Buckle Detection by buckle Detector

During pipelay, the buckle detector may be required for continuous buckle detection. If buckle is detected, the pipeline will be recovered for immediate pipeline replacement.  The buckle detector used is illustrated in the figure below:

Buckle Detector Design:

The buckle detector consists of simple metal structure and the buckle detecting gauging plate.

The diameter of buckle detector gauging plate can be taken as 95% of the pipeline internal diameter (ID), alternatively, it can be calculated in accordance with DNV 1981 Section 8.3.5 as shown below:

d = D – 2t – S

Where,

d = diameter of detector;

 D = nominal outer diameter of pipe;

t = nominal wall thickness of pipe;

S = 0.01D + 0.4t +5L;

L = 20% of t, max. 5 mm.

Buckle Detector Installation: 

Step 1: buckle detector design and setting up;

Step 2: The buckle detector is brought to the firing line where the pipe sections are joined together;

Step 3: The buckle detector is inserted into the pipeline;

Step 4: The required length of cable is attached to the buckle detector (typically, the buckle detector is placed at least 20 m to 30 m (depends on water depth and individual project requirement) downstream of pipeline touchdown point);

Step 5: The buckle detector is pushed to the designated location by ‘blower’;

Step 6: Once the buckle detector reached its designated location, the cable end located onboard is tied to the internal clamp which is used to align two pipe joints, hence, the buckle detector will be pulled continuously once every pipe joint is installed and the barge moves forward.

 References:

1. DNV 1981, Rules for Submarine Pipeline Systems, 1981
2. http://grabcad.com/library/buckle-detector