Ball Valve

The ball valve has a spherical plug as a closure member. Seal on ball valves is excellent, the ball contact circumferentially uniform the seat, which is usually made of soft materials. Ball valves are mostly used in shutoff applications. They are not recommended to be used in a partially open position for a long time under conditions of a high pressure drop across the valve, thus the soft seat could tend to flow through the orifice and block the valve movement. Depending on the type of body the ball valve can be more or less easily maintained. Drop pressure relative its hole size is low. The seat material resistance of the ball valve limits the working temperature and pressure of the valve. The seat is plastic or metal made. They are used in steam, water, oil, gas, air, corrosive fluids, and can also handle slurries and dusty dry fluids. Abrasive and fibrous materials can damage the seats and the ball surface. Types of ball valve: -Float ball valve: the ball is held on two seat rings. -Trunnion ball valve: the ball is supported on its vertical rotation axis by a trunnion. The trunnion absorbs the pressure from the flow, therefore the contact between the ball and the seat is not excessively stressed and the operating torque can remain low. This design is recommend for big diameters and high pressure