US 3502487 A
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J- T. BYRD March 24, 1970 FOOD PRESERVING PACKAGE AND METHOD 0F CLOSURE Filed. July 15, 1968 INVENTOR. J'AME'J 7- Bww W/ A amvr United States Patent 3,502,487 FOOD PRESERVING PACKAGE AND METHOD OF CLOSURE James T. Byrd, Burbank, Calif. (1269 W. Baker St., Apt. B, Costa Mesa, Calif. 92626) Filed July 15, 1968, Ser. No. 744,766
Int. Cl. B65b US. Cl. 99-171 Claims ABSTRACT OF THE DISCLOSURE In particular, there are foods that can be advantageously packaged and merchanized in flexible tubular sack-like containers. In the past, such food packages have been sealed in various ways, making provision for the escape of vapors and fluids which are liberated when cooking said foods with the entire package immersed in the heat of an oven or in a cauldron of boiling water. In any event, problems arise from the nature of foods which contain moisture and which very often involve loose particles of food stuifs including spices, and it is these 'vapors, liquids and various particles that interfere with the usual seal. For example, the usual seal is quite often a a labyrinth which provides a tortuous passage, or the usual seal might be a folded constriction of the package wall. In practice, the prior art passages tend to and in fact do become clogged and the constricted folded parts become separated, and all to the end that the vent and the seal often become inoperative. That is, a vent clogged with food particles is inoperative and could result in a bursting of the package when cooking heat is applied; and a package with food particles separating the folded parts will not reliably seal. Consequently, it is likely that a clogged package will burst when subjected to boiling temperatures, and it is likely that the separated package parts will permit the drawing in of contaminating fluids when cooking temperatures are removed. In other words, the physical principles involving expansion and contraction of fluids is involved, it being a primary object of this invention to permanently encase a package unit of food within a membrane which is not subjected to bursting pressures, and which does not draw in any surrounding contaminating matter.
In view of the requirements for venting and expulsion of excess vapors and/or fluids from within the package, I have provided a package of the simplest form and which nevertheless provides adequately for both venting and sealing out of contaminants by means of a check valve action, and all of which is achieved without added parts,
without additional steps in effecting a closure, and all of which is inherently operative without special attention to expell and prevent re-entry of fluids.
It is still another object of this invention to provide a food package with a seal that is enhanced by the presence of food liquids. Especially, for example, fats and the like such as suet of meats become more liquid as heat is applied, and conversely when cold, and it is these substances which enhance the seal of the present invention, as will be hereinafter described.
It is also an object of this invention to provide a vent structure per se which receives loose food stuffs and spice particles, as mentioned above, and which discharges the same in the event that any such stufi's or particles enter into said vent. Thus, provision is made to protect the vent and so that particles do not lodge therein.
The various objects and features of this invention will be fully understood from the following detailed description of the typical preferred forms and applications thereof, throughout which description reference is made to the accompanying drawings, in which:
FIG. 1 is a perspective view of a typical food package embodying the features of the present invention.
FIG. 2 is an enlarged front view of the package.
FIG. 3 is an enlarged detailed fragmentary and sectional view taken as indicated by line 33 on FIG. 1.
'FIG. 4 is a typical cross-section of the apparatus employed to effect the closure of the package shown in FIGS. 1 to 3, and FIG. 5 is an enlarged fragmentary view taken as indicated by line 55 on FIG. 4
The package unit P is shown in FIGS. 1 and 2 of the drawings and wherein there is contained a portion of food F. For example, a prepared Mexican food such as a tamale, burrito or enchilada is to be contained, or any like prepared food portion as circumstances may require. In accordance with the invention there is a seal S, and advantage is taken of foods which contain natural oils, grease or suet to cooperate with said seal, and in the event that oils, grease or suet is not present therein then the same is applied as an additive. However, in a portion of food containing meats, it has been found that sufficient liquid exudes from the suet for purposes hereinafter described; and if and when circumstances require a liquid such as oil or grease is supplemented at least locally in the vicinity of the seal S. It is to be understood that the shape of the portion P can vary widely, a typical proportioning being shown and which involves an elongated body of food having some depth and substantial width.
