Gas Flow Theory of Operation
1 - 18 046-006272-00 A7™ Service Manual
FIGURE 1-10
1.3.4.3 System Switch Assembly
The system switch assembly is the pneumatic circuit on-off valve of the breathing system. It controls
the on and off of the pneumatic circuit and provides system power-off signal when the pneumatic
circuit is switched on, implementing synchronous on/off control on the pneumatic and electrical
circuits of the system. When the system switch knob is rotated clockwise, the valve stem pushes the
valve core to switch on the pneumatic circuit and triggers the tact switches on the system switch
assembly to switch on the electrical circuit at the same time. When the system switch knob is rotated
counterclockwise, the pneumatic and electrical circuits will be switched off at the same time. There is
an exhaust limb on the system switch, which functions to exhaust the residual gas in the backup limb
at power-off to prevent the residual gas in the backup limb from lifting the float of the total
flowmeter.
The system switch assembly is equipped with two tact switches, providing the same functions and
located at symmetrical positions. This design is only used to ensure that one tact switch can operate
properly when the other tact switch fails. When the two PINs of either tact switch are shorted, the
system power supply will be switched on.
To Next Page
Loading...
Need help?
General
