AU616165B2

AU616165B2 - Packaging methods and packages

Info

Publication number: AU616165B2
Application number: AU10665/88A
Authority: AU
Inventors: Bernard John Bourke
Original assignee: Trigon Packaging Systems NZ Ltd
Current assignee: Trigon Packaging Systems NZ Ltd
Priority date: 1987-01-22
Filing date: 1988-01-20
Publication date: 1991-10-24
Anticipated expiration: 2008-01-20
Also published as: NZ219039A; AU1066588A; GB8801292D0; GB2200091B; GB2200091A

Description

COMONEAL11OF AUSTRALIA Pate', .s Act 1952 UE~IGQN F'A~QKAGINQ SYSrEr1S (142-1) IL ]r'4 190BXD S COMPLETI: SPECIFICATI ON FOR~ THE INVENTION ENT!TLED:- "PACKAGING METHODS AND) PACKAGES" The~ fol-tow4ing stteniint, is- a full desoripLLon of this 1rnVmr1-it i n uizcJuc ing th(- best. me-thcod of do'o'urig .it know 4 to Wt,:- This invention concerns a vacuum package.

The invention will be described with reference to vacuum packaging of meat but those working in thio technology will appreciate that the invention is applicable to other foods or articles which are vacuum packed. Packers of multiple portions of the same cuts of meat for retail and wholesale now make greater use of vacuum packs whereas once it was common only for bacon and specialty meats.

The packs may be 300 x 200 and may contain for example several steaks. These are sealed in a vacuum packing machine using the following method. A bag the size described above is supplied ready sealed on three sides. The bag is filled and loaded into a vacuum chamber with the mouth of the bag lying between a pair of sealing bars or similar closure devices which after the bag is evacuated are activated to seal the pack on the fourth side.

A vacuum pack for bony cuts for example chops may have to endure handling in a butchers shop, supermarket or restaurant freezer. It is not uncommon for the sharp corner or point of a chop bone to pierce the film of the pack and destroy the vacuum.

This leads to the incursion of air and the build up of a telltale ice layer which spoils the appearance of the meat. This may lead to unsaleability even though the meat may still be palatable and in a edible condition, or can cause contamination.

25 Puncture occurs for several reasons. Firstly, because the film loses some of its yield capability as the storage temperature falls. Secondly, the vacuum ensures that the film is already tightly drawn around the outer surface of the meat including any protruding bone. Loin, neck and rump chops are particularly likely to present bony protrusions in this respect.

Thirdly, the force available for penetration is increased by the stacking of meat packs one on top of the other in a freezer coupled with the herdness of the contents and the tendency of salespersons to jam the packs where ever they will fit.

A method aspect of this invention provides a method of i "t" :i) r i i 1 r J packaging a product comprising the steps of enclosing said product within an inner bag having an opening at a common end to an outer bag, said bags either sharing no common edge seam or else at lease an edge seam opposite the bags' openings, followed by closing the package such that at least the inrer bag is sealed under vacuum and the space between said bags remains open to the atmosphere.

The inner and outer bags may be made separately and one inserted inside the other either before filling or after filling.

Another alternative is to have the inner bag se;aled along the sides and bottom, and the outer bag sealed only at the sides forming a jacket.

Another method aspect of the invention provides a method of packing an article in a pack as described above comprising placing the article in the inner bag, evacuating the pack in a vacuum chamber and sealing the four film plies constituting the common side or opening of both bags while within the chamber.

The final seal may unite the two plies which constitute the inner bag. Alternatively the final seal may unite all four plies. When the latter method operates, the two outer plies are perforated to allow air ingress between the inner and outer bag so that the outer plies will separate from the plies making up the inner bag so that some sliding movement between the plies is possible despite their being united along the remainder of their 25 common perimeter.

A product aspect of the invention provides a vacuum package comprising a first bag having an opening and a plurality of apertures, a second bag contained within the first bag and having an opening and a product contained within the second bag wherein the openings are closed along a single common margin and the second bag is evacuated and connected to the first bag only at the said margin, space between the bags being open to atmosphere through the apertures.

The inner bag may protrude from the mouth of the outer bag so that only the protruding border is sealed after filling and 3 j i.: I r -1 1 I vacuum treatment. One bag is preferably of a film which is selected for tear strength and pliability at freezer temperatures or a compromise between these properties while the other bag film may be thinner and have a glossy surface to provide slip between the first bag and the second bag and secondly, between the three bags and other external contact for example, other packs. Either or both of the bags may bear print.

