 |
 What
are instrumented pig? |
 |
Instrumented pigs (IPIG) are devices
used for inline monitoring the health of operating long distance
buried cross-country pipelines.
|
How
does an instrumented pig travel inside the pipeline? |
|
Instrumented pig travels inside the pipeline
with the propelling force of the fluid (liquid or gas) being
pumped through the pipeline.
|
On
what principle these devices work? |
|
These devices works on the followings
principles:
Magnetic Flux Leakage
The magnets mounted on these devices saturate the pipe wall
with magnetic flux. The magnetic flux leaks at the point of
metal loss on the pipe wall. This change in the magnetic flux
is sensed by sensors.
Ultrasonic Principle
Ultrasonic signals are generated through the pipe wall. Change
in the signal is observed due to change in the wall thickness
of pipe. This change in the ultrasonic signal is sensed by
sensors.
|
How
sensed data is used for defect analysis? |
|
The sensed data is recorded on the onboard
electronics and downloaded after the completion of the run.
The recorded data is analysed with the help of software programme
to know the exact size and location of the defects.
|
How
much length can be inspected in one run? |
|
The length of pipeline to be inspected
in one run mainly depends upon the battery life and data recording
capacity of the system. About 100 Km or more pipeline length
can be inspected in one run.
|
How
Instrumented pig is located during Inspection? |
|
The pig travel is monitored based upon
the data of fluid flow rate in the pipeline. The pig is tracked
during travel at the main pipeline locations like MOV, road
and river crossings etc. The instrument known as pig locator
is used for this purpose.
|
What
type of defects these devices can detect? |
|
Instrumented pig based on MFL principle
can detect metal loss in pipe wall caused due to gouges, dents
and corrosion etc. The pipeline features like sleeves, casing,
tee, valves and weld etc; are also detected by MFL based Pigs.
However devices functioning on the
ultrasonic principle are known to detect the pipe wall and
weld cracks also. The defect detecting capability of tool
depends upon the purpose of the tool for which the same has
been designed.
|
What
type of tool IndianOil has
developed? |
|
IndianOil has developed a tool
based on MFL principle for the inspection of 12-inch diameter
pipeline. |
