Respironics ESPRIT, Руководство по обслуживанию, Страница: 19 / 329

Chapter 3
Theory of Operation
REF 580-1000-02 G Esprit® Ventilator Service Manual © Respironics, Inc.
3-5
Oxygen Regulator
(REG 1) The oxygen regulator reduces the oxygen supply pressure to the proper
inlet pressure for the oxygen valve (22-24 psig, or 152-165 kPa @ 180
LPM) and supplies the regulated pressure to the crossover solenoid,
which pilots the safety valve.
Oxygen Valve (OV) The oxygen valve assembly contains a stepper motor that meters flow
from the oxygen regulator to achieve the target flow under CPU control,
based on operator-selected parameters. It can deliver up to 200 LPM of
flow.
Oxygen Flow Sensor
(FS2) The oxygen flow sensor measures the flow from the oxygen valve. The
ventilator uses this measurement to provide closed loop control of the
oxygen valve and to compute the flow and volume delivered to the
patient. A thermistor contained in the flow sensor measures the
temperature of the oxygen and provides temperature compensation
information to the microprocessor for delivered flow.
Crossover Solenoid
(SOL1) The crossover solenoid is a three-way valve that supplies either air or
oxygen pressure to pilot (hold) the safety valve closed during normal
ventilation. In its normal state, SOL1 is normally de-energized to pilot
the safety valve with oxygen. If oxygen pressure is lost, SOL1 is
energized and air (rather than oxygen) controls the safety valve.
Check Valve (CV5) The cross contamination check valve prevents the oxygen supply from
entering the air delivery system pneumatics (blower) in the event of a
crossover solenoid leak.
Inspiratory System The inspiratory system includes a manifold where air and oxygen are
blended and the inspiratory pressure transducer (PT3) is connected
through the inspiratory pressure transducer solenoid (SOL4). The
manifold also houses several components designed to ensure patient
safety, including the safety valve pilot solenoid (SOL2), safety valve
(SV), (CV2), inspiratory non-rebreathing check valve (CV3), pressure
relief valve (PRV), and oxygen sensor (OS).
Safety Valve Pilot
Solenoid (SOL2) The safety valve pilot solenoid directs the output of the crossover
solenoid to the safety valve or vents the pilot pressure line to
atmosphere.
During normal operation, SOL2 is energized and directs pressure from
the crossover solenoid to close the safety valve. During a high priority
alarm condition such as an occlusion or ventilator failure mode (VENT
INOP), SOL2 is deenergized to open the safety valve and allow the
patient to breathe room air.
Delivery System Components