Flow meters are meant to measure the flow rate of liquids or gas as they travel. Companies in oil, gas, water, and other necessary materials for the developed world use flow meters to ensure that the materials get to their destination safely and efficiently. Flow meters can be categorized into several different aspects such as way of measurement, material they are measuring, and accuracy.
Gases and Liquids
Gases are measured by flow meters that consist of one or two tubes that vibrate as gas passes through them creating the Coriolis effect. This is done to measure the volume flow, mass flow, standard flow and density. These flow meters are also able to measure the temperature in order to decide if the gas flowing is doing so at a safe and effective rate. Flow meters measure net oil measurements through density determination. This way they can avoid errors from possible air bubbles in the tube and have more accurate and dependable measurements.
Liquid flow meters pass through a magnetic field and are induced with electricity. The voltage that the liquid is induced is proportional to the flow rate. This can only be used for conducted fluids, however. Other liquids must be measured by pressure.
Mechanical Flow Meters
These flow meters are simple and have been used for many years. You basically compare the time it takes for the liquid to fill the container and the inverse relationship is the flow rate. On a large scale this is done with pistons and gears. While these meters have been used for quite some time they are not as accurate or precise as modern flow meters.
These flow meters measure the speed at which the rotors rotate after fluid has been introduced into the rotors of the helix. This flow meter can be used on a smaller scale. Once upgraded it can become overwhelmed and less accurate.
A current meter measures hydroelectric power created by the movement of fluid compared to the entire area the fluid is contained in. These are used on a small scale as well as large depending on the size of the current meter. There are also propeller-type current meters that may also vary in size depending on the rate and volume they must measure. These flow meters are used by many different companies but most notably hydroelectricity plants that use large turbines to create electricity around the country.