Valves are used in a wide array of industrial, medical and commercial applications. They are primarily used to regulate the flow of fluids, gases and semi-solid materials by operating certain hatches or passages. These valves are designed to provide tight shut-off and characterizable control. They possess a high range ability because of the design of the regulating element, without the complications any of side loads that are typical of butterfly or globe valves.
Ball valves are extremely efficient in regulating the flow of liquids. A ball valve in principle is a handle connected to a ball which is placed inside a valve. The ball has an aperture through which liquids can flow when the ball is in proper alignment with the valve. The ball has a hole or port through the middle of it so when the port is in line with both ends of the valve the flow of liquid will be allowed. When the ball valveis closed, the hole is then perpendicular to the ends of the valve and the flow of liquid is blocked. The handle position on the valve will allow you the valve's position. Three-way ball valves are also available which have a T-shaped hole through the middle of them. The flow of liquid can be directed to either one or the other or both sides or be closed off completely with this type of valve.
There are four main types of ball valves which are the: full port, standard port, reduced port and trunnion.
A full port ball valve consists of an oversized ball so that the hole in the ball is the same size as the pipeline. This results in lower friction loss and the flow of the liquid is unrestricted.
A standard port ball valve is generally less costly, but it has a smaller ball and a correspondingly smaller port. The flow through a standard port ball valve is one pipe size smaller than the valve's pipe size which results in slightly restricted liquid flow.
The flow through a reduced port ball valve is two pipe sizes smaller than the valve's pipe size which results in restricted flow of liquid. A trunnion ball valve has a mechanical means of anchoring the ball at both the top and the bottom. Ball valves are normally made from either metal, plastic or ceramics.
The balls that are used in valves need to be highly corrosion resistant in order to avoid wear and tear. Most ball valves are normally reinforced with nickel or chrome to give them a longer life. Recently some ball valves have become available with actuators that are pneumatically operated. Source: industrial101.com
