6300A Operator’s Manual
NewTechMedicalLimited -4-
2.2 Basic Operation Principle
The high-pressure oxygen enters the pressure reduction valve I, and the output pressure from the
pressure reduction valve I is stabilized at 0.25MPa (already adjusted before ex-factory). The output
gas from the pressure reduction valve I enters the electromagnetic valve. In inspiring, the
electromagnetic valve is open; the two-way outputs enter the flow valve and the pressure reduction
valve II respectively. The one entering the pressure reduction valve II presses on the diaphragm in
the expiration valve by means of the gas pressure to control the opening and closing of the
expiration valve, and the output pressure is stabilized at 0.05MPa (already adjusted before ex-
factory). The other one enters the flow valve. The tidal volume value could be changed through
adjusting the flow valve. The pure oxygen entering the gas line is mixed in accordance with a
certain proportion in the gas room. The air enters from the venturi-type valve, and a unidirectional
valve is installed in the venturi-type valve to prevent the gas overflowing. The sponge gas entrance
is adopted for the unidirectional valve to reduce noise and filtrate the gas to be breathed in. A
safety valve is installed on the side face of the gas room to prevent that the air pressure is too high
and will make hurt to a patient. When the air pressure exceeds the set value of the safety valve
(5.1kPa~6kPa), the safety valve can open automatically and the gas will be discharged from the
safety valve. The electromagnetic valve will be closed in expiration, the pressure exerted on the
diaphragm of the expiration valve will disappear, and the diaphragm will loose. Thus the gas room
connects with the atmosphere directly. The gas compressed in the bellows by the ventilator will
discharge to the atmosphere through the expiration valve. The process above will be repeated
along with the breath rhythm.
During the above procedures, it is the electromagnetic valve that controls the gas flowing direction,
and is controlled by the mainframe board. In inspiration the electromagnetic valve will be opened
while in expiration it will be closed. In the Fig. 2, the display plate is used for the digital display for
the respiration rate, breath frequency, the tidal volume and the oxygen concentration, the display of
the corresponding display lamps and the display of the luminous line of the pressure. The
mainframe board is the central processing unit of the ventilator circuit part. It not only controls the
opening and closing of the electromagnetic valve, but also receives and processes the pressure
signal, the flow signal. It receives the inputs from the panel and sends the signal that will be
outputted to display to the display plate. The voltage stabilizing power supply provides the circuit
needed voltages (+5V, +12V, −12V). The functions of the subsystems above are set and adjusted
by the keys on the panel.
The front and back panels drawings of the ventilator are shown in Figure 2-2, Figure 2-3.