Stationary Or "Stuck" Pigs - CDI CD42 Instruction Manual

occurred at that location, and then quickly moving to the next location and repeating the process.
The CD42 easily shows the operator the pig‟s passage at each location.
When an operator sets up the CD42 receiver at a location to await a pig passage, he should orient the
receiving antenna parallel to the pipeline. As the pig approaches the location and then moves away,
it produces a distinctive wave shape on the display. Figure 13 is an example of a typical pig passage
at a speed of approximately 4MPH. Faster pig passages produce the same image, it simply will
have fewer pulses in it.
Figure 13 A Typical Pig Passage Wave Shape on the Receiver's Display
The CD42 receiver has the ability to record up to 99 of these pig passages, including the entire
image, time, date and mile or kilometer marker of the event. To learn more about some of the
CD42-R receiver‟s advanced features, please read the section entitled "Gain Buttons" beginning on
page 16. For a more thorough discussion of tracking, interpreting and recording the passages of
pigs, please refer to "Chapter 6 - Tracking a Moving Pig" beginning on page 53.

Stationary or "Stuck" Pigs

Although being able to witness pig passages as shown above is a very valuable feature that allows
you to monitor the progress of a pig through a pipeline, the CD42‟s ability to locate a stationary or
"stuck" pig is perhaps its most important feature. If you‟ve rented the CD42-K1 system, then you
are probably concerned that you are about to run a pig through a pipeline in which it might get stuck
at some point.
The best way to ensure the minimum amount of work in the event that a pig sticks in the pipeline is
for the operator to track the pig‟s progress through the pipeline by leapfrogging. If the pig does
stick, then the operator will know when the pig does not pass by his location. He must then
backtrack by walking the pipeline to his last known-good passage location while looking for
transmitter pulses using the CD42-R receiver. For this reason, it is best for the operator to locate his
leapfrogging points on the pipeline as close to one another as possible. This will minimize any
distance that the operator will have to walk.
Note: It is important for the operators of the equipment to determine the flow rate of their
pipeline, how fast the pig will be moving, and if they will be able to get from one
leapfrogging point to the next with a few minutes of setup time to spare.
CD42 Pipeline Pig Location & Tracking System
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