Valve stem assemblies

A valve stem, comprising:

• a straight hollow tube and a compression sleeve mounted to the hollow tube;
• wherein the hollow tube and compression sleeve are partially insertable through a container wall opening from an exterior side of the container wall through to an interior side of the container wall, and a mechanism accessible from the exterior side of the container wall to compress the compression sleeve against the interior side of the container wall;
• wherein the hollow tube is metal and has one external thread partially extending along a middle of its exterior surface and a flange at a distal end to retain a distal end of the compression sleeve while under compressive forces;
• the compression sleeve is made from a flexible and compressible material;
• wherein the compression sleeve while under compressive forces forms a void between an inner wall of the compression sleeve and hollow tube, wherein the compression sleeve expands against the container wall opening and against the interior side of the container wall;
• and
• wherein the mechanism accessible from the exterior side of the container wall to compress the compression sleeve against the interior side of the container wall comprises:
• at least one nut mounted to external threads on the middle of the hollow tube, whereby when the nut is rotated, the hollow tube is partially withdrawn from the container interior.