Method and filling system for filling containers

Abstract

A filling method includes executing a pre-stressing phase, during which, at plural time intervals, gas is drawn from a gas space that lies above the filling material in a tank. The gas pre-stresses a container up to a second pressure that is below the pressure in the gas space. During a filling phase, a liquid valve opens to allow the filling material in the tank to enter into the container. This valve is above the level of the filling material, thus preventing gravity from driving the flow.

Claims

1. A method comprising filling a container with a filling material using a filling system in which a closure plane of a liquid valve of a filling element is at a height that is above a filling-material level of in a filling-material container of a mixer, thereby resulting in a height differential, said filling-material container having a gas-filled volume that forms a gas compartment, which is filled with gas at first pressure, said first pressure being a positive gas-compartment pressure, and a liquid-filled volume that is filled with said filling material, said liquid-filled volume forming a liquid compartment, wherein filling said container comprises sealing said container at a sealing position of said filling element, executing a pre-stressing phase, and executing a filling phase, wherein executing said pre-stressing phase comprises, during plural time intervals, using a gas drawn from said gas compartment to pre-stress said container up to a second pressure, said second pressure being a pressure within said container, wherein, upon beginning execution of said filling phase, said second pressure lies below said first pressure and wherein executing said filling phase comprises opening said liquid valve, thereby filling said container with filling material from said liquid compartment via a product line of said filling system and conveying return gas into a collection channel, said return gas having been displaced from said container by said incoming filling material.

2. The method of claim 1, wherein executing said pre-stressing phase further comprises during each of a plurality of intervals, causing said gas to be conveyed away into a ring channel that is at atmospheric pressure.

3. The method of claim 1, wherein executing said pre-stressing phase further comprises regulating flow of said gas into a ring channel so as to control a pressure difference between said first pressure and said second pressure, wherein said ring channel is at atmospheric pressure.

4. The method of claim 1, wherein executing said pre-stressing phase comprises controlling said second pressure such that said second pressure is equal to said first pressure reduced by a sum of third, fourth, and fifth pressures, wherein said third pressure is a negative pressure required to overcome said height differential, wherein said fourth pressure is a negative pressure required to accelerate said filling material from rest to a desired filling speed, and said fifth pressure is a negative pressure required to compensate for the pressure losses incurred by flowing of said filling material.

5. The method of claim 1, wherein executing said filling phase comprises causing return gas to be conveyed away during the entire duration of said filling phase via a flow path into a ring channel and carrying out feedback control to regulate a filling pressure, wherein carrying out said feedback control comprises maintaining a pressure difference between said first pressure and said second pressure, wherein said ring channel is at atmospheric pressure.

6. The method of claim 1, further comprising using feedback control to control said second pressure during said pre-stressing phase and during said filling phase.

7. The method of claim 1, further comprising, during said filling phase, causing sustained conveyance of gas displaced from said container into a ring channel thereby causing a constant gas flow from the gas compartment in the direction of the container being filled and regulating said second pressure during said filling phase to be at a pressure that is below said gas-compartment pressure, wherein said ring channel is at atmospheric pressure.

8. The method of claim 1, further comprising using feedback control to regulate filling speed during said filling phase, wherein using said feedback control comprises, after having opened said liquid valve, using a first control valve to interrupt a fluid connection into a first ring-channel and, immediately thereafter, using a second control valve to open a choked connection into a second ring-channel, wherein said first ring channel carries said pre-stressing gas and wherein said second ring channel is unpressurized.

9. The method of claim 1, further comprising regulating filling speed during said filling phase, wherein regulating said filling speed comprises using a feedback loop that comprises a regulating valve, a flowmeter, and a controller that receives information from said flowmeter and uses said information to control said regulating valve.

10. The method of claim 1, further comprising, after having opened said liquid valve, controlling filling speed by using a regulating valve and a flowmeter.

11. The method of claim 1, further comprising using a feedback loop to exercise feedback control of filling pressure with which said container is filled during said filling phase and a pressure differential between said first and second pressures.

12. The method of claim 1, further comprising exercising feedback control over said first pressure using a pressure-regulating circuit.

13. The method of claim 1, further comprising regulating said first pressure such that said first pressure exceeds carbon-dioxide saturation pressure of said filling material in said liquid compartment.

