A vent assembly comprising: an aperture formed in a wall of a reservoir , wherein the reservoir defines an interior volume, and wherein the aperture is in fluid communication with the interior volume of the reservoir; a closure member retained on the wall of the reservoir proximate the aperture, the closure member configured for rotation about an axis extending through the wall of the reservoir when moving between a vented position and an unvented position, wherein the closure member comprises a sealing surface that closes the aperture when the closure member is in the unvented position, and wherein the sealing surface does not close the aperture when the closure member is in the vented position; a closure member retainer , wherein the closure member retainer is configured to retain the closure member on the wall of the reservoir when the closure member is in the vented position; and a cam surface configured to generate a compressive force on the closure member when the closure member is moved into the unvented position, wherein the compressive force forces the sealing surface of the closure member against the wall of the reservoir when the sealing surface is positioned over the aperture , wherein the closure member is mounted on a post extending from the wall of the reservoir , wherein the closure member is configured for rotation on the post ; and wherein the closure member retainer is located on the post and configured to retain the closure member on the post when the closure member is in the vented position, and further wherein the compressive force is generated between the closure member retainer and the cam surface when the sealing surface is positioned over the aperture . an aperture formed in a wall of a reservoir , wherein the reservoir defines an interior volume, and wherein the aperture is in fluid communication with the interior volume of the reservoir; a closure member retained on the wall of the reservoir proximate the aperture, the closure member configured for rotation about an axis extending through the wall of the reservoir when moving between a vented position and an unvented position, wherein the closure member comprises a sealing surface that closes the aperture when the closure member is in the unvented position, and wherein the sealing surface does not close the aperture when the closure member is in the vented position; a closure member retainer , wherein the closure member retainer is configured to retain the closure member on the wall of the reservoir when the closure member is in the vented position; and a cam surface configured to generate a compressive force on the closure member when the closure member is moved into the unvented position, wherein the compressive force forces the sealing surface of the closure member against the wall of the reservoir when the sealing surface is positioned over the aperture , wherein the closure member is mounted on a post extending from the wall of the reservoir , wherein the closure member is configured for rotation on the post ; and wherein the closure member retainer is located on the post and configured to retain the closure member on the post when the closure member is in the vented position, and further wherein the compressive force is generated between the closure member retainer and the cam surface when the sealing surface is positioned over the aperture . <EOS>