US20140263372A1

US20140263372A1 - Container with concentric segmented can bottom

Info

Publication number: US20140263372A1
Application number: US13/834,836
Authority: US
Inventors: Richard Brewer; Michael Gurka; Jianwen Hu; Gerald Baker; Alvin Widitora; Jeffery Schlei
Original assignee: Silgan Containers LLC
Current assignee: Silgan Containers LLC
Priority date: 2013-03-15
Filing date: 2013-03-15
Publication date: 2014-09-18
Also published as: WO2014143121A1

Abstract

A container including a sidewall and an end panel is provided. The end panel includes a center panel, an elastic portion, and a frustoconical transition portion. The center panel and the elastic portion are configured to transition between a first configuration and a second configuration.

Description

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of containers. The present invention relates specifically to containers with mechanisms configured to vary the container volume under specific conditions.
Conventional commercial production of food packaged in metal containers may involve filling a metal can with food, hermetically sealing the can, and heating the can with the food inside to sterilize and/or cook the food within the can. During one conventional heating procedure, filled, sealed cans are placed within a heated, pressurized chamber to heat the cans to the desired cooking/sterilization temperature using steam. The pressurized chamber is filled with saturated or super-heated steam which in turn provides the energy to heat the can.

SUMMARY OF THE INVENTION

One embodiment of the invention relates to a metal can body. The metal can body includes a cylindrical, metal sidewall having a circular cross-section which defines a volume. The metal can body includes a circular, metal end panel. The end panel closes one end of the cylindrical sidewall. The end panel includes a circular center panel. The circular center panel has a perimeter defined by a bead. A first plane contacts a surface of the panel. The end panel includes an annular, elastic portion extending from the sidewall to a boundary. The annular, elastic portion has a second plane substantially perpendicular to the sidewall and contacting the elastic portion. The elastic portion includes a plurality of ridges substantially concentric with the sidewall. The end panel includes a frustoconical transition portion. The frustoconical transition portion extends from the boundary to the bead connecting the center panel and the elastic portion such that the first plane is offset from the second plane to support the center panel at a first portion in the interior. The center panel is moveable from the first position to a second position by a force exerted from the interior upon the end panel. The second position is outside of the volume. The center panel is returnable to the first position when the force is reduced.
Another embodiment of the invention relates to a method of filling a can. The method includes providing a can body. The can body has a sidewall extending along a longitudinal axis from a first open end to a second end. The can body includes an end panel sealing the second end. The end panel has a center panel portion in a first configuration extending along a first plane. The end panel has a transition portion extending radially outwardly from the center panel portion. The end panel has a radially outer elastic portion extending between the transition portion and the sidewall along a second plane. The second plane is non-coplanar with the first plane. The method includes filling the can body. The method includes coupling a can end to the sidewall to hermetically seal the can body. The method includes heating the contents of the sealed can body. The increased pressure inside the can body resulting from the heating causes the center panel portion to transition from the first configuration to a second configuration in which the center panel portion extends along a third plan on an opposite side of the second plane than the first plane. The second plane and the third plane are non-coplanar. The method includes cooling the contents of the sealed can body. The method includes applying a force to the center panel portion toward the first plane causing the center panel portion to transition from the second configuration to the first configuration.
Another embodiment of the invention relates to a can body. The can body includes a sidewall extending along a longitudinal axis from a first open end to a second end. The can body includes an end panel closing the second end of the sidewall. The end panel includes an outer annular portion including a plurality of ridges. The end panel includes a frustoconical portion extending radially inwardly from the outer annular portion at a first angle. The end panel includes a center portion extending from the frustoconical portion. The center portion is configured to be displaced between a first configuration in which the center portion is located above the lower axial periphery of the sidewall and a second configuration in which the center portion is located below the lower axial periphery of the sidewall.
Alternative exemplary embodiments relate to other features and combinations of features as may be generally recited in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

This application will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements in which:

FIG. 1 is a top isometric view of an embodiment of a container.

FIG. 2 is a bottom isometric view of an embodiment of a container.

FIG. 3 is a bottom plan view of an embodiment of a container

FIG. 4 is a side view of an embodiment of a container.

FIG. 5 is a cross-sectional view taken along the line 5-5 in FIG. 4.

FIG. 6 is a detail view of the area FIG. 6 in FIG. 5.

FIG. 7 is a perspective view of a container with a closure coupled to the container.

FIG. 8 is a cross-sectional view taken along the line 8-8 in FIG. 7.

FIG. 9 is a cross-sectional view of an embodiment of a container with a portion of the end wall in a second configuration.

FIG. 10 is a perspective view of another embodiment of a container.

FIG. 11 is a cross-sectional view taken along the line 11-11 in FIG. 10.

FIG. 12 is a isometric view of another embodiment of a container.

FIG. 13 is a bottom isometric view of the container of FIG. 12.

FIG. 14 is a cross-sectional view taken along the line 14-14 in FIG. 13.

FIG. 15 is a detail view of the area FIG. 15 in FIG. 14.

FIG. 16 is a perspective view of an embodiment of a shaped container.

FIG. 17 is a can heating system according to an exemplary embodiment.

