Patent Grant
8113370
The present disclosure relates to vacuum side panels that control container deformation during reductions in product volume that occur during cooling of a hot-filled product.
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. Plastic containers, such as polyethylene terephthalate (“PET”), have become commonplace for the packaging of liquid products, such as fruit juices and sports drinks, which must be filled into a container while the liquid is hot to provide for adequate and proper sterilization. Because these plastic containers are normally filled with a hot liquid, the product that occupies the container is commonly referred to as a “hot-fill product,” and the container is commonly referred to as a “hot-fill container.” During filling of the container, the product is typically dispensed into the container at a temperature of at least 180° F. Immediately after filling, the container is sealed or capped, such as with a threaded cap, and as the product cools to room temperature, a negative internal pressure or vacuum forms within the sealed container. Although PET containers that are hot-filled have been in use for quite some time, such containers are not without their share of limitations.
One limitation of PET containers that receive a hot-filled product is that during cooling of the liquid product, the containers may undergo an amount of physical distortion. More specifically, a vacuum or negative internal pressure caused by a cooling and contracting internal liquid may cause the container body or sidewalls to deform in unacceptable ways to account for the pressure differential between the space inside of the container and the space outside, or atmosphere surrounding, the container. Containers with deformations are aesthetically unpleasing and may lack mechanical properties to ensure sustained container strength or sustained structural integrity while under a negative pressure.
Another limitation of PET containers that receive a hot-filled product is that they are not easily held by a hand of a handler, such as a consumer who is drinking the product directly from the container. For instance, intended container gripping areas typically located on the body of containers are not designed to conform to a user's hand while also accounting for the above-mentioned pressure differential resulting from hot-filled containers.
Another limitation of plastic containers, such as hot-fill containers, is that such containers may be susceptible to buckling during storage or transit. Typically, to facilitate storage and shipping of PET containers, they are packed in a case arrangement and then the cases are stacked case upon case on pallets. While stacked, each container is subject to buckling and compression upon itself due to direct vertical loading. Such loading may result in container deformation or container rupture, both of which are potentially permanent, which may then render the container and internal product as unsellable or unusable.
Yet another limitation with hot-filled containers lies in preserving the body strength of the container during the cooling process. One way to achieve container body strength is to place a multitude of vertical or horizontal ribs in the container to increase the moment of inertia in the body wall in select places. However, such multitude of ribs increases the amount of plastic material that must be used and thus contributes to the overall weight and size of the container.
The present invention provides a hot-fillable, blow-molded plastic container suitable for receiving a liquid product that is initially delivered into the container at an elevated temperature. The container is subsequently sealed such that liquid product cooling results in a reduced product volume and a reduced pressure within the container. The container is lightweight compared to containers of similar size yet controllably accommodates the vacuum pressure created in the container. Moreover, the container provides excellent structural integrity and resistance to top loading from weight placed on top of the container.
Possessing a central vertical and a central horizontal axis, as well as a body or sidewall central horizontal axis, the container structure further employs an upper portion defining a mouth, a shoulder portion that is formed with and molded into the upper portion and that extends downward from the upper portion, a bottom portion forming a base, and a body or sidewall that extends between and joins the shoulder portion and the bottom portion. The sidewall further defines a pair of opposing columns that are oriented diagonally relative to the base and that are concave inward toward the container central vertical axis when the container is not sealed or filled with a liquid. When filled with a hot liquid that is then cooled, the opposing columns become concave inward to a lesser extent because the container interior undergoes and sustains an interior vacuum. Moreover, the body or sidewall defines a pair of opposing vacuum panels that are oriented diagonally relative to the base and that are formed with compound angles to conform to a palm of a human hand. A vacuum initiator, also called a hinge or groove, is coincident with a vacuum panel longitudinal centerline and is formed as part of each of the pair of opposing vacuum panels.
The vacuum initiator or groove may further define vacuum initiator walls such that upon contraction of the container liquid content, the groove walls initiate movement toward the container central vertical axis. The walls of the vacuum panels are parallel to each other at approximately a horizontal centerline of the sidewall or vacuum panel structure when viewed as a container cross section.
The bottom portion may have a circumferential base recession or groove, which may be horizontal and define base groove walls. The base groove may be formed outside of the vacuum panel area and at a sufficient depth to permit vertical movement of the shoulder groove walls, and thus, the container. Similarly, the shoulder of the container may define a circumferential shoulder groove defining shoulder groove walls. The shoulder groove may be horizontal and at a sufficient depth to permit vertical movement of the shoulder groove walls, and thus, the container.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
Referring now to
Since the container 10 is designed for “hot-fill” applications, the container 10 is manufactured out of a plastic material, such as polyethylene terephthalate (“PET”), and is heat set such that the container 10 is able to withstand the entire hot-fill procedure without undergoing uncontrolled or unconstrained distortions. Such distortions may result from either or both of the temperature and pressure during the initial hot-filling operation or the subsequent partial evacuation of the container's interior as a result of cooling of the product. During the hot-fill process, the product may be, for example, heated to a temperature of about 180 degrees Fahrenheit or above and dispensed into the already formed container 10 at these elevated temperatures.
