Gate valve with lubricated secondary seal

A gate valve comprising:

• a first and second opposing housing members each having coaxial through passages, each of said housing members defining a transverse gate chamber when said housing members are joined together;
• a gate disposed within said transverse gate chamber and slidable therein from an open position in which the gate does not block fluid flow through the passages, and a closed position in which the gate is interposed between the passages;
• a first annular primary sealing sleeve disposed within said first housing member;
• a second annular primary sealing sleeve disposed within said second housing member, each of said first and second annular primary sealing sleeves adapted to sealingly engage each other under compression in the open position of the valve, and with the gate when the valve is closed and wherein the first and second annular primary sealing sleeves are each in the form of an axially deformable annular body of elastomeric material;
• a secondary sealing member aligned with said gate chamber and secured between said housing members above the first and second annular primary sealing sleeves, said secondary sealing member further having an peripheral wall adapted to sealingly engage the gate, said secondary sealing member having an aperture extending therethrough;
• an inlet channel disposed through at least one of said first or second housing members and aligned with said aperture of said secondary sealing member, said inlet channel being configured to provide lubricating fluid through said aperture of said secondary sealing member to said gate;
• and
• a dam at least partially surrounding an opening to said aperture, said dam extending outward from said peripheral wall and disposed between at least one of said first or second housings and said secondary sealing member, said dam having a lower portion angled away from said peripheral wall.