PT1163161E - A container having pressure responsive panels - Google Patents

Description

Description " Container with Pressure Reacting Panels "

Technical Field The present invention relates to a pressure adjustable container and more particularly to polyester containers filled with a hot liquid, and to an improved side wall construction for such containers.

Background of the invention

Hot fill applications impose significant and complex mechanical stresses on a vessel structure due to thermal stress, hydraulic pressure during filling and after capping, and vacuum pressure as the fluid cools. The thermal stress is applied to the walls of the container during the introduction of the hot fluid. The hot fluid will cause the walls of the container to soften and then shrink non-uniformly, causing distortion of the container. The polyester therefore has to be thermally treated to induce molecular alterations resulting in a vessel exhibiting thermal stability. The pressure and tension act on the side walls of a heat resistant container during the filling process, and for a subsequent period of time. time after irccv When the vessel is filled with a hot Mipiido, and sealed, there is a pressure. . ih being an increasing internal pressure applied to the vessel.

As the liquid, and the air gap below the cap subsequently cools, the thermal shrinkage results in the partial evacuation of the vessel. The vacuum created by cooling tends to mechanically deform the walls of the vessel.

Generally speaking, containers incorporating several longitudinal flat surfaces accommodate vacuum forces more easily. Agrawal et al, U.S. Patent 4,497,855 discloses a container with a plurality of recess collapsed panels separated by contact surfaces which permit uniform deformation to the interior under the force of the vacuum. The effects of the vacuum are controlled without adversely affecting the appearance of the container. The panels are drawn inwardly to ventilate the internal vacuum and thus prevent excess force from being applied to the container structure, which would otherwise deform the structures of the inflexible supports and contact surfaces. The amount of " flexion " available in each panel is however limited and as the boundary approaches there is an increasing amount of force which is transferred to the sidewalls.

To minimize the effect of the force being transferred to the sidewalls, much of the prior art is focused on providing the vessel with reinforced regions, including the pMMs to prevent the structure from plastically deforming under vacuum force.

EP > in which the preamble of claim 1 is based, proposes the partial solution to this problem using a continuous integral hinge structure surrounding the panel. The provision of horizontal or vertical annular sections, or " ribs " through the container has become a common practice in the construction of containers, and is not restricted to hot-fill containers only. Such annular sections will reinforce the part where they are placed. U.S. Patent 4,372,455 to Cochran discloses reinforcement through annular ribs in a longitudinal direction placed in the areas between planar surfaces which are subjected to bostrostic forces which deform inwardly under the force of the vacuum. U.S. Patent 4,805,788 to Akiho Cta discloses ribs which extend longitudinally along the panels to add reinforcement to the container. Akiho Ota also describes the reinforcing effect by providing a larger pitch on the sides of the contact surfaces. This provides greater dimension and strength to the areas of the ribs between the panels. Akiho Ota et al in US Pat. No. 5,178,290 discloses notches to strengthen the panels' own areas.

Akiho Ota et al., U.S. Patent 5,238,129 discloses additional annular grinding wheels, which are recessed horizontally in strips above and below and on the outside of the portion of the hot-filler panel of the bottle.

In addition to the need to reinforce a container both against thermal stress and vacuum, there is a need to allow an initial hydraulic pressure and increasing internal pressure which is placed in a vessel when the hot liquid is introduced followed by the capping. This causes tension to be placed on the side wall of the container. There is a forced outward movement of the heated panels, which may result in container packing.

Thus, Hayashi et al in U.S. patent 4,877,141 describes a panel configuration which accommodates an initial, natural, outward flexing caused by hydraulic pressure and internal temperature, followed by inward flexing caused by the formation of vacuum during cooling. More importantly, the panel is held relatively flat in the profile but with a central shift slightly offset to add reinforcement to the panel but without impeding its radial movement into the interior and exterior. With the panel generally being flat, however, the amount of movement is limited in both directions. Of necessity, the panel ribs are not included for additional elasticity, as this would prevent movement of the panel to the outside of the panel as a whole. we

