Mindray A7 Service Manual

A7™ Service Manual 046-006272-00 1 - 91
Theory of Operation Ventilator Pneumatic- O2 Drive Gas
1.9 Ventilator Pneumatic- O2 Drive Gas
1.9.1 Ventilator Pneumatic Drive
Oxygen is the driving gas for the ventilator. In addition to the flow meter block, a high pressure
regulator reduces the supply pressure to 200 kPa (29 psi). This pressure represents the drive gas for
the ventilator.
The drive pressure regulator is placed ahead of the proportional valve that generates the driving gas
flow during the inspiratory phase. This flow fills the bellows dome that surrounds the bellows.
1.9.2 Drive Pressure-High Pressure Regulator (200 kPa, 29 psi)
The drive pressure regulator stabilizes the supply pressure provided to the proportional valve. The
flow generated by the proportional valve is therefore independent of pressure variations at the
supply.
Setting the drive pressure regulator at 200 kPa (29 psi) allows for a maximum inspiratory flow of 110
L/min at the ventilator.
1.9.3 Drive Gas Assembly
The manifold assembly module mainly consists of the inspiratory circuit and PEEP circuit. The
inspiratory circuit goes through the normally closed proportional solenoid valve, which generates a
gas flow of 0 to 110 L/min by the valve drive board. The gas flow of the PEEP circuit goes through the
normally closed proportional solenoid valve, which also generates a gas pressure of 3 to 30 cmH2O
by the valve drive board.
1.9.4 Tube Color Coding
All the internal pneumatic tubes used in the anesthesia system are color coded per the United States
standard.
GAS US STANDARD
O2 GREEN
N2O BLUE
AIR ORANGE

Mindray A7 Specifications

General

Brand	Mindray
Model	A7
Category	Medical Equipment
Language	English