Title of Invention	A SIMULATED ADHESION TESTING PROCESS TO EVALUATE ADHESION STRENGTH BETWEEN OLD AND NEW CLAY AT TAPHOLE OF BLAST FURNACE AND TESTING APPARATUS TO CARRY OUT THE METHOD
Abstract	This invention relates to a simulated adhesion testing process to evaluate adhesion strength between old and new clay at tap hole of blast furnace and a device to carry out the said method comprising the steps of forming a cylindrically shaped compact clay sample (1) by Marshal load test equipment, firing the said sample at required temperature, drilling a hole (2) of 25 - 50 mm dia. through the center of the clay sample (1), filling the drilled hole with same quality of new tap hole clay and firing the filled up sample at required temperature, evaluating adhesion strength of the filled up new sample (4) on applying load on the new sample through plunger (8).

Title of Invention

A SIMULATED ADHESION TESTING PROCESS TO EVALUATE ADHESION STRENGTH BETWEEN OLD AND NEW CLAY AT TAPHOLE OF BLAST FURNACE AND TESTING APPARATUS TO CARRY OUT THE METHOD

Abstract

This invention relates to a simulated adhesion testing process to evaluate adhesion strength between old and new clay at tap hole of blast furnace and a device to carry out the said method comprising the steps of forming a cylindrically shaped compact clay sample (1) by Marshal load test equipment, firing the said sample at required temperature, drilling a hole (2) of 25 - 50 mm dia. through the center of the clay sample (1), filling the drilled hole with same quality of new tap hole clay and firing the filled up sample at required temperature, evaluating adhesion strength of the filled up new sample (4) on applying load on the new sample through plunger (8).

