1. FIELD OF THE INVENTION
The present invention relates to an improved leveller bar for coke ovens for
levelling the coal bulk charging cone forming below the charging holes of a coke
oven chamber during the coal charging process, and more particularly to an
improved leveller bar for coke ovens for increasing coke oven charge volume.
The said improved leveller bar comprises stiffners that are inclined at a specified
angle with a reduced height of the said stiffners having welded interconnected
support elements, which can extend over the entire length of the oven chamber,
when inserted inside the oven and which are arranged in parallel to one another
at a distance dependent on the width of the oven chamber.
2. BACKGROUND OF THE INVENTION
Description of the Related Art
There are many patents available that disclose conventional leveller bars.
US2004020413 patent application dated 2004-02-05 to Weiershausen et al
relates to a levelling device with an adjustable width. The said Patent describes a
device for leveling the coal filled in the retort of a coke oven, comprising a leveller
bar connected with a leveller bar drive that can be moved into and out of the
retort through a leveling opening, and performs a leveling movement back and
forth in the retort. According to the invention, the leveller bar has a rake blade on
its front end with a width that can be adjusted by an operating device (6)
arranged in the leveller bar.
US 4,181,578 Patent dated Jan. 1, 1980 to Stauffer delineate a leveller bar for
coke oven. The '578 Patent provides a levelling bar with a pair of longitudinally
extending side members having inner side surfaces upwardly inclined toward
each other and cross plates therebetween wherein such side members and cross
plates form a plurality of coal receiving pockets having a bottom opening larger
than a top opening to minimise arching of coal therein. The cross plates can have
front and back surface which are vertical or upwardly inclined.
CA 2422456 to Thyssen Krupp Encoke GMBH relates to a device for levelling the
coal with which the retort of a coke oven is filled, comprising a leveller bar which
is connected to a leveller drive, which can be moved in and out of the retort
through a levelling opening and which performs a levelling movement back and
forth in the retort The said leveller bar has a rake blade at its front end. The
width of this'rake blade can be adjusted by means of an operating device, which
is located in the leveller bar.
W09629377 dated 1996-09-26 to Thyssen Still Otto GMBH and Dudler Heinz
and US5925222 dated 1999-07-20 to Dudler Heinz talk about a leveller bar for
coke ovens. Both of the patents relate to a leveller bar for coke ovens for
levelling the coal debris cone forming below the filling holes in the furnace
chamber during the filling process. The leveller bar comprises interconnected
support elements which extend over the entire length of the oven chamber and
are disposed parallel to one another at a distance dependent on the width of the
oven chamber. The said leveller bar comprises at least three support elements
which are arranged parallel to one another, extend over the entire length of the
oven chamber and are disposed relative to one another such that the leveller bar
has a triangular cross-section. The two lower support elements are disposed at
the same level and the upper support element is arranged centrally there above
TW561188 dated 2003-11-11 to Montan Technologie GMBH Deutsc describes a
levelling rod for coking furnace to level the coal bulk cone formed under the filing-
holes of the furnace-chamber during the filling procedure, composed of two
substantially vertically arranged side-walls which extend substantially through the
whole length of the furnace-chamber and which are arranged parallel to each
other and connected with each other, separated from each other by a distance
that is dependent from the width of the furnace-chamber, with transversely
standing coal-dogs which are arranged in a row in the intermediate space
defined by the side-walls with distance therebetween; the coal-dogs extend only
through a part of the transverse sectional area of the levelling rod, wherein the
height of the coal-dogs, which occupy the whole side-wall distance is smaller
than the height (H) of the side-wall, and the side walls above the coal-dogs form
a gas channel substantially free of built-in parts.
DE19830382 dated 2002-12-19 to Montan Technologie GMBH Deutsc and
AU755720 dated 2002-12-19 to Montan Technologie GMBH Deutsc relate to a
levelling bar for coking ovens, for levelling the cones of discharged coal that form
under the filling holes of the oven chamber during the filling process. The
levelling bar consists of two cheeks, such as plates, which extend essentially
over the entire length of the oven chamber and which are arranged at a distance
from each other depending on the width of the oven chamber, and parallel to
each other. They are also interconnected and are essentially vertical. The
levelling bar also has transversal coal carriers which are arranged in the
intermediate space delimited by the cheeks at a mutual distance, one behind the
other and which only extend over part of the cross-sectional surface of the
levelling bar formed between the cheeks. The height of the coal carriers, which
take up the entire interval between the cheeks, is less than the height (H) of the
cheeks and the cheeks form a gas channel above the coal carriers, which is
essentially free of built-in components.
