High purity corrosion resistant butterfly valve

A high purity, corrosion resistant butterfly valve, comprising:

• (a) a body having an inner surface and an outer surface, the body including a pair of body halves each having an inner face extending between the inner surface and the outer surface, the butterfly valve comprises no sealing element between the inner faces so as to enable the fluid media to pass between the inner faces to the outer surface to provide an external indication of leakage;
• (b) a liner secured to the inner surface of the body, the liner including an inner surface defining a fluid media passage;
• and
• (c) a disk member pivotally movable in the flow passage between open and closed positions, the disk member forming a direct fluid seal with the liner in the closed position;
• (d) wherein the liner is not a coating, and wherein the liner and the disk member are substantially chemically inert and substantially non-contaminating with respect to high purity, de-ionized water.

A high purity, corrosion resistant butterfly valve, comprising:

• (a) a body having an inner surface and an outer surface, the body including a pair of body halves each having an inner face extending between the inner surface and the outer surface, the butterfly valve comprises no sealing element between the inner faces to enable the fluid media to pass between the inner faces to the outer surface to provide an external indication of leakage;
• (b) a liner fitted to the inner surface of the body, the liner including an inner surface defining a fluid media passage, an outer surface, and a channel between the inner surface and the outer surface, the liner being composed of polytetrafluoroethylene;
• (c) a disk member mounted on a stem, the disk member being pivotally movable in the flow passage between open and closed positions, the disk member consisting essentially of a 1:1 alternating copolymer of ethylene and chlorotrifluoroethylene;
• and
• (d) first resilient biasing means disposed in the channel for resiliently biasing the inner surface of the liner into direct sealing engagement with the disk member in the closed position;
• wherein the liner is not a coating.