Thermo Scientific Variomag MAXI DIRECT User manual

POLY 15
Magnetic Stirrer
Operating Manual
50108213 Issue 02. 2007
TM
MAXI DIRECT
MULTIPOINT 6/15

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Contents
50108213 _02. 200 7 3 Thermo Scientific
Page
User considerations 6
Correct use 6
Incorrect use 6
Pictographs 6
1 Safety considerations 7
2 Equipment description 9
3 Function
10
4 Startup procedure
11
5 Stirring operation
12
5. 1 Stirring vessels
12
5.2 Magnetic stirring bars
13
5.3 Recommended rotation
speed ranges
15
5.4 Stirring
15
5.4.1 Tips on stirring
16
6 Maintenance and
cleaning
17
7 Troubleshooting
19
8 Technical specifications
20
9 Warranty
22

Assembly drawing
Thermo Scientific 4 50108213 _02. 200 7
1 START/STOP key 6 Stirring point
2 key 7 Digital display
3 key 8 Secondary power cable
4 MODE key 9 Power supply unit
5 Magnetic stirrer 10 Mains cable
Figure 1: The MAXI DIRECT magnetic stirrer with bench - top power supply unit.
1 START/ST OP key 7 Digital display
2 key 8 Secondary power cable
3 key 9 Power supply unit
5 Magnetic stirrer 10 Mains cable
6 Stirring points
Figure 2: The POLY 15 magnetic stirrer with bench - top power supply unit
1
2
3
5
6
7
8
9
10
8
9
10
1
2
3
5
6
7
4

Asse mbly Draw ing
50108213 _02. 200 7 5 Thermo Scientific
1 START/STOP key 6 Stirring points
2 key 7 Digital display
3 key 8 Secondary power cable
4 MODE key 9 Power supply unit
5 Magnetic stirrer 10 Mains cable
Figure 3: The MULTIPOINT 6 / 15 magnetic stirrer wit h bench - top power supply unit
1
2
3
4
5
6
7
8
9
10

User considerations
Thermo Scientific 6 50108213 _02. 200 7
U ser considerations
Correct use
The direct - controlled magnetic stirrers MAXI DIRECT , POLY 15 and MULTIPOINT 6
/ 15 are designed for laboratory use to stir liquids. The MAXI DIRECT magnetic
stirrer is fitted with a single stirring point, while the POLY 15 and the MULTIPOINT 6 /
15 can stir several vessels simultaneously.
The stirrers can be employed for chemical, microbiological, biotechnical,
pharmaceutical or medical purposes.
The stirrers are suited to operation in the f ollowing areas:
On the laboratory bench,
In cold chambers,
In laminar flow equipment,
In safety laboratories and sterile rooms.
Incorrect use
The magnetic stirrers MAXI DIRECT , POLY 15 and MULTIPOINT 6 / 15 must not be
operated in hazardous locations.
The stirrers must not be operated in a water bath.
Do not stir or shake flammable liquids with a low boiling point.
The suitability of the direct - controlled magnetic stirrers for use in incubators is limited,
because the stirring power cannot be adjusted as ne cessary. Moreover, the
integrated eletronics heat the magnetic stirrer additionally.
Pictographs
You will find the following pictographs in this operating manual:
DANGER
This sign refers to dangerous voltages.
DANGER
This sign refers to hazardous situations.
Hazards to human life are indicated by "LIFE HAZARD".
CAUTION
This sign indicates danger to equipment and machinery.
INFORMATION
This sign indicates easier working practices.
Indicates an operating step.
Indicates alternatives.

