A flow meter is a device to measure the amount of liquid flowing through a pipe and the quantity of the liquid streaming. It is of utmost importance in any industry as it not only quantifies the liquid but also detects leakages by which the wastage can be avoided. Different kinds of liquid flow meters are used in varied fields and are highly essential for the industrial use. Incorrect data given by an erroneous flow meter can produce disastrous results. With the change in the kinetic energy of the flowing liquid, the flow rate is determined. The velocity, on which the kinetic energy varies, depends on the pressure projection that makes the liquid flow through the pipe. The other influencing factors are density, viscosity and the friction of the liquid with the inner walls of the pipe.
Various Categories of the Flow Meter:
There are different kinds of liquid flow meters, depending on the circumstances in which the flow meters are used.
The closed pipe flow meter is a type of flow meter that is used for fluids flowing in a closed conduit like sewer, kitchen pipeline, water pipeline, fuel pipeline, etc. and the open channel includes measuring the flow in a non-constricted area. The meters are placed near the pipelines to get the accurate result and it is displayed on the meters attached to the conduits. The closed pipe flow meter can be divided into differential pressure, positive displacement, velocity, and mass flow meters. And the open channel can be categorized into weir and flumes.
- Differential Pressure Flow Meter:
Being the most common flow meter in use, it has primary and secondary component. The first component changes the kinetic energy and the second one measure the differential pressure, which produces a signal that can be changed to get the flow rate. They can further be divided into Venturi Tube, Orifice Plate, Flow Tube, Flow Nozzle, and Rotameter.
This flow meter operates directly with the volume flow rate. It translates the data of the velocity of water into its volume. When the flow meter is used with Reynold’s number greater than 10,000, the flow meter becomes insensitive to the viscosity change of the fluid. They can be divided into Vortex Shedding, Turbine, Swirl, Electromagnetic, Ultrasonic Doppler, Pilot Tubes, and Calorimetric.
- Positive Displacement Flow Meter:
The flow of water is measured by correlating it with the number of times the chamber is filled and emptied with water. It includes Nutating Disc, Rotary Vane Meter, Reciprocating Piston Meter, and Oval Gear.
This flow meter measures the mass of fluid flowing through a particular point per unit time. This flow meter consists of Coriolis and Thermal Flow Meter.
It refers to the liquid flowing in the free surface and analyzes the flow rate by measuring the water depth. It has two categories- Weirs and Flumes.
These flow meters have become an integral part of both the commercial and domestic domain.