Abstract: An instrumental error compensating method has super precision measurement function, even in a condition having only micro temperature changes, by utilizing a computer which compensates for flow rate errors instantaneously and sends signals for indicating corrected values. Flowmeter (1) of the type having elliptical gears or roots type rotor has temperature sensor (5) mounted thereon and a rotation sensor (6) for indicating temperature and rotational speed of rotor. The signals from the sensors as fed to microcomputer (100). The errors can be caused by wear temperature changes, and viscosity chanter, for based on flow rate and temperature of the fluid detected by the sensors.

Abstract: A pair of elliptic gear wheels to be installed in a metering chamber casing of positive displacement type flow meters and have a modified gear wheel and the change of gear form of an effective gearing pressure angle of an involute gear form side of long radius and of an elimination of trapping phenomenon of cycloid gear form of short radius of wheels. This pair of gear wheels has super precision measuring functions and excellent repeatability, by utilizing a computer which compensates flow rate errors instantaneously and send signals for indicating corrected values. Meshing of the pair of wheels at a top of an involute gear form on a middle portion of a pitch circle can keep meshing of the pair of wheels and a cycloid gear form side of short radius eliminates trapping phenomenon.

Abstract: An instrumental error compensating device has super precision measurement functions, even in a condition having only microtemperature changes, by utilizing a computer which compensates for flowrate errors instantaneously and sends signals for indicating corrected values. Flowmeter (1) of the type having elliptical gears (4,4') has temperature sensor (5) mounted thereon and a rotation sensor (6, 71) for indicating temperature and rotational speed. The signals from the sensors are fed to a micro computer (100). The errors can be caused by wear temperature changes, and viscosity changer, for example, and are compensated for by the computer based on flow rate and temperature of the fluid detected by the sensors.

Abstract: An elliptic gear wheel or rotor having a predetermined pitch circle which includes longer and shorter radius and intermediary portions between said longer and shorter radius portions, the longer and shorter radius portions have teeth of a greater tooth pressure angle than that of teeth on the intermediary portion, and a transmission gear device including at least two identical elliptic rotors of the above type mounted in their respective support shafts in intermeshing relationship to each other.