BACKGROUND ART Apparatus of this type are used for filling containers, such as bags, with a predetermined weight of flowable material such as, for example cereals, grains or rice.

An example of the applicant's prior apparatus of this type is shown in Australian patent No. 551762. This apparatus includes a chute which toggles under the influence of counterweights between directing all the flowable material input stream to a first container or to a second container.

A disadvantage of this prior art apparatus is that the speed of the flowable material must be limited so that the weighing apparatus can terminate the flow of material entering a container upon reaching its predetermined weight, with reasonable accuracy, notwithstanding inflight material and flow rate variations.

It is an object of the present invention to substantially overcome or at least ameliorate the disadvantages of the prior art devices and more particularly to provide a faster and more efficient filling arrangement.

DISCLOSURE OF THE INVENTION Accordingly, in a first aspect, the present invention provides an apparatus for filling a plurality of containers with flowable material, the apparatus including a movable material guide which receives an input of flowable material, the movable guide being adapted to be selectively moved between:

a first end position in which all the flowable material input is guided to a first container; an intermediate position in which the flowable material input is divided between the first container and a second container; and a second end position in which the flowable material input is guided to the second container.

The apparatus is preferably configured to continuously sequentially fill the first and second containers and further containers substituted therefor until a predetermined number of containers is filled or the material input is exhausted.

Preferably, the portion of flowable material input directed to the first container increases as the movable material guide nears the first container and vice-versa.

Desirably, when the material guide is half way between the two end positions the material input is split substantially equally between the two containers.

In a preferred embodiment, the material guide is a chute adapted to pivot about a substantially vertical axis between the two end positions. The chute preferably includes an inclined base and two substantially vertical side walls. The base is preferably upwardly convex and includes corrugations for spreading the material flow across the width of the base.

In other embodiments, the material guide is a vibrating tray, or an auger fed nozzle which pivots in a substantially horizontal plane, or a gravity fed nozzle mounted beneath a flexible tube for pivoting in a substantially vertical plane.

The apparatus preferably includes weighing devices to weigh the amount of material in each of the containers. The apparatus preferably also includes a control system adapted to cause moving of the material guide between the first end, intermediate and second end positions. In a sophisticated version of the invention, the control system causes such movement in response to the weight of material in each of the containers.

The control system may be pneumatically driven. It also preferably includes fine adjustment means capable of adjusting the portion of flowable material input into the first or second container to a fine degree. For example, in one embodiment, the fine adjustment may cause the input to be divided so that 99% flows into one container while 1% flows into the other.

The fine adjustment means preferably takes the form of a wheel adapted to cause the chute to move in small increments towards the first or second container.

In a second aspect, the present invention provides a method for filling a plurality of containers, said method including the steps of: (1) directing all of an input of flowable material into a first container until it is filled to a first predetermined weight; (2) directing a portion of the flowable material input into each of the first container and a second container until the first container is substantially full; (3) directing all of the flowable material input into the second container until it is filled to a second predetermined weight; (4) replacing the first container with a third container; (5) directing a portion of the flowable material input into each of the third and second containers until the second container is substantially full; and (6) replacing the second container with a fourth container.

Preferably, steps (1) to (6) are repeated to continuously fill a plurality of containers until a predetermined number of containers is filled or the flowable material input is exhausted.

The first and second predetermined weights are preferably substantially equal.

Desirably, the flow at step (2) is directed 10% to the first container and 90% to the second container. At step (5) the flow is desirably directed 90%, 10% to the third and second containers respectively.

BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Fig. 1 is a side view of a filling apparatus according to a first embodiment of the invention with the material guide in the first end positions; Fig. 2 is a front view of the apparatus shown in Fig. 1; Fig. 3 is a side view of the apparatus shown in Fig. 1 with the material guide at an intermediate position between the first and second end positions; Fig. 4 is a front view of the apparatus shown in Fig. 3; Fig. 5 is a side view of the apparatus shown in Fig. 1 with the material guide in the second end position; Fig. 6 is a front view of the apparatus shown in Fig. 5; Fig. 7 is a perspective view of a material guide chute; Fig. 8 is a partial end view of the chute of Fig. 7 along line 8-8; Fig. 9 is a schematic view of a pneumatic circuit used to control the position of the chute shown in Figs. 1 to 7; Fig. 10 is a perspective view of the load cell arrangement of the apparatus shown in Fig. 1; Fig. 11 is a perspective view of a filling apparatus according to a second embodiment of the invention;

Figs. 12a to 12f are plan views of the apparatus of Fig. 11 with the material guide in various filling positions; Fig. 13 is a perspective view of a filling apparatus according to a third embodiment of the invention; Fig. 14 is a perspective view of a filling apparatus according to a fourth embodiment of the invention; and Fig. 15 is a cross-sectional side view of the auger of the embodiment of Fig. 14.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to Figs. 1 to 6, there is shown a first embodiment of an apparatus 10 for filling a first container 12 and a second container 14 with flowable material leaving the outlet 15 of, for example, an overhead hopper gravity feeding through a pneumatic gate valve, an auger driven by a variable speed electric motor or a vibratory feeder.

