GB2050319A - Applying closures to product- filled deformable containers - Google Patents

Abstract

Apparatus and a method are described for the application of closures to product-filled plastics bottles (10). The apparatus includes a chamber (8) which can be lowered into sealing engagement with the neck of the bottle. Within the apparatus a head (24) holds a closure (26) in spaced relationship from the bottle. Gas emitted from a 'T' piece (32) between the bottle and closure purges the closure and bottle of air and eventually purges the chamber of air. Closure of an outlet valve (44) allows the pressure to build up in the chamber. The 'T' piece is swung out of the way and the head brought down to fit the closure to the bottle. The bottle is then released from the apparatus. By filling the head space with a gas inert to the contents, the quality of the contents is maintained. By pressurising the head space, deformation of the bottle is resisted. <IMAGE>

Description

SPECIFICATION Applying closures to product-filled deformable containers The present invention relates to apparatus and methods for applying closures to product-filled deformable containers, in particular, but not exclusively, plastics bottles.

Because of their relatively flexible nature, plastic botties can suffer from "panelling", that is to say, inward deformation or buckling caused by subatmospheric pressures, which, as described below, may occur in the bottle head space after product filling and closure. Such panelling, which usually occurs in the tubular side wall of the bottle, is undesirable as it impairs the appearance of the bottle and consequently reduces its sales appeal.

The sub-atmospheric pressures tending to cause panelling may be generated when a hot-filled product and gas in the bottle head space cool subse quentto filling and closure of the container. In addition or alternatively, they may be caused by interaction ofthe product with the container material and/or with oxygen within the container.

The present invention seeks primarily to provide an apparatus and method for applying a closure to a product-filled deformable container, by-which subsequent panelling of the container due to subatmospheric pressure generated therein is prevented or substantially reduced. Accordingly, from one aspect, the invention provides apparatus for applying a closure to a product-filled deformable container comprising means defining a chamber having an aperture arranged to sealingly receive a region of the container adjacent an opening thereof whereby to communicate the container head space with the chamber, a head located within the chamber arranged to receive a closure for the opening of the .container and operable to move the closure from -a-position lying spaced from the container to a position in which it can seal the closure onto the container, pressurising meansforthe chamber and arranged for pressurising the chamber and the container head space with gas to a predetermined pressure level, and means operable when the said predetermined pressure level of gas is reached to cause the head to apply the closure to the container and thus seal gas under pressure within the container head space.

From a second aspect the invention provides a method of applying a closure to a product-filled deformable container the method comprising the steps of placing the open upper end of the container in a chamber so as to communicate the container head space with the chamber, holding a closure within the chamber spaced from the container, pressurising the chamber and the container head space with gas to a predetermined pressure level, applying the closure to the container so as to seal gas under pressure within the container head space and withdrawing-the closured container from the chamber.

According to the invention from a third aspect, there isstiSl further provided a -prnduct4i I led plastics bottle having an opening sealed by a closure and having its head space occupied by a gas which is substantially inert to the product, the gas having just sufficient pressure to inhibit deformation of the bottle by the environmental pressure.

Apparatus and a method for the closuring of bottles, and embodying the invention, will now be described by way of example, with reference to the accompanying diagrammatic drawing which shows a section through the apparatus, The apparatus to be described is arranged to fill with nitrogen underpressure, the head space of bottles of plastics material containing hot tomato ketchup (or similar hot-filled and oxygen-sensitive products). As explained above, the use of pressure assists in preventing partial collapse or deformation of the bottle due to sub-atmospheric pressures developing within the bottle after its closure. Nitrogen is selected because it is substantially inert relative to the tomato ketchup; (oxygen or air tends to oxidize the tomato ketchup and cause discolora- tion).

As shown in the sole Figure, the apparatus includes a base plate 2 defining a central circular platform 2a on its upper surface. A sleeve 4 mounted on the upper surface of the base plate is located by the platform 2a. A top plate 6 is supported on the sleeve 4 and has a circular platform 6a located on its under surface. The platform 6a extends into the sleeve 4 and locates the top plate on the sleeve.

Three tie rods 8 (only one shown) equiangularly spaced about the axis of the sleeve 4 couple the top and base plates together so that the top and base plates and the sleeve4form a unitary structure defining a chamber 8.

