FIELD OF INVENTION
The present invention generally relates to determination of physical strength of
iron oxides and coke used in Blast furnace for Hot metal production. More
particularly, the invention relates to an improved apparatus and process for
measurement of and hot strength of iron oxides like Iron ore, Sinter and Pellet.
The invention further relates to a method of manufacturing an apparatus for
measurement of coke strength after reaction and/or hot strength of iron oxide
bearing materials.
BACKGROUND OF INVENTION
Coke strength is an indicator of physical strength of a coke. Coke strength
represents the resistance of coke to breakage after it has been reacted in CO2
atmosphere at a temperature around 1100°C in a reaction vessel. A test to
determine the coke strength is necessary because when coke lumps descend in
the Blast Furnace, they are allowed to react with a stream of concurrent
ascending CO2 gas. As the coke undergoes intra-friction and rubbing against the
wall of the furnace, they get abrased. This test is done in accordance with IS
4023:1991, reaffirmed in 1996. Similarly, RDI/RI test of Iron Ore/Sinter/Pellet
are conducted when the temperature in the reaction vessel is raised to 550/900
degree centigrade and CO+N2 passed through a sample @ 15 liter/min in the
ratio of 30:70 for 30/180 min respectively. These prior art tests were designed to
predict indirectly the behavior of Iron Ore/Sinter/Pellet in the Blast furnace. RDI
test is done in accordance with IS-10823:1994, reaffirmed in 2001. RI test is
carried out as per IS 8167:1989, reaffirmed in 2005.

According to prior art, Lump Coke samples are crushed into a size range of
(-21mm to + 19mm) with the help of a Jaw Crusher, and dried to achieve a
moisture content of less than 3%. Similarly in case of Iron Ore/Sinter/Pellet-
15+10 mm size sample is taken. A plurality of A12O3 balls are placed on a
perforated plate disposed inside the Reaction Vessel, and then the sample is put
over the balls. As per ASTM/ISO standard a thermo well with thermo couple is
placed in the centre of the sample as depicted in figures 1 to 6.
In the Reaction Vessels as per IS-4023/1991, IS-8167/1989 and IS-10823/1994,
the temperature-measuring device (thermocouple) have to place in the centre of
the sample mass. Most of the reaction vessel manufacturer had developed the
apparatus (Reaction Vessel) in such a way that thermo well, in which
thermocouple inserts, constitutes an integral part of the top cover, which is used
to close the reaction vessel from the top.
In the existing vessels, it is very difficult to insert the thermo well substantially in
the centre of the sample mass. Once the sample is placed in the reaction vessel,
the thermo well resides either outside of the sample or damages the sample
which leads to inaccurate test result.
OBJECTS OF INVENTION
It is therefore an object of the invention to propose an improved apparatus
(Reaction Vessel) for measurement of coke strength after reaction and/or hot
strength of iron oxide bearing materials, which eliminates the disadvantage of
prior art and confirms the applicability of the standards.

Another object of the invention is to propose an improved apparatus (Reaction
Vessel) for measurement of coke strength after reaction and/or hot strength of
iron oxide bearing materials, which provides instead of an integral thermo well
an independent thermo well that constitutes a disintegrable part of the top cover
flange.
A still another object of the invention is to propose an improved apparatus
(Reaction Vessel) for measurement of coke strength after reaction and/or hot
strength of iron bearing materials, which in particular eliminates the
disadvantage of thermo well insertion into the sample.
Yet another object of the invention is to propose an improved apparatus
(Reaction Vessel) for measurement of coke strength after reaction and/or hot
strength of iron bearing materials, which more particularly avoids the sample
disintegration on insertion of the thermo well, which generally lead to inaccurate
measurement.
A further object of the invention is to propose a method of manufacturing an
apparatus (Reaction Vessel) for measurement of coke strength after reaction
and/or hot strength of iron bearing materials.
SUMMARY OF INVENTION
In the prior art vessels, the problem is faced in insertion of the thermo well at
the centre of the sample. According to the invention, a hollow pipe is fist inserted
over A12O3 balls to create a cavity and then the sample has put around the
hollow pipe. After putting the sample between the hollow pipe and reaction
vessel wall, the pipe has taken out and then the thermo well has slowly inserted

