CENTRIFUGAL PUMP SELECTION 1

At the time of the selection of centrifugal pumps, there are some very important things we have to consider, among other things:
1 CAPACITY

Expressed in the contents per unit of time. For example: m3 / h, m3 / s, l / sec, USGPM and so on. What is meant by the capacity of a pump is the pump's ability to drain / remove some fluid / fluid in units of capacity.
Leakage of fluid / fluid on the shaft seal or packing behind the water pump is not counted as capacity.

2 TOTAL HEAD / PRESSURE

Total head in the state in units of distance. For example: meters, feet and other-judgments. The pressure is expressed in units of pressure. For example: kg / cm2, bars, and others.
Total head and pressure is very important and related to each other and pump selection can be described as follows:
Head of a pump is mechanical energy used and passed on to the media in the handle, which is associated with heavy media, expressed in units of length. This head is independent of the density of the media, in other words a centrifugal pump can cause the same head for the type of fluid. But heavy media type will cause pressure on the pump.
The total head of a system (Ha) can be described as follows (see Figure 1 and Figure 2):




Hgeo: Head static
Static head is the height difference on the suction surface of the liquid with the press. If the pipe is above the surface of the liquid hit the Hgeo measured from the center line of the pipe.

Hsgeo: Head suction static
Static suction head is the height difference on the suction surface of the liquid line of the axis of the pump shaft premises.

Hzgeo: Head press static
Head press is static height differences on the surface of the liquid to the suction line of the pump shaft axis.

Pa: Pressure in the tank covered in the press

Pe: Pressure in a closed tank on the suction

Va: The flow velocity in the tank press

Ve: flow rate at the suction tank

EHV: The sum of all the pressure head loss in the system (pipe friction, friction valves, fittings danlain other on the suction and famil press).

p: density

g: the gravitational constant = 9.81 meters / sec2.

Thus the system head (ha) =


In practice the speed difference on the suction tank dantangki the press ignored so for the tank system tertutp be =

And to open the tank be =

3 TYPES, DATA LIQUID

And the data type of fluid is necessary in determining the selection of the pump. This is because each has a specific gravity of liquid different to be directly related to the power requirements of the first mover. In addition to the above, the kit also roasted must determine the appropriate material from the pump to the fluid being pumped, especially for liquids which are corrosive. The pumped fluid also has a different viscosity that will affect the pump curve. The higher the viscosity of a fluid (liquid viscous / viscous liquid? Eating will result in:

a. Pump capacity decreases
b. The total pump head decreases
c. Effesiensi pump decreases
d. Power needed rises

4 EARLY MOVER

Basically, the pump requires a first mover to move it / operate. In the selection of the first mover of the pump, the local conditions and the availability of energy sources strongly influence, in other words if there is a local power source and is not allowed to be held electrical source is not possible then we choose the electric motor as a first mover. For example, amid a vast estate then we can choose the diesel engine as a first mover.

a. Electric Motors


b. Diesel
Rotation speed that is often used is between: 580 - 3500 rpm.

c. turbine
Rotation speed that is often used is ranged between: 1750 - 8000 rpm.

Changes in the speed of rotation at the first mover will affect the pump curves. If the value of capacity (Q1), the total head (H1) and power (P1) has been known in the rotation speed (n1), then the new value for the round = n2 is as follows:

Power should be available by the first mover should suffice / greater than the power needed by the pump.
Power is needed by the pump as follows: