A shuttle valve is a type of valve which allows fluid to flow through it from one of two sources. Generally a shuttle valve is used in pneumatic systems, although sometimes it will be found in hydraulic systems.

Structure and function

The basic structure of a shuttle valve is like a tube with three openings; one on each end, and one in the middle. A ball or other blocking valve element (the shuttle) moves freely within the tube. When pressure of a fluid is exerted through the opening at one end it pushes the shuttle towards the opposite end, closing it. This prevents the fluid from passing through that opening, but allows it to flow out through the middle opening. In this way two different sources can provide pressure to a device without the threat of back flow from one source to the other. In pneumatic logic a shuttle-valve works as an OR gate.

Applications

A shuttle valve has several applications including: