Precision Medical PM4351 EasyFlow5 - Manual (Page 5)

3
Theory of Operation
Air enters the system through the compressor intake muffler/filter (1). The compressor (2) increases the air pressure to
approximately 30 psig (2 Bar). The compressed air is then directed through the dual solenoid valve (4) (see note) to one
of the molecular sieve beds (5 or 6). As compressed air passes through the selected sieve bed, nitrogen is stripped from
the air and a high concentration of oxygen passes through. After a predetermined time, the dual solenoid reverses
operation, and compressed air passes thru the other sieve bed.
Note: The dual solenoid valve is controlled by an electronic circuit board (17) which determines the time interval
for each concentrated oxygen producing cycle. This is based on the demand from the output flow selection of the
dial flow control valve (14).
Inside the bed, concentrated oxygen developed from the molecular sieve beds (5 or 6) splits into two streams. One
stream flows through a check valve (8 or 9) into a product tank (10 and 11) where it is stored for use. This stored
concentrated oxygen is then routed to the point of use by way of a pressure regulator (12), a filter (13), an optional oxygen
sensor (18), and a user selectable dial flow control valve (14). The other stream of concentrated oxygen flows through a
pressure reducing orifice (7) to the other molecular sieve bed (5 or 6) to desorb the nitrogen that was stored in the sieve
from the previous cycle. The desorbed nitrogen flows to atmosphere through the dual solenoid valve (4) and a muffler
(15).
If a situation arises where the system pressure becomes elevated above normal operating pressures at the compressor a
mechanical preset pressure relief valve (3) will relieve this elevated pressure. Also, if the cycle pressure at the product
tank (10 and 11) rises above or falls below the normal operating range an electronic pressure sensor (16) will create an
alarm condition and shut the concentrator down. This system shut down is denoted by an audible alarm (17) along with
an illuminated led (17).