US3534949A

US3534949A - Steel degassing vessels

Info

Publication number: US3534949A
Application number: US665904A
Authority: US
Inventors: Viktor Mayer; Alfred Weidner; Jorg Kogler
Original assignee: Osterreichisch Amerikanische Magnesit AG
Current assignee: Osterreichisch Amerikanische Magnesit AG
Priority date: 1966-09-15
Filing date: 1967-09-06
Publication date: 1970-10-20
Anticipated expiration: 1987-10-20
Also published as: GB1172128A; SE308537B; DE1583277B1; AT264567B

Description

Oct. 20, 1910 MAYER ETAL 3,534,949

STEEL DEGASSING VESSELS 2 Sheets-Sheet 2 Filed Sept. 6, 1967 INVENTORSZ VIKTOR MAYER AIL FRED WEIDNER JORG KOGLER BY ATTYS.

Patented Oct. 20, 1970 3,534,949 STEEL DEGASSING VESSELS Viktor Mayer, Munich, Germany, Alfred Weidner,

Radenthein, and Jorg Kogler, Villach, Austria, assignors to Osterreichisch-Amerikanische Magnesit Aktiengesellschaft, Radenthein, Carinthia, Austria, a corporation of Carintliia, Austria Filed Sept. 6, 1967, Ser. No. 665,904 Claims priority, application Austria, Sept. 15, 1966, A 8,706/66 Int. Cl. CZlc 7/06 US. Cl. 266-34 3 Claims ABSTRACT OF THE DISCLOSURE An arrangement in steel degassing vessels having a downwardly depending detachable spout for supporting the annular course of refractory bricks located adjacent the spout, the arrangement including a detachable flange for mounting between radially outwardly directed flanges of the vessel and the spout, the detachable flange extending radially inwardly of the vessel flange and supporting a stepped annular course of refractory bricks thereon. The invention includes a method of replacing the annular brick course when relining the spout, the method comprising the steps of removing the detachable flange and the worn brick course, building a course of new brick on the detached flange, securing the new course with a steel strap, and placing the detachable flange and new brick course as a unit between the flanges of the vessel and the relined spout.

The present invention relates generally to steel degassing vessels and relates more particularly to an arrangement and method for the support and replacement of the annular refractory brick course adjacent the detachable spout of such vessels.

A conventional type of steel degassing vessel for degassing fractional quantities of steel comprises a steel container having a conical or spherical bottom from which detachably extends a cylindrical spout, the spout conventionally being eccentrically disposed with respect to the vertical axis of the vessel. The molten steel to be degassed is transferred between a pouring ladle and the degassing vessel through the spout by the periodic application of a vacuum to the degassing vessel. The degassing vessel and the spout are internally lined with refractory brick and the exterior of the spout is covered with a refractory tamping mixture. The spout is detachably connected to the vessel by means of cooperating flanges on both the vessel and the spout which are secured by bolts and wedges. The inlet opening leading from the spout into the degassing vessel is conical, flaring slightly in an upward direction, and is defined in the usual construction by the inner surfaces oftwo superimposed annular courses of bricks.

During operation, the bricks lining the spout rapidly become Worn and the spout must be removed from time to time to permit replacement of the brick lining. Similarly, the two annular courses of bricks at the inlet opening of the vessel wear rapidly with the lower annular course sustaining particularly severe wear. It is thus usually necessary to renew this lower annular brick course during every second relining of the spout. In order to return the vessel to service as quickly as possible, the replacement of the lower annular brick course is carried out while the vessel is at elevated temperatures and with the conventional vessel construction is a diflicult and time consuming task. Contributing to the difficulty is the radially inwardly directed portion of the vessel flange upon which the stepped bricks of the lower annular course are supported. The proper placement of the bricks on this flange is an awkward task when the vessel is hot. Furthermore, due to the wedge shape of the bricks, an opening must be formed in the flange to permit the last brick to be inserted, the opening causing an undesirable weakening of the vessel flange.

