US2708050A

US2708050A - Hermetically-sealed container

Info

Publication number: US2708050A
Application number: US294826A
Authority: US
Inventors: Paul R Luertzing; Walter O Luertzing
Original assignee: TRANSPARENT CONTAINERS Inc
Current assignee: TRANSPARENT CONTAINERS Inc
Priority date: 1952-06-21
Filing date: 1952-06-21
Publication date: 1955-05-10
Anticipated expiration: 1972-05-10

Description

y 1955 P. R. LUERTZING E AL HERMETICALLY-SEALED CONTAINER Filed June 21 1952 'llmllillllllllllll W I I IH. I l lllr/lllllllll/llad w 3 a J I I 0 2V w I n 'IIIIII a iy/ 2,798,050 Fatentecl May ll), 1955 messes HERMETIQALLY-SEALED CONTAKNER Paul R. Luertzing and Walter (B. Luertzing, Vineland,

N. 3., assignors to Transparent Containers, Inn, (Zamden, N. J., a corporation of New Jersey Application June 21, 15 52, Serial No. 294,826

Claims. (Cl. 215-40) This invention relates to closures for hermetically sealing containers, such as the glass jars and bottles commonly used in the packing of food products, including vegetables, fruits, mayonnaise, etc. More particularly, the invention is concerned with a novel closure capable of application to a container to cooperate with a pcripheral sealing surface thereon to effect a seal, which remains tight, even though a substantial pressure may be developed within the container, as, for example, during processing of the contents.

Up to the present, many kinds of closures have been devised for hermetically sealing glass containers, and such closures commonly take the form of a cap, usually of sheet metal, which has a top panel intended to overlie the container opening and a skirt telescoping over the end or neck of the container. The seal is then effected by means of .a gasket carried by the cap and held in tight contact with a sealing surface on the container. in some constructions, the sealing surface is formed on the end of the container around the opening, in which event, the seal is referred to as a top seal. In other containers, the sealing surface is generally conical and lies adjacent the end of the container and the closure forms an angle seal. A container having a substantially cylindrical sealing surface is sealed by a side seal.

Closures of the top seal type are subject to the disadvantage that the sealing element lies between the top panel of the cap and the sealing surface on the top of the container, so that, if pressure develops within the container, the top panel of the cap is liable to be bulged outwardly away from the element. between the element and the sealing surface is weakened or destroyed.

In angle seal closures, it is possible to keep the cost of the production down by making the sealing element of a flowable sealing compound, which can be cured by heat-to non-flowing resilient condition. In such closures as ordinarily made heretofore, the compound is introduced into the cap in the angle defined by the top panel and the skirt of the cap and, when the closure is applied to the container, a considerable part of the compound overlies the top of the container to make a top seal. This portion of the compound acts in the same manner as a sealing element in a top seal and is thus ineffective to seal against pressure. Also, bulging under pressure of the top panel of the cap of an angle seal closure is liable to cause a separation of the cap from that part of the element in contact with the sealing surface or a separation of that part of the element from the surface, so that leakage through the seal develops.

Side seal closures provide a more effective and reliable seal than either top or angle seal closures, but, as made up to the present, side seal closures have ordinarily required a pre-formed gasket made of sheet or extruded tube material. Although only a narrow zone of the gasket in such a closure effects the sealing, the peculiarities of the construction are such that the gasket employed must be much wider than the efiective zone thereof. As

As a result, the seal the cost of a pre-formed gasket is an important item in the total cost of the closure, it will be apparent that the use of a gasket wider than its efiective zone is a wasteful practice.

The present invention is directed to the provision of a novel closure of the side seal type, which can be applied to a container having a suitable exterior finish to effect a seal capable of withstanding pressures developed in such containers during the processing of their contents and equalling 30 lbs. per sq. in. or more. The new closure is simple and inexpensive to produce and it can be readily applied by the machines ordinarily employed for the purpose.

