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Pneumatic Single Seat Valve Body
The most common control valve body style is Single Seated as shown in Figure 1, which has widely used in process control applications, particularly in sizes NPS (Nominal Pipe Size) 1 through NPS 4. Normal flow direction is most often flow-up through the seat ring.
Single Seated valves are available in various forms, such as globe, angle, bar stock, forged and split constructions.
Figure 1: Single Seat valve body
Since high pressure fluid is normally loading the entire area of the port, the unbalance force created must be considered in selecting actuators for Single Seated control valve bodies. Single Seated valves are known to work well in small sizes but it can often be used in 4 inch to 8 inch sizes with high thrust actuators.
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