To overcome the drawbacks of the conventional type of degassing vessel described above, the present invention provides an improved arrangement for replaceably supporting the lower annular course of brick adjacent the spout opening. The arrangement in brief including a detachable flange for mounting between radially outwardly directed flanges of the vessel and the spout, the detachable flange extending radially inwardly of the vessel flange and supporting the stepped lower annular brick course thereon. The invention in addition includes a method of replacing the lower annular brick course when relining the spout. The method includes the steps of the removing the detachable flange and the worn brick course, building a course of new brick on the detached flange, circumferentially securing the new course with a steel strap, and placing the detachable flange and new brick course as a unit between the flanges of the vessel and the re lined spout. With this method, the bricks may be accurately and safely mounted within a relatively short time. By using an additional detachable flange, an annular replacement course of brick can be prepared while the vessel is still in service and only a short interruption of the use of the vessel is required to renew the vessel opening lining.

In view of the above, it is a primary object of the present invention to provide an arrangement in steel degassing vessels having a downwardly depending detachable spout for removably supporting the annular course of refractory bricks located adjacent the spout.

It is a further object of the invention to provide an arrangement as described of a simple design which may be economically manufactured.

Afurther object of the invention is to provide a method of replacing the annular brick course adjacent the spout of such a vessel in an accurate, safe and expeditious manner.

Still another object of the invention is to provide an arrangement and method as described which permit the assembly of a replacement brick course prior to the interruption of service of the vessel.

Additional objects and advantages of the invention will be'more readily apparent from the following detailed description of an embodiment thereof when taken together with the accompanying drawings in which:

FIG. 1 is a partial sectional elevational view taken through the bottom of a conventional steel degassing vessel at the spout and showing the prior art arrangement for securing the annular brick courses adjacent the spout;

FIG. 2 is a partial sectional elevational. view of a steel degassing vessel embodying the improvement of the present invention;

FIG. 3 is an exploded sectional view similar to that of FIG. 2 showing the method of replacing the annular brick course adjacent the spout in accordance with the present invention;

FIG. 4 is a view partly in section taken along line 44 of FIG. 2; and

FIG. 5 is a partial plan view taken along line 5-5 of FIG. 3 and showing the detachable flange 'with a replacement course of brick assembled thereon.

Referring to the drawings, FIG. 1 shows the lower portion 10 of a conventional type of steel-degassing vessel having a detachable spout 12 downwardly depending therefrom. The metal vessel 10 slopes downwardly to an annular neck portion 14 which terminates in a flange 16, the flange having a radially outwardly extending portion 18 and a radially inwardly extending portion 20. The flange 16 provides a means for mounting the cylindrical spout 12 to the bottom of the vessel 10, the spout having a radially outwardly extending flange 22 which is secured against the vessel flange 16 by means of bolts 24. The bolts 24 are secured in a well known manner by means of wedges 26. The spout 12 is lined on the interior with refractory bricks 28 and on the exterior by a refractory tamping mixture 30.

The refractory bricks 28 lining the spout 12 form a cylindrical spout duct 32 which communicates upwardly with an inlet passage 34 formed in a refractory lining in the bottom of the vessel 10. The inlet opening 34 flares upwardly in a conical shape and is defined by the inner surfaces of wedge shaped refractory bricks which are usually disposed in two superimposed annular courses 3'6 and 38 and are radially outwardly succeeded by a refractory lining of similar depth formed of a plurality of suitably shaped bricks.

The bricks 42 of the lower annular course 36 are stepped at 44 to accommodate the inner portion of the vessel flange 16, the bricks being supported by the flange and abutting the upper row of lining bricks 28 of the spout 12. The bricks 42 radially adjoin the bottom covering bricks 46 of the vessel. The bricks 48 of the upper annular course 38 are supported in part by the first row of bottom covering bricks 46- and in part by the bricks 42 of the lower annular course 36. The bricks 48 are adjoined by further annular courses of bricks '50 resting on the bottom covering bricks 46.