Krishnakumar et al. In US Pat. No. 5,908,128 discloses a further flexible panel which is intended to react to hydraulic pressure and temperature forces occurring after filling. A " hot fill " style container geometry " relatively normalized to a " pasteurizable " container. It is understood that the pasteurizing process does not require the container to be hot-set prior to filling because the liquid is introduced cold and is heated after the capping. Concave panels are used to compensate for pressure differences. To provide yet flexibility in both the radial outward movement followed by the radially inward movement, the panels are maintained in a curvature inwardly to accommodate a response to internal pressure and changing temperatures of the pasteurizing processes. The increase in temperature after the capping, which is maintained for some time, softens the plastic material and thereby allows the curved panels into the interior to flick more easily under the induced force. It is described that too much bend would still prevent this. The permanent deformation of the panels when forced for a bending bend is avoided by adjusting the superficiality of the bend, and by softening the material under heat. The amount of force imparted to the walls of the container is therefore again determined by the amount of flexing available, such as occurs in a standard hot-fill bottle. The amount of flexure is limited, due to the need to maintain a curvature on the radial profile of the panels. Thus, the bottle is reinforced in various standard modes.

Kríshnakumar et al, in U.S. patent 5,303,834 further further describes " flexible " panels " which can be moved from a convex position into a concave position by providing a " compressible " container. Only the vacuum pressure can not reverse the panels, but they can be manually forced to reverse. The " panels " automatically to its original shape during release of the compression pressure, since a significant amount of force is required to keep them in an inverted position, and this has to be maintained manually. The permanent deformation of the panel caused by the initial convex presentation is avoided by the use of several longitudinal bending points.

Krishnakumar et al., In U.S. Pat. No. 5,971,184 further describes " flexible " panels " which claim to be immovable from a first convex position to a second concave position a3 provide a squeeze bottle comprising two large flattened sides, each panel having the central one that is intended to be " invertible ". Containers of this kind, in which there are two opposite sides of large pianos, differ in the stability of the pressure of the vessel from filling containers in which it is intended to provide a generally cylindrical shape under vacuum drawing. The enlarged panel side walls are subjected to increasing suction; and are drawn into a larger concavity than if each panel were smaller in dimension, such as occurs in a " normal " which comprises six panels in a substantially cylindrical vessel. Accordingly, such a container structure increases the amount of force supplied to each of the two panels, thereby increasing the amount of bending force available.

Even so, the convex section of the panels has however still to be held relatively flat, or the force of the vacuum can not pull the panels to the required concavity. The need to maintain a curvature surface to allow flexing to occur has previously been described by Krishnakumar et al in U.S. Patents 5,303,834 and 5,908,128. This in turn limits the amount of vacuum force that is vented before a deformation is applied to the vessel walls. Additionally, it is generally considered impossible for a shape that is convex in both the longitudinal and horizontal planes to successfully reverse, however, unless it exhibits a surface convexity. Still further, the panels can not then return back to their original convex wall after the release pressure is released when the lid is removed if there is any significant amount of convexity in the panels. In the best case, a panel will be subject to being deflected to the gallows and will remain locked in a new inverted patiyát. The panel will then not be able to and reverse the direction of theac that no longer exists. the liquid heat to soften the material and there is sufficient available ambient pressure strength. In addition, there is no more memory force support available on the plastic before being deflected to a concave position. Krishnakumar et al in U.S. Patent 5,908,128 describes priorly the placement of longitudinal ribs to prevent such permanent deformation from occurring when the panel arches are bent from a convex to a concave position. This same observation with regard to permanent deformation has also been described in Krishnakumar et al in U.S. Patent 5,303,834. Hayashi et al. In U.S. Patent 4,877,141 also describes the need to maintain relatively flat panels if they have to be bent against their natural curve. The inventors believe that the main mode of failure in prior art containers is the irrecoverable deformation of the structural geometry of the container, due to the weakness, that there is a vacuum pressure inside the container and especially when such a container has been at one The present invention allows by way of an increasing view of the side walls of the under-floor panel, such that the pressure in the walls of the panel is lowered. containers can be more easily accommodated. Reinforcing ribs of various types may also be used at locations as described above to further compensate for any excess tension which must inevitably be present from the flexing of the vessel walls to a new pressure-adjusted condition by ambient forces.

Object of the invention

Accordingly, it is an object of the invention to overcome or at least lessen such problems in containers at present, or at least to provide the public with a useful choice.

Additional objects of the present invention will become apparent from the following description.

