IE53007B1 - Apparatus for aseptic filling of and method of packing liner bags - Google Patents

Abstract

This invention relates to a method of aseptically packaging fluid material, especially milk, in liner bags, and to the filling apparatus used in carrying out the method. In particular, the apparatus of the 5 invention is designed to maintain previously sterilised liner bags, which are double wrapped after manufacture, in a totally sterile state while the bags are unwrapped prior to filling and while the bags are being filled with a foodstuff such as milk.

Description

This invention relates to a method of aseptically packaging fluid material, especially milk, in liner bags, and to the filling apparatus used in carrying out the method. In particular, the apparatus of the invention is designed to maintain previously sterilised liner bags, which are double wrapped after manufacture, in a totally sterile state while the bags are unwrapped prior to filling and while the bags are being filled with a foodstuff such as milk.

There is now a trend in the food and drinks industry to pack food and drink in flexible containers which are then located in a semi-rigid or rigid outer case, as distinct from in the more traditional metal or glass containers, and the present invention, although not so limited, has been specifically designed for filling the liner bags of the bag-in-box type container.

Attempts have been made in the past to provide aseptic conditions for filling liner bags with foodstuff and while these have been relatively successful for foodstuff having a high acid content, there has only been limited success in packaging low acid foodstuff in this way, which has required that the foodstuff is subsequently kept refrigerated.

In- British Patent Specification No. 1522654 an aseptic packaging process is disclosed wherein semi-rigid containers are extruded and blown in a sterile enclosure, and then the necks of the containers are cropped, the containers filled and capped all within the same enclosure, which is subjected to a laminar air flow. This apparatus is however totally unsuited to the aseptic filling of flexible containers, which must be pre-formed and sterilised, e.g. in a factory, and then taken as required to the filling machine, e.g. at a dairy, where they are unwrapped and filled all under sterile conditions.

Another machine for semi-rigid containers, Is shown in British Patent Specification Ko. 1339995. This machine does not, however, incorporate a laminar air flow, although the containers are formed butside the machine. This machine, however, cannot be used for filling flexible .containers of the bag-in-box type.

In one known method of filling flexible containers apparatus is used in which the filling and discharge spout of the liner bag is surrounded by a stream of clean heated and chlorinated air during the de-capplng, filling and re-capping operation, but it is not possible to prevent germs from accumulating on the remainder of the liner bag. Attempts have been made to solve this problem by placing the whole liner bag in an atmosphere of chlorinated hot air, but even this does not result in totally aseptic filling conditions because it was found that the moving parts of the filling machinery and braided hoses, etc, in spite of being frequently cleaned, would sometimes attract and harbour unwanted germs and bacteria. We have now designed a method and an apparatus which we believe provides a wholly aseptic filling environment.

According to the present invention, we provide a method of aseptically packaging fluid material, comprising capping a plurality of liner bags, forming them into a batch, wrapping the batch of bags, and then sterilising the wrapped batch of bags, and subsequently, at a filling station, removing a wrapping from the batch of liner bags, feeding the batch of bags into a laminar flow cabinet through which a sterile gas is caused to pass, and presenting individual bags to a de-capping, filling and re-capping station located within the laminar flow of glass,so that the bags are individually de-capped, filled with a predetermined amount of fluid material and re-capped by the de-capping, filling and re-capping device, all under totally sterile conditions, removing said filled re-capped bags from the cabinet, and placing said filled bags In an outer case or other container.

Although the bags may be manufactured from preperforated sheet material and fan-folded, in which case they would only be single wrapped and sterilised, and fed to the laminar flow cabinet after removal of the wrapping in a sterile area adjacent the cabinet, it is preferred to perform the packaging method manually.

For the manual method, double wrapping of the bags is preferred. Preferably, therefore, the bags are manufactured, capped, double wrapped and sterilised in a factory which may be located many miles from the filling apparatus. This could be located in a dairy if milk was the product being packaged. The inner wrapping is preferably removed from the bags inside the cabinet, preferably within an area which is covered by ultra-violet radiation.