The bricks 28 which line the spout 12 are exposed to the flowing hot steel and thus are subjected to more rapid wear than the refractory bricks disposed in other portions of the degassing vessel. As a result, the spout must be exchanged at least once and often several times during the life of one lining of the degassing vessel. In addition, the

bricks

42 and 48 of the

annular courses

36 and 38 are subjected to relatively high wear in comparison to the other bricks of the lining due to the flow of the steel therethrough. Experience has proven that the bricks 42 of the lower course 36 wear much more rapidly than the bricks 48 of the upper annular course 38, thus necessitating the replacement of the bricks 42, in most cases during the second exchange of the spout.

As indicated above, the bricks 42 of the lower annular course 36 must be replaced at elevated temperatures. During this operation, the new bricks must be radially inserted between the flange portion 20 of the vessel flange and the bricks 48 of the upper annular course. This would be a complicated task even if the vessel were cold and is particularly diflicult with a hot vessel, making the replacement relatively time consuming. The replacement is rendered even more difficult by the fact that the bricks of an annular course are necessarily wedge-shaped and the last brick of the course cannot be inserted radially from the inside but can be inserted only in an axial direction, in the present case from below. For this purpose, a corresponding opening for the insertion of the last brick must be formed in the vessel flange 16 so that this flange is greatly weakened. During this operation, only part of the underside of the bricks of the lower annular course and the conical inside of such bricks are visible, so that it is not possible to check whether the bricks have been placed with properly closed joints and have been properly bonded to the adjacent bricks of the lining.

The arrangement of the present invention is shown in FIGS. 2-5 wherein a degassing vessel 10' having the same shape and brick lining as that described above in FIG. 1 is illustrated. The vessel itself differs only in the respect that the end flange 1' extends only radially outwardly from the neck 14'. A detachable flange 60 is adapted to seat against the flange 16' and includes a radially inwardly directed portion 62 upon which the bricks 42 of the lower annular course 36 are supported. The

flange 60 is stepped at 64 with the inwardly extending portion 62 fitting upwardly within the neck 14' of the vessel so that the flange 16' with the detachable flange 60 mountedthereon comprises essentially the same sectional shape as the flange 16 of the prior art vessel. The flange 60 is attached to the flange 16 by the countersunk bolts 66 and wedges 68, the bolts passing through aligned holes in the vessel flange and detachable flange.

This arrangement permits the employment of refractory bricks of the same arrangement and sizes as employed in the FIG. 1 prior art vessel. The arrangement further permits the use of a conventional spout 12 which is mounted against the underside of the detachable flange 60 and secured thereagainst by bolts 24 and wedges 26, the bolts passing through aligned holes in the spout flange 22, detachable flange 60 and vessel flange 16.

For the initial installation of the lining, the detachable flange60 is secured to the vessel flange 16' by means of bolts 66 and the lower annular course 36 of bricks 42 is laid with the step 44 of the bricks resting on the inwardly extending portion 62 of the flange. The bottom covering bricks 46, bricks 48 of the upper course 38, and the bricks are then laid successively in the same manner as that employed with the prior art vessel design. When the vessel has been completely lined, the lined spout 12 is engaged with the detachable flange from below and is secured to the vessel by means of the bolts 24 in a conventional manner.

When the bricks 42 of the lower annular course 36 are to be replaced by new bricks, the replacement can be carried out quickly and safely with the present arrangement while the vessel is at an elevated temperature. When the spout 12 has been removed from the vessel, the detachable flange 60 is also removed from the vessel so that the new brick course can be made up on the detached flange without the handicap of heat or lack of space. The new course of bricks must of course be carefully arranged on the flange so as to fit accurately with respect to the remaining lining of the vessel. For this purpose, it is preferred that the new brick be secured by a steel strap 70 following alignment of the flange. The strap holds the bricks in the desired alignment and permits a rapid replacement of the brick course and flange as a unit.

