CORROSION MONITORING

Waikura CLOSE INTERVAL SURVEY DATA RECORDER

The Line-Trek Close Interval Survey Recorder is a time-based instrument designed for carrying out close interval surveys along underground pipelines. It measure voltages at pre-determined intervals along the pipeline, to local ground, using CuCuSo4 half-cells mounted on the end of a ‘ski pole’ style walking stick. The surveyor has two ski poles wired in parallel.

Connection to the pipe is maintained by trailing a thin copper wire dispensed from a special device, which also measures the length of wire dispensed. A pulse is generated at predetermined intervals (e.g. 1”) and sent to the data recorder. The recorder uses these pulses to measure distance along the pipe.

For the purpose of a survey the CP current supply to the pipe is often interrupted (i.e. turned on & off continuously, typically over a 1 - 10 second cycle). This injects a test pattern onto the pipe, which the recorder detects and automatically synchronises to. In this mode recordings of the on (average ON) & the off (Instantaneous OFF) potentials from the pattern are taken.

The recorder incorporates a graphics display and keyboard that the operator uses to interact with the instrument. The graphics screen displays oscilloscope & chart recorder style pictures of the electrical signal and the data being recorded. The keyboard allows the operator to enter comments, which are recorded, into the data. As both hands are required for use of the ‘Ski Pole’ type probes, the ingress protection IPS65 rated ABS package is carried in a harness around the operator’s neck. It is then easily visible in front whilst walking without having to hold it in the hands.

Features:

Synchronisation

Synchronisation to an interruption cycle is achieved within 2 cycles and is possible even when the interruption signal is very weak. Manual synchronisation is also possible.
Once established the recorder tracks synchronisation along the pipe. A ‘dead reckoning’ mechanism is used so that synchronisation can be maintained during periods of up to 1 hour where there is no interruption signal.

Programming and Display

At the start of every log the following information will be entered by the operator and stored in the log file: File name, Pipe name, Conditions, Temperature, Geological and Environmental conditions, Direction, Survey Type, Date and Time.

PC Software

A Windows application is used to handle data retrieval, data analysis and data manipulation. PC to recorder connection is via RS232 serial cable. Once safely uploaded the log files may be deleted from the instrument memory and free up its storage capacity prior to returning to the field for further surveys.

Data Manipulation after it has been collected is available to accommodate any glitches or breaks in the data. There are a number of reasons why this may occur: e.g. Walking with a broken wire, Climbing fences with the poles off the ground, Hitting rocks, Accidentally recording across roads, Even hitting cow paddies gives bad readings.

Other forms of data manipulation are available such as, reversal of log data so that survey data can be presented in whatever direction required, regardless of actual survey direction. Also merging of multiple files from different sections of the pipe into a single file (individual files are retained as originals for referencing).

During a survey any readings below 850mv are reported (either on or off volts). The PC software reports the total number of readings below 850mv and also the percentage of the total graph that is below 850mv.


Specifications:

Designed and manufactured by: Solid State Equipment Ltd, Lower Hutt, New Zealand

Email SSEL for further information