PHOTO #4 Removed tube sample

NOTE: Failure in tube
PHOTO #4
Bottom Half - Note Minimal Corrosion
Liquid
PHOTO #5 Severe groove depth adjacent
to edge of support

PHOTO #6

PHOTO #7

PHOTO #8

PHOTO #5
Top Half - Note Corrosion

PHOTO #6
Bottom Half - Note Minimal Corrosion

PHOTO #7 Cross Section
Tube split to show top & bottom
-
Left & right sides show minimal corrosion. Liquid covered.
-
Inner left & right (top circumference of tube) show heavy corrosion. Liquid/Vapor.

PHOTO #8
Top Half - Note Corrosion

Unexpected Tube Failure in
HDS Stripper OVHD Air Cooler
chronicle companion images

PHOTO #2

NOTE: Close up of Failure
PHOTO #1
Top half of tube looking at failure
PHOTO #3
Top Half of Tubing - Note Corrosion
Liquid/Vapor


PDF Version link provided

A specific operating range, optimized phase spread, called Frequency prime (f90), occurring where there's a phase difference from the shallow I.D. to shallow O.D. defects of 90° (aka base frequency). Additional frequencies are selected for mixing, landmarking (supports), flux density considerations, etc. Minimum base frequency = 4.8. Maximum base frequency 2.1 x f90 = 10. f90 = The frequency which generates a 90° phase separation between a shallow inside and a shallow outside originated defect.

The ASME Section V - Article VIII - Mandatory Appendix VIII, states that the operating frequency has to be between the minimum and maximum base frequency as determined by the equations noted on slide 1.

PDF Version link provided