Filling valve

Abstract

 A filling valve for use in a container-filling plant or the like is disclosed, which valve is provided with movable closure means (4) which are biassed to close the filling valve, characterised in that the filling valve further comprises:

i) a flexible sealing member (10) adapted to provide a seal between the mouth of a container (6) to be filled and the filling valve when the filling valve is in use, and

ii) opening means (7) adapted to move said movable closure means (4) by a predetermined amount so as to open the filling valve when a container (6) is to be filled.

Description

[0001] This invention relates to a valve for use in bottle and container filling equipment.

[0002] In the bottling and filling industry, there is a need to be able to fill bottles and containers to a high degree of accuracy, particularly in the case of large filling plant, where even a very slight overfill per bottle can lead to a substantial erosion of profit margins over an extended period of time. It is particularly difficult when using existing filling machinery accurately to fill non-rigid containers such as plastic milk containers.

[0003] Two main forces are necessary for the operation of a filling valve. The first force is that which is required to seal the top of the container against the filling unit. The second force is that which is required to open the valve. This second force is generally high in order to prevent leakage through the filling valve when closed. With existing filling valves, the container to be filled is used to apply both these forces. Since the force required to open the valve is large, this can lead to distortion of the container and consequently to inconsistent fill levels.

[0004] According to one aspect of the present invention, there is provided a filling valve which comprises a filling member provided with movable closure means, which closure means are urged by resilient means to close the filling valve, characterised in that there is provided:

i) a flexible sealing member on said filling valve, which sealing member is adapted to provide a seal between the mouth of a container to be filled and the filling valve when the filling valve is in use, and

ii) a controllable filling valve opening mechanism which is adapted to move said movable closure means against said resilient means by a predetermined amount so as to open the filling valve when a container is to be filled.

[0005] According to another aspect of the present invention, there is provided a filling valve provided with movable closure means, which closure means are biassed to close the filling valve, characterised in that the filling valve further comprises:

i) a flexible sealing member adapted to provide a seal between the mouth of a container to be filled and the filling valve when the filling valve is in use, and

ii) opening means adapted to move said movable closure means by a predetermined amount so as to open the filling valve when a container is to be filled.

[0006] The flexible sealing member is arranged so that a container to be filled may be held against the filling valve in an air-tight manner without the need for a force whose magnitude would be likely to cause distortion of the container. Advantageously, the flexible sealing member is arranged to enable an airtight seal to be maintained over a predetermined range of positions of the container relative to the filling valve.

[0007] The controllable filling valve opening mechanism is preferably controlled by way of a cam rail. In use, the valve opening mechanism moves relative to the cam rail in such a way that the elevation of the cam rail relates to the degree by which the valve opening mechanism moves the closure means of the filling valve. The closure means are thereby moved against the resilient means to open the filling valve without the need for a large force to be applied through the container which is to be filled. Advantageously, the opening mechanism is adjustable to move the closure means by a distance delimited by the range of flexibility defined by the flexible sealing member. This allows the fill level to be altered during the operation of the bottling plant without the need to halt production. This adjustment may be carried out simply by raising or lowering the cam rail.

[0008] In certain embodiments of the present invention, override means are provided which prevent the valve opening mechanism from opening the filling valve unless a container is sealed against the flexible sealing member. These override means preferably comprise a cam which may be actuated so as to compensate for the elevation of the cam rail, thereby preventing the valve opening means from moving the closure means and thereby opening the filling valve. The override means may also be used to provide a further degree of fill level control if desired.

[0009] In a preferred embodiment of the present invention, weighing means are provided which allow the weight of the container and hence the volume of product to be monitored while the container is being filled. Advantageously, the weighing means are linked to the opening mechanism by way of control means. The control means advantageously incorporate a feedback system through which the opening mechanism may be continuously adjusted in response to the fill volume monitored by the weighing means.

[0010] For a better understanding of the present invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:

FIGURE 1 shows a cross-section through a known filling valve when closed;

FIGURE 2 shows the known filling valve of Figure 1 when open;

FIGURE 3 shows a cross-section through a filling valve according to the present invention;

FIGURE 4 shows the filling valve of Figure 3 when open;

FIGURE 5 shows six stages in the process of filling a container using a filling valve according to the present invention; and

FIGURES 6 and 7 show a controllable valve opening mechanism suitable for use with the present invention.

[0011] A conventional filling valve, as shown in Figure 1, is sealed by closure means comprising a sleeve 4 which is urged by resilient member 1 to cover the air tube 3 of the filling member 8. This prevents product flow from tank 5. A number of fill level spacers 2 are situated underneath a collar 9 which protrudes from the sleeve 4. In order to fill a container 6 with product, the container 6 is lifted up to form a seal with the fill level spacers 2 as shown in Figure 2. By lifting the container 6 further, sleeve 4 is lifted against the force of resilient member 1 and allows the air in the container 6 to exhaust up the air tube 3. This allows product to flow around the outside of the fill member 8 from the tank 5 into the container 6. When the liquid level in the container 6 reaches the bottom of sleeve 4, preventing further air being exhausted up air tube 3, the flow of product into the container 6 ceases. It is thus apparent that the product fill level in the container 6 is determined by the distance between the fill level spacers 2 and the bottom of the sleeve 4. In order to adjust this fill level it is necessary to vary the number of spacers 2 fitted. It is therefore not only difficult to achieve fine fill level accuracy, but also time consuming on a continuous multiple head filler which has to be stopped and have a large number of valves adjusted. Furthermore, with such existing valves, it is possible for the seal between the top of the container 6 and the fill level spacers 2 to break before the sleeve 4 seals the air tube 3. If this happens, air is allowed to leak out of the top of the container 6, which enables excess product to leak from the tank 5 before the valve is completely shut. One of the reasons for this is that the force required to push up the sleeve 4 is imparted through the container 6. If the container is made of a flexible plastics material, it is likely to buckle under such compression.

