Gate valves are commonly used in the mining, pulp and paper, and food handling industries, among others. As known in the art, the gate moves linearly, perpendicular to the direction of flow. Typically, gate valves are used in a fully opened or fully closed position, and generally considered not suitable for throttling applications. In order to seat properly when fully closed, the typical gate valve is shaped to occupy all or substantially all of the bore. While this provides for robust sealing, the shape of the gate also has its disadvantages.
In a fully open position, areas within the bonnet or guide of a typical gate valve, known in the art as the chest area, may be exposed to flowing materials. When used in higher flow applications, this flow can have a detrimental effect on the integrity of the valve. Materials can also get clogged within the chest area of the valve body and the guide. Even if the chest area could be suitably sealed off, the traditional shape of the gate may create flow characteristics not desirable for throttling applications.