Interference compression seal

Claim 1

An interference compression seal assembly comprising: first and second relatively displaceable machine parts; a delta-shaped annular seal of deformable material having memory, said delta-shaped seal comprising three surfaces only, a base surface to engage substantially all of the base of a U-shaped groove in the first machine part and two convergent diagonal side surfaces merging at an apex, said seal further comprising three corners, one corner being disposed at the intersection of each two surfaces, two of the seal corners to be respectively disposed in the base corners and the third seal corner comprising the apex to deformingly engage the second machine part; two generally triangularly shaped annular anti-extrusion rings having three major surfaces only and comprising hard rigid synthetic resinous material one of each of said ring surfaces being diagonally oriented between the other ring surfaces, the diagonal surface of the two rings respectively contiguously engaging substantially the entire length of the two diagonal surfaces of the delta-shaped seal, one of the other surfaces of each ring respectively engaging the opposed side walls of the groove and, the second of the other surfaces of each ring along their full length respectively engaging a common surface of a second machine part, the anti-extrusion rings being spaced from the base of the grooves and transmitting force to said groove base solely through the diagonal side surfaces of the seal, the anti-extrusion rings constricting and compressing the delta-shaped seal inwardly and toward the second machine part when so placed in said groove, each of the two anti-extrusion rings being separate one from the other at said apex seal corner and each presenting at said second other ring surface an annular circumferential wear surface, to engage said common surface of the second machine part which experiences relative motion in respect to said first machine part, the one other surface of each anti-extrusion ring comprising a radial surface, to contact the adjacent side wall of the groove.