1 Safety considerations
50108213 _02. 200 7 7 Thermo Scientific
1 Safety considerations
For your own safety, you should observe the following safety warning signs.
The warning signs indicate potential sources of danger.
They also inform on how correct action can avert danger. You will find these warning
signs wherever there is a risk of dangerous situations.
DANGER
Supply voltage and supply frequency must be within the range
specified for the power supply unit (9).
The power supply unit (9) must only be connected to an
earthed socket.
DANGER
The magnetic stirrers must not be immersed in water or
cleaning solutions.
DANGER
Defective secondary power cables (8), mains cables (10), or
mains plugs must be replaced only with original parts by the
manufacturer or one of its representatives.
Return the defective power supply unit (9) to our customer
service for repair.
DANGER
Magnetism.
Magnetic or metallic parts (e.g. data carriers, pacemakers,
watches) can be affected by magnetic fields.
Keep such parts away from the magnetic stirrer (5) and the
magnetic stirring bars.
CAUTION
The equipment must not be o perated in hazardous locations
and in a water bath.
CAUTION
Do not place hot stirring vessels on top of the magnetic stirrer
(5).
Maximum temperature: +56 °C.
CAUTION
Permitted ambient conditions:
Cf. Technical specifications.

1 Safety considerations
Thermo Scientific 8 50108213 _02. 200 7
Avoid extreme temperatu re changes.
The power supply unit (9) must not be run in humid rooms, or
set up in water splash zones.
CAUTION
Do not use chlorine- based cleaning agents, cleaning wool,
cleaning agents containing metal parts or ammonium when
cleaning the equipment.
Suc h agents can damage the surface of the equipment.
CAUTION
In case of repair, the equipment must only be opened by an
authorized service agent.
CAUTION
Do not allow AlNiCo5 type magnetic stirring bars to remain in
an alternating magnetic field if they cannot rotate freely. Do not
subject the magnetic stirring bar to a strong inverse magnetic
field. This may result in destruction of the magnetic stirring
bar.
INFORMATION
If you are not using the magnetic stirrer (5) for a longer period
of time, disc onnect it from mains supply. Only then the stirrer
is completely switched off.
INFORMATION
The length of the magnetic stirring bars must not exceed 80 %
of the vessel diameter. In the case of circular and triangular
magnetic stirring bars, the length must not exceed 50 mm. Do
not use cylindrical stirring bars with a center ring, or elliptical
stirring bars with a round cross - section.
INFORMATION
Some magnetic stirring bars (especially triangular bars) may
have a critical resonance frequency at lower rotation speeds.
This may cause the magnetic stirring bar to wander away from
the turning center and carry out periodic oscillations. Avoid
this rotation speed setting when the problem occurs. Quickly
travel through this problem range when adjusting the r otation
speed.

2 Equipment description
50108213 _02. 200 7 9 Thermo Scientific
2 Equipment description
Figure 1 to Figure 3 show the components together with their position numbers.
Number of stirring points (6):
MAXI DIRECT (Figure 1): 1 stirring point
POLY 15 (Figure 2): 15 stirring points
MULTIPOINT 6: 6 stirrin g points
MULTIPOINT 15 (Figure 3): 15 stirring points
Power for the magnetic stirrer (5) is supplied through the power supply unit (9). The
secondary power cable (8) of the power supply unit (9) is connected to the jack at the
back of the magnetic stirre r (5).
The drive and electronic control unit are sealed into the housing of the magnetic
stirrer (2). The housing is completely sealed.
The housing of the magnetic stirrers MAXI DIRECT and MULTIPOINT 6 / 15 is
hermetically encapsulated, as the magnetic drive is enbedded watertight in synthetic
resin inside the housing. This prevents germs from penetrating into the inside of the
magnetic stirrer (5). The magnetic stirrer (5) is cleared for use in safety laboratories
and sterile rooms.
The drive is constru cted without the use of moving parts and therefore completely
wear - free. In contrast to mechanical drives, it will nor generate circulating air between
the housing and the environment.
After a startup time of approximately 15 seconds, all magnetic stirring bars are
synchronized to rotate at the preselected speed. The soft start -up function
guarantees a safe acceleration of the magnetic stirring bars and can be monitored via
the digital display (7). The soft start - up function is switched on when a dot appear s
next to the rotation speed in the digital display (79. As soon as the selected rotation
speed has been reached, the dot in the digital display (79 vanishes.
Stirring vessels and magnetic stirring bars do not fall within the scope of delivery.
POLY 15:
Y ou start and terminate the stirring operation with the START/STOP key (1). The
rotation speed is set with the key (2) and with the key (3). The digital display (7)
shows the currently set rotation speed.
MAXI DIRECT and MULTIPOINT 6 / 15:
Both the MAXI DIRECT magnetic stirrer as well as the MULTIPOINT magnetic
stirrers are additionally equipped with the MODE key (4). You can select either one
of four rotation speeds: 5/10/15/20 W.
You start and terminate the stirring ope ration with the START/STOP key (1). The
digital display (7) shows the mode selected last. You switch to the power display or
the rotation speed display via the MODE key (4). The desired power or rotation
speed can be selected with the key (2) and the key (3).
After selecting the stirring power, the digital display (7) switches automatically to the
rotation speed display after approximately 5 seconds.

