A flow meter, as the name suggests, measure the flow rate or volume of a liquid or gas flowing through a pipeline or other conduit. This meter comes in different types, designs, and sizes, but every meter work by detecting and measuring the velocity or pressure of the fluid passing through it. Ultrasonic flow meter measures the speed of sound waves in a fluid to calculate the flow rate. Gas turbine flow meter measures the rotational speed of a turbine rotor, which is proportional to the flow rate. There are also mechanical flow meter, electromagnetic flowmeter and pressure differential meter in this range. Flow meters are widely used in many industries, such as oil and gas, chemical, pharmaceutical, food and beverage, and water and wastewater treatment.