DETAILED DESCRIPTION

Referring generally to the figures, various embodiments of a container are provided. When some containers are filled with food and sealed, the can may be heated with the food inside to sterilize and/or cook the food. As the temperature inside of the sealed container increases, the pressure inside the sealed container increases. If the pressure outside of the container is too low relative to the interior pressure, stress may be placed on the container which can cause the container and/or the closure closing the container to deform, rupture, fail, and/or otherwise render the container unsuitable for use. Some systems place containers in environments of high external pressure while heating to balance the pressure inside of the container to prevent deformation, rupture, and/or failure of the container, however, doing so may be expensive and time consuming.
An embodiment of a container body is provided including an end panel. The end panel includes a feature configured to increase the volume of the container when the interior pressure of the container increases, thus decreasing the interior pressure, reducing stress placed on the rest of the container body, and eliminating the need to place the container in an environment of high external pressure. Additionally, embodiments of container bodies with end panels described herein may allow for use of thinner materials in making containers, as the increase in volume when interior pressure in the containers increases will subject the container materials to reduced stress. The feature is also configured to be returned to, e.g., be able to recover, its initial configuration, e.g., first state of equilibrium, decreasing the volume of the container body back to its initial volume upon cooling of the contents of the container body, returning the interior of the container body to its initial pressure, e.g., regaining the initial pressure inside the container upon sealing. Additionally, the feature is configured to transition between the initial configuration and the second configuration, e.g., second state of equilibrium, without deforming, e.g., irreversibly deforming, wrinkling, large-strain deformation, permanently deforming, etc., the end panel or the container body.
Referring to FIG. 1, a container body, shown as a can body 20, is illustrated according to an exemplary embodiment. The can body 20 includes a sidewall 22 extending along a longitudinal axis from a first open end 24 to a second end closed by an end panel 26. In one embodiment, the sidewall 22 and the end panel 26 are integrally formed.
In one embodiment, the sidewall 22 is a beaded sidewall. In another embodiment, the sidewall 22 is a straight, unbeaded sidewall. In another embodiment, sidewalls discussed herein may be shaped such that cross-sections taken perpendicular to the longitudinal axis of the container are generally circular. However, with reference to FIG. 16, in other embodiments the sidewall of can bodies, such as the can body illustrated therein, may be shaped in a variety of ways (e.g., having other non-polygonal cross-sections, as a rectangular prism, a polygonal prism, any number of irregular shapes, etc.) as may be desirable for different applications.
With reference to FIGS. 2 and 3, the end panel 26 includes a radially outer annular elastic portion 28 extending radially inwardly from the sidewall 22 to a frustoconical angular transition portion 30. The transition portion 30 extends upwardly and radially inwardly from the elastic portion 28 to a circular center panel 32.
With reference to FIGS. 4 and 5, the can body 20 has a height H1. The end panel 26 has a diameter D1. In one embodiment, the height H1 is approximately 4.438 inches. In one embodiment, the diameter D1 is approximately 2.88 inches. In the configuration illustrated in FIG. 5, the center panel 32 extends generally along a first plane P1. The elastic portion 28 extends generally along a second plane P2. The first plane P1 and the second plane P2 are generally parallel and non-coplanar. The center panel 32 is a height H2 above the elastic portion 28, e.g., the plane P1 is a distance H2 above the plane P2. In one embodiment, the height H2 is approximately 0.12 inches. In one embodiment, the height H2 is between approximately 1% and approximately 5% of the height H1 of the can body 20. In another embodiment, the height H2 is between approximately 2% and approximately 3% of the height H1 of the can body 20. In another embodiment, the height H1 is approximately 2.7% of the height H1 of the can body 20.
With further reference to FIG. 5, the transition portion 30 has an outer diameter D2. In one embodiment, the diameter D2 is approximately 1.644 inches. In one embodiment, the diameter D2 of the transition portion 30 is between approximately 40% and approximately 70% of the diameter D1 of the end panel 26. In another embodiment, the diameter D2 of the transition portion 30 is between approximately 55% and approximately 60% of the diameter D1 of the end panel 26. In another embodiment, the diameter D2 of the transition portion 30 is approximately 57% of the diameter D1 of the end panel 26.
As is illustrated in FIG. 5, the perimeter of the center panel 32 is generally defined by a bead 50, e.g., raised portion, ridge, strengthening feature, etc. The center panel 32 has a diameter D3. In one embodiment, the diameter D3 is approximately 0.75 inches. In one embodiment, the diameter D3 of the center panel 32 is between approximately 10% and approximately 40% of the diameter D1 of the end panel 26. In another embodiment, the diameter D3 of the center panel 32 is between approximately 20% and approximately 30% of the diameter of the end panel 26. In another embodiment, the diameter D3 of the center panel 32 is approximately 26% of the diameter of the end panel 26.
In one embodiment, the diameter D3 is between approximately 30% and approximately 60% of the outer diameter D2 of the transition portion 30. In another embodiment, the diameter D3 is between approximately 40% and approximately 50% of the outer diameter D2 of the transition portion 30. In another embodiment, the diameter D3 is approximately 46% of the outer diameter D2 of the transition portion 30.
With further reference to FIG. 5, the transition portion 30 extends at an angle θ1 relative to the plane P2. In one embodiment, the angle θ1 is between approximately 15° and approximately 25°. In another embodiment, the angle θ1 is between approximately 17° and approximately 21°. In another embodiment, the angle θ1 is approximately 19°.
In one embodiment, the elastic portion 28 includes a plurality of ridges 34, 36, 38, 40, 42, 44, 46, and 48, e.g., beads, strengthening features, elasticity-enhancing features, etc. In the illustrated embodiment, the elastic portion 28 includes eight ridges 34, 36, 38, 40, 42, 44, 46, and 48. The ridges 34, 36, 38, 40, 42, 44, 46, and 48 are generally concentric with the sidewall 22.
In one embodiment, the bead 50 extends a height H3 upwardly from the plane P1. In one embodiment, the height H3 is between approximately 0.01 inches and approximately 0.05 inches. In another embodiment, the height H3 is between approximately 0.02 inches and approximately 0.03 inches. In another embodiment, the height H3 is approximately 0.027 inches.
With reference to FIG. 6, in one embodiment, the elastic portion 28 includes eight ridges 34, 36, 38, 40, 42, 44, 46, and 48. The first, radially innermost ridge 34 is located a distance d1 from the sidewall 22. In one embodiment, the distance d1 is between approximately 0.5 inches and approximately 0.6 inches. In another embodiment, the distance d1 is approximately 0.57 inches. In one embodiment, the distance d1 is between approximately 15% and 25% of the diameter D1 (see FIG. 5) of the end panel 26. In another embodiment, the distance d1 is approximately 20% of the diameter D1 (see FIG. 5) of the end panel 26.
The second ridge 36 is located a distance d2 from the sidewall 22. In one embodiment, the distance d2 is between approximately 0.45 inches and approximately 0.55 inches. In another embodiment, the distance d2 is approximately 0.5 inches. In one embodiment, the distance d2 is between approximately 15% and approximately 20% of the diameter D1 (see FIG. 5) of the end panel 26. In another embodiment, the distance d2 is approximately 17% of the diameter D1 (see FIG. 5) of the end panel 26.
The third ridge 38 is located a distance d3 from the sidewall 22. In one embodiment, the distance d3 is between approximately 0.4 inches and approximately 0.45 inches. In another embodiment, the distance d3 is approximately 0.434 inches. In one embodiment, the distance d3 is between approximately 12.5% and approximately 17.5% of the diameter D1 (see FIG. 5) of the end panel 26. In another embodiment, the distance d3 is approximately 15% of the diameter D1 (see FIG. 5) of the end panel 26.
