Single port valve bodies
This is the most common style and is simple in its construction. Various forms of this valve seat are available – angle, globe, forged, bar stock, and split constructions. The single port valves are used where the shut off requirements are stringent. In these china zonkin valves metal to metal seating surface or soft seating with PTFE or other material is used to make the seat. Most service requirements can be handled with these types of valves. Due to the fact that the high pressure fluid is loaded in the complete area of the port, there is an unbalanced force created and this should be kept in mind while choosing actuators for them.
Balanced plug cage style valve body
This is also a popular type of valve used for many purposes. In this only one seat ring is used and hence it can be considered to be single ported. This provides the advantage of a balanced valve plug which usually only double ported valves provide. With the cage style trim there is the benefit of valve plug guiding, seat ring retention, and flow characterization. Apart from the sliding piston ring type seal separating the wall from the upper portion of the valve plug the cage cylinder completely ensures that there is no leakage of the upstream high pressure fluid into the downstream system which is lower pressure.
High capacity cage guided valve bodies
These are mainly designed for noise applications like high pressure gas reducing stations where the velocity of gas is quite high especially at the outlet of the conventional valve bodies. There are oversized end connections incorporated in the design with a streamlined flow path which makes the trim maintenance easy with cage style constructions.
Ball Valve 