CHAPTER 3 CALCULATION
3.1 calculation of centrifugal pump
In EDR(Electrodialysis reversal) the centrifugal pumps are used. The calculations for centrifugal pump is as under.
1)Centrifugal pump performance capacity(mass flow rate) can be calculated in the following way:
Q = b1•(π•D1-δ•Z)•c1 = b2•(π•D2-δ•Z)•c2
Q – centrifugal pump performance capacity, m3/s b1,2 – widths of impeller pass through diameters D1 and D2,m
D1,2 – inlet external diameter (1) and impeller external diameter(2), m δ –thickness of blades, m
Z – number of blades
C1,2 – radial components of absolute velocities at impeller inlet (1) and its outlet (2), m/s
2)General formula of head calculation (diameters of suction and discharge pipes are taken as equal):
H = (p2-p1)/(ρ•g)…show more content… Centrifugal pump use the centrifugal force to supply the water to one end to the other. Centrifugal pumps are used to transport fluids by the conversion of rotational kinetic energy to the hydrodynamic energy of the fluid flow. Fluid enters axially through eye of the casing, is caught up in the impeller blades, and is whirled tangentially and radially outward until it leaves through all circumferential parts of the impeller into the diffuser part of the casing. The fluid gains both velocity and pressure while passing through the impeller. The doughnut-shaped diffuser, or scroll, section of the casing decelerates the flow and further increases the pressure.
4.2) Flow control valve:
*A ball valve is a form of quarter-turn valve which uses a hollow, perforated and pivoting ball to control flow through it.
*It is open when the ball's hole is in line with the flow and closed when it is pivoted 90-degrees by the valve…show more content… *Valve bodies are made of metal, plastic, or metal with a ceramic; floating balls are often chrome plated for durability.
*One disadvantage of a ball valve is that they trap water in the center cavity while in the closed position. In the event of a freeze, the sides can crack due to expansion of ice forming.
body 2) seat 3) floating ball 4) lever handle 5) stem
4.3) Power supply:
In EDR the direct current are used for purification.
The normally supplied electric current is alternating current.
So the alternating current(AC) is convert to direct current(DC) by using rectifier. A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction. The process is known as rectification.
Rectifiers have many uses, but are often found serving as components of DC power supplies and high-voltage direct current power transmission systems. Rectification may serve in roles other than to generate direct current for use as a source of power. the output of the rectifier is smoothed by an electronic filter (usually a capacitor) to produce a steady