Mass flowmeter

Abstract

The invention relates to a mass flowmeter for highly precisely measuring mass flow directly. The mass flowmeter comprises two parallel U-shaped measuring tubes with an identical structure, a vibration exciter, two detectors, four fixed distance plates, two flanges, two end connecting tubes, two splitters, a middle connecting tube and a casing. The mass flowmeter provided by the invention has the advantages that the performance and the mechanical quality factor of a resonant sensor are effectively improved, the influence of a flow field is greatly reduced, the mass flowmeter has small flow resistance and low pressure loss and is simple to install and process, the measuring tubes have excellent dynamic balance properties, the mass flow of liquid with high viscosity and high impurity content can be measured, the application range of the Coriolis mass flowmeter is further enlarged, and the requirement of industrial development on the accuracy and the range of flow measurement is met. The mass flowmeter has great promotion effects for saving raw materials, lowering the production cost, reducing environmental pollution, increasing the profit rate and improving the product quality.

Description

technical field [0001] The invention relates to the field of testing and measuring instruments, in particular to a new U-shaped Coriolis mass flowmeter. Background technique [0002] Mass flow measurement technology is the focus of the development of national science and technology in the field of process control. In order to achieve high-accuracy and high-reliability measurement of various media under complex environmental conditions, Coriolis Mass Flowmeter (Coriolis Mass Flowmeter, referred to as CMF, also known as Coriolis mass flowmeter) has become one of the important development technologies in this field because of its superior performance, and it meets the major needs of the country. CMF can directly measure the mass flow of the fluid in the pipeline with high accuracy, and use the Coriolis effect generated when the fluid flows through the vibrating pipeline to affect the vibration phase or amplitude at both ends of the pipeline to measure the quality and stability ...

AI Technical Summary

Problems solved by technology

The pipe wall is thicker, the rigidity is small, and it is less affected by corrosion; its resonance frequency is low, generally 70-120Hz; the phase difference reflecting the mass flow rate is milliseconds, and the electronic signal is easier to process; but the elbow type is easy to accumulate gas and fluid residues cause additional errors, and the manufacturing process is more complicated than the straight tube type

[0006] Straight tube type CMF measuring tube, due to its high rigidity, high resonance frequency, and small amplitude, about 60 μm; due to its high frequency, it is quite different from the general mechanical vibration frequency in industry, so it is not easily disturbed by external vibration; Accumulated gas and residue, small size; in order to prevent the resonance frequency from being too high, the pipe wall is designed to be thin, about 1 / 4 to 1 / 2 of the elbow, so the wear resistance and corrosion resistance are poor

The phase difference reflected in the mass is on the order of microseconds, and the processing of electrical signals is difficult, which seriously limits the measurement range of CMF, and the sensitivity of this traditional vibrating straight tube CMF is low and affected by temperature fluctuations

The straight tube type or similar straight tube type CM F developed and applied at home and abroad, such as the published patent: Coriolis mass flow meter (patent application number is 00129058.4), is made into a bow shape bent in one direction, this structure Most of them are curved pipes, the flow rate is not stable, and the fluid is easy to generate adsorption and precipitation on the inner wall of the pipe; the installation and processing are complicated, and the dynamic balance characteristics are poor

[0007] At present, there are some restrictive factors in the developed CMF: for example, the overall performance of the CMF measuring tube design is poor, the installation of the pipeline is unstable, and the mechanical realization of the tube shape is difficult; the CMF is sensitive to external vibration interference; the CMF system cannot be used for Measuring low density media

When measuring gas-containing liquids, if the gas content is too large, the measurement accuracy will be affected; the measuring tube is affected by the design, processing and installation process, and its dynamic balance characteristics are poor, which directly affects the performance of the CMF and is irreversible

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