NELLCOR PURITAN BENNETT LP6 Plus, Техническое руководство

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Pneumatic System Overview Pneumatic System Overview Pneumatic System Overview Pneumatic System Overview
LP6 Plus, LP10, and LP20 Technical Manual
November 2000
Page 4-2 Page 4-2 Page 4-2 Page 4-2
Pneumatic System Overview Pneumatic System Overview Pneumatic System Overview Pneumatic System Overview
Refer to Functional Block Diagram at the end of this section. Num-
bers in parentheses refer to component identification numbers on
the diagram.
Air is entrained into the ventilator through a 0.3 micron inlet filter
(1). Negative pressure for entrainment is accomplished by the with-
draw stroke of the piston in the mechanical piston pump assembly
(5). Passing through an inlet check valve (4), the air enters the cylin-
der and becomes pressurized by the forward piston stroke. Air exits
through a pump outlet check valve (10) and through a 62 micron,
stainless steel gross particulate filter (11). Before exiting to the
patient through the
PATIENT AIR
PATIENT AIR PATIENT AIR
PATIENT AIR
outlet tube, the air passes through one
additional 40 mesh gross particle screen (13). A mechanical pres-
sure limit system (LP10 and LP20) uses an adjustable spring to
close an opening between the patient air path and atmosphere. As
the pressure in the patient air path increases beyond the force of the
spring, air escapes and the pressure is regulated.
Intermittent Mandatory Ventilation (IMV) is accomplished by use of
a parallel path incorporated into the manifold. This path bypasses
the pump and allows air to move directly to the
PATIENT AIR PATIENT AIR PATIENT AIR PATIENT AIR
outlet tube
after passing through the inlet filter (1) and an inlet check valve (3).
On the forward pumping stroke, a small segment of air delivered to
the patient outlet tube is routed through a three-way electrical
exhalation solenoid valve (14). This portion of air exits through the
exhalation valve port and is delivered to the patient manifold to
expand the exhalation mushroom valve and allow ventilation of the
patient’s lungs.
During the exhalation phase of the ventilatory cycle, the exhalation
solenoid valve de-energizes, relieving pressure on the exhalation
mushroom valve, permitting patient air to exhaust to atmosphere.
The air in the exhalation mushroom is routed back through the
valve and dumped to atmosphere inside the ventilator.
A patient pressure sensing tube passes from the proximal pressure
line to a pressure transducer (51). This transducer is a solid state,
sealed chamber, strain gauge device. The pressure transducer func-
tions from -10 cmH
2
O to + 100 cmH
2
O, allowing both negative and
positive exhalation pressures, using the appropriate patient air lines
and accessories.