The pressure in the further gas channel is preferably kept at a constant value relative to the filling pressure or to the pressure of the liquid filling material in the boiler, preferably at a value below the filling pressure, when using a boiler completely filled with the liquid filling material.

The level in the boiler is kept constant, for example, at a predetermined level, or appropriate means are provided.

The fill level in the boiler is preferably set to a level which is above a level which the fill level has in the respective container at the end of the filling phase.

Preferably, the gas displaced from the interior of the container during flushing or the air displaced in the process is discharged to a collecting duct open to the atmosphere and / or after the filling phase has ended, the container is partially relieved of the pressure of the return gas duct, with subsequent residual relief Atmospheric pressure.

Developments of the invention are the subject of the dependent claims.

Fig. 1

in vereinfachter Darstellung und im Schnitt eines der am Umfang eines um eine vertikale Drehachse umlaufenden Rotors vorgesehenen füllrohrlosen Füllelemente einer Füllmaschine umlaufender Bauart;

Fig. 2

in einer Darstellung gemäß Fig. 1 eine weitere, abgewandelte Ausführung der Erfindung;

Fig. 3

in Teildarstellung eine abgewandelte Ausführung der Fig. 1.

The invention is explained in more detail below with reference to the figures using exemplary embodiments. Show it:

Fig. 1

in a simplified representation and in section of one of the filling tube-less filling elements of a filling machine of the rotating type provided on the circumference of a rotor rotating around a vertical axis of rotation;

Fig. 2

1, a further, modified embodiment of the invention;

Fig. 3

in a partial representation a modified embodiment of FIG. 1.

In the figures, 1 is a filler-less filler element of a rotating design of a two-chamber filler, which is arranged together with other similar filler elements 1 on the circumference of a rotor part 2 of the filler machine that rotates around a vertical machine axis.

The filling element 1 essentially consists of a multi-part housing 3, in the housing part 3 'of which a liquid channel 4 is formed, in which a liquid valve 5 with a valve body 6 is provided. The liquid channel 4 is connected to a ring container or bowl 7 formed in the rotor part 2, which is only partially filled with the liquid filling material, so that there is a gas space 8 in the partly filled ring bowl 7 above the level N of the level of the liquid filling material results in pressurized CO₂ gas. In this embodiment, the gas space 8 forms the “further gas channel”. The liquid filling is a still or carbonated drink, e.g. beer, wine, etc.

In the flow direction after the liquid valve 5, the liquid channel 4 forms on the underside of the filling element 1 a vertical filling element axis VA and a gas pipe 9 connected to the valve body 6 concentrically enclosing an annular outlet opening 10 Bottle 11 located in the sealing position with the filling element 1. A seal 14 is provided on a centering bell 13 for tightly pressing the mouth 12 of the bottle 11 against the filling element 1.

The gas pipe 9, which is open at its lower end, forms a gas path 15 which extends through the valve body 6 and through an actuating device (not shown) for the liquid valve 1 into a space 16.

A control valve device 23, which forms various valve functions or valves 17 - 22, is assigned to the filling element. This control valve device 23, which is designed as a slide control device and cooperates with an actuating lever 24 with stationary control elements, furthermore has a control valve 25, which can be controlled independently of the valves 17 - 22, namely by its own actuating element 26, which is an electrical, but preferably pneumatic actuating element .

A return gas duct 27 is formed on the rotor part 2. Furthermore, a collecting duct 28 is provided on the rotor part 2.

The valves 17-22 each have two connections, between which there is a flow connection when the valve is open. When the valve 17-22 is blocked, this flow connection is interrupted. In the following description, the closed position of the valves 17-22 is assumed, unless the open state is expressly indicated for a specific valve 17-22.

In particular, the following connections exist to the valves 17-22 or to their connections:
The valves 19 and 20 are each connected with their lower connection in FIG. 1 to a connecting line 29 which is connected to the space 16.
The valves 18 and 21 are each connected with their lower connection in FIG. 1 to a connecting line 30 which is connected to the connecting line 29 via the control valve 25.
The valves 17 and 22 are connected with their lower connection in FIG. 1 to a connecting line 31, which opens the liquid channel 4 in the flow direction behind the liquid valve 5 and in front of the outlet opening 10.