The base plate 2 defines an opening 2b through which the head of a bottle 10 can pass to lie within the chamber. The lower end of the opening 2b is chamfered so as to conform to the tapering profile of the head of the bottle 10. The chamfered portion is provided with an annular groove which accommo datesa ring seal 12. The ring seal 12 acts to seal the space between the opening 2b and-the head of the bottle when inserted into the chamber.

The top plate 6 is rigidly secured to the underside of a supporting beam by a nut 16 and hollow bolt 18.

The bolt 18 is in screw-threaded engagement with a screw-threaded bore in the top plate and extends through an aligned bore in the supporting beam 14 before screw-threadedly engaging the nut 16.

The bolt 18 has a bore which is coaxial with the opening 2a in the base plate.

Extending through the bore in the bolt 18 is a rod 20. The gap between the rod and the bore is seated by two axially spaced ring seals 22.

A capping head 24 located within the chamber 8 is rigidly secured to the lower end of the rod 20. The capping head is arranged to receive and hold a cap 26.

A gas supply tube 28 is supported by an annular boss 30. The boss 30 is rotatably supported in a recess in the upper surface of the top plate 6. The tube 28 extends through the top plate into the chamber 8 and terminates in a bent portion 28a extending at right-angles to the rema-inder of the tube 28. The bent portion carries a 'T' piece 32 providing two gas outlets, one directed vertically upwardly and the other directed vertically downwardly.

A control lever 34 rigid with the boss 30 is partially housed in a recess in the underside of the beam 14.

Displacement of the projecting end of the lever causes rotation of the boss 30 which in turn effects displacement of the 'T' piece 32 between a position in which the outlets are axially aligned with the rod 20 and the opening 2b, and a position in which the 'T' piece lies adjacent the inner wall of the cylinder 4 out of the path between the head 24 and the opening 2b.

Nitrogen gas under pressure in a cylinder (not shown) is fed via a pressure reducer 36 to a valve 38 and thence via a coupling 40 to the tube 28.

A gas outlet passage 42 defined in the top plate 6 extends from an opening in the underside of the plate to a coupling recess in the outer circumferential surface of the plate 6.

A gas conduit is coupled into the coupling recess and supplies gas to an exit valve 44 from where the gas is vented to the atmosphere.

In operation, the cycle starts with the valve 38 closed and the valve 44 open, with the head 24 in the lowered position and with the 'T' piece swung into a position in which it lies against the wall of the cylinder 4.

A mechanism not shown passes a bottle cap through the opening 2b and causes itto be engaged by the head 24. The head 24 is then displaced into a raised position. Thereafter a further mechanism not shown brings a bottle 10 into alignment with the opening 2b and the cross beam 14 is lowered so that the head of the bottle enters the chamber 8 and the outer wall is held in sealed engagement with the ring seal 12. The lever 34 is operated to bring the 'T' piece to a position between the cap 26 and the open top of the bottle 10. At this time the valve 38 is opened and nitrogen emerging in two jets from the 'T' piece 32 initially purges air from the head space in the bottle and from the cap 26 and then eventually from the chamber 8 altogether.At this point, the valve 44 is closed so that the pressure within the chamber builds up substantially to the level set by the regulator 36.

The lever 34 is again operated to displace the 'T' piece 32 from between the head 24 and the bottle head. Thereafter the rod 20 is displaced downwardly by a mechanism (not shown) to clause the cap 26 to engage the top of the bottle 10 and thereafter the cap 26 is deformed around the top to seal the cap to the bottle. The valve 38 is closed off. The cross beam 14 is raised and the pressure of gas within the chamber forces the bottle from the chamber 8 and disengages the cap from the head 24.

The sealed pressurised bottle is discharged for packing, the valve 44 is opened and the apparatus is ready for another cycle.

Advantageously, the gas regulator 36 is adjustable over a pressure range of from 0.07 to 0.70 Kg.cm2. A preferred setting is 0.14 Kg;cm2.

Instead of the press fit cap 26 described, the head can be arranged to fit a screw cap on the bottle if the bottle is provided with the appropriate screw thread.

