Coriolis effect mass flowmeter

Abstract

A Coriolis effect mass flowmeter for measuring mass material flow in a conduit. Elements of the meter are clamped directly onto an existing pipe or other conduit without diversion of the flow. The meter comprises a driver, such as a magnetostrictive driver, to oscillate a section of pipe between two supports. The driver is mounted on the pipe section at or near an anti-node of the second harmonic mode of the natural frequency of the pipe section. A sensor, such as an accelerometer, is mounted onto the pipe section at the node point of the second harmonic mode of the natural frequency of the pipe section during zero flow, (zero flow node point). The second sensor measures the amplitude of displacement of the zero flow node point due to the Coriolis effect forces from the mass of the material flowing through the oscillating pipe. This measurement is indicative of the mass flow rate of the material flowing through the pipe. The meter is not dependent upon phase shift detection and is not susceptible to extraneous noise and does not require a complicated mounting. In one alternative embodiment, the meter is prefabricated on a section of pipe which can then be installed in a pipeline as an off the shelf item. In another alternative embodiment, a pair of sensors is affixed to different locations of the pipe section to generate phase or time separated signals. The signals are applied to processing circuitry that determines mass flow rate information from the phase or time separated signals.