GB2116530A - Method of and apparatus for filling of containers with liquid - Google Patents

Abstract

A method of filling liquid, for example a beverage containing carbon dioxide, into a closed container such as a keg with filling and tap fittings, is carried out in three filling phases, namely a starting, a rapid filling and a complete filling phase. The volume to be filled during each phase is measured in throughflow and the next phase is initiated as soon as a predetermined target volume of the previous phase has been reached. Serving for this are an inductive throughflow meter (9), an electronic evaluating system (11) with settable target volume values, and multi-stage valve equipment (18, 21). Overfilling of the container is thereby avoided. <IMAGE>

Description

SPECIFICATION Method of and apparatus for filling containers with liquid The present invention relates to a method of and apparatus for filling containers, such as barrellike containers or kegs closed by filling and tap fittings (connection fittings), with liquid, for example a beverage containing carbon dioxide, and has particular reference to counterpressure failing of gas-liquid containers with simultaneous expulsion of the gas through a vent, for example the connection fitting.

Kegs, which are closed off by connection fittings, which are frequently called filling and tap fittings, are mainly used for the transport of beer.

They offer appreciable advantages compared with conventional barrels, because the interior of the keg remains closed by the connection fitting and therefore generally foreign substances cannot get into the keg. Moreover, a completely automatic treatment, i.e. cleaning, sterilising and filling, is made possible.

The filling of the kegs with beer usually takes place from below the liquid surface by way of a downwardly pointed connection fitting, so that the liquid flows in through a carbon dioxide valve of the connection fitting and a displaced counterpressure gas flows away downwardly from the top through a stand pipe. When the beer finally runs over the upper rim of the stand pipe, the keg is filled completely. The overflowing beer thus escapes from the interior of the keg. The filling operation, based on this overflow of beer, can now be terminated in a desired manner, floats, pressure pulse sensors and conductivity meters, for example, being used in known keg filling machines.

It is known that kegs, which are produced from fine steel, are composed of a particularly thinwalled material and in some circumstances a volume enlargement of a keg can occur if, for example, on a hot day, a completely filled keg is strongly heated. The liquid then expands and the keg is thereby irreversibly stretched with reduction of its usual corrugations. Such a keg is necessarily overfilled during the next filling operation and kegs of that kind cause appreciable losses of beer. The cause for this is the overfilling of the kegs, because it is necessary to wait until beer overflows from the keg. Any form of probe reaching into the keg for a timed termination of the filling operation cannot be used in view of the connection fitting and-associated valve equipments.

In order, if possible to avoid these disadvantages, measuring devices, for example rotary piston counters or turbine wheel counters, have been used, through which the kegs are filled with the envisaged beer volume. As soon as the keg has been filled with this volume, the further inflow of beer into the keg is stopped. However, during inflow the beer is subjected to turbulence and foaming so that preliminary foam issues from the keg and thus impairs the measurement result and the desired filling accuracy. In addition, inaccuracies and measurement errors occur due to wear of moving parts and to stressing and influencing of the material during cleaning and sterilising of these measuring devices.

There is accordingly a need for a method of and apparatus for low turbulence, low foam and consistently accurate measured filling of liquids, such as beer or other beverages containing carbon dioxide, into kegs or other containers without prolongation of the filling time.

According to a first aspect of the present invention there is provided a method of counterpressure filling of a gas-filled closed container with liquid with simultaneous expulsion of the gas through a vent, the method comprising the steps of metering and conducting a first predetermined volume of the liquid into the container in a first, slow filling phase, metering and conducting a second predetermined volume of the liquid into the container in a second, fast filling phase with a filling rate faster than that in the first filling phase, and metering and conducting a third predetermined volume of the liquid into the container in a third, slow filling phase with a filling rate slower than that in the second filling phase, the total of the first, second and third volumes corresponding to a target filling volume for the container.

In a preferred example of the method, the liquid volume conducted to the container is measured by means of a measuring device in terms of a filling volume target value provided for the container, a first predetermined partial volume of liquid is measured and then slowly introduced into the container during the first and starting phase, a second predetermined partial volume of liquid is measured and then rapidly introduced into the container during the second and rapid filling phase, and a third predetermined partial volume of liquid is measured and then slowly introduced into the container during the third and complete filling phase, the sum of the three partial volumes of liquid corresponding to the filling volume target value provided for the respective container.