With regard to the upper connections of the valves 17-22 in FIG. 1, the following connections exist:
Valves 17 and 22 via a connecting line 32 to the collecting duct 28;
Valves 18 and 20 via a connecting line 33 to the return gas duct 27;
Valves 19 and 21 via a connecting line 34 to gas space 8.

In the connections of the valve 20 with the return gas channel 27, the valve 21 with the gas space 8 and the valve 22 with the collecting chamber 28, a throttle 34 'is provided, which can however have very different dimensions in the individual connections or gas paths.

The filling element 1 also has a probe 35 for controlling the filling level. This probe 35, which is arranged coaxially with the axis VA, is enclosed by the annular gas channel 15.

The ring bowl 7 is connected via a supply line 36, which opens into the ring bowl 7 at the bottom area, to a supply container, not shown, for the liquid filling material. In the supply line 36, a control valve 37 is arranged, which is controlled by a level control 38 taking into account a signal supplied by a level meter 39 in such a way that the level of the liquid filling material present in the ring bowl 7 is kept constant or essentially constant at the predetermined level N. .

A supply line 40 for CO₂ gas is also connected to the ring bowl 7, which opens into the gas chamber 8 in the area of the top of the ring bowl 7. In the supply line 40, a control valve 41 is provided, which is controlled by a pressure control 42 on the basis of the signal supplied by a pressure meter 43 so that there is a CO₂ gas pressure with a predetermined constant or in the supply line 40 after the control valve and thus in the gas space 8 results in a substantially constant value. The pressure meter 43 is arranged in the part of the supply line 40 which lies between the control valve 41 and the gas space 8.

The gas space 8 is connected to the return gas duct 27 via a connecting line 44. In the connecting line 44, a control valve 45 is provided, which is controlled by a pressure control 46 as a function of a signal supplied by a pressure gauge 47 such that a predetermined constant or substantially constant pressure is obtained in the return gas duct 27, which pressure is less than that Pressure in the gas space is 8.

With the design described, the following procedure is possible when filling the bottle 11 with the liquid contents:

1. Position the bottle 11 and the filling element 1.

The bottle 11 is brought into a sealing position with the filling element 1 using the seal 14.

2.Purging from the return gas duct 27.

In a first functional position of the control housing or the control valve arrangement 23, the valves 17 and 18 are opened. About the control valve 25 is also opened so that CO₂ from the return gas channel 27, the valve 2, the control valve 25 and the gas channel 17 can get into the bottle 11 for purging and the air displaced can flow out via the valve 1 in the collecting channel 28 .

After a predetermined flushing time, the control valve 25 is closed. The degree of pre-rinsing of the bottle 11 can be made variable via this time function.

3. Partial prestressing from the return gas duct 27.

The control valve device is switched to a second functional position. Here, the valve 17 is closed again, while the valve 18 remains in the open state. By opening the control valve 25, the connection between the gas pipe 9 and the return gas channel 27 is made, so that CO₂ gas can flow into the bottle 11 from the return gas channel 27 and there the pressure regulated in the return gas channel 27 is set, which, however, is still somewhat below the desired, final preload pressure.

4. Residual prestressing from the ring bowl 7 or gas space 8.

The control valve device 23 is switched to a third functional position. The valve 18 is closed and the valve 19 is opened. The bottle 11 is now biased to the filling pressure set in the gas channel 8.

5. Slow filling phase.

The liquid valve 5 is opened by an actuating device, not shown, preferably by a pneumatic actuating device which is controlled by an electromagnetic valve.

Immediately afterwards, the control valve device 23 is switched to a fourth functional position. The valve 19 is closed and the valve 20 is opened, so that there is a return gas path from the bottle 11 to the return gas duct 27 via the gas pipe 9, the opened valve 20, the associated throttle 34 ', specifically for filling the bottle 11 from this displaced CO₂ gas. The filling speed is determined here by the cross section of the throttle 34 ′ and the pressure difference between the interior of the bottle 1 and the return gas duct 27.

