Abstract: A hybrid butterfly valve has a stationary seat and a valve closure disk which may rotate together with an actuating shaft from the fully open position to a position wherein the disk is aligned with the seat, and thereafter may be moved linearly into sealing relationship with the seat. The disk is supported by brackets having an elongated slot through which the shaft extends, the brackets being adapted to move linearly relative to the shaft. Cams fastened to the shaft initiate a 90.degree. rotation of the disk from the fully open position to the position where the valve disk is aligned with the seat, and the cams act thereafter in conjunction with followers carried by the disk to move the disk and the brackets linearly.