Elliptical gear flowmeters, also known as displacement flowmeters, are high - accuracy flow measurement instruments. They operate based on the positive displacement principle.

The flowmeter consists of a measuring chamber and a pair of elliptical gears installed within it. When the measured liquid enters the flowmeter through the pipeline, the pressure difference between the inlet and outlet causes the elliptical gears to rotate continuously. As the gears rotate, the liquid in the initial moon - shaped cavity is continuously transported to the outlet. By measuring the number of rotations of the elliptical gear and multiplying it by four times the volume of each displacement, the total flow volume of the measured liquid can be obtained.

Elliptical gear flowmeters have several advantages. Firstly, they offer high measurement accuracy, a wide flow range, and good repeatability. Secondly, the spiral rotor rotates uniformly, with low vibration and a long service life. Thirdly, they are insensitive to changes in the viscosity of the measured liquid, making them especially suitable for measuring high - viscosity liquids. In addition, they feature a simple structure, small size, and light weight, and are easy to install, requiring no straight pipe section before the meter.

These flowmeters are widely used in various industrial fields, such as the petrochemical, water treatment, food and beverage, and pharmaceutical industries. In the petrochemical industry, they are used to measure the flow rate of liquids such as crude oil and refined oil. In the water treatment industry, they are used to measure the flow rate of tap water and wastewater. In the food and beverage industry, they are used to measure the flow rate of various liquid foods. In the pharmaceutical industry, they are used to measure the flow rate of pharmaceutical liquids.

However, elliptical gear flowmeters are not suitable for fluids containing solid particles, as the solid particles can jam the gears and prevent flow measurement. Additionally, if there is gas in the measured liquid medium, it can also cause measurement errors.