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KOREC Direct - Construction And Surveying Supplies > Faq
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| FAQ - What Items are and How to use them... | |
Cable Location
Covermeter
Theodolite
Dumpy Level (Automatic Level)
Spirit Level
Clinometer
Gas Detection
Metal Detection |
Cable Location
Locators can detect:
* Alternating (AC) electrocmagnetic signals radiated due to currents
flowing in conductive buried services.
Locators do not detect:
* Cables without a current
* Well balanced high voltage cables
* Fibre Optic Cable
* Plastic or Clay non metallic pipes
EziCAT Locating Methods
Passive Signals are already present on many pipes and cables, there are 2 catagories:
POWER: detects all services carrying a power signal including live
(loaded/energised) electrical power cables.
RADIO: Low frequency radio transmitter ground return currents.
Used to trace metallic services, which may not have a power signal present, eg: telecom.
The method of searching a location prior to excavation is called the sweep search. Mark
out the site to be excavated. With the
detector set to POWER mode cross the whole site from “left to right”, marking
any responses located. Repeat “front to back”.
Then set the detector to RADIO mode and repeat.
Pinpointing a Service and Direction
EziCAT100 & EziCAT200 - Audio tone pinpointing is automatically adjusted during the
sweep process.
Once you have pinpointed the service, if you turn the EziCAT 90°, the signal will drop
off and you will have the direction in which the cable is running.
Service tracing and identification
Connecting the EziROD transmitter directly to a service (such as a valve, called
CONNECTION mode) or placing it over a service (INDUCTION mode) allows an active signal to
travel the service, making detection possible.
INDUCTION mode will automatically activate other nearby serivces, but current is reduced
by increasing depth. Use CONNECTION mode to avoid coupling.
The transmitter should be used 10 paces away from search area.
Summary
* Always begin in POWER mode.
* No Current = No Locate
* Always repeat sweep pattern every 50cm when excavating.
* Detects and traces buried metallic services
* Service your equipment regularly! (Servicing with KOREC - 0845
6031214)
Covermeter
http://en.wikipedia.org/wiki/Rebar
Theodolite
http://en.wikipedia.org/wiki/Theodolite
Dumpy Level
http://en.wikipedia.org/wiki/Builder%27s_level
Spirit Level
http://en.wikipedia.org/wiki/Spirit_level
Clinometer
http://en.wikipedia.org/wiki/Clinometer
Gas Detection
http://en.wikipedia.org/wiki/Levels_of_Gas_Detection
Metal Detector
http://en.wikipedia.org/wiki/Metal_detectors
What do we mean by Motion and Non-Motion?
Motion detectors first started to arrive on the market in the early 1980's. Before this,
all metal detectors were 'non-motion'. If you think of tuning a radio to your favourite
radio station, you may occasionally have to re-tune it because it may have drifted off the
station. This applies to non-motion detectors. As you scan the ground, the tuning may
slightly drift from where originally set, but very easily brought back to the correct
level. Motion metal detectors are self-tuning; once switched ON, they are continuously
re-adjusting themselves for optimum operation. The metal detector search head has to be
kept moving or scanning the ground in order to detect metal, the moment movement is
stopped, metal detection stops, hence the word MOTION. The big advantage with this
principle is that they are extremely simple to use and operate. Secondly, because of their
sophisticated electronics, they are not affected as greatly by mineralised ground as
non-motion metal detectors and therefore the penetration is greater. Also better
discrimination is achieved without significant loss of depth.
What Does The Discrimination Control Do?
The Discrimination control allows iron, silver paper and other rubbish items to be ignored
by the metal detector, while still detecting gold, silver, copper and other non-ferrous
metals. The higher the control is set, the more objects will be ignored. Be careful not to
set it too high though, as you may find yourself rejecting good targets. For example when
the control is set at maximum only the most conductive targets, copper and silver, will be
detected. As gold jewellery is usually alloyed with a lower quality metal it would be
rejected in this case. With experience you will learn the best place to set your
discrimination control. When starting out we recommend you set it reasonably low, as it is
better to dig a few trash items than to risk ignoring potentially valuable targets.
Why Is It Not Possible To Only Find Good Items?
Unfortunately a metal detector is not able to distinguish items as being 'worthless' or
'valuable'. It can however determine the conductivity of an object. Objects of low
conductivity, such as iron, can easily be distinguished from silver or copper object,
which has high conductivity. The problem occurs in the so-called 'grey' area in-between.
