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...

Fundamental of valves and their types...

Fundamental of valves and their types  Valves are mechanical devices. They are basic elements with which the flow of fluids and pressure within a system can be regulated. They are mainly used to control the direction of fluid flow as well regulate the amount fluid flowing through a particular system or a process. They perform any of the following functions. Starting and stopping or isolating fluid flow. This corresponds to on and off functions. Controlling or varying (throttling) the amount of fluid flow by change of direction or restriction. This corresponds to volume functions. Checking the flow or controlling the direction of fluid flow and preventing backflow. This corresponds to directional functions. Regulating downstream system or process pressure Relieving component or piping over pressure There are many valve designs and types that satisfy one or more of the functions identified above. A multitude of valve types and designs safely accommodate a wide variety of industrial applications. Regardless of type, all valves have the following basic parts: the body, bonnet, trim (internal elements), actuator, and packing. Valves work by creating a partial or complete obstruction in the flow of fluids. The formation of obstruction can be formed manually or by injecting automatic elements in the system. A manual valve is generally controlled by handles, pedals or levers. An automatic valve is generally driven by pressure changes (pneumatic valves), although there can be other versions as well, where they are driven by electrical signals (solenoid valves). Automatic valves are more common nowadays, except for operations which require human judgement. The regulation is accomplished by the varying resistance that the valve introduces into the system as the valve is stroked. As the valve modulates to the closed position the system pressure drop shifts to the valve and...