Title of Invention

METHODS FOR OPERATING A ROLLER GRINDING MILL AND PRODUCTION OF CEMENT IN A COMBINED PLANT

Abstract The invention relates to a method for operating a roller grinding mill (2) having a milling chamber (3) in which on a rotary milling surface (5) six milling rollers (6a to 6f) are rolling, the six milling rollers (6a to 6f) are arranged such that they can be swung out pairwise and a 3 x 2 roller mill is formed, that a continuous availability of four milling rollers is ensured for a four-roller operation and that the roller grinding mill (2) is constructed in such a way that with the four milling rollers in a four-roller operation 80% of the full milling capacity of the roller grinding mill (2) is provided.
Full Text The invention relates to a safety system for a roller grinding
mill according to the preamble of claim 1, a method for operating
a roller grinding mill according to the preamble of claim 5 and a
method for the production of cement according to the preamble of
claim 8.
It is known to use roller mills for grinding the most varied
materials. DE 105 099 C discloses a roller carriage arm with a
ring of milling rollers arranged over a rotary milling table and
which has a frame and stands mounted pivotably on said frame. The
milling rollers are resiliently mounted in the stands and can be
moved outwards together with the stands and further parts fixed
thereto.
DE 198 26 324 C discloses a bowl mill with milling rollers, which
are pressed onto the milling pan by means of pressing pieces,
pressing frames and the like. In each case two milling rollers
are successively circumferentially arranged and held on a joint,
multipart holder.
DE 153 958 C discloses a cone mill, in which there are eight
milling cones under spring pressure on a rotating milling pan and
which are mounted outside said milling pan. The milling cones can
be brought individually from a horizontal milling position into a
vertical position for inspection, replacement and similar
purposes.
DE 197 02 854 A1 describes a method and a roller mill. Unlike in
the case of roller grinding mills for crushing mineral material,


such as e.g. a cement raw material, cement clinker and the like,
where the drive capacity for the crushing activity is brought
about by a single drive mechanism with drive motor and gear for
the rotary driving of the milling pan, the milling rollers rolling
on a milling pan are driven directly and have their own rotary
drive, operational fluctuations between the individual rotary
drives of the milling rollers being compensated by a joint load
compensating control. Three or four milling rollers are provided
and if damage occurs to one milling roller or to the rotary drive
a single milling roller can be moved out of the mill casing or the
rotary drive thereof can be repaired or replaced, whereas the
remaining two or three milling rollers continue to operate.
DE 21 66 219 A discloses a roller grinding mill with a mill gear
for the milling pans and pivotably mounted milling rollers rolling
thereon, each roller being individually mounted on a load bearing
pedestal. A particularly advantageous solution for a rapid,
simple pivoting out of the rocking lever with the milling roller
is described.
Roller grinding mills, particularly air-swept mills, from the
design and control standpoints and also with respect to energy
consumption, environmental behaviour and overall economics offer
significant advantages.
In the cement industry air-swept roller mills are used both for
the production of cement raw powder and also for clinker and coal
crushing. If raw material plants are operated in combination with
rotary kilns and a calcining plant, the kiln waste gases from the
heat exchanger and clinker cooler process can be used for mill
drying and for the pneumatic conveying of the crushed cement raw
material or coal.
Methods for the production of cement in a combined system with a
vertical air-swept, Loesche-type roller mill for the mill drying


of a raw material mixture are described in DE 198 36 323 C2. DE-
AS 23 61 060 discloses, in addition to mill drying of raw powder
in an air-swept roller mill, a cooling milling of cement clinker
in an air-swept roller mill downstream of a rotary kiln.
As a rule two, three and four-roller mills constructed according
to a modular system are used. For the crushing of slags and mixed
cements it is also advantageous to use modified Loesche system
roller mills, which can be referred to as 2 + 2 roller mills or 3
+ 3 roller mills. In the case of such 2+2 and 3+3 roller
mills, use is made of roller pairs, comprising a precompacting
roller, also called a S-roller (slave roller) and a crushing
roller, also called a M-roller (master roller). Thus, in a 3 +3
roller mill there are three crushing rollers and three
precompacting rollers and in each case a precompacting roller is
associated with a crushing roller. As a result of a preparation
and a planned, uniform milling bed formation, a low vibration mill
operation is achieved, so that higher specific milling or crushing
forces are possible leading to an improved product quality (EP 406
644 B1).
In order to ensure the necessary operational safety and
reliability of a cement plant in the case of a continuous rotary
kiln operation through a corresponding mill efficiency, various
safety concepts are known.
In a conventional safety concept two parallel roller mills are
combined with a rotary kiln for raw powder processing in the case
of high kiln efficiency levels. It is inter alia disadvantageous
that the capital expenditure is much higher (approximately 20 to
40%) compared with a combination with a roller mill or a raw
material crushing plant.
In principle, the high availability of the roller mill in the
cement industry permits the most economic combination of a rotary


