Basics of Hydraulics and Hydraulic Systems Nov07

Basics of Hydraulics and Hydraulic Systems...

Basics of Hydraulics and Hydraulic Systems Hydraulics is the generation of forces and motion using hydraulic fluids which represents the medium for the transmission of power. Hydraulic systems are extremely important for the operation of heavy equipments. The word ‘hydraulics’ is based on the Greek word for water and originally meant the study of the physical behaviour of water at rest and in motion. Today, the meaning has been expanded to include the physical behaviour of all liquids, including hydraulic fluids. Hydraulic systems are not new to the industry. They have provided a means for the operation of many types of industrial equipments. As the industrial equipments have become more sophisticated, newer systems with hydraulic power are being developed. Hydraulic systems are used in modern production plants and manufacturing installations and they play a major role in steel industry, mining, construction and materials handling equipment. Hydraulic systems are used to operate implements to lift, push and move materials. Wide range of applications of hydraulic systems in the industry has only started since 1950s. Since then, this form of power has become standard to the operation of industrial equipments. Today hydraulic systems hold a very important place in modern automation technology. There are many reasons. Some of these are that hydraulic systems are versatile, efficient and simple for the transmission of power. Transmission of power is the job of the hydraulic system, as it changes power from one form to another. In hydraulic systems, forces that are applied by the fluid are transmitted to a mechanical mechanism. To understand how hydraulic systems operate, it is necessary to understand the principles of hydraulics. Hydraulics is the study of liquids in motion and pressure in pipes and cylinders. The science of hydraulics can be divided into two...

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...