New Lightweight Pig Passage Search And Track Device

Special to Pipeline & Gas Journal
February 2012, Vol. 239 No. 2

The L22M in convenient carry pouch.

Technology moves on but instruments to search, monitor, or record the passage of a pipeline pig have not kept up and are often very short on features and high on price. Some devices simply provide a means to view the strength of a 22-Hz signal and, perhaps, log a low-grade pig passage time.

In most cases the operator has to be present to view the display, and any logged time data can’t be used as AGM time reference. Most of these receivers cannot do magnetic detection at all.

There are many other real-world situations in which such simple devices are inadequate; they're heavy, bulky, and are often cluttered with wired external sensors and headphones.

All these shortcomings are overcome by the new L22M Search and Track Receiver which can remotely monitor and record the passage of pigs that use an ELF transmitter (22 Hz) or MFL magnets (MAG). In many cases the unit will even record the passage of a metallic pig using only its intrinsic low level magnetic field. As a lightweight (<3 lbs.) hand-held device, it can also be used to locate a pig stuck in the pipeline, using its ELF or magnetic sensor and its graphics display features.

The unit contains a GPS receiver and uses Bluetooth® communication. As a bonus, it costs about half as much as the older, outdated search receivers.

It can be set on the pipeline right-of-way and operated in one of four modes to detect and record (into internal memory), view potential pig passage signals, wirelessly notify the operator of the pig passage, or simply search for a stuck pig.

AGM Recording Mode
L22M continuously records both ELF and MAG channels with GPS timing accuracy and shows a list of events above threshold on its display. This mode allows unattended recording in multiple sessions for up to 570+ hours in multiple recordings. Signal traces from events on this list can be easily viewed on the same graphics display immediately after a pig passage. All data are retained in memory for later analysis. This mode requires only the L22M - no laptop computer or other equipment is needed. All data are available for later download to a PC via the Bluetooth® link for viewing and analysis (PC software included).

RTPT_Image2.jpg
Real-Time Pig-Tracking Program shows ELF and Magnetic signal.

Real Time Pig Tracking (RTPT)

Sit in the comfort of your truck while waiting for the pig. Most pig trackers use a PC laptop for GPS guidance; this can also be used to connect the L22M Search and Track by Bluetooth® to view both the MAG and ELF signals in real time while recording the data to the PC hard disk. Signals above user-set thresholds are tagged along with GPS precision timing marks.

All data are available for later review using a well-developed set of user-friendly file management features.

Both AGM recording and RTPT modes produce data at full AGM precision with GPS timing accuracy and can be used for time correlation as AGM reference points in ILI tool data.

Search For Pig
The search for pig mode feature can be useful in locating a “stationary” or stuck pig. Walking the right-of-way (in ELF or MAG mode) using a Bluetooth® earphone to provide audible alerts for above-threshold signals frees the operator from having to pay rapt attention to the display screen. The display is quite useful for precise pig location once the operator has “audibly” found a suspicious area.