Mechanical System Overview
Mechanical System Overview
Mechanical System Overview
Mechanical System Overview
LP6 Plus, LP10, and LP20 Technical Manual
November 2000
Page 4-3
Page 4-3
Page 4-3
Page 4-3
Pumped air is delivered through a 22 mm tapered outlet tube with
locking ribs. Many of the standard patient hoses that are commer-
cially available can be used. Pressure is indicated on a front panel
PATIENT PRESSURE
PATIENT PRESSURE
PATIENT PRESSURE
PATIENT PRESSURE
gauge (52). The gauge reading is generated by the
microprocessor from signals sensed by the pressure transducer
(51). The gauge also identifies the condition of connected batteries
when the
BATTERY TEST
BATTERY TEST
BATTERY TEST
BATTERY TEST
button is pressed. Pressing the
BATTERY TEST
BATTERY TEST
BATTERY TEST
BATTERY TEST
and
the
ALARM SILENCE
ALARM SILENCE
ALARM SILENCE
ALARM SILENCE
buttons simultaneously registers elapsed time from
0-20,000 hours for the scale 0-100.
A mechanical relief valve (2) prevents excessive pressure (greater
than 100 cmH
2
O) by providing a release to atmosphere. This valve is
a mechanically actuated, spring return, one-way leaf valve (2).
Mechanical System Overview
Mechanical System Overview
Mechanical System Overview
Mechanical System Overview
Refer to the Functional Block Diagram at the end of this section.
Numbers in parentheses refer to the component numbers on the
diagram.
The major mechanical elements of the ventilator are the motor/gear-
box (8 and 9), the piston pump (5), the pressure relief valve (2), and
the exhalation solenoid valve (14).
The basic mechanical drive is a brushless DC motor driving a 100 to
1 gearbox. The gearbox drives the crank arm, which in turn drives a
piston within a seven-inch diameter cylinder. An "end-of-stroke"
sensor (7) determines when the machine is to commence counting
the return stroke for positioning of the next volume stroke.
The pump piston retracts a selected number of Hall Effect sensor
codes (24 per motor revolution) until it reaches the correct piston
position for the next stroke. At the end of the air delivery stroke, the
piston reverses direction, passing over bottom dead center with each
breath. This creates a pendulum action which allows shorter
inspiratory times with low volumes. The microprocessor stops the
motor drive once the piston retracts to its correct starting position.
If the patient pressure reaches the high alarm/limit, the crank arm
reverses the piston without passing over bottom dead center.
An over pressure relief valve (2) ensures a dump to atmosphere
when excess pressure is created. This valve is mechanically actu-
ated and preset to release at a pressure between 90 and 100
cmH
2
O, using a spring return.