CA2195541A1 - Nozzle for blowing gas into molten metal and usage thereof - Google Patents
Nozzle for blowing gas into molten metal and usage thereofInfo
- Publication number
- CA2195541A1 CA2195541A1 CA002195541A CA2195541A CA2195541A1 CA 2195541 A1 CA2195541 A1 CA 2195541A1 CA 002195541 A CA002195541 A CA 002195541A CA 2195541 A CA2195541 A CA 2195541A CA 2195541 A1 CA2195541 A1 CA 2195541A1
- Authority
- CA
- Canada
- Prior art keywords
- gas
- blast nozzle
- refractory
- gas blast
- nozzle
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/42—Constructional features of converters
- C21C5/46—Details or accessories
- C21C5/48—Bottoms or tuyéres of converters
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D1/00—Treatment of fused masses in the ladle or the supply runners before casting
- B22D1/002—Treatment with gases
- B22D1/005—Injection assemblies therefor
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/072—Treatment with gases
Abstract
A nozzle for blowing a gas into a molten metal in a stable manner without causing the leakage of gas from its periphery, which has a simple structure and a long life, so that it does not require frequent replacements. The gas blowing nozzle comprises a refractory block formed unitarily with a metallic mounting member and provided with a small diameter through hole therein, and a small-diameter metallic gas blowing tube inserted slidably through the small-diameter hole. When the gas blowing nozzle and the surrounding refractory are worn, the metallic gas blowing tube is extended into the interior of a furnace, and a worn portion is repaired by packing a repairing material therein.
Description
~ 21 qS~41 SPECIFICATION (e~) GAS BLAST NOZZLE FOR MOLTEN METAL
AND
METHOD OF USING THE SAME
[Technical Field]
This invention relates to a gas blast nozzle for molten metal in a smelting furnace such as an electric furnace or another refining furnace.
More particularly, it relates to a gas blast nozzle for molten metal that can be repaired easily and a method of using the same.
[Background Art]
FIG. ~ of the accompanying drawings illustrates examples of known gas blast nozzle. In FIG. 5, (a), (b) and (c) ~ ,e~;tiv~ly show a single pipe nozzle, a double pipe nozzle and a multi-pipe nozzle, and (d) shows a porous plug. In FIG. ~, reference numerals (10) and (11) L~e.liv~ly denote a gas feed hose and a l~L~IotuL,~ in furnace bottom, whereas (17) and (18) respectively denote a cooling gas feed pipe and a porous brick. A multi-pipe nozzle of (c) in FIG. 5 may be realized by burying a plurality of small metal pipes in a l~L~ y block and such multi-pipe nozzle has been popularly used for electric furnaces because fine and evenly sized gas bubbles can be produced in molten metal by means of the multi-pipe nozzle.
As gas is blown into molten metal through a gas blast nozzle in a refining furnace, the inner side of refractory of the furnace becomes remarkably worn away in an area ~ul~Ju..dillg the gas blast nozzle as shown (8) in FIG. 2(a) as the molten metal in the furnace is fiercely moved by the gas in an area near the gas blast nozzle. When the lost portion (8) has grown too big, the gas blast nozzle has to be replaced, which results in 21 9~
' - 2 -sl~p~n-ling of the operation of the furnace. Furthermore, such a nozzle replacing operation has to be conducted in an adverse environment and, therefore, it i8 not reromml~nl1~d to replace the gas blast nozzle frequently.
Japanese Pàtent Application Laid-Open Publication No. 58-81937 discloses "a gas blast plug comprising a refractory nozzle block having bore therethrough and a small metal pipe placed in the bore with an annular gap to an inner surface of the bore.
FIG. 6 of the accompanying drawings illustrates the gas blast plug according to the above. Referring to FIG. 6(a), an annular gap is formed between the inner surface of the bore and outer surface of the small metal pipe (2), such that a thickness of the annular gap is as thin as not leak molten metal. In FIG. 6(a), a gas feed hose (not shown) is connected to the small metal pipe (2). The arr~ngl~m~nt shown in FIG. 6 seemed to be effective for prolong a service life of gas blast nozzle, since the gas blast nozzle can be repaired when it is partly lost during its usage, and can be served for long term without replacing it.
However, the inventors of the present invention have found that, when the gas blast plug according to the above is used in electric refining furnace, the gas tends to move into the annular gap rather than entering into the molten metal as shown in FIG. 6(b). When a supply of the gas from the small metal pipe (2) is at a low rate and the gas is blown in from the bottom of the furnace, a big statistic pressure of the molten metal at the bottom of the furnace may resist the gas entering into the molten metal, and the gas move more easily into the annular gap than into the molten metal.
However, the above invention does not provide a solution to this problem.
[DISCLOSURE OF THE INVENTION]
The present invention provides a gas blast nozzle that .,.i..;. .i~.s the '' -3-down time of a furnace for replacing the gas blast nozzle because it seldom requires the repl~rPmrnt, reduces the work load of the replacing operation under adverse working conditions and is free from the problem of gas leaking through the gas blast nozzle.