DE 40 34 341 C2 describes a prior art leveller bar consisting of vertical metal
plates arranged in a longitudinal oven direction and in parallel to each other, with
there being transverse coal entrainment carriers located at regular distances in
the intermediate space confined by the vertical plates.
Moving of leveller bars of this type into the oven chamber during the coal
charging process usually blocks the oven free space above the coal charge by
approximate 60%. This constraint frequently involves clogging inside the oven
free space by the end of the coal charging process and, associated therewith,
serious emission because the charging gases can no longer be discharged to the
suction point, i.e. to the standpipe or to the gas jumper pipe.
DE-A 10 58 018 describes a leveller bar for coke ovens. The part of the bar
which is movable into the coke oven is provided with two side wings comprising
web-type connection elements arranged at certain distances. The two side wings
are shaped like closed hollow girders with evenly arched sheff plates. Clogging
and emissions as a consequence thereof may occur because of the continuous
lateral metal plates.
IN 142724 dated 1977-08-20 to Otto & Co GMBH Dr C and GB 1455315 dated
Nov 10, 1976 to Simon Carves Limited relates to a device for leveling coal
charges from the chamber of a coking oven. A leveller is supported on a sub-
structure arranged to travel along a battery of ovens and to be inserted through a
port provided in the oven door of each oven chamber. The said device has
means for adjusting height of the base of the leveller port.
The prior patents and patent applications narrated above do not disclose an
improved leveller bar for coke ovens for levelling the coal bulk charging cone
forming below the charging holes of a coke oven chamber during the coal
charging process thereby increasing coke oven charge volume wherein the said
improved leveller bar comprises stiffners that are inclined at a specified angle
with a reduced height of the said strffners having welded interconnected support
elements which can extend over the entire length of the oven chamber. When
inserted inside the oven and which are arranged in parallel to one another at a
distance dependent on the width of the oven chamber.
3. SUMMARY AND OBJECTS OF THE INVENTION
Accordingly, the present invention is directed to propose a new design and
construction for an improved leveller bar making it feasible to increase the coke
oven charge volume.
An object of the present invention is to provide an improved leveller bar for coke
ovens for levelling the coal bulk charging cone forming below the charging holes
of a coke oven chamber during the coal charging process.
Another object of the said improved leveller bar for coke ovens is to increase
coke oven charge volume by compacting coal and minimising spillage during
charging by the said strffners and to retain part of coal, being dragged out and
crossed over the stiffners, inside the oven for further compaction.
Another further object of the said improved leveller bar for coke ovens is to
provide stiffners that are inclined at a specified angle with a reduced height of the
said stiffners having welded interconnected support elements which extend over
the entire length of the oven chamber and which are arranged in parallel to one
another at a distance dependent on the width of the oven chamber.
To achieve these and other advantages and in accordance with the purpose of
the present invention, as embodied and broadly described, the improved leveller
bar for coke ovens for levelling the coal bulk charging cone forming below the
charging holes of a coke oven chamber during the coal charging process thereby
increasing coke oven charge volume, the said improved leveller bar comprising:
(a) a first upstanding longitudinally extending side member having a first side
surface inclined upwardly toward said second side surface;
(b) a second upstanding longitudinally extending side member having a second
side surface;
(d) a plurality of upstanding transversely extending cross plates between said
first and said second side members each cross plate having a substantially
vertical front and back surface;
(e) each pair of cross plates and side members therebetween forming a coal
receiving pocket having a top and bottom opening, with said bottom opening
larger than said top opening to minimize arching of coal within said pocket; and
(f) a leveling head means on one end of said leveling bar for first contacting coal
in a coke oven during leveling
characterised in that
the said plurality of upstanding transversely extending cross plates, i.e., stiffners
are inclined at a specified angle with a reduced height of the said stiffners
having welded interconnected support elements extending over the entire
length of the oven chamber and are arranged in parallel to one another at a
distance dependent on the width of the oven chamber.