3 Function
Thermo Scientific 10 50108213 _02. 200 7
3 Function
The magnetic stirrers MAXI DIRECT , POLY 15 and MULTIPOINT 6 / 15 are used for
chemical, microbiological, biotechnical or medical purposes, e.g.:
Growing microorganisms (e.g. aerating and growing bacteria cultures),
Dissolving nutrient media and solids,
To prevent the settling of suspended matter,
Titration.
The MAX I DIRECT magnetic stirrer is suitable for stirring larger volumes of liquid.
Due to its far - reaching magnetic field, it is suitable for highly viscose media or
samples in which sediments tend to form.
The magnetic stirrers POLY 15 and MULTIPOINT 6 / 15 ca n stir liquids in several
vessels simultaneously.
The magnetic stirrers are well suited to the growing of bacteria cultures outside the
incubator. If a power setting of 20 W is selected, the plates will heat to 10 - 20 K above
the ambient temperature. Heat will accelerate growth. However, the stirrers cannot
be used in incubators.
The MAXI DIRECT and MULTIPOINT 6 / 15 power settings can be adjusted in four
steps (5/10/15/20 watts). Use more power for larger quantities and more viscous
liquids and reduced pow er for long - term operation without heat generation.
You can stir liquids in various shapes of vessel (e.g. Erlenmeyer flasks, beakers). As
the rotation speed can be variably adjusted, liquids can be moved both gently as well
as vigorously mixed.
The stirring vessel contains a magnetic stirring bar. When the stirring vessels are
placed on the stirring points (6), a electromagnetic field will move the magnetic
stirring bars. The drive of the magnetic stirrer is contructed without the use of moving
parts, such as motors, bearings or belts, and is therefore completely wear - free.
You can set the speed in increments of 10 rpm.
Selectable speed range:
MAXI DIRECT and MULTIPOINT 6 / 15 : 80 to 2,000 rpm
POLY 15 : 130 to 990 rpm
The digital display (7) shows the c urrent speed of the magnetic stirring bars. All
magnetic stirring bars will be moving at the same speed. On the MULTIPOINT 6 ,
magnetic stirring bars on neighbouring stirring points (6) will rotate in the same
direction. On the POLY 15 and MULTIPOINT 15 , ho wever, the magnetic stirring bars
will rotate in opposite directions.
The Memory function saves the setting last at switching off the device, even if
disconnected from mains supply for longer periods of time.

4 Startup procedure
50108213 _02. 200 7 11 Thermo Scientific
4 Startup procedure
DANGER
Supply voltage and supply frequency must be within the range
specified for the power supply unit (9). The power supply unit
(9) must only be connected to an earthed socket.
DANGER
Magnetism.
Magnetic or metallic parts (e.g. data carriers, pacemakers,
watches) can be affe cted by magnetic fields.
Keep such parts away from the magnetic stirrer (5) and the
magnetic stirring bars.
CAUTION
The equipment must not be operated in hazardous locations
and in a water bath.
CAUTION
Permitted ambient conditions:
Cf. Technical specifications.
Avoid extreme temperature changes.
The power supply unit (9) must not be run in humid rooms, or
set up in water splash zones.
Connect the secondary power cable (8) of the power supply unit (9) to the
jack at the back of the magnetic stirrer (5).
Connect the mains cable (10) of the power supply unit (9) to the jack at the
back of the power supply un it (9).
Connect the mains plug (10) to the mains socket.
If a germ - free environment is required, accommodate the power supply unit
(9) outside the sterile area.
The magnetic stirrer (5) is now ready for operation.

