Filling containers with a flowable medium

Field of the Invention

This invention relates to a method and apparatus for the gravimetric filling of containers to a required volume with a flowable medium, such as a liquid, a granular medium or a powder.

Background of the Invention

In the gravimetric f illing of containers, such as cans, with a flowable medium in the form of a liquid such as paint, lubricating oil, edible oil, chemicals etc, a standard procedure is to locate a container at a filling station beneath a filling nozzle, with the volume of medium being deposited in a container being accurately controlled by weighing as filling progresses, with an associated control system serving to control timely opening and closing of a valve associated with the nozzle to ensure that the required volume of liquid medium is dispensed into the container. The filled container is then removed from beneath the filling nozzle so that the next empty container may be located at the filling station. Clearly, the filling cycle time depends on several factors, including the viscosity of the liquid medium, its flowrate, the volume of the container etc, before the container can be removed from the filling station, and furthermore, dependent for example on the characteristics of a liquid being dispensed, rapid acceleration of a static container away from the nozzle with a view to minimising the filling cycle time is sometimes not possible if spillage is to be avoided.

In another system, a rotary filling table is employed, but again containers are static beneath the filling nozzle during the filling cycle.

Object of the Invention

A basic object of the invention is the provision of an improved method and apparatus for filling of containers with a flowable medium. Summary of a First Aspect of the Invention

According to a first aspect of the invention there is provided a method of gravimetrically filling a succession of containers with a flowable medium comprising:

(i) seating a container to be filled on at least one endless conveyor so as to impart linear movement to the container at a predetermined speed;

(ii) associating a weighing system with the conveyor;

(iii) locating at least one openable and closeable filling nozzle above the container to be filled at a "start" position and traversing the filling nozzle linearly at the same speed and in same "filling" direction as that of the container;

(iv) providing a control means to control automatic closing of the filling nozzle upon completion of a filling step in accordance with data received from the weighing system; and

(v) traversing the nozzle in a return direction to the start position.

Summary of a Second Aspect of the Invention

According to a second aspect of the invention there is provided apparatus for carrying out the method of the first aspect comprising:

(i) at least one endless conveyor;

(ii) a weighing system associated with the, or each, conveyor;

(ii) at least one openable and closeable filling nozzle located above the, or each, conveyor and adapted, in use, to fill a linearly moveable container seated on the conveyor by the filling nozzle being mounted for traversing in the same "filling" direction as the conveyor and also at the save linear speed of the conveyor, and hence a container seated on the conveyor in a filling run, and mounted for traversing in a return direction to a start position for the filling of the next successive container; and (iv) control means to control automatic closing of the filling nozzle upon completion of a filling step in accordance with data received from the weighing means. Advantages of the Invention

The method and apparatus of the invention depart from the industry-standard procedure of filling a static container, by adopting the principle of filling a linearly and continuously moving container until a weight signal to the control means indicates that the required weight and hence volume of medium has been deposited in the container from a filling nozzle, which inventive concept not only reduces the time of the filling cycle, thereby offering cost savings and/or increased output, but also, by avoiding acceleration of a filled container, reduces, if not eliminates the possibility of spillage during removal of a filled container.

Preferred or Optional Features of the First Aspect of the Invention

A plurality of endless conveyors e.g. three, are provided, in series, a container to be filled is passed from the first conveyor where part filling is effected, to at least one second, downstream conveyor where further part filling, or final filling is effected. Preferred or Optional Features of the Second Aspect of the Invention

A single conveyor is employed.

A plurality of conveyors are employed, in series, each with an individual weighing means, with containers to be filled passed from an upstream conveyor to a downstream conveyor.

It will be appreciated that if a single conveyor is employed, then this needs to be of such length, and operated at such a linear speed, that filling to the required extent can be completed before a container reaches the discharge end of the conveyor.

The length of traverse of a filling nozzle needs to approximate to the length of the, or each, conveyor, both in its filling run and in its return run.