SUMMARY OF THE INVENTION

According to the present invention, there is provided a container according to claim 1.

In a preferred embodiment, the blades project in an outwardly directed direction relative to the piano.

In another preferred embodiment, the zones project inwardly relative to the plane. the preferred flexible lidded panel may be substantially

In an alternative embodiment, the flexible panel may comprise two portions of flexible panels that meet at a vertex.

Preferably, the flexible panel may be located between relatively inflexible contact surfaces.

In a preferred embodiment, the or each primer initiator may be located substantially at one end of said flexible panel.

In an alternative embodiment, the initiator portion may be located substantially towards a center of said flexible panel.

Preferably, the or each primer portion may comprise a substantially flattened change.

Preferably, the flat portion may be located at a distal end of said initiator portion relative to the rest of the flexible panel.

In a preferred embodiment, the or each primer portion may project in an opposing direction to the remainder of the flexible panel.

Preferably, a boundary between said initiator portion and the remainder of said flexible panel may be substantially arcuate in the circumferential direction of the panel.

In a preferred embodiment, the extent of the panel projection could be progressively moved away from said initiating portion. alternative, the extension of

In one embodiment, the flexible panel may remain substantially constant away from said initiator portion.

The container is preferably comprised of a connector portion between said flexible panel and said contacting surfaces, the connector portion adapted to locate said flexible panel and said contact surfaces on a different circumference relative to a center of the container.

Preferably, the connector portion may have a shape substantially in " U ", wherein the side of the connector portion towards the flexible panel is adapted to flex, substantially straightening the shape in " U " when the flexible panel is in a first position and returning to the shape in " U " when the flexible panel is inverted from the first position.

Preferably, the extent of the projection of the initiator portion may be adapted to permit deflection of the initiator portion during cooling of a predetermined liquid entering the vessel at a predetermined temperature.

Of course, the flexible panel can be adapted to be placed in perspective during the course of the initiator portion.

Further preferred are described in the accompanying drawings.

Further aspects of the invention will become apparent from the following description by way of example only in which reference is made to the accompanying drawings.

Brief description of the drawings

Figure 1 is a top view of a container according to a possible embodiment of the present invention.

Figure 2a shows the top section of the container panel shown in figure 1.

Figure 2b side view of the panel cutout shown in Figure 2a.

Figure 3 is a side view of the panel cutout shown in figure 2b inverted.

Figures 4a-c are schematic cross-sectional representations of the container of Figure 1 along lines A-C respectively when the panel cuts are not inverted.

Figures 5a-c are schematic cross-sectional representations of the container of Figure 1 a3 along lines A-C respectively when the panel cuts are inverted.

Figures 6a-c and 4b are alternate side embodiments of one panel.

Figure 7 is a elevated front view of a further alternative embodiment of a section of the panel.

Figures 7b, c are side views and a section of the panel of Figure 7a respectively in the non-inverted and inverted positions.

Figure 8 is a elevated front view of a further alternative embodiment of a panel cutout.

Figures 8b-d are side views of a section of the panel of Figure 8a in a non-inverted, partially inverted and fully inverted position, respectively.

Figures 9a-c and Figures d-f cross-sectional cross-sectional views through lines corresponding to A-C respectively of the container of Figure 1 showing an additional alternative panel section respectively in non-inverted and inverted positions.

Detailed description of the drawings

Referring to Figure 1, according to a preferred form of the present invention, the container is generally marked at 1 as having a wall section 2 the container 1 and a pressure adjustable container, in particular a hot-fill container which is adapted to be filled with a liquid at a temperature above room temperature. The container 1 may be formed of a blown mold and may be produced from a polyester or other plastic material, such as a hot-set polyethylene terephthalate (PET). The underside of the sidewall portion 2 comprises a number of vertically oriented elongated vacuum panels 3 which are disposed around the circumference of the container spaced from one another by vertically elongated, smooth contact surfaces 4. Each panel may be generally rectangular in shape and is adapted to flex inwardly during filling the container with a hot fill liquid, capping the container, and subsequent cooling of the liquid. During the process the vacuum panels 3 operate to compensate for the hot filling vacuum.

