Datex-Ohmeda Engstrom Carestation, Technical Reference Manual

Page: 29 / 225

2 Theory of Operation
1505-1018-000 08/07 2-3
2.1.1 Primary Gas Inlet
Compressed gas enters the EC through an inlet fitting {2} that is particular to
the institution’s supply system. The gas is filtered through a 2-micron
particulate filter {3} and then a 0.5-micron coalescing particulate filter {3a} as
it enters the ventilator’s “pneumatic engine” manifold. The Air Pipeline Inlet
filter assembly {3a} is standard on all configurations. The O2 Pipeline Inlet
Filter assembly does not come standard, but is an orderable option. The
0.5-micron filter protects the EC from pipeline particle and liquid aerosol
contamination.
A high-pressure transducer {4} having a dynamic range of 0 to 8.3 bar
(0 to 120 psi) is tapped at the outlet of the filter. This transducer monitors the
adequacy of the supply pressure. Failures of supply gas, coupling hoses or an
occluded filter are identified by the supply pressure transducer.
Next in the downstream path of flow is a check valve {5}. The check valve
prevents backflow from the EC that would possibly contaminate the supply
pressure lines. For example; if the O
2
supply were to be lost, the check valve in
the O
2
channel will prevent Air from moving back into the O
2
supply lines.
Air
25 psi
172 kPa
25 psi
172 kPa
Flow
Sensor
Flow
Sensor
O
2
H T
H
T
P
R
High Pressure
Transducer
Primary
Inlet
Check
Valve
Regulator
Flow
Valve
Regulator
Flow
Valve
Check
Valve
High Pressure
Transducer
Primary
Inlet
Test
Port
Test
Port
P
P
Inlet
Filter Optional
Inlet
Filter Standard
{2}
{2}
{3}
{3}
{4}
{3a}
{3a}
{5}
Air
25 psi
172 kPa
25 psi
172 kPa
Flow
Sensor
Flow
Sensor
O
2
H T
H T
P
R
High Pressure
Transducer
Primary
Inlet
Check
Valve
Regulator
Flow
Valve
Regulator
Flow
Valve
Check
Valve
High Pressure
Transducer
Primary
Inlet
Test
Port
Test
Port
P
P
Inlet
Filter Optional
Inlet
Filter Standard
{5}
{5}
{4}