Ultrasonic Leak Detectors

Ultrasonic leak detectors are instruments that identify the high-frequency sound waves, typically in the 35kHz to 45kHz range, produced by leaks in pressurised or vacuum systems. Because the detection method is non-invasive, systems can remain live and operational during inspection, with no shutdown or physical access to the leak source required. Most units combine an audible alert through headphones with an LED bargraph or visual display, giving maintenance personnel immediate feedback on both the presence and relative severity of a leak.

Adjustable sensitivity and automatic background noise compensation allow the instrument to be tuned to the specific environment. RS Australia stocks a comprehensive range of ultrasonic leak detection equipment from trusted brands including RS PRO, FLIR and Fluke, covering handheld detectors, acoustic imaging cameras and contact probe kits for compressed air, refrigerant, water, steam and vacuum applications.

How Does Ultrasonic Leak Detection Work?

A leak in a pressurised or vacuum system generates turbulent gas flow at the point of escape, producing broadband noise that includes frequencies well above the range of human hearing. A piezoelectric sensor in the detector captures these high-frequency waves and the instrument heterodynes the signal, shifting it down into the audible range so the operator can hear it through headphones. As the operator sweeps the ultrasonic leak detector across the area being inspected, signal strength increases as the probe approaches the leak source, allowing precise localisation even in noisy industrial environments.

For structure-borne applications, a contact probe detects ultrasound travelling through solid materials, enabling identification of internal valve leakthrough and steam trap failures without opening the system. Where the inspection covers large or elevated areas, a parabolic reflector accessory can extend the airborne detection range significantly, focusing distant signals onto the sensor.

Types of Ultrasonic Leak Detectors

Ultrasonic leak detectors are available in several formats, each suited to a different inspection task, working environment or level of measurement detail required.

• Handheld Ultrasonic Detectors: Handheld units are the most widely used format for general maintenance and inspection work. A single-sensor wand detects airborne ultrasound in the 38 to 42 kHz range, with sensitivity sufficient to locate leaks through orifices as small as 0.1 mm. Headphones translate the ultrasonic signal into an audible tone, while an LED bargraph provides a simultaneous visual indication of signal strength. These units are compact, battery-operated and suited to routine compressed air surveys, refrigerant checks and vacuum system inspections across a wide range of industrial settings.
• Ultrasonic Acoustic Imaging Cameras: Acoustic imaging cameras use an array of microphones to produce a visual sound map overlaid on a live camera image, pinpointing the leak source with precision across distance. This format is particularly well suited to large plant areas, elevated pipework and complex systems where a handheld wand would require the operator to work in close proximity to every component. The visual overlay allows multiple leak sources to be identified and prioritised in a single pass, making these cameras a highly efficient tool for planned maintenance and energy audit programmes.
• Contact Probe and Structure-Borne Detectors: Contact probe detectors are designed to pick up ultrasound transmitted through solid materials rather than through the air. The probe is applied directly to pipe walls, valve bodies and bearing housings, allowing the operator to detect internal leakthrough in steam traps and valves, assess bearing condition and identify leaks in pressurised lines where airborne detection is not practical. This format complements handheld airborne detection for a more complete inspection capability.

Benefits and Features of Ultrasonic Leak Detectors

Ultrasonic leak detectors offer practical advantages over traditional detection methods such as soap-bubble testing or tracer gas, particularly in live industrial environments where speed and minimal disruption are priorities.

• Non-Invasive Operation: No system shutdown or physical access to the leak point is required, making ultrasonic leak detectors safe to use in live, pressurised environments without interrupting production or process continuity.
• Time-Saving: Audible and visual feedback is instantaneous, reducing time-to-locate compared to manual methods. Quantifiable signal strength also allows maintenance teams to rank leaks by severity and prioritise repairs accordingly, directing resources where the energy or material loss is greatest.
• Versatile: Ultrasonic leak detection equipment works on any pressurised gas or vacuum system regardless of the gas type involved, covering compressed air, refrigerants, steam, hydraulic fluid and water in a single instrument. Many units are rated IP54 or above, supporting use in wet or dusty outdoor environments.

Applications of Ultrasonic Leak Detectors in Australia

Ultrasonic leak detectors are deployed across a wide range of industries wherever pressurised or vacuum systems require regular inspection and maintenance.

• Compressed Air Systems: Compressed air leaks are among the most significant sources of energy waste in Australian industrial facilities, with undetected losses capable of consuming a substantial proportion of a compressor's total output. Ultrasonic detectors allow maintenance teams to survey pipes, fittings, couplings and valve bodies under live pressure, identifying and logging leak points for scheduled repair without interrupting production.
• Refrigeration and HVAC: Ultrasonic detection equipment operates independently of the gas type involved, picking up the turbulence produced by escaping refrigerant regardless of whether the system uses R410A, R134a, R32, R1234yf or any other refrigerant. This makes it a practical complement to gas-specific electronic detectors for HVAC technicians servicing a mixed equipment base across commercial and industrial sites.
• Water and Hydraulic Systems: Pressurised water main leaks, hydraulic line failures and leaking valve seals can all be located using ultrasonic detectors, including in buried or enclosed pipework where visual inspection is not possible. Contact probes allow the operator to scan through pipe walls and valve bodies to identify internal leakthrough without isolating the system.
• Steam Systems: Steam trap failures and leaking steam valves waste significant energy and accelerate equipment wear. Ultrasonic detection identifies both failed-open steam traps, which pass live steam continuously, and failed-closed traps, which block condensate return, allowing targeted maintenance rather than blanket replacement programmes.
• Vacuum Systems: Micro-leaks at fittings, seals and flanges in vacuum systems can be difficult to locate using conventional methods. Ultrasonic detectors identify the turbulence generated at the leak point even when the pressure differential is small, supporting leak integrity verification on process vacuum lines, laboratory equipment and industrial vacuum chambers.
• Automotive: In automotive workshops and manufacturing facilities, ultrasonic detectors locate leaks in cooling systems, air conditioning circuits, exhaust systems and engine vacuum lines. The non-invasive approach allows components to be tested under operating conditions, reducing diagnostic time and avoiding the need to dismantle assemblies for visual inspection.

Buy Ultrasonic Leak Detectors Online from RS Australia

RS Australia is a trusted supplier of ultrasonic leak detectors for maintenance teams, HVAC technicians and plant engineers, stocking instruments from RS PRO, FLIR, and Fluke. Our range covers handheld detectors, ultrasonic acoustic imaging cameras and contact probe kits suited to compressed air surveys, refrigerant inspection, steam trap testing, and vacuum system verification across industrial and commercial applications.

Complementary products including gas detectors and analysers, vibration meters, and pressure gauges are also available, supporting a complete condition monitoring and leak detection setup from a single supplier. Browse the full range of ultrasonic leak detectors online and order with fast, Australia-wide delivery. For more details on delivery services and fees, please refer to our Delivery page.