Also according to the present invention, we provide aseptic liner bag filling apparatus for filling prewrapped, sterile liner bags comprising a laminar flow cabinet, means to cause a sterile gas to be passed through the cabinet in a laminar flow, a de-capping, filling and re-capping device located within th.e. cabinet, an access opening in a wall of the cabinet through which liner bags which have not been manufactured within the cabinet may be introduced into the cabinet, so that their capped filling spout may be offered up to said device, which automatically de-caps the bags, fills them with a predetermined amount of fluid and re-caps them, and an exit opening in the cabinet through which said filled and re-capped bags may be removed from the cabinet for subsequent insertion within an outer case or other container.

Preferably, the laminar flow cabinet is of generally rectangular cross-section in the direction of gas flow through the cabinet, there being a perforated inlet wall at one end of the cabinet through which filtered sterile gas is introduced at a regular rate over the full cross-sectional area of the cabinet so as to pressurise the cabinet and prevent ingress of airborne bacteria.

Preferably,. at least a lower portion of the end of the cabinet opposite the inlet wall is open to provide the access opening, the remainder of that end of the cabinet being closed by a transparent sheet of material.

Preferably, the laminar flow cabinet has a tray in a lower region thereof on which bags to be filled manually are removed from an inner wrapper and stored at a downstream end of the work table.

Preferably, the exit opening for the filled bags extends the full length of the cabinet and is provided in a front wall of the cabinet, just above the cabinet base, the opening being deep enough to permit an operator to reach in to remove an overwrapper from the bags on the tray and to allow the operator to present individual bags one at a time to the de-capping, filling and re-capping device and to allow the operator subsequently to remove the filled bags from the cabinet and place them in an outer case or other container.

Preferably, apart from the exit opening, the front wall of the cabinet is closed by a transparent sheet of material.

Preferably, the cabinet also includes further closed compartments in which filters and various control apparatus are housed, which compartments are separated off from the laminar air flow.

Preferably, an ultra-violet radiation emitter is located with the laminar air flow inside the cabinet.

A preferred embodiment of manually operated aseptic filling apparatus in accordance with the invention is now described by way of example with reference to the accompanying schematic drawing which is a front perspective view.

Referring to the drawing, the apparatus comprises a laminar flow cabinet 1 supported on a stand 3. The laminar flow cabinet is of generally known construction and a sterile gas, for example air, is introduced into a working area 4 of the cabinet through a uniformly perforated generally rectangular wall 5 which forms one end of the area 4. The opposite end is partially closed by a transparent sheet of material, but a lower portion thereof is open to provide an access opening 8 for the introduction of bags as will later be described.

As with all laminar flow cabinets, a sterile gas, e.g. air, is cleaned by filtering in known manner and is then pumped through screens located upstream of the perforated wall 5 and is arranged to exit through each of the perforations in the wall 5 uniformly across the wall at a steady flow rate. This air flows in known manner from the wall 5 through the cabinet in linear fashion, and exits largely through the opening 8. Any bacteria, dust or other impurities which find their way into the interior of the cabinet will automatically be entrained by the air stream and pass out of the openings 8 & 25. The cabinet has a compartment 11 at its rear, in which suitable electrical and fluid control apparatus such as pumps, filters, heaters, dispensers for chlorine or other sterilising liquids and the like are located, the compartment being separated from the working area 4 by a rear wall 13. The air which exits from the apertures in the wall 5 is pumped through the screens or filters (not shown) which are located in a further compartment 16 immediately upstream of the wall 5. The top of the cabinet is closed off by a cover 17, e.g. of plastics material, and the bottom of the cabinet is defined by a further sheet, e.g. of stainless steel 19. A tray 20 on which batches of bags are unwrapped is supported about sheet 19. An upper part of the front wall of the cabinet is closed off by a transparent sheet 21, the right-hand edge of which is supported by means of a plastics coated tubular steel frame 23. The lower part of the front wall of the chamber between the sheet 19 and the lower edge of the transparent front sheet 21 is open to provide an exit opening 25 communicating with the access opening 8.

Located within the cabinet 1 and within the air flow a source of ultra-violet radiation may be provided, the purpose of which will hereinafter be described.

Also located within the cabinet 1 towards its upstream end is a device 27 for filling plastics liner bags with a fluid material, e.g. milk or another liquid foodstuff. This device 27 has at its lower end a bactericidal chamber in which a de-capping, filling and re-capping mechanism is housed, the whole chamber being fed with a supply of heated chlorinated air or other sterilising agent. If desired, more than one such device 27 may be situated within the cabinet. A filling platform 28 is located beneath the device 27, spaced from the base sheet 19.

