“Pumps”
A pump is basically a hydraulic machine which receives liquid at it's inlet nozzle at a certain pressure then raises this pressure to a desirable higher value and discharges the liquid from the outlet nozzle. Pump converts mechanical power into hydraulic energy. When a hydraulic pump operates, it performs two functions. First, its mechanical action creates a very low pressure at the pump inlet which allows atmospheric pressure to force liquid from the tank or storage vessel into the inlet line of the pump. Second, its mechanical action delivers this liquid to the pump outlet. A pump produces liquid movement or flow: not necessarily an increase of fluid speed across the Pump.
Classification of pumps: Pumps may be classified on the basis of applications, the material of their construction, the liquids they handle and their orientation in space. A more basic system of classification could be the principle by which energy added to the fluid.
Dynamic Pump: In dynamic Pump, during pumping action, tangential force is imparted which accelerates the fluid normally by rotation of impeller within casing.
Positive Displacement Pump: Pumps which use fixed volume cavities displaced using a mechanical force to move fluid through the system. These pumps differ based on whether the motion used to displace the chamber is reciprocating or rotary.
Major Parameter for Selection of Pumps: The following points are to be considered at the time of pump selection. Major Parameter for Selection of Pumps
Comparison Table – Centrifugal vs. Positive Displacement: Table below outlines some of the main differences between centrifugal pumps, reciprocating pumps and rotary pumps. Note that “centrifugal”, “reciprocating” and “rotary” pumps are all relatively broad categories. The table below provides a comparison of features between these pump categories that generally holds true. It is possible to build special pumps outside the upper bounds of the pressures and flow rates listed, but such pumps would be prohibitively expensive for most applications.
Comparision Table of Pumps:
