The oval gear flow meter is a kind of volumetric measuring instrument and is mainly composed of meter shell, oval gear rotor and transmission parts. It is an instrument used for continuous or discontinuous metering and control of liquids in the pipeline. It has advantages of lager metering range, excellent accuracy, small pressure loss, high viscosity adaptability, capability of measuring high-temperature and high-viscosity liquids, convenient demarcation and simple installation. It is applicable to the calibration and metering of crude oil, chemical, chemical fiber, traffic, commerce, food, medicine and health, scientific research and military etc.