SLE SLE2000 HFO, Руководство по обслуживанию, Страница: 16 / 84

SLE2000 HFO Service Manual
Doc No. SM/0001: Issue 7.0
Page 16 of 84
3.2.1 C
ONVENTIONAL
V
ENTILATION
Air and oxygen supplies are connected directly to the blender.The output of the blender is supplied via
panel mounted regulator REG.1 (inspiratory pressure) and solenoid valve SV1 to the inspiratory nozzle in
the exhalation block. It is also connected to the normally closed port of SV3 (the wave shape solenoid)
and the large volume chamber.
In inspiration mode the valve SV1 opens and allows a flow of blended gas into the patient circuit via the
inspiratory nozzle. This flow opposes the constant fresh gas flow and creates an inspiratory pressure.
The function of the large volume chamber and valve SV3 is to delay this flow of gas during the inspiratory
phase when the waveform taper switch is "on". On expiration SV3 de-energises and dumps to atmosphere
so that the expiratory airway pressure falls rapidly as in square mode.
REG2 (CPAP) is also supplied from the oxygen blender. This front panel mounted regulator controls the
flow of blended gas from the CPAP nozzle in the exhalation block. This gas being a constant flow in
opposition to the fresh gas flow creates a CPAP/PEEP pressure in the patient circuit.
NOTE: Any changes of CPAP pressure will also change the peak inspiratory pressure; this is arranged so
that the tidal volume is always constant and unaffected by changes in CPAP.
REG3 is an internal regulator which regulates the blended gas to a working pressure of 10 psi. NV2 sets a
7LPM bleed to atmosphere. This is to ensure that the oxygen blender has a constant flow through it at all
times to maintain its accuracy.
This bleed is fed to the oxygen monitoring cell, whose output is connected to the digital FIO
2
display
circuitry in the electronics module.
NV1 is adjusted to set a 5 LPM blended gas flow into the fresh gas port on the front panel. This flow
passes through valve SV2 (fresh gas dump solenoid) which will dump the fresh gas should the patient
circuit pressure reach the high pressure alarm threshold. RV2 is a pre-set relieving valve which prevents
pressures greater than approx. 120cmH
2
O developing in the patient circuit.
Both the SLE2000 single use patient circuit (N2188) and the reuseable patient circuit (N2220) incorporate
a restrictor close to the inspiratory port of the ET connector. This generates a nominal 20cmH
2
O pressure
in the fresh gas supply system as long as there are no leaks. Pressure transducer PTR2, located on the
A0702/02 PCB, monitors the fresh gas pressure and associated circuitry will activate a leak alarm should
this pressure fall below 17.5cmH
2
O and activate a block alarm if the pressure rises above 80cmH
2
O.
3.2.2 HFO O
PERATION
HFO pressure is determined by a 0-4Bar panel mounted pressure regulator REG4, resulting in HFO peak
airway pressures in the range 0 to ±45cmH
2
O. The HFO driving gas stream is rotated in the exhalation