The fourth ridge 40 is located a distance d4 from the sidewall 22. In one embodiment, the distance d4 is between approximately 0.325 inches and approximately 0.4 inches. In another embodiment, the distance d4 is approximately 0.36 inches. In one embodiment, the distance d4 is between approximately 10% and approximately 15% of the diameter D1 (see FIG. 5) of the end panel 26. In another embodiment, the distance d4 is approximately 12.5% of the diameter D1 (see FIG. 5) of the end panel 26.
The fifth ridge 42 is located a distance d5 from the sidewall 22. In one embodiment, the distance d5 is between approximately 0.275 inches and approximately 0.325 inches. In another embodiment, the distance d5 is approximately 0.3 inches. In one embodiment, the distance d5 is between approximately 7.5% and approximately 12.5% of the diameter D1 (see FIG. 5) of the end panel 26. In another embodiment, the distance d5 is approximately 10% of the diameter D1 (see FIG. 5) of the end panel 26.
The sixth ridge 44 is located a distance d6 from the sidewall 22. In one embodiment, the distance d6 is between approximately 0.2 inches and approximately 0.25 inches. In another embodiment, the distance d6 is approximately 0.236 inches. In one embodiment, the distance d6 is between approximately 5% and approximately 10% of the diameter D1 (see FIG. 5) of the end panel 26. In another embodiment, the distance d6 is approximately 8% of the diameter D1 (see FIG. 5) of the end panel 26.
The seventh ridge 46 is located a distance d7 from the sidewall 22. In one embodiment, the distance d7 is between approximately 0.1 inches and approximately 0.2 inches. In another embodiment, the distance d7 is approximately 0.15 inches. In one embodiment, the distance d7 is between approximately 2.5% and approximately 7.5% of the diameter D1 (see FIG. 5) of the end panel 26. In another embodiment, the distance d7 is approximately 5% of the diameter D1 (see FIG. 5) of the end panel 26.
The eighth ridge 48 is located a distance d8 from the sidewall 22. In one embodiment, the distance d8 is between approximately 0.25 inches and approximately 0.75 inches. In another embodiment, the distance d8 is approximately 0.68 inches. In one embodiment, the distance d8 is between approximately 1% and approximately 5% of the diameter D1 (see FIG. 5) of the end panel 26. In another embodiment, the distance d8 is approximately 2.4% of the diameter D1 (see FIG. 5) of the end panel 26.
In other embodiments, the elastic portion 28 may include other suitable numbers of ridges.
With further reference to FIG. 6, the ridges 34, 36, 38, 40, 42, 44, 46, and 48 have a height H4. In one embodiment, the height H4 is between approximately 0.01 inches and approximately 0.05 inches. In another embodiment, the height H4 is approximately 0.02 inches. In the illustrated embodiment, the ridges 34, 36, 38, 40, 42, 44, 46, and 48 each have generally the same height. In other embodiments, the heights of the ridges may be nonuniform.
With reference to FIGS. 7 and 8, the can body 20 is filled through the open end 24 and the open end 24 is sealed, e.g., hermetically sealed, with a closure, in the illustrated embodiment, a can end 52. The can end 52 is coupled to the sidewall 22 by a double seam 54.
When the filled and sealed can body 20 is heated, e.g., to sterilize and/or cook the contents of the can body, 20, because the can body 20 is sealed, e.g., hermetically sealed, by the can end 52, interior pressure within the can body 20 increases, which exerts outwardly directed forces on the sidewall 22, the end panel 26, and the can end 52.
In one embodiment, with the filled and sealed can body 20 under external ambient pressure, e.g., no overpressure applied, etc., the end panel 26, including the elastic portion 28, the transition portion 30, and the center panel 32, is configured such that the transition portion 30 and the center panel 32 will transition (e.g., snap-through, etc.) from the first configuration, e.g., first state of equilibrium, etc., illustrated in FIG. 8 to a second configuration, e.g., second state of equilibrium, etc., illustrated in FIG. 9.
As is illustrated in FIG. 9, in the second configuration, the transition portion 30 extends at an angle θ2 relative to the plane P2. In one embodiment, the angle θ1 is between approximately 15° and approximately 25°. In another embodiment, the angle θ1 is between approximately 17° and approximately 21°. In another embodiment, the angle θ1 is approximately 19°.
In the second configuration illustrated in FIG. 9, the center panel 32 extends along a third plane P3. In one embodiment, the third plane P3 is generally parallel to the second plane P2 and the first plane P1. The third plane P3 is non-coplanar with the second plane P2.
In one embodiment, the volume of the can body 20 in the second configuration is between approximately 0.1% and approximately 7% greater than the volume of the can body 20 in the first configuration. In another embodiment, the volume of the can body 20 in the second configuration is between approximately 0.2% and approximately 3% greater than the volume of the can body 20 in the first configuration. In another embodiment, the volume of the can body 20 in the second configuration is approximately 0.5% greater than the volume of the can body 20 in the first configuration. In another embodiment, the volume of the can body 20 in the second configuration is between approximately 4% and approximately 5% greater than the volume of the can body 20 in the first configuration. In one embodiment, the interior volume of the can body 20 is increased by 1 cubic inch when the center panel 32 and the transition portion 30 are in the second configuration (see FIG. 9) relative to when the center panel 32 and the transition portion 30 are in the first configuration (see FIG. 8).
In one embodiment, during heating, the contents of the can body 22 are heated to approximately 260° F. In one embodiment, the transition portion 30 and the center panel 32 will transition from the first configuration (FIG. 8) to the second configuration (FIG. 9) when the interior pressure inside of the can body 22 is between approximately 20 psig (pound-force per square inch gauge) and approximately 60 psig. In another embodiment, the transition portion 30 and the center panel 32 will transition from the first configuration (FIG. 8) to the second configuration (FIG. 9) when the interior pressure inside of the can body 22 is between approximately 35 psig and approximately 45 psig. In another embodiment, the transition portion 30 and the center panel 32 will transition from the first configuration (FIG. 8) to the second configuration (FIG. 9) when the interior pressure inside of the can body 22 is approximately 40 psig.
Once the heating process is completed, the sealed can body 22 is cooled, e.g., air cooled, cooled in water bath, etc. Similar to during heating, embodiments of the can body 22 with the end panel 26 may eliminate the need to cool (e.g., the initial stages of cooling, etc.) the sealed can body 22 in a pressurized environment, as the net outward force acting on the body and/or end walls of cans after the transition portion 30 and center panel 32 have transitioned to the second configuration is less than the burst strength (i.e., the force at which either the body or end walls of cans will fail, crack, rupture, permanently deform, etc.) of the can body 22 and can end 52.
The end panel 26 including the transition portion 30 and the center panel 32 are configured to remain in the second configuration (FIG. 9) unless the transition portion 30 and the center panel 32 are subjected to a force or pressure, e.g., the transition portion 30 and the center panel 32 are configured to remain in the second configuration (FIG. 9) and not to return to the first configuration (FIG. 8) under ambient conditions unless a force or pressure is applied thereto, as described below.
After the contents of the sealed can body 20 have been sufficiently cooled, the sealed can body 20 has a lower interior temperature and pressure inside the sealed can body 20, e.g., vacuum inside the sealed can body 20, lower pressure inside the sealed can body 20 than when the can body 20 was sealed, etc.
In one embodiment, the end panel 26 is configured such that the center panel 32 and the transition portion 30 are configured to be maintained in the second configuration (FIG. 9), under normal ambient conditions, e.g., between approximately 40° F. and 100° F., between approximately 0.75 atmospheres of pressure and approximately 2 atmospheres of pressure, no increased external force being applied upwardly and/or inwardly to the end panel 26, etc.
A force may be applied to the center panel 32 and/or the transition portion 30 in an upward, e.g., inward, direction, e.g., toward the can end 52, toward plane P1, etc., to cause the transition portion 30 and the center panel 32 to transition from the second configuration (FIG. 9) back to the first configuration (FIG. 8). In one embodiment, this will decrease the volume of the interior of the sealed can body 20 and recover the initial pressure inside the sealed can body 20, e.g., eliminate and/or reduce vacuum, increase pressure to initial pressure in sealed can body 20 immediately after sealing, gain positive pressure inside the sealed can body 20, etc.
