Flow meters (flowmeters) and flow sensors are devices used for measuring the flow rate or quantity of a moving fluid or gas

Air velocity flow sensors measure air velocity or volume flow using insertion probes or capture hoods

Open channel flow sensors measure fluid flow through open channels

Gas flow meters are used for measuring the flow or quantity of a moving gas in an enclosed pipe or passage

Liquid flow meters are used for measuring the flow or quantity of a moving fluid

Solids flow meters measure the flow rate of bulk solids, powders, grain, etc

Gas flow switches and liquid flow switches, velocity, are used to measure the flow or quantity of a moving fluid in terms of velocity, such as feet per minute