Flow Meter Strategy: How It Works | Expectations vs. Reality

flow meter strategy
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Have you heard about a flow meter? 

Your mind may have had a lot of thoughts on what it could be if you have never seen it. But it’s just a device. It is mainly used to measure the volume of liquid or gases.

With a flow meter, you can measure open channels like streams or rivers. Do you seek to improve the resolution, accuracy, and precision of fluid measurement? You will never go wrong with a flow meter.

You will find many flow meters in the market. While flow meter sensors may work in different ways, the results will always be the same. They will give you the most accurate and reliable flow results for your application. It may be for research activities or process control.

How Flow Meter Functions

It’s important to understand that all flow meters do not function the same way. There is velocity, mass, and positive displacement flow meters. Each of them works differently for the other. But you can be sure any you install will give you accurate results on what you are going to measure. Here are flow meters and how they function. You can select any based on what you are going to measure.

Magnetic flow meter

Do you seek a magnetic flow meter? You can use it to measure liquid substances. But the substance you want to measure must be conductive or water-based. If you want to measure the dirty water or the one you shouldn’t come into contact with, go for a magnetic flow meter. It’s a great choice device to use that can offer you accurate results while securing your safety. 

Once you have installed your magnetic flow meter, it will help you measure without your fluid touching on your body or clothes. It is most ideal in areas you would not like to expose yourself to the liquid being measured. A magnetic flow-meter is a volumetric meter with no moving parts. 

The flow meter functions depending on Faraday’s formulae. The liquid you are measuring needs to be conducted. While using this flow-meter, a voltage is measured, but it depends on the average velocity of the liquid being measured. That is multiplied by the strength of the magnetic field and the length of your conductor. 

Mechanical flow meter

You can go for this flow meter. But remember it has internal mobile parts that can’t fit in certain applications. If you are going to measure dirty water that carries large particles, this flow meter won’t be the best choice for you. Those particles may lead to damage or obscure the internal mobile parts from functioning. If that happens, you aren’t going to get reliable flow results.

The mechanical flowmeter is fixed with a rotational device within it. It looks like a paddlewheel. When the liquid you measure flows through the pipe, it makes the internal paddle rotate. The pressure resulting will create a flow rate that is relative to the speed of rotation of the internal paddle. If you are looking for a low meter to understand with ease, you can go for this type.

Ultrasonic flow meter

This flow meter applies ultrasonic beam impulse pulses to help measure the flow of fluids. You can go for Doppler or transit-time flowmeter. The transit-time flowmeter has multiple sensors. That is upstream as well as downstream on the external line.

 The fluid you measure flow with one beam against the other. So, the difference in terms of time between the two beams to move within the elements is applied to get the flow rate. Ensure the transit-time ultrasonic flowmeter gets clean service. The presence of particles, as well as bubbles, may alter the pulse. That will create noises, and signals will be lost, which affects the working of the flowmeter. 

If you pick a Doppler flow meter, it will use one transmitter or sensor. The sensor shoots an ultrasonic pulse into the line. That will reflect off the particles as well as bubbles. Doppler flow meter uses a Doppler Effect to help measure changes in pulse frequency. That way, you can easily infer the rate of flow of the liquid you are measuring.

Doppler ultrasonic flow-meter needs bubbles or particles within the liquid you measure for it to function well. This kind of flow meter offers you a high degree of precision and turn-down. It never restricts the flow path. You can get this flow meter on the clamp-on type. Doppler ultrasonic flow meter has vital upstream and downstream needs you should meet. You are required to position its sensor well for it to be effective.

Coriolis flow meter

This flow meter applies inertial force from the flowing liquid to add change to the vibration of a set of tubes. You can then measure the Coriolis Effect in terms of frequency, amplitude as well as the phase change to help you determine the rate of flow. That can also help you find the density of the fluid you measure within the system.

You are supposed to induce vibration inside a tube through which the fluid you measure flows. Once you are done, the plane of the vibrating tube will give you a reference frame to allow you to measure the Coriolis Effect. The specific methods may be different based on the flow meter design.

But the sensors will monitor and analyze the change in frequency and phase shift. They also check the amplitude of the vibrating flow tubes. You will be required to observe the changes so that to calculate the rate of flow and density of your fluid.

Inside two tubes with a u-shaped design, your fluid will flow via parallel tubes. Then, an actuator will induce tube vibration. Two parallel tubes will counter vibrate. That will make your measuring devices have reduced sensitivity to the outside vibrations.

Don’t forget the rate of the vibration will be subject to the size of the flow meter. It can range from eighty to about 1000 vibrations within a second. The breadth is small, and it’s hard for you to see it, but you can feel it through touch. 

When you don’t have any fluid flowing through your flowmeter, the two tubes vibrate in a balanced manner. The tubes will have some twist in case there is mass flow. An arm upon which your fluid flows away from the axis of the rotation will exert force to the fluid, and that will raise the fluid’s angular momentum.

That will lag behind the general vibration. The arm via which your fluid is pressed towards the axis of rotation will exert force on the fluid. That will decrease the angular momentum of the fluid. So, that arm will result in the overall vibration.

Your inlet, as well as the outlet arms, will vibrate through the same frequency just similar to the overall vibration. But the presence of mass flow makes the two vibrations go out of sync. Your inlet arm is left behind while your outlet remains ahead. The two vibrations will change in phases with respect to one another. The extent of phase change is linked to the amount of mass flowing via the tubes.

Expectation VS. Reality on How Flow Meters Function

Expectation 1

You may be expecting that pressure plays a big role in the function of the Coriolis flowmeter.


When using a Coriolis flow meter, it’s never sensitive to change in pressure, density, viscosity, or temperature. They will always offer a flow path with no obstruction.

Expectation 2

All the flow meter works the same after you have installed them.


There are different types of flow meters and usually work in different ways. But the goals are just the same.

Expectation 3

You expect all the flow meters not to function well due to bubbles and particles in the system.


While the presence of particles and bubbles affects many flowmeters, the fact is Doppler ultrasonic flowmeter needs bubbles or particles within the liquid you measure for it to function well.

Expectation 4

Due to the high technology applied in coming up with a flowmeter, you may expect them to be too expensive.


While some are too expensive based on the types, some are cheap and affordable.

Expectation 5

Installation is quite simple for all the flow meters.


Not all the flow meters can be easily installed. Some have complex installation processes that you will require an expert to fix for you. But there are some you can fix by yourself without hassle.

Expectation 6

All flow meters have mobile parts.


While some have mobile parts that can be affected by particles within the fluid that flow in the system, the magnetic flowmeter doesn’t have mobile parts.

Expectation 7

Once you have installed your flowmeter, you may expect not to carry out any maintenance, and they will just function normally.


The installation of the flowmeter is not the end. You will be required to carry a periodic check on them to ensure everything is functioning well. Don’t forget that some have moving parts that can be easily affected by particles carried by the liquid you are measuring.

Besides, due to the abrasive nature of the fluid you are measuring, the particles in it as well as the channel the fluid is flowing in, there will be tear and wear. This requires proper monitoring to rectify any breakdown.


A flowmeter is very vital for research activities and control processes. You will find different types of flowmeter in the market. While don’t functions the same way, their goals are similar. Ensure to choose a flow meter that suits well the liquid you are going to measure.

Author Byline

Naman Modi is a Professional Blogger, SEO Expert & Guest blogger at ProteusInd, He is an Award Winning Freelancer & Web Entrepreneur helping new entrepreneur’s launches their first successful online business.

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