Patent ID: 7328886

Claim:
A sheet having first, second, third and fourth edges along with first, second, third and fourth corners, for use with a heat exchange apparatus having a vertical axis, wherein the sheet generally lies in a plane that is generally parallel to the vertical axis, comprising: a first vertical rib that extends in a first direction generally parallel to the vertical axis along the sheet, substantially all the way between the first and second edges, wherein said first vertical rib protrudes in a second direction out of the plane; a second vertical rib that extends in the first direction along the sheet, substantially all the way between the first and second edges generally parallel to said first vertical rib, wherein said second vertical rib protrudes in the second direction out of the plane; a first horizontal rib that extends in a third direction along the sheet substantially all the way between the third and fourth edges, wherein said first horizontal rib protrudes in a fourth direction opposite said second direction, into the plane, wherein said first horizontal rib intersects said first vertical rib; a second horizontal rib that extends in the third direction along the sheet substantially all the way between the third and fourth edges generally parallel to said first horizontal rib, wherein said second horizontal rib protrudes in the fourth direction opposite said second direction, into the plane, wherein said second horizontal rib intersects said second vertical rib, a first foot located at the first corner, wherein said first foot comprises a first detent that protrudes in the second direction out of the plane, a second detent located adjacent said first detent, wherein said second detent protrudes in the fourth direction into the plane; a second foot located at the second corner, wherein said second foot comprises a third detent that protrudes in the second direction out of the plane, a fourth detent located adjacent said third detent, wherein said fourth detent protrudes in the fourth direction into the plane; a third foot located at the third corner, wherein said third foot comprises a fifth detent that protrudes in the second direction out of the plane, a sixth detent located adjacent said fifth detent, wherein said sixth detent protrudes in the fourth direction into the plane, and a fourth foot located at the fourth corner, wherein said fourth foot comprises a seventh detent that protrudes in the second direction out of the plane, a eighth detent located adjacent said seventh detent, wherein said eighth detent protrudes in the fourth direction into the plane, wherein said first and second vertical ribs and said first and second horizontal ribs form a boundary that surrounds at least one generally planar region.