| 摘要 |
An electronic flowmeter system including a turbine flowmeter and a digital controller for making highly accurate flow measurements over a wide range of fluid flows and pressures is disclosed. The flowmeter preferably includes a body having a cylindrical bore in which is mounted a turbine having multiple vanes which rotate transversely to the direction of fluid flow. The clearance between the bore and vanes is selected for minimum resistance to fluid flow at extremely low flow rates. Rotation of the turbine vanes is detected by use of a proximity sensor or an optical sensor employing an artificial light and a photodetector. Flow measurements are made by digitally measuring the time periods between successive input pulses generated by detection of the rotating vanes of the turbine. For high temperature or intrinsically safe applications, the optical sensor is used with a fiber optic cable so that the light source and photodetector can be located remotely from the flowmeter. For high pressure applications and applications involving flow measurements of chemically active fluids, a sensor housing including a stainless steel casing and a protective glass window at one end of the centrally-located hole passing through the casing is used.
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