Our Guide to Flow Meters
Flow measurement plays a critical role across countless industries, from water treatment and food production to pharmaceuticals, oil and gas and energy generation.
Whether it’s monitoring water usage, measuring steam consumption or tracking compressed air flow, choosing the right flow meter is essential for accuracy, efficiency and process control.
In this blog, we’ll explain what a flow meter is, how flow meters work, the different types available and how to choose the right solution for your application.
What is a Flow Meter?
A flow meter is a device used to measure the movement of liquids, gases or steam through a pipe or process system. Depending on the technology used, a flow meter can measure:
- Flow velocity
- Volumetric flow
- Mass flow
- Energy consumption
Flow meters are used to help businesses:
- Monitor process efficiency
- Reduce waste and leakage
- Improve energy performance
- Support billing and compliance
- Gather accurate operational data
From a simple water flow meter in a residential property to highly advanced industrial monitoring systems, flow meters provide the data needed to make informed decisions.
How do flow meters work?
The way a flow meter works depends on the technology being used and what is being measured.
Some flow meters measure the speed of a liquid or gas passing through a pipe, while others calculate mass or energy using temperature, pressure or density data.
Modern flow meters can also integrate with cloud-based systems, dashboards and remote monitoring platforms to provide real-time data and predictive maintenance analytics, like our data platform Brella.
Types of flow meters
There are many different types of flow meters available, each suited to specific applications, industries and process conditions. Below, we will dive a little deeper into the various types.
Coriolis flow meter
A Coriolis flow meter measures mass flow directly using vibrating tubes. As liquid or gas passes through the meter, the vibration changes slightly, allowing the device to calculate flow and density with extremely high accuracy.
Coriolis meters are commonly used in:
- Food and beverage manufacturing
- Chemical processing
- Pharmaceutical production
- Oil and gas
They are particularly valuable where precision and repeatability are critical.
Electromagnetic flow meter
An electromagnetic flow meter (often called a mag meter) uses Faraday’s Law of Electromagnetic Induction to measure conductive liquids.
They are commonly used across utilities and process industries. Because there are no moving parts, electromagnetic flow meters are highly reliable and well-suited to:
- Wastewater
- Clean water
- Slurries
- Industrial liquids such as chemicals and acids
Vortex flow meter
A vortex flow meter measures flow using vortices created as fluid passes around a bluff body inside the pipe.
These meters are particularly effective for:
- Steam measurement
- Gas flow
- High-temperature applications
Vortex technology is widely used in energy-intensive industries where steam monitoring is essential for efficiency and compliance.
Clamp-on ultrasonic flow meter
A clamp-on ultrasonic flow meter uses sound waves to calculate the flow velocity of liquid, gas, steam, water, thermal energy and compressed air to provide velocity, energy, mass and volumetric data.
A clamp-on ultrasonic flow meter provides non-invasive flow measurement by attaching ultrasonic sensors to the outside of a pipe. This allows businesses to gather accurate data without interrupting operations.
Many ultrasonic flow meters use the transit-time principle, where sound signals are sent both with and against the direction of flow. The difference in travel time allows the meter to calculate flow rate accurately.
Unlike traditional inline meters, clamp-on systems do not require pipe cutting, intrusive installation or process shutdowns. This makes them ideal for:
- Temporary surveys
- Energy monitoring
- Verification checks
- Difficult or hazardous installations
The ability of clamp-on ultrasonic systems to measure steam non-invasively is a major advancement in industrial flow measurement technology.
Thermal mass flow meter
A thermal mass flow meter is primarily used for measuring gases. It works by monitoring how heat transfers from a heated sensor into the flowing gas stream.
Thermal mass flow meters are commonly used in:
- Biogas applications
- Combustion systems
- Compressed air monitoring
- Anaerobic digestion plants
Because they directly measure mass flow, they can provide highly accurate readings even where temperature and pressure fluctuate and can be used at the lowest flow rates.
Variable area flow meter
A variable area flow meter, often known as a rotameter, measures flow using a float inside a tapered tube. As the flow increases, the float rises. They can function as an excellent mechanical backup meter because no external supply is needed.
These meters are simple, cost-effective and commonly used for:
- Basic liquid measurement
- Laboratory applications
- Low-flow processes
Multiphase flow meter
A multiphase flow meter measures mixtures of oil, gas and water flowing together in a pipe. Multiphase technology helps operators monitor production without separating the fluids first.
These are widely used in:
- Oil and gas production
- Offshore platforms
- Complex process environments
Water flow meter
A water flow meter is used to measure the flow rate or volume of water moving through a system. These are commonly used in:
- Water treatment plants
- Utilities and infrastructure
- Commercial buildings
- Manufacturing facilities
Different technologies can be used depending on the application, including electromagnetic, ultrasonic and mechanical flow meters.
Air flow meter
An air flow meter measures the movement of air or gas through a system. These are widely used in:
- HVAC systems
- Compressed air networks
- Industrial processing
- Combustion control
Accurate air flow measurement can help reduce energy waste and improve operational efficiency.
Applications of flow meters
Flow meters are used in almost every industrial sector. Common applications include:
- Measuring steam and thermal energy
- Tracking compressed air usage
- Process optimisation
- Energy efficiency monitoring
- Supporting net zero and sustainability initiatives
- Monitoring water consumption
- Leak detection
- Billing and compliance reporting
As businesses increasingly focus on sustainability and operational efficiency, accurate flow measurement and data visibility are becoming more important than ever.
Choosing the right flow meter
Choosing the right flow meter depends on several factors, including:
- What you are measuring (gas, water, steam, etc.
- Pipe size
- Temperature and pressure
- Required accuracy
- Whether invasive or non-invasive installation is preferred
- Maintenance requirements
- Data and integration needs
For example, a clamp-on flow meter may be ideal where shutdowns are not possible. A Coriolis flow meter may be best for highly accurate mass measurement; meanwhile, an electromagnetic flow meter is well-suited to conductive liquids.
If you’re looking to measure gas, a thermal mass flow meter is usually the preferred choice.
The best solution is one that balances performance, reliability, installation practicality and long-term operational needs.
How can JWF help?
JWF provides a wide range of flow measurement technologies and engineering solutions across multiple industries.
Our flow instrumentation and measurement partners include world-leading instrumentation companies ABB, WIKA, Emerson Flexim, Dresser Actaris, Sensus and Redseal.
From the supply and installation of ultrasonic flow meters and electromagnetic flow meters to commissioning and calibration and providing round-the-clock data access via our cloud solution, Brella, our team helps businesses gain accurate and actionable insight into their processes while improving efficiency and reliability.
Whether you need a permanent installation, a portable survey solution or guidance on selecting the right technology, JWF can help identify the most effective flow measurement solution for any industry.
To learn more about the various flow measurement technologies and engineering solutions JWF offers, click here or get in touch with our team.