The new closure comprises a cap made up of a top panel and 21 depending skirt and it includes a sealing body or element made of a compound, which can be introduced into the cap in fluent condition and then cured to become resilient, the cured compound thereafter being capable, upon being heated to a suitable temperature, of being deformed or molded to a different shape, which the compound will retain when cold. The closure is employed with a container having an exterior finish, including a cylindrical sealing surface extending inward from the open end of the container and a shoulder surface at the inner end of the sealing surface having an external edge of greater diameter than the sealing surface. The cap can be telescoped over the sealing and shoulder surfaces and, when in place, it defines with such surfaces a sealing cavity having an outer throat between the top panel and the end of the container and an inner throat between the skirt and the container finish inward from the shoulder surface. The finish is formed with abutment means inward from the inner throat and the free end section of the skirt is adapted to be engaged behind the abutment means to hold the closure in place.

The closure is applied to the container with the sealing compound cured and heated to moldable condition and the volume of the compound is substantially greater than the volume of the sealing cavity. As the closure is moved into position, the compound is compressed and is molded by contact with the container finish to produce a sealing element, under compression, which completely fills the cavity and extends into and closes both throats. When the closure is in final sealing position with its skirt end section engaged behind the abutment means, .the element is held under pressure in tight contact with the skirt and the sealing and shoulder surfaces of the finish and bulging of the top panel of the cap under internal pressure causes a circumferential zone of the skirt to move inward to apply increased pressure to the element and thus increase the elfectiveness of the seal.

For a better understanding of the invention, reference may be had to the accompanying drawing, in which Fig. l is a fragmentary vertical sectional view of the upper end of a container provided with one form of the new closure;

Fig. la is a fragmentary vertical sectional view of the lower end of a container provided with another form of the new closure;

Fig. 2 is a fragmentary vertical sectional view through the closure of Fig. 1 before its application, the closure being shown on a smaller scale than in Fig. l;

Fig. 3 is a View partly in vertical section and partly in elevation showing the closure of Fig. 2 applied to a container;

Figs. 4 and 4a are views similar to Figs. 1 and la, respectively, but show the container as having a different exterior finish;

Fig. 5 is a view similar to Fig. 2 of a form of the new closure provided with screw threads; and

Fig. 6 is similar to Fig. 2 and shows another form 0 the new closure.

The new closure, as illustrated in the drawing, is intended for application to a container 10 made preferably of glass and having an open end provided with an exterior finish to be described. The container may have a closed bottom end like a jar or bottle, or else it may be open at both ends with both openings closed by the new closure. In the latter event, the container is provided with an exterior finish at the bottom as well as at the top.

The exterior finish at the top of the container comprises a cuwed outer corner surface 10. An outer cylindrical sealing surface 11, extends inward from the curved corner surface 10 at the top 12 of the container wall for a substantial distance. At the inner end of the sealing surface, the finish includes a shoulder surface 13, and an inner cylindrical surface 14 of substantially the same diameter as the external edge of the shoulder surface extends inward from that edge. The finish also includes abutment means 15 inward from the shoulder surface along the inner cylindrical surface, and, in the construction shown in Figs. 1 and 3, the abutment means take the form of a circumferential row of spaced projections 16, which are generally oval in section and lie with their long axes in a plane normal to the axis of the container. In the construction shown in Figs. 1 and 3, the shoulder surface is generally frusto-conical, but this is not essential and the surface may lie substantially in a plane normal to the axis of the container.

The closure comprises a cap 17, which is preferably of sheet metal and includes a circular top panel 18. A skirt having a cylindrical section i9 is connected to the panel along its periphery and the cylindrical section has a length greater than the distance from the plane of the end of the container to the radial plane through the external edge of the shoulder surface. Accordingly, when the closure is in place on the container, the cylindrical section of the skirt overlaps the inner cylindrical surface 14 by a substantial distance. The internal diameter of the skirt 1? is greater than the diameter of the outer edge of the shoulder surface by an amount sufficient only to provide a clearance space or throat. The free end of the skirt is formed by a fastening section 20, which is of greater diameter than the cylindrical section of the skirt and has its edge turned back upon itself to form a curled head 21, which can pass over and engage behind the projections 16 as the closure is telescoped over the end of the container. The cap is preferably stamped from sheet metal, which has been coated with an enamel on the surface, which is to form the interior of the cap. The enamel preferred is one having a vinyl content.

