TVC ColcheK 2 User manual

The Validation Centre (TVC) Limited
Unit 15, Brinell Way, Great Yarmouth, Norfolk, NR31 0LU, UK.
01493 443800 01493 443900 [email protected] www.tvcalx.co.uk
ColcheK 2TM
Instruction Manual
V1.1

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Contents
1.0 Introduction
1.1 Unsuitable applications
2.0 Complete unit, layout and connections
3.0 Lighting column inspection
3.1 Setting up: probe
3.2 Inspecting wall loss: first scan
3.3 Continuing the inspection
3.4 Finalising the Inspection
3.5 Setting the threshold
3.6 Setting the time off period
3.7 Depth reading
3.8 Likely indications
4.0 FAQ / Troubleshooting
5.0 Additional information
6.0 Annex 1: Unit set up and internal set up view

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1.0 Introduction
The ColcheK 2™ is a specialised, non-destructive inspection tool for the detection and
estimation of corrosion damage near and belowground level in planted, steel lighting columns
and similar structures.
At and just below ground level around lighting columns there is an environment rich in
moisture, chlorides and oxygen, an environment which promotes the corrosion of steel
structures. The high stress zone for lighting columns is also at ground level, consequently, any
loss of metal in this region can significantly reduce the strength of the column and may lead
to collapse. Unfortunately, the corrosion can be just below ground level, on the external
surface of the column and impossible to see without expensive excavation.
Allowing you to check this critical zone without having to excavate or in any other way prepare
the column., the ColcheK 2™ is a unique application of the through transmission, eddy-current
inspection technique. No preliminary preparation of the lighting column is required, the low
frequency electromagnetic system is non-contacting and does not emit or use any hazardous
radiation.
By design, no special skills are required to use the ColcheK 2™ or interpret the results.
The ColcheK 2™ works by comparing the wall thickness of the column at and below ground
level with the thickness above ground (around 150mm above ground), At this above ground
point there is rarely any major damage, and any significant corrosion can be easily seen.
1.1 Unsuitable applications
NOT suitable for the inspection of the swage joint on lighting columns
NOT suitable for the inspection of flange mounted columns
NOT suitable for the inspection of aluminium or stainless-steel columns

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2.0 Complete unit, layout and connections
1 Display unit
2 ColcheK 2™ unit
3 Ultrasonic receiver (optional)
4 Probe (shown with optional ultrasonic depth transmitter fitted)
5 Battery charger
6 On / off switch
7 Wake-up button
NB: The operator also needs a key to open the access doors on the columns.
6
7
4
5
2
3
1

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3.0 Lighting column inspection
3.1 Setting up: probe zero
1 Determine and observe the electrical safety requirements of the lighting authority.
2 Open the access door on the column.
3 Visually confirm the state of the column at a level about 150mm (6 inches) above
ground level.
4 Place the coil system of the ColcheK 2™ around the base of the column.
5 Switch the unit on using the main switch and wake the unit up using the “on” control
on the display module. The following screens will be seen.
6. Push the probe down the inside of the column, against the wall, until the tip of the
probe is just below level with the top coil. See Fig. 1 below. It does not matter where
the probe is placed round the circumference of the column.

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Fig. 1
7. Press the Down button on the display. The system will count down to zero.

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8. Once zero has been reached the system will display 100% on all bar graphs.
Continue down the column until the probe tip is approx. level with the lower part of the drive
coil. The display will read at or near 0.
Up / down
buttons

