US 3360382 A
Description (OCR text may contain errors)
. Dec. 26,1967 H. B. MILLER METHOD OF PACKAGING MEAT Filed Dec. 27, 1965 INVENTOR flag/v0 B. M11154 J 4 4 004w ATTORNEYS United States Patent O 3,360,382 METHOD OF PACKAGING MEAT Harmon B. Miller, Atlanta, Ga., assignor to Scientific- Atlanta, Inc., Atlanta, Ga., a corporation of Georgia Filed Dec. 27, 1965, Ser. No. 516,295 3 Claims. (Cl. 99-174) This is a continuation-in-part of my previous application Serial No. 384,846 filed July 24, 1964.
The present invention is concerned with a package and a method of packaging and, more particularly with'packaging in containers of rigid, transparent or translucent plastic of products such as sliced luncheon meats and, other perishable goods, especially with gas flushing of the contents.
In the aforesaid patent application, there is described a package comprising a hollow receptacle or cup of rigid plastic material having a bottom, sides and a laterally extending sealingflange at the upper edges of the sides. An upright lip extends from at least a part and preferably all of the outer edge of the sealing flange. The package is closed by a lid which overlies the cup and the flange and has a tab which projects beyond the lip. The tab rests on the lip when the lid initially is placed on the cup so that the lid is propped up and permits withdrawing of air from the cup and replacing it with a gas. The connection between the tab and the rest of the lid is scored or otherwise constructed so that, when the package is closed by pressing the lid against the flange, the tab is bent out of the way to fit within the lip. Ordinarily, the lid is heat sealed to the cup. As will be appreciated, the lip also is useful to retain the lid in place after breaking the seal, so that the package may be opened and reclosed by the purchaser.
In many cases, the reclosable feature is not needed, or can be provided by a pressure-sensitive adhesive. In such cases, it is desirable to omit the lip to reduce costs and facilitate handling the cups. However, the lip also is used in connection with the gas flushing to keep the package partially open for ingress and egress of gas and air. Therefore, it could not be omitted if the package is to be gas flushed.
In accordance with the present invention, a new type of lid is used which makes it possible to omit the lip. Briefly stated, the lid is bowed outwardly from the cup so as to define a kind of tunnel between itself and the cup. The bowed lid is placed over the cup and maintained bowed outwardly during gas flushing. Then it is sealed to the cup.
The manner in which the invention is used will be understood better by considering the following description of its preferred embodiment and referring to the drawing in which:
FIG. 1 is a perspective view of a package being flushed with gas,
FIG. 2 is a side elevation of a closed package; and
FIG. 3 is a vertical cross section of a closed package on larger scale than FIG. 2, some parts being shown in elevation.
As seen in FIG. 3, the package comprises a cup I, having a bottom 2, sides 3 and a continuous flange 4 extending laterally from the upper edges of the sides and continuously around the cup. The cup may be constructed of a transparent plastic such as polystyrene, polyvinyl chloride or the like. However, it also may be formed from other relatively stiff or rigid materials such as cardboard or aluminum foil.
The lid 5 is initially placed over the cup and rests on the flange on two sides. In the form illustrated, it is made of metal foil 6, such as aluminum foil, which may be laminated to relatively stiff paper 7 and undercoated with heat sealing plastic 8. A metal foil such as aluminum, having a thickness of 0.3 to 1.0 mil laminated to paper having a thickness of 4 to 10 mils is a preferred material because of the gas barrier properties of the metal foil and its ability to retain its shape if bowed. That is, once lids of this type are bowed they will stay bowed until pressed flat again. The same effect may be accomplished with plastic or paper lids by scoring them, for example along a series of parallel lines.
The term bowed is used to define the relationship between the lid and the opening into the cup. That is, any arrangement by which an inner portion of the lid is displaced generally outwardly from the opening of the cup while other portions of the lid are held to the cup will be satisfactory. The exact shape of the lid will depend on. the shape of the opening into the cup. As can be seen from the drawing, a preferred type of cup is a hollow receptacle having a flat flange continuously around its rim. In such case the lid maybe arched outwardly in a simple curve as shown in FIG. 1. However, other arrangements can be used for other types of receptacles and will be understood to be within the scope of the invention.