For example a 9-carat gold ring and a ring pull can appear very similar to a metal
detector as they have a very similar conductivity.
What is Target ID?
Target ID is the metal detectors way of displaying the identity of a target in the form of
a number. This complements the discrimination control by giving you the information the
metal detector uses when it makes the decision whether or not an object should be
detected. This allows you to determine accurately an objects conductivity, giving a strong
clue as to its identity. On metal detectors with a discrimination control it was only
possible to determine whether an object was more or less conductive than a chosen value.
For example, if the discrimination control was set half way and an object was found, it
would not be possible to tell whether it were a pound coin or a silver shilling. Target ID
will give you this information, as the shilling would be more conductive so a higher
number would be displayed. This information is presented in two ways. Firstly a bar is
shown when an object is detected. If the object is of low quality, iron or steel, only one
or two segments will be shown. For a very good object, for example a silver shilling, the
bar will fill up completely. This provides a very quick way of identifying the object. For
more accurate identification, the Target ID number shows the point on the discrimination
control at which each target would be rejected. As an example, a modern 5 pence piece
would only just be rejected when the discrimination control is set somewhere between 50
and 60. When detected, the bar will fill up half way and the number '55' is shown.
How Deep Will A Viking Metal Detector Detect?
An obvious question, but one that can be difficult to answer. Firstly the larger the metal
object is, then the deeper it will be detected, e.g. an old pre-decimal penny will be
detected deeper than a new decimal penny, simply because it is a larger metal object.
Secondly, the length of time the object has been in the ground the shape of the item and
how it lies in the ground can have an effect. Rings or loop shaped objects lying parallel
to the search head produce excellent results for detection. Thirdly, heavy mineralised
ground can reduce the penetration of your detector. Taking all this into account and
dependent on which VIKING model is used, single coins will be found anywhere between 10cm
(4 inch) to 22.5cm (9 inch) with larger objects up to 1 metre (39 inch).
What Is The Purpose Of The Sensitivity Control?
The sensitivity control increases or decreases the metal detectors depth penetration in
the Motion mode. Obviously, one wants to detect as deep as possible, but there may be
times when the metal detector gives false signals or behaves in an erratic manner. This
could be due to bad ground or some electrical interference from power lines or
transmitters etc. In these circumstances, backing off the sensitivity level should help to
achieve reliable operation.
Is A Viking Metal Detector Difficult To Operate?
Simple answer, NO. Our lower priced Non-Motion Metal Detectors are easily set or tuned to
the correct level for correct operation. Our top of the range motion detectors are even
easier, because of the more sophisticated electronics, automatically tunes the detector
for you. Obviously all our metal detectors come with full operating instructions and
remember our customer services are only a phone call away or email.
What Is Meant By Mineralization Or Ground Effect?
The ground contains quantities of iron oxides of which some soils are more prolific than
others. These oxides have built up over many centuries on land mainly worked and farmed by
humans. Other land can contain magnetic iron oxides, which are naturally present in the
ground. Metal detectors are affected by this ground mineralization, which is referred to
as ground effect. Beaches also have an effect on the detector caused by the electrical
conductivity of salt water.
Can You Use A Viking On The Beach As Well As Inland?
Using your metal detector on dry sand is exactly the same as using it on an inland site.
However, wet sand is different, being known as conductive. Many thousands of non-motion
metal detectors, like our Viking 1, 5 or 6DX2, have been used continuously on beaches with
fantastic success. Some makes of powerful motion metal detectors are rendered useless on
wet sand, because they give false signals or indications of metal, when there is nothing
there. Our VK20 & 30 both feature a beach mode providing reliable performance on the
beach.
What Does The Membrane Keypad Operate?
Featured on the VK40 the membrane keypad provides an alternative method of setting up the
detector to the traditional rotary controls and switches. All the functions are controlled
from the 5 keys provided. A single key press allows the detection mode to be selected, and
the Discrimination, Sensitivity and Ground settings can be adjusted using a simple menu
system.
What Does The Detector Display Show?
The Liquid Crystal Display provides a wealth of useful features. Target ID provides a
visual indication of the target identity, and the display also shows at a glance which
mode the detector is operating in. On the VK20 and VK30 the display shows the control
setting as they are adjusted, and the VK40 features a larger display allowing the detector
set-up menu to be used. The display also provides a continuous battery check.
Suggestions welcome - Email sales@korecdirect.com
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