Metal working – Method of mechanical manufacture – Repairing
Reexamination Certificate
1999-12-21
2003-04-01
Vidovich, Gregory M. (Department: 3726)
Metal working
Method of mechanical manufacture
Repairing
C029S402030, C029S402080, C029S402090, C029S426100, C029S464000, C052S514000, C052S218000
Reexamination Certificate
active
06539602
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of repairing a chamber type coke oven. Specifically, the present invention relates to a method of repairing damaged walls of combustion chambers near oven openings of a coke oven with high efficiency. It further relates to a method of relaying bricks to build up coke oven walls, to a method of heat-insulating a part of a coke oven during repair of a brick wall therein, and to an apparatus for taking bricks into a coke oven for repair. More particularly, the present invention relates to a coke oven repairing method which is applicable even to a coke oven having combustion chambers with a complicated brick structure, such as a Carl Still coke oven.
2. Description of the Related Art
Generally, as shown in
FIG. 1
, a coke oven includes a regenerator
9
in its lower portion, and a plurality of coking chambers
2
and combustion chambers
4
arranged alternately side by side in its upper portion, thereby constituting an oven battery. Coal is charged into the coking chambers
2
from a charging car
51
traveling over the coke oven, and is carbonized under heat applied from the combustion chambers
4
on both sides. After opening a door
8
of each coking chamber
2
, the carbonized coal, i.e., coke, is pushed out from the coking chamber
2
into a quenching car
53
via a guide car
54
by a pushing machine
52
, followed by being transported to a red coke quenching facility (not shown) in the quenching car
53
.
The regenerator
9
and the combustion chambers
4
are constructed using bricks. Inside the regenerator
9
and the combustion chambers
4
, there are formed passages through which flow the fuel gas, air and combustion exhaust gas generated when the fuel gas mixes with air and burning. In particular, the combustion chambers
4
are each structured by laying bricks in a combined manner to form those passages. Outer wall surfaces of the combustion chamber
4
serve also as brick wall surfaces of the adjacent coking chambers
2
. Thus, each coking chamber
2
is a space surrounded by the outer wall surfaces of the two adjacent combustion chambers
4
, the door
8
at the side near the pushing machine
52
, and a door
10
at the side near the guide car
54
.
For carbonizing coal in the coking chambers
2
into homogeneous coke, the temperature in the coking chambers
2
needs to be kept as uniform as possible. To that end, various types of structures have been proposed relating to the passages for the fuel gas, air and the combustion exhaust gas which is formed in the regenerators
9
and the combustion chambers
4
.
FIG. 2
is a perspective sectional view of Carl Still type coke ovens, as an example having two-divided combustion chambers and having horizontal flues at the top of each row of combustion chambers. In a two-divided type coke oven, the combustion chamber
4
and the regenerator
9
are each divided into two sides: the pushing-machine located side (machine side: hereinafter abbreviated to M/S)
17
and the guide-car located side (coke side: hereinafter abbreviated to C/S)
16
, both of the sides being coupled via a horizontal flue
14
at the top of the combustion chamber
4
. The direction in which the M/S and C/S are interconnected is referred to as the longitudinal direction of the oven; it is indicated by arrow
18
in FIG.
2
. The direction along which the combustion chambers and the coking chamber are alternately arranged side by side is referred to as the transverse direction of the oven; it is indicated by arrow
19
in FIG.
2
.
Still referring to
FIG. 2
, fuel gas
61
and air
62
for combustion are both supplied from below the regenerator
9
of the C/S flow through the passages in the regenerator
9
for preheating, and then flow upwardly through the combustion chamber
4
. Within the combustion chamber
4
, the fuel gas passages and the air passages have openings formed in multiple stages for communication with vertical flues
11
. The openings in the fuel gas passages are referred to as gas ports, and the openings in the air passages are referred to as air ports. The fuel gas
61
and the air
62
are mixed with each other in the vertical flues
11
, whereupon the fuel gas burns. The fuel gas passages and the air passages in the combustion chamber are each called a multistage burner duct
12
. Flows of the combustion exhaust gas generated in the vertical flues
11
join together in the horizontal flue
14
, advance in the longitudinal direction of the oven, and reach the M/S of the combustion chamber. Then, the combustion exhaust gas flows downward from the upper horizontal flue
14
into vertical flues
11
of the M/S, goes into multistage burner ducts
12
through gas ports and air ports in a reversed direction as compared to that in the C/S, and passes the regenerator
9
, followed by being exhausted from a smokestack
20
. After continuing the above combustion process for 20 to 30 minutes, the fuel gas
61
and the air
62
are supplied from the M/S oppositely. The combustion exhaust gas flows from the M/S to the C/S, and is then exhausted. As a result of repeating the above two combustion process alternately, the temperatures in both the C/S and M/S of the combustion chamber are kept uniform.
In this way, the coke oven of
FIG. 2
is operated so that the temperature is kept as uniform as possible throughout the oven. At the time of discharging the produced coke to the outside of the oven, however, the doors at both ends are opened and the coke is pushed out by the pushing machine as described above. Therefore, open air flows into the oven, and the oven walls near the doors are subjected to abrupt rising and falling of temperature. It is also inevitable that the wall surfaces of the coking chambers are abraded by the coke being pushed out. Accordingly, the use of the coke oven for a long period of time often gives rise to significant damage of the oven walls, particularly near the doors. In the case of serious damage, the oven is repaired by hot-relaying of bricks to form the oven walls.
Heretofore, the wall of a coking chamber has been repaired as follows.
First, two adjacent coking chambers are emptied. Then, combustion is ceased in one combustion chamber formed in an oven wall to be repaired and in two combustion chambers adjacent to the former. Simultaneously, a heat-insulating material is installed so as to surround an area covering from the boundary between a rebuilt (repaired) portion and a not-repaired portion of the one combustion chamber to the oven openings between the two combustion chambers. The reason for surrounding the rebuilt portion with the heat-insulating material is to prevent temperature drop of bricks in the not-repaired portion of the one combustion chamber and bricks in the two adjacent combustion chambers. Another reason is to accelerate cooling of bricks in the rebuilt portion at the same time. The temperature in the working space is thus lowered to such a level as to allow the start of brick relaying work.
After supporting ceiling bricks of the rebuilt portion by hanging hardware to prevent those bricks from dropping, the brick wall in the rebuilt portion is dismantled and oven fastening hardware is removed. The all serving as a partition between the two adjacent coking chambers is partly dismantled. Subsequently, in the positions left open after dismantling, new bricks are manually laid one by one to restore the wall, and the oven fastening hardware is installed.
In laying bricks one by one, the thickness of joints between bricks laid in the repaired portion and the positions of bricks fitted to each other are adjusted. For adjustment, the dimensions of the space left open after dismantling the brick wall to be rebuilt are measured, and the dimensions of a rebuilt brick wall in a condition after the oven temperature has been completely raised are calculated, taking into account the three-dimensional position of the not-repaired portion of the brick wall of the combustion chamber, and the thermal expansion of the brick
Kamide Nobuya
Osaki Yuzuru
Ozawa Tatsuya
Sato Yoshiharu
Tamura Nozomu
Jimenez Marc
Kawasaki Steel Corporation
Schnader Harrison Segal & Lewis LLP
Vidovich Gregory M.
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