DETECTOR OF COATING DEFECT

All ADCA products

are designed and produced in France

DDRC 3 (Direct Current Voltage Gradient technique - DCVG)

DDRC_DCVG
DDRC_DCVG

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DDRC_DCVG man
DDRC_DCVG man

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DDRC_DCVG sea

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DDRC_DCVG

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The new DDRC 3 is the latest generation of coating defect detector using the DCVG technique

The DDRC makes it possible since 1995 to search for pipelining defects using the DCVG technique with an accurancy of 10 cm.

Its detection principle is based on the separation of the gradients emitted by a rectifier from interference gradients (stray currents, telluric currents). This is done by the means of two electrodes sticks.

 

A cyclical interrupter at a frequency of one hertz is placed in series within the pipe supply connection. Pulses flow at the level of the gradients within the ground and are read by the DDRC 3.

ADVANTAGES OF DDRC 3

 

Thanks to its electronic processing, the DDRC 3 is 10 times more sensitive than other DCVG equipments.

 

  • Detect defects earlier and operate through resistive soil (dry or porous asphalt) with an accuracy of 10cm

  • Perfectly filtered (no influence of stray currents and alternative currents 50/60 Hz)

  • Self-adjusting system (patented)=no need to adjust the off-set manually

  • Possibility of using dry sticks (without electrodes)

Basic principle

All emitted current returns to the source. As part of cathodic protection, the current emitted by the rectifier passes through the cables, the anodes, the ground, the faults, any eventual control points, the structure, and the structure, eventually returning to the source (the rectifier).

At the level of the anode the currents are distributed within the ground.

At the level of the lining defect, currents are concentrated and return to the rectifier by means of the pipe.

 

A potential between two points can therefore be observed on the ground, and we can thus establish the direction to take in order to go towards the defect.

Detection principe

The DDRC 3 synchronizes to the interrupteur (SRDDRC) switch and will only analyze the gradients at the cutoff of the rectifier to display the difference between the value of rectifier “on” and rectifier “off”. Through a patented process, the display is not subjected to any interference caused by the potential between the two sticks. Therefore, the device does not entail any tedious settings and allows for accurate, precise and effective measurements.

 

An operator holds the sticks with the arms stretched out and with the line of the shoulders parallel to the pipe.

The device then defines a direction to the right or to the left, indicating the direction of the gradients (these gradients are proportional to the current flowing within the pipe). The operator moves with a "crab" motion along the pipe under examination in such a way as to observe an increase in the amplitude of the gradients. Once the operator has walked beyond a defect, the directions of the gradients reverse. The operator then walks back in order to balance the gradients where his/her sticks indicate. The perpendicular from the midpoint of the straight line formed by the sticks at this location indicates where the pipelining fault lies.

Step1
Step1

The operator holds the sticks with the arms stretched out and with the line of the shoulders parallel to the pipe.

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Step2
Step2

The device indicates the direction of cathodic protection gradients.

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Step8

Once a defect is located, it is necessary to accurately measure the potential of the gradient where the defect is.

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Step1

The operator holds the sticks with the arms stretched out and with the line of the shoulders parallel to the pipe.

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Technical specifications

DDRC (detector):

 

  • Autonomy: 10 hours

  • Input sensitivity: 20 micro volts

  • Input impedance: 20 mega-ohm

  • Measurement: scales to 3, 10, 30, 100, 300, 1000, 3000 mV

  • Dimensions: 325 X 210 X 90 mm

  • Weight: 1.7 kg

SRDDRC (interrupter):

  • Autonomy: 48 hours

  • Contact resistance when closed: <10 milli-ohms

  • Switching capacity: 100 volts at 30 Amps (or more if need)

  • Dimensions: 185 X 105 X 85 mm

  • Weight: 1.2 kg

DDRC 3 full set

Additional item(s)

Dry sticks

Ultra light and robust aluminum sticks equipped with a copper rod.

Electrode sticks

Transparent polycarbonate sticks equipped with a copper rod in a solution of Cu/CuSO4 (copper sulfate supplied).

Ideal for use on hard ground (eg asphalt).

References and documentation

References

Description

 

DDRC 3 full set

 

Additional items

SRDDRC with GPS antenna

GPS antenna for SRDDRC

2 electrodes sticks

2 dry sticks

 

Metrology

Certificate of calibration DDRC

Certificate of calibration SRDDRC

Code   

 

E100245

 

 

E100241

E100011

E100174

E100175

CERT005

CERT040