Valve stem assemblies

1. 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to external threads on the middle of the hollow tube, whereby when the nut is rotated, the hollow tube is partially withdrawn from the container interior.

2. The valve stem of claim 1 , wherein the external threads have a stop at an interior end configured to stop the rotation of the nut when the extraction of the hollow tube reaches a predetermined position, wherein said stop is in a predetermined position which is reached before a fully clamped position against the container interior wall.

3. The valve stem of claim 1 , wherein the compression sleeve has an interior portion diameter at least 3/32″ greater than the container wall opening.

4. The valve stem of claim 3 , wherein the compression sleeve has an interior portion diameter having the greatest diameter to allow insertion through the container wall opening with 20 pounds of force.

5. The valve stem of claim 1 , wherein the hollow tube maintains a constant external diameter along its length.

6. The valve stem of claim 1 , wherein mechanism accessible from the exterior side of the container wall to compress the compression sleeve against the interior side of the container wall is a wingnut.

7. The valve stem of claim 1 , wherein the void of the compressive sleeve under a compressive force allows the compressive sleeve to circumferentially fold midway along its length to expand in diameter against the interior side of the container wall to double its thickness.

8. A valve stem, consisting of:

a straight hollow tube and a compression sleeve mounted to the hollow tube;

a valve core mounted with an airtight seal within 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, at least one nut mounted to the external thread on the hollow tube, whereby when the nut is rotated, the hollow tube is partially withdrawn from the container interior;

the compression sleeve is made from a flexible and compressible material; and

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.