As depicted in
Extending between the shoulder portion 16 and the bottom portion 18 is a sidewall or body 24 of the container 10. As depicted in
Before continuing with a description of the container sidewall 24, a brief description of the shoulder portion 16 and bottom portion 18 will be provided. The container shoulder portion 16 is generally of a conical shape with a narrower cross section that joins or forms into the upper portion 12 while the opposite end of the shoulder portion 16 has a larger cross section and meets with the sidewall 24. The shoulder portion 16 may be equipped with one or more recessed ribs or grooves that are circular or elliptical, such as groove 38 and groove 40. Between the shoulder portion 16 and the sidewall 24, a transition groove 42 may exist. The grooves 38, 40, 42 may have groove walls. For instance, groove 38 may have groove walls 44, 46, groove 40 may have groove walls 48, 50, and groove 42 may have groove walls 52, 54. As depicted in
There are advantages to the grooves 38, 40, 42 and 60. For instance, because the grooves are formed by their respective groove walls, as noted above, which project toward a container interior volume, additional strength is added to the container sidewall 24 because the material's moment of inertia is increased at the location of the grooves 38, 40, 42 and 60. The grooves 38, 40, 42 and 60 are also known as strengthening ribs 38, 40, 42 and 60. There is another advantage to the grooves 38, 40, 42 and 60, and in particular, groove 42 and groove 60. The horizontally arranged grooves 42, 60 are able to receive and absorb a vertically-applied, compressive load 23, such as may be imparted on the container cap 20 when the container 10 is part of a case or pallet of containers, which may then become top-loaded with another case or pallet of containers. Because the container 10 contains the horizontal grooves 42 and 60, the container 10 will not buckle under a shock load of a case or pallet of containers, when applied within container buckling limits. Although grooves 38, 40 are not horizontally arranged, they are still capable of absorbing vertical loading, especially in instances such as when one case or pallet of containers is released onto another case or pallet of containers, as in the case of an initial shock load. In such a scenario, buckling may be prevented. Additionally, the grooves 38, 40 act as strengthening ribs and provided circumferential strength to the shoulder portion 16 of the container 10.
A description of the container sidewall 24 will now be presented.
The first and second vacuum panels 30, 32 exhibit a generally inward, arcuate shape from top to bottom between the shoulder portion 16 and the bottom portion 18, as depicted in
As depicted in
The first vacuum panel 30 is equipped with a first vacuum panel hinge or groove 68, also known as a first vacuum panel initiator 68 or simply as a first initiator 68. Similarly, the second vacuum panel 32 is equipped with a second vacuum panel hinge or groove 70, also known as a second vacuum panel initiator 70 or second initiator 70. The first and second initiators 68, 70 are called such because upon a liquid 11 beginning to cool within the container 10, the volume of the container 10 will begin to be increasingly displaced due to the contraction of the container 10 along the first and second initiators 68, 70. Thus, the first and second initiators 68, 70 are the locations within the first and second vacuum panels 30, 32 of the sidewall 24 where the vacuum within the container 10 begins to alter the position of the vacuum panels 30, 32 just before the balance of the vacuum panels 30, 32 begins to move. More specifically, the walls 74 of the first initiator 68 and the walls 76 of the second initiator 70 will begin to be drawn toward the interior of the container 10, such as toward the container central vertical axis 78, as depicted with phantom lines 80, 82. Upon initial movement of the first and second initiators 68, 70, the balance of the vacuum panels 30, 32, beginning with the portions closest to the initiators 68, 70, will then begin to move toward the central vertical axis 78, that is, toward an interior of the volume of the container 10.
Separating the first vacuum panel 30 from the second vacuum panel 32 is the pair of diametrically opposed columns 34, 36 and it is the placement and shape of the columns 34, 36 relative to the vacuum panels 30, 32 which, in one instance, permits the vacuum panels 30, 32 to move toward the central vertical axis 78 and to cause the columns 34, 36 to move away from the central vertical axis 78. Located on opposing sides of the container 10, the columns 34, 36 are depicted in
As depicted best in
As depicted best in
The transition between the columns 34, 36 and the vacuum panels 30, 32 is a step downward of sorts, or rather a decrease in the radial distance to the central vertical axis 78, as is evident in
The container 10 as previously described generally addresses the container 10 as it is originally formed. The discussion will now focus on changes in the structure after hot-filling the container 10. After a hot liquid product 11 is filled into the container 10, the container 10 is immediately capped and begins cooling, and thus the product within the container 10 begins decreasing in volume. This reduction in product volume produces a reduction in pressure within the container 10 and begins to exert forces on the interior wall(s) of the container 10. The vacuum panels 30, 32 of the container 10 controllably accommodate this pressure reduction by being pulled or contracted inward toward the central vertical axis 78, as depicted using phantom lines 80, 82 in
As the vacuum panels 30, 32 move or contract inwardly toward the central vertical axis 78, the generally circular shape of the body or sidewall 24 permits or causes the columns 34, 36 to deflect radially outward from their non-filled position and into a more upright orientation. This phenomenon is depicted with phantom lines 84, 86 in
Because of the significant reduction in vacuum pressure of the container 10 after cooling, the container 10 has a greater propensity to not retain outwardly induced, but inwardly directed, dents which normally occur during handling or shipping. Containers with higher resultant vacuum pressures (and therefore less vacuum accommodation) tend to retain or hold such dents as a result of the vacuum forces themselves. The novel shape of the container 10 further lends the container 10 to light weighting as the vacuum panels 30, 32, given their orientation, require less material than if a circular sidewall were used in their place.
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