In this fourth functional position of the control valve device 23, the valve 21 is also opened, specifically in preparation for a return gas path from the gas pipe 9 into the gas space 8. However, this further return gas path is interrupted by the closed control valve 25.

6. Fast filling phase

After a certain period of time, which determines the slow filling phase, the control valve 25 is opened, so that the aforementioned additional return gas path via the valve 21 and the associated throttle 34 ′ to the gas space 8 takes effect. This additional return gas path via the opened control valve 25 and the opened valve 21 results in an additional component for the filling speed, which is due to the higher level N of the liquid filling material in the ring bowl 7 compared to the bottle 11 and the effective diameter of the valve 21 Throttle 34 'is determined.

The filling speed in the rapid filling phase is also determined by the amount of CO₂ gas flowing off via the opened valve 20 and the throttle 34 'located there.

7. Braking and correction phase

After the time provided for the rapid filling phase has elapsed, the control valve 25 is closed again, so that the filling speed is reduced to a value which corresponds to the filling speed of the filling phase.

8. Relief and based on the pressure of the return gas duct 27

When the level of the liquid filling material in the bottle 11 has reached a level N 'at which the probe 35 responds, the signal from the probe 35 causes the liquid valve 5 to close (possibly after a correction time).

Via the valve 20, which is still open, the pressure in the bottle interior (bottle neck) lying above the level of the liquid filling material is reduced to the pressure in the return gas channel 27, specifically controlled by the throttle 34 ′ assigned to the valve 20. At the pressure level of the return gas duct 27, the liquid filling material in the bottle 11 is degassed and calmed down.

9. Residual relief to atmospheric pressure.

For this purpose, the control valve device 23 is brought into a fifth functional position or switched on, in which the valve 22 is opened, so that via the connecting channel 31, the opened valve 22 and the collecting chamber 28, which is connected to the atmosphere via the line 46, the pressure is relieved to atmospheric pressure.

10. Rinse the neck of the bottle with CO₂ gas.

For this method step, the control valve device 23 is switched to a sixth functional position, which corresponds to the fourth functional position, or else the control valve device 23 is switched back to the fourth functional position, so that the valves 20 and 21 are open. During the withdrawal or lowering of the bottle 11 from the filling element 1, a CO₂ gas flow from the return gas channel 27 is thus established via the opened valve 20 and the throttle 34 'assigned to this valve. The control valve 25 is closed, for example. By opening this control valve, the purge gas flow can be increased by a further component from the gas space 8. By rinsing with CO₂ gas, the area of the bottle 11 or the bottle neck of this bottle lying above the level of the liquid filling material is filled with CO₂ gas, thereby preventing the ingress of air or oxygen.

A special feature of the system described is that the return gas duct 27 has no connection to the atmosphere, at least during operation, while the collecting duct 28 is open to the atmosphere via the line 48.

In Fig. 2, an embodiment is shown, which differs from the embodiment of Fig. 1 essentially only in that the local rotor part, designated 2 ', on which the filling elements 1 are provided, in addition to the ring bowl 7 with gas space 8 and the return gas duct 27 has a vacuum duct 49 which is connected to a vacuum pump 51 via a line 50.

Instead of the control valve device 23, each filling element 1 is assigned a control valve device 23 'which, in addition to the valve functions or valves 17-22, also has a valve function or a valve 52 which, with its upper connection in FIG. 2, has a connecting line 53 with the vacuum channel 49 is connected and with its lower connection in FIG. 2 to the connecting line 30 is connected. Otherwise, the embodiment of FIG. 2 corresponds to the embodiment according to FIG. 1, so that the same reference numerals as in FIG. 1 are used for elements of the same function and design in FIG. 2.

The possible process sequence with the embodiment according to FIG. 2 when filling the respective bottle 11 with the liquid filling material largely corresponds to the process sequence as described above in connection with the embodiment according to FIG. 1. Deviating from the method described above, it is essentially only that the evacuation of the bottle 11 is inserted as an additional method step between the method steps "-2. Pre-rinsing from the return gas channel 27-" and "-3. Partial pre-charging from the return gas channel 27-". For this purpose, the control valve device 23 'is switched to a functional position in which only the additional valve 52 is opened, so that the bottle is formed via the gas duct 15 formed in the gas pipe 9, the space 16, the connecting line 29, the opened valve 52 and the connecting line 53 11 is evacuated. The vacuum or the vacuum in the vacuum chamber 59 and the duration of this process step are selected such that the bottle 11 is pre-evacuated to a vacuum of approximately 90% at the end of this process step.