FIG. I ofthe ~rr~mp~nying drawings shows a gas blast nozzle according to the invention. In FIG. l, (a) is a longitudinal sectional view of the gas blast nozzle by itself and (b) is also a longitudinal sectional view of the gas blast nozzle showing how it is arranged in the bottom of a furnace, whereas (c) is also a longitudinal sectional view illustrating with a coupler for connf~rting it with a gas feed hose.
According to the invention, there is provided a gas blast nozzle for molten metal comprising a refractory block (4~ having a narrow straight bore (3) being bored from the inside to the outside of a furnace, a tubular metal fitting (22) formed in one body with the refractory block (4), a small metal pipe (2) arranged slidably through the straight bore (3) of said refractory block (4) and a metal coupler (23) for ronn~rting a gas hose (15) to an end of said tubular metal fitting (22), cLa~ d in that an outer end portion of said small metal pipe (2) is made to penetrate through a rubber block (14) in said metal coupler (23) and the gas (12) fed to the metal coupler (23) is blown into the molten metal in the furnace from the inner end of said small metal pipe (2).
The tubular metal fitting (22) is tubular at an end and has a saucer-like profile at the other end to snugly receive the bottom of the refraciory block (4) so that the refractory block (4) is f tted and bonded to the tubular metal fitting (22) at its bottom to make them in one body with each other.
Since the refractory block (4) and the tubular metal fitting (22) are made in one body with each other as well as the small metal pipe is made to ~ 1 ~5~ ~
'~ -4-penetrate through the rubber block, gas is securely prevented from leaking through the annular gap between the small metal pipe (2) and the refractory block (4) unlike the case of FIG. 6(b).
As seen from FIG. l(c), the tubular end of the metal fitting (22) is ~onne-~ted to an end of the metal coupler (23), and the other end of the metal coupler (23) is connected to a gas hose (15).
The outer end of the small metal pipe (2) is made to penetrate the rubber block (14) and open for the gas hose (15). The gap between the outer periphery of the small metal pipe (2) and the inner surface of the metal coupler (23) is sealed by the rubber block (14) so that all the gas (12) fed in from the gas hose (15) is blown into the small metal pipe (2).
While FIG. 1 shows a gas blast nozzle (1) having a single small metal pipe (2), a gas blast nozzle according to the invention may alternatively .
comprise a plurality of small metal pipes (2) in such a way that the gap between each of the small metal pipes (2) and the colle~ line metal coupler (23) is filled with a rubber block (14) so that all the gas fed in may be blown into the small metal pipes (2) regardless of the number of small metal pipes (2).
As shown in FIG. l(b), the gas blast nozzle (1) is fitted to the tuyere-forming brick (6) at the L~r ~ Wy bottom (11) of the furnace and secured to the outer shell (19) of the furnace by means of a securing ring (21) and a lock member (20). At the time, the gap between the nozzle and the tuyere-forming bricks is filled with some castable refractory substance (5).
The small metal pipe (2) may be a stainless steel pipe having an inner diameter of 1 to 2 mm, although the inner diameter and the number of pipes may be selected depending on the gas flow rate. Additionally, the small metal pipe may be a single pipe or a double pipe. Note that the inner 2 ~
diameter of the straight bore (3) is made greater than the outer diameter of the small metal pipe (2) by 0 to 4 mm in order to allow the small metal pipe (2) smoothly to move vertically.
FIG. 2 illustrates a method of using the gas blast nozzle (1) according to the invention. A gas blast nozzle (1) according to the invention is worn and wears away the inner refractory during its usage to produce a lost portion (8) as shown in FIG. 2(a). According to the invention, the lost portion (8) is repaired by moving upward the small metal pipe (2) in the straight bore (3) until the inner end of the small metal pipe (2) projects over the inside of the furnace as shown in FIG. 2(b).
Then, the lost portion (8) is filled with a refractory material (16) without closing the inner end of the small metal pipe (2) as shown in FIG.
2(c). In FIG. 2(c), the inner end of the small metal pipe (2) is projecting overthe inner surface of the furnace after the lost portion is filled with the refractory material (16). And the inner end of the small metal pipe (2) would not be buried nor clogged by this projection even if in an usual repairing apparatus of the furnace lining such as a sand slinger is used to fillthe lost portion (8) with an ordinary refractory material for repairing of the lining of the furnace.
Thus, with a gas blafft nozzle (1) according to the invention, the gas blast nozzle and its peripheral area can be repaired easily, if necessary, in the routine operation for ml3int~ining the furnace bottom and the furnace wall, which consequently prolong the service life of the gas blast nozzle 80 that the frequency of replacing the gas blast nozzle will be remarkably reduced.
When gas is blown into the molten metal in the furnace after filling the lost portion as shown in FIG. 2(c), the projecting portion of the small 2 ~ 9 ~
metal pipe (2) i8 immediately molten away and the inner end of the gas blast nozzle will show a profile as shown in FIG. l(b). And, the gas blast nozzle operates to blow gas into the molten metal as stably as before.
