An oval gear flow sensor measures liquid movement by detecting the rotation of precision-machined gears inside a chamber. The positive displacement design supports repeatable measurements for liquids such as diesel, lubricating oils, solvents, and process chemicals. Depending on the model, available features include digital display, 4–20 mA output, RS485 Modbus communication, and pulse output. The appropriate configuration depends on viscosity, flow rate, and process conditions.