US3288453A - Temperature compensating mounting for basic oxygen furnace - Google Patents

Description

Nov. 29, 1966 c, BUESING ET AL 3,238,453

TEMPERATURE COMPENSATING MOUNTING FOR BASIC OXYGEN FURNACE Filed NOV. 12, 1963 FEW/M United States Patent TEMPERATURE COMPENSATING MOUNTING FOR BASIC OXYGEN FURNACE Arthur C. Buesing and Bela Vitez,'Milwaukee, Wis., as-

siguors to Allis-Chalmers Manufacturing Company, Milwaukee, Wis.

Filed Nov. 12, 1963, Ser. No. 322,817

1 Claim. (Cl. 26636) This invention pertains to a basic oxygen furnace and more particularly to a means for connecting the furnace to laterally extending trunnions which permit tilting the furnace to remove the contents contained therein.

Basic oxygen furnaces or vessels are utilized to produce steel and range in size from vessels of 150 to 300 tons capacity. Vessels are designed for 360 degrees rotation. Initially, the vessel must be turned approximately 55 degrees from the vertical toward the charging platform to receive the scrap and liquid metal charge prior to blowing. During the blow, the vessel is in a vertical position. Following the blowing operation, it must be tilted in the opposite direction toward the pouring ladle to transfer or pour off the molten steel. Following the operation, the transfer ladle is removed and the furnace is tilted to an upside down position, to pour off the slag. It is then returned to the initial 55 degrees position and the charging cycle is resumed.

It is common practice to provide a trunnion ring about the vessel. This ring is provided with laterally extending trunnions which are rotatably contained by the vessel support. The trunnion ring quite frequently is designed to provide an air gap between the outer surface of the vessel and the inner surface of the trunnion ring. This air gap permits expansion of the vessel during the steel making process. It also reduces heat transfer from the vessel to the ring and hence to the trunnion support. However, by providing this air gap between the outer surface of the vessel and the inner surface of the trunnion ring, if the vessel does not expand evenly into engagement with the ring, the vessel is subject to excessive rocking during the tilting operation. This rocking could result in damage to the ring as well as dangerous splashing of the molten metal. To overcome this rocking, various fixed stops are provided between the trunnion ring and the oxygen vessel. These stops in some instances may take the shape of a fixed wedge stop or a vertical wedge may be driven between the trunnion ring and the vessel. None of the previously known stops have exhibited the ability to adjust to unequal pressures due to unequal expansion of the vessel. Unequal expansion results in highly concentrated stresses of such magnitude as to cause cracks in the vessel shell or in some instances rupture of the trunnion ring.

It is applicants intention and a general object of the subject invention to provide a basic oxygen furnace which utilizes a trunnion ring having a stop which insures that the furnace will be maintained and held against excessive rocking while the furnace is being tilted.

A more specific object of the subject invention is to provide a basic oxygen furnace utilizing a trunnion ring with resilient stops between the furnace and the ring to compensate for unequal expansion of the furnace relative to the ring.

A further object of the subject invention is to provide a basic oxygen furnace of the hereinbefore described type with a resilient connection between the furnace and the trunnion ring which permits a predetermined amount of expansion of the furnace before a fixed stop is contacted.

These and other objects of the subject invention will become more fully apparent as the following description is read in light of the attached drawing, wherein:

FliGv 1 is a partial plan view of a basic oxygen vessel incorporating the inventive concept of the invention;

FIG. 2 is a partial side elevation cross section taken along the lines II-II of FIG. 1; and

FIG. 3 is a partial section taken along the lines III-III of FIG. 2.

Referring to the drawing, the basic oxygen furnace or vessel generally designated 6 has an outer shell 7 and an inner wall 8 constructed of any well known heat resistant material. As particularly shown in FIG. 1, the basic oxygen vessel herein disclosed for purposes of illustration is circular in cross section. It should be understood that any convenient cross sectional shape may be utilized.

In view of the circular cross sectional configuration of the vessel disclosed for purposes of illustration, an annular trunnion ring generally designated 9 is utilized. The trunnion ring may be constructed in any conventional manner and is herein shown as having a rectangular cross section best shown in FIG. 2. Opposite ends of the trunnion ring 9 are provided with connection flanges 11 which receive bolts 12 and nuts 13 to connect the ring ends. A pair of diametrically opposed support wheels 10 are rigidly connected to the trunnion ring 9. These wheels are supported in rollers (not shown) to permit tilting of the vessel. The gear 15 may be utilized to control the tilting.

As best shown in FIG. 2, the inside diameter of the trunnion ring 9 is larger than the outside diameter of the vessel 6 so that a space 14 is provided therebetween when the elements are cold. This space is to permit expansion of the vessel relative to the ring as the vessel temperature increases. To this end it is necessary to provide a connection between the ring and the vessel which will permit this relative radial expansion of the vessel relative to the ring.