14. The method of claim 1, further comprising causing flow of filling material into said filling-material container and regulating a level of filling material in said liquid compartment to maintain a constant level.

15. An apparatus for filling containers with liquid filling-material, said apparatus comprising a filling element comprising a filling valve having a closure plane, a filling element arranged at a height above a filling-material level of filling material in a filling-material container of a mixer, said apparatus being configured to seal a container at a sealing position of said filling element, to execute a pre-stressing phase, and to execute a filling phase, wherein executing said pre-stressing phase comprises, during plural time intervals, using a gas drawn from said gas compartment to pre-stress said container up to a pre-stressing pressure, wherein, upon beginning execution of said filling phase, said pre-stressing pressure lies below said positive pressure and wherein executing said filling phase comprises opening said valve, thereby filling said container with filling material from said liquid compartment via a product line of said filling system and conveying return gas into a collection channel, said return gas having been displaced from said container by said incoming filling material.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The invention is described in greater detail hereinafter on the basis of the figures, in which:

(2) FIG. 1 a first embodiment of a filling system,

(3) FIG. 2 shows details of the filling element shown in FIG. 1, and

(4) FIG. 3 shows a second embodiment of the filling system.

(5) Identical reference numbers have been used in the figures for elements which are the same or have the same effect. Moreover, for the sake of easier overview, only reference numbers have been represented in the individual figures which are required for the description of the respective figure. The invention is also only represented in the figures as a schematic view to explain the mode of operation. In particular, the representations in the figures serve only to explain the underlying principle of the invention. For reasons of easier overview, the representation of all the constituent parts of the device has been waived.

DETAILED DESCRIPTION

(6) FIG. 1 shows a filling system 1 for a rotating filling machine that fills liquid filling-material into containers 2, such as bottles or cans, at filling elements 1.1, only one of which is shown in FIG. 1. The filling elements 1.1 are disposed at equal angles around a circumference of a rotor 4 that is driven around a vertical machine-axis MA.

(7) A “mixer” is that part of a beverage-manufacturing system that degasses the base component, which is usually drinking water, and mixes it with a flavoring material, such as a syrup, until the syrup is at an appropriate concentration. If necessary, the beverage-manufacturing system also carbonates the beverage and buffers it with carbon dioxide gas.

(8) The resulting beverage is then stored in a filling-material container 50, which is part of the filling system 1 shown in FIG. 1. The beverage, which is referred to herein as the “filling material,” is then filled into containers 2 using the filling elements 1.1.

(9) The filling-material container 50, which acts as a buffer reservoir or tank for buffering completed beverage, is quite large. A typical volume is as much as a thousand liters. The filling-material container 50 features a gas compartment 50.1 and a liquid compartment 50.2. The gas compartment 50.1 is pressurized with inert gas at a tank pressure P.sub.TANK that exceeds the carbon dioxide saturation beverage in the beverage.

(10) The filling system 1 is configurable for free-jet filling, filling by way of the container wall, and/or long tube filling. In a preferred embodiment, the filling system 1 carries out pressure filling of the bottles 2. During the filling phase in which pressure filling takes place, a container 2 that is being filled is sealed against a filling element 1.1.

(11) A product line 5 filled with the filling material extends along or through the rotor 4 to serve all its filling elements 1.1. Because the product line 5 is filled, there is no gas buffer above the liquid level in the product line 5. In a preferred embodiment, the product line 5 is a ring line.

(12) In addition to the product line 5, the rotor 4 includes first and second ring-channels 30, 40 that, like the product line 5, are common to all the filling elements 1.1 of the filling machine. The first and second ring-channels 30, 40 carry out different functions depending on the filling process. During pressure filling, the first ring-channel 30 acts as a pre-stressing gas channel that conveys inert gas under positive pressure. In some embodiments, the second ring-channel 40 is a return gas or pressure relief channel for relieving the pressure on the containers 2. In such embodiments, the second ring-channel 40 is at atmospheric pressure.

(13) The filling element 1.1 includes a housing 6 in which is formed a liquid channel 7. A liquid valve 9 along this liquid channel 7 controls discharge of filling material into the container 2 through a discharge opening at the filling element's underside. This discharge opening is preferably concentric with a filling-element axis FA and surrounded by a seal 12 against which the bottle's mouth 2.1 is pressed to make a seal during pressure filling. A neck ring holder 11 stabilizes the container 2 during the filling phase.

