1) Quick Opening Flow
Maximum Change in Flow Rate at Low Valve Travels
When the Valve Plug nears the wide open position,
the change in flow rate approaches zero
Used primarily for on-off service
2) Linear Flow
Flow rate is directly proportional to the valve travel
Constant Pressure Drop
Valve gain will be the same at all flows
Used commonly for liquid level control
3) Equal Percentage Flow
- When the valve plug is near its seat, change in flow rate will
be small
- Generally used on pressure control