Referring now to Figure 2a, there is shown a vacuum panel 3 of the container 1. Vacuum panel 3 comprises at least one connecting portion 7 connecting a projection change 5 to the surfaces of the contact 4. The projection portion 5 comprises m. which controls the joint of the projection portion 5 and the connecting portion 7. Preferably, the connecting portion 5 is foldable inwardly under the force of relative ease and the initiator portion 8 causes that the projecting portion 5 deflects by inversion and then flexes further inwardly. This causes a much greater evacuation of the volume of the vacuum panels 3 than the existing flex panels. The vacuum pressure is subsequently reduced to a greater degree than in the existing containers so that less tension is applied to the side walls of the container.

Preferably, the connecting portion 7 allows the radius of the center of the container 1 on the edge of the flexible panel 3 (within the connecting portion 7) to be adjusted independently of the radius at the edge of the contact surfaces 4 (outer edge surrounding the connecting section 7). Thus, the connecting portion 7 allows the contact surface 4 to be independently complete on one side, and that the flexible panel 3 is complete, and optimized, for deflection on the other side. The connecting portion 7 overcomes any circumferential radial difference between the two structures. The boundary between the initiating portion 8 and the remainder of the projecting portion 5 is shown to be substantially shelved in the circumferential direction of the panel 3. The amount of arc or projection of the initiating portion 8 relative to a plane defined by the center longitudinal axis is significantly smaller than the arc or projection to the projecting portion 5, making it more susceptible to the pressure of the tetter. The starter portion 8 further comprises a starter end 9 which is predominantly flattened and is more susceptible to the pressure of the tetter. , when the container 1 is subjected to vacuum pressure, the vacuum panel 3 may flex the portion 9 of the end of the initiator, followed by deflection and then inversion of the entire initiating portion 8 and subsequent inflation of the reversal of the projection portion 5. In an alternate embodiment, the end 9 of the initiator may be concave. However, in this embodiment the extent of the projection of the concave portion relative to a plane defined by the central axis of the container and even smaller than the magnitude of the projection of the remainder of the projecting change 5,

It will be appreciated that the reversal of the projecting portion 5 can progress regularly in response to gradual contraction of the volume of the contents of the vessel 1 during cooling. This is in contrast to a panel that " deflect " between two states, & the gradual deflection of the projecting portion 5 to and from the inversion in response to a relatively small pressure differential compared to the panels which " deflect ", means that the same is transmitted to the side walls of the vessel I. This allows material to be necessarily used less in the container, for greater production, less damage may occur under load for the same amount of material as the container.

In addition, the reduced pressure differential required to reverse the projecting change 5 allows a larger number of panels 3 to be included in a single container 1i. The panel 3 also does not need to be large in dimension as it provides a low vacuum force to initiate panel flexion. Thus, the panels 3 do not have to be large in size nor reduced in number in a container structure, providing more flexibility in the design of the container. Figure 2b shows a cross-section along line DD in figure 2a. The panel 3 is shown with a projecting section 5 in a non-inverted position, the line dotted with the boundary of the projection section 5 with the connecting section 7. In the preferred embodiment of the invention, the projecting section 5 is substantially arcuate in a radially outward or transverse direction, as indicated by the direction arrow 6. The connecting portion 7 has a shape substantially in " U " with the relative heights of the sides or determining the relative radius at which the contact surfaces 4 and the projecting section 5 are positioned. The end 9 of the initiator is more susceptible to vacuum pressure due to projecting less, i.e., presenting the smaller arc of the projection portion 5. Fig. 3 shows a panel 3 cm the fear of the projection 5 inverted due to the forces of applied force. The end 9 of the primer and primer% reverses first, effectively pulling the contiguous area of the portion 5 of the projection inwardly. This continues along the projecting change 5 until the protruding section is fully inverted as shown in 5b. The dotted line in figure 3 will show the edge of the projecting section 5 and the dotted line 5a shows the position of the projecting section 5 when not inverted. What is important is when the vacuum pressure is released followed by removal of the container lid, the panel 3 is capable of recovering from the assumed vacuum position and returning to its original configuration. This can be supported by a uniform gradation of the arc of curvature from one end of the projecting section 5 to the other, increasing the arc of curvature progressively away from the initiator portion 8. When the pressure is released, the initiating portion 8 causes the panel arcuate 3 inwardly successfully inverts transversely the direction, starting with the reversal of the initiating change 8 and followed by the projecting section 5 which rises without being subjected to non-recoverable deformation. The vacuum panel 3 may repeatedly reverse without significant permanent deformation. Figures 4a-c show representations of '-; of the container 1 shown in Figure I along the lines Mf BB, and CC respectively with the projecting portions 5 in the non-inverted position. In this preferred embodiment, the projecting portion 5 projects further progressively outwardly away from the initiator portion 8.

