Figure 2 . A visualisation of the difference in the form of a score by machine learning . π www . valve-world . net Valve World August 2023
Emission control
The detection of valve condition by gyro sensors
Problems such as malfunctioning valves or internal leaks in a plant can have a significant impact on the plant and sometimes result in significant losses . To prevent such problems , Kitz developed solutions that can detect valve condition by gyro sensors .
By Isao Nishizawa , KITZ Corporation
Figure 1 . The operation speed has changed .
Case study of anomaly detection by gyro sensors
We collected gyro sensors data from a customer using a valve to control slurry fluid . In this customer ’ s experience , the valve wasn ’ t able to prevent the seat breaking , or in the worst case scenario , the seat completely disappearing . Figure 1 shows an angular velocity at close to open when we first started collecting data in July . After about 4 months , we were able to detect changes in the angular velocity . Operation speed changed from 1.8 seconds in July to 2.2 seconds in December . This change was difficult to see with the naked eye .
Case study of anomaly detection by machine learning
Although we found out that the angular velocities change , it is difficult to compare the angular velocities on a daily basis , and it is also difficult to evaluate them . Therefore , we visualised the difference from the angular velocity in the normal state as a score by machine learning ( see Figure 2 ). The vertical line shows the score value and the horizontal one shows the date . From the graph , we can see that the score changes from October to December . So , when I disassembled the valve in December and inspected it , we found that the seat was damaged . The cause of the ball seat damage is due to the slurry depositing and sticking to the back of the seat and pushing up the seat . In this situation , seat leaks were not yet occurring , so we were able to catch signs of the seat damage in advance . It was also confirmed that the score decreased after performing the maintenance of the seat replacement .
Figure 2 . A visualisation of the difference in the form of a score by machine learning . π www . valve-world . net Valve World August 2023
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