Installation; Verification Of Battery Free Power Loss Alarm; Sequence Of Operation; Oxygen Sensor Technology - Ceramic Zirconia Sensor - Invacare Perfecto2 IRC5PO2AW Service Manual

3 Installation

3.1 Verification of Battery Free Power Loss Alarm

Check the concentrator for proper operating conditions.
1. If the unit has been in below-freezing temperatures, allow it to warm up to room temperature before operating.
2. The concentrator may need to be turned on for four to five seconds to charge the Battery Free Power Loss Alarm. Connect power cord
to outlet and turn the concentrator on. Turn flow control knob counterclockwise and flow will begin IMMEDIATELY. Set flow rate
to five L/min. Let the unit run for 30 minutes, then turn unit off.
3. Unplug the power cord and press On/Off (I/O) switch to the On (I ) position. An intermittent audible alarm will sound. This confirms
proper operation of the Battery Free Power Loss Alarm. Turn On/Off switch Off (O).
4. Connect power cord to outlet and turn on concentrator. Unit will beep on start-up.
5. Check the oxygen concentration per specifications after 30-40 minutes running time.

3.2 Sequence of Operation

Turning On (I ) the power switch applies 230 VAC to the compressor motor, hour meter, transformer, cooling fan and the printed circuit
(P. C.) board.
Room air enters the compressor via the cabinet filter and the compressor inlet filter. The air is compressed by the Wob-L pistons in the
compressor to a pressure of 144.79 kPa (21 p.s.i.).
As increased pressure creates increased temperature, a heat exchanger is used to lower the temperature before the air enters the 4-way
valve. It is then channeled to a sieve bed containing the adsorption material. Restriction downstream of the sieve bed causes pressure to
build up inside the sieve bed which is necessary for the adsorption process. A small amount of relatively pure oxygen enters the top of the
second bed through a restrictive leak in the pressure equalization (P. E.) valve with the balance entering a storage tank. The nitrogen removed
is exhausted back from the bed through the 4-way valve into room air. A muffler is located at the exhaust end of the valve to muffle the
sound of the exhaust as it exits the concentrator.
The oxygen not being used to exhaust is channeled into the storage tank. The pressurized oxygen is regulated down to 5 p.s.i. (34.4 kPa), enters
an accurate flow-measuring device, flows through the outlet HEPA filter and check valve, then out to the patient.
The electrical activation of the 4-way Valve is accomplished every 8 to 15 seconds by the pressure sensor and P. C. Board electronics when the
pressure reaches a set point of 144.79 kPa (21 p.s.i.) output flows 4 L/min and above or 16 p.s.i. (110.32 kPa) output flows 3 L/min and below. The
time between cycles is dependent on altitude, flow rate and internal environmental factors.
A P. E. valve opens just prior to the shift of the 4-way valve. This allows highly concentrated oxygen to enter the just exhausted bed from the top.
This additional pressure allows the bed to start its cycle at a higher pressure. The P. E. valve will close just after the shift of the 4-way valve.
If main power is lost, the Battery Free Power Loss Alarm will sound a short "BEEP", with a long pause after. All units are equipped with a diagnostic
alarm system that signals if the pneumatic pressure or electrical systems malfunction. The troubleshooting guide in this manual explains the
alarm system signals and reasons, in detail. Refer to Troubleshooting.
3.3 SensO

Oxygen Sensor Technology - Ceramic Zirconia Sensor

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3.3.1 Technical Description

The oxygen being produced by the concentrator flows out of the product tank and into the flowmeter. A small flow of oxygen produced by the
unit is sent through a precision orifice to the oxygen sensor mounted on the printed circuit board.
As the oxygen enters the sensor, it passes through a screen and contacts the sensing disk.
Electric current flowing through a metal film resistor heats the disk in excess of 300° C.
Oxygen molecules contact the electrode of the disk and pick-up extra electrons to become oxygen ions. These oxygen ions are attracted to
the electrode on the bottom of the zirconia sensing disk. Because of the crystal structure of the zirconia, only oxygen ions can pass through.
When the oxygen ions reach the bottom electrode, the extra electrons are released from the oxygen ions and oxygen molecules return to the
air. The number of electrons is directly related to the oxygen concentration. The electrons travel to the P.C. board where they are counted
and the oxygen concentration reading is calculated.
A microprocessor on the P.C. board contains software that interprets the signal being received from the sensor. It compares the signal to
clinically acceptable limits. Signals outside of the clinically acceptable limits generate responses in the form of lights, audible indicators, and/or
system shut-down.

3.3.2 Operating Sequence

Once the power switch has been turned On (I), the SensO
acceptable oxygen and the oxygen sensor to stabilize. The GREEN light will illuminate (indicating normal system operation) while the oxygen
sensor is warming up.
After five minutes, if the oxygen purity exceeds 85% ± 2%, the GREEN light will continue to illuminate.
1154245-F-02
circuit will wait five minutes for the concentrator to begin producing clinically
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Installation
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