Definition of linear and equal percent characteristic? float valves for water tanks

big block chevy valve covers

b16 valve covers

small block chevy valve covers

The most common features are shown in the figure above.The percentage of flow through the valve corresponds to the stem position.These curves are based on a constant pressure drop across the valve and are known as the inherent flow characteristics.

  • Equal percentage – flow capacity increases exponentially with valve trim travel. Equal increments of valve travel produce equal percentage changes in the existing Cv.
  • Linear – flow capacity increases linearly with valve travel.

Linear Characteristics:
• Used in liquid level or flow loops.
• Used in systems where the pressure drop across the valve is expected to remain fairly constant.
• Used when the pressure drop across the valve is a large proportion of the total pressure drop.

Equal Percentage Characteristics:
• Used in processes where large changes in pressure drop are expected.
• Used in processes where a small percentage of the total pressure drop is permitted by the valve.
• Used in temperature and pressure control loops.

Flow Characteristics of control valve
Flow Characteristics of control valve