Pressure container with differential vacuum panels

Abstract

A plastic container ( 1 ) has a first set of flex panels ( 2 ) and a second set of flex panels ( 3 ) one set being adapted to react to pressure changes within the container to a different degree than the other set. This can be achieved by different curvature and/or size and/or different distance from a central longitudinal axis of the container. At least one of the panels has at least two different extents of curvature. In some embodiments one or more of the panels may be flat.

1 . A container for accommodating volume contraction within the container after being filled with a heated liquid, having a sidewall portion including four flex panels spaced apart around the circumference of a body portion, and arranged as a first pair of opposed panels and a second pair of opposed panels, at least one of said flex panels having at least two different extents of curvature wherein the panels can deform inwardly to accommodate vacuum pressure caused by volume contraction of the heated liquid and wherein the panels are formed so the first pair of panels deforms inwardly at a different rate than the second pair of panels. 
     
     
         2 . The container of  claim 1  wherein one said pair of panels has a different amount of outward curvature to the other said pair of panels. 
     
     
         3 . The container of  claim 1  wherein one said pair of panels is substantially flat. 
     
     
         4 . The container of  claim 1  wherein one said pair of panels is substantially concave. 
     
     
         5 . The container of  claim 1  wherein one said pair of panels has a variable outward curvature. 
     
     
         6 . The container of  claim 1  wherein one said pair of panels has a generally even outward radius of curvature, excluding any ribs or grip features on said panels. 
     
     
         7 . The container of  claim 6  wherein one said pair of panels has a variable outward projection. 
     
     
         8 . The container of  claim 7  wherein a substantially central section of said panels projects outward to a greater extent. 
     
     
         9 . The container of  claim 7  wherein a substantially central section of said panels projects outward to a lesser extent. 
     
     
         10 . A container substantially as herein described with reference to any of the embodiments of the invention and as shown in any one or more of the accompanying drawings. 
     
     
         11 . The container of  claim 1  wherein said at least two different extents of curvature comprise varying amounts of projection from a plane defined by a longitudinal axis of said at least one panel. 
     
     
         12 . The container of  claim 11  wherein a substantially constant arc of curvature is provided along said longitudinal axis of said at least one panel. 
     
     
         13 . The container of  claim 11  wherein a variable arc of curvature is provided along said longitudinal axis of said at least one panel.