In view of the fact that the wear of the

original bricks

42 and 48 results in an increase in the size of the conical inlet opening 34 as illustrated at 34 in FIG. 2, replacement bricks 42' having an inside surface dimension and design to match the wear of the bricks 48 of the original lining should be employed. The view of FIG. 2 shows a vessel of the present type following a replacement of the brick 42 with the replacement bricks 42' which provide a smooth continuation of the inlet opening in the upper annular course 38.

The method of replacing the lower annular course 36 is illustrated in the exploded view of FIG. 3. Following removal of the spout and the detachable flange 60, the old course 36 is removed. A new course 36 made of brick 42' is built directly on the detachable flange 60 and secured by the steel strap 70 in the proper alignment. The flange and new course 36 are then raised as a unit against the vessel flange 16 and secured thereto by bolts 66. The spout 12 is then positioned against the detachable flange and secured by bolts 24 in the conventional manner.

It is obvious that in the present process the replacement bricks 42' can be positioned on the detachable flange with a much higher accuracy then in a process in which the bricks are inserted between the end flange and the bricks of the upper annular course of the hot degassing vessel. With the replacement bricks 42 dimensioned to match the wear of the bricks 48 of the upper course 38, the formation of a step between the adjoining annular courses is avoided. Such a step could give rise to turbulence in the flowing steel with a resulting more rapid destruction of the bricks at that point.

The down time required for replacement of the spout and lower annular brick course can be greatly reduced if at least one extra detachable flange provided with replacement bricks 42' is prepared in advance, and a completely lined spout also made available in advance. Interruption of the operation of the degassing vessel is then required only for the short time necessary to remove the spout and detachable flange and to attach the prepared flange with its brick course and the relined replacement spout.

Because of the very high accuracy with which the replacement "brick course can be formed on the detached flange at a point remote from the hot degassing vessel, the life of the replaced brick course is substantially increased permitting longer periods of use between replacement.

Manifestly, changes in details of construction can be effected by those skilled in the art without departing from the spirit and the scope of the invention as defined in and limited solely by the appended claims.

We claim:

1. In a refractory lined steel degassing vessel having an annular opening in the bottom thereof and a flanged neck portion extending downwardly from said opening adapted for the demountable connection of a downwardly depending flanged spout thereto, said spout having a cylindrical spout duct extending downwardly from said opening and a spout flange arranged on its upper end, the improvement comprising a detachable annular flange between the flanged neck portion of the vessel and the flanged spout, said detachable flange having a radially inwardly extending portion adapted for supporting an annular course of refractory brick adjacent the spout, and means for securing said detachable flange and said spout flange to the flanged neck portion.

2. A steel degassing vessel having a refractory brick lining, the bottom of said vessel having a conically upwardly flaring inlet opening therein for the passage of molten steel into the vessel, said vessel having a downwardly extending neck portion at said opening, said neck portion having a radially outwardly directed flange at the lower end thereof, a detachable flange mounted beneath said flanged neck portion and extending radially interiorly thereof, means for demountably securing said detachable flange to the flanged neck portion of the vessel, a refractory brick lining in said opening including an annular course of refractory brick supported on the inwardly extending portion of said detachable flange, a demountable flanged cylindrical spout downwardly depending from said vessel and having a cylindrical spout duct extending downwardly from said inlet opening and axially aligned therewith, and means for demountably securing said spout to the vessel beneath said detachable flange.

3. A vessel as claimed in claim 2 including a refractory brick lining in said spout forming said spout duct, the refractory brick of said annular course being stepped to accommodate the detachable flange and contacting with their lower surfaces the lining bricks of the spout.

References Cited UNITED STATES PATENTS 1,169,653 1/1916 King 164-337 3,353,809 11/l967 Snellman 266-38 X 3,354,939 11/1967 Calderon 164-337 X I. SPENCER OVERHOLSER, Primary Examiner J. S. BROWN, Assistant Examiner