User Guide

6
PROCESS CONNECTIONS - Pressure
To avoid confusion on instruments fitted with more than one measuring system, the connections are marked with the same
colour as the corresponding recording pen colour.
The recorder is fitted with NPT threaded connection(s) and all pipelines attached to it must be secure and leak proof. PTFE
sealing tape must be used to make a pressure tight join to the recorder connections.
Use pressure tubing of sufficient size and rating to make a connection from the measuring point in the flow pipe or
vessel to the fitting(s) on the recorder.
Slope the run of the pipe-work in such a way that any condensate is drained away from the recorder, and fit an
appropriate shut-off valve. For measurement of steam pressure and other hot vapours, form a condensate trap below the
recorder.
It is recommended that a needle valve be installed in the pressure line close to the instrument to enable pressure to be
admitted gradually. It can also dampen any pressure pulsation and/or fluctuation.
PROCESS CONNECTIONS - Temperature
Capillary tubing: The tubing between the bulb and recorder should be routed so that it is not subjected to large
temperature changes and should be supported in cleats. Bends must not be less than 25mm (1inch) radius and under no
circumstances must the tubing be cut.
Where the tubing is likely to be exposed to an extreme atmosphere, the exterior should be treated with corrosion resistant
paint.
Location of Bulb (Detecting Element):
Immersion type bulb
The instrument bulb should be located where it is subject to the true temperature of the measured medium. Temperature
gradient within the medium must be allowed for, and with bulbs allowing variable depth of immersion (compression gland
type), the bulb position should be varied experimentally until the optimum position is found.
The full length of the sensitive portion must at all time be immersed in the medium, but direct contact with the source of
heat to the medium must be avoided.
When securing the bulb in its location, it should be prevented from twisting.
Where a pocket is supplied, this should be securely installed before the bulb is inserted. It may be that the thermal
response of a pocketed bulb is improved by filling the intervening space with a medium such as oil.
General Maintenance
• keep the instrument clean and treat with care
• where there is a risk of corrosion the bulb should be inspected periodically
• if corrosion is evident, it should be removed by non-abrasive treatment
• any contamination on the bulb should be removed
Clearscan™ Recorder Series - Operating and Service Manual