Figures 5a-c show cross-sectional representations of the container 1 away from the lines Ad, BB, and CC respectively with the projecting change 5 in the fully inverted position, 5b, due to the applied vacuum pressure. The area of the projecting portion 5 about the line AA deflects to a relatively large extent compared to the areas proximate to the initiator portion 8. The dotted lines 5a in Figures 5a-c indicate the position of the projecting twigs 5 without vacuum pressure. Figure 6a shows an elevation of an alternate embodiment of a vacuum panel 30 with a starter portion 80 and flattened area 90. The vacuum panel connector portion 70 is a flat member that surrounds the projecting portion 50. A figure 6b shows the vacuum panel 30 without the vacuum pressure applied. The projecting section 50 has a substantially constant arc of curvature remote from the initiator 80 in the direction of the arrow 6. Figure 6c shows a vacuum panel 30 with its change 10 in a fully controlled position due to the predolation of the vacuum Figure 7a shows the results of the embodiment and the additional embodiment of an elevator panel 300. The elevator panel 300 comprises two sections that are located vertically adjacent to one another. The primer portion 800 extends in two directions at one end of the central initiator 900. In this embodiment, the center of the vacuum panel 300 is more susceptible to deflection on the vapor pressure thus deflecting first. Figures Tp and 7c show a vacuum panel 300 without vacuum pressure respectively applied in the fully inverted position. The dotted line 80Ca illustrates the arcuate boundary between the initiator portions 800 and the remainder of the projecting portions 500. Figure 8a shows an elevation of a further alternative embodiment of a generally indicated vacuum panel with the arrow 300 ' . Vacuum panel 300 'comprises two projecting portions 500' and 500a located vertically adjacent to each other with respective primer portions 800x including a central flat zone 900% therebetween. However, unlike the vacuum panel 300, the nominal position of one of the projecting portions 500a is concave instead of convex (Figure 8b). When applying the hydraulic pressure, the projecting concave portion SCK%: is inverted in the direction shown by the arrow 6a (see Figure 8c), reducing the pressure on the contact surfaces (4) between contiguous pitities 300%. As soon as the fluid cools, the pressure of vacuum causes both projecting portions 500x and Figure 8d). 500 "are reversed in 6B. (Look

It will be appreciated that the profile and / or configuration of the vacuum panels can be varied. For example, as shown in Figure 9, the container (1) may have vacuum panels with projecting portions 5 'including two flat portions 10 which meet at a vertex 11 so as to form an angular panel, as opposed to a arched. Figures 9a-c show cross-sections along the lines AA, EB and CC respectively of the container 1 of figure 1 but with such projecting portions S 'Figures 9d-f respectively show the inverted positions of the projecting sections 51 of Figures 9a-c, with the filled lines 5xb showing the inverted position and the dotted lines 51a the positions before the inversion. Additionally, or alternatively, panels 3 of any of the embodiments may be positioned transversely of the longitudinal axis of the container 1 rather than vertically such as for example shown in Figure 1.

Thereby, an adjustable container is provided which comprises flexible panels allowing a large change in the volume of the contents of the container, whereby reduced pressure is applied to the side walls. Consequently, is the reduced content of material necessary for it? the integrity of the container, and the container can thus be cheaper in manufacture.

With reference to the foregoing description, reference has been made to specific or all components of the invention having known equivalents. The equivalents are incorporated herein by reference.

Although the present invention has been described by way of example and with reference to possible embodiments thereof, it should be understood that modifications or improvements may be made thereto without departing from the scope of the invention as defined in the appended claims.