Before initiating the next process step (partial prestressing from the gas channel 27), the valve 52 is closed again by switching on the control valve device 23 '.

FIG. 3 shows a further embodiment, which differs from the embodiment according to FIG. 1 only in that the connecting line 34 is not connected to the gas space 8 but to the interior 53 of an intermediate container 54. The latter is connected to the gas space 8 via a connecting line 55. A check valve 56 is arranged in the connecting line 55, which allows a gas flow from the gas space 8 into the interior 53, a gas flow into reverse direction but locks. The interior 53 is connected to the return gas duct 27 via a connecting line 57. In the connecting line 57, a control valve 58 is provided to control or regulate the pressure prevailing in the return gas duct 27, which corresponds in function to the control valve 45 and is controlled by a pressure regulator 59, depending on the signal of the pressure in the return gas duct 27 measuring pressure gauge 60.

The possible procedure with the embodiment according to FIG. 3 when filling the respective bottle 11 with the liquid filling material corresponds to the procedure as described above for the embodiment according to FIG. 1. The only difference is that the residual prestressing and during the rapid filling phase do not use the gas space 8, but the interior 53 of the intermediate container 54. The residual prestressing takes place from the interior 53, the pressure of which practically corresponds to the pressure of the gas space 8 (filling pressure). In the rapid filling phase, the additional return gas path acts via the valve 21 and the associated throttle 34 ′ in the interior 53 of the intermediate container 4.

The versions shown in Figures 1 to 3 and the possible methods with these versions has in common that the amount of CO₂ gas, which is taken from the return gas channel 27 during the purging and biasing of the bottles 11, exceeds the amount of CO₂ gas that is returned to the return gas duct 27 during filling. In this respect, a CO₂ gas deficit arises in the return gas duct 27, which is compensated for via the connecting line 44 with the control valve 45.

The supplementation of the CO₂ gas deficit takes place in all of the above-described embodiments by introducing fresh CO₂ gas through the supply line 40. In the embodiments according to FIGS. 1 and 2, the CO₂ gas deficit in the tensioning channel is then via the control valve 45 educated Pressure control compensated directly from the gas space 8. While this compensation takes place in the embodiment according to FIG. 3 via the interior 53 of the collecting container 54.

All embodiments and with these possible procedures is also common that the vast majority of the CO₂ gas used for biasing a bottle 11 when filling in the return gas channel 27 and especially in the gas chamber 8 having the higher gas pressure of the ring bowl 7 or The interior 53 of the intermediate container 54 is returned and can thus be used again for the residual prestressing of a bottle 11 to the higher pressure, with the possibility of a preliminary relief of the bottle 11 after filling and a calming of the liquid filling material in the bottle on a bottom the pre-relief pressure. The designs and systems described thus allow considerable savings in expensive CO₂ gas. 3 also has the additional advantage that the CO₂ gas in the gas space 8 has a particularly high quality or purity, since no return gas can return to this gas space.

The invention has been described above using exemplary embodiments. It goes without saying that changes and modifications are possible without thereby departing from the inventive idea on which the invention is based. For example, in the embodiment shown in FIG. 3, it is possible to connect the interior 53 of the intermediate container 54 directly to the supply line 40, as is shown in FIG. 3 with broken lines at 40 '. In this case, the connection of the supply line 40 to the interior of the boiler 7 or to the gas space 8 is then omitted. Furthermore, the connection line 55 is omitted in this case. The interior of the boiler 7 and in particular also the part of this interior designated “gas space 8” completely filled with the liquid filling material in this embodiment.

