Low Temperature Thermometer
RT8B
User Guide
4
The AMETEK Land
RT8B
thermometer operates by sensing radiation from within a well
defined ‘field of view’. The intersection of this field of view with the intended target,
determines the ‘target spot’, the area where the temperature is measured. Fig. 3 shows
the
RT8B
thermometer target spot size table.
2.4 Thermometer Installation
The location of the
RT8B
thermometer should be carefully chosen, such that it is
easily accessible and in a position not unnecessarily exposed to heat, fumes or liquid
spray. The sight path between the thermometer and the target, should be as free as
possible from smoke, liquid spray and from the intrusion of machinery. The axis of
the thermometer should be at right angles to the target surface, however, an angle of
up to 45° from the normal is acceptable. It is also important that the intended target
completely
fills the thermometer field of view at the selected installed distance and
that no part of the sight path is obstructed.
NOTE
In some
RT8B
applications, a sighting tube may be required to eliminate any
unwanted reflections from entering the thermometer and to keep the sight path
clear from obstructions. Sighting tubes can also be used to create a ‘stand-off’,
between the thermometer and the process under observation.
When selecting a suitable sighting tube, it is important to ensure that the internal
bore of the tube is at least 25% greater than the largest target spot size over the
tubes length. All distances must be measured from the thermometer datum, which
is located at the front of the thermometer.
When choosing a suitable location for mounting the
RT8B
thermometer, the following
criteria should be considered:
•
If the installation area is not clean or free from dust, smoke or water spray,
then an AMETEK Land air purge system
must
be utilised to ensure that the
thermometer lens is kept free from such airborne contaminants. Ensure that a
suitably conditioned air supply is available.
•
If the surrounding ambient temperatures of the installation area are outside
the thermometer specification, then an AMETEK Land water cooled protective
jacket
must
be utilised to ensure that the thermometer operates at the specified
ambient temperature. Ensure that a suitably conditioned water supply is available.