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3.2 Inspecting Wall Loss: First scan
If, as you push the probe down the inside of the column, the tip of the probe passes a region
where there is wall loss, the bar graph readings will rise above zero, indicating the presence
of significant wall loss.
3.3 Continuing the Inspection
The probe ‘sees’ about one third of the circumference. It will not detect a defect on the far side
of the column unless the defect is very large.
To ensure that nothing is missed, insert the probe in four positions, roughly equally spaced
round the inside of the column. There is no need to reset the calibration at each insertion,
once set, it is good for the whole column.
If a re-zero is required, press the Down arrow, re-position the probe to the top part of the drive
coil and press the Down arrow again.
3.4 Finalising the Inspection
If there is a defect, the four scans will have shown its presence.
If a defect has been found, it is advisable to extend the inspection.
By moving the probe up and down, locate the mid-point of the corrosion area and mark the
probe level with the bottom of the door opening. Pull the probe back up until the display reads
zero (level with the bottom part of the drive coil and mark the probe. The distance between
the two marks is the depth of the defect. Push the probe back down to the defect point and
read the appropriate scale on the display. This will be the loss of wall thickness.
Make one or two scans at intermediate positions round the circumference to find the worst
area and gain information on the vertical and circumferential extent of the defect.

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3.5 Setting the Threshold
The ColcheK 2™ has a facility to set an acceptance threshold. Once set, any wall loss area
equal to or above the threshold will be indicated on the display, and the display background
will turn red.
The bar graph reading on bottom the display will show the threshold setting and give a
graphical display of any indications and how close they are to the threshold point. To set the
threshold level follow the below instructions:
1. Switch the unit on and ‘wake up’as normal.
2. Zero the probe as previously described. If no column is available a temporary zero can
be obtained by pushing the Down arrow button. A full zero as described in Section 3.1
will need to be carried out prior to inspection.
3. Press and hold the ‘A’button to bring up the ‘set up’screen. Use the ‘up’arrow button
to set the required threshold level.
4. Press the ‘A’button to exit the threshold ‘set up’screen.
5. The desired threshold is set; inspect as normal.
3.6 Setting the Time Off Period
The time off period can be set by following the below instructions.
1. Switch the unit on and ‘wake up’as normal.
2. Zero the probe as previously described. If no column is available a temporary zero can
be obtained by pushing the down arrow button. A full zero as described in Section 3.1
will need to be carried out prior to inspection.
3. Press and hold the ‘A’button to bring up the ‘set up’screen. Use the Down arrow
button to set the required off time.
4. Press the ‘A’button to exit the Set Up screen.
5. The desired off time is set. Inspect as normal.

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3.7 Depth reading (optional)
The ColcheK 2™ display has an indication of the depth the probe is at within the column
relative to ground level.
This system uses an ultrasonic transducer and must have a reasonable line of sight between
the transmitter mounted on the probe and the receiver fitted inside the column door. To use
the depth measurement, follow the below instructions.
1. Fit the ultrasonic transmitter to the probe close to the lower end making sure the
transmitter faces upwards and using the splitter cable provided, connect the probe and
transmitter to the “probe” connector on the ColcheK 2™. Connect the ultrasonic
receiver to the connector on the ColcheK 2™ handle and fit the receiver inside the
column with the receiver facing downwards. See Fig 2. below
Fig. 2
2. Position the ColcheK 2™ probe at the zero position (see Fig 1) and zero the ColcheK
2™ as normal.
3. Locate the defect as found before and keeping the probe steady use the ‘B’button to
select the depth meter screen. Read the depth directly off the screen. Press the ‘B’
button again and read the relevant bar graph to confirm the extent of wall loss.