As with the transition from the first configuration to the second configuration, the elastic portion 28, the transition portion 30, and the center panel 32 are configured to avoid permanent deformation, wrinkling, etc., e.g., have elastic properties, be configured such that the elastic portion 28, transition portion 30, and center panel 32, each are generally the same structurally and in appearance, before and after the transition portion 30 and the center panel 32 transition from the first configuration (FIG. 8) to the second configuration (FIG. 9) and back to the first configuration (FIG. 8).
When the center panel 32 and the transition portion 30 transition from the first configuration (FIG. 8) to the second configuration (FIG. 9) or from the second configuration (FIG. 9) to the first configuration (FIG. 8), the elastic portion 28 is temporarily deformed, e.g., flexes, etc., to allow the transition, but is configured to return to its original shape and structure, e.g., not wrinkle, not irreversibly deform, elastically deform, etc. The elastic portion 28 and the ridges 34, 36, 38, 40, 42, 44, 46, and 48 are configured to provide the elastic portion 28 with elastic properties, e.g., the ability to resume normal shape spontaneously after distortion, the elastic portion 28 having generally the same shape, appearance, and configuration after the center panel 32 and the transition portion 30 have transitioned to the second configuration (FIG. 9) as when the center panel 32 and the transition portion 30 are in the first configuration (FIG. 8), e.g., the elastic portion 28 is not wrinkled, permanently deformed, etc., by the transition of the center panel and transition portion between the first configuration (FIG. 8) and the second configuration (FIG. 9).
Additionally, with reference to FIGS. 8 and 9, the center panel 32 and the bead 50 are configured to allow the center panel 32 to transition elastically and to provide the center panel 32 with elastic properties, e.g., the ability to recover normal shape spontaneously after distortion, the center panel 32 having generally the same shape and configuration after the center panel 32 and the transition portion 30 have transitioned to the second configuration (FIG. 9) as when the center panel 32 and the transition portion 30 are in the first configuration (FIG. 8), e.g., the center panel 32 is not wrinkled, permanently and/or irreversibly deformed, etc., by the transition of the center panel and transition portion between the first configuration (FIG. 8) and the second configuration (FIG. 9).
Additionally, with reference to FIGS. 8 and 9, the transition portion 30 is configured with elastic properties, e.g., the transition portion 30 is not wrinkled, permanently and/or irreversibly deformed, etc., by the transition of the transition portion 30 and the center panel 32 from the first configuration (FIG. 8) to the second configuration (FIG. 9) or by the transition back from the second (FIG. 9) configuration to the first configuration (FIG. 8).
In one embodiment, the force to transition the transition portion 30 and the center panel 32 from the second configuration (FIG. 9) to the first configuration (FIG. 8) may be applied by an actuator, such as a mechanical actuator, hydraulic actuator, electric actuator, etc., configured to apply a force, e.g., mechanical force, pressure, etc., to the center panel 32 and/or the transition portion 30.
Embodiments of can bodies 20 may eliminate the need to heat cans in pressurized environments, e.g., eliminate the need for additional overpressure, when steam heated other than pressure from saturated steam, when heated by other methods, e.g., induction, other than ambient pressure, the pressure of the contents within the can at the maximum temperature does not rupture, break, fail, or permanently deform the body of the can within the heating chamber at atmospheric pressure, etc. Additionally, embodiments of can bodies 20 may eliminate the need to physically constrain cans from expanding due to heating, e.g., eliminate the need for physical support structures that may engage the can body (e.g., the end walls of the can to resist deformation).
Various methods to heat the contents of sealed cans are not dependent on an elevated pressure within a heating chamber, e.g., induction heating, etc. Embodiments of can bodies 20 with end panels 26 allow for heating of contents of the can bodies 20 without locating the can bodies 20 in a high pressure environment and without any damage, failure, permanent deformation, etc., to the can bodies 20 from the increased internal pressure due to the heated contents of the can bodies 20.
Additionally, embodiments of can bodies 20 may eliminate the need to provide pressurized environments for cooling of cans (e.g., initial stages of cooling) eliminating the need for overpressure.
Additionally, in one embodiment, the configuration of the end panel 26 may allow a can body 20, the end panel 26, and the can end 52 to be formed from a thin material while still being able to withstand, e.g., not permanently deform, burst, etc., the pressure in the interior of the sealed can body 20 when the contents of the sealed can body 20 are heated. The can body 20 may be formed from a metal such as, e.g., aluminum, steel, other alloys, etc. With reference to FIG. 6, the end panel 26 has a thickness T1. In one embodiment, the thickness T1 is between approximately 0.002 inches and approximately 0.01 inches. In another embodiment, the thickness T1 is between approximately 0.005 inches and 0.009 inches. In another embodiment, the thickness T1 is approximately 0.00715 inches.
With further reference to FIG. 6, the sidewall 22 has a thickness T2. In one embodiment, the thickness T2 is between approximately 0.001 inches and approximately 0.005 inches. In another embodiment, the thickness T2 is approximately 0.004 inches. In another embodiment, the thickness T2 is approximately 0.003 inches. In another embodiment, the thickness T2 is approximately 0.002 inches.
In one embodiment, the gauge of the material used to form the can end 52 may be reduced. In one embodiment, the gauge of steel used to form the can end 52 may be reduced from approximately 73 lbs. if an end panel not configured to transition to a second configuration is used to approximately 70 lbs. if the end panel 26 is used.
Having a sidewall 22 and an end panel 26 that may be formed from thinner material (e.g., less material) may provide for cost savings relative to a can body formed from thicker material.
In one embodiment, the can body 20 with the end panel 26 may be formed from metal that has been thinned prior to forming the features of the end panel 26. Embodiments of can bodies 20, e.g., can bodies with thin end panels and thin sidewalls, described herein may be formed using the apparatuses and methods described in U.S. patent application Ser. No. ______ entitled Container With Expanded Bottom and Method, filed on Mar. 14, 2013, which is incorporated herein by reference in its entirety. In another embodiment, the can body 20 may be formed from interstitial-free steel.
In one embodiment, end panel 26 is configured such that the transition portion 30 and the center panel 21 are configured to remain in the first configuration (FIG. 8) after transitioning from the second configuration (FIG. 9) back to the first configuration (FIG. 8) upon cooling of the contents of the sealed can body 20 under normal, ambient conditions, e.g., between approximately 32° F. and 100° F., between approximately 0.5 atmosphere and approximately 2 atmospheres, etc.
With reference to FIGS. 10 and 11, another embodiment of a can body 120 is provided. The can body 120 has many similarities to the can body 20 described above, therefore, differences between the can body 120 and the can body 20 are the focus of the description below.
The can body 120 includes a sidewall 122 extending from a first open end 124 to a second end. The second end is sealed, e.g., hermetically sealed, by a can end 126 coupled to the sidewall 122. In one embodiment, the can end 126 is coupled to the sidewall 122 by a double seam. As is illustrated in FIGS. 10 and 11, the end panel 126 is not integrally formed with the sidewall 122.
In one embodiment, a second end panel, similar to the end panel 126 may be coupled to the first end 124 of the sidewall 122, e.g., by a double seam, etc., to seal, e.g., hermetically seal the first end 124 of the sidewall 122. In this configuration, the center portions and transition portions of both the end panel 126 and the second end panel are configured to transition to a second configuration to increase the volume of the interior of the sealed can body 120. In one embodiment, this configuration would provide additional, e.g., twice as much, increase in volume in the interior of the sealed can body 120 when the center portions and the transition portions of both end panels are in the second configuration.