The closure includes a body 22 formed of a sealing compound, which is normally fluent and is curable by heat to a non-flowing resilient condition. After curing, the cured compound is capable, upon being heated, of being molded to a new shape, which the compound will retain on cooling. The uncured compound is flowed into the cap to fill the angle between the top panel and the cylindrical section of the skirt and the compound thus initially forms a body triangular in vertical section and having a long side in contact with the inner surface of the cylindrical section of the skirt and a short side in contact with the inner surface of the panel. The hypotenuse of the original triangular body is indicated by the dotted line 25, Fig. l.

In flowing the compound in place, it is important that the long side of the triangular body of the compound be longer than the distance between the planes through the top end of the container and through the external edge of the shoulder surface of the finish. Also, the short side should have a length not substantially greater than half the length of the long side. The short side may be r as small as two-fifths the length of the long side, but, in all cases, the inner diameter of the body of compound at its end in contact with the top panel of the closure should be less than the diameter of the outer cylindrical sealing surface 11 of the finish.

The compound employed may be that sold by the Dewey and Almy Chemical Company under the tradename Darex 100% S22l. This compound is a pasteresin composition that forms into a tough permanent rubbery mass upon heating at a temperature of, for example, 380 F. for a period of about one minute. The compound, when set, remains sufiiciently elastic for effective sealing of the closure and container and also forms a firm bond to the enamel coating of the closure.

In the application of the closure to seal the container, the body of compound, which has been previously cured to resilient condition, is heated to a temperature of, for example, 250 F. The closure is then telescoped over the container and forced into the position shown in Fig. l with the curled edge 21 of the cap in engagement with the inner side of the abutment means. When the closure is in this position, the cylindrical section of the skirt and the top panel of the closure, together with the outer cylindrical sealing and shoulder surfaces of the exterior finish of the container, define a sealing cavity, which has a smaller volume than the body of cured compound within the cap. The panel is spaced from the open end of the container a distance to provide a narrow clearance space or throat 23 which leads from the upper end of the cavity between the top of the container and the top panel of the closure and a similar narrow clearance space or throat 24 leads from the inner end of the cavity between the inner cylindrical surface 14 and the cylindrical section 19 of the skirt. As the closure is moved inwardly, the curved corner surface 10' exerts an outward radial force on the body of sealing compound. The narrowness of the clearance space or throat 24 prevents any substantial amount of the sealing compound being forced from the cavity at its lower end. This results in the sealing compound being compressed between the cylindrical sealing surface 11 and the inner surface of the skirt 19. When the closure is firmly in position with the curled edge of the skirt behind the abutment means, the sealing element completely fills the cavity and is under substantial compression and in tight contact with the inner surface of the cap and the surfaces of the finish of the container facing the cap, particularly the cylindrical sealing surface 11 and the inner wall of the cylindrical portion 19 of the skirt, where the seal is made. Thin fins also extend into and close the

throats

23 and 24. The sealing compound is molded in this form.

When the closure has been completed by the molding of the cured compound to produce the sealing element, which fills the sealing cavity and the throats as described, the element under compression effects a tight seal for the container. The amount of material employed for the element is so proportioned with relation to the volume of the sealing cavity that thin fins always project from the main body of the sealing element into the throats to close them.

When substantial pressure develops within a container sealed by the new closure applied in the manner described, the pressure may cause the central part of the top panel to bulge outwardly. When this occurs, the cylindrical section of the skirt inward from the top end of the container has a tendency to bend inwardly along a zone and apply greater pressure to the sealing element within the cavity. Separation of the top of the panel from the top of the container may free the panel slightly from the fin within the outer throat 23, but such bulging of the panel has no effect in weakening or impairing the seal provided by the sealing element within the cavity and in the inner throat.

