In our modern world of web-dependent self-reliance, information of all kinds is available to all searchers on the interweb. Why should the secrets of flow meters be far behind? Here are 4 basic kinds of flow meters to help you out on a rainy day:
Volumetric flow meters:
The volumetric flow meter directly measures flow rate by calculating the total volume of fluid that passes through the flow meter itself. The only device that uses this technology is the positive displacement flow meter, which measures the flow rate of corrosive and non-corrosive liquids without any kind of dirt or deposits in them.
These are finicky to maintain and hence it is important to regularly clean the deposits or dirt that may accumulate in the flow meter, preventing drainage. Plugging can seriously affect the meter’s accuracy and eventually result in complete blockage. These meters are often used by municipalities to measure consumption of water.
Inferential flow meters:
Inferential flow meters “infer” flow rates indirectly by measuring factors such as pressure or area. Differential pressure and variable area flow meters are two devices that use this method. The first is often used to measure the flow of cryogenic liquids, while the second is used for clean and clear liquids by laboratories and industries such as the paper and pulp industry.
Velocity Flow meters:
These flow meters measure the velocity of the fluid stream, to calculate the flow of the total volume. This technology is used by a vast variety of devices, including ultrasonic, magnetic and turbine flow meters, for a diverse range of purposes. Each comes with its own requirements: ultrasonic meters, for example, ought not to be used with opaque liquids, magnetic flow meter can be used for corrosive liquids in chemical feed systems and turbine flow meters can be used for distribution of water, and so on.
Mass flow meters:
These measure the mass of the fluid flowing through them. Coriolis mass and thermal flow meters use this technology. The latter, unaffected by density changes, may be used to measure products of extremely high value (such as mining, mineral processing and petrochemical materials), and thermal flow meters usually measure the mass flow of clean gases, such as air, nitrogen and argon, many times for usage in laboratories.
Coriolis flow meters are adversely affected by pressure changes. It is therefore important to make sure that the device is filled completely with the fluid it is supposed to measure at all times. On the other hand, thermal flow meters must not be used in corrosive fluids, as the thermal sensor can then be damaged.
There is no “one size fits all” approach to flow meter installation, and it is neither available nor advised. It is better to go about by keeping in mind the usage of the device, rather than the kind of technology it uses, as most of the above-listed methods are applicable in multiple cases. Hope this helps, and happy plumbing!