DUAL ISOLATION VALVE WITH RECTANGULAR FLOW PASSAGEWAYS

摘要

A dual isolation valve comprises: a valve body with opposed inlet and outlet ports that defines an inner cavity; a first valve member; and a second valve member. The first valve member (preferably a plug) has a narrower first end and a wider second end and is rotatably mounted within the valve body cavity for rotation about a first axis of rotation substantially perpendicular to the flow axis defined by the inlet and outlet ports. The first valve member includes a substantially rectangular flow passage. The first end of the first valve member extends away from the second end along the first axis of rotation in a first direction, and the first valve member is rotatable between an open position, in which the flow passage is oriented to be generally aligned with and located on the flow axis to enable fluid entering the inlet port to pass through the flow passage, and a closed position, in which the flow passage is oriented to be generally perpendicular to the flow axis to prevent fluid entering the inlet port from passing through the flow passage. The second valve member also has a narrower first end and a wider second end and is rotatably mounted within the valve body cavity for rotation about a second axis of rotation substantially perpendicular to the flow axis. The first end of the second valve member extends away from the second end along the second axis of rotation in a second direction opposite the first direction (such that the first and second valve members are oriented in opposed directions). The second valve member, which also has a substantially rectangular flow passage, is rotatable between an open position, in which the flow passage is oriented to be generally aligned with and located on the flow axis to enable fluid exiting the first valve member to pass through the flow passage to the outlet port, and a closed position, in which the flow passage is oriented to be generally perpendicular to the flow axis to prevent fluid exiting the first valve member from passing through the flow passage to the outlet port. In this configuration, the flow of fluid through valve can be disturbed less than with prior art dual isolation valves while permitting extensive flow through the valve.