The portion of food F is contained within a wall 10 of material that is closed around said portion so that a package unit P is established. The wall 10 is essentially an elongated tubular element that is closed at its opposite ends, having what I will term a bottom and top closure 15 and 20 respectively. In practice, the wall 10 is made of a soft and pliable plastic material such as Mylar, as it is manufactured by Du Pont, a poly ester plastic that can be subjected to baking and boiling temperatures without adverse effect. The Wall 10 of a tube form can be an integral tubular form or it can be assembled of flat sheet and secured in tube form along one or more longitudinal seams. In any case, the seam joinder and bottom and top closures can be facilitated by the lamination of a face 12 of polyethene onto the inside of the plastic sheet, for the purpose of bonding the wall in order to form and to close the package. Said bonding is accomplished in the usually accepted manner by the application of suitable heat to and pressured engagement of the parts to be joined. In practice, it is most practical to construct the package Wall 10 of two coextensively related panels of pliable and transparent Mylar film of one mil thickness, and with the polyethene faces 12 in opposition for bonded engagement where required. As shown, the two side margins 13 and 14 are continuously bonded, and the bottom closure 20 continues between the said side margins.
The above described side margins and bottom closure are continuously bonded so as to establish an impervious joinder between the two coextensive panels of plastic material. Adjacent the bottom closure 20 there is a cut 18 or nick in the edge of the bonded material, and there is a point indicated where tearing can be started at said cut 18. In practice, there can be two opposite cuts 18, to initiate tearing through the wall of the package in order to open the entire bottom thereof. As shown, the bonded areas are of substantial width and are established by pressuring together of the two panels in the presence of heat.
From the foregoing it will be apparent that it is a simple matter to provide a rectangular sack of tubular crosssection that is open at the top end for the reception of food contents. And, it is a simple matter to insert food contents into such a tubular sack. However, the satisfactory enclosure of the food portion F in the package unit P is quite unobvious as it is practiced in its simplest and most practical form that will now be described. Firstly, the width of bonding is substantial as is above described, and in the preferred form is approximately one quarter inch wide. Secondly, the side margins 13 and 14 continue into the bottom closure 20, the bonding being substantially the same and continuous throughout all three sides thus far considered. Thirdly, and in accordance with the invention, the top closure 15 is also of approximately one quarter inch width and it too is continuous with the side margin bonding 13 and 14. Thus, a complete and continuous enclosure can be easily attained. However, a vented seal S is provided in the top closure 15 by the provision therein of an interruption of the bonded connection between the two panels that are brought contiguously together by means of said bonding through the application of heat and pressure the same as above described.
The said interruption of the bonded connection that forms the closure 15 is best illustrated in FIG. 3 where :he bonded area is indicated as a cross-hatched solid naterial that has been fused together by means of heat ind pressure. In this instance, it is the opposed poly- :thene faces 12 which fuse together along the top margin )f the package, in an area of approximately one quarter nch width. In accordance with the invention the said .nterruption is established by a discontinuity of the bondng intermediate the two side margins 13 and 14 and :haracterized by the termination of the bonding along apposed and outwardly divergent lines 21 and 22. The ines 21 and 22 are preferably straight lines at which he panels are joined together and between which the )anels are loose and disconnected. Further, the inner :xtremity of the lines of joinder 21 and 22 are spaced, For example /8 inch, apart and diverge outwardly at an ncluded angle of approximately As a result, the iexible and pliant walls of material between the lines of oinder 21 and 22 are free to separate to increasingly Form a channel for the passage of fluids therethrough.
In accordance with the present invention it is of prinary importance that the seal S above described act as a enting check valve to permit exhaust of fluid from and o prevent re-entry of fluid to within the otherwise en- :losed interior of the package P. As is pointed out above, t is common to construct a package of plastic fused together along its circumferential margins. However, the ormation of a seal S having both the venting capability ind check valve function has been impractical if not imiossible with prior art packaging where loose granular iarticles of food and the like are involved. That is labyinth and folded structures have not prove to be satisactory, and it is the disadvantages such as clogging and eaking that the instant seal S overcomes. In this instance t is the spaced and divergent lines of joinder 21 and 22 hat renders the invention operative, particularly in the resence of solidifying meat juices. The outward flare of he passage between the lines 21 and 22 not only induces seal under the influence of exteriorly applied atmosiheric pressure, but also promotes the discharge substance taI'tlClGS while preventing re-entry thereof. For example, .ny substance particle which might be forced by fluid presure to exude between the lines of joinder 21 and 22 at heir inner extremities where they are proximately closest vill then freely pass through and from the ever widening iassage formed between said lines. Most important is th prevention of exposed substance particles returning through the passage, and due to the divergence of said joinder lines it is virtually impossible for a particle to return through the passage once it has cleared the innermost restriction thereof. Consequently, any stray particles that enter the vented seal S will inherently work through the same and be expelled from the package and in no case will such particles return after being exposed outside the package.