Lisbon, July 30, 2007

Claims (24)

Container (1) suitable for containing liquids and having at least the flexible deflected control legs (3) to accommodate < (3) has longitudinal and transverse extensions defining a plane of said flexible panel (3), said extensions being longitudinal and transverse with respect to a longitudinal axis of said container , said flexible panel (3) having a bending region (5) projecting away from said plane, characterized in that said panel has a bending initiation zone (8) positioned longitudinally spaced from said bending zone (5); ), said bending initiating zone having a smaller amount of bending projecting away from said plane than said bending zone (5), said regions longitudinally joining each other within the panel with the amount of bending progressively increasing from said first zone to said bending zone and said zone (8) in response to the pressure changes the amount of bending changes and causes said bending zone (5) to progressively decrease in said amount and bending in response to increasing pressure change in the bending container. Container according to claim 1, characterized in that said flexure zone (5) projects outwardly in a transverse direction relative to said longitudinal axis. Container according to claim 1 or 2, characterized in that said flexing of said flexure zone (5) results in a decrease in the curvature outwardly from said outward projection of said flexure zone (5). Container according to claim 1, 2 or 3 characterized in that said initiator zone (8) has an outward curvature which is uniformly joined with said flexure zone (5). Container according to claim 1, 2 or 3, characterized in that said initiating zone (8) has an inner periphery which joins uniformly with said bending zone. A container according to claim 1, characterized in that an extension of said arc relative to said plane varies along an axis of said container (i). Container according to claim 1, characterized in that said initiating zone (8) varies in an extent which radiates three-sidedly along said longitudinal axis of said container (1). Container according to claim 7, characterized in that said flexure zone (5) varies in an extent that radiates transversely along said longitudinal axis of said container (1). Container according to claim 7, characterized in that the zone of the initiator (8) reverses in order to reverse in a curvature in response to a change of vacuum pressure inside the container (1). A container according to claim 9, characterized in that said flexure zone (5) reverses so as to revert in the curvature in response to the vacuum pressure change within said container (1). A container according to claim 1, characterized in that said container (1) is adapted to contain liquid at an elevated temperature above room temperature, said flexible panel (3) being adapted to invert in the case of a change in the internal pressure during the change in temperature of said liquid, characterized in that said initiating zone (8) is adapted to revert with respect to the direction of its projection thereby causing said bending zone (5) to revert relative to direction of its projection. A container according to claim 11, characterized in that said flexible panel (3) is adapted to flex inwardly in the event of a decrease of internal pressure during cooling of said liquid. Container according to claim 1, characterized in that said amount of bending is in an outward direction relative to said plane. A container according to claim 13, characterized in that said flexible panel is adapted to flex outwardly in vessel use of a rise in internal pressure during heating of said liquid. The container of claim 11, wherein said amount of bending is in an inward direction relative to said plane. A container according to claim 11, characterized in that said container (1) comprises several of said flexible panels (3) spaced apart from each other along said longitudinal axis. Container according to claim 11, characterized in that the or each flexible panel (3) comprises one or more of said substantially central initiator zones (8), a pair of said flexure zones (5) spaced apart from said (8) towards the opposite longitudinal ends of said flexible panel (3). Container according to claim 1, characterized in that said initiating zone (8) is positioned closer to the center of the flexible panel (3), said flexible post (3) having a first and a second operating zone (5) extending longitudinally away from said initiating zone (8), said first flexing zone (5) extending towards a first end of said flexible panel (3) and said second (5) towards an opposing end of said flexure panel (3). The container of claim 18 adapted to contain liquid at an elevated temperature above room temperature, characterized in that said initiator (8) and / or said flexure zone (5) have an arc that varies in an extent radiating transversely along an axis of said container (1). A container according to claim 19, characterized in that it has a pair of substantially inflexible regions between which said initiating zone (8) and said flexure zones (5) extend, a flattened area (900 ' between said inflexible regions to provide a portion of the end of said initiator zone (8). 21. The method of claim 1, wherein the initiating means (8) and / or bending zone (5) provide two panel sections (3) which are at a vertex ΓΠ1. A container according to claim 1, characterized in that said flexure zone (5) is positioned towards a first longitudinal end of said flexible panel (3) and said initiator zone (8) is positioned in the direction at an opposite longitudinal end of said flexible panel (3). Container according to claim 1, characterized in that said initiating zone (8) projects away from said plane to a smaller extent than said bending zone (5). A container according to claim 1, characterized in that said initiating zone (8) is positioned closer towards a first longitudinal end of said flexible panel than said one of the flexure zone (5).