US 2986319 A
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Description (OCR text may contain errors)
May 30, 1951 c. R. BIERMAN x-:TAL 2,986,319
VENTING CONTAINER AND METHOD OF' MAKING SAME Filed Oct. 2. 1957 FIG.|
United States Patent O vEN'rING CONTAINER AND METHOD oF MAKING SAME Clarence R. Bierman, Barrington, and Lehman E. Hoag, Cary, Ill., assignors to American Can Company, New York, N.Y., a corporation of New Jersey Filed Oct. 2, 1957, Ser. No. 687,699
3 Claims. (Cl. 229-55) The present invention pertains to a container particularly constructed to permit the release of pressure producing gases `from inside a container and the method of making such a container. More particularly, the invention pertains to an end seam construction whereby pressure producing gases present within an otherwise hermetically sealed container may be vented through this end seam and to the method of making same.
For economy reasons, the body of many containers is made of a fibrous material, i.e. paper, having a moisture and gas proof interior coating to prevent attack and weakening of the fibre by the product. As a general rule, a metal-to-papcr end seam formed by crimping a metal end onto a paper body is not hermetic. However, all or part of the interior coatings used on this type of container body are often sutliciently plastic or deformable to form, in effect, a sealing gasket in the seam thereby making the finished can hermetic.
With certain products, a hermetically sealed can is of no consequence and may even be desirable. With certain types of gas releasing products, however, the increase of internal pressure in a hermetically sealed container is detrimental not only to the container, which is not constructed to withstand such increased pressure, but also to the product packed therein.
A particular example of packed products wherein an increase of internal pressure in the package is undesirable is the packaging or canning of raw or uncooked biscuit dough. The raw biscuit dough, after packaging in the container, liberates carbon dioxide gas. At the same time, the raw dough expands or rises. If the envolved carbon dioxide and other gases present in the container are not vented, the increase of internal pressure restricts the desired expansion or rising of the biscuit dough causing it to be unmarketable; and may cause bursting of the container.
It is, therefore, an object of the instant invention to provide a container adapted to withstand a certain amount of internal pressure and at the same time to permit venting of pressure-producing gases from the interior thereof.
Another object is to provide a container wherein the gases generated by uncooked biscuit dough packed therein may be vented to permit rising of the dough.
Yet another object is to provide a venting container which is simple and easy to manufacture and assemble.
A further object is to provide a method for making a venting end seam for a container.
Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.
The above and other objects of the present invention are obtained by providing at least one end seam of a container with a discontinuous lining between the body of the container, including any interior coating thereon, and the end attached thereto to provide leak passages through the seam. This construction is obtained by enclosing with- 2,986,319 Patented May 30, 1961` 2 in the end seam of the container during its formation a brittle, frangible or friable lining compound which fractures or crumbles during the double seaming of the end onto the body.
Referring to the drawings:
Figure 1 is a side, elevational view in perspective of a finished container constructed according to the present invention;
Fig. 2 is an enlarged, schematic view showing the application of the lining compound to the can end;
Fig. 3 is an enlarged, sectional view with parts broken' away showing joining of the can end carrying the frangible or friable lining compound to the can body;
Fig. 4 is an enlarged, sectional view with parts broken away showing the double seaming of the can end onto the can body; A
Fig. 5 is an enlarged, sectional view with parts broke away of the finished end seam showing the placement and discontinuous nature of the lining.
As a preferred or exemplary embodiment of the present invention, Fig. 1 illustrates a can body 9 having a longitudinally extending lap side seam 10 and metal end closures 11, 12 joined to the can body 9 by means of end or double seams 13, 14. The can body 9 illustrated is formed from a brous material such as paper, and has a wax-like, moisture and vapor proof interior coating 15 covering at least the entire length of the side seam 10. vlf the wax-like interior coating covers only the inside of side seam 10, the remainder of the inside of body 9 is covered by a moisture and vapor proof interior coating (not shown) such as aluminum foil. Although the preferred embodiment can body 9 is illustrated as being iibre, it should be understood that the present invention is adaptable to container bodies composed of other materials such as metal provided their interior is coated in whole or in part with a deformable or plastic coating capable of forming a hermetic seal in the end seam.
