A-3
A.1.3 Theory
This product is an electronically driven and electronically controlled ventilator. Oxygen is
provided by high- or low-pressure oxygen port. Air is inhaled from the ambient atmosphere
due to vacuum produced by the turbine motor. During the inspiratory phase, the inspiration
valve opens. Gas with specific O
2
concentration is formed in the upstream of inspiration
valve after Air and O
2
are mixed. Such gas becomes gas with specific flow or pressure after
passing through the inspiration valve and enters the patient’s lungs via inspiratory tube.
During the expiratory phase, the inspiration valve is closed while the expiration valve opens.
The gas reaches the expiration valve from the lungs via the expiratory tube and is finally
discharged out of the human body.
When the turbine works to inhale Air from the ambient atmosphere, Filter (F1) filters dust in
the Air. Filter (F2) is an HEPA filter for filtering bacteria. After the machine is used or placed
for a period of time, dust or foreign substance absorbed on the surfaces of the two filters at
the Air inlet can occlude the Air inlet when the dust or foreign substance is accumulated to a
certain extent. This may cause insufficient Air intake of the machine and compromise the
ventilation performance of the machine. Vacuum sensor (Pfilter) at the Air inlet monitors the
vacuum at the Air inlet in real-time, effectively judges filter occlusion at the Air inlet, and
gives the replacement prompt.
Check valve (CV1) ensures unidirectional flow of low-pressure O
2
. Filter (F3) filters foreign
substance in the high-pressure O
2
supply. Regulator (REG) regulates and stabilizes the
pressure of high-pressure O
2
supply to ensure the stability and repetitiveness of flow
outputted by the rear proportional solenoid valve (PSOL).
Filter screen (F4) is placed before the flow sensor to stabilize gas flow for the convenience of
sensor measurement. Flow sensor (Q1) is a hot-wire mass flow sensor which does not require
calibration.
The gas supply part includes three parallel limbs: high-pressure O
2
, low-pressure O
2
, and
low-pressure Air. The high-pressure O
2
and low-pressure O
2
converge before mixing with Air.
High-pressure O
2
and low-pressure O
2
cannot be used at the same time. Flow sensor (Q1) is
placed at the common outlet of low-pressure O
2
and high-pressure O
2
to monitor O
2
. Room
air enters the machine after passing through filter (F1) and HEPA filter (F2).
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