Divesoft He/O2 Analyzer, Руководство пользователя

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He/O
2
Analyzer
Special accessories
8.2 Pressure measuring
A pressure sensor can be connected to the analyzer. The pressure sensor is generally attached
to the connector with the regulator described in the preceding chapter (instead of the plug),
so that it is possible to cut off the gas output and measure only the pressure. Of course, it is
possible to simultaneously measure the pressure and the gas composition.
The attachment equipped with a pressure sensor (and other elements) is shown in the
illustration in the following chapter.
After plugged in pressure sensor in basic format display shows measured pressure in the
range 0―400 bars, například
Oxygen: 20.1 %
Helium: 30.5 %
Temperature: 25.5 °C
Pressure: 202.6 bar
As in the basic mode, Temperature data shows the temperature of the gas inside the analyzer.
With the
MODE
key it is possible to format the display in which are shown the absolute
and relative pressure, e.g.:
Pressure: 202.6 bar
Relative: 52.6 bar
In this format, the
CAL
key can be used to nullify the relative pressure and thus measure, for
example, the increase of pressure in the tank. In the stated example, the pressure was nullified
when reaching absolute pressure of 150.0 bars and from that time a pressure increase of 52.6 bars
occurred. This option is useful when blending mixes using the partial pressures method.
Connection of the pressure sensor is involved in some of the analyzer’s other functions.
In gas-mixing calculation, the display shows the immediate pressure, which makes it possible
to directly fill the tank according to the displayed procedure. In the continual analysis mode,
the measured pressure is used as an additional quantity for sounding of the alarm. When
measuring the gas composition in the calculation and simulation of gas mixing, the gas pressure
is automatically taken over. The pressure sensor can be connected to the analyzer
8.3 Measuring of pressure and tank temperature
When filling a pressure tank with gas, the temperature of the gas (and thus the tank) increases
by up to ten degrees Celsius. According to Gay-Lussac’s law, less gas will thus go into a warm
tank than into a cold one at the same pressure.
A direct consequence of this phenomenon is the fact known from experience that the
pressure in a freshly filled tank gradually decreases. Depending on the ambient temperature,
this decrease persists for up to several hours, which complicates the preparation of a gas mix