Several Water Flow Meter Technologies and How do they Work?

water flow meters- Several Water Flow Meter Technologies and How do they Work?

Water Flow Meter is a device used to measure the volume of water used in commercial and residential buildings. The water is supplied to homes and offices via a public water supply system for various applications.

How water flow meter works?

This mechanical water flow meter works by measuring the speed of flowing water running through the pipe that causes the turbine or Piston to rotate.

Types of water flow meter

There are four standard water flow meters mentioned below; mechanical water flow meters, Ultrasonic flow meters, vortex volumetric flow meters, and magnetic flow meters. This article will discuss their working principle, applications, some of their advantages and disadvantages.

1. Ultrasonic flowmeters

 Ultrasonic flow meters are water flow meters that measure the velocity of the liquid flow meters within ultrasound to calculate its volume flow. It uses sound waves to estimate the flow of substances in pipes or pumps.

How do ultrasonic flow meters work?

Ultrasonic flow meters work by sending sound waves too high for humans to hear. They then wait for the sound to be reflected, calculating the distance based on the required time.

Types of ultrasonic flowmeters

The common types of ultrasonic flow meters are; the drip-proof type, open structure type, frequency and shape type, and open structure type.

Advantages of ultrasonic flowmeters

i) They are the favorable choice of materials for chemically aggressive liquids.
ii) There is a linear relationship between flow rate and measured variable.
iii) Ultrasonic flow meters require low maintenance costs.
iv) Ultrasonic flow meters do not have moving parts hence are not subjected to wear and tear.

Disadvantages of ultrasonic flowmeters

i) Ultrasonic flow meters typically have errors due to deposits.
ii) Doppler meters are only for slight contamination or few gas bubbles.
iii) The ultrasonic flow meters typically required a long inlet and outlet section.
iv) The sound beam must traverse a representative cross-section; therefore, the flow profile is dependent.
v) Ultrasonic flow meters are problematic for liquid and gas measurements.
vi) Doppler meters are affected by sound velocity changes due to temperature.
vii) Transit time meters required clean liquid; hence they are costly.

Application of ultrasonic flow meter

Ultrasonic is commonly applied to measure the velocity of liquids that allows ultrasonic waves to pass, such as water, molten, sulfur, cryogenic liquids, and chemicals.

2. Vortex volumetric flowmeters

The vortex flowmeter is a flow measurement device best suited for flow measurements where the introduction of moving parts presents problems.

How the vortex flow meters operate

Vortex flowmeters operate under the shedding principle where a layer of vortexes occurs when a fluid such as water flows past a bluff.

Advantages of vortex flowmeters

The following are the advantages of vortex volumetric flow meters.

i) Vortex flow meter is suitable for liquids, gases, and steam.
ii) Vortex volumetric flow meters are easily sterilizing.
iii) They are not affected by pressure, temperature, and density changes.
iv) Vortex volumetric flow meters have no moving parts.
v) There is a personal relationship between the flow rates and measure value.
vi) Vortex volumetric flow meters have rugged construction.


Vortex volumetric flow meters have the following disadvantages;

i) They require an inlet and outlet section.
ii) Vortex volumetric flow meters required. Minimum Reynolds.


Vortex flow meters are ideal for measuring saturated and supersaturated steam in extensive facilities to improve steam production, efficiency, and allocation.

3. Mechanical water flow meter

It works by measuring the speed of water flowing through the pipe that causes a piston or turbine to rotate. The volumetric flow rate of the water is proportional to the rotational speed of the blades. Mechanical flow meters do not work well when the water flow is low.

The following are the available features you should consider when selecting an appropriate mechanical water meter for your application:

i) It should be easy to maintain and require removable mechanisms.
ii) It should have reliable and sensitive metrology and low-pressure loss.
iii) The impeller protects by a metallic cover.
iv) Meter should be leakproof; hence it seals in the metallic outer body.
v) One should be able to repair it without affecting the regular water supply.

Two types of Mechanical water flow meters are; volumetric flow meters and mass flow meters.

Advantages of mechanical water flow meters

i) They require lower inline maintenance.
ii) Mechanical volumetric flow meters are relatively inexpensive during initial installation.
iii) The mechanical flow Meter is always reliable, and one can rely on it.
iv) Mechanical flow meter also provides accurate measurements.


The following are the limitations of the Mechanical water flow meter.

i) It is affected by wear due to soft water; this results in loss of accuracy, which requires frequent replacement.
ii) The mechanical flow Meter has a shorter life service.
iii) Mechanical water flow meters have some head loss.
iv) Mechanical parts get damages, which require frequent accuracy testing.

Application of Mechanical flow meter

They use to arrange moving parts, either by passing specific, known volumes of a fluid through a series of gears or chambers or using a spinning turbine or rotor.

4. Magnetic flowmeters

It measures fluid flow by the voltage induced across the liquids by its flow through a magnet.

Application of magnetic flowmeters

Magnetic flowmeters use in liquid treatment plants to measure treated and untreated sewage, process, water, and water chemicals.

Types of magnetic flow meter

There are three basic types of magnetic flowmeters: insertion, inline, and low flow.

Disadvantages of magnetic flowmeters

i) Magnetic flow meters have no additional pressure drop.
ii) Magnetic flow meter is suitable for reliable acid transport.
iii) It affects by changes in temperature, density, velocity, concentration, and electrical conductivity.
iv) Magnetic flow meter has no obstruction to flow.

Advantages of magnetic flowmeters

i) Magnetic flow meters are generally non-invasive.
ii) They have no moving parts, hence reduced risk of breakdown and frequency of repairs.
iii) They have excellent repeatability.


Water flow meters are essential devices in various industrial applications. Multiple types of water flow meters operate in different ways. Your application will determine which type of water flow meter to use for you to obtain accurate results.


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