A continuous mass-spectrometric analysis of the evolved gases has been studied to achieve a novel on-line monitor for local overheating in hydrogen cooled turbine generators. The organic species evolved from the materials and the seal oil used in the generators were successfully detected employing a quadrupole mass-spectrometer. The overheating of the material and the oil contamination in the detector can be clearly discriminated by selecting mass numbers (channels) to detect out of 50 to 250 amu. More, each gas evolved from the material yields its individual mass spectrum, and hence the mass-spectrometric detection can define the material in which overheating spot exists by reference to the library of the decomposition gases. The mass-spectrometric equipment will realize a practical on-line (or continuous) monitor to detect local overheating in the operating turbine generators, combined with numerical data recognition system and the kinetic interpretation of the gas-evolution.

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Segregation becomes one of the big problems in industrial powder processes. This paper describes the influence of hopper shape on segregation. Change of the volume rate was evaluated when two size of particles (2 mm, 6 mm) were discharged from the hopper. In this study, effects of hopper diameter and slope angle on the segregation was investigated numerically. First, the influence of hopper inlet diameter was studied. As it decreased, segregation in last 10% flow became less prominent. Next, the influence of hopper slope was studied. As its slope was smaller, segregation was easy to occur. From observation of powder flow, funnel flow was occurred, and then large-sized particles moved to central area on the surface of powder bed by the rolling segregation. It was suggested that the difference of the vertical velocity between particles near the wall and that of center caused the rolling segregation.

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