As herein shown for purposes of illustration, this connection may be effected by providing an annular flange 16 about the outer periphery of the vessel. This flange 16 provides a sliding annular surface 17 and may be strengthened by a plurality of ribs 18 and 19 connected to the vessel in any conventional manner such as by welding. An additional flange 21 spaced from the flange 16 a distance equal to the height of the trunnion ring 9 is also provided about the vessel 6. As herein shown for purposes of illustration, this flange 21 may be C-shaped in cross section and may be connected to the vessel in any conventional manner, however, is herein shown as being releasably connected by means of bolts 22 and nuts 23. Furthermore, to provide a true sliding seat for the trunnion ring 9 an additional ring 24 may be provided. With such an arrangement, the trunnion ring 9 is held about the vessel 6 and between the flanges 16 and 21 in a manner which will permit relative radial movement between the vessel and the ring.

As the temperature of the vessel 6 increases, it will expand radially outwardly to decrease the space 14 between the outside of the vessel and the trunnion ring 9. Because of the extremely high temperature that is attained by the vessel, the space 14 may be as much as four inches. Within this amount of clearance, if the vessel should expand unevenly, which in most cases would be the case, it would not be concentrically located or held within the ring 9. If this should be the case, it is quite likely that as the vessel is tilted about the roller 10, it may rock within the ring which could result in an uncontrolled spilling of a portion of the liquid metal within the vessel. It is, therefore, necessary that the vessel be held within the ring so that it is not permitted to rock during the tilting operation.

To this end, applicants have provided a plurality of resilient retainers 26 to limit the amount of free expansion of the vessel 6 relative to the ring 9. As herein shown for purposes of illustration, each retainer is rigidly connected to the trunnion ring 9 in any conventional manner, such as by welding. In the cold position, as shown in the drawings, a space 27 is provided between the vessel flanges 16 and 21 and the innermost surface 28 of the retainers 26. This space 27 is less than the space 14 so that the resiliency of the retainers 26 will in all cases be utilized when the vessel has obtained the minimum workable temperature. As the vessel expands, the flanges 16 and 21 contact the surfaces 28 of the retainers 26 and exert a pressure thereon. The resilient characteristic of the retainers 26 is such that they will give under the expanding pressure of the vessel; however, they will exert sufiicient holding force on the vessel so as to hold the vessel against rocking when it is tilted.

It should also be noted that the retainers or resilient members are constructed in such a manner that a positive stop is provided. This may be accomplished in any conventional manner and is herein shown as being accom plished by providing a raised portion or boss 29 directly behind the surface 28. This raised portion is spaced a distance 31 from the outer end of the surface 28 so that the resilient characteristics will be experienced until the boss 31 is contacted. Furthermore, the boss 31 will be contacted before the furnace shell 7 contacts the ring 9.

It can thus be seen that even though unequal expansion of the vessel should occur, due to the resiliency of the retainers 26, the vessel will be held so that rocking will not result. It is possible that one side of the vessel will expand so much more than the other side that one or more of the retainers may be ruptured. However, because the ring is spaced further from the furnace, it will not be damaged if some of the retainers do rupture. Furthermore, because of the resiliency of the good retainers on the opposite side of the furnace, the ring will be shifted into engagement with the furnace in the area of the damaged retainers so that the furnace will be adequately held.

From the above description, it can be seen that applicants have developed a means for supporting a basic oxygen vessel which overcomes the problem of rocking inherent in previously known basic oxygen furnace supporting structures. With this arrangement, unequal expansion of the vessel is accommodated by the resilient characteristics of the retainers.

Although only one embodiment of the subject invention has been herein shown and disclosed, other modifications will be apparent to those skilled in the art after this description has been read, and it is intended that all such modifications as come within a reasonable interpretation of the appended claim be covered.

The embodiments of the invention in which an exelusive property or privilege is claimed are defined as follows:

A support for a basic oxygen furnace comprising: a pair of flanges rigidly connected to the outer surface of said furnace providing spaced facing laterally directed annular surfaces; an annular trunnion ring positioned about said furnace in sliding engagement with said spaced surfaces, said trunnion ring having an inside diameter larger than the outside diameter of said furnace; resilient means mounted between said trunnion ring and said furnace and adapted to resiliently resist sliding movement be tween said ring and said furnace only after a predetermined amount of unresisted movement of said furnace; and stop means mounted between said trunnion ring and said furnace and adapted to prohibit relative movement between said trunnion ring and said furnace after a predetermined amount of movement of said resilient means.

References Cited by the Examiner UNITED STATES PATENTS 3,000,621 9/1961 Puxkandl 266-39 3,163,696 12/1964 Johansson et a1. 266-36 3,191,921 6/1965 Johnson 266-36 CHARLIE T. MOON, Primary Examiner.

WHITMORE A. WILTZ, Examiner.

J. M. ROMANCHIK, Assistant Examiner.

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