(14) A connection line 8 connects the liquid channel 7 to the product line 5. A flowmeter 8.1 along the connection line 8 measures volume rate of flow of filling material conveyed by the connection line 8 to the liquid channel 7. In a preferred embodiment, the flowmeter 8.1 is a magnetic-inductive flowmeter.

(15) The liquid valve 9 comprises a valve body 9.1, arranged in the liquid channel 7. The valve body 9.1 interacts with a valve seat formed on an inner surface of the liquid channel 7. The valve body 9.1 and valve seat form a closure plane for the liquid valve 9.

(16) In the illustrated embodiment, the valve body 9.1 is provided at or forms a gas tube 13 that is coaxial with the filling-element axis FA. The gas tube 13, which is open at both ends, serves as a valve plunger for actuating the liquid valve 9. An actuator 14 interacts with the gas tube 13 to cause the valve body 9.1 to move axially along the filling-element axis FA, thereby opening and closing the liquid valve 9.

(17) At its lower end, the gas tube 13 projects through the discharge opening and past the housing's underside. Therefore, during filling, the gas tube 13 extends into the bottle's interior. The tube's upper end extends into a closed gas compartment 15.

(18) A flow path 20 in the filling element 1.1 connects to the bottle's interior via the gas compartment 15 and the gas tube 13. This places the bottle's interior in fluid communication with first and second control valves SV1, SV2 that control fluid communication between the bottle's interior and the first and/or second ring-channels 30, 40.

(19) In some embodiments, the control valves SV1, SV2 have two states, namely “opened” and “closed.” However, in other embodiments, the control valves SV1, SV2 are regulated to be in a multiple states between fully open and fully closed. The flow path 20 carries either gas or liquid. During a pre-stressing phase and/or a filling phase, the flow path 20 is in fluid communication with the bottle's interior.

(20) In a preferred embodiment, the flow path 20 carries an inert gas into the container 2 at a pre-stressing pressure, P.sub.STRESS. This is achieved by connecting the flow path 20 to the first ring-channel 30 using the first control valve SV1.

(21) The flow path 20 also conveys away return gas that is displaced out of the container 2 during the filling phase. This is achieved by connecting the flow path 20 to the second ring-channel 40 using the second control valve SV2. The flow path 20 is thus configurable as a gas path and/or as a gas channel system.

(22) A rotary connection 17 between the rotor 4 and a machine frame provides fluid communication between the second ring-channel 40 and the atmosphere. The first ring-channel 30 and the product line 5 connect via corresponding first and second connecting lines 8.1, 30.1 with the filling-material container 50, which is part of a mixer or mixing system that produces mixed products, such as carbonated beverages.

(23) First and second control valves 30.2, 30.3, both of which are regulatable, are provided in the second connecting line 30.1 for controlling the flow of pre-stressing gas. The first control valve 30.2 forms a fluid-tight connection between the gas compartment 50.1 and the first ring-channel 30 using the second connecting line 30.1. A branch line connects the second connecting line 30.1 to the atmosphere. A third control valve 30.3 along this branch line opens to bring the second connecting line 30.1 to atmospheric pressure.

(24) During pressure filling, the filling system 1 pre-stresses the container with gas drawn from the gas compartment 50.1. This gas is at the positive tank pressure P.sub.TANK.

(25) The filling system 1 comprises a first feedback-loop RK1, or “regulating circuit,” that regulates the pressure in the filling-material container 50. The first feedback-loop RK1 comprises a pressure sensor 52 for detecting the pressure in the gas compartment 50.1, a regulatable control valve 53, and a first controller 54. The first feedback-loop RK1 regulates the gas, which is preferably carbon dioxide, that is conveyed via the gas line 55 into the gas compartment 50.1 from a separate gas source. This gas raises the gas compartment's internal pressure to a positive pressure P.sub.TANK. This positive pressure P.sub.TANK is higher than the carbon dioxide saturation pressure of the mixing product present in the liquid compartment 50.2.

(26) A separate supply line, which has been omitted for clarity, delivers liquid filling-material into the filling-material container 50 in a way that maintains the level of filling material to be constant or close to constant.

