Gas Flow Through The Anesthesia Machine; Overview - GE Datex-Ohmeda Aisys Carestation Reference Manual

Aisys

2.11 Gas flow through the anesthesia machine

2.11.1 Overview

Gas supplies
Gas flow
Gas mixing
Mixed gas
2-36
Refer to Figure 2-27 and Figure 2-28.
Gas comes into the system through a pipeline (1) or cylinder (6) connection. All
connections have indexed fittings, filters, and check valves (one-way valves). Pressure
transducers monitor the pipeline (2) and cylinder (7) pressures.
The O supply failure alarm is derived from the O
2
transducer inputs.
A primary regulator (8) decreases the cylinder pressures to approximately pipeline
levels. A pressure relief valve (3) 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.
Pipeline or regulated cylinder pressure supplies O
engine (4a or 4b) and as pilot pressure (4) for the SCGO
assembly (E). Connection points are also available for venturi
suction (5a or 5b) drive gas supply. An additional O
pressure for the O Flush valve (19) and the auxiliary O
2
The O Flush valve supplies high flows of O
2
the SCGO/ACGO assembly (E/F). The flush pressure switch (20) monitors activation of
the flush valve.
Under normal conditions, with the system switch (10) in the On position, the Alternate
O Disable valve (13) is energized to block alternate O2 flow. Normal gas flows are
2
enabled through their respective selector valves (11). The system controls gas flow
through the flow control valves (12) and derives the individual flow rates through the
hot-wire anemometers (14).
Under system failure conditions (or if Alt O
O Disable valve (13) allows delivery of O
2
the system switch is in the On position.
The mixed gas (15) flows through the electronic vaporizer (D) to the
SCGO/ACGO assembly (E/F). A pressure relief valve (17) on the electronic vaporizer
limits the maximum outlet pressure.
The SCGO assembly (E) directs the mixed gas to the selected circuit:
22 (ABS-circle) or 23 (to Inspiratory port of ABS). On SCGO assemblies, a relief valve
(21) limits pressure in the breathing system to approximately
150 cmH O.
2
The ACGO assembly (F) directs the mixed gas to the selected circuit:
22 (ABS-circle) or 23 (external ACGO port).
pipeline and the O
2
or Air directly to the ventilator
2
regulator (18) decreases the
2
flowmeter (24).
2
to the fresh gas outlet (22 or 23) through
2
is selected), the normally-open Alternate
2
through the Alternate O
2 2
cylinder pressure
2
Flowmeter when
04/08 M1046983