The closure illustrated in Fig. 1 can be readily removed by forcing the curled edge 21 upward over the abutment means and the closure can then he slipped from the container and subsequently reapplied. When the container has an open lower end to be closed by a closure, which is not normally removable, the exterior finish of the container differs slightly from that above described in that it is not necessary to provide an inner cylindrical sealing surface. As before, the finish includes a cylindrical sealing surface 26 leading inward from the end of the container and a shoulder surface 27 at the inner end of the cylindrical surface. The shoulder surface may be the outwardly facing surface on a circumferential rib 28, the inner surface of which serves as the abutment means. The closure includes a cap 29 having a circular panel 30 with a cylindrical skirt 31, which is of a diameter such as to pass by the rib 28 with a slight clearance. The closure includes a body 32 of sealing compound, which initially is triangular in section with a hypotenuse indicated by the dotted line 33. The long side of the body is longer than the distance between the plane through the bottom end of the container and the median plane through rib 28, which is normal to the axis of the container. The short side of the body is not greater than half the length of the long side, and the inner diameter of the body at its end in contact with panel 3! is less than the diameter of the cylindrical sealing surface 26.

In the application of the closure to the bottom of the container, the compound, which has been flowed into the cap in the same manner as described in connection with the top closure and has then been cured, is heated to make it moldable and the cap is then telescoped over the bottom end of the container. When the cap is in position with the free edge of the skirt projecting well beyond the rib 28, an outer throat 34 is formed between panel 30 and the bottom of the container and a similar throat 35 is formed between the skirt on the cap and the outer surface of rib 28. As the closure is forced into position, the body of cured compound is molded to produce the sealing element, which fills the sealing cavity defined by the panel and skirt and by the cylindrical sealing and shoulder surfaces on the container finish. As the sealing element is greater in volume than the sealing cavity, some of the material in the element enters and fills the outer and

inner throats

34, 35. When the closure has been fully moved into place, the free end 36 of the skirt is bent inwardly, as by a rolling operation, to make tight contact with the inwardly facing surface on rib 28. The closure is then held firmly in place and makes a tight seal.

In the construction shown in Figs. 1 and 1a, the shoulder surfaces 13 and 27 are somewhat frusto-conical and such a shape is preferred, since it is easier to form such surfaces in the production of the containers. However, it is not necessary that the shoulder surfaces taper in diameter and these surfaces may lie substantially in plane normal to the axis of the container as shown at 37, 38 in Figs. 4 and 4a. Except for the difference in the shoulder surfaces, the top finish shown in Fig. 4 is similar to that shown in Fig. 1 in all essential respects, and the bot tom finish shown in Fig. 4a is likewise similar to the bottom finish shown in Fig. 1a.

The top closure, illustrated in Figs. 1, 2, and 4, is provided with an inner end section on the skirt of the cap provided with a curled edge, which passes over abutment means in the form of spaced oval projections 16 to hold the closure in place. If desired, the top closure may be of the screw thread type, as shown in Fig. 5. Such a closure is employed with a container, the exterior finish of which is similar to that shown in Fig. 1, in that it includes an outer cylindrical sealing surface, a shoulder surface, and an inner cylindrical sealing surface. The abutment means in the form of projection 16 are then replaced by screw threads engageable with the threads formed in the inner end section 39 of the skirt of the cap. The closure, as before, includes a body 40 of cured sealing compound having the shape and proportions above set forth in relation to the dimensions of the exterior finish on the container and, when the closure is applied with the compound in moldable condition and the closure is threaded into position, the compound is converted into a sealing element, which completely fills a sealing cavity and extends into and closes inner and outer throats similar to

throats

23, 24, described in connection with the closure shown in Fig. 1.

The closure shown in Fig. 6 is similar to those above described and differs therefrom only in the respect that the central area 41 of the top panel of the cap is indented and the inner end section of the skirt is provided with flutes 42, which can be forced inwardly to engage behind abutment means on the exterior finish of the container in the manner of application of an ordinary crown cap. The closure is provided with a body 43 of cured sealing compound, which functions upon application of the closure to produce a sealing element, which fills a sealing cavity and closes inner and outer throats leading therefrom.

The new closure may be employed in vacuum packing operations, which involve the introduction of superheated steam of a temperature of 500-600 F. in the form of a jet into the open end of the container to displace air from above the contents, a vacuum then being created within the container when the steam condenses. When the new closure is used in such operations, the steam jet softens the cured compound, and also moistens and lubricates it so that the compound can be readily molded to produce the sealing element, which fills the sealing cavity and closes the throats leading from opposite ends thereof. When the new closure is employed in dry vacuum packing, in which the space in the upper end of the containers above the contents is evacuated by mechanical means, the closure is heated before application to soften the cured compound and make it moldable. Such heating may be readily effected by means employed with the mechanism for applying the closure.