With reference to FIGS. 12-15, another embodiment of a can body 220 is illustrated. The can body 220 has many similarities to the can bodies described above, therefore, differences between the can body 220 and the can bodies above are the focus of the description below.
The can body 220 includes an elastic portion 228 extending generally from the sidewall 220 to the angular transition portion 230. The elastic portion 228 includes six ridges, e.g., beads, strengthening features, elasticity-enhancing features, etc. In the illustrated embodiment, the ridges 234, 236, 238, 240, 242, 244, 246, and 248 are generally concentric with the sidewall 222.
The first, radially inwardmost ridge 234 is located a distance d9 from the sidewall 222. In one embodiment, the distance d9 is between approximately 0.55 inches and 0.6 inches. In another embodiment, the distance d9 is approximately 0.57 inches. In one embodiment, the distance d9 is between approximately 15% and approximately 25% of the diameter D1 (see FIG. 14) of the end panel 226. In another embodiment, the distance d9 is approximately 20% of the diameter D1 (see FIG. 14) of the end panel 226.
The second ridge 236, located radially outwardly from the first ridge 234, is located a distance d10 from the sidewall 222. In one embodiment, the distance d10 is between approximately 0.45 inches and approximately 0.55 inches. In another embodiment, the distance d10 is approximately 0.5 inches. In one embodiment, the distance d10 is between approximately 15% and approximately 20% of the diameter D1 (see FIG. 14) of the end panel 226. In another embodiment, the distance d10 is approximately 17% of the diameter D1 (see FIG. 14) of the end panel 226.
The third ridge 238, located radially outwardly from the second ridge 236, is located a distance d11 from the sidewall 222. In one embodiment, the distance d11 is between approximately 0.4 inches and approximately 0.45 inches. In another embodiment, the distance d11 is approximately 0.434 inches. In one embodiment, the distance d11 is between approximately 12.5% and approximately 17.5% of the diameter D1 (see FIG. 14) of the end panel 222. In another embodiment, the distance d11 is approximately 15% of the diameter D1 (see FIG. 14) of the end panel 222.
The fourth ridge 240, located radially outwardly from the third ridge 238, is located a distance d12 from the sidewall 222. In one embodiment, the distance d12 is between approximately 0.35 inches and approximately 0.4 inches from the sidewall 222. In another embodiment, the distance d12 is approximately 0.36 inches. In one embodiment, the distance d12 is between approximately 10% and approximately 15% of the diameter D1 (see FIG. 14) of the end panel 222. In another embodiment, the distance d12 is approximately 12.5% of the diameter D1 (see FIG. 14) of the end panel 222.
The fifth ridge 242, located radially outwardly from the fourth ridge 240, is located a distance d13 from the sidewall 222. In one embodiment, the distance d13 is between approximately 0.25 inches and approximately 0.35 inches. In another embodiment, the distance d13 is approximately 0.3 inches. In one embodiment, the distance d13 is between approximately 7.5% and 12.5%. of the diameter D1 (see FIG. 14) of the end panel 222. In another embodiment, the distance d13 is approximately 10% of the diameter D1 (see FIG. 14) of the end panel 222.
The sixth ridge 244, located radially outwardly from the fifth ridge 242, is located a distance d14 from the sidewall 222. In one embodiment, the distance d14 is between approximately 0.2 inches and 0.25 inches. In another embodiment the distance d14 is approximately 0.236 inches. In one embodiment, the distance d14 is between approximately 6% and approximately 10% of the diameter D1 (see FIG. 14) of the end panel 222. In another embodiment, the distance d14 is approximately 8% of the diameter D1 (see FIG. 14) of the end panel 222.
In one embodiment, the diameter D1 of the end panel 226 is generally the same as the diameter D1 of the end panel 26.
In one embodiment, embodiments of the elastic portions 28, 228 may be formed from a different material than the rest of the end panels 26, 226, e.g., formed from non-metal material. In one embodiment, the elastic portions 28, 228 may be formed from plastic. In another embodiment, the elastic portions 28, 228 may be formed from rubber.
In one embodiment, container bodies including end panels such as, e.g., end panels 26, 126, 226 may be filled, sealed, and heated by induction heating systems such as, e.g., induction heating systems described in U.S. patent application Ser. No. 13/832,573, entitled “Induction Heating System for Food Containers and Method,” filed on Mar. 15, 2013, which is incorporated herein in its entirety by reference. However, container bodies including panels 26, 126, 226 are configured such that the container bodies may be heated by, e.g., induction heating, without locating the container bodies in a pressurized environment, e.g., overpressure. Additionally, the container bodies including end panels 26, 126, 226 are configured such that the container bodies may be heated, e.g., by induction heating, without the use of apparatuses to physically support the containers to resist outward deformation as the container body is heated.
Referring to FIG. 17, a can heating system 310 is shown according to an exemplary embodiment. System 310 includes a container mover or can mover, shown as conveyor 312, that is configured to move cans 314 through the various portions of system 310. In the embodiment shown in FIG. 17, a plurality of cans 314 are shown located next to each other along conveyor 312, such that each can 314 moves sequentially through the various sections of system 310. The cans 314 include end panels such as the end panels 26, 126, 226, described above, configured to vary the volume of the interior of the cans 314 under various conditions. In the exemplary embodiment shown, system 310 includes a preheating section, shown as preheating chamber 316, a first heating section, shown as heating chamber 318, a second heating section, shown as heating chamber 320, and a cooling section, shown as cooling chamber 322. In the illustrated embodiment, neither of heating chambers 18 and 20 are pressurized. An airlock, such as first airlock 324, need not be utilized between preheating chamber 316 and heating chamber 318. Additionally, a second airlock 326 is illustrated but need not be utilized as heating chambers 18 and 20 are not pressurized.
Chambers 318 and 320 are unpressurized chambers that are configured to heat the cans within the chamber to a maximum temperature such that the pressure of the contents within the can at the maximum temperature does not rupture, break or permanently deform the body of the can within the heating chamber at atmospheric pressure (i.e., without a pressurized chamber), with the end panels transitioning from a first configuration (e.g., FIG. 8) to a second configuration (e.g., FIG. 9). Physical support structures to engage the can body need not be provided. The heating chambers are unpressurized induction heating chambers and the cans (e.g., cans 314) heated within the induction coils are configured with an end panel such as, e.g., end panels 26, 126, 226, that transitions to a second configuration (e.g., FIG. 9) under the internal heating pressure and remains in the second configuration until a punch or other machine pushes the end wall back in following heating.
Preheating chamber 316 is an initial heating area configured to raise the temperature of cans 314 above ambient temperature prior to the cans entering the primary heating chambers (e.g., heating chambers 318 and 320). In the embodiment shown, preheating chamber 316 heats cans 314 using a non-induction heat sources (e.g., heat supplied from recycling heat from other portions of the system). The preheating provided by preheating chamber 316 lessens the amount of heating that must be applied to cans 314 within heating sections 318 and 320. To raise cans 314 above ambient temperature preheating chamber 316 is maintained at a temperature above ambient temperature, but is generally lower than the cooking temperature or lower than the sterilization temperature of cans 314. In one embodiment, the temperature within preheating chamber 316 is above ambient temperature in the location of system 310. In various embodiments, the temperature within preheating chamber 316 is between 70 and 212 degrees Fahrenheit, specifically is between 90 and 170 degrees Fahrenheit, and more specifically is between 110 and 150 degrees Fahrenheit.
