K-Patents PR-03 - Manual (Page 53)

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6 Regular maintenance 47
6 Regular maintenance
The need for regular maintenance is minimal, due to the construction with no moving parts, no trimpots and
with a solid-state light source. The following rules apply:
• Keep the sensor head and the Indicating transmitter clean and dry.
• Check that the ambient temperature is not above +45 ◦ C (113 ◦ F). The sensor head should not be too hot
to keep a hand on.
• If your refractometer has prism wash, check that it works (in Normal display, press the soft key A,
Prism wash
).
6.1 Checking the sensor moisture
The PR-03 sensor has an internal moisture detector. The moisture reading can be checked on the Indicating
transmitter display (Display / Sensor Head). Check the moisture reading once in a quarter.
An increasing signal indicates either condensate forming in the sensor head (if the process temperature is
below ambient) or prism leakage. If the moisture reading exceeds 30 %, replace the dryer (see below). If
the reading exceeds 50 %, check the prism seals.
The dryer (desiccant) is a plastic package inside the sensor head cover. When the dryer is effective, it is
yellow. When it turns green, it needs to be replaced. The dryer cannot be reactivated by any means, it
must
be replaced. You can order new dryer packages (drying agents/desiccants), spare part number PR-
9107, from K-Patents or your local distributor.
For instructions on how to open the sensor head to replace the dryer, see Section 6.3 for the standard length
sensors (Sanitary refractometer PR-03-A, Compact process refractometer PR-03-D, Process refractometer
PR-03-M and Valve body refractometer PR-03-W) and Section 6.4 for the Probe sensor PR-03-P.
6.2 Checking and replacing prism or prism gaskets
Once a year check that the prism surface is smooth and clean. If the prism is scratched or the gaskets seem
to leak, order spare parts from K-Patents or your local distributor and follow the procedure described below
to replace them.