Couplings and Their Types...

Couplings and Their Types In all areas of a steel plant, there is a necessity for the reliability and high performance of machinery and equipment.  Couplings, serving as vital transmission parts, are no exception to meet higher and more stringent quality requirements needed for the steel plant’s equipment and machinery. In the simplest of terms, a coupling’s purpose is to transfer rotational movement from one shaft to another. Couplings are used to connect two shafts for torque transmission in varied applications. It may be to connect two units such as a motor and a generator or it may be to form a long line shaft by connecting shafts of standard lengths say 6 m to 8 m by couplings. In addition, couplings are capable of transmitting axial thrust loads between machines and any axial growth that may occur due to high temperature. Couplings may be rigid or they may provide flexibility and compensate for misalignment. They may also reduce shock loading and vibration. A wide variety of commercial shaft couplings are available ranging from a simple keyed coupling to one which requires a complex design procedure using gears or fluid drives etc. However there are two main types of couplings (Fig 1) which are (i) rigid couplings, and (ii) flexible couplings. Fig 1 Types of couplings Rigid couplings Rigid couplings are used for shafts having no misalignment. Since these couplings cannot absorb any misalignment the shafts to be connected by a rigid coupling must have good lateral and angular alignment. As compared with flexible couplings, rigid couplings have limited application. Rigid couplings do not have the ability to compensate for shaft misalignments and are therefore used where shafts are already positioned in precise lateral and angular alignment. Any misalignment between shafts will create high...