A water flow meter is a key part of any plumbing or watering system. It is a measuring device that tells you the amount and speed of liquid that flows from the water source and through the pipes. Because homes and businesses need a continuous water supply, measuring and monitoring water flow is essential to ensure that the water system meets all requirements.
Many types of water flow meters are available for residential and industrial use, and choosing a suitable water flow meter for your setup is crucial. It can provide you with accurate flow readings that will help you determine if your watering system works efficiently, and identify potential issues or existing problems that need immediate resolution.
This article will look at the most common water flow meters and the situations they are used in.
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What Is Water Flow Rate?
The flow rate of water is the amount of liquid that moves inside a closed channel, like a pipe, and passes through an opening, such as a faucet, within a specific window of time. Water flow rate can vary based on various things, such as the surrounding environment, the speed or velocity of water flow, and the size and width of the water pipe.
Water Flow Rate Vs Water Pressure
Water flow rate is often confused with water pressure; however, the two terms have different meanings. Water pressure is the force that transports water through the pipelines and into your home or business. How high or low the water pressure is can be is affected by the elevation and the distance from the water source to your location. In addition, other factors, such as the presence of clogs or leaks in the plumbing system, can affect the pressure from the water source.
How Do Water Flow Meters Work?
Water flow meters are typically installed on the water mains or the pipes to measure whether the water flow is low or high. Most types of water flow meters have a plastic valve where water can flow through, a rotor that spins when water passes through it, and a screen that shows the flow readings. When water passes through the flow meter, the rotor will rotate and send the readings to the screen.
Newer versions of water flow meters have additional features in addition to measuring the rate of water flow; some have touch screen controllers and are Wi-Fi enabled. Other models can provide weather information such as temperature, humidity, and the possibility of rainfall.
Some irrigation controller sensors will measure flow rate, while other systems will require a separate water flow meter to be installed.
What Is The Difference Between A Flow Meter And A Water Meter?
Many people often confuse flow meters and water meters; however, they are different measuring instruments and have unique functions.
A flow meter measures the speed of liquid, which may be water, oil, or chemicals, as it flows through a channel. Some types of flow meters can even be used in measuring gas flow.
Meanwhile, a water meter is a form of flow meter that measures the amount of water flowing through a pipe. Water meters are commonly used in monitoring water usage as a way to calculate water bills.
What Types Of Water Flow Meters Are There?
Water flow meters vary based on the type of situation they are meant for, how they operate, and maintenance requirements. As a result, the different types can also vary in pricing. Below are the most common types of water flow meters.
Electromagnetic Water Flow Meters
Magnetic flow meters use a magnetic field to measure the water flow rate. In this type of flow meter, the magnetic field creates a charge that is sent directly to the device. Magnetic water flow meters are unsuitable for water systems with no contaminants as they need ions to generate voltage.
Mechanical Water Flow Meters
The distinguishing feature of a mechanical water flow meter is that it operates using a turbine or piston, which is equipped with a propeller. When water passes through the propeller’s blades, they rotate and send a pulse indicating the water speed. This way, changes in the rotational speed of the blade can show low or high-water flow.
Mechanical water flow meters are the most common type of flow meter in irrigation and water treatment systems. They are also the least expensive. However, mechanical flow meters may require higher maintenance costs because they can have blockages form when the water is dirty or slurry.
Ultrasonic Water Flow Meters
This type of water flow meter uses ultrasonic signals to measure water flow. Ultrasonic flow meters have two major subtypes: transit-time and clamp-on ultrasonic flow meters.
The transit-time ultrasonic meter works by sending an ultrasonic signal downstream before sending another one upstream. The two signals are compared to calculate the speed of water flow. Meanwhile, a clamp-on ultrasonic meter is installed on the outer wall of the pipe. It sends pulses through the pipes to produce flow measurements.
Vortex Water Flow Meters
As the name suggests, this water flow meter measures the vortex that water forms when it passes through an object measuring flow rate. A vortex flow meter has a sensor that flexes when a vortex comes in contact with it. The sensor tab then produces a pulse that accurately determines the water’s rate of flow.
