Chapter 3
Theory of Operation
REF 580-1000-02 G
Esprit® Ventilator Service Manual © Respironics, Inc.
3-3
Delivery System
The delivery system includes the components that condition and control the
flow delivered to the patient based upon operator-selected parameters. The
blower draws room air through the blower inlet filter (F1) and the muffler
(silencer) and outputs flow to the air valve assembly (AV). A pressure switch
(PS1) monitors oxygen input pressure. The oxygen water trap/inlet filter
assembly filters wall oxygen, and the oxygen regulator (REG1) regulates oxygen
down to 23 pounds per square inch, psi (1.5 kilopascals, kPa). Regulated
oxygen then enters the oxygen valve assembly (OV) and the crossover solenoid
(SOL1). The air and oxygen valves (AV and OV) are controlled by the
microprocessor, based on continuous feedback from the air and oxygen flow
sensors (FS1, T1 and FS2, T2).
Delivery System Components
Blower Inlet Filter
(F1)
The blower inlet filter removes coarse particulate from ambient air as it
is entrained into the blower assembly. See section 4 for periodic
maintenance information.
Cooling Fan Filter
The cooling fan filter removes coarse particulate from ambient air
entrained by the cooling fan. See section 4 for periodic maintenance
information
Muffler (Silencer)
The muffler reduces the noise of air flow into the blower by channeling
the air through a baffled system lined with sound absorbing material.
Blower
The blower draws room air though the air inlet filter and outputs the air
that is delivered to the patient and provides the pilot pressure that can
actuate the safety valve. The blower contains a DC motor and a series of
stator and impeller assemblies. It can provide at least 200 LPM of flow.
Blower speed is automatically adjusted to account for differences in gas
density due to altitude. The altitude can be adjusted from the hardware
screen in diagnostics mode. The High Pressure alarm limit setting also
affects blower speed.
