Hearing is believing

The new Acoustic Expert system facilitates plant monitoring and maintenance work

Designed on a bionic basis, Acoustic Expert is capable of continuously monitoring all plant equipment and components that emit a specific sound spectrum. Plant noise is generated, for example, by electric arc furnaces, the nozzles of torch-cutting machines in continuous casting plants, motors, drives, switching relays and valve stations.

Whereas people find it difficult to detect gradual wear, Acoustic Expert makes this possible through long-term analyses of emitted sound. The system employs an industrial microphone, a monitoring system and an evaluation system.

First application

Acoustic Expert was put to the test for the first time ever in the dedusting system of a secondary metallurgical plant. In this application example, Acoustic Expert monitors the sound caused by the cleaning valves of a pulse-jet bag-filter plant. The profile of each cleaning pulse is recorded in 500 ms long intervals and evaluated immediately afterwards. Audio data is recorded for analysis only and subsequently deleted after processing. Furthermore, Acoustic Expert does not identify human voices. Following data evaluation, the results are visualized in the customer’s HMI (human-machine interface).

Visualization of performance of three different valves
Acoustic Expert integrated within a cloud-service topology

Example of acoustic monitoring and evaluation results

The condition of three pulse-jet bag-filter valves that were sound-monitored with Acoustic Expert is depicted in Figures 2a to 2c. In the first case, the valve is working within an acceptable range, while the center picture shows a decreasing performance trend suggesting gradual wear on the valve membrane. Gradual equipment wear is particularly difficult to detect and in some cases it is discovered too late – namely once the problem becomes evident. With the online Acoustic Expert monitoring system, such wear can be detected earlier through historic trend analyses and interpretation. The third screenshot shows a valve operating at only 40% of its performance capability.

System flexibility

In combination with an online connection, it is also possible to utilize Acoustic Expert as a cloud-based service. In this case, the system can be separated from the local IT network to enable a fully stand-alone monitoring solution. All in all, the system increases the plant-information level and contributes to increased plant productivity through the avoidance of equipment failure (Figure 3).

Success story

Acoustic Expert was installed and put into operation in a secondary dedusting plant of voestalpine Stahl in Linz, Austria, in January 2016. The sound spectrum emitted by the pulse-jet valves during cleaning of the bag filter is analyzed, and any deviation from normal plant operation is detected by the acoustic system. Condition- based maintenance instructions are submitted to maintenance personnel on mobile devices. The Acoustic Expert system implemented at voestalpine was installed in one day without any plant stoppages, optimized in just two days, and brought into operation two months before the scheduled date.

Cloud-based services

Primetals Technologies has recently developed a new cloud-based data-monitoring and evaluation system. With this system, monitoring information from a steel plant can be merged within a single database and analyzed off-site. Advanced calculation algorithms are applied to provide detailed fault information on the basis of root-cause analyses. The results are made available to maintenance or management personnel with an intuitive app, which can be installed on mobile devices such as tablets and smartphones (Figure 4). Historical trend analyses improve the predictability and scheduling of maintenance requirements.

On-site monitoring equipment, which typically includes a server and the associated hardware components, can be minimized. Only a simple machine-to-machine (M2M) communication module with an interface to the customer’s plant is required. Raw measurement data is sent to the cloud for analysis, and equipment investment costs can be notably reduced. Another highlight is that system updates and revisions can be carried out remotely without the need for local personnel or hardware modifications.

Acoustic Expert is the first monitoring system from Primetals Technologies to be integrated within a cloud-based service environment.