Rotary flow regulating valve and method

Claim 1

A rotary flow regulating valve comprising a valve member having a spherical sealing surface; a valve body with a conduit therethrough for operative communication with a fluid flow conduit, said valve body enclosing said valve member for defining therewith a circumferential flow path between said sealing surface and said valve body and a diametrical flow path through said valve member; cylindrical expansible bellows means mounted in said valve body and encircling said conduit therethrough and having a first end fixed stationarily relative to said valve body and a second end movable toward the valve member on expansion of said bellows means; circular seal means encircling said conduit through said valve body and interposed between said second end of said bellows means and said valve member for movement between a position withdrawn from said valve member and a position in sealing engagement therewith; pressurizing fluid means operatively communicating with said bellows means for controllably pressurizing said bellows means independently of pressure conditions within said conduit and thereby for controllably urging said second end thereof toward said valve member and for imposing hoop stress on said seal means upon sealing engagement thereof with said sealing surface; and means for mounting said valve member for rotation within said valve body between a flow blocking position in which said sealing surface is disposed for sealing engagement of said seal means therewith and a full flow position, rotation of said valve member to intermediate rotational positions dividing fluid flow between said circumferential and diametrical flow paths with the ratio of division between said paths being varied by rotation of said valve member to a desired rotational position so as to regulate fluid flow through said body while maintaining distribution of fluid flow over said sealing surface.