5 Stirring operation
Thermo Scientific 12 50108213 _02. 200 7
5 Stirring operation
5.1 Stirring vessels
You should use stirring vessels which are circular in shape, and made of glass,
nonmagnetic metal or plastic. Wall thicknesses should be of an even thinness. Flat -
bottomed glass vessels (not concave) and smooth surfaces improve the running
quality of the magn etic stirring bars.
When stirring larger volumes of liquid, you should use stirring vessels having a
relatively small diameter and a thin bottom.
The following table gives examples of suitable stirring vessels, and the available
stirring points. In the case of larger vessels, not every stirring point (6) can be
occupied by a vessel.
Type MULTIPOIN
T 6
MULTIPOINT
15
POLY 15
Stirring vessels Nominal
capacity
Available stirring points
Erlenmeyer flasks
and flat - bottomed
flasks
25 ml
50/100 ml
250/500 ml
1000 ml
6
6
6
6
15
15
8/6
6
Beakers (tall in
shape)
25 ml
50 ml
100/250 ml
600/1000 ml
2000 ml*
6
6
6
6
6
15
15
15
8
6
Centrifuging tubes
Test tubes
Cultivating tubes
15**
Distance between
stirring points (mm)
130 65
*) restricted range of ap plication
**) test tube rack required

5 Stirring operation
50108213 _02. 200 7 13 Thermo Scientific
5.2 Magnetic stirring bars
Thermo recommends the following magnetic stirring bars:
Type Size (mm) Material Order No.
KOMET 15
KOMET 30
KOMET 50
(Ø x L) 9 x 15
(Ø x L) 12 x 30
(Ø x L) 21 x 50
SmCo
50087924
50087930
50087909
INFORMATION
The length of the magnetic stirring bars must not exceed 80 % of the
vessel diameter. In the case of circular and triangular magnetic
stirring bars, the length must not exceed 50 mm. Do not use
cylindrical stirring bars with a center ring, o r elliptical stirring bars
with a round cross - section.
INFORMATION
Some magnetic stirring bars (especially triangular bars) may have a
critical resonance frequency at lower rotation speeds. This may cause
the magnetic stirring bar to wander away from th e turning center and
carry out periodic oscillations. Avoid this rotation speed setting when
the problem occurs. Quickly travel through this problem range when
adjusting the rotation speed.

5 Stirring operation
Thermo Scientific 14 50108213 _02. 200 7
Thermo has developed a new magnetic stirring bar KOMET (Figur e 4). It contains a
high - quality super - strong samarium - cobalt magnet. KOMET shows a strong magnetic
force. The stronger attraction to the magnetic alternating field provides the stirring bar
with very efficient stirring properties. Even if there are greate r distances (e.g. in high
measuring cylinders) the stirring force will be maintained. The stability of the stirring
bar will not be impaired if the vessel has a curved bottom. The strong magnetic
coupling in samarium - cobalt magnets will also increase friction. The standard design
of the KOMET magnetic stirring bar is therefore unsuitable for stirring liquids
containing particulate matter (such as mud) or for stirring in vessels with a rough
interior surface. Some of the KOMET stirring bars are specially fit ted with a wear -
resitant glide ring for use under excruciating circumstances, such as when stirring
vessels feature rough plastic or stainless - steel bottoms or if the media to be stirred
contain solids (Figure 5).
Any risk of demagnetization by external m agnetic fields is completely eliminated. All
KOMET series stirring bars can be readily recognized by their two conical ends.
Figure 5: KOMET stirring bar
Side view (left) and cross - section through central portion (right)
Figure 6: KOMET stirrin g bar with glide ring