Thus, in this example a slow filling of a first, exactly predetermined and measured volume of liquid, such as beer, takes place initially, whereby foaming and turbulence are avoided. The smooth start thus effected now permits a particularly rapid filling of the next measured, usually largest, volume proportion. The inflow of the liquid is not stopped abruptly, which could lead to disturbance of the liquid and to inaccuracies in filling, but the slow final filling follows with the last measured volume proportion. Thereby a slow and accurate final filling can be achieved without flow of the liquid over, for example, the top of a stand pipe in the container for venting of the gas.Moreover, the container is not overfilled with consequent loss of the liquid and, in the case of construction of the container from deformable material, such as Niromaterial, this material is not overstretched and a permanent volume enlargement of the container is thus avoided.

For preference, the three partial volumes of liquid are fed continuously and in sequence into the container.

The inflow of the measured quantities of liquid takes place without transition in the three phases so that an interruption of the inflow and thereby delays and turbulence are avoided.

It is furthermore proposed that the respective target values of the three partial volumes of liquid may be predetermined before the filling operation according to the size of the container and the mode of construction of connection fittings thereof. The respective target values of the partial volumes are thus preset by taking account of the container size, namely its diameter as well as its height. Moreover, the amount of liquid to be filled during the first phase must be such that the or each inflow opening of the connection fitting is completely covered by the filled liquid. Such openings, for example slots, may be of different heights in different connection fittings, so that different volumes of liquid may need to be filled during the first phase even for containers with the same diameter.The dimensions of the container are also critical for the other volumes to be introduced into the container.

For preference, the speed of the liquid conducted into the container is measured inductively and the volume of liquid put through since the start of filling as well as the three partial volume of liquid are picked up digitally, the instantaneous volume flow in the rapid filling phase being increased relative to the starting phase and the instantaneous volume flow in the complete filling phase being reduced relative to the rapid filling phase in that case. Due to the inductive detection, mechanical counting devices can be dispensed with. As a result, any pressure drop in and disturbance of the liquid to be filled are avoided. The on-going digital detection of the measurement values permits an accurate control of the inflow of the three measured volumes of liquid.

According to a second aspect of the present invention there is provided apparatus for carrying out the method according to the first aspect of the invention, the apparatus comprising duct means to conduct liquid for filling such container, measuring means to measure the throughflow of liquid in the duct means at a measuring point therein and to provide a signal indicative of the measured throughflow, multi-stage valve means arranged in the duct means downstream of the measuring point and controllable to provide different rates of flow through the duct means, and electronic control means to so control the valve means in dependence on the measured throughflow as to cause a first flow stage of the valve means to be open by itself for performance of the first filling phase until the measured throughflow volume has reached a first predetermined value, thereafter a second flow stage of the valve means to be open together with the first flow stage for performance of the second filling phase until the measured throughflow volume has reached a second predetermined value, and thereafter any one of the first flow stage, the second flow stage, and a third flow stage of the valve means to be open by itself for performance of the third filling phase until the measured throughflow volume has reached a third predetermined value.

In a preferred embodiment of such apparatus, an inductive throughflow measurement value transmitter is arranged in a liquid feed duct to a connection fitting of the container and a valve device, which is switchable in steps, is arranged in the duct between the transmitter and the connection fitting. A measurement voltage line is led from the transmitter to a digital evaluating and switching electronic system and control lines are led from this system to the valve device.The digital evaluating and switching electronic system comprises at least three measurement value indicators, logically interlinked one with the other in the manner of a sequence control circuit and set to "litres of throughflow volume of liquid" and each with a separate target value input, in such a manner that a first throughflow stage is opened up to the attainment of a first target value, a second throughflow stage is opened in addition up to the attainment of the second target value, and again only the first throughflow stage is opened up to the attainment of a third target value.

Apparatus according to this embodiment permits an initial setting of the respective target values of the individual partial volumes which are to be introduced into the container as well as the control of the addition of the partial volumes with differently sized volume flow. In that case, a single valve, which is controllable to open and shut in several stages, can be provided in the feed duct to the connection fitting. Alternatively, individually remotely controllable valves, in branches with differently dimensioned flow cross-sections, can be used. If the volume flow of the starting phase is exactly the same as the volume flow in the final filling phase, two switching stages suffice and, in consequence thereof, two valves or two opening stages of one valve.If the complete filling phase is to have a volume flow which differs from the volume flow in the starting phase, more than three measurement value indicators, and valve means with more than two valves, can be provided in appropriate manner.

