Oval gear flow meters (also known as displacement flow meters, gear flow meters) are a type of positive displacement flow meters, and they are the most accurate type of flow meters. It uses a mechanical measuring element to continuously divide the fluid into a single known volume part, and measures the total flow volume according to the number of times that the metering chamber is filled and discharged with the volume part of the fluid successively and repeatedly. The oval gear flowmeter can be made of different materials (cast iron, cast steel, 304 stainless steel, 316 stainless steel), and is suitable for flow measurement in the chemical, petroleum, pharmaceutical, electric power, metallurgy and food industries.
The flow meter consists of a metering box and a pair of elliptical gears installed in the metering box, and the upper and lower cover plates form a sealed crescent-shaped cavity (due to the rotation of the gears, it is not absolutely sealed) as the calculation unit of a displacement. When the measured liquid enters the flowmeter through the pipeline, the pressure difference generated at the inlet and outlet pushes a pair of gears to continuously rotate, and the liquid measured by the crescent-shaped cavity is continuously transported to the outlet. The product of four times the secondary displacement is the total amount of the measured liquid flow rate (see figure for principle). The flowmeter is mainly composed of a housing, a counter, an elliptical gear, and a coupling (magnetic coupling and axial coupling).
Oval gear flow meters are also known as fixed displacement flow meters, or PD flow meters for short. They are a type of flow meters with higher accuracy, and are especially suitable for measuring the flow of high-viscosity media. The elliptical gear flowmeter uses a mechanical measuring element to continuously divide the fluid into a single known volume part, and measures the total volume of the fluid according to the number of times that the metering chamber fills and discharges the volume part of the fluid successively and repeatedly.