What is a flow meter?

1. What is a flow meter?

A flow meter is an instrument that measures a mass or volumetric flow rate of a gas or liquid. You might have come across a variety of terms when referring to a flow meter, such as flow sensor, mass flow meter, mass flow controller, flow regulator etc.

The purpose of a this instrument basically is measuring the flow of gas or liquid between two points in a process. Sometimes controlling or regulating the flow is necessary. This is done by combining a flow meter with a valve, creating a flow controller. In this case, besides measuring a flow, you can also control it to change the flow rate. The output can help you understand your process better to make decisions regarding product quality, speed of process and cost reduction.

2. How does a flow meter work?

There are two basic types of fluid measurement – mass and volume flow measurement. The volumetric flow measurement is temperature and pressure dependent especially for gas and will be shown in units of volume such as ml/min or m3/h. When measuring mass flow, you see units of mass such as kg/h or g/min. Alternatively, because gas is compressible, it is more convenient to express mass flow as standardized volumes e.g. mls/min or m3n/h. Therefore, you can either choose for a mass flow meter or a volumetric flow meter for your application.