In experiments which have been carried out using the described apparatus, it was found that plastics bottles filled with hot tomato ketchup and sealed with the head space filled with nitrogen under a pressure of 0.14 Kg/cm2 suffered no deformation over an initial period of three months and no discoloration of the tomato ketchup was observed over the same period. In the absence of the nitrogen, that is to say, with the head space filled with air at atmospheric pressure when the closure was applied deformation or "panelling" of the bottle tended subsequently to occur, particularly at their side walls; in addition the tomato ketchup became discoloured by oxygen.

The apparatus and method described can be used with plastics bottles containing contents other than tomato ketchup, for example motor oil or orange juice using nitrogen, for example, under a pressure similar to that disclosed above.

It will be appreciated that gases other than nitrogen can be used to fill the head space of bottles, but care should be taken to select the gas so that it does not substantially react with the contents of the bottle. Air may be used in appropriate circumstances.

It will also be appreciated that the apparatus can be used or adapted for use with deformable containers other than plastics bottles.

The filling of the head space of deformable containers with a gas under pressure resists deformation (sometimes known as panelling) of the containers. In cases were the product is oxygensensitive, it may, by the use of an inert gas, also assist in maintaining the quality of the product.

Claims (17)

1. Apparatus for applying a closure to a productfilled deformable container comprising means defining a chamber having an aperture arranged to sealingly receive a region of the container adjacent an opening thereof whereby to communicate the container head space with the chamber, a head located within the chamber arranged to receive a closure for the opening of the container and operable to move the closure from a position lying spaced from the container to a position in which it can seal the closure onto the container, pressurising means for the chamber and arranged for pressurising the chamber and the container head space with gas to a predetermined pressure level, and means operable when the said predetermined pressure level of gas is reached to cause the head to apply the closure to the container and thus seal gas under pressure within the container head space.

2. Apparatus according to claim 1, wherein the pressurising means comprises gas feeding means projecting into the chamber and arranged to direct a gas substantially inert to the said product into the chamber head space for purging the same of air.

3. Apparatus according to claim 2 wherein the gas feeding means comprises a swivelling gas conduit terminating in aT' piece which provides oppositely directed gas jets, the gas conduit being swivellable between a first position in which it lies between the closure and the container and has its jets respectively directed at the closure and the container head space, and a second position in which it does not obstruct the motion of the head towards the container.

4. Apparatus according to claim 2 or claim 3, wherein the gas feeding means includes a pressure regulating valve settable to a pressure corresponding to the predetermined pressure level.

5. Apparatus according to any one of claims 1 to 4, including a gas exit valve for said chamber operable to seal or release the gas within the chamber when a container is sealed therein.

6. Apparatus according to any preceding claim, wherein said head is mounted on a rod which is slidable along a bore in the chamber defining means.

7. Apparatus according to any preceding claim, wherein the said aperture in the chamber is circular and supports a ring seal for sealingly engaging the tapered neck of a container of circular cross-section.

8. Apparatus according to any preceding claim, wherein said chamber defining means is supported for vertical displacement relative to a said container.

9. A method of applying a closure to a productfilled deformable container the method comprising the steps of placing the open upper end of the container in a chamber so as to communicate the container head space with the chamber, holding a closure within the chamber spaced from the container, pressurising the chamber and the container head space with gas to a predetermined pressure level, applying the closure to the container so as to seal gas under pressure within the container head space, and withdrawing the closured container from the chamber.

10. A method according to claim 9 wherein said container comprises a bottle of plastics.

11. A method according to claim 9 or claim 10, wherein said gas is air.

12. A method according to claim 10, wherein said product is tomato ketchup and said gas is nitrogen.

13. A method according to any one of claims 9 to 12, wherein said predetermined pressure is in the range from 0.07 to 0.70 Kg/cm2.

14. A product-filled plastics bottle having an opening sealed by a closure and having its head space occupied by a gas which is substantially inert to the product, the gas having just sufficient pressurn to inhibit deformation of the bottle by the environmental pressure.

15. A bottle according to claim 14 wherein the product is tomato ketchup, the gas is nitrogen and the pressure of the gas lies within the range 0.07 to 0.70 Kg/cm2.

16. Apparatus for applying a closure to a product-filled deformable container, substantially as hereinbefore described with reference to the accompanying drawing.

17. A method of applying a closure to a productfilled deformable container, substantially, as hereinbefore described with reference to the accompanying drawing.