(27) The closure plane of the liquid valve 9 of the filling element 1.1 is above the filling material level of the liquid compartment 50.2 of the mixer's filling-material container 50. This results in a negative height difference (H1) between the closure plane of the liquid valve 9 and the filling-material level of the liquid compartment 50.2.

(28) Once the container 2 has been sealed against the filling element, a pre-stressing phase begins. During the pre-stressing phase, the container 2 is pre-stressed at time intervals with gas drawn from the gas compartment 50.1 of the filling-material container 50 of the mixing system. This gas is under the positive pressure P.sub.TANK. During the pre-stressing phase, a pre-stressing pressure P.sub.STRESS is produced in the container 2. This pre-stressing pressure is below the pressure P.sub.TANK of the gas compartment 50.1.

(29) In a subsequent filling phase, the liquid valve 9 opens and filling material from the liquid compartment 50.2 of the mixer's filling-material container 50 passes through the connection line 8, which becomes completely filled with the fluid filling material. This filling material enters the container 2 and displaces gas that is already in the container 2. The incoming filling material is drives this gas into the return gas path 20 of the filling element 1.1 and into the second ring-channel 40, which serves as a return gas channel.

(30) The filling system 1 includes a second feedback-loop RK2 for regulating the pre-stressing pressure. The second feedback-loop RK2 includes first and second control valves 30.2, 30.3, a first sensor 56.1 and/or a second sensor 56.2 for detecting a filling pressure, and a third sensor 56.3 along the connecting line 30.1 between the second control valve 30.3 and the first ring-channel 30, for detecting the pre-stressing gas pressure. A second controller 57 controls operation of the control valves 30.2, 30.3 based on information provided by the sensors 56.1, 56.2, 56.3. During the pre-stressing phase, the second feedback-loop RK2 causes the pre-stressing pressure within the container 2 to be at a value P.sub.STRESS that is less than the positive pressure P.sub.TANK of the gas compartment 50.1.

(31) In some practices, during the pre-stressing phase, there exist discrete time intervals during each of which a bolus of pre-stressing gas is conveyed away into the second ring-channel 40, which is under atmospheric pressure. In other practices, the pre-stressing gas is released during the entire duration of the pre-stressing phase into the second ring-channel 40.

(32) In either case, the pre-stressing gas is conveyed away via the flow path 20 into the second ring-channel 40 in a controlled and/or regulated manner in such a way that an adjustable pressure difference DP is produced between the positive pressure P.sub.TANK of the gas compartment 50.1 and the pre-stressing pressure P.sub.STRESS in the container 2 during the pre-stressing phase. This pressure difference DF is regulated and/or controlled by the second feedback-loop RK2. In such cases, the pressure difference DF between the positive pressure P.sub.TANK of the gas compartment 50.1 and the pre-stressing pressure P.sub.STRESS in the container 2 is a reference pressure that the second controller 57 attempts to maintain using the second feedback-loop RK2.

(33) The first and/or second sensors 56.1, 56.2 measure actual values of pressure. The second controller 57 interpolates these measured values toto regulate the pre-stressing pressure P.sub.STRESS, which is given by the following relationship:
P.sub.STRESS=P.sub.TANK—P.sub.ΔH1—P.sub.FILLINGSPEED—P.sub.FLOWLOSS

(34) In the foregoing relationship, P.sub.TANK is the positive pressure in the gas compartment 50.1, P.sub.ΔH1 is the negative pressure required to overcome the height differential H1, P.sub.FILLINGSPEED is a calculated negative pressure that would be required to accelerate filling material at rest up to the desired filling speed, and P.sub.FLOWLOSS corresponds to negative pressure required to compensate for the pressure losses incurred by the flow of the filling material. Since the filling capacity determines the flow speed of the filling material, and therefore also the flow losses, the flow losses are constantly changing.

(35) To compensate for rapid changes in any of the foregoing parameters, the second feedback-loop RK2 engages in equally rapid dynamic guidance in an effort to maintain the pre-stress pressure at the correct value notwithstanding variations in those parameters. Of the parameters given, flow loss is typically the one that varies rapidly. A typical time interval for a dynamic adjustment of the guidance value of the second feedback-loop RK2 lies in the range between ten milliseconds and five hundred milliseconds. In a preferred embodiment, the second controller 57 makes necessary adjustments at intervals of between twenty milliseconds and two hundred milliseconds. In the course of this procedure, gas flows through the first and/or second control valves SV1, SV2 at a rate that corresponds to a filling speed of between fifty and four hundred meters per second.

