Prestige PM-D3 Washer Disinfector Section 2
Operating Process ….
Overview
The Prestige PM-D3 Washer Disinfector
uses a microprocessor controlled
operating sequence to alternately spray
accurately measured amounts of
temperature-controlled water from a
rotating spray bar onto items loaded into
purposely designed baskets and
containers, and to flow water through the
centre of hollow instruments connected to
a manifold via Distal Connectors. A
specially formulated detergent gel is
added to the water to clean away fat,
protein, starch, body fluid residue, etc. A
small quantity of scale inhibitor prevents
the formation of deposits on both the items
being cleaned and the component parts of
the washer itself.
Cold water continues to enter the wash
chamber from the mains water supply via
an electronically controlled valve until a
level sensor interrupts and cuts off the
incoming water. If a failure should occur in
the level sensor then a second,
independent sensor will react to cut off the
water supply and prevent overflowing.
Once the wash chamber is filled the pre-
wash stage begins to remove larger
deposits from the load. A pump circulates
water from a sump, cycling it between a
rotating spray bar in the base of the wash
chamber and through a docking port which
connects, via a manifold, to the basket
containing hollow instruments. The
pressure of the water passing through this
spray bar causes it to rotate, thereby
assisting even distribution and a constant
flow of water over and around the items to
be cleaned and disinfected. The pressure
of water passing through the hollow
instruments assists in removing deposits
and residue.
The sump, situated in the base of the
wash chamber, contains an element which
is used to heat the water to 43
o
C
(depending on detergent programme
selected) before a further wash
commences. Once complete, the water is
then drained and replaced with fresh water
to perform the first of two rinse stages.
Immediately prior to the second rinse, a
small quantity of scale-inhibitor (AWT
Fluid) is automatically injected into the
rinse water.
If one of the disinfection programmes
(programmes 1 & 2) have been selected
then the unit next heats the water to the
correct temperature. In order to aid
thermal efficiency and to reduce the
overall cycle time, the water is
intermittently circulated within the tank and
through the hollow instruments during the
heating period.
Once the correct temperature is reached
the disinfection cycle begins. The
microprocessor then accurately controls
the temperature of the water via two
independent temperature sensors located
adjacent to the sump. This ensures that
the correct washing and disinfection
temperatures are maintained during the 2
or 10 minute disinfection stages.
If the wash only programme (programme
3) has been selected then the water is
heated to 55
o
C. and a final rinse stage is
completed.
Finally, the circulation pump is driven in
reverse to drain the wash chamber for the
final time. Once the wash chamber is
emptied the LCD Display indicates that the
cycle has been successfully completed. If
for any reason an error was recorded
during the cycle then the washer will
advise this by displaying the message
“cycle failed” at this time. In order to
prevent unclean/non-disinfected items
from being removed prematurely, the
loading door will remain locked until the
failed cycle is acknowledged. Such an
interruption to the cycle will be notified with
a “PROGRAM ABORTED” message.
Each cycle has a unique, sequential
number and contains information
regarding date, time, temperature, and
duration of each stage of the cycle to
afford total trace-ability. Although this
information is retained within the
microprocessor, an RS232 Data Port at
the rear of the washer allows the
connection of an external Thermal Printer
to display the data in printed form.
For details of a suitable printer see page
15.
Issue 1 06/10/2004 25