Full Text	-2- FIELD OF THE INVENTION The present invention relates to simulated adhesion testing process between old and new clay mud at taphole of blast furnace and testing apparatus to carry out the method. More specifically the present invention relates to evolution of adhesion strength between old and new clay mud at taphole of blast furnace simulated to blast furnace conditions. -3- BACKGRQUND OF THE INVENTION WITH DIFFICULTIES OF PRIOR ART Taphole clay is used for purpose of plugging of taphole and discharge of iron and slag produced inside blast furnace. The mud gun inject or extrude the taphole clay into taphole of blast furnace where it hardens and block the hot metal and slag to come out from inside of blast furnace whereas drilling machine drill taphole clay in order to make hole or path for discharging iron and slag produced inside blast furnace. The performance of taphole clay is of fundamental importance to the successful running of a blast furnace. The taphole length, tapping duration and tapping rate are directly related to uniform furnace performance. The life of a blast furnace depends largely on the erosion of refractory lining of the hearth wall. One of the major operating factors that affect the erosion is metal flow in the hearth, especially, the extent of circumferential flow near the hearth wall region. The intensity of the circumferential flow is affected by the taphole length. A longer taphole reduces -4- the intensity of metal flow in the circumferential region, and reduces the wall lining erosion. A shorter taphole enhances the circumferential flow and increases the wall lining erosion. In consequence, the control of the taphole length is regarded as one of the indispensable measures to achieve longer blast furnace life. Basically taphole clay is expected to protect hearth side wall by creating protection layer of clay called mushroom around inside opening of taphole. Longer taphole length can be achieved only if the injected mud stays at around the in-furnace taphole opening and sinters there. To achieve the above condition it is necessary that the clay mud injected by mudgun should adhere well with the already existing clay mud. A test method has been innovated in order to measure the adhesion characteristics (strength) between old and new clay mud developed at high temperature. The present invention has proposed to enhance Blast Furnace life in a new approach of quantifying adhesion strength between old and new clay mud at taphole. -5- Earlier method for checking the adhesion quality of taphole clay involve silicon carbide crucible, after filling the crucible with taphole clay firing is to be done under reducing environment at 1450° C for 3 hrs. after cooling, the crucible is cut into two halves in order to see qualitatively weather taphole clay had stick with crucible wall or not. Above method of checking adhesion characteristics of taphole clay is inefficient in terms of differentiating different qualities of taphole clay adhesion characteristics which seems to be adhered (stick) with crucible side wall. With this method it is difficult to find out the value of adhesion strength between old and new taphole clay. Moreover this test method cannot be used to determine the adhesion characteristics between old and new clay mud. In order to differentiate adhesion characteristics of different type of taphole clay quantitative measurement of adhesion strength is necessary. -6- BRIEF DESCRIPTION OF THE INVENTION According to one object of the invention a test method of quantification of adhesion strength between old and new clay at taphole is proposed. Another objective of the invention is to predict the performance of taphole clay in terms of achieving long taphole length in actual blast furnace condition ascertaining adherence of new taphole clay mud pushed by mud gun into taphole with the already existing old taphole clay in front of inside opening of taphole. The major problem involved in earlier art is its inability to quantify the adhesion strength, also in earlier art result consist only qualitative observation of adhesion or sticking behaviors of taphole clay with silicon carbide crucible wall, but in the proposed invention the objective is to measure the adhesion characteristics (strength) between old and new clay mud developed at high temperature. -7- The testing procedure developed according to the invention is best understood from the following flow chart. Flow chart of the invented test method: -8- The invention will be better understood from the following description with reference to accompanying drawings in which Figure 1 shows a compact old clay sample by Marshal Load Test equipment. Figure 2 shows the drilled clay sample after firing at required temperature. Figure 3 shows schematically ejection of new clay from the old clay in CCS Machine to determine adhesion strength. Figure 4 shows Marshal Load Test Equipment. In the test method according to the invention a cylindrical shaped compact clay sample (1) is first prepared form Marshal Load test equipment (basically it is a simulation test of mud-gun taphofe clay pushing process) and is first Fired at around 1300 ~ 1500° C and soaked for some specified time (say 2-5 hr) under reducing environment. After firing, a hole (25~ 50 mm dia.) (2) is drilled -9- through the center of clay sample. After filling drilled hole with new taphole clay mud (4) the sample is again fired at around 1300 ~ 1500° C and soaked for some specified time (say 2-5 hr). In order to quantify the adhesion strength between newly filled taphole clay and cylindrical shaped already fired old taphole clay, a load is applied with the help of cold crushing strength (CCS) equipment only on new clay mud which had been filled in drilled hole. Adhesion strength (value) is the maximum load at which new clay mud starts to extrude out from old clay mud. Figure 3 shows the way load is applied only on new taphole clay mud with the help of CCS machine. In Figure 3, plunger (8) exerts pressure on the new clay (4) filled in the hole of compact old clay sample (1), numeral (6) showing the base of the CCS machine. Thus the new method not only solves the purpose of quantification of adhesion strength as well as involves clay-to-clay direct adhesion. -10- DETAILED DESCRIPTION OF THE INVENTION WITH ILLUSTRATION The main objective of new testing method is to simulate the actual blast furnace condition as much as possible. In actual blast furnace condition first, taphole clay mass is fed into the barrel of mudgun, where generally temperature lies around 60 -70° C and consequently it is pushed by piston of mudgun in dense compact form into blast furnace taphole. In Order to simulate above condition in lab, 1 kg of taphole clay sample is kept in the oven where temperature lies around 60° C for one hour. After taking out from oven the sample (1) is kept in the pre-1 ubricated mould of marshal load test equipment (Figure 4 shows Marshall load test equipment) then the plunger (3) of Marshal Load test Equipment is placed vertically above the clay sample (1) and pressure applied slowly with the help of hydraulically operated piston. At a certain pressure (depends on plasticity of taphole clay) clay sample starts to -11- extrude out from mould nozzle and forms compact cylindrical shaped sample. Dial gauge (7) of Marshal Load test equipment shows the pressure at which clay sample starts to extrude out from mould nozzle. Figure 1 shows the cylindrical shape clay sample (1) obtained from Marshal Load test equipment. This cylindrical shaped clay sample is then kept in atmospheric controlled furnace under reducing environment and fired at around 1300~ 1500° C and soaked for some specified time (say 2-5 hr.). After cooling this fired sample, a hole (2) (25~50 mm dia.) is drilled through the center of sample. Figure 2 shows drilled taphole clay sample. This drilled hole (2) is filled with the new taphole clay of same quality, preheated at 60° C to 70° C for one hour in the oven. The whole arrangement is kept inside atmospheric controlled furnace under reducing environment and fired at around 1300~1500° C and soaked for some specified time (say 2-5 hr). -12- After taking out the above sample from furnace the hole filled up sample is kept on cold crushing strength machine as shown in Figure 3. Then the load is applied with the help of CCS machine through plunger (8) only on clay sample filled in drilled hole. Maximum load at which new clay mud starts to extrude out from cylindrically shaped old clay mud gives adhesion strength of particular quality of taphole clay. The invention as narrated herein should not be read and construed in a restrictive manner as various modifications, alterations of dimensions of sample and test conditions and adaptations are possible within the scope and ambit of the invention as defined in the encompassed appended claims. -13- WE CLAIM 1. A simulated adhesion testing process to evaluate adhesion strength between old and new clay at tap hole of blast furnace comprising the steps of: - Keeping predetermined quantity of taphole clay sample in an oven at 60 -70° C for an hour simulated with actual blast furnace condition at taphole; - taking out the clay sample and keeping it in a pre-lubricated mould of marshal load test equipment in which equipment the plunger (3) is placed vertically above the clay sample and pressure applied slowly with the help of a hydraulically operated piston wherein at a certain pressure clay sample starts to extrude out from mould nozzle and forms compact cylindrical sample (1); -14- - keeping the compacted sample in atmospheric controlled furnace under reducing environment and fired at 1300-1500° with a soaking period of 2-5 hour; - on cooling of the sample a hole (25-50 mm dia.) is drilled through the centre of the sample; - filling the drilled hole (2) with new taphole clay of same quality of the sample, preheated to 60 - 70° C for an hour in the oven; - keeping filled up holed sample inside the atmospheric controlled furnace under reducing environment and fired at 1300 - 1500° C on soaking for 2-5 hour, the sample with old and filled up holed new clay is then put up in cold crushing strength machine wherein load is applied through plunger (8) only on the clay sample (4) filled in the drilled hole (2); -15- - recording maximum load at which new clay starts to extrude out from cylindrically shaped old clay to evaluate adhesion strength of particular quality of tap hole clay. 2. A testing device to carry out the testing process according to claim 1 in which the old compact clay sample is prepared by Marshal load test equipment simulated with test condition of mud-gun taphole clay pushing process, wherein the plunger (3) placed vertically above the clay sample material presses slowly with hydraulically operated piston to extrude out from the mould nozzle compact cylindrically shaped sample (1), the dial gauge (7) showing the pressure at which clay sample starts to extrude out from the mould nozzle; - drill arrangement provided to drill through the centre of fired sample (1) to drill hole (2), -16- - oven to fire sample (1) and also the filled up holed sample with new taphole clay (4) of same quality; - evaluating adhesion strength of the day sample filled in the drilled hole by the help of CCS machine, wherein the plunger (8) apply load on the said sample and evaluating the adhesion strength at the maximum load at which new clay (4) starts extruding out from the cyiindrically shaped old clay sample (1). This invention relates to a simulated adhesion testing process to evaluate adhesion strength between old and new clay at tap hole of blast furnace and a device to carry out the said method comprising the steps of forming a cylindrically shaped compact clay sample (1) by Marshal load test equipment, firing the said sample at required temperature, drilling a hole (2) of 25 - 50 mm dia. through the center of the clay sample (1), filling the drilled hole with same quality of new tap hole clay and firing the filled up sample at required temperature, evaluating adhesion strength of the filled up new sample (4) on applying load on the new sample through plunger (8).

