Overview

An Inline Type Air Flow Transmitter is a precision instrument specifically designed for installation inside ventilation ducts, HVAC systems, or industrial pipelines to measure the airflow (gas volume flow rate) passing through the duct accurately and in real time.

Its operating principle is based on measuring the air velocity at a specific point inside the duct. By combining the measured air velocity with the user-defined cross-sectional area of the duct, the transmitter calculates the real-time volumetric flow rate using the following formula:

Air Flow = Air Velocity × Duct Cross-sectional Area

Main Types and Configurations

Depending on the installation method and application requirements, inline type air flow transmitters are available in several configurations:

Insertion Type

The sensing probe is inserted into the duct through a mounting opening. This is the most common configuration due to its simple installation and suitability for a wide range of duct sizes.

Averaging Type

To compensate for non-uniform air velocity distribution within the duct, averaging transmitters (such as averaging Pitot tubes or multi-port flow probes) feature multiple sensing ports on both the upstream and downstream sides of the probe. These sensors measure the average air velocity across the duct cross-section, resulting in improved measurement accuracy.

In-Line (Duct Section) Type

In this design, the transmitter is integrated into a dedicated section of ductwork and connected to the ventilation system using flanges. This configuration provides secure installation and high measurement stability but requires sufficient installation space.

Typical Applications

Thanks to their reliability and high measurement accuracy, inline type air flow transmitters are widely used in applications requiring precise airflow monitoring and control.

Building Automation and HVAC

Used for airflow measurement and control in fresh air systems, air conditioning ducts, and ventilation systems to improve energy efficiency and indoor comfort.

Industrial Process Control

Applied in power generation, metallurgy, chemical processing, and other industrial sectors for ventilation, exhaust gas, and flue gas flow measurement.

Critical Environments

Widely used in hospital negative-pressure isolation rooms, laboratories, cleanrooms, and other controlled environments where accurate airflow and pressure management are essential.