n
Figure 10
SMO-type impeller with openings that ex-
pose the bearing surfaces and weld plate during the clean-
ing cycle.
CORROSIVE AGENTS HAZARD:
Many cleaning
agents are corrosive. Please exercise adequate care
when handling.
4.5.2. Cleaning guidance for SMO/SMMS/Sanimixer-
type impeller
This section provides general guidelines for CIP proce-
dures for Sterimixer with SMO style impellers, Sterimixer
SMMS and Sanimixer.
The bearing assembly on a SMO/SMMS/Sanimixer-
type impeller head is exposed. When directing flow from
a spray ball to the impeller head, the bearing surfaces will
get in contact with the CIP fluid.
The openings on top of the SMO-type impeller head
also allow the CIP fluid to hit the weld-plate under the im-
peller, please refer to Figure 10. In order to hit all surfaces,
the impeller head needs to rotate at low speed during the
CIP cycle (e.g. 100 rpm).
The cleaning procedure can be divided in two steps:
4.5.3. Step 1: CIP solution cleaning
Start CIP solution flow through the sprayball at the rec-
ommended flow rate. Open the tank outlet valve com-
pletely to allow full drainage. Operate mixer at low speed
(around 50-100 rpm).
Ensure that the sprayball flow is hitting the impeller
head. Typically, coverage test with riboflavin (usually
performed during FAT) will provide evidence that the
impeller head is fully wetted by the cleaning solution.
The duration of the cycle depends on the application
and requires to be validated by swabbing vessel and mixer
surfaces.
4.5.4. Step 2: WFI (water for injection) flushing
Repeat step 1 using WFI (water for injection) through the
sprayball.
4.6. Guidance for sterilizing Sterimixer/Sanimixer
The Sterimixer/Sanimixer are designed for optimum per-
formance in steaming in place (SIP) without any need for
dismounting. The selection of method from those listed
below depends on the individual conditions.
CAUTION:
The permanent magnets in the impeller
and the rotor withstand temperatures up to +225
◦
C.
Never expose these parts to higher temperatures. The
drive unit and gearbox shall not be exposed to ambient
temperatures above +40
◦
C.
+
NOTICE:
Use caution when exposing to temperatures
over +135
◦
C
as this may decrease the life expectancy
of the elastomeres used in the bearing assembly.
A certain delay in the rise of temperature between the
inside of the impeller and the vessel is caused by the mass
of the impeller head. This delay is influenced by:
• Sterimixer/Sanimixer size: the larger the Sterim-
ixer/Sanimixer, the longer the delay.
• Sterilization method: steam sterilization gives the
shortest delay. Hot air sterilization gives the longest
delay.
When evaluating sterilization temperature one should
focus on the location that is most likely to have the lowest
temperature (typically this would be on the inside, in the
impeller cavity). A thermal element should be used if the
system is sterilized in a hot air oven or autoclave. For
applications with SIP/SHW where the impeller rotates,
the validation should be carried out by biological tests.
4.6.1. Steaming in place (SIP)
Example of SIP procedure:
• To remove any condensation,the impeller may be ro-
tated at a low speed (i.e. 50 rpm) for a few seconds,
approximately every five minutes.
• When the sterilization temperature in the vessel has
been achieved, the periodic rotation of the Sterim-
ixer/Sanimixer shall be stopped.
4.6.2. Super heated water sterilization in place (SHW)
The vessel and the mounted drive unit are sterilized with
super heated water. Example of SHW procedure:
• The vessel is filled with WFI (water for injection) to a
suitable level.
• During heating, sterilization and cooling the Sterim-
ixer/Sanimixer should rotate.
• Vortices (suction whirlpools) must not arise. The wa-
ter level and speed control this.
• During the emptying phase the Sterimixer/Sanimixer
must not rotate.
4.6.3. Sterilization in autoclave or hot air oven
Dismount the drive unit as per section 3.4.2.
CAUTION:
The vessel and the impeller (without the
drive unit) must be sterilized in an upright position
in an autoclave or hot air oven to prevent the impeller
sliding off the bearing. To prevent this, a magnetic drive
dummy can be installed to avoid any risk of damage
and hold the impeller in place.
10
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