Twin positive and negative seal pipe fittings

A seal for coupling the ends of pipes together comprising:

• a sleeve having openings concentrically receiving an end of each pipe into one of said openings;
• a peripheral ridge formed in the sleeve in concentrically surmounting relation to each pipe received within said sleeve, said peripheral ridge having four walls with the walls being of substantially constant cross sectional area and wherein the first and second walls slope outwardly at an angle from the external surface of the pipe and extend toward each other, the third and fourth walls being connected at an angle respectively to said first and second walls and form a continuous curved connection therewith, said third and fourth walls extending toward each other and extending toward the external surface of the pipe and being connected in a continuous curved surface to each other thus forming an annular bead, said bead being in spaced relation to the pipe;
• said four walls thereby forming a single pressure chamber with the pressure chamber being partially partitioned into two sub-chambers by said annular bead extending toward and ending in a spaced relation to said pipe;
• an O-ring packing member disposed in each sub-chamber, the packing members contacting respectively the curved connection between the first and third walls and the curved connection between the second and fourth walls, and contacting the external surface of the pipe, the O-rings thus forming twin positive and negative seals with both O-rings actively sealing at the same time;
• and
• indentation means formed in the sleeve and in each pipe for securing the sleeve to the pipe.