In FIGS. 4 and 5 of the drawings I have shown the method and apparatus which forms and establishes the seal S hereinabove described. As shown, there are two relatively movable bars 30 and 35 that remain parallel with each other and which alternately separate and come together into pressured engagement. And, as is usual practice at least one of the bars 30 or 35 is heated by means of a heating element 40. Also, the engageable faces 31 and 36 of the bars 30 and 35 are, in accordance with the invention, convexly crowned for the progressive displacement of any substance that might otherwise be entrapped Within the sealed area. Said convex crown is, in practice, imperceptibly slight so that engagement of the desired sealing area is coextensive, or nearly flat, taking advantage of the compressibility of the materials involved. It will be apparent that the heat and pressure can be applied by heating one or more of the bars and by moving the bars together by suitable means (not shown).
The bar 30 is heated by the element 40 and its nearly flat pressing face 31 is in opposition to the bar 35. The latter bar 35 has a pressing liner 37 which presents the nearly flat pressing face 36, said liner being a thin layer of synthetic heat resistent and resilient material such as Teflon, while the former bar 30 is preferably metallic so as to conduct heat from the element 40 and to the margin of the package engaged between faces 31 and 36. In accordance with the invention one or both of said bars is interrupted, and as shown the bar 35 is interrupted in the configuration of the channel that is established by lines of joinder 21 and 22. To this end the face 36 is grooved or separated at 32 by angularly related walls 33 and 34 that correspond to said lines 21 and 22 respectively, the liner 37 following into the groove or separation. Thus, the inside edge 37 of the bar 35 is separated A5 inch at the walls 33 and 34, while the said walls diverge at approximately 10 toward the outside edge 38. The walls 33 and 34 are of substantial depth being normal to the plane of the face 31. As a result, heat and pressure is entirely eliminated between walls 33 and 34, and so that there is virtually no bonding intermediate the walls 33 and 34, and consequently the panels of the package remain free in that area.
From the foregoing it will be apparent that the use of the apparatus comprising the two relatively movable bars 30 and 35, and at least one of which is interrupted by angularly related walls, results in a vented and self-clearing seal when heat and engaging pressure are applied with the heat bondable panels engaged therebetween. The seal at closure 20 is consequently formed to have the divergent character above referred to with the contiguous and pliable panels adapted to vent and as well to prevent reentry of fluids and solids. Consequently, excess fluids are readily expelled when the package P is manipulated and/ or subiected to heat, and in the event that loose solids enter the passage between lines 21 and 22 they do not clog or jamb therebetween and are free to be expelled. On the contrary, however, when expelling action is removed and/or when the package is cooled the fluids and solids do not re-enter, and as fatty food substances consolidate there is an adhesion of the contiguous panels at the seal in addition to the engagement inherent in the application of external atmospheric pressures, and all of which etfectively closes the seal.
Having described only a typical preferred form and application of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but
wish to reserve to myself any modifications or variations that may appear to those skilled in the art.
Having described my invention, I claim:
1. A package and vented closure therefor including, an open ended sack-like container comprised oftwo opposed panels of flexible and pliant sheet material, said container being an initially closed envelope except for said open end and the sheet material :being bondable together at said open end, and a closure for confining contents within said container and comprising the bonding together of opposed marginal portions of the panels at said open end with a marginal area of attachment having a substantial marginal width and having a passage through said marginal area and definedby two straight and outwardly divergent and spaced lines of joinder with the sheet material therebetween free and flexible to alternately separate and close.
2. The package and closure as set forth in claim 1 and wherein the two sheets of material are separate and initially attached at all margins thereof except for said open end, the panels at said open end being brought contiguously together for said closure.
3. The package and closure as set forth in claim 1 and wherein the two sheets of material are flat and coextensive and initially attached at all marginal areas thereof except for said open end, the opposed marginal areas of the panels at said open end being brought contiguously together for said closure.
4. The package and closure as set forth in claim 1 and with a viscous liquid entered between the said lines of joinder to assure effect of the sealing function.
5. The package and closure as set forth in claim 1 and which advantageously employs the congealing characte of a viscous liquid of the contents to assure effect of the sealing function by adhesion of said free sheet material intermediate said lines of joinder.
References Cited UNITED STATES PATENTS 2,584,632 2/ 1952 Southwick 22962.5 2,696,342 12/1954 Toborg 22962.5 3,311,287 3/1967 Long et al. 229-53 2,807,550 9/1957 Zarotschenzell et al. 99174 2,963,375 12/1960 Allen 99171 3,027,261 3/1962 Samara 99-171 DAVID M. BOCKENEK, Primary Examiner U.S. Cl. X.R.