kiln with a roller mill. In the case of four-roller mills with
rollers supported individually in rocking levers according to the
Loesche system, in conjunction with an adequately high volume flow
it is possible to have a two-roller emergency operation in which
approximately 55 to 60% of the full load production rate and a
correspondingly reduced kiln efficiency are achieved. In the case
of two or three-roller mills it is necessary to shut down the
milling plants.
The object of the invention is to provide a significantly improved
safety system for a roller mill, particularly air-swept mill, as
well as a method for operating a roller mill, particularly an air-
swept mill, and a method for cement production based on such a
roller mill safety system and to ensure an extremely high
operational reliability of the cement plant with relatively
limited capital expenditure.
With regards to the roller mill safety system the object is
achieved by the features of claim 1, with regards to the method
for operating a roller mill by the features of claim 5 and with
regards to the cement production by the features of claim 8.
Appropriate and advantageous developments appear in the subclaims
and the description relative to the drawings.
A fundamental idea of the invention is to so design a roller mill
that it reaches the necessary mill production rate at
approximately 80% of full load.
With regards to the use of a roller mill, e.g. for crushing a raw
material mixture, this means that the cement raw material plant or
the raw powder mill is designed in such a way that it ensures a
twenty four hour operation of the rotary kiln with approximately
80% of full load.


According to the roller mill safety system according to the
invention and the method for operating a roller mill a continuous
availability of at least four milling rollers is ensured by the
provision of more than four milling rollers, said more than four
milling rollers being arranged in pairwise facing manner and
continuously four milling rollers of two milling roller pairs
provide approximately 80% of the full mill capacity in a four-
roller operation.
There are preferably six milling rollers and approximately 80% of
the full mill capacity is achieved in a four-roller operation, so
that on the milling roller side an approximately 100% redundancy
is ensured.
Appropriately each milling roller can be swung out from an
operating position into a service position and the mill casing is
sealed in such a way that four-roller operation is ensured when
milling rollers are swung out.
Advantageously, the in particular six milling rollers are
positioned in accordance with a per se known modular system.
According to said modular system in each case one pedestal and one
rocking lever or rocker arm are provided for supporting a milling
roller, as well as a hydropneumatic spring suspension system for a
milling roller pair, so that with six milling rollers a 3 x 2
roller mill is constructed.
This leads to the advantageous possibility of being able to
further operate the roller mill in the case of breakdowns or
damage to the milling rollers, rocking levers or spring suspension
systems with four milling rollers following a brief stoppage and
swinging out of one milling roller pair, so that 80% of the full
mill capacity can be obtained. During this time the swung out
milling rollers can be repaired or replaced.


The roller mill safety system according to the invention ensures
in continuous manner a full capacity or efficiency of downstream
devices, e.g. a rotary kiln, as a result of a corresponding roller
mill efficiency.
Compared with the known safety concepts, the roller mill safety
system according to the invention is extremely economic and
reliable. The greatest economic advantages occur when using the
inventive safety system in a cement plant operated in combined
form. However, in principle, it can be used in all milling and
crushing methods and also in a central milling plant.
The inventive method for the production of cement in a combined
plant, in which in a cement raw material plant cement raw material
undergoes in a roller mill using milling rollers rolling on a
rotary milling surface and accompanied by the supply of waste
gases from a heat exchanger or cooler process is subject to
milling drying and following classifying and separation of the raw
powder from the raw powder-waste gas mixture in a filter and/or
cyclone is fed to a preheater and precalciner and a rotary kiln, a
roller mill is provided which has more than four milling rollers
in a pairwise facing manner for a milling roller-side, almost 100%
redundancy. The roller mill is designed in such a way that 80% of
the full mill capacity is provided by the four milling rollers.
In order to ensure an extremely high operational reliability
during cement production, advantageously six milling rollers are
associated with a 3 x 2 roller mill and the raw powder undergoes a
milling drying. In accordance with the ...