FIG. 3 illustrates another embodiment of gas blast nozzle according to the invention. In FIG. 3, (a) is a longitudinal sectional view of the gas blast nozzle and (b) is also a longitudinal sectional view showing how the gas blast nozzle is arranged in the bottom of a furnace.
The gas blast nozzle of FIG. 3(a) differs from that of FIG. l(a) in that the refractory block (4) is divided into upper and lower pieces. Otherwise, it is the same as its counterpart of FIG. l(a). As described earlier in FIG. l(c), the tubular metal fitting (22) is coupled at its outer end to a gas hose (15) bymeans of a metal coupler (23) and the annular gap around the small metal pipe (2) is sealed by a rubber block (14).
As shown in Fig. 3(b), the gas blast nozzle is also fitted to the tuyere-forming bricks (6) at the refractory bottom (11) of the furnace and secured to the outer shell (19) of the furnace by means of a securing ring (21) and a lock member (20). Also, the gap between the nozzle and the tuyere-forming bricks is filled with some castable refractory substance.
FIG. 4 illustrates a method of using the gas blast nozzle illustrated in FIG. 3. The lost portion (8) in FIG. 4(a) is repaired by moving upward the small metal pipe (2) in the straight bore until the inner end of the small metal pipe (2) projects over the inside of the furnace, replacing the damaged upper piece (4a) of refractory block with a new upper piece (4a) (hereinafter referred to as a repairing brick) as shown in FIG. 4(b) and filling the remaining portion with a refractory material (16). Thereafter, the small metal pipe (2) is moved du~ walll until the inner end becomes in the same level with the upper surface of the repairing brick (4a).
With the method of FIG. 4, the service life of the gas blast nozzle will be further prolonged compared with its repairing where the lost portion is filled only by a castable refractory material. Additionally, since the small metal pipe (2) is not projecting into the furnace after the repairing, it will be consumed at a reduced rate.
[BRIEF DESCRIPTION OF THE DRAWINGS]
FIG. I illustrates an ~mho~im~nt of gas blast nozzle according to the invention.
FIG. 2 illustrates a method of using the gas blast nozzle of FIG. I.
FIG. 3 illustrates another embodiment of gas blast nozzle according to the invention.
FIG. 4 illustrates a method of using the gas blast nozzle of FIG. 3.
FIG. 5 illustrates a known gas blast nozzle.
FIG. 6 illustrates a known gas blast plug.
[BEST MODE FOR CARRYING OUT THE INVENTION]
A straight bore having an inner diameter of 5 mm was formed through a refractory block (4) as shown in FIG. I(a) in order to provide a gas blast nozzle for feeding gas from the bottom of an electric furnace. The small metal pipe (2) had an inner diameter of 2 mm, an outer diameter of 4 mm and a length of 2 m and was used with a metal coupler (23) as shown in FIG. I(c).
Gas was blown into the molten metal in the furnace at a rate of 30 to IOO liter/min. When the gas blast nozzle (1) had been lost by about 200 mm at the inner end, the gas feeding hose (15) as shown in FIG. l(c) was removed, the small metal pipe (2) was moved upward until the upper end became in the same level with the surface of repaired refractory bottom (11) of the furnace and the lost portion was filled with refractory material. After this ~ -8-repairing, it was coupled with the gas hose (15) again by means of the metal coupler (23). An ordinary refractory material for repairing furnace bottom was used to fill the lost portion of the furnace. In order to prevent the inner end of the small metal pipe (2) from being clogged, gas was continually blown during the operation of filling the refractory material.
After four times to five times of repairing, the small metal pipe (2) was replaced by a new one, and the cycle of usual furnace operation and repairing was further repeated. When moving and/or replacing the small metal pipe (2), it was found in some cases that molten metal had entered the annular gap between the straight bore (3) and the small metal pipe (2) and been solidified there. However, the small metal pipe (2) could be easily moved by striking it from under.
The gas blast nozzle (1) was replaced when the lost portion (8) of the nozzle became as deep as 300 mm, and it was found that the gas blast nozzle (1) according to the invention can withstand more than 300 charges, showing a remarkable improvement in the service life when compared with cv~ Lio--al gas blast nozzles that was replaced at every 50 charges.
Also, a gas blast nozzle having a split refractory block as shown in FIG. 3 was also tested to see the improvement in the service life. Table 1 shows some of the results of their service life obtained.
