A duck beak valve and/or pumps/pump systems that use such a valve are disclosed. The valve may include a flexible tube having an inlet portion and an outlet portion and a spigot having a spigot inlet portion and a spigot outlet portion. The inlet portion of the flexible tube is sealed relative to the spigot. Inner surfaces of the flexible tube outlet portion downstream of the spigot outlet portion close together when the valve is closed. At least one reinforcement engages the flexible tube and is adapted to pivot at an inlet end so that an outlet end of the reinforcement moves toward and away from a centerline of the flexible tube. The reinforcement reinforces the flexible tube against an externally applied backpressure when the outlet end of the reinforcement is disposed toward the centerline and the valve is closed.
展开▼
