Seite - 52 - in Clean Water Using Solar and Wind - Outside the Power Grid

52 Clean Water Using Solar and Wind: Outside the Power Grid called the pump characteristics. The static and dynamic pressures are expressed as the head. Head is measured in metre liquid column and is proportional to the pressure that is created by the pump. Expressed differently: the head tells how high the pump can lift the water, given a certain pressure. The higher the flow rate the lower the head that can be produced by the pump. Figure 4.2 Typical pump characteristics or QH curves at different pump speeds (n). Q denotes the flow rate while H is the pressure, expressed in metres head. The relation between the head (H, expressed in m) and the pressure (p, expressed in Pa = N/m2) is H p g = ⋅ρ (4.1) Where ρ is the liquid density (kg/m3), and g the acceleration of gravity  (m/s2). The formula indicates that pumping at a pressure Downloaded from https://iwaponline.com/ebooks/book-pdf/520710/wio9781780409443.pdf by IWA Publishing user