What Is Water Flow Meter And What Type Of Application Is Suited For It?

  • Published February 23, 2020
  • Flow Meters
  • by Proteusind

Water flow meters are 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. Water meters may also be used at water sources or throughout the water system to calculate the flow rate of a part of the system. Water flow meters may also measure the flow rate of slurries or fluids in closed pipes. The flow rate of water is measured in cubic meters (m3) or liters on an electronic or mechanical register.

A water flow meter is a device able to measure the amount of water crossing through a pipe. Various water flow meter technologies are open for choice depending on the water volume usage, economic terms, and keeping conditions. Each of these flow meter types has a novel process principle, overall value of use, and unique use advantages.

Water flow meters can measure hot water, cold water, clean water, dirty water, and slurries.

Two common methods are used in water flow meter measurement: velocity and displacement flow meters. Each type takes advantage of a variety of technologies.

Paddlewheel Sensors

The Paddlewheel sensor is a cost-effective and most commonly used water flow meter. It may also be used to measure the flow rates of water-like fluids. Many paddlewheel sensors are sold with insertion or flow fittings. Like turbine meters, they require 10 pipe diameters of straight pipe on the inlet and 5 pipe diameters on the outlet. The rotor of the paddlewheel sensor is fitted perpendicular to the flow rate. It will make contact with a limited cross-section of the flow.

Positive Displacement Flow Meter

This type of flow meter is used in applications where a straight pipe is not available and if a paddlewheel sensor and turbine flow meter would experience too much commotion. Positive displacement flow meters are used for viscous liquids as well.

A positive Displacement Meter is a flow meter requiring fluid to remove particles in the meter for flow analysis automatically. PDM scale a moving fluid or gas volumetric flow rate by splitting the media into fixed, metered masses.

These tools consist of a chamber that stops the media flow and a revolving or reciprocating mechanism that lets fixed volume results. The number of cases that pass through the section considers the media mass.

The rate of rotation or reciprocation determines the flow rate. There are two basic kinds of positive displacement flow meters. The sensor only systems or transducers are switch-like tools that give electronic makings for processors, controllers, or data recovery systems.

Positive Displacement Flow Meters Types:

  • Reciprocating or oscillating piston

Each piston is automatically or magnetically conducted to fill a cylinder with the fluid and then remove it. Each stroke describes a limited analysis of the liquid.

  • Gear

Gear flowmeters rely on inner gears rotating as fluid crosses through them. There are several kinds of gear meters named often for the shape of the internal parts.

  • Oval Gear

Two rotating oval gears with organized teeth press a limited quantity of fluid through each rotation meter. An oval gear flow meters, two oval gears, or rotors are fixed inside a cylinder.

As the fluid flows through the cylinder, the force of the fluid makes the rotors turn. As the flow rate rises, so does the rotational velocity of the rotors.

  • Helical Gear

The name Helical gear flow meters get from the shape of their gears or rotors. These rotors match the style of a helix, which is a spiral formed structure.

  • Nutating disk

A disk fixed on a circle is shuffled about an axis by the fluid flow, and each rotation describes a limited volume of fluid carried. A nutating disc flow meter has a round disc fixed on a shaft in a cylindrical chamber.

The flow meter defines the number of times the chamber pits and removes fluid by tracing the spindle’s moves. This data is used to discover the flow rate.

  • Rotary vane

A rotating impeller holding two or more vanes breaks the areas between the vanes into distinct sizes, and each rotation is added.

  • Diaphragm

The fluid is moved into the inlet side of an oscillating diaphragm and then dispersed to the outlet. The diaphragm oscillating cycles are included in determining the flow rate.

Magnetic Flow Meters

This type of flow meter does not have moving parts and used in wastewater applications or with dirty liquids that are conductive. Displays are an important part of this type of flow meter which can be used for data logging or remote monitoring.

Magnetic flowmeters include a fluid crossing speed through a pipe using a magnetic field to regulate the volumetric flow. They are based on Faraday’s Law of Electromagnetic Induction, according to which liquid produces a voltage when it runs through a magnetic field. The faster the fluid flow, the more the voltage is produced. The voltage generated is directly equal to the water movement; the voltage sign is prepared into the electronics’ volumetric flow rate. Since the magnetic flowmeters show an average accuracy, they are not fit for keeping transfer uses. They cannot be used to measure pure water as there are no atoms to count.

