Abstract: A conduit (106), with geometry designed to enhance pressure sensitivity, is vibrated at resonance in two modes along different cross-sectional axes (a, b). Measuring the change in the frequency ratio squared of the modes yields a substantially linear relationship to pressure that is substantially immune to other material properties and other environmental factors. Moments of inertia in different cross-sectional axes are related to pressure as a result of the elliptical or oral cross section of the conduit (106).

Abstract: Apparatus and methods for detecting and correcting various fault conditions in an operating Coriolis effect mass flowmeter. The apparatus of the present invention receives information from an operating Coriolis mass flowmeter and compares the information to threshold signatures representing various fault conditions. When a fault condition is detected, output signals are applied to inform an operator and to control the mass flow rate through the flowmeter to correct the fault condition. Specifically, the methods of the present invention detect the presence of a crack in the flow tubes and stop the flow of material to prevent release of the material through a cracked flow tubes. Other methods of the present invention detect the void fraction of material flowing through the flow tubes, compute a corrected actual mass flow rate, and control the mass flow rate through the flowmeter to compensate for the effects of the void fraction.

Abstract: A coriolis mass flow meter which includes a ferromagnetic drive mechanism and ferromagnetic velocity sensors is disclosed. The drive mechanism includes a drive coil; a ferromagnetic drive keeper affixed to a flow conduit of the meter so that the keeper it is partially disposed in the field from the drive coil; a magnet for orienting the ferromagnetic domains of the drive keeper; and means for applying a drive signal to the drive coil. The velocity sensor includes a sensor coil; a ferromagnetic sensor keeper affixed to the flow conduit so that the keeper it is partially disposed in the field drawn across the sensor coil; a magnet for orienting the ferromagnetic domains of the sensor keeper, disposed so that a portion of its magnetic field passes through the sensor coil; and means for detecting a current induced in the sensor coil by changes in the sensor keeper position. The drive mechanism oscillates the flow conduit in response to the variable magnetic field produced by the drive signal.

Abstract: A method of brazing corrosion resistant, nickel-based, thin-walled tubing which includes substantial proportions of nickel, chromium and molybdenum to a stainless steel base member using a filler metal, principally comprising gold as a major constituent and nickel as a minor constituent, in a vacuum furnace without introducing stress corrosion cracks in the brazed tubing and also avoiding carbon precipitation. The brazing is conducted at a temperature of at least about 1900.degree. F. (1038.degree. C.) for a sufficient period of time to allow any carbide precipitation formed during the heating to redissolve and also to permit full, uniform flow of the filler metal. The heated members are rapidly quenched in an inert atmosphere to a temperature at least sufficiently low to avoid carbon precipitation in the tubing.