21 ~554 1 g Table 1 Case 1 2 type of nozzle two piece type (FIG. 3) one piece type (FIG. 1) repairing method using repairing brick using only filling (4a) and filling refractory refractory service life from replacement to the 1st 170-200 (hrs.) 170 - 200 (hrs.) repair service life from repairing to the next 170-200 (hrs.) 80 - 100 (hrs.) repairinF
number of repairing from replacement to the 5 times 4 times nex. replacement ser~ ice life from rep acement to the next 1150 (hrs.) 550 (hrs.) rep acement Case 1 in Table 1 represents the use of a split type gas blast nozzle as shown in FIG. 3 which was repaired by using a repairing brick (4a) and filling refractory material. After 170 to 200 hours of gas blast operation, the upper piece of refractory block (4a) was removed and the small metal pipe (2) was moved upward. Thereafter, a new upper piece of refractory block (4a) was connected on the lower piece of refractory block (4b) with motor applied therebetween. At the same time, the annular gap between the small metal pipe (2) and the straight bore (3) of the refractory block was also filled with a non-porous refractory material.
And thereafter, the lost portion was filled with a filling material to complete the first repair. Thus, the gas blast nozzle was repaired after every 170-200 operating hours for the second through fifth repairs. The (upper) tuyere-forming brick (6) was also replaced at the even-numbered repairs.
The upper piece of refractory block (4a) had an original length of 200 mm, although the remaining length was between 50 and 100 mm at the ~1 q554l ~ - 10-time of each repair. The nozzle was replaced 170 to 200 hours after the fifth repair, then the lower piece of refractory block (4b) was nnrlllmAgpd and could be used further.
Ca~e 2 in Table 2 represents the use of a one piece nozzle as shown in FIG. 1, which was repaired only by means of a filling refractory material.
After 170 to 200 hours of gas blast operation, the small metal pipe (2) was moved upward by a length greater than the height of the lost portion of the nozzle and the lost portion was filled with a filling refractory material.
Then, the gas blast nozzle was repaired after every 80 to 100 operating hours for the second and fourth repairs. At this time, the nozzle had been lost by 2~0 to 300 mm, and they vere replaced along with the upper tuyere-forming bricks to the new ones, because they were so damaged that the time required for further repairing seemed to exceed the specified repairing time.
A~ seen from Table 1, the service life of repaired nozzle, the number of repairs and the service life from replacement to the next rpp~ pmpnt had been increased in Case 1.
[Advantages of the Invention]
The gas blast nozzle according to the invention can reduce the frequency of replacement of the gas blast nozzle, and can reduce the down time of the furnace operation. A~tlit:ion~lly, it reduces the work load of the replacing operation under adverse working r~nl1iti~m~ and is free from the problem of gas leaking through the gas blast nozzle. Finally, it can be applied at reduced cost because it is structurally simple.
AND
METHOD OF USING THE SAME
[Technical Field]
This invention relates to a gas blast nozzle for molten metal in a smelting furnace such as an electric furnace or another refining furnace.
More particularly, it relates to a gas blast nozzle for molten metal that can be repaired easily and a method of using the same.
[Background Art]
FIG. ~ of the accompanying drawings illustrates examples of known gas blast nozzle. In FIG. 5, (a), (b) and (c) ~ ,e~;tiv~ly show a single pipe nozzle, a double pipe nozzle and a multi-pipe nozzle, and (d) shows a porous plug. In FIG. ~, reference numerals (10) and (11) L~e.liv~ly denote a gas feed hose and a l~L~IotuL,~ in furnace bottom, whereas (17) and (18) respectively denote a cooling gas feed pipe and a porous brick. A multi-pipe nozzle of (c) in FIG. 5 may be realized by burying a plurality of small metal pipes in a l~L~ y block and such multi-pipe nozzle has been popularly used for electric furnaces because fine and evenly sized gas bubbles can be produced in molten metal by means of the multi-pipe nozzle.
As gas is blown into molten metal through a gas blast nozzle in a refining furnace, the inner side of refractory of the furnace becomes remarkably worn away in an area ~ul~Ju..dillg the gas blast nozzle as shown (8) in FIG. 2(a) as the molten metal in the furnace is fiercely moved by the gas in an area near the gas blast nozzle. When the lost portion (8) has grown too big, the gas blast nozzle has to be replaced, which results in 21 9~
' - 2 -sl~p~n-ling of the operation of the furnace. Furthermore, such a nozzle replacing operation has to be conducted in an adverse environment and, therefore, it i8 not reromml~nl1~d to replace the gas blast nozzle frequently.
Japanese Pàtent Application Laid-Open Publication No. 58-81937 discloses "a gas blast plug comprising a refractory nozzle block having bore therethrough and a small metal pipe placed in the bore with an annular gap to an inner surface of the bore.
FIG. 6 of the accompanying drawings illustrates the gas blast plug according to the above. Referring to FIG. 6(a), an annular gap is formed between the inner surface of the bore and outer surface of the small metal pipe (2), such that a thickness of the annular gap is as thin as not leak molten metal. In FIG. 6(a), a gas feed hose (not shown) is connected to the small metal pipe (2). The arr~ngl~m~nt shown in FIG. 6 seemed to be effective for prolong a service life of gas blast nozzle, since the gas blast nozzle can be repaired when it is partly lost during its usage, and can be served for long term without replacing it.
