The Research On Intelligent Averaging-velocity Tube Flowmeter

It is gradually known that averaging-velocity tube flowmeter has manyadvantages, such as simple structure, cheapness, relative high precision, convenientmaintenance, especially in low pressure loss and marked saving on energy sources. Sothe flowmeter has been applied widely and used as preferred meter especially in bigpipeline flow measurement.To take the further advantages of averaging-velocity tube flowmeter, andimprove its accuracy and intelligent extent, the research on intelligentaveraging-velocity tube flowmeter was proposed, including averaging-velocity tubeand intelligent processor unit with core of single chip microcomputer.Based on the system feature, the research content of this paper is divided twomain parts:1. To improve the measurement precision of averaging-velocity tube sensor: Thepaper analyzed the elementary structure and the measurement principle ofaveraging-velocity tube in theory and studied several main factors that affect theaveraging-velocity tube precision. The half-tube averaging-velocity tube was putforward. Its feasibility and high degree of accuracy have been proved by experimentdata.2. To develop high reliable intelligent processor unit: Intelligent processor unit is thesecond meter used for collecting sensor signal. According to the design demand ofsystem, all are conscientiously designed from whole system to special module. Andtry to adopt CMOS chip with high integration. This kind of design structure makes thecircuit more simple, the system more reliable and more stable. The paper basicallyanalyzed design thinking, working principle and measures anti-interference of allmodule's hardware and software in the system.The innovation of the paper is to design intelligent averaging-velocity tubeflowmeter and friendly interface: multi-menu design, good LCD display, particularhand-operation design, which make parameter setup both convenient and safe.The intelligent flowmeter can be used to measure accumulative flow rate ofvarious fluid, and the parameters of instantaneous flow rate, accumulative flow rate,temperature, pressure, density etc can be displayed at the same time.After system debugging, test has been completed in gas flow rate experimentaldevice in the process measurement and control laboratory in Tianjin University. Whenthe flow rate is low, the uncertainty is high. With the increment of flow rate, theuncertainty gets lower and lower. The test conclusion accords with systemrequirement.