Automated Ultrasonic Generating Bank (near Drum) Inspection System
Tube Thinning / Corrosion Survey

Preferred System:

NIP -  (Near Drum Inspection Probes)

for accurately locating and sizing areas of thinning between 0" and 8" past the drum or tubesheet

The drawing below depicts the area where corrosion or tube thinning is usually found at the near drum level in the generating bank section of a boiler.

INDUSTRY PROBLEM - TUBE THINNING

Tube thinning near the drum in boiler generating bank tubes has been found in

•  Chemical Recovery Boilers in Pulp and Paper Mills,

•  Power Boilers in Fossil Fuel Plants, and

•  Wood Waste Boilers in Steam Plants.

This tube thinning and wastage problem can occur in both the lower and upper drum levels. If left undetected, there is a potential for tube failures. Such an outage would impact on the plant's efficiency and possible losses in revenue. Thinning is caused by a number of agents such as chemical corrosion, soot blower erosion, particulate erosion and steam cutting.

The figure above is a computer B & C-scan displays of a tube (unrolled) with the accompanying end and side profiles (B-scans). The color-codes chosen in the C-scan varies from red (thinnest) to dark blue (thickest).

The figure above is a computer display of B-scans of a tube. The top graph shows all the scans of the tube and the bottom graph shows the single scan where the lowest reading was found. The lowest reading is located in the box on the top right corner of each graph.

Our inspection system does not require the drum or tubes to be totally flooded. Only 1 liter of water per tube, just enough for the inspection, is needed. This enables welding and other maintenance work to proceed in other areas of the boiler.
Stasuk Testing has performed over a hundred generating bank (near drum) tube inspections since 1989.

For further information, contact
Stasuk Testing & Inspection Ltd
8955 Fraserwood Court
Burnaby,
British Columbia V5J 5H7,
Canada
Tel: 604-420-4433 Fax: 604-420-2685