Lip seal

Claim 1

A structure for making a fluidtight seal between a region of higher and of lower pressure comprising: a pair of bodies having a common axis; an abutment surface on each of said bodies, there being a direction of positive flow along the said surfaces; a ring groove in one of said abutment surfaces, the ring groove including a boundary having a bearing surface facing toward the direction of positive flow, a backing lip surface contiguous to the bearing surface and extending therefrom toward said direction of positive flow and to the intersection with said abutment surface so as to form a reentrant lip extending toward said direction, the tangent to the backing lip surface at said intersection forming an acute angle with the central axis which faces said direction of positive flow, and a relief surface extending between the bearing surface and the abutment surface; a sealing ring in said ring groove comprising a continuous resilient substantially noncompressible body having a sealing leg and a bearing leg, said legs being angularly spaced apart, but deflectible toward one another by forces exerted thereon, the bearing leg having a bearing surface and a backing surface in that order from the central axis, the backing and bearing surfaces having in their free and undistorted condition, a shape which respectively matches and conforms to that of the entire bearing and backing lip surfaces of said groove, the sealing leg projecting beyond the abutment surface of its respective body so as to engage and seal with the abutment surface of the other body when the abutment surfaces are brought together said backing surface of said seal having a shape which matches and conforms to that of the entire backing lip surface of said groove when said abutment surfaces are in engagement with each other, all of said surfaces being surfaces of revolution around said axis; and means holding said bodies together.