Pumps and their Types...

Pumps and their Types Pumps of different types and sizes are used in large numbers in a steel plant. They have got a very wide range of application in the steel plant and in many areas, pumps form critical piece of equipment for the process. A pump is a device that adds energy into the fluids (liquid or gases), or sometimes slurries. The energy can be expressed in two ways i.e. either an increase in pressure or an increase in flow. Pumps are used to move or raise fluids. They are not only very useful, but are excellent examples of hydrostatics. Pumps operate by some mechanism, and consume energy to perform mechanical work by moving the fluid. Pumps operate via many energy sources, including manual operation, electricity, engines, or wind power. They come in many sizes, from microscopic to very large industrial pumps. Pumps may be classified as positive displacement pumps and non-positive displacement pumps (Fig 1). Fig 1 Types of pumps Positive displacement pumps These pumps deliver a constant volume of fluid in a cycle. The discharge quantity per revolution is fixed in these pumps and they produce fluid flow proportional to their displacement and rotor speed. These pumps are used in most of the industrial fluid power applications. The output fluid flow is constant and is independent of the system pressure (load). The important advantage associated with these pumps is that the high-pressure and low-pressure areas (means input and output region) are separated and hence the fluid cannot leak back due to higher pressure at the outlets. These features make the positive displacement pump most suited and universally accepted for hydraulic systems. The important advantages of positive displacement pumps include capability to generate high pressures, high volumetric efficiency, high power to weight ratio, change in efficiency...