However, the inventors of the present invention have found that, when the gas blast plug according to the above is used in electric refining furnace, the gas tends to move into the annular gap rather than entering into the molten metal as shown in FIG. 6(b). When a supply of the gas from the small metal pipe (2) is at a low rate and the gas is blown in from the bottom of the furnace, a big statistic pressure of the molten metal at the bottom of the furnace may resist the gas entering into the molten metal, and the gas move more easily into the annular gap than into the molten metal.
However, the above invention does not provide a solution to this problem.
[DISCLOSURE OF THE INVENTION]
The present invention provides a gas blast nozzle that .,.i..;. .i~.s the '' -3-down time of a furnace for replacing the gas blast nozzle because it seldom requires the repl~rPmrnt, reduces the work load of the replacing operation under adverse working conditions and is free from the problem of gas leaking through the gas blast nozzle.
FIG. I ofthe ~rr~mp~nying drawings shows a gas blast nozzle according to the invention. In FIG. l, (a) is a longitudinal sectional view of the gas blast nozzle by itself and (b) is also a longitudinal sectional view of the gas blast nozzle showing how it is arranged in the bottom of a furnace, whereas (c) is also a longitudinal sectional view illustrating with a coupler for connf~rting it with a gas feed hose.
According to the invention, there is provided a gas blast nozzle for molten metal comprising a refractory block (4~ having a narrow straight bore (3) being bored from the inside to the outside of a furnace, a tubular metal fitting (22) formed in one body with the refractory block (4), a small metal pipe (2) arranged slidably through the straight bore (3) of said refractory block (4) and a metal coupler (23) for ronn~rting a gas hose (15) to an end of said tubular metal fitting (22), cLa~ d in that an outer end portion of said small metal pipe (2) is made to penetrate through a rubber block (14) in said metal coupler (23) and the gas (12) fed to the metal coupler (23) is blown into the molten metal in the furnace from the inner end of said small metal pipe (2).
The tubular metal fitting (22) is tubular at an end and has a saucer-like profile at the other end to snugly receive the bottom of the refraciory block (4) so that the refractory block (4) is f tted and bonded to the tubular metal fitting (22) at its bottom to make them in one body with each other.
Since the refractory block (4) and the tubular metal fitting (22) are made in one body with each other as well as the small metal pipe is made to ~ 1 ~5~ ~
'~ -4-penetrate through the rubber block, gas is securely prevented from leaking through the annular gap between the small metal pipe (2) and the refractory block (4) unlike the case of FIG. 6(b).
As seen from FIG. l(c), the tubular end of the metal fitting (22) is ~onne-~ted to an end of the metal coupler (23), and the other end of the metal coupler (23) is connected to a gas hose (15).
The outer end of the small metal pipe (2) is made to penetrate the rubber block (14) and open for the gas hose (15). The gap between the outer periphery of the small metal pipe (2) and the inner surface of the metal coupler (23) is sealed by the rubber block (14) so that all the gas (12) fed in from the gas hose (15) is blown into the small metal pipe (2).
While FIG. 1 shows a gas blast nozzle (1) having a single small metal pipe (2), a gas blast nozzle according to the invention may alternatively .
comprise a plurality of small metal pipes (2) in such a way that the gap between each of the small metal pipes (2) and the colle~ line metal coupler (23) is filled with a rubber block (14) so that all the gas fed in may be blown into the small metal pipes (2) regardless of the number of small metal pipes (2).
As shown in FIG. l(b), the gas blast nozzle (1) is fitted to the tuyere-forming brick (6) at the L~r ~ Wy bottom (11) of the furnace and secured to the outer shell (19) of the furnace by means of a securing ring (21) and a lock member (20). At the time, the gap between the nozzle and the tuyere-forming bricks is filled with some castable refractory substance (5).
The small metal pipe (2) may be a stainless steel pipe having an inner diameter of 1 to 2 mm, although the inner diameter and the number of pipes may be selected depending on the gas flow rate. Additionally, the small metal pipe may be a single pipe or a double pipe. Note that the inner 2 ~
diameter of the straight bore (3) is made greater than the outer diameter of the small metal pipe (2) by 0 to 4 mm in order to allow the small metal pipe (2) smoothly to move vertically.
FIG. 2 illustrates a method of using the gas blast nozzle (1) according to the invention. A gas blast nozzle (1) according to the invention is worn and wears away the inner refractory during its usage to produce a lost portion (8) as shown in FIG. 2(a). According to the invention, the lost portion (8) is repaired by moving upward the small metal pipe (2) in the straight bore (3) until the inner end of the small metal pipe (2) projects over the inside of the furnace as shown in FIG. 2(b).
Then, the lost portion (8) is filled with a refractory material (16) without closing the inner end of the small metal pipe (2) as shown in FIG.
2(c). In FIG. 2(c), the inner end of the small metal pipe (2) is projecting overthe inner surface of the furnace after the lost portion is filled with the refractory material (16). And the inner end of the small metal pipe (2) would not be buried nor clogged by this projection even if in an usual repairing apparatus of the furnace lining such as a sand slinger is used to fillthe lost portion (8) with an ordinary refractory material for repairing of the lining of the furnace.
