US Patent 8640768 Sintered polycrystalline diamond tubular members

In one aspect of the present invention, an external tubular member comprises an external outside surface and an external inside surface joined by an external wall thickness. The external wall thickness comprises external sintered polycrystalline diamond. An internal member comprises an internal outside surface and an internal width. The internal width comprises internal sintered polycrystalline diamond. The external inside surface is adjacent to the internal outside surface.