Retsch DM400 User manual

© Retsch GmbH, 42781 Haan, Retsch-Allee 1-5, Germany 16.12.2021 0001
Operating Manual
DM400 Disc Mill
Translation

Copyright
© Copyright by
Retsch GmbH
Retsch-Allee 1-5
D-42781 Haan
Federal Republic of Germany

Table of contents
4
1Basic structure ..................................................................................................................................7
2Safety and usage instructions .......................................................................................................10
2.1 Requirements for the user.....................................................................................................................10
2.2 Intended use ..........................................................................................................................................11
2.2.1 Operating principle ...........................................................................................................................11
2.3 Duties of the operating company...........................................................................................................12
2.4 Hazard warnings and symbols used......................................................................................................13
2.5 Device safety instructions......................................................................................................................16
2.6 Safety equipment...................................................................................................................................18
2.7 Danger areas..........................................................................................................................................19
2.8 Electrical safety......................................................................................................................................20
2.8.1 General information...........................................................................................................................20
2.8.2 Protection against restarting.............................................................................................................21
3Technical data .................................................................................................................................23
3.1 Dimensions ............................................................................................................................................23
3.2 Weight....................................................................................................................................................23
3.3 Operating noise......................................................................................................................................23
3.4 Voltage, power consumption, power input ...........................................................................................23
3.5 Fuse........................................................................................................................................................23
3.6 Material..................................................................................................................................................24
3.7 Final refinements...................................................................................................................................24
4Installation ......................................................................................................................................25
4.1 Transport...............................................................................................................................................25
4.2 Unpacking ..............................................................................................................................................25
4.3 Positioning.............................................................................................................................................26
4.4 Ambient conditions ...............................................................................................................................27
4.5 Electrical connection .............................................................................................................................28
4.5.1 Adjusting the disc mill to the mains network ...................................................................................28
4.6 Commissioning ......................................................................................................................................28
4.7 Initial switch-on/function test...............................................................................................................29
4.7.1 Switching on......................................................................................................................................29
4.7.2 Switching off......................................................................................................................................29
5Working with the disc mill .............................................................................................................31
5.1 Display and control panel ......................................................................................................................32
5.2 Menu navigation ....................................................................................................................................32
5.3 Specifying the zero point .......................................................................................................................34
5.4 Adjusting the gap width.........................................................................................................................35
5.5 Reverse operation..................................................................................................................................36
5.6 Adjusting the grinding time...................................................................................................................36
5.7 Changing the language...........................................................................................................................37
5.8 Grinding with zirconium oxide grinding discs ......................................................................................37
5.9 Material feed..........................................................................................................................................38
5.10 Sample removal .....................................................................................................................................40

Table of contents
5
5.11 Final refinements ...................................................................................................................................40
6Cleaning .......................................................................................................................................... 41
6.1 Extracting dust after grinding................................................................................................................41
6.2 Grinding chamber ..................................................................................................................................41
6.3 Housing ..................................................................................................................................................42
6.4 Cleaning the hopper...............................................................................................................................42
7Servicing.......................................................................................................................................... 43
7.1 Grinding discs ........................................................................................................................................44
7.2 Replacing the grinding discs .................................................................................................44
7.3 Replacing the gear oil.............................................................................................................................50
7.3.1 Conducting the gear oil change .........................................................................................................50
7.4 Clean suction filter .................................................................................................................................51
8Repair work..................................................................................................................................... 53
8.1 Error display ..........................................................................................................................................53
8.2 Checklist for troubleshooting ................................................................................................................55
9Disposal ........................................................................................................................................... 57
10 EC Declaration of Conformity ....................................................................................................... 58
11 Index................................................................................................................................................ 61

Table of contents
6

Basic structure
7
1Basic structure
1
2
12
10
6
13
3
9
5
4
11
7
8
14

Basic structure
8
1
Display
2
Control panel
3
Main switch
4
Fill hopper
5
Fixed grinding disc
6
Moving grinding disc
7
Gap set screw
8
Closing mechanism of the grinding chamber
9
Locking bolts sample material container
10
Sample material container
11
Suction flange lid
12
Height adjustable support
13
Interlock switch
14
Housing cover

Basic structure
9
a
+ button (change parameters and gap width, menu navigation)
b
- button (change parameters and gap width, menu navigation)
c
Arrow up button (menu navigation)
d
Arrow down button (menu navigation)
e
Start button
f
Stop button
g
Button dust extraction (on/off)
h
Unlocking and locking the grinding chamber
i
Sensor of the grinding chamber
a
b
c
d
e
f
g
h
i

