Screw seal and lubrication

A screw assembly comprising:

• a screw shaft having a helical thread profile;
• and
• a nut for mounting around said screw shaft;
• the screw assembly further comprising a first seal and a second seal, wherein each of said first seal and said second seal independently comprises a seal, the seal comprising:
• a seal body having an inner surface for mounting onto and sealing against a screw shaft;
• an internal chamber formed within said seal body, wherein one or more openings are provided on said inner surface to allow lubricant material to transfer between said inner surface and said internal chamber;
• and one or more external ports provided on a radial surface and/or an outer surface of said seal body for transferring lubricant material into or out of said internal chamber of said seal body;
• wherein respective external ports (27A, 27B) of said first and second seals (26A, 26B) are aligned with respective passages extending through said screw assembly to provide a re-circulating path for re-circulating lubricant material within said screw assembly.