Thermometer Installation - Ametek LAND RT8A User Manual

Thermometer
The Land RT8A 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 RT8A thermometer target spot size table.

2.4 Thermometer Installation

The location of the RT8A 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 RT8A 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 RT8A thermometer, the
following criteria should be considered:
• If the installation area is not clean or free from dust, smoke or water
spray, then a 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 a 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.
Page 4
User Guide
RT8A