Pumps are devices used to transfer fluids mechanically and are classified into three major groups depending on the system used to transport the fluids. Fluids transported by pumps are gases and liquids. It is also worth noting that pumps are of different sizes and operate through various energy sources such as electricity and manual operation (Girdhar, 2004). Pumps are also used in many areas including aquarium and pond filtering, oil pumping and in biochemical processes.
Types of Pumps
Pumps are categorized into various groups depending on their method of displacement which includes positive displacement, impulse, velocity, gravity, steam and valveless pumps.
These pumps help in transferring fluids in both biomedical and engineering systems and it does not have valves present to regulate direction of flow. They may be used in aiding blood circulation and in microfluidics where they are used in pumping sensitive bio fluids.
These are pumps that use syphoning system by using downhill flow in drawing water from far underground in raised places to users in lower regions.
These are historical pumps which are powered by steam engine as well as pistonless pumps. Although these kinds of pumps are not very efficient, they are really cost effective.
These types of pumps involve addition of kinetic energy to the fluid in order to enhance speed of the fluid flow. They are further categorized into educator jet pump, mixed flow pump, axial flow pump, radial flow pumps, and centrifugal pumps depending on the way the velocity gain is achieved. Velocity pumps have continuous energy and are also characterized with conversion of added energy to increase velocity as well as conversion of increased velocity to an increase in pressure (Nesbitt, 2006).
These are types of pumps that use pressure created by gas or gas is trapped in the liquid especially water which creates pressure that pushes part of the liquid upwards. They include hydraulic ram pumps which are powered by hydropower, pulser pumps powered by kinetic energy and airlift pumps powered by air inserted into pipe (Nesbitt, 2006).
Positive displacement pumps
This type of pump transfers fluids by trapping a fixed amount and driving the confined amount into the release pipe. Others use mounting cavity on the suction part as well as a decreasing opening on the discharge side. It involves circle of operations where fluid moves into the pump cavity while the opening on the suction enlarges before the fluid flows out of the discharge while the opening collapses at a constant volume (American Institute of Chemical Engineers, 2007). This type of pump is very effective compared to other pumps because it produces similar flow at a given speed regardless of discharge pressure.
However, any increase in internal leakage amid high pressure may hinder the rate of low. Positive displacement pumps are further classified into various groups depending on the mechanism used in transferring the fluids. The classifications include rotary type positive displacement, reciprocating type positive displacement and linear type positive displacement pumps (American Institute of Chemical Engineers, 2007).
Pumps are generally very important devices particularly in the field of mechanical engineering. Pumps play major role in making work easier just like any other machine and further guarantee efficient and perfect results (Srinivasan, 2008). Perhaps life could have not been that easy in almost every field without discovery of pumps. Pumps have undeniably helped every person apart from the engineers and any further invention of more efficient pumps may add great value to the field of mechanical engineering.
American Institute of Chemical Engineers. (2007). Positive displacement pumps: A guide to performance evaluation. Hoboken, NJ: John Wiley & Sons.
Girdhar, P. (2004). Practical Centrifugal Pumps. Burlington: Elsevier.
Nesbitt, B. (2006). Handbook of pumps and pumping. Oxford: Elsevier in association with Roles & Associates.
Srinivasan, K. M. (2008). Rotodynamic pumps: (centrifugal and axial). New Delhi: New Age International (P) Ltd., Publishers.