FLIR Acoustic Imaging Cameras are advanced devices designed to detect, visualise, and analyse sound emissions from various sources. They utilise arrays of microphones to capture sound waves, which are then processed to create visual representations of the acoustic information. This technology enables users to pinpoint the exact location of sound sources (e.g. compressed air, gas, and vacuum leaks, as well as partial discharges in high-voltage systems), facilitating efficient diagnostics and maintenance.

Measurement and Functionality

Here's a breakdown of what they detect and the measurement process:

Microphone Array: These imagers use an array of multiple highly sensitive microphones. The array is strategically designed to capture sound waves from different directions.
Sound Waves (in the ultrasonic and audible range): They detect pressure variations in the air caused by sound sources. While human hearing is limited to the audible range (roughly 20 Hz to 20 kHz), these cameras often excel in the ultrasonic range (above 20 kHz), where many industrial faults emit sound. Acoustic Image Generation: The processed sound data is converted into an acoustic image. This image is typically displayed as a colour map superimposed on a live visual image captured by an integrated visible light camera. The colour map visually represents sound intensity and location. For instance, a compressed air leak might appear as a bright, localised colour spot overlaid on a pipe or fitting image.
Sound Frequency: Many advanced models can analyse the frequency content of the detected sounds. Sound sources (like leaks vs. electrical discharge) often have characteristic frequency signatures. Frequency analysis helps classify and identify the source of the sound.

Applications

FLIR Acoustic Imaging Cameras and Imagers are used across a wide range of industries and applications for preventative maintenance, troubleshooting, and safety:

Compressed Air Leak Detection: Acoustic imagers quickly locate these leaks, even in noisy environments, allowing for efficient repairs and energy savings in manufacturing plants, processing facilities, etc. The Si124-LD Plus is designed specifically for leak detection applications.
Gas Leak Detection: They can quickly scan pipelines, valves, and fittings in oil and gas, chemical processing, and utilities.
Electrical Fault Detection (Partial Discharge, Corona Discharge, Arcing): Electrical faults like partial discharge and corona discharge emit ultrasonic sounds before they lead to major failures (like arcs or equipment breakdown). Acoustic imagers can detect these sounds from a safe distance, allowing for early identification and preventative maintenance in substations, switchgear, transformers, and overhead power lines. The Si2-PD is specifically designed for detecting partial discharge.
Mechanical Fault Detection (Bearing and Gearbox Issues): Failing bearings and gearboxes often produce unique ultrasonic sound signatures before they become visually or audibly obvious. Acoustic imagers can monitor rotating equipment in factories, wind turbines, and machinery, identifying potential failures early on.
Vacuum Leak Detection: In industries like pharmaceuticals, food processing, and semiconductor manufacturing, where vacuum systems are critical, acoustic imagers can locate vacuum leaks, ensuring process integrity and efficiency.
Building Diagnostics: Detecting air leaks in building envelopes, identifying sources of drafts and energy loss, and improving building energy efficiency.

In general, they can be used to pinpoint sources of unwanted noise in various environments, aiding in noise reduction and occupational safety efforts.