5 Stirring operation
50108213 _02. 200 7 15 Thermo Scientific
5.3 Recommended rotation speed ranges
We recommend the following rotation speed ranges for various applications:
Application Speed range
Microbiological and biotechnical applications: (rpm)
Aeration of bacteria cultures
Growth of bact eria cultures
Dissolving nutrient media, intensive aeration of
bacteria cultures
200 - 350
300 - 450
350 - 500
Routine laboratory work:
Prevent accretion of suspended matter
Titration
Dissolving solids
150 - 250
250 - 400
350 - 700
5.4 Stirring
CAUTION
Do not place hot stirring vessels on top of the magnetic stirrer (5).
Maximum temperature: +56 °C.
Fill stirring vessels no more than half full (high rotation speed range), or
three - quarters full (low rotation speed range).
Place a magnetic sti rring bar into every stirring vessel.
Centre the stirring vessel onto the stirring point (6).
Press the START/STOP key (1).
The magnetic stirrer has a soft - start feature that first centres the magnetic stirring
bars within th e vessels and then slowly accelerates them to the desired speed.
MAXI DIRECT and MULTIPOINT 6 / 15:
With these magnetic stirrers you have a choice of four different stirring power settings
(5/10/15/20 watts). After startup, the digital display (7) shows th e Mode setting last
selected.
Press the MODE key (4).
The digital display (7) shows the set power (e.g. P 20 => 20 watt).
Set the desired power with the key (2) and with the key (3).
After the stirring power has been selected, the digital display ( 7) changes
automatically to the rotation speed selection after approximately 5 seconds.
MAXI DIRECT, POLY 15 and MULTIPOINT 6 / 15:
Set the desired rotation speed with the key (2) and with the key (3).
The digital display (7) shows the currently set rotation speed. You can set the speed
in increments of 10 rpm.
Selectable speed range:
MAXI DIRECT and MULTIPOINT 6 / 15 : 80 to 2,000 rpm
POLY 15 : 130 to 990 rpm

5 Stirring operation
Thermo Scientific 16 50108213 _02. 200 7
End stirring operation:
Press the START/STOP key (1).
The magnet ic stirrer switches to standby. The digital display (7) goes out and the
magnetic stirring bars are stopped. However, the device is still live.
INFORMATION
If you are not using the magnetic stirrer (5) for a longer period of time,
disconnect it from mains supply. Only then the stirrer is completely
turned off.
5.4.1 Tips on stirring
If rotation of the magnetic stirring bar is uneven or jerky:
Reaction between the alternating magnetic field and the magnetic stirring bar is
too strong .
Increase the rotation speed, or
Reduce power, or
Use a smaller magnetic stirring bar.
If the magnetic stirring bar cannot be centred, or constantly wanders off
centre:
Reaction between the alternating magnetic field and the magnetic stirring bar
too weak , or the base of the stirring vessel is concave or too thick.
Move the stirring vessel a little back and forth and recentre it on the stirring
point (6).
Reduce the rotat ion speed, or
Increase power, or
Use a longer magnetic stirring bar or one with a larger diameter (e.g. the
elliptical or KOMET magnetic stirring bar), or
Use a smaller stirring vessel with a thin - walled, flat base, or
Reduce the filling level in the stirr ing vessel.
If the stirring action is too weak:
Increase power, or
Use a magnetic stirring bar of the KOMET series, or
Use a longer magnetic stirring bar, or a stirring vessel of smaller diameter.