Instead of the control of the level N of the product level formed by the control valve 37, the level control 38 and the level meter 39, a pressure control for the filling pressure, ie for the pressure of the product received by the boiler 7, is also provided in this case. From this pressure control also the pressure control 42 receives a control signal via the signal line 61 shown in broken lines in FIG which is lower than the filling pressure by a predetermined amount. This pressure difference between the filling pressure and the pressure in the interior 53 is, for example, 0.1 to 0.2 bar.

List of the reference numbers used

1

Filling element

2, 2 '

Rotor part

3rd

casing

3 '

Housing part

4th

Liquid channel

5

Liquid valve

6

Valve body

7

Ring bowl

8th

Gas space

9

Gas pipe

10th

Outlet opening

11

bottle

12

muzzle

13

Centering tulip

14

poetry

15

Gas path

16

room

17-22

Valve

23, 23 '

Control valve device

24th

Operating lever

25th

Control valve

26

Actuator

27

Return gas duct

28

Collecting channel

29-34

Connecting line

34 '

throttle

35

probe

36

supply line

37

Control valve

38

Level control

39

Level meter

40, 40 '

supply line

41

Control valve

42

Pressure control

43

Pressure gauge

44

Connecting line

45

Control valve

46

Pressure control

47

Pressure gauge

48

management

49

Vacuum channel

50

management

51

Vacuum pump

52

Valve

53

inner space

54

Intermediate container

55

Connecting line

56

check valve

57

Connecting line

58

Control valve

59

Pressure control

60

Pressure gauge

61

management

Claims (19)

