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Sterilization cycle at 134 °C/304 kPa with fractionated prevacuum
Pressure (kPa)
320
300
280
260
240
220
200
180
t
t
bv2
bv3
160
140
120
t
bv1
100
80
60
40
20
t
t
bd1
bd2
0
0
5
10
15
20
25
Diagram 1: Sterilization cycle at 134 °C / 304 kPa with fractionated prevacuum
e.g. P
Instruments (load up to 8.5 kg),
1
P
Textiles 1 (load up to 8 kg), Textiles 2 (load up to 7.5 kg)
2
Process description:
t
-t
:
The chamber is evacuated to more than 90 % up to 7 kPa. The double
bv1
bd1
wall is preheated to sterilizing temperature. The load still contains "thin
residual air".
t
-t
:
The steam penetrates from all sides up to 170 kPa, "compressing" the
bd1
bd2
residual air within the load. The steam condenses in the marginal zones
as the heat is released to the cooler load.
t
-t
:
The chamber pressure is reduced (7 kPa) and released (170 kPa) sev-
bv2
bd3
eral times. As a result, the condensate inside the chamber evaporates
and another portion of the residual air is evacuated from the chamber.
At the same time, the double wall is heated.
t
-t
:
The sterilizing chamber is heated by inflowing steam until the target
bd3
bp
temperature is reached (304 kPa). Saturated steam is forming inside
the
chamber.
t
-t
:
The sterilizing chamber is completely filled with saturated steam. Micro-
bp
eh
organisms are destroyed by the action of moist heat.
t
-t
:
The chamber pressure is released until 120 kPa is reached, and the
eh
bt
remaining condensate is evacuated. Then the steam is siphoned from
the chamber, causing the pressure to drop and therefore the remaining
condensate to evaporate.
t
-t
:
When 20 kPa are reached, the drying phase starts. Throughout the
bt
et
drying phase, the double wall is maintained at sterilizing temperature.
t
-t
:
The sterilizing chamber is aerated via the sterile air filter.
et
ez
Thermo Scientific
8 Preparing for sterilization
t
= Beginning of the first evacuation phase
t
t
bv1
bp
eh
t
= Beginning of the first steam entry phase
bd1
t
= Beginning of the second evacuation phase
bv2
t
= Beginning of the second steam entry phase
bd2
t
= Beginning of the third evacuation phase
bv3
t
= Beginning of the third steam entry phase
bd3
t
= Beginning of the holding phase
bp
t
= End of the holding phase
eh
t
= Beginning of the drying phase
bt
t
= End of the drying phase
et
t
t
t
bd3
bt
et
30
35
40
45
50
55
60
41
Atmospheric pressure
65
70
75
80
85
90
95
pressure
Time (min)
100
50112712_082007_GB
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