Mindray WATO EX-55Pro, Service Manual

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2.2.5 Breathing System
2.2.5.1 Overview
The breathing system provides a closed loop for the anesthetic gas. The CO2 in the patient’s
expired gas can be inspired in the inspiration phase to maintain the temperature and humidity
conditions of the patient’s exhaled gas. During inspiration, the drive gas depresses the bag inside
the bellows or the doctor presses manual bag to force the inside gas to enter the patient’s lung.
During expiration, the patient’s expired gas goes into the bag inside the bellows or manual bag.
Sodalime canister 34 absorbs CO2 the patient expires. The following diagram shows the
pneumatic circuit of breathing system.
Manual and mechanical ventilation modes are selected through the manual/auto switch 41. When
manual ventilation is selected, the doctor presses manual bag 42 to supply gas for the breathing
system. APL valve 43 is used to adjust the pressure inside the pneumatic circuit in case of manual
ventilation. When mechanical ventilation is selected, the ventilator starts to work. It controls the
drive gas to depress the folding bag inside bellows 45 and supply gas for the breathing system as
per the selected ventilation mode.
Breathing system is connected to the anesthesia machine main unit through the circuit adapter. Its
tubes are all built in except the tube connected to the patient and the O2 cell cable, as shown
below.
Drive gas
Fresh gas
AGSS
Patient