Measurement and Control in a Large Steam Turbine-Generator Department

Rapidly rising steam temperatures and pressures in addition to new design techniques have vastly increased both the quantity and quality of x-ray and ultrasonic testing required. Consequently, the development pressers, particularly in ultrasonics, which in its modern fore is of postwar birth, has been heavy. Some of the techniques, equipment and circuitry of present day inspection are described and the characteristics and operation of ultrasonic transducers rooted. Sodium iodide, the linear accelerator, and industrial television have brought the promise of mechaniztion to the examination of large castings, while the promulgation of acceptance standards and the use of ABC scan representation and recording gives equal promise of speeding up the inspection and quality control of forgings. Preliminary experiments and electronic design work towards these objectives are described. An interesting development is the use of ultrasonics in nozzle-area determination, wallthickness measurements on large castings, and liquid-level indication. Possibilities exist for automatic control of machining operations and liquid-level control. Distances and cross sections can be checked with accuracies of 0.1%. As a control device, the feedback nature of the system will tend to suppress dependence on machine or template accuracies.