Thus, with a gas blafft nozzle (1) according to the invention, the gas blast nozzle and its peripheral area can be repaired easily, if necessary, in the routine operation for ml3int~ining the furnace bottom and the furnace wall, which consequently prolong the service life of the gas blast nozzle 80 that the frequency of replacing the gas blast nozzle will be remarkably reduced.
When gas is blown into the molten metal in the furnace after filling the lost portion as shown in FIG. 2(c), the projecting portion of the small 2 ~ 9 ~
metal pipe (2) i8 immediately molten away and the inner end of the gas blast nozzle will show a profile as shown in FIG. l(b). And, the gas blast nozzle operates to blow gas into the molten metal as stably as before.
FIG. 3 illustrates another embodiment of gas blast nozzle according to the invention. In FIG. 3, (a) is a longitudinal sectional view of the gas blast nozzle and (b) is also a longitudinal sectional view showing how the gas blast nozzle is arranged in the bottom of a furnace.
The gas blast nozzle of FIG. 3(a) differs from that of FIG. l(a) in that the refractory block (4) is divided into upper and lower pieces. Otherwise, it is the same as its counterpart of FIG. l(a). As described earlier in FIG. l(c), the tubular metal fitting (22) is coupled at its outer end to a gas hose (15) bymeans of a metal coupler (23) and the annular gap around the small metal pipe (2) is sealed by a rubber block (14).
As shown in Fig. 3(b), the gas blast nozzle is also fitted to the tuyere-forming bricks (6) at the refractory bottom (11) of the furnace and secured to the outer shell (19) of the furnace by means of a securing ring (21) and a lock member (20). Also, the gap between the nozzle and the tuyere-forming bricks is filled with some castable refractory substance.
FIG. 4 illustrates a method of using the gas blast nozzle illustrated in FIG. 3. The lost portion (8) in FIG. 4(a) is repaired by moving upward the small metal pipe (2) in the straight bore until the inner end of the small metal pipe (2) projects over the inside of the furnace, replacing the damaged upper piece (4a) of refractory block with a new upper piece (4a) (hereinafter referred to as a repairing brick) as shown in FIG. 4(b) and filling the remaining portion with a refractory material (16). Thereafter, the small metal pipe (2) is moved du~ walll until the inner end becomes in the same level with the upper surface of the repairing brick (4a).
With the method of FIG. 4, the service life of the gas blast nozzle will be further prolonged compared with its repairing where the lost portion is filled only by a castable refractory material. Additionally, since the small metal pipe (2) is not projecting into the furnace after the repairing, it will be consumed at a reduced rate.
[BRIEF DESCRIPTION OF THE DRAWINGS]
FIG. I illustrates an ~mho~im~nt of gas blast nozzle according to the invention.
FIG. 2 illustrates a method of using the gas blast nozzle of FIG. I.
FIG. 3 illustrates another embodiment of gas blast nozzle according to the invention.
FIG. 4 illustrates a method of using the gas blast nozzle of FIG. 3.
FIG. 5 illustrates a known gas blast nozzle.
FIG. 6 illustrates a known gas blast plug.
[BEST MODE FOR CARRYING OUT THE INVENTION]
A straight bore having an inner diameter of 5 mm was formed through a refractory block (4) as shown in FIG. I(a) in order to provide a gas blast nozzle for feeding gas from the bottom of an electric furnace. The small metal pipe (2) had an inner diameter of 2 mm, an outer diameter of 4 mm and a length of 2 m and was used with a metal coupler (23) as shown in FIG. I(c).
Gas was blown into the molten metal in the furnace at a rate of 30 to IOO liter/min. When the gas blast nozzle (1) had been lost by about 200 mm at the inner end, the gas feeding hose (15) as shown in FIG. l(c) was removed, the small metal pipe (2) was moved upward until the upper end became in the same level with the surface of repaired refractory bottom (11) of the furnace and the lost portion was filled with refractory material. After this ~ -8-repairing, it was coupled with the gas hose (15) again by means of the metal coupler (23). An ordinary refractory material for repairing furnace bottom was used to fill the lost portion of the furnace. In order to prevent the inner end of the small metal pipe (2) from being clogged, gas was continually blown during the operation of filling the refractory material.
After four times to five times of repairing, the small metal pipe (2) was replaced by a new one, and the cycle of usual furnace operation and repairing was further repeated. When moving and/or replacing the small metal pipe (2), it was found in some cases that molten metal had entered the annular gap between the straight bore (3) and the small metal pipe (2) and been solidified there. However, the small metal pipe (2) could be easily moved by striking it from under.
The gas blast nozzle (1) was replaced when the lost portion (8) of the nozzle became as deep as 300 mm, and it was found that the gas blast nozzle (1) according to the invention can withstand more than 300 charges, showing a remarkable improvement in the service life when compared with cv~ Lio--al gas blast nozzles that was replaced at every 50 charges.
