Vibration measurements in extreme environments

Client

Turbine manufacturer for energy production.

Challenge

Vibration measurement is an essential step for validating turbine shaft durability. To account for all parameters, measurements are carried out under real-world conditions. In some cases, the measurement is even embedded for continuous application monitoring.

For certain applications, such as the client’s, operating conditions present a real challenge for instrumentation:

• Temperature: cryogenics or high temperature (combustion).
• Pressure (vacuum, high pressure)
• Radioactive environment (nuclear)
• Presence of fluids
• Limited available space

These conditions notably make the use of accelerometers impossible. Another complexity: the application involves rotation.

It is in this context that PM Instrumentation is consulted.

Proposed solution

PM Instrumentation has deployed a solution addressing these extreme constraints across numerous applications in aeronautics, aerospace, and energy. The eddy current displacement sensors from the 19xx series measure, without contact, the distance to a target placed on the rotating shaft. This solution was specifically designed for such applications:

• Operating temperature: 20K to 600°C
• Operation in radioactive environments
• Compatible with fluid use, including corrosive fluids
• Operates under vacuum (space) up to 250 bar

Client benefits

• The solution enables operation under real-world conditions
• No durability limitations, suitable for both validation and continuous use
• Wide bandwidth (up to 50 kHz)
• Analog output signal (voltage or current) easy to acquire
• The sensor is mounted on a fixed support, away from the shaft (several mm). It is not subjected to shaft vibrations, adds no unbalance, and there is no limit on rotation speed
• Possibility to position multiple sensors around the shaft. The electronics enable clock synchronization across different channels for perfect measurement synchronization.