Seal assembly

A seal assembly for installation in an annular groove having an inner radial surface and an outer radial surface which are interconnected by an axial surface, the seal assembly comprising:

• a generally annular energizer element formed of an elastomeric material to provide a low pressure seal, the energizer element being generally Y-shaped in cross section, including a body portion and first and second leg portions,
• the body portion including a first axial surface, a first radial surface having one end engaging one end of the first axial surface, a first angled surface having one end engaging the other end of the first radial surface, a second radial surface having one end engaging the other end of the angled surface and a second axial outer surface having one end engaging the other end of the second radial surface,
• the first leg portion including a second generally angled surface having one end engaging the other end of the second axial surface, a third angled surface having one end engaging the other end of the second angled surface and a third radial surface having one end engaging the other end of the third angled surface,
• the second leg portion including a fourth generally angled surface having one end engaging the other end of the first axial surface, a fifth generally angled surface having one end engaging the other end of the fourth angled surface to form a sealing lip for engagement with an element to be sealed to define a low pressure sealing lip contact area of a first predetermined axial width, and a fourth radial surface having one end engaging the other end of the fifth angled surface,
• a generally U-shaped surface extends between the other ends of the third and fourth radial surfaces;
• and
• a generally annular heel bearing element formed of a generally rigid material to provide a high pressure seal, the heel bearing element being generally L-shaped in cross section, including a first axial surface, a first radial surface having one end engaging one end of the first axial surface, a second axial surface having one end engaging the other end of the first radial surface, a second radial surface having one end engaging the other end of the second axial surface, a third axial surface having one end engaging the other end of the second radial surface and an angled surface extending between the other ends of the first and third axial surfaces,
• the seal assembly being installed within the groove with the second axial surface and the second angled surface of the energizer element engaging the axial surface of the groove, with the second radial surface of the energizer element engaging a first portion of the outer radial surface of the groove, with the first radial surface of the heel bearing element engaging a second portion of the outer radial surface of the groove, with the angled surface of the heel bearing element engaging at least a portion of the fourth angled surface of the energizer element and with the first axial surface of the energizer element engaging at least a portion of the third axial surface of the heel bearing element, the second axial surface of the heel bearing element, the first angled surface of the energizer element and a third portion of the outer radial surface of the groove extending between the first and second portions thereof establishing a generally annular void, generally triangular in cross section,
• whereby upon the application of pressure below a first predetermined limit the sealing lip of the energizer element functions to perform primary sealing and upon the application of pressure at or above the predetermined pressure limit the energizer element is compressed and a portion of the energizer element moves into the annular void, drawing at least a portion of the sealing lip into the groove to reduce the axial width of the low pressure sealing lip contact area and applying radial pressure upon the heel bearing element so that the heel bearing element functions to perform the primary sealing function, the shape and location of the annular void being such that fluid within the annular void is forced out of the annular void and passes between the heel bearing element and the second portion of the outer radial surface of the groove.