16-07-2012, 03:42 PM
MANUFACTURNG OF EXTERNALLY WELDED IMPELLERS
MANUFACTURNG OF EXTERNALLY .doc (Size: 3.21 MB / Downloads: 89)
INTRODUCTION
Centrifugal compressor, which is vital equipment in many process industries, forms a major product. For manufacturing centrifugal compressors, very specialize impeller vane welding should be used. BHEL manufactures a complete range of centrifugal compressors for all major compression applications. They are in oils and gas production, gas transportation, refinery and petro chemical industries, fuel gas boosting and other similar processes. The record for centrifugal compressor applications have designed and manufactured the first high pressure compressor for ammonia and urea plants, the most powerful compressors for offshore applications and re-injection compressors with delivery pressures as high as 10000psi(700bar) is been done in India.
COMPRESSOR COMPONENTS
Casings: Depending on the compressor family the casings can be classified as horizontally split and vertically split. Horizontally-split casing consist of two half casings joined along the horizontal center-line. All connections such as suction and discharge nozzles, side stream nozzles and oil pipe are normally fitted to the lower half so that the upper half becomes an easily removable cover.
Horizontally-split casings consist of two half casings joined along the horizontal center-line. All connections such as suction and discharge nozzles, side stream nozzles (if any) and oil piping are normally fitted to the lower half so that the upper half becomes an easily removable cover. The casings may be cast or fabricated steel depending on the compressor duty, service temperatures, gas handled and compressor size.
IMPELLERS
IMPELLER is a main component in the centrifugal compressors. It is mounted on the rotating shaft of the centrifugal compressor. It consists of vanes between the two discs. When the fluid shaft through the impeller from the eye towards the circumference, the kinetic energy is imparted to the gas. When this gas is allowed to pass through the diffuser, the velocity drops due to the increasing cross sectional area of the diaphragm and thus the pressure of the gas increases. Hence the impeller a critical component in the working of a centrifugal compressor.