A flow meter is an instrument that measures the velocity of a gas or liquid. It is used in medicine, chemical engineering and meteorology, just to provide a few examples. There are various forms of flow meters, including: air flow meters, mass flow meters, water flow meters, gas flow meters (or fuel flow meters) and peak flow meters.
The air flow meter is also known as an air consumption meter and is a device that measures the amount of air that flows through the tube. Its use is usually reserved for automobiles; it can measure the quality of the air in the engine, and it has an electronic control unit that calculates how much fuel needs to be injected into the intake manifold.
Another form of flow meter is the mass flow meter. This is also known as the inertial flow meter or the coriolis flow meter. This instrument measures the amount of fluid flowing through a team. The volumetric flow is metered proportionately to the mass flow rate when the density of the fluid is constant.
A water flow meter is a very accurate instrument for measuring flows in open channels and pipes that are partially filled. It makes use of velocity averaging to provide accurate flow measurements. It is chiefly used for conducting storm runoff studies, managing sewer flow, measuring flows in rivers and streams, and measuring the velocity of flow in ditches and canals.
Gas flow meters, also known as fuel flow meters, are instruments used in a stationary pumping fuel dispenser and in mobile vehicle instrumentation. They are used in cars, trucks and even ships and airplanes. They are usually constructed with principles such as turbine and positive displacement, but rapidly changing technology is paving the way for other measurements -- ultrasonic fuels, for example.
Finally, the peak flow meter is much like the other forms of flow meters. It is a portable device that detects the smallest decreases in air flow, and it is used primarily by people with asthma in order to keep their breathing under control.
Although each of these different flow meters performs its own functions, they generally fulfill the same purpose: to measure the rate at a liquid or gas is moving.