Vivax Metrotech vLocDM, Руководство пользователя

Страница: 12 / 54

Page 6 of 47
3 Introduction
Introduction
3.1 About this Handbook
This handbook is designed to provide the user with a comprehensive understanding of the operation of the
vLocDM system. The handbook assumes some understanding of Cathodic Protection techniques, it covers the
operation of the equipment, the techniques to gather data, storing and retrieving the data in a format that can be
analyzed by a competent engineer and a brief explanation of how to use the data to form an understanding of
the condition of the pipe network.
3.2 Overview of vLocDM System
The vLocDM (Defect Mapper) has been designed to:
• identify the position of coating defects
• identify shorts to other structures
• help categorize the faults
• help plan and prioritize remedial work
The vLocDM uses the latest locating and signal processing techniques to plot the current gradient of an industry
standard low frequency (3Hz) profiling current. The current is typically applied at CP stations so the disruption of
the pipeline can be minimized.
The Loc-150Tx, 150W transmitter (vLocDM transmitter) is used to apply a signal current to the anode bed. The
pipeline returns the signal via coating faults back to the transmitter. The transmitter is designed to be powered
from CP (Cathodic Protection) stations, AC or external batteries, eliminating the need for batteries.
The non-intrusive measuring device, the vLocDM receiver, takes measurements along the pipeline and plots
the results directly onto the screen of the receiver. There is no need to carry extra logging and display devices.
All the data is displayed and logged into the receiver and can be downloaded to a spread sheet or dedicated
analysis program such as Spectrum XLI
TM
or similar.
A +/- 3m accuracy GPS antenna is included with the system. It links to the vLocDM receiver via Bluetooth radio
link. The GPS enables the user to generate real time current gradient graphs and guides the user back to a point
of interest by highlighting the user’s position on the graph. This feature is called the “walk back” feature. The
system can also be integrated with high accuracy GPS systems and software packages, for example Trimble
and TriGlobal Inc.
Storing the results also has the benefit of facilitating the technique of comparative tests. Comparing the
results from previous surveys of the same length of pipe allows the CP engineer to establish trends of coating
deterioration.
The A-frame fault finding accessory is used to accurately locate the position of a fault. An arrow points the user
to the position of the fault whilst quickly and efficiently graphing the characteristic shape and magnitude of fault
signal on the receiver's display. This ensures the user minimizes the chances of misidentification.