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3.8 Likely Indications
1. Corrosion zones on lighting columns are large, typically 50mm or more vertically and
extending one quarter of the way round the circumference. In looking for significant
defects you are not looking for single pinholes.
2. Most columns that have been many years in service will show some corrosion at
ground level.
3. What determines significant wall loss depends on the following factors.
a) The age of the column relative to the wall loss (rate of corrosion)
b) The position of the column and its exposure to high winds.
c) Potential for additional loads to be put on the column such as festive lights, advertising
banners, hanging flower baskets, etc. All the above should be taken in to account when
deciding if a column is fit for purpose or not rather than deciding purely on a ColcheK
2™ reading alone.
NB: Follow the requirements and specifications of the lighting authority.
4. All columns have a cable access hole. With the usually specified planting depth, the
cable access hole is approx. 300mm below ground and will show on the ColcheK 2™
as a point of 100% wall loss. Beware of columns that are not planted deeply.
4.0 Frequently Asked Questionns
Do the electrical cables and switch gear have any effect on the equipment performance?
No. Trials have proved they have no influence on the equipment readings.
Does it matter if the power is on?
Not as far as the ColcheK 2™ is concerned, however health and safety precautions should
be observed.
Does it matter if the column is full of water?
No. The ColcheK 2™ probe is sealed against the ingress of water.
Is the system affected by rubbish in the column?
No, however tin cans and general rubbish should be carefully removed to allow full access
for the ColcheK 2™ probe.
If the column is beside a wall and the drive coil cannot be fully closed, will this affect the
readings?
No. Position the drive coil as far round the column as possible. Readings will be unaffected
even on the far side of the column.
What do I do if the column has been planted to deep and the access door interferes with the
drive coil position?
Do not attempt to set up the ColcheK 2™ on this column. Use the set up from a previous
column. While this may not be ideal, significant areas of corrosion will still be indicated.
Will the system work on non-round columns?
Yes. Hexagonal and similar shaped columns can still be inspected using the ColcheK 2™.

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Are readings effected by galvanising, paint and bitumen coatings?
No. Paint and bitumen are not electrically conducting so are ignored by the ColcheK 2™.
5.0 Additional Information
5.1 Switching off
The machine switches off automatically after the selected time (see Section 3.6). If you have
not completed the inspection, just press the ‘wake up’button again, briefly, and the unit will
re-start with the old settings (there is no need to re-calibrate). If you want to switch the unit off
use the main switch on the unit.
5.2 Run time
If the battery started fully charged andthe unit were kept switched on continuously, the battery
would last approx. 6 hours. Due to the auto switch off and the time taken to walk from column
to column and off time between readings, the working life between charges is approx. 8 hours,
enough to cover a normal working shift.
5.3 Battery status and cut off
Being battery powered, the ColcheK 2™ has a battery status meter on the display to give the
operator an instant indication of battery condition. With a fully charged battery the indicator
will be Green and over to the right-hand side, gradually falling to the left as the battery voltage
decreases.
The ColcheK 2™ also has a battery cut off circuit which will not allow the unit to switch on
when the battery voltage reaches 10.5V.Tests prove that the readings are unaffected until the
battery drops below 10 volts so the cut off is set as a safety feature to prevent inaccurate
readings being taken.
5.4 Battery Charging
Use the standard 12V charger supplied. The ColcheK 2™ uses a sealed lead-acid battery so
there is no danger of over charge or of memory problems with the battery.
5.5 Resolution and accuracy
In a column with reasonable access, a local change of 2% in wall thickness can be detected.
The absolute accuracy depends on the extent and nature of the defect but is typically about
5% of wall thickness. Large defects of uniform wall loss give more accurate readings.
5.6 Safety considerations
It is the operator’s responsibility to ensure that all safety requirements regarding access to the
lighting column are met.
The equipment is totally enclosed.
The maximum differential voltage within the equipment is 30V DC. Power is supplied by a
12V sealed lead-acid battery and protected by a 5A fuse.
The probe has a nylon external case and the internal wiring is further insulated inside the
probe to provide double insulation. Provided there is no serious and obvious damage to this
double insulation, there is no possibility of contact between the electronics of the equipment
and any external electrical system.
The drive coils are transformer isolated from the rest of the electronics. While the current
flowing in the drive coils is several amps, the drive voltage is only a few millivolts and there is
no arcing hazard.

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When inspecting the column, the operator must be careful not to dislodge the electrical system
in the column.
5.6 Disposal
To meet our obligatons under the WEEE directive we have financed a collection point for the
recycling of this product once it has reached the end of its normal working life. In these
circumstances, please contact us for further instructions.
For further information on equipment calibration or disposal, please contact TVC.

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6.0 Annex 1: Unit Set Up and Internal View Set Up
Full unit set up
Internal view