The containers, to which the closure is applied, have been described as having cylindrical peripheral sealing surfaces, but it is to be understood that exactly cylindrical surfaces cannot be conveniently made on glassware produced by ordinary methods. It is, accordingly, to be understood that, in referring to these surfaces as cylindrical, we mean to include surfaces, which may taper in diameter toward the open end of the container, provided such surfaces make an included angle with an enclosing cylinder, which is considerably steeper than 45. Similarly, in flowing the compound into the cap and then curing it by heat, the body of cured compound may have an hypotenuse side, which is slightly convex or concave. The plane through the internal edge of the shoulder surface on the finish, that is, the edge at which the surface joins the cylindrical sealing surface lying outwardly therefrom, should lie at least as near the plane through the end of the container as the plane through the external edge of the shoulder surface. Preferably, the plane through the internal edge of the shoulder surface lies closer to the plane through the end of the container than the plane through the external edge of the surface, as in the construction shown in Fig. 1. Any increase in the slope of the shoulder surface beyond that shown in Fig. l, is not useful in effecting a seal and results in the use of more of the compound than is necessary for a tight seal.

When the new closure is being applied to a container, the cured sealing compound in the closure is in moldable condition and, as the closure is forced into place, the compound is molded in contact with the finish to form the sealing element filling the sealing cavity and the inner and outer throats. Since the finish forms part of the mold used in producing the sealing element, the element is in full contact with the finish, regardless of variations in the finish, such as out-of-roundness, mold seams, etc., permissible as commercial tolerances in the manufacture of containers. When the body of cured compound has been formed into the sealing element, the compound retains the shape of the element upon cooling and also resumes its resilience. As each sealing element is thus formed during application of the closure, each a container, to which the closure is applied, may be regarded as being provided with an individual seal best suited for sealing that container. As the sealing element is tightly compressed in the sealing cavity and throats after the closure is in place, the new closure makes a tight seal against either pressure or vacuum.

We claim:

1. A container having an open end with a curved outer corner surface, an exterior finish adjacent said open end including a cylindrical sealing surface extending axially inwardly therefrom and a radially outwardly-extending shoulder surface at the inner end of the cylindrical sealing surface, a closure for said open end of the container, said closure comprising a circular panel and a cylindrical skirt connected to the panel and with said cylindrical sealing surface, said panel and said shoulder surface forming a cavity for a scaling body, said sliirt having an internal diameter greater than the diameter of the outer edge of the shoulder surface and a length greater than the distance from a radial plane through the outer edge of the shoulder surface and the plane of the adjacent open end of the container, the inner diameter of the skirt being greater than the diameter of the outer shoulder surface by an amount sufficient only to provide a narrow clearance space or throat, the relative diameters of said cylindrical sealing surface and the outer edge of the shoulder surface being such that the width of said clearance space is less than one-half the width of said cavity, and a mo. ed resilient sealing body filling said cavity, said sealing body, before applying the closure to the container, lying within the stage subtended by the inner surface of the closure panel and said skirt and, at such time, being substantially triangular in vertical section with the length of the side in contact with the panel being greater than the Width of said cavity but substantially less than the length of the side in contact with the skirt, tnc scalirg body being forced into said cavity and molded under pressure to conform with the shape of said cavity when the closure is forced into place on the container.

2. A container" as defined in claim 1 in which the radial dimension of said cavity is less than one-half the longitudinal, dimension.

3. A container as defined in claim 1 in which the sealing body extends at least partly in to said clearance space or throat.

4. A container as defined in claim 1 in which the container finish includes outwardly-protruding fastening means and the closure has a fastening section at the side of the cylindrical skirt remote from the panel engaged with said fastening means and held in place on the open end of me container thereby.

5. A cont? ter as defined in claim 4 in which the outwardly-protruding fastening means is a circumferential rib and one side of said rib forms said shoulder surface.

References Cited in the file of this patent UNITED STATES PATENTS