The improved leveller bar for coke ovens for levelling the coal bulk charging cone
forming below the charging holes of a coke oven chamber during the coal
charging process thereby increasing coke oven charge volume wherein the
welded interconnected support elements are provided as supporting elements
extending over an entire length of the oven chamber.
The improved leveller bar for coke ovens for levelling the coal bulk charging cone
forming below the charging holes of a coke oven chamber during the coal
charging process thereby increasing coke oven charge volume wherein the said
leveller bar is tapered slightly at front end.
The improved leveller bar for coke ovens for levelling the coal bulk charging cone
forming below the charging holes of a coke oven chamber during the coal
charging process thereby increasing coke oven charge volume wherein the said
leveller bar are made of two strips joined together with the said plurality of
upstanding transversely extending cross plates.
The improved leveller bar for coke ovens for levelling the coal bulk charging cone
forming below the charging holes of a coke oven chamber during the coal
charging process thereby increasing coke oven charge volume wherein the said
two strips are made of special grade steel sheets.
The improved leveller bar for coke ovens for levelling the coal bulk charging cone
forming below the charging holes of a coke oven chamber during the coal
charging process thereby increasing coke oven charge volume wherein the said
the said two strips are joined together by a curved steel plate.
The improved leveller bar for coke ovens for levelling the coal bulk charging cone
forming below the charging holes of a coke oven chamber during the coal
charging process thereby increasing coke oven charge volume wherein the said
leveller bar is slightly tapered at the end.
The improved leveller bar for coke ovens for levelling the coal bulk charging cone
forming below the charging holes of a coke oven chamber during the coal
charging process thereby increasing coke oven charge volume wherein width
and length of the said leveller bars depend on the dimension of levelling window
of the ram side doors and length of coke ovens.
The present invention also describes a coke oven arrangement having improved
leveller bar, comprising:
a ram car;
a coke oven defining a coke oven chamber with charging holes forming a
charging cone below said charging hole, during a coal charging process;
a leveller bar including plurality of upstanding transversely extending cross plates
extending over an entire length of said oven chamber, the said plurality of
upstanding transversely extending cross plates, i.e., stiffners are inclined at a
specified angle with a reduced height of the said stiffners having welded
interconnected support elements extending over the entire length of the oven
chamber and are arranged in parallel to one another at a distance dependent
on the width of the oven chamber.
The various features of novelty that characterise the invention are pointed out
with particularity in the claims annexed to and forming a part of this disclosure.
For a better understanding of the invention, its operating advantages and specific
objects attained by its uses, reference is made to the accompanying drawings
and descriptive matter in which preferred embodiments of the invention are
illustrated.
4. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The invention is described in the following in greater detail by way of an example
with reference to the accompanying drawings in which.
Fig. 1 illustrates two views showing a prior art leveller bar in side elevation front-
end portion and a top plan view of the said leveling bar front-end portion
according to the prior patent US 4,181,578;
Fig. 2 in a longitudinal section shows the arrangement of the leveller bar in the
oven free space of a coke oven chamber according to the prior patent
US 5,925,222;
Fig. 3 depicts an conventional leveller bar of Steel Authority India Limited (SAIL)
in side elevation front-end portion and a top plan view of the said leveling bar
front-end portion; and
Fig. 4 shows the improved leveller bar for coke ovens according to the present
invention illustrating in side elevation front-end portion and a top plan view of the
said leveling bar front-end portion.
5. DESCRIPTION OF THE PREFERRED EMBODIMENT
Conventional leveller bar like US 4,181,578 Patent dated Jan. 1, 1980 to Stauffer
has been described in Fig. 1. The leveling bar of Fig. 1 includes upstanding,
longitudinally extending, downwardly tapered side members 29 and 31 spaced in
substantially parallel relation. Side member 29 has a first inner side surface 33
upwardly inclined, as an outer side surface (not shown in Fig. 1) shown
substantially vertical, or not inclined.