so that the sample does not fall in the cavity made earlier. If any piece of the
sample falls in the cavity then the same restricts the insertion step of the thermo
well in the cavity. In such a case, the process is to repeat once again. During the
insertion, the cavity remains beneath the flange of the Top cover. Therefore,
nothing is visible from the top and one has to insert the thermo well in the cavity
with a high level of skill.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 - Shows a pictorial view of a thermocouple integrated with top
cover flange of the apparatus of prior art.
Figure 2 - Shows a pictorial view of a first step of preparation for
implementing the process of measurement of coke reactivity
strength including hot strength of iron bearing materials
according to prior art.
Figure 3 - Shows a pictorial view of a second step of preparation for
implementing the process of measurement of coke reactivity
strength including hot strength of iron bearing materials
according to prior art.
Figure 4 - Shows a pictorial view of a third step of preparation for
implementing the process of measurement of coke reactivity
strength including hot strength of iron bearing materials
according to prior art.

Figure 5 - Shows a pictorial view of a visible cavity formed for inserting
the thermo well in an apparatus of prior art.
Figure 6 - Shows a schematic diagram of a prior art apparatus for
measurement of coke reactivity strength including hot strength
of iron bearing materials according to prior art.
Figure 7 - Shows a flow chart depicting the steps of the process for
measurement of coke strength including hot strength of
iron bearing materials according to the invention.
Figure 8 - Shows a pictorial view of an improved apparatus according
to the invention.
Figure 9 - Shows a pictorial view of an improved apparatus of the invention
in empty condition.
Figure 10 - Shows a pictorial view of an improved apparatus of the
invention, with thermo well.
Figure 11 - Shows a pictorial view of an improved apparatus of the invention,
with alumina ball inserted.
Figure 12 - Shows a pictorial view of an improved apparatus of the invention,
with sample of coke or iron bearing materials inserted.
Figure 13 - Shows a pictorial view of an improved apparatus of the invention,
with top cover flange placed on the reaction vessel.

Figure 14 - Shows a schematic view of the improved apparatus according to
the invention.
DETAIL DESCRIPTION OF THE INVENTION
Figure 6 shows a schematic view of the prior art apparatus (Reaction Vessel) for
measurement of coke reactivity strength including hot strength of iron oxide
bearing materials.
As shown in figure 6, a reaction vessel (6) is placed inside an electric furnace (3).
Two different gases (N2 & CO2) is supplied through gas flow meters (2) into the
reaction vessel (6). A test sample (3) is prepared by crushing coke lumps or iron
bearing material into a specified size range. A perforated plate (9) is disposed at
the bottom of the vessel (6), and a plurality of A12O3 balls (5) placed on the
perforated plate (9). The test sample (3) is placed over the A12O3 balls (5). A
thermo well with thermo couple (1) is placed in the centre of the test sample (3).
As shown in figure 14, the thermocouple (1) is cut and separated from the top
cover flange (7), and does not form an integral part. A tripod (6a) is made of at
least three small length of inconnel tube, and welded with a dummy flange. An
oversize inconnel tube (8) (+lmm than the outer diameter of the small length
inconnel tube) is attached to the bottom of the top cover flange (7) keeping the
centre line identical with that of the thermocouple (1).
As illustrated in figure 7, the process for measurement of coke reactivity strength
and/or hot strength of iron bearing materials comprises:

At step 100, a perforated plate (9) is placed inside the reaction vessel (6). A first
plurality of alumina balls (5) is placed (101) on the perforated plate (9). A hollow
pipe (8) is inserted (102) in the center of the reaction vessel (6) such that the
pipe (8) touches the first plurality of alumina balls (5). Placing (103) a second
plurality of alumina balls (5) in the reaction vessel (6). Inserting (104) the test
sample (4) in the reaction vessel (6). The inserted hollow pipe (8) is then taken
out (106) from the sample (4) to create a cavity. Inserting (107) the thermo well
with lid (7) in the cavity. The lid (7) is then fastened (108) over the vessel (6).
The thermocouple (1) is inserted (109) into the thermo well. The reaction vessel
is thereafter charged (110) into the electric furnace (3).
EXPERIMENTAL RESULT
An experiment has been carried out to establish the results of the invention. In
this experiment an Inconnel-600 tube, which has been an integral part of the
Top cover flange of the reaction vessel has been cut. A new Inconnel-600 tube
of 600 mm in length has been attached with three numbers of small pieces of
Inconnel-600 tube and made a tripod and welded with a dummy flange. By this
way, it is possible to locate the well in the centre of the Reaction vessel. A
slightly over size (+lmm than the outer diameter) Inconnel-600 tube is fixed in
the bottom of the Top Cover flange keeping the centre line identical.
This new Reaction Vessel has been tried for several times for putting the sample
in to the reaction vessel and it was observed that the thermo well remains in the
centre of the sample. The height of the bed can be varying as per requirement of
the test by increasing or decreasing the number of A12O3 balls.

