5327.400 Vapor 2000 05/99 Function Description Page 12
For internal use only. Copyright reserved.
GBF5327400T01.fm 28.08.01
3.5 Dependency of positive/negative pressure on ambient pressure
and backpressure
The operating range of the Vapor 2000 is limited between –100 and 200 hPa referred to the
ambient air pressure at the vaporizer outlet.
The pressure in the Vapor 2000 is somewhat higher than the ambient pressure, because the
fresh-gas flow at the flow control elements builds up backpressures of up to 150 mbar.
The Vapor 2000 cannot differentiate between a permanent backpressure and an ambient
pressure affected by altitude. Consequently, the influence on the delivered concentration
corresponds to the data quoted (see “Dependency on air pressure” on page 11).
With effective O2 flushing on Dräger anaesthetic machines, a negative pressure of up to
100 mbar is created at the vaporizer outlet. 100 mbar of negative pressure has the same
effect as a 1000 metre rise in altitude or a lowering of the boiling point by around 3.5 °C
(cf. “Dependency on temperature” on page 6).
To protect against excessive pressure (e.g. when the fresh gas hose is kinked), the
Vapor 2000 has a self-resetting pressure relief mechanism. At high pressures, fresh gas
is vented to atmosphere.
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