The Teletest Focus+™ has been identified as the optimal Guided Wave Testing instrument for pipe inspection, and with ever-evolving capabilities it continues to perform under extreme conditions to provide actionable data before the next outage.
Guided Wave Testing (GWT) performed by the Focus+ is a proven technique for screening in-service pipelines for degradation such as corrosion. One of the key advantages of using this inspection technique is that testing can be carried out without taking the pipeline offline. However, the current maximum surface temperature for Focus+ equipment had been limited to 120° Celsius (248° F), and while this is acceptable for most process pipelines and transmission lines, there was an increasing demand from inspection companies and end users to inspect at higher temperatures. The time efficiency is obvious for inspecting in-service pipelines rather than having to wait for the next scheduled outage. In addition, knowing pipeline conditions prior to an outage enables proper planning for any potential action required, minimizing delays.
All materials used to manufacture the transducers, modules and collar were reviewed, which lead to a concept that is easily implemented by current Focus+ operators. The transducers were significantly redesigned without changing the size or shape, the module materials were replaced with high temperature plastics and the collar didn’t require rework, but a purpose-built insulator was produced for heat protection. This intelligent combination of design, material selection and insulation enhanced the Focus+’s operating temperature capability to 240° Celsius (464° F).
Prior to release, extensive testing was performed on all high temperature components including cyclic temperature testing and cooling cycles. Post-test analysis showed no evidence of heat damage to the equipment nor deterioration of Signal-to-Noise Ratios (SNR) in collected data when compared to tests performed at ambient temperatures.
The high temperature system was field tested by a Focus+ operator based in North America who successfully operated the system at an astounding 350° Celsius (662° F), keeping the inspection tool on the pipe for approximately five minutes at a time and allowing it to thoroughly cool between locations. This demonstrated that the Focus+ works reliably at extreme temperatures, giving further confidence in the design approach taken. At these temperatures, PZT crystals of the transducer materials approach the Curie temperature which can potentially reduce equipment life, but no issues were found with the procedure implemented in the numerous field trial locations.