Datex-Ohmeda CAPNOMAC ULTIMA, Руководство по обслуживанию

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CAPNOMAC ULTIMA
TM
SERVICE MANUAL
5-1
5 DETAILED DESCRIPTION OF MODULES
5.1 Gas sampling system
The function of the gas sampling system is to draw sample gas into
the monitor at a fixed rate and to separate impurities and
condensed water from the stream.
The sample gas enters the monitor through the water trap, where it
is divided into two flows (see Figures 5.1). The main flow goes
into the measuring system (described in Section 5.2) and the side
flow goes to damping chamber. The task of the side flow is to
cause slight atmospheric depression inside the trap container and
thus pull down moisture in gas into the container. Both flows are
separated from the sample in flow by hydrophobic filter. Incoming
water does not pass the filter but falls into water container.
Because the sampling line is narrow, thick fluids like blood or
mucus will not propagate at all. When the line is clogged, it cannot
be cleaned but replaced.
Special tube(s) is used to balance the sample gas humidity with that
of ambient air (see Figures 5.2 and Tables 5.1). The tube will
prevent errors caused by the effect of water vapor on gas partial
pressure when humid gases are measured after calibration with dry
gases.
CAUTION:
The material of this special tube is mechanically
fragile. Small leakages may occur if the tube is bent or kinked.
Ahead of the ACX measuring unit there is a magnetic valve, which
is used to set the zero point for each gas. Room air is drawn into
the system through this zero valve.
After the ACX measuring unit the main flow is divided into two
in models with i-parameter. One flow goes into oxygen measuring
unit and the other into ASX agent identification unit.
The pressure valve opens and measures the pressure gradient
between the O
2
measurement flow and the O
2
reference flow. This
pressure gradient reflects the condition of the D-FEND™ water
trap filter. The measurement is performed 30 seconds after every
auto-zeroing, occlusion, and gas calibration. It is also performed
whenever software detects the difference value to be less than
-5 mmHg (the pressure
is greater than 5 mmHg). If the
difference value is less -5 mmHg, the message ‘REPLACE
TRAP’ results.
January 15th, 1997/6