In the embodiment illustrated in FIG. 1, it can be seen that the bowed lid forms a kind of tunnel indicated at 9 over the package. Gas flushing may be accomplished by approximately simultaneously applying suction and gas pressure at the opposite ends of the tunnel. The gas and suction may be supplied by nozzles 10 and 11 directed laterally towards the ends of the tunnel 9 as shown, or, for example, in the apparatus described in the US. patent application of Grant E. Allen, Jr., et a1., Serial No. 498,896, filed October 21, 1965, now US. Pat. No. 3,334,- 602.
A strong vacuum is not required, because removal of air is accomplished principally by a sweeping action. That is, gas under pressure pushes air toward the opposite end of the package. As the gas pressure increases, it is possible to reduce the vacuum, and it is even possible to omit the suction entirely if there is sufficient gas pressure. However, this would waste gas and therefore is not preferred.
The tunnel formed by the lid greatly expedites gas flushing and reduces cost. That is, it provides a kind of flushing chamber to minimize escape of the gas to the surrounding atmosphere. It also guides or deflects the gas so that it moves toward the opposite end, forcing air ahead of it and expelling the air from the package.
Ordinarily, the other gas is an inert gas such as carbon dioxide or nitrogen. However, it has been proposed that oxygen is desirable for preserving the freshness of certain products such as fresh meats and vegetables. It will be recognized that the present package may be used just as effectively for packaging with oxygen as with any other gas.
After gas flushing, the package is closed by forming a gas-tight seal between the lid 5 and the flange 4. This may be accomplished by heat sealing or adhesive. The term heat sealing refers therefore to formation of a bond by application of heat. Numerous procedures are known to the art including softening and rehardening of thermoplastic materials such as polyethylene, curing of heat activated adhesives and the like. However, the method of sealing itself forms no part of the present invention, any suitable method for producing a connection between the lid and the cup by application of heat, preferably a gastight connection, being suitable.
The bowed lid provides another important advantage, i.e. in the appearance of the package. That is, when the edges of the lid are sealed to the cup, the pressure of the gas urges the lid outwardly, reducing the chance of wrin- 0 kling and giving the appearance of a full package. If the commodity packaged is not a liquid it may in fact fill the cup above its rim. The invention provides other advandescribed and illustrated is intended, the invention having a scope as defined in the appended claims.
I claim: 1. A method of packaging sliced luncheon meat and other perishable goods with a gas other than air in a con- I tainer comprising a cup having a compartment surrounded by a sidewall, an outwardly extending flange on the upper rim thereof and a bottom, said method comprising the steps of placing said goods in said compartment, placing a closing lid on said flange over said goods, said lid being bowed outwardly so as to provide two openings on opposite sides of the cup between said lid and said rim whereby a tunnel is defined between said cup and said lid, introducing said other gas under pressure at one of said openings and into said tunnel while withdrawing air from said tunnel through said oppositely located opening, whereby said tunnel channels theflow of air and said other gas between said openings, and then forming a gas-tight seal between said lid and said flange to retain said other gas in said package.
2. A method as set forth in claim 1 wherein said gas is oxygen and said goods are fresh meat.
3. A method as set forth in claim 1 wherein said gas is oxygen.
References Cited UNITED STATES PATENTS '8/1 935 Young 99189 X 2,054,492 9/1936 Young 5322 2,412,167 12/1946 Minaker 5312 2,623,826 12/1952 Grinstead 99-174 2,763,107 9/1956 Day et a1. 53-7 2,870,954 1/1959 Kulesza 99174 X 3,012,894 12/1961 Nagel 99-174 X 3,117,873 1/1964 Bartels et al. 99171 FOREIGN PATENTS 148,690 10/ 1952 Australia.
HYMAN LORD. Primary Examiner.