WE CLAIM
1. A method for operating a roller grinding mill (2) having a milling chamber
(3) in which on a rotary milling surface (5) six milling rollers (6a to 6f) are
rolling,
characterized in that
the six milling rollers (6a to 6f) are arranged such that they can be swung
out pairwise and a 3 x 2 roller mill is formed,
that a continuous availability of four milling rollers is ensured for a four-
roller operation and that the roller grinding mill (2) is constructed in such
a way that with the four milling rollers in a four-roller operation 80% of
the full milling capacity of the roller grinding mill (2) is provided.
2. The method as claimed in claim 1 or 2, wherein
the four-roller operation and 80% of the full milling capacity of the roller
grinding mill (2) are ensured if two milling rollers as milling roller pair (6a,
6d or 6b, 6e or 6c, 6f) are swung out from an operating position into a
service position.
3. The method as claimed in one of the preceding claims, wherein,
the six milling rollers (6a to 6f) are arrange in accordance with the per se
known modular system, in which in each case one pedestal (9) and one
rocking lever (10) is provided for guiding a milling roller (6a to 6f),
together with a hydropneumatic spring suspension system (11) for a
milling roller pair (6a, 6d; 6b 6e; 6c, 6f).





4. The method as claimed in claim 3, wherein,
in the case of breakdown or damage to the milling rollers (6a to 6f),
rocking levers (10) or spring suspension systems (11), the roller grinding
mill (2) is operated with four milling rollers (6b,6e,6c, 6f or 6a, 6d, 6c, 6f
or 6a, 6d, 6b, 6e) and 80% of the full mill capacity following a brief
stoppage and swinging out of one milling roller pair (6a,6d or 6b, 6e, or
6c, 6f) for repair purposes.
5. A method for the production of cement in a combined plant having a
cement raw material plant in which cement raw material (23) undergoes
mill drying in a roller grinding mill (2) with the aid of six milling rollers (6a
to 6f) rolling on a rotary milling surface (5) and accompanied by the
supply of hot gases, particularly waste gases (12) from a heat exchanger
unit (42) and a cooling tower (32), and following classifying and
separation of the raw powder (30) from the raw powder-waste gas
mixture (19) in a cyclone unit (27) and/or a filter (28) is fed via a heat
exchanger unit (42) to a precalciner (41) and/or rotary kiln (40),
characterized in that
the six milling rollers (6a to 6f) are arranged as milling roller pairs
(6a,6d;6b,6e;6c,6f) and a 3 x 2 roller mill is formed and
that the roller grinding mill (2) is designed in such a way that 80% of the
full milling capacity is provided by four milling rollers (6a,6d,6e or
6b,6e,6c,6f or 6a,6d,6c,6f) in a four-roller operation.

6. The method as claimed in claim 5, wherein
the six milling rollers (6a to 6f) are arranged according to the per se
known modular system, one module being in each case formed by a
pedestal (9) with a rocking lever (10), a milling roller (6a to 6f) and a
hydropneumatic spring suspension (11), and wherein, in the case of a
breakdown or damage to a milling roller (6a, to 6f), a rocking lever (10) or
a hydropneumatic spring suspension system (11) or wearing parts of the
milling rollers (6a to 60 the rolling mill (2) is stopped, a rocking lever-
milling roller unit (10, 6a, 6d) is swung out pairwise from the operating
position into a service position and the further operation of the roller
grinding mill (2) takes place with the remaining four milling roller (6b,6e;
6c,6f).
7. The method as claimed in claim 6, wherein
The rocking lever-milling roller units (10, 6a,6d) swung out into the
service position are repaired during the four-roller operation of the roller
grinding mill (2).


The invention relates to a method for operating a roller grinding mill (2) having a
milling chamber (3) in which on a rotary milling surface (5) six milling rollers (6a
to 6f) are rolling, the six milling rollers (6a to 6f) are arranged such that they can
be swung out pairwise and a 3 x 2 roller mill is formed, that a continuous
availability of four milling rollers is ensured for a four-roller operation and that
the roller grinding mill (2) is constructed in such a way that with the four milling
rollers in a four-roller operation 80% of the full milling capacity of the roller
grinding mill (2) is provided.