The apparatus 10 includes a movable material guide in the form of chute 16 which has a generally U-shaped cross section. The chute is best seen in Figs. 7 and 8 and includes an inclined upwardly convex corrugated base 18 between two side walls 20. The corrugations and convexity of the base 18 facilitate spreading of the flowable material evenly across the width of the base 18. The chute 16 is mounted at the top of a shaft 22 which is rotatable about a vertical axis 24.

Each of the containers 12 and 14 is releasably mounted to respective weighing and bagging devices 26 and 28 respectively. Above each of the weighing and bagging devices 26 and 28 there is a pair of respective fixed material guides 30 and 32. The guides 30 and 32 are attached to each other along a vertical edge 34 which is at the apex of two inner inclined side walls 36 and 38 respectively.

The chute 16 and the guides 30 and 32 are desirably manufactured from stainless steel for ease of cleaning and corrosion resistance.

The chute 16 is adapted to be movable between a first end position in which it directs all of the material input from the hopper through the first fixed guide 30 and into the first container 12, as shown in Fig. 2, and a second end position in which it directs all of the material through the second fixed guide 32 into the second container 14, as shown in Fig 6. At intermediate positions between the two end positions, the flowable material input is incident on the edge 34 and is partially directed through both the fixed guides 30 and 32 and thus divided between the first and second containers 12 and 14 respectively, as shown in Fig. 4.

As Fig. 4 approximately indicates, the closer the chute 16 is to an end position, the greater proportion of the total available material flow is directed to the adjacent container 12 or 14. This allows a very slow flow rate of material to be directed into a container which is nearly full for accurate final filling and weighing off whist the larger remaining flow of material can be simultaneously filling another container, thereby increasing accuracy and reducing overall filling times.

As an example, the apparatus 10 can be configured such that the chute 16 will initially direct all of the material flow to the first container 12 until the weighing and bagging device 26 indicates that the container 12 is approximately 85% full.

At this point, the chute 16 is pivoted towards the second end position to an intermediate position above the edge 34 where 10% of the overall material flow continues to fill the first container 12 and the remaining 90% of the flow commences to fill the second container 14. When the first container 12 is 100% full, the chute 16 is moved to the second end position and directs all of the material flow to the second container 14. As the second container reaches 85% full, the chute 16 is pivoted to another intermediate position directing 10% of the flow to the second container 14 and the remaining 90% to a new and empty first container 12.

The chute 16 is continuously moved between end-intermediate-end positions until a predetermined number of containers has been filled or the material flow is exhausted.

Another example will now be described with reference to pneumatic circuit 48 shown in Fig. 9 and the weighing and bagging devices 26,28 shown in Fig. 10.

Fig. 9 shows a pivotable link 40 which is attached to the shaft 22 such that movement of end 42 of link 40 causes the link 40 to pivot about axis 24 and thereby pivot the chute 16 between the end-intermediate-end positions. The weighing and bagging devices 26 and 28 each includes an air switch (not shown) to sense whether or not a container 12,14 has been mounted in respect thereto.

The circuit 48 also includes flow control valves 44 and 46, air cylinders 50,52,54 and 56 and control valves 58,60,62,64,66 and 68 which are all controlled by a Programmable Logic Controller (PLC) (not shown).

While air cylinders 50,52,54 and 56 will cause link 40 to pivot about axis 24 in order to pivot chute 16 to an end position or an intermediate position, adjustment mechanisms 108 and 110 (refer also Fig. 11) can provide fine adjustment of the flow from chute 16 into container 12 or 14. For example, rotation of wheel 112 or 114 will enable arm 116 or 118 respectively to make small adjustments in movement of end 42 of link 40, thus making fine adjustments in the position of chute 16. In this way, in some embodiments of the invention, it is possible to direct a very small proportion, say 10g, of the flow from chute 16 into container 12 and the rest of the flow into container 14.

Fig. 10 shows one of the weighing and bagging devices 26,28, each of which includes a filling head 41 to which one of the container 12,14 respectively, such as a bag, may be clamped. A flexible shroud 43 ensures material leaving the fixed guides 30,32 does not spill whilst entering the filling head 41.

Each of the filling heads 41 extends horizontally at right angles from a beam 45 which is mounted to the chassis of the apparatus 10 by two load cells 47A, 47B.

The signals generated by each pair of the load cells 47A, 47B are calibrated to indicate the weight in each of the container 12,14 in one of the respective pair of displays 49.

The circuit 48 receives control signals from the PLC in response to signals issued by the displays 49 through lines 51 indicating their respective container are, for example, 70%, 85% or 100% of the total predetermined desired"full"container weight (known as set points one, two and three respectively). The displays 49 can be manually reset to provide other weight set-points.

