Northern Meditec Crius V6, Operator'S Manual

Page: 155 / 182

155 / 182
Check valve (CV3) prevents patient’s expired gas from polluting the components in the
upstream of this valve under the single fault condition of expiratory limb being occluded.
Safety valve (SAV) ensures that the pressure in the inspiratory limb is kept within the safe
range and provides flow to the spontaneous inspiratory channel when the system is powered
down. It is controlled by electromagnet. When the ventilator is in normal working state, the
electromagnet is powered on and the safety valve is in closed state. When the pressure in the
inspiratory limb exceeds the system setting pressure, the electromagnet is powered down and
the safety valve is opened to release excess pressure. When the system is powered down, the
electromagnet is in power-down state and the safety valve is opened by default. The patient
inhales the external gas through the spontaneous inspiratory channel.
The expiration valve assembly integrates the expiration valve (EXV) and flow sensor (Q2).
Q2 is a diaphragm differential pressure flow sensor. It monitors the front and rear pressure
and Flow Calibration processes for calibration via the differential pressure sensor P4. PE is
an expiratory pressure sensor which monitors the airway pressure. F6, F5 and F12 are filters
which protect the upstream components from being polluted by the patient’s expired gas.
R1and R2 are resistors which flush weak flow introduced to the expiration valve from the gas
source, preventing water vapour condensation from occluding the pressure measurement
tubes. CV2 is a check valve which prevents gas from flowing in the reverse direction.
F7 and F8 are bacteria filters. They are connected to the inspiration port and patient port
when they are used by the ventilator. The nebulizer is pneumatic. The drive gas is introduced
into the nebulizer via the nebulizer connector on the front panel; and the liquid medicine is
nebulized, enters the inspiratory tube, and reaches the patient’s lungs. The pneumatic
nebulizer can be connected only when the machine is connected with high-pressure O2.