Full Text

-2-
FIELD OF THE INVENTION
The present invention relates to simulated adhesion testing process between old
and new clay mud at taphole of blast furnace and testing apparatus to carry out
the method.
More specifically the present invention relates to evolution of adhesion strength
between old and new clay mud at taphole of blast furnace simulated to blast
furnace conditions.

-3-
BACKGRQUND OF THE INVENTION
WITH DIFFICULTIES OF PRIOR ART
Taphole clay is used for purpose of plugging of taphole and discharge of iron and
slag produced inside blast furnace. The mud gun inject or extrude the taphole
clay into taphole of blast furnace where it hardens and block the hot metal and
slag to come out from inside of blast furnace whereas drilling machine drill
taphole clay in order to make hole or path for discharging iron and slag produced
inside blast furnace. The performance of taphole clay is of fundamental
importance to the successful running of a blast furnace. The taphole length,
tapping duration and tapping rate are directly related to uniform furnace
performance. The life of a blast furnace depends largely on the erosion of
refractory lining of the hearth wall. One of the major operating factors that
affect the erosion is metal flow in the hearth, especially, the extent of
circumferential flow near the hearth wall region. The intensity of the
circumferential flow is affected by the taphole length. A longer taphole reduces

-4-
the intensity of metal flow in the circumferential region, and reduces the wall
lining erosion. A shorter taphole enhances the circumferential flow and increases
the wall lining erosion. In consequence, the control of the taphole length is
regarded as one of the indispensable measures to achieve longer blast furnace
life. Basically taphole clay is expected to protect hearth side wall by creating
protection layer of clay called mushroom around inside opening of taphole.
Longer taphole length can be achieved only if the injected mud stays at around
the in-furnace taphole opening and sinters there. To achieve the above
condition it is necessary that the clay mud injected by mudgun should adhere
well with the already existing clay mud. A test method has been innovated in
order to measure the adhesion characteristics (strength) between old and new
clay mud developed at high temperature. The present invention has proposed to
enhance Blast Furnace life in a new approach of quantifying adhesion strength
between old and new clay mud at taphole.

-5-
Earlier method for checking the adhesion quality of taphole clay involve silicon
carbide crucible, after filling the crucible with taphole clay firing is to be done
under reducing environment at 1450° C for 3 hrs. after cooling, the crucible is cut
into two halves in order to see qualitatively weather taphole clay had stick with
crucible wall or not. Above method of checking adhesion characteristics of
taphole clay is inefficient in terms of differentiating different qualities of taphole
clay adhesion characteristics which seems to be adhered (stick) with crucible side
wall. With this method it is difficult to find out the value of adhesion strength
between old and new taphole clay. Moreover this test method cannot be used to
determine the adhesion characteristics between old and new clay mud. In order
to differentiate adhesion characteristics of different type of taphole clay
quantitative measurement of adhesion strength is necessary.

-6-
BRIEF DESCRIPTION OF THE INVENTION
According to one object of the invention a test method of quantification of
adhesion strength between old and new clay at taphole is proposed.
Another objective of the invention is to predict the performance of taphole clay in
terms of achieving long taphole length in actual blast furnace condition
ascertaining adherence of new taphole clay mud pushed by mud gun into
taphole with the already existing old taphole clay in front of inside opening of
taphole.
The major problem involved in earlier art is its inability to quantify the adhesion
strength, also in earlier art result consist only qualitative observation of adhesion
or sticking behaviors of taphole clay with silicon carbide crucible wall, but in the
proposed invention the objective is to measure the adhesion characteristics
(strength) between old and new clay mud developed at high temperature.

-7-
The testing procedure developed according to the invention is best understood
from the following flow chart.
Flow chart of the invented test method:

-8-
The invention will be better understood from the following description with
reference to accompanying drawings in which
Figure 1 shows a compact old clay sample by Marshal Load Test equipment.
Figure 2 shows the drilled clay sample after firing at required temperature.
Figure 3 shows schematically ejection of new clay from the old clay
in CCS Machine to determine adhesion strength.
Figure 4 shows Marshal Load Test Equipment.
In the test method according to the invention a cylindrical shaped compact clay
sample (1) is first prepared form Marshal Load test equipment (basically it is a
simulation test of mud-gun taphofe clay pushing process) and is first Fired at
around 1300 ~ 1500° C and soaked for some specified time (say 2-5 hr) under
reducing environment. After firing, a hole (25~ 50 mm dia.) (2) is drilled

