4.7. Specific
information
for
the
use
of
Sterim-
ixer/Sanimixer in ATEX applications
4.7.1. Use of Sterimixer/Sanimixer in tanks with Ex zone
0 or 1
Mixers are generally defined in the Machinery Directive as
incomplete machinery, which are to be installed in another
machine (hence delivered with Declaration of incorpora-
tion, in accordance with Machinery Directive 2006/42/EC,
Annex IIB). That is how the mixer becomes a machine and
it is then to be assessed by the tank supplier if it is com-
pliant with the regulations regarding safety (Machinery
Directive) and with regards to explosion protection (ATEX
Directive 94/9/EC). Only then can a CE mark be granted.
4.7.2. Magnetic mixers in Ex zones
The magnetic mixer is an assembly, consisting of:
• The atmosphere side components, the weld plate
welded to the bottom of the containment shell and
the drive unit
• The components in the tank, impeller and bushing
unit
The magnetic mixer components inside the tank are not
in an Ex zone, as long as these components are covered by
fluid (the Ex zone is by definition only the gas space above
the fluid). The mixer must therefore be covered with fluid
when in operation.
The mixer must be installed so that when sufficient
coverage is not achieved, the drive is switched off auto-
matically by an interlocking safety circuit.
If the impeller is not rotating, the assembly parts lo-
cated in the tank may also be in Ex zone 0 (e.g. when
emptying). In this operating state, the mixer does not
have its own source of ignition. The mixer shall not be
allowed to restart until the impeller inside the vessel is
properly covered with liquid.
4.7.3. Safety systems
In Ex zone 0, a
double safety system
is to be used. There-
fore, the fluid level in the tank must be monitored by a
measuring system with the ignition prevention level 2
(IPL2). In general, two independent systems (such as level
measurement and limit switch) are used (in Ex zone 1, one
directive-compliant system is sufficient).
Measuring systems with high safety integrity level (SIL)
are to be used.
As an additional security element for Ex zone 0, a speed
sensor is supplied (NAMUR), which measures the actual
speed of the mixing impeller. When the difference be-
tween measured speed and the frequency converter’s set
value speed, exceeds 10 % , the drive is to be disabled
(interlocking). In this case the magnetic field between
the inner and outer magnetic rotor is broken, indicating a
malfunction.
4.7.4. Assessment
Components outside of the tank are in Ex zone 1 (or 2) and
are delivered with the corresponding ATEX declaration
of conformity from the manufacturer (Ex II 2G b/c de IIC
T4).
The ’machine’ (mixer tank) with all hardware mounted
is finally to be assessed with regards to policy compliance
(for Ex zone 0 by a notified body).
4.7.5. General
Only genuine parts from the supplier must be used to
achieve the level of protection stated.
Manufacturer
Roplan AB (a Velcora company)
Skyttbrinksvägen 20
SE 147 39 Tumba
Sweden
Steridose AB (a Velcora company)
Himmelsbodavägen 7
SE 147 39 Tumba
Sweden
www.steridose.com
Type denomination
Sterimixer, Sterimixer-SMMS, San-
imixer
General
This incorporation manual applies to the Sterim-
ixer/Sanimixer fitted in applications covered by the
ATEX directive 94/9/EC. Note that applicable health
and safety regulations with regards to processed me-
dia shall be considered by the end-user. The electrical
motor, gear-box and impeller monitor (optional) shall
be installed and operated as per the manufacturers’
instructions supplied with the Sterimixer/Sanimixer.
Protection class
II 2 G c Tx
Type of protection
EN 13463-1:2001 ’c’ ’k’
Safety zones applicable
Zone 1 & 2
Maximum surface temperature
The maximum surface
temperature of the Sterimixer/Sanimixer is very
much dependant on the temperature of the media
processed by the mixer.
4.7.6. Safety instructions specific to ATEX installations
CAUTION:
Please note that all safety instructions in
other parts of this manual equally apply to ATEX in-
stallations. Please familiarize yourself with all relevant
sections.
General
By design, Sterimixer/Sanimixer bearings are
sliding rotary motion devices. For the proper func-
tion, the bearings depend on the presence of cooling
and lubrication by the process fluids to limit frictional
heat generation. Poor lubrication and poor cooling
of the bearings will cause temperatures in excess of
allowable limits. To prevent this from happening, the
following must be avoided:
• The Sterimixer/Sanimixer operates without any
process fluid in the vessel.
• The Sterimixer/Sanimixer operates with a too
low level of process fluid.
• The Sterimixer/Sanimixer operates at too high
speed.
www.steridose.com
Installation & Operation
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