As shown in FIG. 17, preheating chamber 316 includes one or more passive heat sources. In some embodiments, the passive heat sources transfer excess heat from one section of system 310 into preheating chamber 316 providing energy to preheat cans 314 within chamber 316. In one embodiment, system 310 includes a conduit 328 which transfers heat (e.g., heat air, heated water, other heated fluid, etc.) from cooling chamber 322 to preheating chamber 316. Thus, in this embodiment, heat from cooling cans 314 within cooling chamber 322 is captured and transferred from cooling chamber 322 into preheating chamber 316 via conduit 328. In addition, system 310 may include a helical coil cooling system 330, and excess heat generated by helical coil cooling system 330 is transferred to preheating chamber 316 via a second conduit 332. Preheating cans 314 within preheating chamber 316 utilizing excess heat from other portions of system 310 may reduce the amount of energy needed to heat within heating chambers 318 and 320.
In another embodiment, preheating chamber 316 may include an induction heating coil to preheat cans 314 prior to entering the primary heating chambers.
Generally, heating chamber 318 includes a first induction heating coil, shown as helical induction coil 334. Helical coil 334 is shown surrounding (e.g., wrapping around) conveyor 312 such that conveyor 312 passes through a central lumen 336 or passage defined by the inner surface of helical coil 334. In the embodiment shown, central lumen 336 is a substantially cylindrical space bounded by coil 334. Cans 314 move through the lumen of helical coil 334 on conveyor 312 such that cans 314 move sequentially through heating chamber 318.
Coil 334 is a coil formed from an electrically conductive material (e.g., copper, hollow copper tube, etc.) such that application of an alternating current to coil 334 generates an alternating magnetic field within lumen 336 of coil 334. In the embodiment shown, cans 314 are made from a electrically conductive material, specifically a metal material, such that the magnetic field generated within coil 334 induces current (e.g., eddy currents) within the body and/or end walls (e.g., end panels of a three piece can, an integral end wall of a two piece can, etc.) of cans 314. In one embodiment, cans 314 are made from an iron-based material, and in a specific embodiment, cans 314 are made from a steel material. In another embodiment, cans 314 may be formed from a non-electrically conductive material (e.g., a plastic material) with embedded electrically conductive structures and/or suseptors (i.e., embedded material or elements which can have current induced by coil 334 and which generates heat via resistive heating). The induced current causes resistive heating of the body and end walls of cans 314, which in turn heats the contents of can 314.
Because cans 314 are hermetically sealed cans, as the contents of can 314 heat up, the pressure within each can 314 increases which exerts outwardly directed forces on the body and end walls of cans 314. In one embodiment, heating chamber 318 is configured to heat the contents of cans 314 to between 230 degrees and 260 degrees Fahrenheit, and is configured to be pressurized to between 10 psi and 25 psi. In another embodiment, heating chamber 318 is configured to heat the contents of cans 314 to between 217 degrees and 310 degrees Fahrenheit, and is configured to be pressurized to between 15 psi and 90 psi. In one embodiment, heating chamber 318 is part of system for heating high acid foods and is configured to heat the contents of cans 314 to between 170 degrees and 195 degrees Fahrenheit.
In the embodiment shown in FIG. 17, system 310 includes a second heating chamber, shown as heating chamber 320. Heating chamber 320 includes a second induction heating coil, shown as helical induction coil 338, defining a lumen 340. Heating chamber 320 and coil 338 function substantially the same as heating chamber 318 and coil 334 discussed above, such that cans 314 are heated by the resistive heating of the can body and/or end walls of cans 314 within the alternating magnetic field generated by coil 338.
In one embodiment, heating chamber 320 is configured to heat cans 314 to a higher temperature than heating chamber 318 to finish the cooking and/or sterilization of cans 14. Thus, in such embodiments, heating chamber 320 is configured to continue the heating started by heating chamber 318. In such embodiments, heating chamber 320 is configured to finish heating the contents of cans 314 to between 230 degrees and 260 degrees Fahrenheit, and is configured to be pressurized to between 10 psi and 25 psi. In another embodiment, heating chamber 320 is configured to finish heating the contents of cans 314 to between 217 degrees and 310 degrees Fahrenheit, and is configured to be pressurized to between 15 psi and 90 psi. In one embodiment, heating chamber 320 is part of system for heating high acid foods and is configured to heat the contents of cans 314 to between 170 degrees and 195 degrees Fahrenheit. Higher heating may be accomplished within chamber 20 by varying the heating properties of coil 338. For example, in one embodiment, the coil density of coil 338 (i.e., the number of rotations of coil per unit length of coil) is greater than the coil density of coil 334. In another embodiment, the frequency of the current within coil 338 (and consequently the frequency of the alternating magnetic field) and/or the amount of current within coil 338 is greater than the frequency and/or current within coil 334.
In various embodiments, sealed cans 314 may be subjected to induction heating within the induction coil of chamber 318 and/or 320 for between 10 seconds and 4 minutes, specifically between 15 seconds and 3 minutes, and more specifically between 20 seconds and 2 minutes. Then, following heating for the selected time, the can may be removed from the induction field to allow the heat imparted to the can while within the induction coil to transfer throughout the contents of the can to finish heating of the contents.
As shown in FIG. 17, conveyor 312 carries cans 314 through lumens 336 and 340 of induction coils 334 and 338, respectively. In this configuration, the portions of conveyor 312 located within coils 334 and 338 are formed from a non-electrically conductive material. Specifically, conveyor 312 may be formed from high strength, temperature tolerant polymer materials.
Cooling chamber 322 is a chamber that holds cans 314 while the cans cool to a temperature suitable for handling and processing upon exiting system 310.
In the embodiment shown cooling chamber 322 includes two separate, sub-cooling chambers, shown as unpressurized cooling chamber 323, and unpressurized cooling chamber 325.
As shown in FIG. 1, system 310 includes an induction coil cooling system 330. Induction coil cooling system 330 acts to cool coils 334 and 338 during heating. Cooling of coils 334 and 338 helps to lower the resistance of the material of the coils and consequently also lowers the power consumption during generation of the magnetic fields resulting in higher heating efficiencies. In various embodiments, coil cooling system 330 includes a helical conduit that surrounds coils 334 and 338 and provides a channel for supplying cooling fluid to the outer surface of coils 334 and 338. In one embodiment, the cooling fluid is cooled air, and in another embodiment the cooling fluid is a liquid such as water. After extracting heat from coils 334 and/or 338, the cooling fluid (now heated from coils 334 and/or 338) is redirected to preheating chamber 316 where the extracted heat from the coils acts to raise the temperature within preheating chamber 316. In various embodiments coil cooling system 330 is a refrigeration system (e.g., a compressor-based system), and in this embodiment, induction coil cooling system 330 is a closed circuit moving cooling fluid along coils 334 and 338. In such an embodiment, the heat generated by the components (e.g., the compressor) of the refrigeration system is supplied to preheating chamber 316 via conduit 332 to raise the temperature within preheating chamber 316.
The geometry of coils 334 and 338 may be selected to improve or maximize current induction within cans 314. For example, the coil density (i.e., the number of coil rotations per unit distance), the coil diameter, and the cross-sectional shape of the helical coil (e.g., circular, elliptical, rectangular, square, etc.) may be selected to improve current induction for a particular application. For example, as shown in FIG. 1, coils 334 and 338 are round or circular helical coils. However, in other embodiments other shapes or types of induction coils can be used. For example, in one embodiment, coils 334 and 338 are square or rectangular shaped coils. In addition, in one embodiment, the cross-sectional geometry of the induction coil is a non-regular shape.
While FIG. 17, shows system 310 including two separate heating sections, system 310 may include more or less than two heating sections. System 310 may include more than two heating sections to heat products that require, for example, higher heating temperatures, longer heating times and/or alternating cycles of high heat, low heat and/or no heat. In other embodiments, system 310 may include a single heating chamber, such as either heating chamber 318 or 320, configured to heat cans 314 to the desired temperature for a particular product or application.