WE CLAIM :
1. A method of manufacturing an apparatus (Reaction Vessel) for
measurement of coke strength after reaction and/ or hot strength of iron
bearing materials, the method comprising the steps of:
(i) providing a reaction vessel for carrying out the test for measurement;
(ii) separating the thermocouple in-built with the top flange cover flange
of the vessel;
(iii) configuring a tripod by cutting and welding at least three pieces of
inconnel tube and rigidly attaching the tripod with a dummy flange;
(iv) providing a single piece inconnel tube having diameter at least + 1mm
over that of the inconnel pieces forming the tripod, the oversized
inconnel tube having a length higher than each of said three inconnel
pieces forming the tripod;
(v) attaching the oversized and longer single piece inconnel tube at the
bottom of the top flange cover from where the thermocouple was
separated which constitutes a thermo well with lid;
(vi) providing a perforated plate at a bottom portion of the reaction vessel;

(vii) Placing a first plurality of alumina balls on the perforated plate
including the test sample and a second plurality of alumina balls, and
inserting a hollow pipe through the centre of the reaction vessel such
that the bottom of the hollow pipe touches the first plurality of alumina
balls;
(viii) withdrawing the hollow pipe from the vessel so as to leave behind a
cavity formed on the test sample;
(ix) inserting the thermo well with lead and fastening the lead over the
reaction vessel; and
(x) inserting the thermocouple formed in step (iii) into the thermo well;
(xi) placing the reaction vessel with the apparatus into an electric furnace
for testing and measurement of coke reactivity strength and/or hot
strength of iron bearing materials.
2. An improved apparatus for measurement of coke reactivity strength
and/or hot strength of iron bearing materials, the improvement is
characterized in that :-
the top lid cover of the reaction vessel is stripped of to isolate the
thermo well;
the stripped thermo well is attached to a dummy lid;

the top lid cover is provided with a hollow pipe with diameter and
length higher than those of the detached thermocouple which acts as a
lid with thermo well; and
On insertion of the lid with thermo well inside the reaction vessel having
test sample, and the thermocouple can be inserted in that thermo well
without disturbing the test sample.
3. A method of manufacturing an apparatus for measurement of coke
reactivity strength and/or hot strength of iron bearing materials as
substantially described and illustrated herein with reference to the
accompanying drawings.


fastening the lid over the reaction vessel; and inserting the thermocouple formed
in step (iii) into the thermo well; placing the reaction vessel with the apparatus
into an electric furnace for testing and measurement of coke reactivity strength
and/or hot strength of iron bearing materials.
{FIGURE 7}

The invention relates to a method of manufacturing an apparatus for
measurement of coke strength after reaction and/or hot strength of iron oxide
bearing materials. The method comprising the steps of providing a reaction
vessel for carrying out the test for measurement; separating the thermocouple
in-built with the top flange cover flange of the vessel; configuring a tripod by
cutting and welding at least three pieces of inconnel tube and rigidly attaching
the tripod with a dummy flange, providing a single piece inconnel tube having
diameter at least + 1mm over that of the inconnel pieces forming the tripod. The
oversized inconnel tube having a length higher than each of said three inconnel
pieces forming the tripod; attaching the oversized and longer single piece
inconnel tube at the bottom of the top flange cover from where the
thermocouple was separated which constitutes a thermo well with lid; providing
a perforated plate at a bottom portion of the reaction vessel; placing a first
plurality of alumina balls on the perforated plate and inserting a hollow pipe
through the centre of the reaction vessel such that the bottom of the hollow pipe
touches the first plurality of alumina balls and then second plurality of alumina
balls. Then putting the sample between the hollow pipe and the wall of the
reaction vessel. Withdrawal of the hollow pipe from the vessel, which leaves
behind a cavity formed on the test sample; inserting the thermo well with lid and
fastening the lid over the reaction vessel; and inserting the thermocouple formed
in step (iii) into the thermo well; placing the reaction vessel with the apparatus
into an electric furnace for testing and measurement of coke reactivity strength
and/or hot strength of iron bearing materials.