Disc valve for sampling erosive process streams

Claim 1

A four-port disc valve for sampling a high temperature erosive process stream, comprising: a rotatable disc defining first and second sampling cavities spaced 180° apart; first and second faceplates disposed respectively on each side of said rotatable disc; silicon carbide inserts being provided in each of said faceplates in contact with said rotatable disc; said first and second faceplates respectively defining first and second flow passageways spaced 180° apart and positioned to be alternatively in axial alignment with said first and second sampling cavities; said sampling cavities being provided with α silicon carbide liners comprised of hollow tubular liner segments separated within each of said sampling cavities by compressible gaskets which urge said linear segments against said silicon carbide inserts; means for passing at least part of said process stream through one of said first and second flow passages in said faceplates; means communicating with the other of said first and second passageways for recovering sample materials from said sampling cavities; and means for rotating said disc to transfer samples of said process stream from one of said flow passageways to the other.