Embodiments of the present invention are now described by way of example only with reference to the accompanying drawings in which: Figure 1i: is a diagrammatic section of a vacuum package in accordance with the present invention after loading, Figure 2: is a diagrammatic section of the vacuum package of *Figure 1 with the open ends thereof having been nipped 0I by a clamp, and S Figure 3: is a diagrammatic section of the clamped bag of Figure 2 ft+t r the inner bag has been evacuated, and i Figure 4: is a perspective view of an evacuated and sealed package in accordance with one possible embodiment of 20 the present invention, and Figure 5: is a perspective view of an unsealed pack in accordance with another embodiment of the present invention, and Figure 6: is a perspective view of the pack of Figure 5 after sealing.

Firstly, with respect to Figures 1 to 4 of the drawings, in accordance with one possible embodiment of the present invention bags 1 and 1.1 of known construction namely rectangular polythene bags are filled with meat cuts 2, the inner bag 1 then being H evacuated and a common opening sealed.

S*

a 0 The inner bag 1 is loose within the outer bag 1.1 and the open end 4 of the inner bag may, at least initially, extend beyond the equivalent opening 5 of the outer bag 1.1.

TI The inner bag 1 is placed within the outer bag 1.1 and filled with product such as meat cuts 2 as illustrated by Figure 1. The openings 4, 5 of the bags are then clamped by clamp 6 of a vacuum forming apparatus (not shown) which may be a chamber-type apparatus or a non-chamber apparatus such as the CORR-VAC machine manufactured by M-Tek of the U.S.A.

Figure 3 illustrates a package formed from the two bags 1, 1.1 in which the inner bag 1 has been evacuated using a vacuum probe 7 which extends between clamp 6, and the openings 3 sealed by seal bars (not shown) associated with the clamp 6.

After evacuation the inner bag 1 is closely formed about the meat cuts 2 whilst the 10. outer bag 1.1 is a lose fit on the inner bag 1 with the bags being united about one edge, that is, the opening 3.

The outer bag 1.1 is provided with a plurality of apertures 7 therein which may be along one edge of the outer bag or elsewhere (not shown) so that the air space between the outer bag 1.1 and the inner bag 1.1 is subject to atmospheric T conditions. This means that the outer bag 1.1 is able to slip with respect to the inner bag 1 with the risk of a puncture of both of the plies of the bags being substantially reduced.

Figures 5 and 6 of the drawings illustrate a possible aiternative construction for a package in accordance with the present invention. The bag 8 is made of four super-imposed rectangular plies of film. The two inner plies 9, 10 form the inner bag 11 while two outer plies 12, 13 form the outer bag 14. All the plies are joined iby a continuous seal 20 around the three sides as shown but the inner plies are longer than the outer plies leaving a mouth 21 to which the bag can be filled. The bag is evacuated and then sealed in the same manner as previously described, the final closing being achieved by establishing seal 22 as shown in Figure 6.

Aspects of the present invention have been described by way of example only and it would be appreciated that modifications and additions thereto may be made without departing from the scope of the invention as defined in the appended claims.

Claims

1. A vacuum package comprising a first bag having an opening and a plurality of apertures, a second bag contained within the first bag and having an opening and a product contained within the second bag wherein the openings are closed along a single common margin and the second bag is evacuated and connected to the first bag only at the sai.d margin, space between the bags being open to atmosphere through the apertures.

2. A package as claimed in claim 1 wherein the said apertures are located in a side margin of the first bag.

3. A package as claimed in claim 1 or claim 2 wherein the bags are each formed of a material having different characteristics from the material of the other bag.

4. A package as claimed in claim 3 wherein the material of one of the bags is thinner than the material of the other bag.

A package as claimed in claim 4 wherein the thinner material is provided with a glossy surface facing the material of the other bag so as to provide slip between the bags.

6. A vacuum package substantially as hereinbefore described and as illustrated by Figure 4 of the accompanying drawings. DATED THIS Seventh DAY OF August, 1991. TRIGON PACKAGING SYSTEMS (NZ) LIMITED BY PIZZEY COMPANY PATENT ATTORNEYS a.. p. I**