Flow sensors are devices used to measure the flow rate or quantity of a gas or liquid in a system. They can be used to measure the rate of flow of a gas or liquid at a certain moment, or over a given period of time. Flow sensors can be used to detect leaks and changes in flow rate or to measure total flow. They come in many different types, such as electromagnetics, turbine, orifice plates, open-channel flow meters, pitot tubes, and Coriolis mass flow meters. Depending on the type of sensor, they use different methods to measure flow, such as measuring changes in pressure, temperature, or velocity.