2. Faucets

2.1 Valve selection, notion of Kv and Cv

The size of a valve is often described by the nominal size of its end connection. But for most fluid systems, the allowable flow rate for a valve is a more important measure. The principles of flow calculation require that certain aspects of the flow path be known, including :

• 1.Size and shape of orifice and flow passage.

• 2.Internal diameter of pipe or tube.

• 3.Fluid characteristics, such as density and temperature.

• 4.Pressure drop between inlet and outlet.

It's easy to understand that a straight-through flow path, such as that of a ball valve (figure