Industrial Utility Efficiency

Ultrasonic Leak Detectors Help Dairy Producer Optimize Compressed Air System

A modern dairy without compressed air is nowadays no longer imaginable, and it is used primarily for driving control units and machinery. Approximately 60 percent of the compressed air generated is used for packaging lines. However, compressed air is one of the most expensive energy sources in dairies. Even in carefully maintained compressed air systems, about 20 percent of the generated energy is lost through leaks. In particular, vacuum leakages in separators result in high energy losses. A small leak can cost up to several thousands of Euros a year.

DMK Group is Germany’s largest dairy company with approximately 7,400 employees. They have more than 8,900 milk producers, and process the milk at 26 sites. Eight facilities are available for the production of infant formula, ice cream and health products. Overall, the company delivers 6.8 billion kilos of milk annually.

The goal of the DMK Group is to eliminate 50 percent of the leaks within the next two years. For that reason, a leak management system was established. The leakages are found with an ultrasonic testing device of the SONAPHONE family. Depending on repair costs and amount of losses, they will be repaired.

More and more companies rely on ultrasonic testing devices, which detect leaks at plants easily and quickly. Around 30 percent of the energy used for compressed air systems is lost through leakages. The leaks typically occur at couplings, valves or gates, as well as on faulty hoses, screw and flange connections, or corroded pipe work. If these leakages remain undetected, even the best compressed air control can be of no further help. Compressors have to compensate permanent pressure loss in order to provide compressed air. They run for longer, need more energy, and wear out faster. The result is higher costs.

The regular detection and rectification of leakages, which are often only millimeters in size, contributes to huge cost savings and improvement in energy efficiency in dairy companies.


Maintenance with Ultrasound

Using SONAPHONE technology by SONOTEC, anybody is able to locate leakages and seal failures in compressed air, gas and vacuum systems quickly and easily. The ultrasonic devices detect sound waves, which are in a frequency range beyond that which human beings are capable of perceiving. The SONAPHONE renders the noises generated by escaping compressed air as optical values on the display and audible signals via loudspeaker or headphones.

In this business area, the SONOTEC product range includes the reasonably priced entry-level model, multifunction devices with a backlit display, data logger and USB interface, and, with the SONAPHONE E, an ultrasonic detection device for use in areas with high risk of explosion. The advantage of the ultrasound method lies in how simple it is to handle. The point that has been located is marked and then repaired.


Sonotec Product Family

SONOTEC offers a wide range of handy SONAPHONE devices.


Checking Valves and Steam Traps

In addition to the fast, reliable location of compressed air and gas leaks, the ultrasonic testing devices of the SONAPHONE series are used in dairies for the inspection of steam traps and valves.

"With a special structure-borne probe and a surface temperature sensor, valves and steam traps can be easily and thoroughly inspected," explained Christoph Schimmel, sales manager for maintenance devices at SONOTEC. “The structure-borne probe enables experts to carry out noise measurements and follow them acoustically through the headphones. Based on the noise generation, maintenance technicians can assess the condition of a valve or a steam trap. Measurements of steam traps can be made with the ultrasound probe at predefined points and lead to fast and safe results.”


Multifunctional Device for Diverse Applications

The handheld ultrasonic devices in the SONAPHONE range are also suitable for tightness testing of various systems, wear control on rotating machinery, and providing evidence of electrical partial discharges where there is insulation damage. The SONAPHONE makes a significant contribution to energy savinsg and gives indications where preventive maintenance work should be carried out to avoid greater damage and ensure machine availability in many food manufacturers.


Sonotec Sonophone

The acoustic horn for airborne probe L 50 enables leak detection up to 8 meters.


A multitude of optional attachments and probes enable a further extension of the SONAPHONE testing devices' areas of application. They can, for instance, be fitted with the Sonospot parabolic probe to allow measurements to be carried out at locations which are difficult to access or a long way away. The light, user-friendly probe has a particularly high range and detects leaks and noises over distances up to 20 meters.


Training in Germany's Largest Dairy Company

Since the various applications of ultrasonic testing devices are often unknown, SONOTEC offers training for technicians and engineers interested in maintenance and energy management.

"In our training, we show the potential of ultrasonic testing devices for companies and introduce the participants to different methods of ultrasonic testing," explaied Schimmel.

Germany's largest dairy company, DMK Deutsches Milchkontor GmbH, took advantage of this offer. Energy officers and technicians were trained in the use of the innovative ultrasonic devices at the location in Holdorf (Lower Saxony). The maintenance department of DMK has integrated leak detection into their workflow. SONOTEC supported DMK with training in the use of the ultrasonic devices and the software.

Compressed air plays a key role at all locations of the DMK Group and is a major cost factor. Therefore, in each location, an energy officer works on optimizing the compressed air system. Leak detection is carried out in all areas sequentially and continuously. After all areas of the plant have been tested, the cycle begins again.

"Our goal is to reduce significantly the leakage rate of our compressed air systems by using the SONAPHONE technology," explained Yvonne Gödeker, energy officer at the site in Georgsmarienhütte.

The easy handling of the device has impressed the energy officer: "Even after one-day training we could find leaks with the SONAPHONE and assess the state of steam traps."

Flexible, efficient and easy-to-use, SONOTEC’s innovative testing technology will become part of the basic equipment of the maintenance technicians in all subsidiaries of DMK GROUP.



Founded in 1991, SONOTEC GmbH is currently a leading specialist in ultrasonic measurement technology solutions. With more than 120 employees, the technology company based in Halle (Saale) in the heart of Germany develops and manufactures customer-specific ultrasonic transducers and sensors, as well as testing equipment and measuring technology solutions for a wide variety of industries. These range from medical technology and the chemical and pharmaceutical industries to engineering and plant construction and non-destructive testing.


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