GB2250258A - Removing particles from packaging web - Google Patents

Abstract

Apparatus for removing particles from the sealing surface of a packaging web advancing in one direction comprises gas supply means (6) for directing at least one jet of gas at the advancing sealing surface to dislodge the particles, and suction means (5, 7) for applying suction in the vicinity of the jet or jets to remove the dislodged particles; wherein, in use, the apparatus (5, 6, 7) remains stationary above the advancing web. The apparatus can be used for removing crumbs in a cheese packaging line, to reduce the number of incidents of inadequately sealed products. <IMAGE>

Description

PARTICLE REMOVAL APPARATUS This invention relates to an apparatus for removing particles from the sealing surface of a packaging web, and is particularly, but not exclusively, for use in packaging crumb-producing substances such as cheese in plastics packs with sealed edges.

In a typical process for packaging cheese in a plastics pack of the type that is vacuum sealed, a continuous web having preformed recesses is conveyed to a loading station at which blocks of cheese are placed into each recess. A sheet of plastics in the form of another continuous web is then placed over the filled recesses, the excess air removed by suction and the two webs thermally bonded together to form an hermetic seal.

However, the cut blocks of cheese that are placed in the recesses tend to produce crumbs, and when these crumbs contaminate the surface of the web surrounding the recess there is a danger that they will interfere with the sealing procedure, resulting in leaky packages.

It has been attempted to remove the crumbs from the sealing surfaces of the recessed web, prior to overlaying the second web, by suction. However, cheese crumbs tend to adhere to the surface of the plastics web and removal by suction has not been found successful.

More success has been achieved by directing jets of air at the web in order to dislodge the crumbs, but in many instances the crumbs then resettle in another position such that they still contaminate the seals.

Guards have been devised to protect some of the web surface, but these are only able to cover the longitudinally extending sealing surface, and in some instances the jets of air cause crumbs to lodge under the guards.

According to the present invention there is provided apparatus for removing particles from the sealing surface of a packaging web advancing in one direction, the apparatus comprising gas supply means for directing at least one jet of gas at the advancing sealing surface to dislodge the particles, and suction means for applying suction in the vicinity of the jet or jets to remove the dislodged particles; wherein, in use, the apparatus remains stationary above the advancing web.

Preferably the or each jet of gas is directed onto the web at an angle having a component in a direction opposite to that of the web advancement. If necessary, the angle could be adjustable according to several factors but generally speaking an angle of 30 to 700 to the horizontal gives good results.

Preferably the gas supply means is arranged such that the or each jet of gas hits the web immediately prior to the web passing beneath the suction means.

This enables the suction effect to operate before there is any serious risk of the particles re-adhering to the web.

Conveniently the suction means comprises an elongate hood disposed transversely with respect to the direction of advancement of the web. Alternatively the suction means comprises a plurality of hoods extending in a line disposed transversely with respect to the direction of advancement of the web.

Preferably the gas supply means comprises a duct communicating with the interior of which is a plurality of nozzles for directing gas under pressure.

The apparatus preferably includes pump means for creating a sub-atmospheric pressure within the suction means.

The apparatus preferably includes compressor means for supplying gas under superatmospheric pressure to the gas supply means.

There can be provision for the pump means and compressor means to operate continuously, in use.

However, either or both of the pump means and compressor means could operate intermittently with short inoperative phases between longer operative phases, and with the operative phases of the pump and compressor means at least partially overlapping or fully coinciding.

Apparatus according to the present invention can be interposed on a conventional packaging line between the filling station and the sealing station without any, or without any significant, disruption of the existing components.

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 drawing, in which: Figure 1 is a schematic view from above of part of a packing line; Figure 2 is a schematic cross-sectional view of an embodiment of apparatus according to the invention; and Figure 3 is a schematic view from beneath of the apparatus of Figure 2.