Safety and usage instructions
10
2Safety and usage instructions
2.1 Requirements for the user
This Operating Manual is intended for persons commissioned
with the operation and monitoring of the DM400. The Operating
Manual, and in particular the safety instructions, must be ob-
served by all persons working on or with the equipment. Fur-
thermore, the regulations and provisions on accident prevention
applicable at the application site must be observed. The Operat-
ing Manual must always be kept where the DM400 is used.
Persons with health disorders or who are under the influence of
medication, drugs, alcohol or extreme tiredness must not operate
the device.
The DM400 may only be operated by authorised persons and ser-
viced and repaired by trained specialists. Technically qualified
personnel must conduct all maintenance, servicing and repair
work! Qualified personnel are people who have been authorised
by persons responsible for the safety of the system to execute the
required activities and are able to recognise potential dangers
and avoid them based on their training, experience and instruc-
tion, as well as their knowledge of relevant standards, regulations,
accident prevention regulations and operating conditions (defini-
tion of skilled personnel according to IEC 364).
The instructions in this Manual should be followed in order to
prevent any danger to the user.
In case of any faults, which can impair the safety of persons, the
DM400 or other material assets should be rectified immediately.
The following instructions serve both personal safety of operating
staff and the safety of the described products as well as connect-
ed equipment: all maintenance and repair work may only be car-
ried out by technically qualified personnel!
This Operating Manual is not a full technical description. It only
describes information required for safe operation and mainte-
nance of serviceability.
Retsch has prepared and checked this Operating Manual very
carefully. However, no liability can be assumed in terms of com-
pleteness and accuracy.
Subject to technical modifications.

Safety and usage instructions
11
2.2 Intended use
The DM400 is a disc mill for batch or continuous fine grinding of
hard brittle to medium hard solids from the areas of mining and
metallurgy, geology and mineralogy and the glass and ceramics
industry.
The maximum feed size is 20 mm edge length; the achievable
final fineness level depending on the gap width set is approx. 12
mm (largest gap width) and 0.05 mm (smallest gap width).
The material throughput of the disc mill lies in the range of 20 to
150 kg/h. This depends on the setting of the outlet gap and the
bulk weight and grinding conduct of the sample.
2.2.1 Operating principle
The grinding of the material sample takes place in a grinding
chamber which is dustproof to the outside and in which two
coarsely toothed grinding discs operate against each other. The
moving grinding disc is driven by a powerful, slow running gear
motor.
The sample material is filled through a lockable hopper into the
centre of the upright grinding disc and, after being ground by
compression and shear stress, escapes through the gap between
the two discs. The gap width determines the mean particle size of
the sample material. The grinding gap can be set to an accuracy
of 0.05 mm by using the plus/minus buttons on the control panel.
The gap width can be read off the display (1).
When grinding batches, the sample material is collected in a sam-
ple material container placed in the device (volume: 2l). The
closed design prevents dust escaping. A dust extraction device
may additionally be connected. To clean, the front housing is
opened sideways - the grinding chamber is then freely accessible.

Safety and usage instructions
12
2.3 Duties of the operating company
This Manual should be read and understood before using the
DM400. Use of the DM400 demands expert knowledge and
should be limited to commercial users.
Operating personnel must be familiar with the contents of the
Operating Manual. It is therefore very important for this Operat-
ing Manual to be actually handed to these persons. It must be
ensured that the Operating Manual always remains with the de-
vice.
The DM400 may be used exclusively within the possible uses set
out in this Manual and within the specified regulations in this
Manual. In the event of contravention or incorrect use, the cus-
tomer assumes full liability for the functionality of the DM400 or
for damage arising from an infringement of this duty.
Through use of the DM400 the customer agrees and recognises
that defects, faults or errors cannot be entirely ruled out. In order
to avoid the risk of personal injury or damage to property arising
from this or otherwise or of other indirect or direct damage, cus-
tomers must take adequate and comprehensive safety measures
when working with the device.
It is not possible for Retsch GmbH to monitor compliance with this
Manual or the conditions and methods used in the installation,
operation, use and servicing of the DM400. Damage to property
leading to danger to persons may result from incorrect installa-
tion. We therefore assume no responsibility and liability at all for
loss, damage or costs arising from or in any way associated with
faulty installation, incorrect operation or from incorrect use and
servicing.
The applicable accident prevention regulations must be complied
with.
Generally accepted statutory and other binding regulations on
environmental protection must be observed.

Safety and usage instructions
13
2.4 Hazard warnings and symbols used
Safety instructions
Safety instructions are indicated in this Manual by symbols. The
safety instructions are introduced by signal words which express
the degree of danger.
DANGER!
This combination of symbol and signal word indicates
a direct hazardous situation leading to death or
serious injuries if it is not avoided.
WARNING!
This combination of symbol and signal word indicates
a potentially hazardous situation which can lead to
death or serious injuries if it is not avoided.
CAUTION!
This combination of symbol and signal word indicates
a potentially hazardous situation which can lead to
minor or slight injuries if it is not avoided.
NOTICE!
This combination of symbol and signal word indicates
a potentially hazardous situation which can lead to
damage to property if it is not avoided.
NOTICE!
This combination of symbol and signal word indicates
a potentially hazardous situation which can lead to
damage to the environment if it is not avoided.

