circumferential direction, it is possible to write Eq. (1.10) as: (1.13) Euler's pump equation Based on Eq.(1.13) Euler developed the head pressure equation created by the impeller see Fig.2.2 (1) (2) In Eq. (2) the sum of 4 front element number call static pressure, the sum of last 2 element number call velocity pressure look carefully on the Fig 2.2 and the detail equation. Ht theory head pressure ; g = between 9.78 and 9.82 m/s2 depending on latitude, conventional standard value of exactly 9.80665 m/s2 barycentric gravitational acceleration u2=r2.ω the peripheral circumferential velocity vector u1=r1.ω the inlet circumferential velocity vector ω=2π.n angular velocity w1 inlet relative velocity vector w2 outlet relative velocity vector c1 inlet absolute velocity vector c2 outlet absolute velocity vector Velocity Triangle The color triangle formed by velocity vector u,c,w called "velocity triangle". This rule was helpful to detail Eq.(1) become Eq.(2) and wide explained how the pump works. Fig 2.3 (a) shows triangle velocity of forward curved vanes impeller ; Fig 2.3 (b) shows triangle velocity of radial straight vanes impeller. It illustrates rather clearly energy added to the flow (shown in vector c) inversely change upon flow rate Q (shown in vector cm). Efficiency factor , where: is the mechanics input power required (W) is the fluid density (kg/m3) is the standard acceleration of gravity (9.80665 m/s2) is the energy Head added to the flow (m) is the flow rate (m3/s) is the efficiency of the pump plant as a decimal The head added by the pump () is a sum of the static lift, the head loss due to friction and any losses due to valves or pipe bends all expressed in metres of fluid. Power is more commonly expressed as kilowatts (103 W, kW) or horsepower. The value for the pump efficiency, , may be stated for the pump itself or as a combined efficiency of the pump and motor system. Vertical centrifugal pumps Vertical centrifugal pumps are also referred to as cantilever pumps. They utilize a unique shaft and bearing support configuration that allows the volute to hang in the sump while the bearings are outside the sump. This style of pump uses no stuffing box to seal the shaft but instead utilizes a "throttle bushing". A common application for this style of pump is in a parts washer. Froth pumps In the mineral industry, or in the extraction of oilsand,