Optical Alignment Of Turbomachinery

PaperPg. 8-12.Optical alignment is a technique which has proven its usefulness in original installation, repair and maintenance of turbomachinery. Optical alignment, sometimes referred to as optical tooling utilizes precision optical instruments, such as alignment telescopes, jig transits, precision sight levels, etc.. rather than mechanical tools to determine straightness, flatness and squareness. The heart of the technique is an instrument with built-in optical micrometers for measuring displacement from a precise and referenced line of sight. The micrometers are divided into increments of 0.001", and the accuracy obtained when taking readings on an optical scale (Fig. 21 is approximately ±0.001" at l feet to -+-0.002" at 50 feet._ Because of inherent advantages over other techniques, optical alignment has gained widespread acceptance in the aircraft industry, paper mills, shipyards, and of course, the industries associated with the use of reciprocating and turbomachinery. The alignment of high speed rotating equipment is one of the most troublesome problems in industry today. It has been observed that many of the vibration problems encountered on rotating equipment, was a direct result of misalignment. The nature of this equipment which includes a power source (electric motor, steam turbine or gas turbine 1, a compressor /compressors or large pump and possibly a gear operating at high rotational speed, requires accurate shaft to shaft alignment when at rated load and design temperatures