Instruction manual

NGA 2000 MLT Hardware
CHECK AND REPLACEMENT OF ELECTROCHEMICAL OXYGEN SENSOR
18 - 7
Emerson Process Management GmbH & Co. OHG
Instruction Manual
90002929
07/2006
18.4 TEO
2
-Sensor
The TEO
2
cell is a fuel cell which measures oxygen concentration by oxidizing a lead oxide.
The electrical charge per oxidation cycle yields a current directly proportional to the oxygen
concentration. This is current is measured, calibrated and displayed. The over all reduction
capacity of the cell gives a limited lifetime of the cell.
Under normal operation conditions (low levels of O
2
) the lifetime exceeds 6 months. At elevated
concentrations however the lifetime decreases. At end of life the cell has to be replaced by a spare
part.
❍ Switch analyzer to its “purging/zero gas mode” via analyzers operating front panel keys
(see Software Manual).
❍ Remove the cover and the screws on top of the cell.
❍ Remove existing sensor and dispose of in accordance with national, federal, state, and local
regulations.
❍ Inspect inside of cellblock for signs of residual liquid or deposits on the contact pins.
If liquid is present, use appropriate protective equipment. Deposits on the contact pins can
be removed by wiping with a damp cloth or using the eraser from a pencil. Do not use
abrasives (i.e. sandpaper) as this will damage the contact pins.
❍ Control the O-rings. If they have any damages replace them.
❍ Unpack the replacement sensor and remove the short circuit plug from the new cell.
❍ Push the new cell in the o-ring holder of the housing lid
(the contact side to the lid, the gas diaphragm side to the bottom of the cell housing).
TEO
2
-SENSOR
The electrochemical O
2
-sensor contains electrolyte which is caustic and
can cause serious burns to skin. Do not ingest contents of sensor !
CAUSTIC !