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D-Tec Vaporizer
August 2001
O & M Manual Part No. 1107-0622-000
9.7
Effects Of Output At Varied Altitudes
The D-Tec Vaporizer has been calibrated in % v/v and the calibration is not affected by ambient
pressure changes. The partial pressure of the delivered agent at any selected dial setting varies directly
with the changes in ambient air pressure. The required dial setting may be calculated using the
following formula:
Required Dial Setting
=
Normal Dial Setting % v/v x
The table below shows the dial setting on a D-Tec Vaporizer at altitudes of 1000 m and 2000 m
respectively above sea level:
Normal Dial
Required Dial Setting %
Setting % v/v
At an altitude of
At an altitude of
1000 m (3282 feet)
2000 m (6564 feet)
5
5.5
6
10
11
12.5
14
17
18
9.8
Effects Of Ambient Temperature
The performance of the D-Tec Vaporizer is not significantly affected by the temperature variations
within the operating range specified in Section 9.3.
9.9
Effects Of Back Pressure
Fluctuating Back Pressure does not significantly affect the output of the D-Tec.
Steady Back Pressure does not significantly affect the concentration of the agent delivered (v/v), but
does increase partial pressure of the agent. The increase is in the ratio of total back pressure to the
vaporizer calibration pressure of 760 mm Hg.
9.10
Effects Of Carrier Gas Composition
Small output decreases can occur when the carrier gas composition is changed from 100% oxygen.
When either air or nitrous oxide is employed as the carrier gas, the output is lowered compared to the
output when oxygen is the carrier gas. This effect is the greatest (up to 20% of setting) at low flows
when nitrous oxide is employed, but using nitrous oxide reduces the required inspired concentrations
of volatile agent which can, depending upon the proportion, mitigate the decreases in output from the
vaporizer.
760 mm Hg
ambient pressure (mm Hg)
