Elcometer 331 SH Operating Instructions Manual page 60

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EARCH HEADS
All search heads are fully interchangeable. Changing from one type of search head to another is
quick and easy; simply switch off the Covermeter, swap search heads, switch on again and zero
the Covermeter.
Narrow Pitch Standard Deep Cover Borehole Probe
Figure 32. Search head search fields
Use the Narrow Pitch search head when the reinforcement bars are close together, i.e. when the
pitch of the reinforcement bars is narrow.
Use the Deep Cover head to measure depth of cover over reinforcement bars deep within the
structure. Because the Deep Cover search head only resolves bars if they are adequately spaced
(centre-to-centre pitch more than about 1½ times their cover), for covers shallower than 70 mm, the
Standard search head should be used in preference.
Note: Orthogonal sizing is not possible when the Covermeter is set to detect stainless steel and the
SIZE function is therefore removed from the reading screen when this bar grade is selected.
Borehole Probe
The Borehole Probe is used to locate reinforcement bars, tendon ducts and other metallic objects
in the vicinity of holes drilled into concrete. The probe will also measure depth of cover over a limited
range, making it ideal when attempting to drill through a structure without making contact with
reinforcement bars or tendon ducts. The Borehole Probe is available in two lengths; 400 mm (16")
and 1000 mm (40").
The Borehole Probe has two search fields; forwards looking and sideways looking. Readings can
be taken looking forward from the end of the probe or looking sideways (at right angles to the axis
al
of the probe) - Figure 33. A switch on the handle controls which search field is active.
al. Whenever the position of the switch is changed, the Covermeter must be zeroed.
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