Also, a gas blast nozzle having a split refractory block as shown in FIG. 3 was also tested to see the improvement in the service life. Table 1 shows some of the results of their service life obtained.
21 ~554 1 g Table 1 Case 1 2 type of nozzle two piece type (FIG. 3) one piece type (FIG. 1) repairing method using repairing brick using only filling (4a) and filling refractory refractory service life from replacement to the 1st 170-200 (hrs.) 170 - 200 (hrs.) repair service life from repairing to the next 170-200 (hrs.) 80 - 100 (hrs.) repairinF
number of repairing from replacement to the 5 times 4 times nex. replacement ser~ ice life from rep acement to the next 1150 (hrs.) 550 (hrs.) rep acement Case 1 in Table 1 represents the use of a split type gas blast nozzle as shown in FIG. 3 which was repaired by using a repairing brick (4a) and filling refractory material. After 170 to 200 hours of gas blast operation, the upper piece of refractory block (4a) was removed and the small metal pipe (2) was moved upward. Thereafter, a new upper piece of refractory block (4a) was connected on the lower piece of refractory block (4b) with motor applied therebetween. At the same time, the annular gap between the small metal pipe (2) and the straight bore (3) of the refractory block was also filled with a non-porous refractory material.
And thereafter, the lost portion was filled with a filling material to complete the first repair. Thus, the gas blast nozzle was repaired after every 170-200 operating hours for the second through fifth repairs. The (upper) tuyere-forming brick (6) was also replaced at the even-numbered repairs.
The upper piece of refractory block (4a) had an original length of 200 mm, although the remaining length was between 50 and 100 mm at the ~1 q554l ~ - 10-time of each repair. The nozzle was replaced 170 to 200 hours after the fifth repair, then the lower piece of refractory block (4b) was nnrlllmAgpd and could be used further.
Ca~e 2 in Table 2 represents the use of a one piece nozzle as shown in FIG. 1, which was repaired only by means of a filling refractory material.
After 170 to 200 hours of gas blast operation, the small metal pipe (2) was moved upward by a length greater than the height of the lost portion of the nozzle and the lost portion was filled with a filling refractory material.
Then, the gas blast nozzle was repaired after every 80 to 100 operating hours for the second and fourth repairs. At this time, the nozzle had been lost by 2~0 to 300 mm, and they vere replaced along with the upper tuyere-forming bricks to the new ones, because they were so damaged that the time required for further repairing seemed to exceed the specified repairing time.
A~ seen from Table 1, the service life of repaired nozzle, the number of repairs and the service life from replacement to the next rpp~ pmpnt had been increased in Case 1.
[Advantages of the Invention]
The gas blast nozzle according to the invention can reduce the frequency of replacement of the gas blast nozzle, and can reduce the down time of the furnace operation. A~tlit:ion~lly, it reduces the work load of the replacing operation under adverse working r~nl1iti~m~ and is free from the problem of gas leaking through the gas blast nozzle. Finally, it can be applied at reduced cost because it is structurally simple.
Claims (4)
1. A gas blast nozzle for molten metal comprising a refractory block (4) having a narrow straight bore (3) being bored from the inside to the outside of a furnace, a tubular metal fitting (22) formed in one body with the refractory block (4), a small metal pipe (2) arranged slidably through the straight bore (3) and a metal coupler (23) for connecting a gas hose (15) to an end of said tubular metal fitting (22), characterized in that an outer end portion of said small metal pipe (2) is made to penetrate through a rubber block (14) in said metal coupler (23) and the gas (12) is fed to the outer end of the small metal pipe (2) and is blown into the molten metal from the inner end of the small metal pipe (2).
2. A method of using a gas blast nozzle for molten metal as defined in claim 1, characterized in that, in repairing a lost inner portion (8) of the gas blast nozzle and a surrounding area, a refractory material is filled into the lost portion (8) after moving the small metal pipe (2) upward through the straight bore (3) to project its inner end over the inside of the furnace in order to prevent its inner end from being clogged by a refractory material.
3. A gas blast nozzle for molten metal according to claim 1, characterized in that said refractory block (4) is composed by two or more refractory pieces being piled vertically.