As seen in Figs. 10 and 11, when the apparatus 10 is activated, power is supplied to the weighing units 26 and 28 and the cylinders 50 and 52 are retracted. The PLC then checks the state of the associated air valve to sense if a container 12 is clamped to the weighing device 26. If the container 12 is sensed to be present, the PLC energises the mechanism supplying the outlet 15 with flowable material, for example, an auger driven by a variable speed electric motor, and drives the motor at a speed inducing material flow at its highest possible rate. The chute 16 is in the first end position of Fig. 2 and directs all of the material flow into the first container 12. If the container 12 is not sensed to be present, the motor is not energised.

At set point one, the PLC checks to see if the other air valve is indicating whether the second container 14 is present at the second weighing and bagging device 28. If the container 14 is not present, the material flow is stoppe. If the container 14 is sensed to be attached to the second weighing and bagging device 28, then the first set point is ignored and flow continues into the first container 12.

At set point two, the PLC slows the motor to a speed inducing medium material flow and the cylinder 52 is extended to pivot the chute 16 to an intermediate position above the edge 34 so as to direct 10% of the material flow into the first container 12 and the remaining 90% of the material flow into the second container 14. At set point three, cylinders 54 and 56 are retracted so that the chute 16 is pivoted to the second end position directing all of the material flow into the second container 14. After a predetermined elapsed time to allow for the fall of inflight material, the PLC releases the container 12 from the (left hand side) filling head 41 so another empty container 12 can be attached for filling. The above process is then repeated in relation to the second container 14 and so on.

The flow control valves 44 and 46 connected to the cylinders 52 and 54 respectively ensure the chute 16 pivots relative smoothly and slowly from an end to an intermediate position. The cylinders 50 and 56 do not use such a valve so they pivot the chute from an intermediate position to an end position as quickly as possible.

As an example in relation to filling a 20 kilogram bag, the first set point may be set at approximately 16 kilograms, the second set point approximately 19 kilograms and the third set point 19.95 kilograms (to allow for 0.05kg of inflight material).

The apparatus 100 in Fig. 11 includes a vibrating tray 102 gravity fed directly from a hopper 104 to supply flowable material to the first and second fixed guides 30 and 32. The position of the outlet edge 106 of the tray 102 over the edge 34 of the guides determines the division of the material flow.

Adjustment mechanisms 108 and 110 allow the tray position in each of the two intermediate positions to be varied to a fine degree, as discussed above.

In the example described above, there were three set points. As an example of a further variation, the first set point may be eliminated. As a safety precaution, at the set point indicating that a container is 85% full, the PLC can be programmed to check whether the other container is in place before pivoting chute 16 to an intermediate position as described above.

Fig. 12a shows the tray 102 in the first end position directing all the material flow to the first container. Fig. 12b shows the tray 102 in the first intermediate position directing the majority of the flow to the second container. Fig. 12c shows the tray 102 pivoting to the second end position. Fig. 12d shows the tray 102 directing all the flow to the second container. Fig. 12e shows the tray 102 in the second intermediate position directing the majority of the flow to the first container. Fig. 12f shows the tray 102 back in the first end position.

Fig. 13 shows a further embodiment of a filling apparatus 120 having a substantially vertical nozzle 122 connected to a hopper 124 by a flexible tube

126. A gate valve 128 controls flow from the hopper 124 to the tube 126. The cylinders 50,52,54 and 56 are connected to the nozzle 122 by yoke 130 and pivot the nozzle 122 in a substantially vertical plane to adjust its position relative to the edge 34 between the first and second guides 30 and 32 respectively.

Figs. 14 and 15 show yet a further embodiment of a filling apparatus 150 having a substantially horizontal nozzle 152 fed by an auger 154. The auger 154 is pivoted in a substantially horizontal plane to vary its position relative to the edge 34 of the guides 30 and 32.

INDUSTRIAL APPLICABILITY The main advantage of the embodiments of the filling apparatus is that the material flow need not be stopped, as in a single head filling machine, so whilst one container is filling the other can be removed and replaced to achieve a more efficient filling operation.

Another advantage is the effect on filling and weighing accuracy. Inaccuracies due to any change of flow rate, through surging or pulsing of the material flow, are greatly reduced because, during the final weighing off, only 10% of the actual maximum flow of the material is involved.

A related advantage is that the overall filling rate is no longer limited to a rate giving acceptable weighing off accuracy. In the example given, the filling flow rate for most of the container may be nine times the weighing off flow rate.

Further, the reduced rate of feed from the chute or the like in the intermediate position can be easily adjusted to give a desired degree of accuracy in relation to the type of product being weighed and filled.

Also, the load cells of the weighing and bagging devices can be linked to the visual displays so that the actual weight of the containers may be continually displayed to operators and through appropriate software can be linked to printers, data recorders or the like.

Another advantage, especially in relation to the food industry, is that the internal components of the apparatus are simple and easy to clean and maintain.

Although the invention has been described with reference to certain preferred embodiments, it will be appreciated by those skilled in the are that the invention is not limited thereto.