Vortex flow meters have multiple models that, other than flow rate, also measure temperature, water density, water pressure, and mass flow. There are also insertion vortex meters that are suitable for measuring water flow rates in larger piping systems.
How Expensive Is A Water Flow Meter?
The price of water flow meters can vary from a few hundred dollars to more than a thousand. Mechanical water flow meters are the most affordable, are accurate in measuring flow rates but may require higher upkeep costs. Other types of flow meters, such as the vortex and ultrasound flow meters, may have higher upfront costs because they are equipped with more advanced technology that can deliver high precision flow readings.
What Is The Best Water Flow Meter For The Following Applications?
Best Household Flow Meter
Mechanical water flow meters are an ideal choice for residential properties. While they are a low-cost alternative to a more sophisticated water flow meter, mechanical flow meters can produce accurate readings. Often you won’t need a more advanced water flow meter than a mechanical one for residential use.
Best Caravan Flow Meter
In the caravan and camping industries, high-flow rates are expected. In addition, caravanning sites are also subject to warm temperatures. That’s why it’s best to use electromagnetic or ultrasonic flow meters.
Best Irrigation Flow Meter
For irrigation systems, mechanical water flow meters are a common choice. However, ultrasonic flow meters are also suitable, especially for large-scale irrigation systems. The flow meter you choose for your irrigation system will depend entirely on how large your system is. For irrigation around your family garden, a mechanical water flow meter is probably sufficient, but if you have a business growing crops, something more advanced like an ultrasonic flow meter is advised.
Related Questions
How Is Water Flow Measured?
To calculate the water flow rate, you need to determine the velocity of water and the shape, depth, and diameter of the channel that it passes through. In irrigation, the water flow rate is typically expressed in litres per minute (LPM). However, the flow rate may also be expressed in other units of measurement, such as gallons per minute (GPM) or cubic meters per second (m3/s).
The fastest way to calculate water flow rate is through the bucket test, measuring the time it takes to fill a bucket. For this, you would use a standard bucket (9 litres) and a timer. The best time to perform a bucket test is when water usage is at its peak.
Which Flow Meter Is Most Accurate?
Among all types of water flow meters, ultrasonic flow meters are considered the most accurate. Because ultrasonic water flow meters use ultrasound technology in measuring the rate of water flow, there are no obstructions or moving parts that can affect the flow readings. Obstructions and moving parts that are present in other types of flow meters are vulnerable to wear and tear and produce less accurate measurements over time.
How Can You Tell If Your Water Flow Meter Is Faulty?
There are several ways to tell if your water flow meter is not functioning correctly. When you see these tell-tale signs, it may be time to fix or replace your water flow meter.
- Scaling or accumulation of minerals such as sodium, calcium, and magnesium. These particles can affect water flow because they make the flow stream narrower. In worse scenarios, the build-up can get dense and flaky, which may cause the meter’s components to generate less accurate readings.
- Sludge, just like the build-up of minerals, can impact the flow of water. So when it gets thicker, the flow meter could produce less accurate measurements.
- Air bubbles can form in an open pipe system. For vortex flow meters, this can be a problem as air bubbles disrupt the vortex formation. Air bubbles are also a concern for ultrasonic flow meters because they can impede the movement of ultrasonic signals.
- Rust is a bane of anything made of metal that works near water. When rust forms inside the pipes, it can clog the water flow. When this happens, the meter can generate inconsistent readings.
Disclaimer:
This article is published for general informational purposes only and does not constitute professional advice. Any action you take upon the information you find on this website is strictly at your own risk. Always ensure you have the right qualifications and certifications to carry out DIY work and never put your safety at risk. Hills Irrigation recommends consulting a professional for all electrical and plumbing work.
Vince is Managing Director of Hills Irrigation and is supported by Lisa in an administrative capacity. Andrew, Isaac and Megan look after the day to day needs of both online and shop customers. As Project Manager, Vince is also responsible for installation projects along with his team. It is his responsibility to work closely with clients to ensure that scope of work is understood and followed.