Referring to the drawings, in Figure 1 in a first stage, a continuous web 1 of plastics material having preformed recesses 2 is conveyed on a conveyor 20 to the left as viewed in the drawing. As the web advances, the recesses 2 are individually filled with blocks of cheese 3 that have been cut to size in a previous stage of the production procedure. The web 1 moves on to the next stage (generally indicated by reference numeral 21) of the procedure where a second web is laid over the filled, pocketed web 1, air is extracted, the two webs are heat sealed together in the area around the outer periphery of the recess or pocket, and the sealed-together webs are then cut to form individual, hermetically sealed packs 4. Further description of this second stage of the procedure is not given because it is a typical vacuum packing operation.

Irrespective of whether the blocks of cheese are positioned manually or automatically there is a tendency for crumbs to be produced and if these crumbs lodge on the upper surface of web 1 between the recesses or pockets, they interfere with the subsequent seal formation resulting in a leaky package.

The apparatus according to the present invention is interposed between the first and second stages. The apparatus is shown more clearly in Figure 2 which shows schematically a preferred embodiment of crumb removing apparatus according to the present invention. A row of suction hoods 5 is mounted at the end of the pocket filling stage of the process. Mounted close to, or preferably within, the hoods, as shown more clearly in Figure 3, is a series of air jets. In the embodiment illustrated the jets are formed by a single pipe 6 having a series of holes through which compressed air escapes from the pipe. However it would be possible to use a series of separately run jets for each gas supply means. Likewise the suction pipes 7 of the hoods 5 may be interconnected, or separate.

The holes in the pipe 6 are positioned so that the air jets are directed at an angle contrary to the direction of motion of the web. Thus the air jets hit the web a short distance prior to it passing under the suction hoods. When the air hits the web it causes turbulence which lifts and agitates the cheese crumbs, and these crumbs are then readily sucked up as they pass under the hoods.

It will be appreciated that instead of air it would be possible to use jets of another gas such as nitrogen. Also, instead of a series of hoods the suction could be achieved by a single elongate hood extending over the width of the web. A typical spacing from the lower end of the hoods 5 and pipe 6 to the web surface is about 25 mm.

The combined action of agitation by air bursts to move stuck crumbs followed by suction enables substantial reduction in the number of leaky packages produced.

At the end of the pocket filling stage there is generally a crossbar 8, such as that illustrated in Figure 1, which prevents misplaced blocks from passing into the sealing stage. In general, it is desirable to mount the jet/suction assembly after the crossbar so that it is also protected from damage.

Claims (13)

1. Apparatus for removing particles from the sealing surface of a packaging web advancing in one direction, the apparatus comprising gas supply means for directing at least one jet of gas at the advancing sealing surface to dislodge the particles, and suction means for applying suction in the vicinity of the jet or jets to remove the dislodged particles; wherein, in use, the apparatus remains stationary above the advancing web.

2. Apparatus according to claim 1, wherein the arrangement of the gas supply means is such that the or each jet of gas is directed onto the web at an angle having a component in a direction opposite to that of the web advancement.

3. Apparatus according to claim 1 or claim 2, in which the or each jet of gas is arranged to hit the web immediately prior to the web passing beneath the suction means.

4. Apparatus according to any preceding claim, in which the gas supply means for directing the jet or jets of gas is located within the suction means.

5. Apparatus according to any preceding claim, wherein the suction means comprises an elongate hood disposed transversely with respect to the direction of advancement of the web.

6. Apparatus according to any one of claims 1 to 4, wherein the suction means comprises a plurality of hoods extending in a line disposed transversely with respect to the direction of advancement of the web.

7. Apparatus according to any preceding claim, wherein the gas supply means comprises a duct communicating with the interior of which is a plurality of jets for directing gas under pressure.

8. Apparatus according to any preceding claim, which includes pump means for creating a sub atmospheric pressure within the suction means.

9. Apparatus according to any preceding claim, which includes compressor means for supplying gas under superatmospheric pressure to the nozzle means.

10. Apparatus according to claims 8 and 9, which includes provision for the pump means and compressor means to operate continuously, in use.

11. Apparatus substantially as hereinbefore described with reference to, and as illustrated in, Figures 2 and 3 of the accompanying drawing.

12. A packaging line which includes an apparatus according to any preceding claim.

13. A packaging line according to claim 12, substantially as described, with reference to, or as illustrated in, Figure 1 of the accompanying drawing.