US3411528A - Stopper for ladle with air-cooled head - Google Patents

Description

Nov. 19, 1968 KATsUHlDE MACHIYAMA ETAL 3,411,528

STOPPER FOR LADLE WITH AIR-COOLED HEAD Filed June l, 1966 2 Sheets-Sheet 1 ATTORNEY) Nov. 19, 1968 KATsuHlDE MACHIYAMA ETAL 3,411,528

STOFPER FOR LADLE WITH AIR-COOLED HEAD Filed June l, 1966 2 Sheets-Sheet 2 INVENTORSv ATTORNEYs United States Patent O 3,411,528 STOPPER FOR LADLE WITH AIR-COOLED HEAD Katsuhide Machiyama and Yoshro Yanagda, Hikari Japan, assignors to Yawata Iron 8L Steel Co., Ltd., Tokyo, Japan, a corporation of Japan Filed June 1, 1966, Ser. No. 554,394 Claims priority, application Japan, June 3, 1965, 40/ 44,281 Claims. (Cl. 137-340) ABSTRACT OF THE DISCLOSURE A stopper for a ladle for a molten metal. The stopper has a cylindrical hollow sleeve with a first tubular member in said sleeve and having a flange on the outside thereof overlapping at least a portion of the sleeve. A second tubular member is threadedly connected with said first tubular member and has a flange at its lower end. A head is provided around the second tubular member and is engaged with the first tubular member and is held in engagement by the flange on the lower end of the second tubular member. A cooling air introducing pipe extends into the space within the tubular members with a passage left from the returning cooling air.

This invention relates in general to an improvement of the stopper for -a ladle and more particularly to a stopper for a steel ladle with an air-cooled head.

The stopper for a steel ladle which is used in steel making or other plants, comes in three general types according to the structure of its head, that is, the cottor type (or the pin type), the screw type and the rotolok type.

The cotter type has the following construction. The rod of the bottom-sleeve and that of the head are connected by a cotter; the weight of said sleeve is supported by a flange set on the rod of the head; the top of the head is filled with mortar. The screw type is so constructed that a flange set on the rod of the bottom-sleeve supports the weight of said sleeve, and the head and its rod are threadedly connected. The rotolok type is constructed in such manner that the rod has no flange, but the bottom-sleeve and the head are connected only by a nipple.

The disadvantage of the cotter type is that because of its structure, air-cooling of the head is impossible, and as the rod of the bottom-sleeve has no flange as mentioned above, the weight of the sleeve falls entirely on the head, and therefore, it is supported by the flange set on the rod of thehead, causing 'casual breakage of the head while the stopper is operated at 'high temperatures. Due to errors in making the cotter and the bottom-sleeve, there may be a gap between them, which allows molten steel to come in, possibly causing the disconnection of the head. Because of the above difficulties, the cotter is now not popular.

As regards the screw type, it has the flange set on the rod of the sleeve, therefore, it is free from the difficulty that is inherent in the cotter type that the weight of the sleeve works on the head. However, the screw type is not exempt from another difficulty which is caused by the connection of materials of different kinds by screw threads, that is, the head which is made of a refractory material and its rod which is made of a metal, are subject to different thermal expansion rates, which means that as they are heated at a high temperature, the difference of thermal expansion rates causes deformation of the screwthreads, and as the stopper is operated at a high frequency, the connection loosens, producing a gap between the bottom-sleeve and the head, which allows molten steel to come in, and will possibly cause the disconnection of the head. The higher the temperature of molten steel and the 3,411,528 Patented Nov. 19, 1968 F ICC? frequency of the operation of the stopper, the higher the possibility of such an accident. It is theoretically possible for the screw type to use a pipe as a substitute for the rod of the sleeve so as to cool the bottom-sleeve by air, but the cooling of the head which is more important for such purpose, cannot be effected, as it is impossible to make holes on the rod of the head in sufficient number to conduct air for cooling of the head because of the limited strength of the threads. Furthermore, the threaded connection alone is not sufficient for fixing the head to the sleeve; if there is an error in making the thread groove on the head, there will be produced a gap between the bottom-sleeve and the head, which will possibly cause an accident. As for rotolok type, the strength of the nipple constitutes a problem. Besides, as no flange is set on the rod, the weight of the bottom-sleeve entirely works on the head, causing the same diculty as with the cotter type.

This invention seeks to remove nearly all troubles inherent in such conventional types of stopper as mentioned above. The stopper of this invention is so constructed as to make the cooling even of the inner part of the head effective by the use of hollow rods having a flange and threaded portion respectively for the sleeve `and the head, and also to connect the sleeve and the head tightly without producing a gap between them by the use of hollow rods of the sleeve and of the head which are connected by a threaded connection.

An object of this invention is to provide a stopper for the ladle or the like which can be yused continuously for a considerable time in the operation of producing metal or steel ingots by pouring molten metals or particularly molten steel into mold from the steel ladle or the like, without melting and breakage to which the stopper for this purpose is liable due to its repeated immersion in molten metals or steel of high temperature.

Another object of this invention is to provide a structure of a stopper for the ladle or the like for use in the operation of producing metal or steel ingots by pouring molten metal, or particularly molten steel into molds from the steel ladle or the like, such structure being simple and easy to construct and connecting the sleeve and the head so tightly as to produce no gap between them or a very little one, if any.

The invention will now be explained with reference to the accompanying drawings, in which:

FIG. 1 is a cross-section of the head of the stopper of the present invention.