Normally, an operator would be located in front of the cabinet and to his right-hand side he would have a carton full of previously sterilised bags, e.g. 5 or , double overwrapped capped sterile liner bags. These bags would have been manufactured, capped, wrapped and sterilised at a location remote from the filling machine. The operator would take a batch of these liner bag-s out of the carton, remove the first overwrapping, i.e. the outer wrapper, and would then insert the batch of liner bags into the work area 4 through the access opening 8. Any germs tending to adhere to the second or inner overwrapping of the batch of bags would tend to be swept out of the work area 4 by virtue of the laminar flow of air through the work area. While keeping the batch of bags within the work area, the operator would then, by inserting his hands through the exit opening 25, remove the second or inner overwrapping from the batch of bags and discard this, leaving the individual sterile bags on the tray 20.

This operation is carried out within the area which may be covered by the ultra-violet radiation. The operator would then take one of the unwrapped bags, place it on the platform 28, and offer up the capped filling and discharge spout to the underside of the bactericidal chamber of the device 27 which would automatically grip the spout. The operator would then remove both hands from the work area 4 so as to operate a safety starting mechanism located on an outer face of the cabinet which would automatically start a decapping, filling and re-capping cycle of the device 27. During this cycle, a predetermined amount of fluid, e.g. milk, would be metered into the liner bag, followed optionally by a jet of inert gas and after re-capping, the spout of the liner bag would be ejected from the underside of the device 27. During all or part of this cycle, a jet of heated chlorinated air or other sterilising agent is sprayed onto the spout, part of which air or sterilising agent is pumped out of the bactericidal chamber and the remainder of which is entrained by the laminar air flow to exit largely from the access opening 8. Once the bag has been ejected from the device 27, it is removed by the operator from the platform through the exit opening 25 and transferred onto a conveyor or into an outer case or other container and is then taken away for subsequent processing.

The operator then offers up a further liner bag to the device 27 and the whole filling operation is repeated until all the bags in the batch on the tray 20 have been filled. The operator then repeats the process with another batch of bags which he takes out of their outer wrapping or container.

It has been found that with the apparatus and method of this invention, a filled liner bag can be obtained which has remained under totally aseptic conditions, from manufacture of the bags and throughout the filling operation. Any germs from the operator's gloves which may be attracted to the filling spout are destroyed or removed, as with known apparatus, by the jet of heated sterile chlorinated air or other sterilising agent associated with the device 27 and any other germs or bacteria which find their way into the work area 4 either on or independently of the bag are carried away by the laminar air flow. Alternatively, or additionally, the germs are destroyed by the ultraviolet radiation. It may be desirable for the operator occasionally to sterilise his gloves.

Although it is preferred that the upper portion of the front wall be closed off by the transparsnt sheet of material 21, this is not essential. Furthermore, although it is preferred that the laminar gas flow in the work area 4 be achieved by blowing air through the cabinet, it is envisaged that it could be achieved by a combination of blowing and sucking.

It will also be appreciated that the shape of the work area 4 and the general layout of the cabinet could be slightly different from that illustrated and described.

Although a manual operation has been described, it is envisaged that the whole operation can be carried out in a semi or fully automatic manner as follows:The bags may be manufactured in a continuous preS3007 perforated web vzhich is fan folded and the complete batch of bags over-wrapped and sterilised. The overwrap may be removed from the batch of bags within a sterile area adjacent to the cabinet 1 and the leading bag of the web fed by the operator into an enclosure where the outside of the bags are re-sterilised by irradiation or chemical means and are then fed into the work area 4. When the individual bags have been filled and re-capped, they may be separated from the continuous web of bags at the pre-perforated section and removed automatically from the work area 4.

Claims (19)

1. A method of aseptically packaging fluid material comprising capping a plurality of liner bags, forming them into a batch, wrapping the batch of bags, and then sterilising the wrapped batch of bags, and subsequently, at a filling station, removing a wrapping from the batch of liner bags, feeding the batch of bags into a laminar flow cabinet through which a sterile gas is caused to pass, and presenting individual bags to a de-capping, filling and re-capping station located within the laminar flow of gas, so that the bags are individually de-capped, filled with a predetermined amount of fluid material and re-capped by the de-capping, filling and re-capping device, all under totally sterile conditions, removing said filled re-capped bags from the cabinet, and placing said filled bags in an outer case or other container.