FIG. 2 illustrates the top of the oven 5, the charging holes 6, the standpipe 8 and
the coke oven door 7. A leveller door opening is located in the upper area of the
coke oven door 7 on the pusher side. Through this leveller door opening the
leveller bar 10 can be moved in horizontally and longitudinal directions into the
oven free space floor for the coal levelling process. This conventional leveller bar
comprises two lower supporting elements 11 which are arranged at the same
level and are arranged in parallel to each other. These supporting elements 11
are interconnected at regular distances through horizontally arranged transverse
braces (not shown in the Fig. 2). Arranged centrally above the transverse brace,
there is provided an upper supporting element 12. The upper supporting element
12 is connected with the two lower supporting elements 11 through the
connecting braces 14. For stabilization, the two lower supporting elements 11 are
connected to the upper supporting element 12 that is connected with the
diagonally extending supporting brace 15. Each supporting brace 15 is affixed at
connection points of the supporting elements 11 with the transverse braces
and/or affixed at the upper supporting elements 12 with the connecting braces
14.
The existing leveller bars (102), shown in Fig. 3, are made of two steel strips
(100, 103) joined together with vertical stiffners (101). The width and length of
leveller bars depends on the dimension of levelling window of the ram side doors
and length of coke ovens (not shown in Fig. 3). The leveller bar (102) is tapered
slightly at front end and the two strips (100, 103) are joined together by a curved
steel plate. The leveller bar (102) is slightly tapered at the rear-end also.
As these conventional leveller bars consist vertical stiffners (101), these leveller
bars tend to drag out coal during their drawback motion. The quantity of coal
charged in oven gets reduced using these conventional stiffners (101) as the
amount of coal taken in charging cars is fixed. Moreover, in its forward motions,
the existing leveller bar (102) only pushes the coal forward but does not
compress the coal. Therefore, the compactness of top layer of coal charge in
oven is not increased
According to the present invention, as illustrated in Fig. 4, an improved leveller
bar (202) for coke ovens for increasing coke oven charge volume is provided.
The design of the stiffners (201) of the said improved leveller bar (202) is such
that it reduces the dragging out of coal charge during its backward motion inside
the coke oven. These stiffeners (201) are inclined at an angle, as against
conventional vertical stiffners (101) in existing leveller bars (102). Moreover, the
height of the stiffners (201) is reduced to get the said benefit. These stiffners
(201) don't drag out all the coal, rather compact the coal and part of coal being
dragged out crosses over the stiffners (201) and remains inside the oven for
further compaction. Therefore, spillage during charging in the improved leveller
bar (202) is less and coal charged inside the coke oven is more. Further, the said
improved leveller bar (202) has the following components to facilitate the levelling
of the coke bulk charging cone forming below the charging holes of a coke oven
chamber during the coal charging process thereby increasing coke oven charge
volume:
(a) a first upstanding longitudinally extending side member (200) having a first
side surface inclined upwardly toward said second side surface;
(b) a second upstanding longitudinally extending side member (203) having a
second side surface;
(d) a plurality of upstanding transversely extending cross plates (201) between
said first (200) and said second side members (203) each cross plate (201)
having a substantially vertical front and back surface;
(e) each pair of cross plates (201) and side members (200, 203) there between
forming a coal receiving pocket having a top and bottom opening, with said
bottom opening larger than said top opening to minimize arching of coal within
said pocket; and
(f) a leveling head means on one end of said leveling bar (202) for first contacting
coal in a coke oven during leveling.
5.1 INDUSTRIAL EXPERIMENTATIONS AND OBSERVATIONS
As the design of stiffners (201) in improved leveller bar (202) facilitates
compactness of top layer of coal charge and reduction of dragged out coal, coal
charged per oven is increased with the use of improved leveller bars (202).
These improved leveller bars (202) have been introduced in ram cars of coke
ovens at SAIL's Durgapur Steel Plant, West Bengal, India. Industrial trials have
been conducted in a particular battery for a particular ram car using both
conventional (102) and improved leveller bars (202). A number of observations
have been taken in many ovens and in each observation, coal charge height
under each of the four charging holes has been measured along with amount of
coal spillage during charging. From the said observation, the average charge
heights and weights of spillage coal for both the existing (102) and improved
leveller bars (202) are presented in Table 1. ft is seen from Table 1 that average
charge height has been increased by 48 mm in case of improved leveller bar
(202) usage. The dragging out of coal as spillage has also been reduced
significantly by 119 kg per charging for this case.
