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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. The flowmeter preferably includes a housing or body having a cylindrical bore in which is mounted a turbine having multip

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. The flowmeter preferably includes a housing or body having a cylindrical bore in which is mounted a turbine having multiple vanes, and which preferably rotates transversely to the direction of fluid flow. The clearance between the bore and outer edge of the vanes is selected for minimum resistance to 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 source and a photodetector. Fiber optics may be used to locate the light source and photodetector at a location remote from the flowmeter for high temperature or intrinsically safe applications. Flow measurements are made by digitally measuring the time periods between successive input generated by detection of the rotating vanes of the turbine. The microprocessor-based controller compensates for nonlinearities between turbine rotation rate and the actual flow rates by applying correction factors in the form of range-dependent linear approximation values. A preferred method for operating such a flowmeter system is also disclosed.

대표청구항 ▼

An electronic flow-measuring system, having a flowmeter provided with a turbine, for accurately sensing fluid flow of a liquid over a wide range of flows including a low flow region wherein the turbine rotates at less than five revolutions per second, the system comprising: a flowmeter body having a

An electronic flow-measuring system, having a flowmeter provided with a turbine, for accurately sensing fluid flow of a liquid over a wide range of flows including a low flow region wherein the turbine rotates at less than five revolutions per second, the system comprising: a flowmeter body having at least one fluid passage therethrough; a turbine having a plurality of vanes, disposed at least partially within the passage, and rotatable about an axis in response to fluid flow impinging upon the vanes; sensing means mounted at least in part in the body for producing an electromagnetic input signal whose period is inversely proportional to the rate of rotation of the turbine by detecting movement of the vanes past a predetermined location; signal processing means for converting the input signal into a first numerical value proportional to the period of the input signal; digital processing means for producing from the first numerical value a second numerical value adjusted to compensate for a predetermined nonlinearity if any between the rate of rotation of the turbine and the rate of fluid flow through the body at least in a low flow region of operation of the flowmeter; means for providing an output value corresponding to at least one of the second numerical values, and wherein the passage through the flowmeter body is a substantially cylindrical bore at least in the vicinity of the turbine, the turbine is mounted such that its axis of rotation is concentric to the axis of the bore, and the clearance between the vanes of the turbine and the bore is sized to enable the turbine to rotate at substantially the lowest possible rate of fluid flow of the liquid.