In steam based heating systems multiple chambers at different pressures are typically needed because pressure and temperature are interrelated in steam based heating systems (e.g., higher temperature produces higher pressure). In contrast to steam systems, system 310 utilizing induction coil heating allows that the temperature of cans 314 to be controlled (e.g., actively controlled) independent of pressure within the heating chamber. Thus, system 310 allows the heating chamber not to be pressurized, e.g., no overpressure. Because the heating temperature within the induction coil-based heating chambers is not dependent on an elevated pressure within the heating chamber, use of the induction heating coils discussed herein allows for the heating chamber to be unpressurized.
System 310 is configured to provide efficient heating of cans 314 utilizing one or more induction coils, such as coil 334 or coil 338. For example, as discussed above, conduits 328 and 332 transfer excess heat from other sections of system 310 into preheating chamber 316 to preheat cans 314 prior to entry to the main heating chambers.
In addition, conveyor 312 may be configured to facilitate transfer of heat from the can body and/or end walls of cans 314 through the contents of can 314. In one embodiment, conveyor 312 is configured to cause rotation of cans 314 about the longitudinal axis of each can, as cans 314 move through at least heating sections 318 and 320. It should be understood, that as used herein the longitudinal axis of cans 314 is the axis of the can perpendicular to and passing through the center point of the can end wall of each can. In various embodiments, conveyor 312 may be configured to rotate cans about the can's longitudinal axis at relatively fast rotational rates.
In addition, conveyor 312 may be configured to oscillate or agitate cans 314 to facilitate heat transfer within the contents of the can. The oscillation or agitation generated by conveyor 312 may be provided in addition to or in place of rotation of cans 314. In one embodiment, conveyor 312 is configured to cause end over tumbling and/or twisting of cans 314 as cans move along conveyor 312.
In various embodiments, system 310 is configured to orient cans 314 within induction coils 334 and 338 and consequently, to orient cans 314 relative to the magnetic field generated by the induction coils 334 and 338 in a manner that increases the heating efficiency between the interaction of the magnetic field and the electrically conductive metal material of cans 314. FIG. 17 depicts an exemplary embodiment of one such orientation. As shown in FIG. 17, cans 314 are positioned such that the longitudinal axis of cans 314 is substantially perpendicular (e.g., within 10 degrees of perpendicular, and in another embodiment, within 5 degrees of perpendicular) to the longitudinal axis of coils 334 and 338. It is believed that this orientation exposes a greater volume of metal within the body and end walls of cans 314 to interaction (i.e., magnetic coupling) with the magnetic fields generated by coils 334 and 338 which in turns results in results in better can heating than some other potential orientations.
Cans and containers discussed herein may include containers of any style, shape, size, etc. For example, the containers discussed herein may be shaped such that cross-sections taken perpendicular to the longitudinal axis of the container are generally circular. However, in other embodiments the sidewall of the containers discussed herein may be shaped in a variety of ways (e.g., having other non-polygonal cross-sections, as a rectangular prism, a polygonal prism, any number of irregular shapes, etc.) as may be desirable for different applications or aesthetic reasons. In various embodiments, the sidewall of cans 14 may include one or more axially extending sidewall sections that are curved radially inwardly or outwardly such that the diameter of the can is different at different places along the axial length of the can, and such curved sections may be smooth continuous curved sections. In one embodiment, cans 14, such as can 154, may be hourglass shaped. Cans 14 may be of various sizes (e.g., 3 oz., 8 oz., 12 oz., 15 oz., 28 oz, etc.) as desired for a particular application.
In various embodiments, the can ends described above may be various different types of can ends (e.g., a closure, lid, cap, cover, top, end, can end, sanitary end, “pop-top”, “pull top”, convenience end, convenience lid, pull-off end, easy open end, “EZO” end, etc.). The can end end may be any element that allows the container to be sealed such that the container is capable of maintaining a hermetic seal. Various embodiments of can ends may have various different mechanisms for opening and/or removal. In an exemplary embodiment, the upper can end may be an “EZO” convenience end, sold under the trademark “Quick Top” by Silgan Containers Corp.
The can ends 52 and 126 shown in FIGS. 7-11 coupled to the sidewall via a “double seam” formed from the interlocked portions of material of the can sidewall and the can end. However, in other embodiments, the can ends discussed herein may be coupled to the sidewall via other mechanisms. For example, can ends may be coupled to the sidewall via welds or solders.
In various embodiments, the can end 52 may be a closure or lid attached to the body sidewall mechanically (e.g., snap on/off closures, twist on/off closures, tamper-proof closures, snap on/twist off closures, etc.). In another embodiment, the can end 52 may be coupled to the container body via the pressure differential. The container end may be made of metals, such as steel or aluminum, metal foil, plastics, composites, or combinations of these materials. In various embodiments, the can ends, double seams, and sidewall of the container are adapted to maintain a hermetic seal after the container is filled and sealed.
The containers discussed herein may be used to hold perishable materials (e.g., food, drink, pet food, milk-based products, etc.). It should be understood that the phrase “food” used to describe various embodiments of this disclosure may refer to dry food, moist food, powder, liquid, or any other drinkable or edible material, regardless of nutritional value. In other embodiments, the containers discussed herein may be used to hold non-perishable materials or non-food materials. In various embodiments, the containers discussed herein may contain a product that is packed in liquid that is drained from the product prior to use. For example, the containers discussed herein may contain vegetables, pasta or meats packed in a liquid such as water, brine, or oil.
According to various exemplary embodiments, the inner surfaces of the can ends, end panels, and the sidewall may include a liner (e.g., an insert, coating, lining, a protective coating, sealant, etc.). The protective coating acts to protect the material of the container from degradation that may be caused by the contents of the container. In an exemplary embodiment, the protective coating may be a coating that may be applied via spraying or any other suitable method. Different coatings may be provided for different food applications. For example, the liner or coating may be selected to protect the material of the container from acidic contents, such as carbonated beverages, tomatoes, tomato pastes/sauces, etc. The coating material may be a vinyl, polyester, epoxy, EVOH and/or other suitable lining material or spray. The interior surfaces of the container ends may also be coated with a protective coating as described above.
It should be understood that the figures illustrate the exemplary embodiments in detail, and it should be understood that the present application is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology is for the purpose of description only and should not be regarded as limiting.
Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only. The construction and arrangements, shown in the various exemplary embodiments, are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. Some elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process, logical algorithm, or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present invention.
While the current application recites particular combinations of features in the claims appended hereto, various embodiments of the invention relate to any combination of any of the features described herein whether or not such combination is currently claimed, and any such combination of features may be claimed in this or future applications. Any of the features, elements, or components of any of the exemplary embodiments discussed above may be used alone or in combination with any of the features, elements, or components of any of the other embodiments discussed above.