While specific embodiments of the invention have been shown and described in
detail to illustrate the application of the principles of the invention, it will be
understood that the invention may be embodied otherwise without departing from
such principles.
We Claim:
1. An improved leveller bar (202) for coke ovens for levelling the coal bulk
charging cone forming below the charging holes of a coke oven chamber during
the coal charging process thereby increasing coke oven charge volume, the said
improved leveller bar (202) comprising:
(a) a first upstanding longitudinally extending side member (200) having a first
side surface inclined upwardly toward said second side surface;
(b) a second upstanding longitudinally extending side member (203) having a
second side surface;
(d) a plurality of upstanding transversely extending cross plates (201) between
said first (200) and said second side members (203) each cross plate (201)
having a substantially vertical front and back surface;
(e) each pair of cross plates (201) and side members (200, 203) there between
forming a coal receiving pocket having a top and bottom opening, with said
bottom opening larger than said top opening to minimize arching of coal within
said pocket; and
(f) a leveling head means on one end of said leveling bar (202) for first contacting
coal in a coke oven during leveling
characterised in that
the said plurality of upstanding transversely extending cross plates (201), i.e.,
stiffners (201) are inclined at a specified angle with a reduced height of the said
stiffners (201) having welded interconnected support elements extending over
the entire length of the oven chamber and are arranged in parallel to one
another at a distance dependent on the width of the oven chamber.
2. The improved leveller bar (202) as daimed in claim 1 wherein the said support
elements are provided as supporting elements extending over an entire length of
the oven chamber.
3. The improved leveller bar (202) as claimed in claim 1 wherein the said leveller
bar (202) is tapered slightly at front end.
4. The improved leveller bar (202) as claimed in claim 1 wherein the said leveller
bar (202) are made of two strips (203, 203) joined together with the said plurality
of upstanding transversely extending cross plates (201).
5. The improved leveller bar (202) as claimed in claim 1 wherein the said two
strips (200, 203) are made of special grade steel sheets.
6. The improved leveller bar (202) as claimed in claim 1 wherein the said the said
two strips (200, 203) are joined together by a curved steel plate.
7. The improved leveller bar (200) as claimed in claim 1 wherein the said leveller
bar (202) is slightly tapered at the end.
8. The improved leveller bar (202) as claimed in claim 1 wherein width and length
of the said leveller bars (202) depend on the dimension of levelling window of the
ram side doors and length of coke ovens.
9. A coke oven arrangement having the improved leveller bar (202) as claimed in
claims 1 to 8, comprising:
a ram car;
a coke oven defining a coke oven chamber with a charging hole forming a
charging cone below said charging hole, during a coal charging process; and
a leveller bar (202) including plurality of upstanding transversely extending cross
plates (201) extending over an entire length of said oven chamber, the said
plurality of upstanding transversely extending cross plates (201), i.e., stiffners
(201) are inclined at a specified angle with a reduced height of the said stiffners
(201) having welded interconnected support elements extending over the entire
length of the oven chamber and are arranged in parallel to one another at a
distance dependent on the width of the oven chamber.
10. An improved leveller bar for coke ovens, substantially as herein described,
particularly with reference to and as illustrated in the accompanying drawings.
11. A coke oven arrangement having the improved leveller bar for coke ovens,
substantially as herein described, particularly with reference to and as illustrated
in the accompanying drawings.

This invention relates to an improved leveller bar (202) for coke ovens for
levelling the coke bulk charging cone forming below the charging holes of a coke
oven chamber during the coal charging process thereby increasing coke oven
charge volume, the said improved leveller bar (202) is
characterized in that
a plurality of upstanding transversely extending cross plates (201), i.e., stiffners
(201) are inclined at a specified angle with a reduced height of the said stiffners
(201) having welded interconnected support elements extending over the entire
length of the oven chamber of a coke oven and are arranged in parallel to one
another at a distance dependent on the width of the oven chamber.
This invention also relates to a coke oven arrangement having the said improved
leveller bars (202), comprising:
a ram car; and
a coke oven defining a coke oven chamber with a charging hole forming a
charging cone below said charging hole, during a coal charging process.