For a long time, there were only two options in preventive maintenance: Either users relied on unconventional diagnostic methods such as the hearing test with a screwdriver or the soap suds test, or they invested in expensive devices for infrared or vibration diagnostics. An alternative is ultrasound-based monitoring. The so-called 'ultrasonic spy' from the USA is even used by NASA, for example, as it detects malfunctions in the early stages at a manageable cost - regardless of whether electronic components or the mechanics are affected, whether it is a leakage of gas, compressed air or in the hydraulic system. A new app for Android mobile devices also increases the effectiveness of the solution by recording ultrasonic operating noises from engine mounts and gearboxes, for example, and uploading them to the 'InCTRL Cloud' for evaluation. This makes it possible to carry out repairs immediately and check their effectiveness directly on site instead of having to transfer the data and evaluate it in the office.

Unexpected maintenance work due to defective components can lead to an increased need for spare parts, dissatisfied customers and a great deal of additional work and costs. How can ultrasound be used to identify the potential causes of malfunctions?

When material particles rub against each other - for example, escaping compressed air against ambient air, bearing against shaft, electrical energy against insulator - a noise is generated in the ultrasonic range. The 'ultrasonic spy' uses a specially developed ultrasonic microphone to convert the characteristic noises of the defects into sounds that are easily audible and even understandable to the human ear.

The use of ultrasonic technology is particularly suitable for moving mechanical components such as bearings, gears, motors or compressors. Faulty components, gas leaks, defective seals or mechanical damage can be identified using characteristic noises that these damages produce at a frequency of 40 kHz. The noises are caused by friction, shocks, turbulence and electrical discharges. These are not simply diffuse noises - rather, the respective sound quality makes it clear which defect is present. The probe of the ultrasonic device is so sensitive that it registers leaks within a radius of 30 meters. The closer the inspector gets to the leak, the more the pointer deflects and the louder the sound. The size and type of leak can be determined by the pitch and height of the sound.

App improves maintenance processes

Even if friction occurs naturally in some cases, for example, it must not become too great - in the worst case, there is a risk of production downtime. Users should therefore ensure that the general conditions remain as constant as possible so that fluctuations in the measured values are not due to a different speed or load.

A monthly check of the test points for wear and the condition of the lubrication is ideal.

© Richard Chambers

If this is taken into account, changes can be detected earlier, faster and more easily with the help of the ultrasound solution than with infrared or vibration analysis. The ultrasound is taken directly from the handheld device and uploaded via smartphone to a cloud-based program for history comparison and analysis.

Previously, the mechanics were monitored using a pocket computer. In order to evaluate the noise and observe the wear, the measurement results had to be imported, saved and evaluated on the PC in the office. This step is now no longer necessary: the InCTRL app fits seamlessly into the existing maintenance processes as a key component of the monitoring solution and helps to improve them. In addition, archiving in the cloud facilitates communication and integration throughout the company.

To take a measurement, it is necessary to check in advance whether the receiver is set to match the test point setting. The recording is saved as a file so that the upload - if neither Wi-Fi nor a fast mobile data connection is available - can be carried out automatically at the next opportunity. Once the process has been successfully completed, a graph appears on the display that compares the recording information with the previously created audio tracks and previously set limits. In this way, the user knows how to classify the new measurement even before they return to the office. If the critical threshold is exceeded, the program sends an automatic e-mail notification to the person responsible. After appropriate countermeasures, such as a repair or the installation of a replacement part, the success should be checked immediately with another measurement.

System enhancement with Bluetooth

The "UltrasonicSpion" - consisting of an ultrasonic generator, probe and soundproof headphones - reliably detects leaks even in production areas with noisy surroundings.

© Richard Chambers

With the optional use of Bluetooth as a system add-on, the connection from the 'spy' to the headphones or tablet can also be established wirelessly. The maximum distance is 10 m. For example, instead of just listening to the master craftsman's explanations during training, trainees can also directly understand what is being said, or two colleagues can carry out the examination together, which was difficult or even impossible in many cases with a cable connection. The current headphones also offer the advantage that they not only dampen the noise in the environment by around 25 dB like the previous models, but also absorb external noise almost completely, as they work with 'white sound'. This means that even quieter sounds and finer nuances can be perceived in order to detect even very small leaks.

The rights to the data

The InCTRL app for Android devices can be downloaded from the Google Play Store and used as a subscription. Installation is simple: when ordering, the user receives a password for the download. A suitable cable for connecting the 'spy' to the smartphone will be sent on request. Different versions of the software are available depending on how many test points are to be measured and how many users are working with the system. The app can be accessed directly via the standard web browser and is secured by a personal login. The locations and test points can be set up and updated at any time via the account. The rights to the data remain with the customer.

No IT support, installation of additional software or configuration of a database is required to use the functions. This eliminates the need for IT integration on the user side and reduces hardware costs. Archiving in the cloud is particularly interesting in cases where several machines need to be checked or different people are entrusted with monitoring. Companies with multiple locations can also send reports that are relevant to the supervisory and responsibility levels to the relevant departments.

Author: Richard Chambers is Managing Director of Richard Chambers in Heimstetten.