Air and Gas Flow Meters

Technology and Operation of Compressed Air and Gas Flow Meters

Flow measurement determines how much air or gas passes through a pipe over a given period of time. In industrial systems, this information is more than a numerical value: it becomes a control tool for understanding consumption, monitoring process performance, managing a distribution network and identifying opportunities to improve system efficiency.

When monitoring compressed air, flow data provides clearer insight into consumption, distribution and potential network inefficiencies. In gas applications, measurement is essential for process control, volume metering and the management of operating conditions.

Depending on the technology, the meter may provide a local reading, a totalised volume or a signal transmitted to a supervisory system. In turbine meters such as EQZ, TRZ and QA, the gas flow rotates a turbine, generating data proportional to the volume or flow rate. In rotary piston meters such as RABO, volumetric measurement is obtained through mechanical measuring chambers, providing stability and accuracy even under variable operating conditions.

The range also includes flow indicators for air and gas, suitable where a visual flow reading supports day-to-day system control, as well as thermal flow meters, which measure flow in relation to the thermal properties of the fluid.

Types of Flow Meters Available

The Riels range for compressed air and gas measurement includes instruments designed for different requirements. The available technologies make it possible to select the most suitable meter for the type of gas, the measuring range, system configuration and required level of accuracy.

● Turbine gas meters: a well-established solution for measuring gas volume in industrial applications. Among the available models, EQZ is designed for natural gas, methane, butane and propane, with pulse output and configurable measuring ranges. TRZ uses the same radial turbine principle and is suitable for applications requiring fiscal metering, while FMT-Lx extends the range to high flow rates and large-diameter pipes, with MID approval for fiscal metering.

● Gas meters with mechanical totalisers: models such as QA are designed to measure flow and consumption over time for inert and flammable gases, air and natural gas. The mechanical totaliser provides an immediate volume reading, making consumption data readily accessible in industrial and commercial systems.

● Quantometers and rotary piston gas meters: RABO provides stable, accurate volumetric measurement for a range of gases and technical gases. Versions with pulse output, a totaliser and configurations for horizontal or vertical installation make these instruments suitable for networks and systems where measurement continuity and mechanical reliability are essential.

● Air and gas flow indicators: complete the range where immediate, local measurement is required. Their visual flow indication makes them useful for monitoring, regulation and verification of fluid flow in industrial and technical applications.

For a more detailed explanation of how flow measurement works, read our flow measurement guide.

How to Select the Right Meter for Your System

The choice of a gas flow meter or compressed air flow meter depends on how the instrument must integrate with the system. The fluid being measured, flow range, pressure, temperature, pipe diameter and connection type define the technical parameters for identifying the most suitable solution.

Compatible Gases

Depending on the model and operating conditions, the meters can be configured for different types of gas. The range includes instruments for air, natural gas, methane, propane and butane where specified, as well as inert gases and flammable gases when used with a suitable device. Some of our models are also suitable for biogas, exhaust gas, landfill gas, ethylene, carbon monoxide, ethane or technical gases.

Applications for Compressed Air and Gas Flow Meters

Our flow meters are used for monitoring compressed-air consumption, industrial gas distribution, measuring natural gas or methane systems and consumption metering. In manufacturing, technical and commercial environments, they make energy flows easier to understand, supporting process control, internal cost allocation and improved system efficiency.

Certifications and Regulatory Requirements

When selecting a flow meter for compressed air and gas, it is important to verify compliance with the certifications required by the application, including MID, ATEX and PED. MID approval may be required for fiscal consumption metering, while ATEX and PED are relevant in potentially explosive atmospheres, with flammable gases or under specific pressure conditions. Checking the applicable certifications helps identify an instrument that meets the system’s safety, quality and compliance requirements.

Unsure which air and gas flow meter is right for your system? Contact us for technical advice.

Reliability and Accuracy of Riels Compressed Air and Gas Meters

Choosing a flow meter for compressed air and gas means relying on measurement data for an important part of system control. This is why we select instruments engineered to deliver stable readings, long-term accuracy and operational continuity, including in industrial applications where consumption, metered volumes and process conditions must remain consistently under control.

We complement product quality with technical expertise, application consulting and dedicated services: from model selection and the assessment of installation conditions to support for calibration, testing and special configurations. Our experience in process control and industrial automation since 1967, together with compliance with UNI EN ISO 9001:2015, reflects a commitment to accuracy, reliability and continuous improvement. Configure the most suitable meter for your application or contact the Riels technical team to identify the right solution for your system.

FAQ

What is the difference between a flow meter, a flow indicator and a gas meter?

A flow meter is a general term for an instrument that measures the quantity of fluid passing through a pipe. A flow indicator is typically used to display the instantaneous flow rate, often through a local visual reading. A gas meter is designed for volumetric measurement and for totalising consumption over time.

What is the difference between an insertion and an inline flow meter?

An inline meter is installed directly in the pipeline and measures the fluid passing through the instrument body. An insertion meter is introduced into the pipe and may be suitable for certain system configurations, particularly where pipe diameter and installation conditions make this arrangement more appropriate.

Can gas flow meters be used in ATEX zones?

Only when the specific model and its configuration are suitable for use in a potentially explosive atmosphere. For flammable gases or regulated environments, ATEX suitability must be verified against both the instrument and the operating conditions.

Do compressed-air flow meters require maintenance?

Maintenance requirements depend on the technology and model. In general, periodic checks, correct installation and suitable operating conditions help maintain stable measurement performance over time.