Teledyne 3060e - Ultra Trace oxygen analyzer - Manual (Page 13)

Teledyne Electronic Technologies
Analytical Instruments
2-3
Operational Operational Operational Operational Operational Theor Theor Theor Theor Theory y y y y Ultra Ultra Ultra Ultra Ultra T T T T Trace Oxyg race Oxyg race Oxyg race Oxyg race Oxygen Anal en Anal en Anal en Anal en Analyz yz yz yz yzer er er er er
Ultra Trace Sensor
The analyzer incorporates an electrochemical ultra trace O
2
sensor exclusively
designed by TET/AI (U.S. Patent #5,085,760). The sensor shows exception-
ally high sensitivity for O
2
and remarkable long-term stability. The highly
accurate sensing element of the sensor enables it to detect as low as 0.5 PPB
of O
2
in a gas mixture.
Ultra Trace Sensor Components
The components of the sensor are shown in Figure 2-2. The main body of the
sensor is made of clear acrylic. The sensor has a U-shaped profile with an open
top end. The left-hand wall of the sensor has a circular aperture for mounting
the O
2
-sensing cathode. A high surface area cadmium anode is inserted through
the top stainless steel plate. A fine porous frit disc is mounted at the bottom of
the sensor in order to remove any dissolved O
2
by continuously sparging the
electrolyte with O
2
free gas. A baffle plate is inserted between the sparger and
the sensing electrode to minimize the noise level caused by the sparger.
The main body of the sensor contains 15% aqueous KOH electrolyte. A
thermistor is inserted into the sensor’s main body through an opening on the top
stainless steel mounting plate. The opening serves as a port for adding water/
electrolyte to the sensor. An electrolyte level detector is also mounted through
the top stainless steel plate.
PURGE GAS OUT
WATER LEVEL
DETECTOR
PURGE GAS IN
TOP STAINLESS
STEEL PLATE
CELL BODY
CATHODE
(+)
SIDE STAINLESS
STEEL PLATE
SAMPLE OUT
SAMPLE IN
CATHODE
O-RING
THERMISTOR
(-)
ELECTROLYTE
ZERO GAS BUBBLES
(OXYGEN-FREE)
CADMIUM ANODE
BAFFLE PLATE
Figure 2-2. Ultra Trace Sensor Components