(36) In some embodiments, the second feedback-loop RK also regulates the filling pressure during the filling phase after the containers have been pre-stressed during the pre-stressing phase using gas drawn from the gas compartment 50.1. In this embodiment, any pre-stressing gas that remains in the container 2 as a result of the pre-stressing phase is displaced by the filling material that enters the container and is thus conveyed out of the container 2 via the flow path 20 into the second ring-channel 40, preferably during the entire duration of the filling phase. In this case, the second feedback-loop RK controls the pressure difference DF between the positive pressure P.sub.TANK and the pre-stressing pressure P.sub.STRESS.

(37) Preferably, the second feedback-loop RK regulates the pressure difference DF to attain a filling speed that corresponds to that which would have resulted from a water column of between three hundred and a thousand millimeters. This would correspond to a pressure of between 0.03 bar and 0.1 bar. The second feedback-loop RK2 thus maintains the pressure difference DF both during the pre-stressing phase and during the subsequent filling phase.

(38) The second feedback-loop RK2, by controlling the pressure difference DF during the filling phase in the container 2, allows an inflow of the filling material into the container 2 and controls the filling speed into the container 2. The second feedback-loop RK2 thus adjusts the maximum possible filling speed during the filling phase.

(39) In such embodiments, opening of the liquid valve 9 is followed by using the first control valve SV1 to close the gas connection into the first ring-channel 30, which in this case carries pre-stressing gas. Immediately thereafter, the second control valve SV2 forms a choked connection into the unpressurized return gas channel 40. The size of the choke opening formed by the second control valve SV2 controls outflowing gas quantity and therefore the filling speed using the second feedback-loop RK2. To provide two filling speeds required, it is useful to have two control valves SV1, SV2 with different choke sizes. The pressure relief after the end of the filling phase is then caused by the same choked gas path as that used during the filling phase.

(40) An alternative embodiment, shown in FIG. 3, features a third feedback loop RK3 that includes a regulating valve 41, a flowmeter 8.1, and a third controller 42. In this embodiment, the regulating valve 41 is one that is continuously adjustable and can therefore assume any intermediate position between being open and being closed. In some embodiments, the controller 42 is configured to designate intermediate settings as a stationary settings and to transition between them, thus causing the feedback loop RK3 to have a discrete rather than continuous manipulated variable.

(41) The regulating valve 41 is installed in the connection line 8 of the product line 5 to the flowmeter 8.1, and specifically between the product line 5 and the flowmeter 8.1. The regulating valve 41 therefore forms, together with the flowmeter 8.1, the third regulating circuit RK3 for regulating and/or controlling the filling speed during the filling element's filling phase. After the pre-stressing, the pressure difference DZ prevails in the respective container 2. This is sufficient to ensure a flow in the direction of the container 2. By controlling the regulating valve 41 based on information from the flowmeter 8.1, it is possible for the third feedback loop RK3 to control the filling speed after the liquid valve 9 has been opened. In this embodiment, return gas can then flow back again into the ring channel and be made available for reuse when filling the next container 2.

(42) In some embodiments, during the filling phase, the second feedback-loop RK2 produces a sustained flow of the return gas into the second ring-channel 40. This results in a constant flow of gas out of the gas compartment 50.1. This permits regulation of pressure in the container 50 during the filling phase so that it remains below the positive pressure P.sub.TANK of the gas compartment 50.1.

(43) In other embodiments, the second feedback-loop RK2 provides a way to control the filling pressure used when filling the container 2 during the filling phase and to adjust the pressure difference DF produced during the prestressing phase to achieve the prestressing pressure P.sub.STRESS.

(44) The invention has been described heretofore by way of exemplary embodiments. It is understood that numerous modifications and derivations are possible, without thereby departing from the inventive concept underlying the invention.

(45) In some embodiments, the product line 5 to only almost completely filled with the fluid filling material so that some gas is present therein. However, this is undesirable because gas is highly compressible. As a result, its volume may change significantly during pressure fluctuations. This would tend to have a negative effect on the filling process. It is therefore important for any such gas volume to be so small that the effect on the filling process will be negligible. For this to be the case, the volume of any such gas should be substantially smaller than that of the product line 5.