What are ball valves?
The ball valve is a rotational motion valve, which consists of globe-shaped disk that rotates to open and close the valve opening. The ball has a hole or port through the center so that flow will occur when the port is in line with the valve’s two ends. The ball conducts the same function as the globe valve’s disk.
Types of Ball valves:
Ball valves can be classified into 6 types based on the design and lubrication facility. These are the 6 types of ball valves:
Split-Body Ball Valve
Top-Entry Ball Valve
End-Entry Ball Valve
Three-Piece—Body Ball Valve
Double Trunnion Ball Valves
Lubricated or Nonlubricated Ball Valves
Split body Ball valve:
The split body design consists of a body with two parts, a cover, a ball, seat rings, a stem and other internals. A flange connection holds the two-part body together. One part of the body is smaller than the other.
The ball is inserted into the bigger portion of the body and a bolted connection assembles the lower portion of the body.
Top-Entry Ball Valve:
Top-entry ball valves provide access to internal valves for installation, disassembly, repair or maintenance by removing the valve cap cover. The valve is not required to be removed from the pipeline.
End- Entry Ball Valve:
Ball valves of the end-entry have a single-piece body. The ball is placed by an insert from one end. These valves have flange- or screwed-end connections. This design is commonly used for inexpensive small valves.
Three-Piece - Body Ball Valve:
The middle portion of the valve maintains all the valves indoors and the stem passes through a hole in the top. Bolts or studs and nuts hold two end caps together with the middle body. The end connections are part of the end caps and can be assembled, socket welded, threaded or flanged.
Double Trunnion Ball Valves:
The ball is equipped with two integral short-shaft extensions called the top and the bottom trunnions in this ball-valve model. These trunnions are mounted in bearings and rotate freely when the shaft is turned to open or close the valve when mounted in the top trunnion.
Lubricated or Nonlubricated Ball Valves:
Like other valves, bolted packing glands and O-ring seals are generally used to seal the stem.
A lubricant seal mechanism comparable to the one used in plug valves is accessible in some valve models. Lubrication seal systems valves are called lubricated ball valves, while others are called non-lubricated valves.