Abstract: The valve comprises a casing which defines a receptacle having a main axis. The receptacle has a pair of opposed ports forming a flowway having an axis disposed at an acute angle to the main axis. A flow-control element is rotatably disposed within the receptacle. The element has an axis of rotation coaxial with the main axis. The body of the control element defines an axial open bore. The bore is in register with the flow ports at the fully-open position of the control element. A pair of elongated orifice slots extend circumferentially through the wall of the control element's body. At least one slot is defined by wall converging toward its trailing end. A chamber surrounds the walls of the axial bore in the control element's body. Silencing means in the body of the control element produce a silencing effect on the fluid flowing through the flowway only when the flowway is throttled by the orifice slots.