-9-
through the center of clay sample. After filling drilled hole with new taphole clay
mud (4) the sample is again fired at around 1300 ~ 1500° C and soaked for
some specified time (say 2-5 hr). In order to quantify the adhesion strength
between newly filled taphole clay and cylindrical shaped already fired old taphole
clay, a load is applied with the help of cold crushing strength (CCS) equipment
only on new clay mud which had been filled in drilled hole. Adhesion strength
(value) is the maximum load at which new clay mud starts to extrude out from
old clay mud. Figure 3 shows the way load is applied only on new taphole clay
mud with the help of CCS machine. In Figure 3, plunger (8) exerts pressure on
the new clay (4) filled in the hole of compact old clay sample (1), numeral (6)
showing the base of the CCS machine. Thus the new method not only solves the
purpose of quantification of adhesion strength as well as involves clay-to-clay
direct adhesion.

-10-
DETAILED DESCRIPTION OF THE
INVENTION WITH ILLUSTRATION
The main objective of new testing method is to simulate the actual blast furnace
condition as much as possible. In actual blast furnace condition first, taphole
clay mass is fed into the barrel of mudgun, where generally temperature lies
around 60 -70° C and consequently it is pushed by piston of mudgun in dense
compact form into blast furnace taphole.
In Order to simulate above condition in lab, 1 kg of taphole clay sample is kept in
the oven where temperature lies around 60° C for one hour. After taking out
from oven the sample (1) is kept in the pre-1 ubricated mould of marshal load test
equipment (Figure 4 shows Marshall load test equipment) then the plunger (3) of
Marshal Load test Equipment is placed vertically above the clay sample (1) and
pressure applied slowly with the help of hydraulically operated piston. At a
certain pressure (depends on plasticity of taphole clay) clay sample starts to

-11-
extrude out from mould nozzle and forms compact cylindrical shaped sample.
Dial gauge (7) of Marshal Load test equipment shows the pressure at which clay
sample starts to extrude out from mould nozzle. Figure 1 shows the cylindrical
shape clay sample (1) obtained from Marshal Load test equipment. This
cylindrical shaped clay sample is then kept in atmospheric controlled furnace
under reducing environment and fired at around 1300~ 1500° C and soaked for
some specified time (say 2-5 hr.). After cooling this fired sample, a hole (2)
(25~50 mm dia.) is drilled through the center of sample.
Figure 2 shows drilled taphole clay sample. This drilled hole (2) is filled with the
new taphole clay of same quality, preheated at 60° C to 70° C for one hour in the
oven. The whole arrangement is kept inside atmospheric controlled furnace
under reducing environment and fired at around 1300~1500° C and soaked for
some specified time (say 2-5 hr).

-12-
After taking out the above sample from furnace the hole filled up sample is kept
on cold crushing strength machine as shown in Figure 3. Then the load is
applied with the help of CCS machine through plunger (8) only on clay sample
filled in drilled hole. Maximum load at which new clay mud starts to extrude out
from cylindrically shaped old clay mud gives adhesion strength of particular
quality of taphole clay.
The invention as narrated herein should not be read and construed in a
restrictive manner as various modifications, alterations of dimensions of sample
and test conditions and adaptations are possible within the scope and ambit of
the invention as defined in the encompassed appended claims.

-13-
WE CLAIM
1. A simulated adhesion testing process to evaluate adhesion strength
between old and new clay at tap hole of blast furnace comprising the
steps of:
- Keeping predetermined quantity of taphole clay sample in an oven
at 60 -70° C for an hour simulated with actual blast furnace
condition at taphole;
- taking out the clay sample and keeping it in a pre-lubricated mould
of marshal load test equipment in which equipment the plunger (3)
is placed vertically above the clay sample and pressure applied
slowly with the help of a hydraulically operated piston wherein at a
certain pressure clay sample starts to extrude out from mould
nozzle and forms compact cylindrical sample (1);

