Page 29 of 110 Pages
5. DESCRIPTION OF PROGRAMS
The sterilization cycle has a few stages in order to perform effective sterilization,
i.e. destroying the required amount of bacteria according to the relevant standards.
5.1 Operations sequence
o
Vacuum Pulse (ELPV model only)
At one pulse, vacuum is built down to 25 kPa. Removing air pockets in
the autoclaved material improves the penetration of the steam during
the sterilization stage.
o
Water Inlet (EL/ELPVmodels)
Water is injected into the chamber until the water level electrode
detects that the required level is reached. Some time is added for a
certainty before proceeding to the heating stage.
o
Heat (EL/ELPVmodels)
The autoclave is equipped with band heating elements. After water has
been introduced to the chamber and the unit has been activated, the
heating elements begin to heat. The temperature and pressure in the
chamber increase until appropriate levels are reached. Sensors located
inside the chamber control the temperature and pressure levels.
o
Sterilization (EL/ELPVmodels)
The sterilization temperature is factory set at 134C (273F) for
instruments and at 121C (250F) for liquids and other materials for
which this temperature is appropriate. These settings may be modified
before each cycle. When sterilization temperature is reached, the timed
sterilization cycle begins.
o
Exhaust (EL/ELPVmodels)
When the timed sterilization cycle is complete, the unit enters into the
exhaust stage, provided that a program other than the liquid program
was selected. The steam is exhausted from the chamber, bringing the
internal pressure down to atmospheric pressure.
Note: In the Bio-Hazard cycles (optional for BH, bio-hazard models), all
exhausts from the chamber before completion of the Sterilization
phase are performed through the bio-hazard filter.
o Drying (ELPVmodel only)
Drying stage; vacuum is built up and the coil heats the chamber for
time set in Dry Time parameter.
Vacuum Test Program (ELPV model only)
Vacuum is produced in the chamber down to P
1
=15 kPa. At this stage
all the valves close. The autoclave remains in this stage for 5 minutes.
This period enables the condition in the chamber to reach equilibrium.
After the 5 minutes have elapsed the printer records the pressure that
is referred to as P
2
. At this point the test begins and lasts 10 minutes.
At the end of the test, the printer records the results. The pressure at
the end of the test is referred to as P
3
. The rate of change of P
3
-P
2
shall
not exceed 0.13 kPa/min.).
Note: During the test period the autoclave is not heated.
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