[0012] Figure 3 shows the filling valve of the present invention when closed. As in a conventional filling valve, the closure means consisting of sleeve 4 is urged by resilient member 1 to cover the air tube 3 of the filling member 8. In place of the fill level spacers 2 of Figures 1 and 2, there is provided a light flexible seal 10. An controllable valve opening mechanism, of which only the lifting arms 7 are shown, is also provided.

[0013] When the filling valve of the present invention is in use, as shown in Figure 4, the container 6 to be filled is brought up to the light flexible seal 10 and thereby forms an air-tight seal with the filling valve without the need for any great force to be exerted. Container 6 is then lifted further, and at the same time the arms 7 of the controllable valve opening mechanism lift sleeve 4 against the force of resilient member 1, allowing the air in the container 6 to exhaust up the air tube 3 which then allows product to flow down the outside of the air tube 3 and into the container 6. When the liquid level in the container 6 reaches the bottom of sleeve 4, preventing further air from being exhausted up the air tube 3, the flow of product into the container 6 ceases. It is therefore apparent that the liquid fill level in the container 6 is partially determined by the range of flexibility of the light flexible seal 10, i.e. the degree of seal deformation as shown in Figure 4. In order to adjust the fill level with the filling valve of the present invention, all that is necessary is to adjust the degree by which the controllable valve opening mechanism moves the sleeve 4 within the range of flexibility of the light flexible seal 10. This has the effect of varying the level of the lower end of sleeve 4 relative to the top of the container 6, which not only allows continuously variable adjustment to be made to the fill level, but also allows such adjustment to be made while the filling plant is running. In a typical filling plant provided with filling valves according to the present invention, the range of adjustment required would be around ±2mm, but this range may be extended for larger containers (for example up to ±50mm) and reduced for smaller ones (for example down to ±0.1mm).

[0014] Six steps in the process of filling a container using a filling valve according to the present invention are shown in Figure 5. At the start of the filling sequence, a container 6 is lined up beneath a filling valve. The container 6 is then lifted so that a seal is formed between the mouth of the container 6 and the light flexible seal 10. When the seal has been made, the container 6 is lifted further, and the controllable valve opening mechanism simultaneously lifts the sleeve 4 upwards against the force of the resilient member 1 so as to allow product to flow into the container. The final fill level may be finely regulated by adjusting the controllable valve opening mechanism. In order to determine the required fill level, the container and its contents may be weighed at this point, and the controllable valve opening mechanism adjusted accordingly by way of a feedback control arrangement (not shown). Once the fill level is satisfactory, the container 6 is lowered while the controllable valve opening mechanism simultaneously allows the sleeve 4 to be pushed back down over the air tube 3 by the resilient member 1. Finally, the container 6 is lowered further so as to break the seal between the mouth of the container and the light flexible seal 10.

[0015] A suitable arrangement for the controllable valve opening mechanism is shown in Figures 6 and 7. The arms 7 of the controllable valve opening mechanism are mounted on a platform 11 which is urged upwards by springs 12. The platform 11 also includes a roller 13 which runs against a cam rail 14. In use, the valve opening mechanism moves along the cam rail. If a container 6 is correctly sealed against the filling valve when the valve opening mechanism moves onto the elevated portion of the cam rail 14, then the platform 11 will be lifted by the springs 12, and the arms 7 of the valve opening mechanism will thereby lift the sleeve 4 and open the filling valve. If no container 6 is present, or if the container 6 is not properly sealed against the filling valve when the valve opening mechanism moves to the elevated portion of the cam rail 14, then a control cylinder 15 is actuated. The control cylinder 15 moves cam 16 so that it pushes platform 11 down against the springs 12, thereby preventing the arms 7 from lifting the sleeve 4, as shown in Figure 7. The cylinder 15 may also be used in a finely controlled manner to actuate cam 16 in order to give a further degree of fill level control. Any convenient control and/or sensing means may be used to operate the control cylinder 15.

Claims

1. A filling valve provided with movable closure means (4), which closure means (4) are biassed (1) to close the filling valve, characterised in that the filling valve further comprises:

i) a flexible sealing member (10) adapted to provide a seal between the mouth of a container (6) to be filled and the filling valve when the filling valve is in use, and

ii) opening means (7) adapted to move said movable closure means (4) by a predetermined amount so as to open the filling valve when a container (6) is to be filled.

2. A filling valve as claimed in claim 1, wherein the flexible sealing member (10) has a predetermined range of flexibility allowing the seal between the mouth of the container (6) and the filling valve to be maintained over a predetermined range of relative dispositions.

3. A filling valve as claimed in claim 1 or 2, wherein the opening means (7) is adapted to move the closure means (4) through a range delimited by the range of flexibility of the flexible sealing member (10).

4. A filling valve as claimed in claim 1, 2 or 3, wherein the opening means (7) is controlled by way of a cam rail (14).

5. A filling valve as claimed in any preceding claim, further comprising override means (15) arranged to provide a secondary level of valve control in addition to the opening means (7).

6. A filling valve as claimed in claim 5, wherein the override means (15) comprises a cam which, in use, may be actuated to control the movement of the movable closure means (4).

7. A filling valve as claimed in any preceding claim, further comprising weighing means which, in use, is arranged to monitor the weight of a container (6) being filled.

8. A filling valve as claimed in claim 7, further comprising control means which, in use, is arranged to control the opening means (7) in response to signals generated by the weighing means.

Drawing