Component Description And Function; 2-Way Proportional Valve; 4-Way Valve; Accumulator Tank - DeVilbiss iGo Series Servicehandbuch

C O M P O N E N T D E S C R I P T I O N A N D F U N C T I O N
COMPONENT DESCRIPTION AND
FUNCTION

2-Way Proportional Valve

A 2-way proportional valve ensures that the selected flow rate is
delivered to the patient in either Continuous Flow or PulseDose
mode. When the unit is in PulseDose mode, the pressure switch
triggers the proportional valve to deliver the correct bolus of oxygen
for the selected flow rate.

4-Way Valve

The 4-way valve directs the pressure and vacuum created in the
compressor to the two sieve beds in alternating cycles. The cycle
shift is controlled by the PC board and occurs when a pre-
determined pressure is reached in the accumulator tank.

Accumulator Tank

The accumulator tank holds the concentrated oxygen and releases
it to the patient at a specified liter flow.

Battery Pack

The battery pack contains two rechargeable lithium ion batteries of
22 nominal volts, 9 amp-hours of total capacity and allows the iGo
to operate free of connection to an external power source. After
300 charge/discharge cycles, the battery's capacity may drop to
about 80% of the original capacity. A variety of factors, such as age
of battery, flow rate, and PulseDose or Continuous Flow Mode
operation, determine the duration of operating time; operating time
will degrade with Battery use and age. The following table provides
estimates of amount of time that a new, fully charged iGo Battery
will operate.
Typical New Battery Operation Time
Flow Rate Continuous Flow
1.0 4.0 hours
2.0 2.4 hours
3.0 1.6 hours
4.0 —
5.0 —
6.0 —
NOTE–Be sure to check the battery charge level before travel;
battery will discharge over time.

Cover

The external plastic cover parts are molded of impact resistant and
flame retardant plastic resin and held in place by six T-20 screws.

Compressor

A dual-head compressor creates pressure and vacuum
simultaneously and is driven from a single brushless DC motor
whose speed is regulated by the motor control board.

Final Bacteria Filter

The final bacteria filter prevents contaminants from reaching the
patient through the oxygen supply.

Intake Silencer/Filter

The intake silencer/filter filters the air drawn into the compressor
removing particulate matter and reduces the sound of the intake.
The silencer/filter should be inspected every 3 years and replaced if
needed.
PulseDose (20 BPM)
5.4 hours
4.7 hours
4.0 hours
3.5 hours
3.2 hours
3.0 hours

Molecular Sieve Beds

Molecular sieve beds contain a synthetic alumino-silicate that
attracts and holds nitrogen in a magnetic bond. Two molecular
sieve beds work in tandem: one bed removes nitrogen from the air
passing through it while the other bed releases the removed
nitrogen back into the room air.
Moisture or hydrocarbons contaminate molecular sieve material
causing it to lose its nitrogen adsorbing properties, which in turn
decreases the oxygen concentration. To allow the iGo to exhaust
these possible contaminants, anytime the unit is started, it should
run for a minimum of 20 minutes before it is turned OFF.

Motor Control Board

The motor control board controls the motor speed of the DC
brushless compressor. The control board also monitors the
compressor's temperature and speed and communicates that
information to the PC board.

Motor Mount System

There are two types of motor mounts used in the iGo: Black rubber
mounts connect the compressor to the bracket; spring mounts
connect the bracket to the base of the cover.

Pressure Regulator

The pressure regulator stabilizes the flow of oxygen to the patient
and establishes back pressure on the system. It is preset at 5 psi
(34.5 kPa) and should not need adjustment in the field.

Printed Circuit Board (PC Board)

The printed circuit (PC) board monitors and controls the operation
of the iGo, including cycling pressure and vacuum between the two
sieve beds and initiating visible and audible alerts if abnormal
operation is detected. The OSD is located on, and controlled by,
the PC board.

Pressure Switch

When the iGo is operating in PulseDose mode, a pressure switch
detects inhalation as a reduction in cannula pressure and opens a
2-way proportional valve that delivers the prescribed bolus of
oxygen as the patient begins inhalation. If the pressure switch does
not detect a breath at least every 30 seconds, it triggers a No
Breath Detected alert. If it does not detect a breath after another
minute, it automatically switches the unit into continuous flow
mode.

Purge Valve

Before the 4-way valve cycles pressure and vacuum to alternate
sieve beds, the PC board activates the purge valve for 0.8
seconds. During this time, the purge valve sends oxygen from the
pressurizing bed to the evacuating bed breaking any remaining
nitrogen bonds and cleaning the bed in preparation for its upcoming
pressure cycle.

Sieve Bed Check Valves

Check valves, located between the outlet of each sieve bed and
the accumulator tank, allow oxygen to pass from the sieve beds to
the accumulator tank, but prevent the reverse flow of oxygen from
the accumulator to the sieve beds.
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LT-2044