The difference between single seated & double seated control valves

From the name we are able to clearly observe that the first is just one seat, and the other has a double seat, as suggested by its name may be the distinction between the valve seat. Double seat control valve has two seats may be the valve body, and also the single sitting down control valve has one seat within the valve body.
 
The pneumatic double seat control valve seat has lower and upper valve plugs, and also the fluid flows in the left side of body, goes through the valve seat and plug, and flows out of the right side. It may flow more medium than the usual single-sitting down control valve with similar nominal diameter, and also the flow capacity is elevated by about 20% to 25%. The forces functioning on the lower and upper plug can cancel one another out, therefore the imbalance pressure is small , the operating pressure difference is big.
 
1.The options from the single seat control valve: the leakage is small, the unbalanced pressure is big, and also the allowable pressure difference is smaller sized compared to double seat valve.
 
2. The characteristics of double seat control valve: large allowable pressure difference. It is almost always especially appropriate for applications with large flow rates, ruthless drops and enormous leakage.