On the other hand, if multiple conveyors are employed, in series, it will be appreciated that a container that has been part-filled by a first nozzle associated with a first conveyor, may be passed to a second conveyor, and a second nozzle associated with the second conveyor may complete or continue filling.

Typically three to six conveyors are employed.

Control means is also provided to control opening of the, or each, nozzle.

Control means is also provided to synchronise traverse of the, or each, nozzle in the filling direction with linear movement of the container to be filled.

The number of filling nozzle employed corresponds to that of the conveyors, such that a bank of three to six nozzles would be advanced together in the filling direction and retracted together to the start position.

An on/off valve is associated with each nozzle.

The on/off valve(s) is/are pneumatically or solenoid activated.

Multiple filling nozzles are connected to a manifold for delivery and distributing the flowable medium involved.

The, or each, conveyor is a belt or chain conveyor.

The, or each, conveyor is of such a width that a plurality of containers may be seated laterally across the conveyor, each to be served by an individual filling nozzle.

The, or each, conveyor incorporates a drive system capable of varying the linear speed of the conveyor and hence the container.

The, or each, weighing system incorporates one or more load cells.

The control means also controls and/or adjusts the speed of the, or each, conveyor.

The speed of the, or each, conveyor is variable to accommodate the filling of containers having a range of volumes, as the rate of discharge from a filling nozzle is subject to constraint by factors such as the delivery piping from a tank or other reservoir, the capacity of a delivery pump, and the nature and temperature of the medium. The control means controls the speed of traverse of the, or each, filling nozzle, in the filling direction.

The speed of nozzle traverse in the filling run, is variable.

The control means initiates return traverse of the, or each, filling nozzle to the start position.

The control means includes a filling nozzle limit switch, a light positional sensor etc.

The return traverse is effected at relatively high speed to minimise the filling cycle time.

The control system also controls one or more pumps supplying the flowable medium to the nozzle(s), via any manifold.

Brief Description of the Drawing

One example of apparatus in accordance with the second aspect of the invention for carrying out the method of the first aspect is shown in the accompanying drawing.

Detailed Description of the Drawing

Apparatus 1 for the gravimetric filling of a container 2 comprises three endless conveyors 3A, 3B, in series, each conveyor 3 being associated with conventional load cells 4. Above each conveyor 3 is located a filling nozzle 5A, 5B, 5C with a solenoid operated, on-off control valve 6, and supplied from a product reservoir, by piping 7 or a manifold.

Each conveyor 3A, 3B, 3C has a conveying run 8 operable in the direction of arrow A, and a return run 9.

Each nozzle 5A, 5B, 5C is capable of traversing, during filling at the container 2, at the same linear speed as its conveyor 3A, 3B, as indicated by arrow B, from a "start" position at which filling is commenced, to a "stop" position at which filling is terminated, whereupon the nozzles 5A, 5B, 5C are traversed in the return direction, as indicated by arrow C.

It will be observed from the drawing, that with a three-conveyor apparatus, the container 2 is ½ filled with flowable medium M on each conveyor.

First and second light positioned sensors 1 and 11 are associated with each nozzle 5A, 5B, 5C unless all nozzles are ganged together, whereupon one pair of sensors 10 and 11 will suffice for supplying data to a control system to initiate opening of the nozzles 5A, 5B, 5C, commencement of the "filling" traverse, closing the nozzles 5A, 5B, 5C upon receipt of data from load cells 4, and initiation of the return traverse, back to the start position.

The conveyors 3A, 3B, 3C have variable speed drives, so that a single apparatus 1 can be used for filling differently sized containers, such that the dwell time of the nozzles 5A, 5B, 5C during the filling mode, discharges the required volume of flowable medium.

In addition, multiple containers 2 could be arranged laterally across conveyors 3A, 3B, 3C of suitable width, such that, with a similar multiple of nozzles, a plurality of nozzles could be simultaneously filled on each conveyor 3A, 3B, X, thus increasing the filling capacity of the apparatus 1.