4. A method of using a gas blast nozzle for molten metal as defined in claim 3, characterized in that, in repairing a lost inner portion (8) of the gas blast nozzle and a surrounding area, the used upper refractory piece (4a) is changed to a new upper refractory piece (4a), and a refractory material is filled into the lost portion (8) after moving the small metal pipe (2) upward through the straight bore (3) to project its inner end over the inside of the furnace in order to prevent its upper end from being clogged by a refractory material.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7-126107 | 1995-05-25 | ||
| JP12610795 | 1995-05-25 | ||
| JP7324447A JPH0941024A (en) | 1995-05-25 | 1995-12-13 | Gas blowing nozzle into molten metal and its using method thereof |
| JP7-324447 | 1995-12-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2195541A1 true CA2195541A1 (en) | 1996-11-28 |
Family
ID=26462336
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002195541A Abandoned CA2195541A1 (en) | 1995-05-25 | 1996-05-23 | Nozzle for blowing gas into molten metal and usage thereof |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0776983B1 (en) |
| JP (2) | JPH0941024A (en) |
| KR (1) | KR100349870B1 (en) |
| CN (1) | CN1053015C (en) |
| CA (1) | CA2195541A1 (en) |
| DE (1) | DE69615508T2 (en) |
| WO (1) | WO1996037632A1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10347947B4 (en) * | 2003-10-15 | 2007-04-12 | Maerz-Gautschi Industrieofenanlagen Gmbh | Industrial furnace and associated nozzle element |
| JP4351715B2 (en) * | 2007-09-10 | 2009-10-28 | 新日本製鐵株式会社 | Tuna structure of melting furnace |
| KR101310737B1 (en) * | 2008-07-28 | 2013-09-25 | 신닛테츠스미킨 카부시키카이샤 | Nozzle for continuous casting |
| ES2572686T3 (en) * | 2014-05-05 | 2016-06-01 | Refractory Intellectual Property Gmbh & Co. Kg | Refractory ceramic element with gas scanning |
| PL3023173T3 (en) * | 2014-09-29 | 2018-12-31 | Refractory Intellectual Property Gmbh & Co. Kg | Attachment device for a cylindrical ceramic hollow body and fireproof ceramic gas purging plug with such an attachment device |
| WO2017103959A1 (en) * | 2015-12-17 | 2017-06-22 | 東京窯業株式会社 | Bottom-blowing plug with improved workability |
| JP7107141B2 (en) * | 2018-09-27 | 2022-07-27 | 日本製鉄株式会社 | Converter tuyere structure |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5952216B2 (en) * | 1979-05-24 | 1984-12-18 | 住友金属工業株式会社 | How to replace the gas blowing nozzle |
| JPS5881937A (en) * | 1981-11-12 | 1983-05-17 | Kawasaki Steel Corp | Plug for injecting refining gas |
| JPS5952216A (en) * | 1982-09-20 | 1984-03-26 | Canon Inc | Plural beam optical deflector |
| DE3311617C1 (en) * | 1983-03-30 | 1984-10-25 | Messer Griesheim Gmbh, 6000 Frankfurt | Method and device for rinsing a molten metal, in particular steel, in a ladle |
| JPS6030834A (en) * | 1983-07-14 | 1985-02-16 | Fuji Electric Co Ltd | Disk brake device |
| DE3545763A1 (en) * | 1985-12-21 | 1987-06-25 | Didier Werke Ag | GAS PUMP PLUG FOR A MELTING VESSEL |
| JPS6489947A (en) * | 1987-09-30 | 1989-04-05 | Aisin Seiki | Generating set for vehicle |
| JPH0630834Y2 (en) * | 1987-12-07 | 1994-08-17 | 川崎炉材株式会社 | Gas blown tuyere structure for molten metal containers |
| JPH01172507A (en) * | 1987-12-28 | 1989-07-07 | Nippon Steel Corp | Construction for fitting triple pie tuyere to furnace bottom |
| JPH0497835U (en) * | 1991-01-11 | 1992-08-25 | ||
| DE4213007C1 (en) * | 1992-04-21 | 1993-12-16 | Tech Resources Pty Ltd | Method and device for sealing nozzles in the surrounding refractory lining |
| JP4610946B2 (en) * | 2004-06-30 | 2011-01-12 | 株式会社島津製作所 | Odor identification method |
-
1995
- 1995-12-13 JP JP7324447A patent/JPH0941024A/en active Pending
-
1996
- 1996-05-23 EP EP96914400A patent/EP0776983B1/en not_active Expired - Lifetime
- 1996-05-23 CN CN96190548A patent/CN1053015C/en not_active Expired - Fee Related
- 1996-05-23 DE DE69615508T patent/DE69615508T2/en not_active Expired - Fee Related
- 1996-05-23 WO PCT/JP1996/001356 patent/WO1996037632A1/en active IP Right Grant
- 1996-05-23 JP JP53555896A patent/JP3894502B2/en not_active Expired - Lifetime
- 1996-05-23 CA CA002195541A patent/CA2195541A1/en not_active Abandoned
- 1996-05-23 KR KR1019970700435A patent/KR100349870B1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| DE69615508D1 (en) | 2001-10-31 |
| CN1154720A (en) | 1997-07-16 |
| JP3894502B2 (en) | 2007-03-22 |
| DE69615508T2 (en) | 2002-05-29 |
| KR100349870B1 (en) | 2003-01-06 |
| EP0776983B1 (en) | 2001-09-26 |
| EP0776983A4 (en) | 1998-09-09 |
| KR970704892A (en) | 1997-09-06 |
| CN1053015C (en) | 2000-05-31 |
| WO1996037632A1 (en) | 1996-11-28 |
| EP0776983A1 (en) | 1997-06-04 |
| JPH0941024A (en) | 1997-02-10 |
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