-14-
- keeping the compacted sample in atmospheric controlled furnace
under reducing environment and fired at 1300-1500° with a
soaking period of 2-5 hour;
- on cooling of the sample a hole (25-50 mm dia.) is drilled through
the centre of the sample;
- filling the drilled hole (2) with new taphole clay of same quality of
the sample, preheated to 60 - 70° C for an hour in the oven;
- keeping filled up holed sample inside the atmospheric controlled
furnace under reducing environment and fired at 1300 - 1500° C
on soaking for 2-5 hour, the sample with old and filled up holed
new clay is then put up in cold crushing strength machine wherein
load is applied through plunger (8) only on the clay sample (4)
filled in the drilled hole (2);

-15-
- recording maximum load at which new clay starts to extrude out
from cylindrically shaped old clay to evaluate adhesion strength of
particular quality of tap hole clay.
2. A testing device to carry out the testing process according to claim 1 in
which the old compact clay sample is prepared by Marshal load test
equipment simulated with test condition of mud-gun taphole clay pushing
process, wherein the plunger (3) placed vertically above the clay sample
material presses slowly with hydraulically operated piston to extrude out
from the mould nozzle compact cylindrically shaped sample (1), the dial
gauge (7) showing the pressure at which clay sample starts to extrude
out from the mould nozzle;
- drill arrangement provided to drill through the centre of fired
sample (1) to drill hole (2),

-16-
- oven to fire sample (1) and also the filled up holed sample with
new taphole clay (4) of same quality;
- evaluating adhesion strength of the day sample filled in the drilled
hole by the help of CCS machine, wherein the plunger (8) apply
load on the said sample and evaluating the adhesion strength at
the maximum load at which new clay (4) starts extruding out from
the cyiindrically shaped old clay sample (1).

This invention relates to a simulated adhesion testing process to evaluate adhesion
strength between old and new clay at tap hole of blast furnace and a device to carry out
the said method comprising the steps of forming a cylindrically shaped compact clay
sample (1) by Marshal load test equipment, firing the said sample at required
temperature, drilling a hole (2) of 25 - 50 mm dia. through the center of the clay
sample (1), filling the drilled hole with same quality of new tap hole clay and firing the
filled up sample at required temperature, evaluating adhesion strength of the filled up
new sample (4) on applying load on the new sample through plunger (8).

Documents:

00975-kol-2007-abstract.pdf

00975-kol-2007-claims.pdf

00975-kol-2007-correspondence others 1.1.pdf

00975-kol-2007-correspondence others.pdf

00975-kol-2007-description complete.pdf

00975-kol-2007-drawings.pdf

00975-kol-2007-form 1.pdf

00975-kol-2007-form 18.pdf

00975-kol-2007-form 2.pdf

00975-kol-2007-form 3.pdf

00975-kol-2007-gpa.pdf

975-KOL-2007-(01-11-2011)-ABSTRACT.pdf

975-KOL-2007-(01-11-2011)-AMANDE CLAIMS.pdf

975-KOL-2007-(01-11-2011)-DESCRIPTION (COMPLETE).pdf

975-KOL-2007-(01-11-2011)-DRAWINGS.pdf

975-KOL-2007-(01-11-2011)-EXAMINATION REPORT REPLY RECIEVEDPDF

975-KOL-2007-(01-11-2011)-FORM 1.pdf

975-KOL-2007-(01-11-2011)-FORM 2.pdf

975-KOL-2007-(01-11-2011)-FORM 3.pdf

975-KOL-2007-(01-11-2011)-FORM 5.pdf

975-KOL-2007-(01-11-2011)-OTHERS.pdf

975-KOL-2007-(01-11-2011)-PETITION UNDER RULE 137.pdf

975-KOL-2007-CORRESPONDENCE.pdf

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Patent Number

252098

Indian Patent Application Number

975/KOL/2007

PG Journal Number

17/2012

Publication Date

27-Apr-2012

Grant Date

25-Apr-2012

Date of Filing

09-Jul-2007

Name of Patentee

TATA STEEL LIMITED.

Applicant Address

JAMSHEDPUR

Inventors:

#	Inventor's Name	Inventor's Address
1	AMAN	TATA STEEL LIMITED. JAMSHEDPUR-831 001
2	RANJAN PAL, ATANU	TATA STEEL LIMITED. JAMSHEDPUR-831 001

PCT International Classification Number

G01N 3/48

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA