About Lesson
Displacement pump
A. Positive displacement pump:
- It discharges the same volume of water regardless of the head against which they operate.
- Must be powered to meet the maximum load resulting from its discharge capacity and the greatest head under which it will operate.
a) Reciprocating pump:
- Mostly seen in homes and sometimes called the piston or displacement pump.
- Function by means of piston movement which displaces water into a cylinder.
- The capacity depends on the size of cylinder chamber and the length and speed of stroke.
B. Variable displacement pumps
- Main feature is the inverse discharge rate and the pressure head.
- As the pumping head increases, the rate of pumping decreases.
- Requires greatest input of power at a low head because of the increase in discharge as the pump head is reduced.