6 Maintenance and clean ing
50108213 _02. 200 7 17 Thermo Scientific
6 Maintenance and cleaning
DANGER
The magnetic stirrers must not be immersed in water or cleaning
solutions.
CAUTION
Do not use chlorine- based cleaning agents, cleaning wool, cleaning
agents containing metal parts or ammonium when cleaning the
equipment.
Such agents can damage the surface of the equipment.
The magnetic stirrer (5) is maintenance - free.
The magnetic drive of MAXI DIRECT and MULTIPOINT 6 / 15 is enbedded
watertight in synthetic resin inside the housing. This prevents germs from being
carried over to the inside or the outside. The stainless steel surface is largely
resistant to acids and alkalis.
The standing surface is coated with a protective film. You may leave this on the
magnetic stirrer (5), or strip it off.
Clean the surfaces of the magnetic stirrer (5) with a moistened cloth at regular
intervals.
For this purpose you can use:
water containing a surfactant detergent additive,
isopropanol.
Switch the magnetic stirrer (5) to standby with the help of the START/STOP
key (1). The d igital display (7) disappears.
Disconnect the secondary power cable (8) from the magnetic stirrer (5).
Clean the surfaces of the magnetic stirrer (5).
DANGER
Defective secondary power cables (8), mains cables (10), or mains
plugs must be replaced only with original parts by the manufacturer or
one of its representatives.
Return the defective power supply unit (9) to our customer service for
repair.
CAUTION
In case of repair, the equipment must only be opened by an authorized
service agent.

6 Maintenance and cleaning
Thermo Scientific 18 50108213 _02. 200 7
In case of necessity to repair the equipment, it should be returned to an authorized
servicing agent. The equipment must be clean and free from harm ful substances.
To avoid transport damages during the shipment, please send the equipment
correctly packed in the original packing.
Please always enclose the filled out return delivery note.
If necessary ask for the return delivery note at Thermo (addre ss: see inside of the
cover sheet).
When ordering spares, please state equipment type and serial number.
You can obtain further technical documents (e.g. circuit diagrams, board data) for
your engineers by contacting the address on the inside of the cover sheet.

7 Troubleshooting
50108213 _02. 200 7 19 Thermo Scientific
7 Troubleshooting
Rotation of the magnetic stirring bar is always irregular:
It is unavoidable that magnetic stirring bars will age with time, for example
through sterilization, use at excessive temperatures, or mechanical stre ss (such
as when you drop it). This may adversely affect the magnetic properties of the
stirring bar.
CAUTION
Do not allow AlNiCo5 type magnetic stirring bars to remain in an
alternating magnetic field if they cannot rotate freely. Do not subject
the ma gnetic stirring bar to a strong inverse magnetic field. This may
result in destruction of the magnetic stirring bar.
Remove and replace the magnetic stirring bar with a new one.
Or:
Use the KOMET series of super - strong magnetic stirring bars offered by
T hermo (see chapter 5.2 ). They are made from high performance
Samarium - Cobalt magnets. Any risk of demagnetization by external magnetic
fields is completely eliminated.
The magnetic stirrer (5) fails to operate:
Check to see whether the power supply unit (9) is delivering voltage.
The power supply unit (9) is fitted with a temperature controlled safety system which
will switch off the power supply unit (9) permanently in an overload situation.

8 Technical specifications
Thermo Scientific 20 50108213 _02. 200 7
8 Technical specifica tions
Type MAXI
DIRECT
POLY 15 MULTIPOIN
T 6
MULTIPOINT
15
Order No. 50094711 50094596 50093557 50093538
Stirring points 1 15 6 15
Distance
between stirring
points
mm
- 65 130 65
Stirring volume ml 1 5.000 1 800 1 3.000 1 3.000
Stirring po wer W 5/10/15/20 10 5/10/15/20 5/10/15/20
Rotation speed
range
rpm 80 2.000 130 990 80 2.000 80 2.000
Speed
regulation for
alternating
loads
none
Dimensions
(W x D x H)
mm
180 x 215 x
35
240 x 420 x
35
240 x 420 x
35
240 x 420 x
35
Weight kg 2.5 6 7.5 7.5
Housing Stainless
steel
Stainless
steel,
powder -
coated
Stainless
steel
Stainless steel
Permissible
operating
conditions +5
°C to +40 °C at max. 95 % relative humidity
Permissible
storage
conditions
- 40 °C to +70 °C at 10 % to 95 % rel ative humidity
500 to 1,060 hPa barometric pressure
Operating
voltage
VD
C
24 24 24 24
Protective
system (EN
60529)
IP 62 IP 32 IP 62 IP 62
Equipment
construction
according to IEC 1010