Error analyses of filling control systems for liquid amount-given
It is of instructive significance to systematically analyze the factors that influence the precision of filling control systems for liquid amount-given. The sources of additional errors of volumetric flowmeter and Coriolis mass flowmeter were analyzed in the paper. The factors that influence the filling overshoot and lead to overshoot error were discussed in particular. Then the general system error was expressed and the main approaches to improving the filling precision were summarized. It is indicated that the filling precision of system is mainly decided by the precision of flowmeter and other instruments such as thermometer and manometer on condition that the valve is shut off in advance under low instantaneous flowrate. The influence of overshoot error on the filling precision of system is not remarkable.
The identification of external factors which influence the calibration of Coriolis massflow meters
Abstract It has been suggested that, by monitoring the sensor signals and the meter drive signal, it may be possible to create a Coriolis meter which can identify the presence of a variety of external disturbances and can give a warning and/or make a correction to the meter output in order to maintain accuracy. This paper presents the findings from an investigation of the response of commercially available Coriolis meters to such disturbances. The results of this program of tests are reported and the implications of these results on the practicality of the creation of an ‘intelligent’ meter are discussed.
Microstructure of the solder-casting zone in bridges of dental gold alloys.
The composition and structure were studied in the cast and in the solder of bridges which had failed clinically. Both materials were gold alloys but with different contents of Pt, Ag and Zn. The metallographic investigation revealed defects mostly in the solder, situated in the subsurface layer. SEM studied of the fracture surface revealed large porosites and a structure of dense parallel lines--striations--, indicating that the material had failed from fatigue. The materials in the fractured bridges were identified by micro-probe measurements. It was stated that cast material and solder material used together, were of different composition.