GF Signet 4150 Turbidimeter - Manual (Page 19)

19 Signet 4150 Turbidimeter
Vapor Purge System
If the air inside the 4150 is too humid it will cloud the optical glass cuvette surface and will interfere with the transmission of light.
A continuous vapor purge system in the 4150 keeps the inside of the instrument dry.
• The air inside the unit is dried by a replaceable desiccant pouch (order number 3-4150.380) located
under the measuring cell.
• System heat is used to warm the air.
• A fan inside the instrument continuously circulates heated dry air around the measuring cell and the
À ow-through cuvette.
• A humidity detector in the 4150 continuously monitors the desiccant condition. When the internal
environment approaches the point where condensation may occur, the instrument will display
DESC as a warning.
• The DESC warning does not interrupt the operation of the 4150, but the cause of the high condensation must be checked.
• If DESC ALARM is turned on (see OPTIONS: EXTENDED on pg. 18), any active relay will go into alarm condition (if set up in
the OPTIONS menu) and the 4 to 20 mA output will be locked to the ERLV (Error Level) value you set in the 4 to 20 mA output
con¿ guration in the OPTIONS menu (pg. 10): OFF, 0 mA, 2 mA or 4 mA. Factory default is OFF.
DESSICANT COMPARTMENT
OPEN ONLY FOR MAINTENANCE
Desiccant Pouch
3-4150.380
Cleaning the Flow-Through Cuvette
All glass cuvettes must be clean and free of marks or scratches.
• Clean the interior and exterior with a detergent solution and then rinse several times with distilled or deionized water.
CAUTION: Do not use a bottle brush to clean the cuvette. Scratches will alter the optical quality of the glass.
To replace a cuvette:
• Shut off the À ow using the shutoff clamp.
• Unscrew the old cuvette and replace with a fresh clean one.
• Do not touch the glass surface of the cuvette. Fingerprints can compromise the accuracy of the measurement.
Replacing Desiccant
• To install or remove the desiccant pouch, open the round port on the side
of the 4150.
• Open the desiccant bag and place it inside the instrument.
• Close the access door quickly to minimize exposing the desiccant to the
atmosphere.
• In high humidity locations place two desiccant pouches in the instrument.
Operating Tip
• To speed up recovery after a DESC alarm, disconnect the sensor
interconnect cable (connector on the right side of the Turbidimeter power
supply) for 2 seconds and then reconnect it.
• Order spare desiccant pouches to keep on the shelf.
Signet Turbidimeter
ENTER
Measuring Cell
Sensor Interconnect cable
Cuvette
CAUTION
Move the cuvette away from the
measuring cell opening to prevent
accidental spills into the instrument.
NOTE: In regions where moisture or high humidity is prevalent, more than
one desiccant pouch may be needed, and desiccant may need to be
monitored more often.