Abstract: This invention consists of a linearly operated gas vent assembly in which the dynamic range of gas flow is increased by use of a low drag actuator profile. The structure consists generally of a swivel vent module and a housing module, in which the swivel vent assembly regulates the volume flow of air and the housing module imparts spacial control over the direction of air flow. The swivel vent module comprises four sub-modules: a ball cylinder, an actuator cylinder, a valve disk, and an arrangement of hinging elements to rotate the disk. The ball cylinder is a cylindrical shell and constitutes an outer case of the swivel vent module. The outside surface of the ball cylinder is shaped as a segment of a sphere, with the inside surface being shaped as a straight cylinder and containing a circular seal grove. The actuator cylinder is a cylindrical shell with an outer diameter adapted to slidably conform to the inside of the ball cylinder.