An example of the method and an embodiment of the apparatus of the invention will now be more particularly described with reference to the accompanying drawings, in which: Fig. 1 is a circuit diagram of apparatus embodying the invention, suitable for performance of a method exemplifying the invention; Fig. 2 is a schematic partly sectional view of a keg with connection fitting and filling head: and Fig. 3 is a front view of measurement value indicators on a front plate of the apparatus.

Referring now to the drawings, there is shown in Fig. 2 a liquid feed duct 1 leading to a filling head 2, which is arranged at a stationary location in a treatment machine (not shown) and which is shown only schematically, with omission of all liquid and gas valves. The filling head 2 has a liquid stub pipe 4 for the connection of the liquid duct and a counterpressure gas stub pipe 5. Both stub pipes 4 and 5 are used in this manner only during cleaning and filling, but not during tapping of a connected keg 6. The filling head 2 is connected to a connection fitting 3 of the keg, the fitting 3 being firmly arranged at the keg and extending with a stand pipe 7 as far as an upper wall 8 of the keg.

As shown in Fig. 1, an inductive measurement value transmitter 9 is arranged around the liquid duct 1 and connected by a measurement voltage line 10 to an electronic evaluating and switching system 11. Within this system 11 the measurement voltage is digitalised in a measurement value translator 12 and fed through a line 1 Oa to a measurement value indicator 13, calibrated in litres, for the total volume of the keg, the indicator 1 3 having a setter 1 5a for presetting a desired total volume. From there, the measurement value pulses pass through a pulse line 14 to a measurement value indicator 15, calibrated in litres, for a starting volume, the desired volume of which can be predetermined as a target value by a target value setter 1 5a.

Branching from the pulse line 14 is a pulse line 16, which leads to a switch 1 7 of an electromagnetic valve 1 8. Immediately on arrival of a first pulse through the pulse line 14, the measurement value indicator 1 5 is set into motion and the valve 18, which controls the flow passage in a narrow branch duct 19 of the duct 1, is opened by way of the line 16, the switch 17 and a control line 30. At this stage, a wider cross-section parallel branch duct 20, which is controlled by an electromagnetic valve 21, remains closed by the valve 21.Only after the volume indicated on the indicator 1 5 has reached the preset target value, this target value being illustrated in dashed lines schematically, is each further arriving pulse passed on through the indicator 1 5 directly through a pulse line 22. The first of these pulses is then transmitted to a measurement value indicator 23 as well as to a switch 24 whereby, in addition to the valve 18, the valve 21 is now opened through a control line 31 and a particularly large flow is conducted through the duct 1 to the filling head 2.The target value for the second filling phase - the rapid filling phase - is also manually presettable by a setter 23a at the indicator 23 and, as soon as this target value is reached, all further measurement pulses are conducted through a pulse line 25, namely to a measurement value indicator 26 for the complete filling volume and through a branch line to the switch 24, which then brings the valve 21 into closed setting through the control line 31.

As a result, liquid is conducted to the keg again only through the narrow branch duct 1 9 during the complete filling phase, for which the measurement value indicator 26 is relevant. The filling operation is correspondingly slow and the complete filling takes place free of turbulence and foaming, the filling operation being terminated without overrun or overflow as soon as the target volume, preset in the indicator 26 by a setter 26a, for the complete filling is reached. Then, valve 1 8 and the branch duct 19 are closed through the pulse line 27, the switch 1 7 and the control line 30. The volumes required for the filling phases can be preset manually by the target value setters 13a, 15a, 23a and 26a.Additional throttle valves 28 and 29, by which the instantaneous volume flow in both the ducts is variable, can be provided in the branches 19 and 20. Thus, the filling time of the keg 6 and the duration of the individual filling phase can be influenced through these throttle valves 28 and 29 independently of the determined throughflow volumes of the individual phases.

The connection fitting 3 has inflow openings 32 through which the liquid supplied through the duct 1 enters the keg 6. A counterpressure gas, which is displaced by inflowing liquid, flows in direction of the arrow 36 out of the stub pipe 5. In the starting phase of the filling, such an amount of liquid is supplied relatively slowly through the duct 1 and the stub pipe 4 and out of the openings 32 that the openings are completely submerged by the liquid, as the indicated liquid surface level 33 shows. In the rapid filling phase, following relatively rapidly, the quantity of liquid supplied through the openings 32 is such that the liquid surface height 34 is reached.Then liquid is added again relatively slowly up to the surface height 35, the envisaged end volume, so that a true-tomeasure, largely foaming- and turbulence-free filling of the keg is achieved without liquid or foam passing over the top of the stand pipe 7 and issuing downwardly through the stub pipe 5. A measurement accuracy of +0.2% has been shown to be achievable by the inductive throughflow measurement in conjunction with the electronically controlled 3-stage, volumetric liquid measurement. In that case, there exists a substantial degree of independence from the density, the temperature and the conductivity of the liquid, which are of significant importance in the case of known filling methods.

