Teledyne TED-60 - Medical application oxygen monitor - Manual (Page 14)

2 Operations 2 Operations 2 Operations 2 Operations 2 Operations
Teledyne Analytical Instruments 2-6
centimeter water pressure pulse will produce a .11 atmosphere, or an 11% increase in
the total and therefore partial pressure of oxygen. Assuming that the sensor is fast
enough to track this pressure pulse, an unpressurized reading of 50% oxygen will
increase to 55.5% if
the sensor is subjected to a pressure cycle of 100 cm H
2
O. The
reading will rise proportionally less for smaller pressures.
Humidity Humidity Humidity Humidity Humidity
Humidity does not directly affect the accuracy of the sensor’s measurement.
However, when a nebulizer or other device is used to increase moisture levels in gas
mixtures, the moisture actually dilutes the mixture. This dilution effect decreases the
oxygen concentration.
For example, if an 80% oxygen gas mixture is humidified to saturation at room
temperature, the resulting gas mixture will contain only 77.5% oxygen. Your TED 60T
oxygen analyzer accurately measures decreases in the oxygen concentration due to the
dilution effects of moisture added to gas mixtures.
Caution: Caution: Caution: Caution: Caution: As with all oxygen sensors, excessive condensation on the sensing surface As with all oxygen sensors, excessive condensation on the sensing surface As with all oxygen sensors, excessive condensation on the sensing surface As with all oxygen sensors, excessive condensation on the sensing surface As with all oxygen sensors, excessive condensation on the sensing surface
of the T-7 will block the diffusion of oxygen to the sensor, rendering it
of the T-7 will block the diffusion of oxygen to the sensor, rendering it of the T-7 will block the diffusion of oxygen to the sensor, rendering it of the T-7 will block the diffusion of oxygen to the sensor, rendering it of the T-7 will block the diffusion of oxygen to the sensor, rendering it
inoperative.
inoperative. inoperative. inoperative. inoperative.
Should this occur, gently wipe the sensing surface of the T–7 with a cotton swab
and allow to air dry. To prevent this, TED recommends installing the sensor on the dry
side of the breathing circuit at all times.
Water condensate on the exposed cable contacts at the rear of the sensor may
affect the oxygen reading and should be removed by shaking out the condensed water
and allowing the sensor to air dry.
Temperature Temperature Temperature Temperature Temperature
A thermistor circuit in the T-7 oxygen sensor adjusts for ambient temperature
changes in the range of 0–40°C (32–104°F). Since the thermistor that compensates for
these changes is located in the rear of the sensor assembly, it is important that gas mix-
tures, flowing over the front of the sensor, be at room temperature. Reading errors may
occur if hot gases from a heated humidifier are directed past a sensor teed into a breath-
ing circuit.
A small thermal tracking error may be encountered in application areas where
the entire sensor assembly is placed in the gas mixture to be analyzed (e.g., incubators).
No adjustments should be made during this period (about 1 to 2 hours), since this error
will be eliminated when both the thermistor and sensing electrode have had sufficient
time to come to thermal equilibrium.