FIG. 2 is a cross-sectional -view on line II-II in FIG- URE l.

FIG. 3 shows a ladle apparatus with the stopper of FIGURE 1 therein.

The stopper of this invention is so constructed that a first tubular member 8 in the bottom-sleeve has a flange 3 on the lower end thereof, yand a secondptubular member 4 of the head has a flange 5 thereon and is connected by a screw thread connection 9 to the tubular member 8, pipe 7 having notches 10 at its lower end is inserted into said tubular members 8 and 4 in such a manner that a space is left between them for introducing air to cool the inside of head 1, while the connection of the cylindrical, hollow bottom-sleeve 2 and the head 1 is so tight as to leave no gap between them.

In further regard to the air-cooling of the head 1, as both the tubular member 8 of the bottom-sleeve and the tubular member 4 of `the head which is connected with the tubular member 8, are hollow, the pipe 7 for introducing cooling air is inserted into a space within the tubular member until it reaches the ange 5 on the tubular member 4 of the head, making it possible to send cooling air to this place and thus cool the head from inside. At the lower end, the pipe 7 has notches 10, so that after cooling the head 1, air turns upward through the notches 10, which flow is indicated by the arrow in the drawings. As the stopper of this invention is constructed as mentioned above, it is possible to cool by air the inside of the head; otherwise the tubular member of the head is subject to melting or breakage due to high temperatures and impacts during the operation which lasts for a considerable time. In place of providing the notches 10 at the lower end of the pipe 7 for introducing cooling air, anything can be interposed for producing a space between said pipe 7 and the flange 5. It is advisable to provide a taper at the upper end of the tubular member 4 of the head, so as to make insertion of the pipe 7 easier.

Regarding the tubular member 8 of the bottom-sleeve, the weight of the sleeve 2 is supported by the ilange 3 at the lower end of the tubular member, therefore there is no such difficulty that the weight thereof falls on the head 1. The hollow tubular member 4 is connected by screw threaded connection 9 with the hollow tubular member 8 of the sleeve, thereby connecting the bottom-sleeve 2 with the head 1. Moreover, -both tubular members 8 and 4 are made of steel of the same quality, which means that there is no difference in thermal expansion rate between them. Therefore, there will be no possibility of the threaded connection loosening during operation. The

threaded connection holds the sleeve 2 and the head 1 together so tightly that molten steel will not enter between thern. Even if a gap is produced between these parts,

they can be threaded further together to ll it up. If a groove or hole 6 is made on the bottom of the ange 5, the threading of the hollow tubular member 4 will be made easier and more effective.

The flanges 3 and 5 are welded on the tubular members 8 and 4, respectively. In addition, a threaded washer 13 is threaded onto the tubular member 4 of the head 1 under the ange 3, to X the head 1, together with the flange 5. By use of the washer 13, the head 1 and the sleeve 2 can be connected firmly without diiculty permitting almost no gas to escape between them. However, this washer 13 is not indispensable. A piece of a refractory material 11 is threaded into the head 1 at the lower end, and is of same quality as the head itself. A groove or hole 12 makes easier the connection of the refractory material 11 with the head.

A ladle apparatus with the stopper of the present invention is shown in FIGURE 3. In the drawing, cooling air is introduced into the pipe 7 through the out-side pipe 23 on the ladle 14 and the gooseneck 16, The stopper of the present invention is Xed on the gooseneck 16 with nuts |19. It moves up and down in the ladle 14 by the operating device consisting of the cylinder 18 and the slide 17 which are mounted on the ladle 14, so that it opens or stops pouring of molten steel through the nozzle 15.

As the stopper of this invention is constructed as mentioned above, it can be used continuously for a considerable time in the molding of molten metals or particularly molten steel, in combination with the ladle 0r the like.

What we claim is:

1. A stopper for a ladle, comprising a cylindrical hollow sleeve, a rst tubular member in said sleeve and having a ange on the outside thereof overlapping at least a portion of `said hollow sleeve, a second tubular member threadedly connected with said first tubular member and having a flange at its lower end, a head around said second tubular member and engaged with said rst tubular member and held in engagement therewith by said ange on the lower end of said second tubular member which ange overlaps at least a portion of said head, and a cooling air introducing pipe extending into the space within said tubular members and spaced from the interior walls of the tubular members to leave a return passage for the cooling air.

2. A stopper as claimed in claim 1 in which the lower end of said cooling air introducing pipe is in contact with the flange on said sec-ond tubular member, and said lower end of said pipe has notches therein permitting escape of air therethrough.

3. A stopper as claimed in claim 1 in which the lower end of said cooling air introducing pipe is spaced from the ange on lsaid second tubular member, means between said end of said pipe and said flange for maintaining said spacing.

4. A stopper as claimed in claim 1 in which a washer is provided around said second tubular member between said head and said first tubular member.

5. A stopper as claimed in claim 1 in which said head has a plug of refractory material of the same quality as the material of said head threaded into the lower end of said head.

References Cited UNITED STATES PATENTS 698,474 4/1902 Ebbs 137-340 XR 1,658,292 2/1928 Kniskern 137-340 1,953,611 4/1934 Jardine 137-340 XR 2,005,311 6/1935 Belding 137-340 XR 2,575,875 11/1951 Johnson 137-340 2,941,821 6/1960 Klee 137-340 XR 2,994,338 8/1961 Wilson 137-340 FOREIGN PATENTS 1,106,572 5/1961 Germany.

SAMUEL SCOTT, Primary Examiner.

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