9100c
2-4 M1207026
2.2 Gas flow through the anesthesia machine
2.2.1 Overview Refer to Figure 2-1.
Gas Supplies Gas comes into the system through a pipeline or cylinder connection.
All connections have indexed fittings, filters, and check valves (one-
way valves). Gauges show the cylinder and pipeline pressures.
A regulator decreases the cylinder pressures to the appropriate
system pressure. A pressure relief valve helps protect the system
from high pressures.
To help prevent problems with the gas supplies:
• Install yoke plugs on all empty cylinder connections.
• When a pipeline supply is adequate, keep the cylinder valve
closed.
O
2
Flow Pipeline or regulated cylinder pressure supplies O2 directly to the
ventilator (O2 Ventilator). A secondary regulator decreases the
pressure for the flush valve.
The flush valve supplies high flows of O2 to the common gas outlet
when you push the flush button. The flush switch uses pressure
changes to monitor the position of the flush valve.
A secondary regulator supplies a constant O2 pressure to the flow
control valve.
An electrical switch monitors the O2 supply pressure. If the pressure
is too low, an alarm appears on the ventilator display.
Air and N
2
O Flow A balance regulator controls the flow of N
2
O to the flow control valve.
Oxygen pressure at a control port adjusts the output of the regulator.
This stops flow during an O2 supply failure and ensures that the
hypoxic gas pressures decrease with the O2 supply pressure.
Changes in O2 pressure do not affect Air.
A gear link system on the N
2
O and O2 flow controls helps keep the O
2
concentration higher than approximately 21% at the common gas
outlet.
Pipeline or regulated cylinder pressure directly supply Air to the
ventilator (Air Ventilators). A secondary regulator supplies the air flow
control valve. Because there is no balance regulator, air flow
continues at the set rate during an O
2 supply failure.
Mixed Gas The mixed gas goes from the flowmeter outlet, through the vaporizer
manifold and vaporizer that is ON, to the common gas outlet, and into
the breathing system. A pressure relief valve limits the maximum
outlet pressure.
M1207027 004 MANUAL−DOC, Technical Reference Manual, Technical Reference Manual for 9100c, English−default
Reproduced from the electronic master in MATRIX
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