A valve assembly for controlling a flow of fluid includes a frame member and dual tubular valves arranged along the length of the frame member. The frame member includes fixed proximal and distal portions, and a rotatable intermediate portion. One valve is affixed between the proximal and intermediate portions, and the other valve is affixed between the intermediate and distal portions. The intermediate portion is selectively rotatable such that when one of the valves is in an open condition, the other valve is in a constricted condition.
