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T
Chapter 4.
This section describes the theory of operation for the EverFlo Oxygen Concentrator.
4.1
PNEUMATIC OPERATION
Refer to Figure 4-1 while reading the following discussion.
The room air is drawn into the unit through the air inlet filter by the compressor. The compressed air is routed to
the sieve beds through an electronically controlled Solenoid Valve Assembly. The Solenoid Valve alternates the
airflow to a pair of sieve beds that allows Oxygen production. The Solenoid Valve Assembly also alternates the
flow through the sieve beds to allow purging of the Nitrogen molecules from the sieve beds.
At startup, the valve/solenoid is de-energized allowing compressed air to flow through both sieve beds until the
pressure sensor builds up to switching pressure. At switching pressure, a 12-volt signal is received at the
valve/solenoid closing off the input and allowing the compressed air to cycle through one of the sieve beds. As
the air is cycled through one of the sieve beds, the molecular sieve material traps the Nitrogen molecules from
the air and allows the Oxygen enriched air to flow through the sieve bed.
At 5 liters of flow, approximately 1/3 of the Oxygen enriched air enters the product tank and the other 2/3 of the
Oxygen enriched air is passed through an orifice in the sieve bed to purge the trapped Nitrogen molecules from
the sieve bed, allowing the sieve material to be ready for Oxygen production during the next cycle.
The concentrated Oxygen is stored in the product tank. The product tank is continuously filled with concentrated
Oxygen and the output from the product tank is regulated at 5.5 psig nominal. The product tank pressure is
continuously monitored using a pressure sensor. The stored Oxygen is delivered to the patient through a
pressure regulator, an externally adjustable flow meter and a microbial filter.
In the beginning, the 230V units, had an orifice built into the purge valve. The
electronically controlled purge valve controls the Oxygen flow timing from one sieve
bed to the other based on the flow meter setting.
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O
HEORY OF
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ECHNICAL
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1039055, VER. 06
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