What are flow meters, their types, their different applications and what factors to take into consideration while choosing a flowmeter will be covered in this article?

What is water flow meters?

A water flow meter is an instrument that measures the volume of water flowing through a pipe accurately, allowing you to determine the current flow rate.

liters or meters cubed per minute (L/min = m3/min), or gallons per minute (gal/min) are the most common units used to measure the water flow rate.

Hot water, cold water, clean water, turbid water and slurries can all be measured with water flow meters.

How do water flow meters work?

Water flow meters come in a variety of shapes and sizes, but they always do the same thing: they measure the amount of moving water, either directly or indirectly.

Flow meters detect water flow using various technologies, including mechanical gears, electromagnetic and ultrasonic technology.

Simply, the Water flow rate can be detected by measuring how long it takes a volume of water to pass through the flow meter and express it in liters per minute.

All flow meters include four essential components:

A sensor: to detect the water flow.

A transducer: converts and transmits the flow signal.

A counter: to track the volume of water that flows through the sensor. The counter maps the pulses sent through the meter to determine the volume and/or flow speed.

An indicator: to display the meter reading

What are the different types of water flow meters?

Each water flow meter has its unique operating principle, as well as distinct application advantages.

Mechanical flow meter

Or positive displacement flow meter this type of flow meter used moving parts such as a physical wheel or gear that spins due to water flow.

Therefore, the gear spins and this rate is proportional to the water flow rate and can be converted to a volumetric flow rate, as is the goal of a flow meter.

Positive Displacement Flow Meters Types

Reciprocating or oscillating piston: where Each piston is automatically or magnetically guided to fill and then empty a cylinder with fluid

Gear: Inner gears in gear flowmeters rotate when fluid passes past them. The shape of the internal pieces is commonly used to name the different types of gear meters.

Oval Gear: A restricted amount of fluid is pressed through each rotation meter by two spinning oval gears with arranged teeth.

Two oval gears, or rotors, are fixed within a cylinder by an oval gear flow meter.

The rotational velocity of the rotors increases as the flow rate increases.

Helical Gear: The shape of the gears or rotors on helical gear flow meters gives them their name.

These rotors are designed to look like a helix, which is a spiral-shaped structure.

Nutating disk: The fluid flow shuffles a disc set on a circle about an axis, and each rotation depicts a finite volume of fluid conveyed.

A nutating disc flow meter consists of a circular disc mounted on a shaft and housed in a cylindrical chamber.

limitation: Because the physical part of the meter is spun by the water, if the water is highly unclean or includes big impurities, a mechanical flow meter can rapidly decay and break.

As a result, mechanical flow meters are best suited for procedures or applications involving clean water.

Mechanical water meters also don’t work well with a low flow of water.

Vortex flowmeter

Vortex water flow meters work by measuring the vortices created by a sensor submerged in the flow.

Vortices are natural forces that generate “swirls” as a fluid passes around an impediment, such as water flowing around a rock in a stream or wind passing through a flagpole.

As each vortex passes through a vortex meter, a sensor tab flexes from side to side, providing a frequency output that is directly proportional to the volumetric flow rate.

multivariable vortex flowmeters can measure up to five process variables: volumetric flow rate, mass flow, density, pressure and temperature.

These meters work particularly well with large pipes

Ultrasonic Flow

Ultrasonic water flow meters estimate volumetric flow by measuring the speed of a fluid moving through a pipe.

An ultrasonic signal is transmitted downstream in the direction of the flowing fluid, and then another signal is transmitted upstream against the flowing fluid in a transit-time ultrasonic liquid flow meter.

The time it takes for a sonic pulse to move downstream is compared to the time it takes for the pulse to go upstream in its most basic form.

The velocity of the flowing stream is then calculated using the differential time.

The meter then calculates the volumetric flow rate in the pipe using this fluid velocity.

Application: ultrasonic flow meters work well with large pipes as they can be installed on the outside of the pipe.

Single and Multi-jet Flow Meters

Like a mechanical flow meter, the meter channels water into an internal propeller and monitors the speed at which the propeller blades spin.

Limitation: Because they do not work at high or huge flow rates, jet flow meters are best suited for small-scale applications.

Because the parts are in direct contact with water, this meter is best suited for domestic and clean water applications.

Turbine Flow Meters

Turbine meters use the mechanical energy of a liquid to spin a rotor in the flow stream.

The rotating speed of the rotor is related to the fluid velocity passing through the meter.

Application: Turbine meters are a good choice for applications with stable, high-speed flows and a high level of precision. Provides a high degree of consistent accuracy at a low cost of operation. Best suitable for clean water.

Magnetic Flow Meter

Magnetic flowmeters manage volumetric flow by regulating the fluid crossing speed through a pipe using a magnetic field.

They are based on Faraday’s Law of Electromagnetic Induction, which states that when a liquid passes through a magnetic field, it produces a voltage.

The voltage produced is proportional to the rate of fluid flow.

The voltage created is proportional to the amount of water moving through it; the voltage sign is factored into the volumetric flow rate of the electronics.

Application and limitation: Magnetic flowmeters are not suitable for keeping transfer usage because their precision is middling.

There are no atoms to count, hence they can’t be used to test pure water.

While magnetic flow meters are suitable for wastewater applications, data logging, and remote monitoring.

The difference between a water flow meter and a flow meter

While all water meters are flow meters, not all flow meters are water meters.

The difference between a water meter and a flow meter is that a water meter monitors the volume of water passing through the meter, while a flow meter measures the speed at which the water travels through the meter.

Another significant distinction is that water meters are only used to measure water, but flow meters are utilized in a variety of industrial applications to measure liquids such as oil, milk, honey, and so on.

Flow meters are also used to measure gases in addition to liquids.

A water meter is used almost exclusively for billing purposes. While a flow meter is used in a wider range of monitoring situations.

Factors to take into consideration

To select the best water Flowmeter which will fit your requirements, you should consider a few factors these factors include:

1. The accuracy of the meter

2. The lifespan of the flowmeter

3. The operational needs

4. Maintenance requirements

5. overall cost

6. The range of flow rates that the meter can handle

7. Water quality

Overall, the cleanliness of your water, your budget and the precision of your flow measurements will determine which water flow meter is most suited for your application.

For dirty water with large particulates, lean more towards magnetic, ultrasonic, and vortex meters to prevent many maintenance headaches.

For smaller scale, cleaner water applications, lean on the turbine, mechanical and jet flow meters to accurately measure the flow rate.

References

[1] Water Meters vs Flow Meters, November 10, 2020, [online] Available at: https://arad.co.il/blog/water-meters-vs-flow-meters/

[2] How Does a Water Flow Meter Work? Oct 27, 2017, Scott Rouse, Product Line Director [online] Available at: https://www.sierrainstruments.com/blog/?water-flow-meter-work

[3] What Is a Water Flow Meter and What Type of Application Is Suited for It? February 23, 2020, by Proteusind [online] Available at: https://proteusind.com/what-is-water-flow-meter-and-what-type-of-application-is-suited-for-it/

[4] Turbine Flow Meters [online] Available at: https://www.badgermeter.com/products/meters/turbine-flow-meters/#SubNavAnchor__How_It_Works

[5] Exploring the Different Types and Applications Water Flow Meters, 07/27/2020 [online] Available at: https://sensorex.com/2020/07/27/exploring-the-different-types-and-applications-water-flow-meters/

[6] Choosing A Water Flow Meter Type That’s Right for You, April 29, 2021 [online] Available At: https://atlas-scientific.com/blog/water-flow-meter-types/