ELGA
MEDICA-D 7/15 US
Operator Manual
MEDICA-D 7/15 US MANU40550 Version 2
– 05/17
Page 5
3.2 Process Description
The
MEDICA-D 7/15 US
process links six purification technologies,
reverse osmosis, adsorption, ion-exchange, vacuum deaeration,
photo-oxidation and sub-micron filtration. It also incorporates a
recirculation/delivery pump and an optional RO feed water boost
pump.
The unit is designed to operate from a good quality potable water
supply, and produces either 7 or 15 liters per hour of purified reverse
osmosis grade water which is further purified and circulated through a
treated water reservoir. This water is available on demand by the
analyzer at up to 0.6 l/min.
A graphics screen displays the system status and provides control by
means of three function buttons.
The water is processed and treated by the
MEDICA-D 7/15 US
unit as
follows:
Potable water enters through a strainer and inlet solenoid
valve at either regulated mains water pressure, or is pumped
by means of a feed water pump (optional), and passes
through the pre-treatment cartridge. The pre-treatment
cartridge has been designed to protect the reverse osmosis
cartridges from particulate/colloidal matter and excessive
free chlorine, which may be present in the incoming feed
water.
The water then passes the sanitization port and through one
or two reverse osmosis cartridges, set up in series, which
split the flow into permeate and concentrate streams. The
permeate water is further purified whilst the waste
concentrate stream is passed to drain.
The permeate water passes through a water quality sensor
which measures the conductivity of the water.
The permeate water is drawn into the main recirculation
stream by the recirculation pump together with water from
the reservoir and is split into two streams. One stream is
used to provide motive power to an ejector to produce a
vacuum for the degasser before passing to the reservoir.
The second stream passes through the recirculation
purification loop.
The partially purified water then passes through the ion-
exchange cartridge which removes dissolved ionic impurities
from the permeate water.
This water is pumped directly through a degassing chamber
operating under vacuum to reduce levels of dissolved
gasses and then through the UV chamber where it is
exposed to intense UV radiation to provide continuous
bacterial control by photo-oxidation and to promote the
cleavage of organic molecules.
The purified water passes through a 0.2µm filter to remove
any remaining bacteria.
Finally, the water is passed through a:
Water quality sensor, which measures the resistivity of
the water.
Temperature
sensor
which
provides
accurate
temperature measurement.
The delivery of water is controlled by means of a pressure
switch which senses when the analyzer demands water.
During periods of non-use the unit will automatically operate
in intermittent recirculation mode to maintain water purity
with maximum efficiency.
