Basics of Pneumatics and Pneumatic Systems Nov14

Basics of Pneumatics and Pneumatic Systems...

Basics of Pneumatics and Pneumatic Systems Pneumatics has long since played an important role as a technology in the performance of mechanical work. It is also being used in the development of automation solutions.  Pneumatic systems are similar to hydraulic systems but in these systems compressed air is used in place of hydraulic fluid. A pneumatic system is a system that uses compressed air to transmit and control energy. Pneumatic systems are used extensively in various industries.  Most pneumatic systems rely on a constant supply of compressed air to make them work. This is provided by an air compressor. The compressor sucks in air from the atmosphere and stores it in a high pressure tank called a receiver. This compressed air is then supplied to the system through a series of pipes and valves. The word ‘Pneuma’ means air. Pneumatics is all about using compressed air to do the work. Compressed air is the air from the atmosphere which is reduced in volume by compression thus increasing its pressure. It is used as a working medium normally at a pressure of 6 kg/sq mm to 8 kg/sq mm. For using pneumatic systems, maximum force up to 50 kN can be developed. Actuation of the controls can be manual, pneumatic or electrical actuation. Compressed air is mainly used to do work by acting on a piston or vane. This energy is used in many areas of the steel industry. Advantages of pneumatic systems Pneumatic systems are widely used in different industries for the driving of automatic machines. Pneumatic systems have a lot of advantages. High effectiveness – There is an unlimited supply of air in the atmosphere to produce compressed air. Also there is the possibility of easy storage in large volumes. The use of...

Basics of Valves

Basics of Valves A valve is a mechanical device specially designed to control the fluid flow and pressure within a system or process. Valves are designed for either liquid or gaseous application. A valve carries out any of the following functions. Stopping and starting of flow of the fluid. Throttling the amount of fluid flow Controlling the fluid flow direction Regulating the downstream system or process pressure Relieving the over pressure in the system Regulating the temperature of process fluid Controlling the mixing of fluids Since there is diversity of the types of systems, fluids, and environments in which valves are to operate, valves have many designs and types which satisfy one or more of the identified functions. By nature of their design, function, and application, valves comes in a wide variety of styles, sizes, and pressure classes. A multitude of valve types and designs safely accommodate a wide variety of valve applications.  These days range of valves extends from simple water cocks to control valves equipped with microprocessors, which provide single loop control of the process. The most common types of valves in use today are gate, globe, plug, ball, needle, butterfly, check, pressure relief, diaphragm, pinch, and safety valves etc. Valves are manufactured from a number of materials which include carbon steel, alloy steel, stainless steel, iron, brass, bronze, aluminum, plastics and a number of special alloys. Valves can have threaded end connection, flanged end connection, welded connection, or other type of connection like union end connections in case of some plastic valves. Regardless of type, all valves have the basic components which include valve body, bonnet, trim (internal elements), actuators, and packing. These are described below. A valve along with its basic components is shown in Fig 1. Fig 1 A...