In place of the two valves 18 and 21 in the ducts 1 9 and 20, a single, multi-stage electromagnetic valve can be provided in the duct 1. The switch 1 7 then actuates the first, smaller flow cross-section stage of the multi-stage valve, while the switch 24 controls the second, larger flow cross-section stage. The electronic system 11 has been illustrated schematically and described only to the extent necessary for an understanding of the function, and other electronic systems can be used. One possible arrangement of the measurement value indicators 13,15,23 and 26 of the system 11 is illustrated in Fig. 3. The measurement value transmitter, measurement value indicators and the electronic system can be combined in a common housing to provide a compact instrument.

Claims (13)

1. A method of counterpressure filling of a gasfilled closed container with liquid with simultaneous expulsion of the gas through a vent, the method comprising the steps of metering and conducting a first predetermined volume of the liquid into the container in a first, slow filling phase, metering and conducting a second predetermined volume of the liquid into the container in a second, fast filling phase with a filling rate faster than that in the first filling phase, and metering and conducting a third predetermined volume of the liquid into the container in a third, slow filling phase with a filling rate slower than that in the second filling phase, the total of the first, second and third volumes corresponding to a target filling volume for the container.

2. A method as claimed in claim 1, wherein the steps of metering and conducting the liquid into the container in the first, second and third filling phases are carried out in a continuous sequence.

3. A method as claimed in either claim 1 or claim 2, comprising the step, prior to the steps of metering and conducting, of determining the first, second and third volumes as a function of the volume of the container and the height of liquid inlet port means of the container.

4. A method as claimed in any one of the preceding claims, comprising the additional steps of measuring the speed of flow of liquid to the container by measuring means and digitally indicating each of the three predetermined volumes and the total volume of liquid that has passed the measuring means since the start of the filling phases, the liquid flow rate being higher in the second filling phase than that in the first filling phase and lower in the third filling phase than that in the second filling phase.

5. A method substantially as hereinbefore described with reference to the accompanying drawings.

6. Apparatus for carrying out the method claimed in claim 1, comprising duct means to conduct liquid for filling such container, measuring means to measure the throughflow of liquid in the duct means at a measuring point therein and to provide a signal indicative of the measured throughflow, multi-stage valve means arranged in the duct means downstream of the measuring point and controllable to provide different rates of flow through the duct means, and electronic control means to so control the valve means in dependence on the measured throughflow as to cause a first flow stage of the valve means to be open by itself for performance of the first filling phase until the measured throughflow volume has reached a first predetermined value, thereafter a second flow stage of the valve means to be open together with the first flow stage for performance of the second filling phase until the measured throughflow volume has reached a second predetermined value, and thereafter any one of the first flow stage, the second flow stage, and a third flow stage of the valve means to be open by itself for performance of the third filling phase until the measured throughflow volume has reached a third predetermined value.

7. Apparatus as claimed in claim 6, the control means comprising three sequentially interlinked control elements each actuable at the instant of attainment of a respective one of the predetermined values to transmit a control signal for control of the valve means.

8. Apparatus as claimed in claim 7, wherein each of the control elements comprises means for varying the instant of actuation thereof and thus the respective predetermined value.

9. Apparatus as claimed in either claim 7 or claim 8, wherein each of the control elements comprises means for indicating the respective predetermined value.

10. Apparatus as claimed in any one of claims 6 to 9, the control means being adapted to digitally process the measuring means signal.

11. Apparatus as claimed in any one of claims 6 to 10, the measuring means comprising an inductance measuring device providing a signal voltage indicative of the measured throughflow.

12. Apparatus as claimed in any one of claims 6 to 11, the valve means comprising an electromagnetically actuable valve element movable between two opening positions corresponding to, respectively, the first flow stage and the first and second flow stage together.

13. Apparatus as claimed in any one of claims 6 to 11 , the valve means comprising two separately controllable valves arranged one in each of two branches of the duct means, the branches being of respectively different flow cross-sections and merging together downstream of the valves.

1 4. Apparatus substantially as hereinbefore described with reference to the accompanying drawings.