Claims

What is claimed is:

1. A metal can body comprising:

a cylindrical, metal sidewall having a circular cross-section which defines a volume;

a circular, metal end panel that closes one end of the cylindrical sidewall, the end panel including:

a circular center panel having a perimeter defined by a bead and a first plane contacting a surface of the panel;

an annular, elastic portion extending from the sidewall to a boundary and having a second plane substantially perpendicular to the sidewall and contacting the elastic portion, the elastic portion including a plurality of ridges substantially concentric with the sidewall;

a frustoconical transition portion extending from the boundary to the bead connecting the center panel and the elastic portion such that the first plane is offset from the second plane to support the center panel at a first position in the interior;

the center panel being moveable from the first position to a second position by a force exerted from the interior upon the end panel, the second position being outside of the volume, and the center panel returnable to the first position when the force is reduced.

2. The can body of claim 1, wherein the metal is one of steel and aluminum.

3. The can body of claim 2, wherein the concentric ridges are uniformly spaced.

4. The can body of claim 2, wherein there are at least five ridges in the elastic portion.

5. The can body of claim 4, wherein the sidewall has a first radius from the center of the center panel, the perimeter has a second radius which is between 50% and 60% of the first radius, and the boundary has a third radius between 20% and 30% of the first radius.

6. The can body of claim 5, wherein the transition portion extends from the center panel at an angle of between 17° and 21° when the center panel is in the first position.

7. The can body of claim 4, wherein the metal sidewall and the end panel are joined together at the sidewall with a double seam.

8. The can body of claim 4, wherein the metal sidewall and the end panel are integrally formed.

9. A method of filing a can comprising:

providing a can body having a sidewall extending along a longitudinal axis from a first open end to a second end and an end panel sealing the second end, the end panel having a center panel portion in a first configuration extending along a first plane, a transition portion extending radially outwardly from the center panel portion, and a radially outer elastic portion extending between the transition portion and the sidewall along a second plane, the second plane being non-coplanar with the first plane;

filling the can body;

coupling a can end to the sidewall to hermetically seal the can body;

heating the contents of the sealed can body, wherein the increased pressure inside the can body resulting from the heating causes the center panel portion to transition from the first configuration to a second configuration in which the center panel portion extends along a third plane on an opposite side of the second plane than the first plane;

wherein the second plane and the third plane are non-coplanar;

cooling the contents of the sealed can body; and

applying a force to the center panel portion toward the first plane causing the center panel portion to transition from the second configuration to the first configuration.

10. The method of claim 9, wherein the heating step includes heating the contents of the container by induction.

11. A can body comprising:

a sidewall extending along a longitudinal axis from a first open end to a second end; and

an end panel closing the second end of the sidewall, the end panel including an outer annular portion including a plurality of ridges, a frustoconical portion extending radially inwardly from the outer annular portion at a first angle, and a center portion extending from the frustoconical portion;

wherein the center portion is configured to be displaced between a first configuration in which the center portion is located above the lower axial periphery of the sidewall and a second configuration in which the center portion is located below the lower axial periphery of the sidewall.

12. The can body of claim 11, wherein the end panel has a first diameter and wherein the center portion has a second diameter;

wherein the second diameter is between 20% and 30% of the first diameter.

13. The can body of claim 11, wherein the outer annular portion includes a plurality of ridges generally concentric with the sidewall; and

wherein the center portion has a perimeter defined by a bead generally concentric with the sidewall.

14. The can body of claim 11, wherein the outer annular portion extends along a first plane;

wherein the frustoconical portion extends at a first angle to the first plane when the center portion is in the first configuration; and

wherein the first angle is between 17° and 21°.

15. The can body of claim 11, wherein the can body has a first height;

wherein the center portion in the first configuration extends along a second plane;

wherein the second plane is a second height above the first plane; and

wherein the second height is between 2% and 3% of the first height.

16. The can body of claim 11, wherein the outer annular portion is configured to allow the center portion to transition between the first configuration and the second configuration and to resume its shape prior to the transition after the transition.

17. The can body of claim 11, wherein the center portion is configured to transition from the first configuration to the second configuration when the pressure inside the can body is between 35 psig and 40 psig.

18. The can body of claim 11, wherein the outer annular portion includes six ridges.

19. The can body of claim 11, wherein the end panel is coupled to the sidewall by a double seam.

20. The can body of claim 11, wherein the end panel is configured to allow the center portion to transition between the first configuration and the second configuration without permanently deforming the end panel; and

wherein the end panel is configured so that the center portion is maintained in the second configuration when the interior pressure of the can body decreases.