For the purpose of the following description, reference will be made only to the top end seam 13. However, it is to be understood that the bottom seam 14 may have a venting construction identical with that of the upper end seam 13 or may be different as desired. l
End seam 13 (Fig. 5) comprises an outwardly and downwardly extending llange 16 of the body 9. Extending around and enclosing iiange 16 is the ange 17 of the metal end 11. Disposed between the outer surface of body flange 16, including the coating 15, and the inner surface of the end flange 17 is a lining material 18. The lining material 18 prevents intimate or sealing contact between the coating 15 and end iiange 17 and provides channels or leak passages through the end seam 13 communicating with the interior of the container. Any metalto-paper contact in the remainder of the seam is of itself non-hermetic and can cause no hermetic seal. In this manner, although the end 11 is securely attached to the body 9, one or more leak paths are provided between the interior of the container and the outside.
When raw biscuit dough is initially packed in a container having this construction, the dough occupies only the bottom portion of the container. Upon standing, the biscuits release carbon dioxide gas and begin to swell. When the pressure inside the container exceeds that of the atmosphere surrounding the container, the pressure producing gas travels up through space occupied by the lining material 18, around the outer surface of the body iiange 16 and vents into the atmosphere. In this manner, the pressure within the container remains substantially atmospheric and produces no resistance to the rising of the biscuit dough. When the dough has risen sufiiciently to ll the entire volume of the container, a portion of the dough squeezes in, fills and seals ot the interior entrance to the space lled by lining material 18. The biscuit dough Ais nowina marketable condition. The rigid construction of the container resists rupturing or bursting thereof upon further increase of internal pressure. However, .tofmaintain'the internal pressure at a minimum, these filled containers are kept under refrigeration.
AReferring to the method of forming the venting container of the instant invention, a fluid lining material 19 is applied to the end ange 17 by any suitable means such as a nozzle 20 (Fig. 2). By virtue of its uidity and the force with which it is ejected from the nozzle 20, the lining material 19 ows upwardly along the vertical portion 21 of the ange 17 and outwardly toward the peripheral curl 22 of the flange 17. Curl 22 must be kept free of the lining 19 so as `to enable curl 22 to have firm engagement with the body flange 16 after double-seaming and thereby securely anchor the top end 11 to body 9. After application, the uid material 19 is vdried by any suitable means Vsuch as air drying `or exposure to heat, such as in an oven to form a solid, friable or brittle lining material 23 V(Fig. 3).
To produce the desired brittleness or friability in the liner 23, the lining composition Vcontains a preponderence, i.e. over 90%, of filler material such as powdered, hydrated, aluminum silicate, known commercially as Buca clay. As a temporary binder for the filler particles and to enable the lining, after drying, to form a continuous solid lm, the composition contains a small percentage of an elastomeric material, such as a styrene-acrylonitrile copolymer (Buna N) or a styrene-butadiene copolymer (GR-S). For ease of application, optional ingredients, such as thickeners and wetting agents, may be added to the composition.
After the container has been packed with a gas producing product such as raw biscuit dough, the end 11 is loosely positioned on the body 9 the peripheral edge of which has been turned outwardly to form the body ange 16. The two members, i.e. end 11 and body 9, are then tightly interengaged or interfolded, such as by double seaming between opposed seaming members, roller 24 and chuck 25 as best shown in Fig. 4. The tight nterengagement of the body and end anges rigidly attaches `the end to the body and provides the strength necessary to resist displacement or blowing ot of the end from the body due to any internal pressure generated in the container.
During the double seaming operation, the pressure eX- erted by the seaming members 24, 25 causes the liner 23 to fracture and become discontinuous at a plurality of places throughout the seam thereby providing the desired leak passages through the seam. Although the exact mechanism by which the discontinuous lining 18 performs its function is not known, tests have proved the instant invention to be effective in providing a venting end seam.
It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will `be apparent that various changes may be made in the form, construction and arrangement of the parts and that changes may be made in the steps of the method described and their order of accomplishment without departing from .the spirit `andscope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.
1. In a container comprising a tubular interiorly coated libre body and a metal end closure attached to the top and bottom end of said body by means of a double seam, theimprovement comprising a lining consisting essentially of an inert pulverulent material enclosed within at least one of said double seams and forming a layer in said seam between said closure and the wall of said body, said layer being in communication with the interior of said container and with the wall of said body whereby gas under pressure within said container is vented through said pulverulent material to outside of said container.
2. The container according to claim 1 wherein said lining is in one double seam only.
3. The container according to claim l wherein said lining is in the top double seam only.
References Cited in the file of this patent UNITED STATES PATENTS 2,005,055 Sprague June 18, 1935 2,164,055 Ellstrom June 27, 1939 2,176,950 Aumont Oct. 24, 1939 2,3 89,534 OBrien Nov. 24, 1945 2,455,737 Coyle Dec. 7, 1948 2,633,095 Magill Mar. 3l, 1953 2,819,006 Magill Jan. 7, 1958 2,855,884 Magill Oct. 14, 1958