Method for filling bottles or the like. Container (11), using a filling element (1) having a liquid valve (5) with a liquid filling material, in which (method) the container (11) in sealing position with the filling element (1) in a pretensioning phase in a first step with a return gas containing inert gas from a return gas channel and in a second step from a further gas channel (8, 53) and in a subsequent filling phase with the liquid filling material (5) open a boiler (7) is filled, at least temporarily the return gas displaced from the incoming filling material from the container (11) is discharged via a gas path of the filling element (1) into the return gas duct (27), characterized in that in the second step Biasing with return gas from the further gas channel (8, 53) takes place that during the filling phase, at least temporarily, that of the incoming F llgut from the container (11) displaced return gas is returned to the other gas channel (8, 53), and that in the return gas channel (27) and the other, directly connected to the return gas channel (27) gas channel (8, 53) inert -Gas is introduced, namely to maintain a predetermined gas pressure. Method according to Claim 1, characterized in that the introduction of the inert gas into the return gas channel (27) takes place via the further gas channel (8, 53). Method according to Claim 1 or 2, characterized in that the return gas displaced from the container (11) during the filling phase is at least temporarily returned to the further gas channel (8, 53) and to the return gas channel (27) at the same time preferably throttled each time. Method according to one of claims 1 to 3, characterized in that a gas space (8) formed in the boiler (7) above the liquid filling material is used as a further gas channel and / or an interior of an intermediate container (54) is used which is connected to the return gas channel (27) and with a gas space (8) formed in the boiler (7) above the liquid filling material. Method according to one of claims 1 to 4, characterized in that during the pretensioning phase, before the pretensioning, the interior of the respective container (11) is purged with the return gas from the return gas duct (27), and / or before the respective container is pretensioned (11) a treatment of this container with a hot sterilization medium, preferably with steam, and / or that the interior of the container is evacuated prior to prestressing. Method according to one of claims 1 to 5, characterized in that in a filling phase at the beginning of the filling phase and / or in a braking and / or correction phase at the end of the filling phase, the return gas is displaced via the gas path into the return gas duct (27). Method according to one of claims 3 to 6, characterized in that in a rapid filling phase of the filling phase, the return gas is displaced both into the return gas channel (27) and into the further gas channel (8, 53). Method according to one of claims 1 to 7, characterized in that the pressure in the return gas channel (27) is adjusted to a value below the pressure of the further gas channel (8, 53) and is kept constant, and / or in that the pressure in the further gas channel ( 8, 53) is maintained at a predetermined, constant value, the pressure in the further gas channel (53) preferably being particularly high when using a boiler (7) completely filled with the liquid filling material constant value relative to the filling pressure or to the pressure of the liquid filling material in the boiler (7) is maintained, preferably at a value below the filling pressure. Device for filling bottles or similar containers (11) with a liquid filling material, with a kettle (7) for holding the filling material, with at least one filling element (1) which is connected to the kettle (7) and has a liquid valve (5) ), as well as with at least one control valve device (23, 23 ') assigned to the filling element (1) and having a plurality of valves, for controlling gas paths formed in the filling element (1) at least during a pretensioning phase in which the sealing element is in sealing position with the filling element (1) The container (11) is pretensioned in a first step with a return gas containing inert gas from a return gas channel (27) and in a second step from a further gas channel (8, 53), and during a subsequent filling phase in which the gas is in the sealing position Containers (11) located with the filling element (1) are filled with the liquid filling material when the liquid valve (5) is open and at least temporarily that of the one Returning gas displaced from the container (11) is discharged into the return gas duct (27), characterized in that the interior of the respective container (11) during the second step of the prestressing and at least temporarily during the second step of the prestressing via the control valve device (23, 23 ') the filling phase can be connected to the further gas channel (8, 53), and that the return gas channel (27) and the further gas channel (8, 53) for maintaining a given gas pressure in each case via an inert gas supply (40, 44, 55, 57) are connected to a source of pure inert gas. Apparatus according to claim 9, characterized in that the inert gas supply to the return gas channel (27) takes place via the further gas channel (8, 53) which is directly connected to the return gas channel (27). Apparatus according to claim 9 or 10, characterized in that the further gas channel is a gas space (8) formed in the interior of the boiler (7) above the level (N) of the product level there, and / or in that the further gas space is from the interior (53 ) an intermediate container (54) is formed. Apparatus according to claim 11, characterized in that the interior (53) of the intermediate container (54) is connected via a flow connection (55, 56) to a gas space (8) formed in the boiler (7) above the level of the filling material there, the flow connection (55, 56) preferably only allows a gas flow in one direction, namely in the direction from the gas space (8) into the interior (53) of the intermediate container (54), and / or that the interior (53) of the intermediate container via a supply line ( 40, 40 ') is connected to the source for pure inert gas, and that a pressure control, preferably a differential pressure control (41, 42, 43, 61) is provided in the supply line, with which the pressure in the interior (53) of the intermediate container (54) relative to the filling pressure or to the pressure of the filling material in the boiler (7) is kept at a constant value, preferably at a value below the filling pressure. Device according to one of claims 9 to 12, characterized in that the further gas space (8, 53) is connected to the return gas duct (27) via means for pressure regulation (45, 46, 47; 58, 59, 60). Device according to one of claims 9 to 13, characterized in that a first gas path including the control valve device (23, 23 ') is provided in the filling element (1), via which the interior of the container (11) during the filling phase at least temporarily with the Return gas duct (27) can be connected. Device according to one of claims 9 to 14, characterized in that a second gas path is provided in the filling element (1) and includes the control valve device (23, 23 '), via which the interior of the container (11) during the filling phase at least temporarily with the Another gas channel (8, 53) can be connected. Device according to one of claims 9 to 15, characterized in that a third gas path is formed in the filling element and includes the control valve device (23, 23 '), via which the interior of the container (11) at least temporarily with the return gas duct (27 ) is connectable, this third gas path preferably being identical to the first gas path. Device according to one of Claims 9 to 16, characterized in that a fourth gas path, which encloses the control valve device (23, 23 '), is formed in the filling element (1), via which the interior of the container (11) for residual prestressing with the further gas channel (8, 53) can be connected, the third gas path preferably being identical to the second gas path. Device according to one of claims 9 to 17, characterized by a vacuum channel (49) and by a fifth gas path formed in the filling element (1) and enclosing the control valve device (23 '), by means of which the interior of the container (11) can be evacuated prior to prestressing is. Device according to one of claims 9 to 18, characterized in that in the second and / or third gas path with the control valve device (23, 23 ') a control valve (25) which can be controlled independently of the control valve device, preferably an electro-pneumatically controllable control valve (25) is provided, the control valve device (23, 23 ') preferably being a control housing which is provided with an actuating element (24) stationary control elements, for example cooperating with control cams or control cams on a stationary control ring.

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