Documents:

00696-kolnp-2006-abstract.pdf

00696-kolnp-2006-claims.pdf

00696-kolnp-2006-description complete.pdf

00696-kolnp-2006-drawings.pdf

00696-kolnp-2006-form 1.pdf

00696-kolnp-2006-form 2.pdf

00696-kolnp-2006-form 3.pdf

00696-kolnp-2006-form 5.pdf

00696-kolnp-2006-international publication.pdf

00696-kolnp-2006-international search report.pdf

00696-kolnp-2006-pct request form.pdf

00696-kolnp-2006-priority document.pdf

696-kolnp-2006-abstract 1.2.pdf

696-KOLNP-2006-ABSTRACT-1.1.pdf

696-kolnp-2006-abstract.pdf

696-kolnp-2006-amanded claims.pdf

696-KOLNP-2006-CANCELLED PAGES.pdf

696-KOLNP-2006-CLAIMS-1.1.pdf

696-kolnp-2006-claims.pdf

696-kolnp-2006-claims1.2.pdf

696-kolnp-2006-correspondence 1.1.pdf

696-KOLNP-2006-CORRESPONDENCE.1.3.pdf

696-kolnp-2006-correspondence.pdf

696-kolnp-2006-correspondence1.2.pdf

696-kolnp-2006-description (complete).pdf

696-kolnp-2006-description (complete)1.1.pdf

696-KOLNP-2006-DRAWINGS-1.1.pdf

696-kolnp-2006-drawings.pdf

696-KOLNP-2006-EXAMINATION REPORT.1.3.pdf

696-kolnp-2006-examination report.pdf

696-kolnp-2006-examination report1.1.pdf

696-KOLNP-2006-FORM 1-1.1.pdf

696-kolnp-2006-form 1-1.2.pdf

696-kolnp-2006-form 1.pdf

696-KOLNP-2006-FORM 18.1.3.pdf

696-kolnp-2006-form 18.pdf

696-KOLNP-2006-FORM 2-1.1.pdf

696-kolnp-2006-form 2-1.2.pdf

696-kolnp-2006-form 2.pdf

696-KOLNP-2006-FORM 26.1.3.pdf

696-kolnp-2006-form 26.pdf

696-KOLNP-2006-FORM 3.1.3.pdf

696-kolnp-2006-form 3.1.pdf

696-kolnp-2006-form 3.pdf

696-KOLNP-2006-FORM 5-1.1.pdf

696-KOLNP-2006-FORM 5.1.3.pdf

696-kolnp-2006-form 5.pdf

696-KOLNP-2006-FORM-27.pdf

696-KOLNP-2006-GRANTED-ABSTRACT.pdf

696-KOLNP-2006-GRANTED-CLAIMS.pdf

696-KOLNP-2006-GRANTED-DESCRIPTION (COMPLETE).pdf

696-KOLNP-2006-GRANTED-DRAWINGS.pdf

696-KOLNP-2006-GRANTED-FORM 1.pdf

696-KOLNP-2006-GRANTED-FORM 2.pdf

696-KOLNP-2006-GRANTED-LETTER PATENT.pdf

696-KOLNP-2006-GRANTED-SPECIFICATION.pdf

696-KOLNP-2006-OTHERS.1.3.pdf

696-kolnp-2006-others.pdf

696-KOLNP-2006-PETITION UNDER RULE 137.pdf

696-KOLNP-2006-REPLY TO EXAMINATION REPORT.1.3.pdf

696-KOLNP-2006-REPLY TO EXAMINATION REPORT.pdf

696-kolnp-2006-reply to examination report1.1.pdf

696-kolnp-2006-specification.pdf

696-kolnp-2006-specification1.1.pdf

696-kolnp-2006-translated copy of priority document.pdf

abstract-00696-kolnp-2006.jpg


Patent Number 248935
Indian Patent Application Number 696/KOLNP/2006
PG Journal Number 37/2011
Publication Date 16-Sep-2011
Grant Date 12-Sep-2011
Date of Filing 23-Mar-2006
Name of Patentee LOESCHE GMBH
Applicant Address HANSAALLEE 243 40549 DUSSELDORF
Inventors:
# Inventor's Name Inventor's Address
1 LOESCHE, THOMAS HANSSELBECKER STR.4 40882 RATINGEN
PCT International Classification Number B02C 15/04
PCT International Application Number PCT/EP2004/009069
PCT International Filing date 2004-08-12
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 103 42 191.2 2003-09-12 Germany
2 103 43 218.3 2003-09-18 Germany