Seal assembly with backup elements having coil springs positioned therein

Abstract

A seal assembly seals a cylindrical clearance space between first and second coaxial members, and is installed in a coaxial annular groove in the first member. The groove has a mouth, first and second side walls, and a base wall extending therebetween. An elastomeric annular seal element has in toroidal cross-section an axial leg and a radial leg. The axial leg extends axially along the groove base wall and includes axial end portions and a mid-portion therebetween. The radial leg extends radially from the mid-portion toward and through the groove mouth, and has opposing side surfaces and a contact surface therebetween. The contact surface is outside the groove and sealingly contacts the second member. A non-elastomeric annular back-up element is positioned adjacent one of the seal element radial leg side surfaces, and prevents extrusion of the seal element when pressure is applied adjacent the other side surface. The back-up element defines an annular channel that opens away from the adjacent seal clement side surface and toward the respective groove side wall. An annular biasing element is positioned in the channel and provides a radial force on the seal element and the back-up element toward the groove base wall, and prevents the back-up element from becoming displaced with respect to the seal element when pressure is applied to the seal assembly.