How Magnetic Flowmeters Work

Magnetic flowmeters apply Faraday’s Law of Electromagnetic Induction to discover the flow of liquid in a pipe. A magnetic field is produced and channeled into the liquid running through the line in a magnetic flowmeter. Following Faraday’s Law, the course of a conductive liquid through the magnetic field will make a voltage signal to be sensed by electrodes placed on the flow tube walls. When the fluid moves faster, more voltage is formed. Faraday’s Law says that the voltage created is equal to the flow of the running liquid. The electronic transmitter prepares the voltage signal to discover liquid flow.

In contrast with several other flowmeter technologies, magnetic flowmeter technology generates signals that are direct with the flow. As such, the turndown linked with magnetic flowmeters can reach 20:1 or better without reducing power. They signify about 23% of all flowmeters sold.

Main Application Cautions for the Magnetic Flowmeters

  • Do not turn a magnetic flowmeter near its electrical conductivity limit because the flowmeter can turn off. 
  • Give an interest in changing production and working situations that can change the electrical conductivity of the liquid.

In daily uses, magnetic flowmeters are sized so that the highest flow speed is about 2-3 meters per second. Different pressure forces and process states may limit the use of this overall guideline. 

Ultrasonic Flow Meters

This flow meter is used in applications where sewage and dirt are involved such as wastewater, slurries, and other dirty liquids. This type of water usually damages conventional flow meters. Ultrasonic flow meters operate on the principle that a frequency shift of the ultrasonic signal occurs when it is reflected by gas bubbles or suspended particles in motion. This is also known as the Doppler Effect.

Ultrasonic water flow meters cover the speed of fluid moving through the pipe using ultrasound to estimate the volumetric flow. In a transit time ultrasonic liquid flow meter, an ultrasonic sign is given in the way of the flowing fluid downstream. Then another password is sent against the flowing fluid upstream.

How Ultrasonic Flowmeters Work

Ultrasonic flowmeters use sound waves to discover the speed of a fluid flowing in a pipe. At no flow situations, the frequencies of an ultrasonic wave sent into a pipe, and its reflections from the fluid are the same. Under flowing positions, the frequency of the reflected wave changes due to the Doppler effect. When the fluid moves quicker, the frequency shift grows linearly. The transmitter gives signals from the transmitted wave and its reflections to discover the flow rate.

Transit time ultrasonic flowmeter gives and accepts ultrasonic waves between transducers in both the upstream and downstream places in the pipe. In no flow situations, it takes the same time to move upstream and downstream within the transducers. Beneath flowing conditions, the upstream wave will travel gradually and take longer than the downstream wave. When the fluid moves faster, the distinction between the upstream and downstream times rises. The transmitter lets upstream and downstream times to discover the flow rate. They express about 12% of all flowmeters sold.

Main Application Cautions for the Ultrasonic Flowmeters

  • For infiltration time ultrasonic flowmeters, be assured that the fluid can suitably conduct ultrasonic waves. 
  • The flowmeter will not regulate when the ultrasonic waves cannot perceive the flow stream between the transducers.
  •  Thus, ultrasonic waves must be able to understand the fluid for Doppler flowmeters to work correctly. 
  • When the fluid is thick and does not clean the fluid, Doppler flowmeters help set the fluid’s velocity at or near the pipe wall, which can cause vital measure error and letting the flowmeter fail.


Your application features conclude the perfect water flow meter type. Some flowmeters work better than others in certain conditions. Your time and energy can be saved by making a learned choice, so don’t delay giving us a call if you are still doubtful.

If you are looking for perfect flow meters for your industry, no company can provide better products than Proteus Industries Inc. The company is committed to developing innovative and high-quality flow management products to provide customer satisfaction.

The company features several types flow meters and switches to choose from keeping your requirements in consideration. The company offers a complete line of flow meters and management devices at the highest specifications in the industry.

The company assures world-class calibration capability that allows delivering flow meters with specialized temperature and fluid specific calibrations. The company’s flow meters monitor the cooling flow in industrial applications to ensure the safety of all.

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