Installed Control Valve Flow Characteristics

Control Valve Flow Characteristic Curve showing the relationship between control valve capacity and range of motion of the valve stem of the valve which has a different design, Trim it. Indeed, by its very nature, valves typically have a non-linear behavior, but the design is different Trim enables Control Valve Flow Characteristic. In various ways as shown.

Inherent Control Valve Flow Characteristics.

The above was compiled. characteristics. Can be found often on% volume flow through the valve can be plotted versus the distance of movement of the valve stem on the condition that the pressure loss through the valve needs to be fixed, we refer to grap that the inherent flow characteristics. By the following graph.

Linear - the volume of flow will be greater when compared to the movement of the valve is in a straight line.
Equal percentage - the amount of flow will be greater when compared to the movement of the valve to the line exponentially.
% Change in the movement of the valve is equal to% change the value of Cv.
A modified parabolic characteristic. Centered approximately linear and equal%.
It has good control on the flow volume is less. And a linear behavior at higher flow.
Quick opening of the flow is changed while the valve is opened from the closed position, indicating that the valve has a high gain is not commonly used in control. It is only used for on-off, as in the sequential system is a batch or semi-continuous processes.
Hyperbolic.
Square Root.
Primarily used in control systems and control valves with flow characteristic curve is linear, equal-percentage, or modified-flow characteristics.

Installed Control Valve Flow Characteristics.

When the valves are installed in the piping system. Transmembrane pressure across the valve is not fixed, is proportional to the movement of the plug to draw a graph of the actual flow% compared with the opening of the valve. The resulting graph is called Installed Flow Characteristic.

In most cases, when the valve opens up a part of the flow in the pipe before it reaches the valve, which will result in the loss of pressure lose a lot of pressure to it. Since the resistance of the pipe it. In this case, it will keep the pressure before the valve P 1 decreases the pressure drop across the valve decreases, which results in movement of the graph and the curve that is Installed Flow Characteristic Curve by me. an example.

The curve is linear up to look like the quick opening.
curve will shift up to an equal% similar to a linear curve.