Patent ID: 7793940

Claim:
A heavy duty end face seal assembly, comprising, in combination: a pair of seal carrier portions having anti-rotation means thereon, whereby one of said seal carrier portions is rotatable and the other is held against rotation; and a pair of composite seal portions carried by said seal carrier portions, each of said composite seal portions being of a right circular cylindrical shape and each including: a ring-shaped support layer secured to said seal carrier, said ring-shaped support layer comprising a support layer material selected from the class consisting of tungsten carbide, silicon carbide and silicon nitride material and each having a thickness of from about 2 mm to about 10 mm, each of said ring-shaped support layer being in turn secured to one of said seal carrier portions by brazing or by an epoxy resin adhesive; and a ring-shaped contact end face layer fused to said ring-shaped support layer using temperature and pressure, wherein said ring-shaped support layer serves as a substrate, said ring-shaped contact end face layer being-lapped to a finish of at least three helium light bands, said ring-shaped contact end face layer being made of an ultrahard material selected from the class consisting of polycrystalline diamond compact, polycrystalline cubic boron nitride and natural diamond monocrystalline compact material; said diamond compact material or cubic boron nitride material having a thickness of from about 0.2 mm to about 8 mm, said two ring-shaped contact end face layers being in direct sealing contact with each other; wherein each of the composite seal portions is made by cutting out a center portion of a composite disk to thereby form the composite seal portion; and wherein the composite disk comprises a first disk of said ultrahard material that is fused to a second disk of said support layer material by placing said first and second disks in superimposed relation, compressing said superimposed disks under a force of at least 50,000 lbs and heating said superimposed disks to a temperature of at least 2,000° F., wherein the ring-shaped support layer has a circular exposed interior edge formed by cutting out said center portion of said composite disk; and wherein the ring-shaped contact end face layer has a circular exposed interior edge formed by cutting out said center portion of said composite disk.