2. A method according to claim 1 wherein the bags are removed from the cabinet through an exit opening in a front wall of the cabinet.

3. A method according to claim 1 or 2 including the steps of manufacturing the liner bags remote from the filling station, and transporting the wrapped sterile bags to the filling station.

4. A method according to claim 1, 2 or 3 wherein the bags are double wrapped after manufacture, an outer wrap is removed from the bags by hand, and the still inner wrapped bags are fed in batches into the laminar flow cabinet, whereupon the inner wrapping is removed from the bags within the cabinet so as to maintain the bags in a sterile condition.

5. A method according to claim 4 wherein the inner wrapping of the bags is removed within an area inside the cabinet which is covered by ultra-violet radiation.

6. A method according to claim 1, 2 or 3 wherein the bags are manufactured in a continuous pre-perforated web which is fan folded, and wherein the wrapping is removed from the bags within a sterile area adjacent to the laminar flow cabinet.

7. Aseptic liner bag filling apparatus for filling pre-wrapped, sterile liner bags comprising a laminar flow cabinet, means to cause a sterile gas to be passed through the cabinet in a laminar flow, a de-capping, filling and re-capping device located within the cabinet, an access opening in a wall of the cabinet through which liner bags which have not been manufactured within the cabinet may be Introduced into the cabinet, so that their capped filling spout may be offered up to said device, which automatically de-caps the bags, fills them with a predetermined amount of fluid and re-caps them, and an exit opening in the cabinet through which said filled and re-capped bags may be removed from the cabinet for subsequent insertion within an outer case or other container.

8. Aseptic filling apparatus according to claim 7 wherein the exit opening is in a front wall of the cabinet.

9. Aseptic filling apparatus according to claim 7 or 8 and including a source of ultra-violet radiation within the cabinet so located that an inner wrapper may be removed by hand from the bags while being subjected to said ultra-violet radiation.

10. Aseptic filling apparatus according to claim 7, 8 or 9 wherein the laminar flow cabinet is of generally rectangular cross-section in the direction of gas flow through the cabinet, there being a perforated inlet wall at one end of the cabinet through which filtered sterile gas is introduced at a regular rate over the full cross-sectional area of the cabinet.

11. Aseptic filling apparatus according to claim 10 wherein at least a lower portion of the end of the cabinet opposite the inlet wall is open to provide the access opening.

12. Aseptic filling apparatus according to any one of claims 7-11 wherein the laminar flow cabinet has a tray in a lower region thereof on which bags to be filled are removed from the inner wrapper and stored at a downstream end of the work table.

13. Aseptic filling apparatus according to claim 10 wherein the exit opening extends the full length of the cabinet and is provided in a front wall of the cabinet, just above the cabinet base, the opening being deep enough to permit an operator to reach in to remove an over-wrapper from the bags on the tray and to allow the operator to present individual bags one at a time to the de-capping, filling and re-capping device and to allow the operator subsequently to remove the filled bags from the cabinet and place them in an outer case or other container.

14. Aseptic filling apparatus according to any one of claims 7-13 wherein, apart from the exit opening, the front wall of the cabinet is closed by a transparent sheet of material.

15. Aseptic filling apparatus according to any one of claims 7-14 wherein the cabinet also includes at least one further closed compartment in which filters and various control apparatus are housed, but which is separated off from the laminar air flow chamber.

16. Aseptic filling apparatus according to any one of claims 7-15 and including means for feeding bags automatically into the cabinet after their wrappers have been removed within a sterile area adjacent the cabinet, means for filling them and means for removing them automatically from the cabinet.

17. Aseptic filling apparatus substantially as hereinbefore described with reference to the accompanying drawing.

18. A method of aseptically packaging fluid material according to claim 1, 2, 3 or 4 wherein the bags are unwrapped in a sterile area adjacent to the cabinet and are then fed automatically into the cabinet, are automatically filled and are subsequently removed automatically from the cabinet.

19. A method of aseptically packaging fluid material in liner bags substantially as hereinbefore described with reference to the accompanying drawing.