Safety and usage instructions
14
Special safety instructions
The following symbols are used in safety instructions to alert to
specific hazards:
DANGER!
This combination of symbol and signal word indicates
a direct hazardous situation through electric current.
If a sign with this symbol is not heeded, serious or
fatal injuries will result.
DANGER!
This combination of symbol and signal word
designates content and instructions for intended use
of the machine in potentially explosive areas. If a sign
with this symbol is not heeded, serious or fatal
injuries will result.
DANGER!
This combination of symbol and signal word
designates content and instructions for intended use
of the machine with flammable materials. If a sign
with this symbol is not heeded, serious or fatal
injuries will result.
DANGER!
This combination of symbol and signal word
designates content and instructions for intended use
of the machine with potentially explosive substances.
If a sign with this symbol is not heeded, serious or
fatal injuries will result.
WARNING!
This combination of symbol and signal word indicates
a direct hazardous situation due to hot surfaces. If a
sign with this symbol is not heeded, skin contact with
hot surfaces may cause serious burns to skin.

Safety and usage instructions
15
WARNING!
This combination of symbol and signal word indicates
a direct hazardous situation due to hot surfaces. If a
sign with this symbol is not heeded, skin contact with
hot surfaces may cause serious burns to skin.
Safety instructions in
operating instructions
Safety instructions may refer to a specific, individual operating
instruction. Such safety instructions are embedded in this operat-
ing instruction in order not to interrupt the flow of reading when
performing the action concerned. The signal words described
above are used.
Example:
1.
Loosen screw.
2.
CAUTION!
Risk of pinching on the lid.
Close the lid carefully.
3.
Tighten the screw.
Tips and recommendations
This symbol highlights useful tips and recommendations
as well as information for efficient and fault-free
operation.

Safety and usage instructions
16
Other labelling
The following labels are used to emphasise operating instructions,
results, lists, references and other elements in this Manual:
Labelling
Explanation
1., 2., 3. ...
Step-by-step operating instructions

Results of operating steps
Lists without specified order
[Button]
Control elements (e.g. button, switch),
indicators (e.g. signalling lamps)
"Display"
Screen elements (e.g. buttons, assign-
ment of function buttons)
2.5 Device safety instructions
Please note!
Only use original accessories and original spare parts. Failure
to do so can place the protection of the machine in doubt.
Safe conduct must be strictly followed during all work.
The currently valid national and international accident
prevention regulations must be observed.

Safety and usage instructions
17
CAUTION!
Wear hearing protection!
Hearing protection should be worn when a noise
level of 85dB (A) is reached or exceeded in order to
prevent damage to hearing.
WARNING!
The maximum workplace concentrations (threshold
limit values - TLV) in valid safety regulations must be
observed, and ventilation must be provided where
necessary or the machine operated under an
extractor hood.
DANGER!
Risk of explosion!
- When grinding oxidable substances (e.g. metals or
coal) there is a risk of spontaneous ignition (dust
explosion) if the fine fraction exceeds a certain
percentage. For this reason special safety
measures must be taken when grinding such
substances and the work must be supervised by a
specialist.
- The device is not designed for use in potentially
explosive areas and is not suitable for grinding
explosive materials.
Do not remove signs.
NOTICE!
Replace damaged or illegible signs without delay.
Unauthorised modifications to the device lead to loss of the
conformity to European directives declared by Retsch and to
loss of the warranty claim.
Only use the DM400 in a technically perfect state and as
intended, with an awareness of safety and dangers as specified

Safety and usage instructions
18
in the Operating Manual. In particular have faults which might
impair safety rectified immediately!
Only use the DM400 in a technically perfect state and as
intended, with an awareness of safety and dangers as specified
in the Operating Manual. In particular have faults which might
impair safety rectified immediately.
2.6 Safety equipment
Safety equipment must be used as intended and must
not be rendered unworkable or removed.
All safety equipment must be checked regularly for
completeness and function.
The disc mill has a comprehensive safety system:
1.
A grille (4G) prevents contact with the fill hopper (4).
2.
A sensor (i) monitors the closing of the grinding chamber
before operation and prevents the disc mill starting up after it
has been opened.
4G
i

Safety and usage instructions
19
3.
A second safety device checks whether the grinding chamber
has been closed by means of the motorised closing mecha-
nism (8).
4.
The interlock switch (13) pulls in the sample material contain-
er after the start of grinding and locks it using the locking
bolt (9) on the container. During operation the interlock
switch monitors whether the device is closed correctly. It
likewise prevents the disc mill starting up after it has been
opened.
The disc mill does not start if the grinding chamber
is open or the sample material container is missing.
2.7 Danger areas
CAUTION!
- Risk of crushing on hopper cover
- Risk of crushing when closing the grinding
chamber
- Risk of crushing when cover of dustextraction is
removed during operation!
8
13

Safety and usage instructions
20
2.8 Electrical safety
2.8.1 General information
The disc mill is switched on/off by means of a main switch (3).
By pressing the switch to I (On):
Disc mill is activated and can be started using the start button
(e) as long as the grinding chamber is closed and the sample
material container is inserted!
By pressing the switch to O (off) during grinding:
The disc mill comes to a halt and is completely deactivated!
Grinding chamber and sample material container remain
locked when switched “off” and cannot be opened.