US3043470A

US3043470A - Refractory-lined vessel

Info

Publication number: US3043470A
Application number: US55442A
Authority: US
Inventors: Puxkandl Peter
Original assignee: Voestalpine AG
Current assignee: Voestalpine AG; Voest AG
Priority date: 1959-10-08
Filing date: 1960-09-12
Publication date: 1962-07-10
Anticipated expiration: 1979-07-10

Description

July 10, 1962 P. PUXKANDL 3,043,470

REFRACTORY-LINED VESSEL Filed Sept. 12, 1960 2 Sheets-Sheet 1 FIG. 7

a INVENTOR. PETER PUXKANDL BY mam w H IS ATTOR N EYS July 10, 1962 P. PUXKANDL REFRACTORY-LINED VESSEL 2 Sheets-Sheet 2 Filed Sept. 12, 1960 INVENT0R.-1 PETER PUXKANDL.

H IS ATTORN EYS United rates The ironand steel-making industries use refractorylined vessels which comprise a cylindrical shell, which carries at one or both ends an annular flange, to which a cover or bottom part, which is in most cases domeshaped, is secured with screws.

Such vessels are, e.g., mixers for crude iron and converters. Mixers for crude iron have the purpose of collecting the iron coming from the blast furnace before it is processed further and to make it more uniform in quality. A mixer for crude iron, which consists of a cylindrical shell and two covers attached with a screwed flange joint to both ends of the shell, is arranged in a horizontal position. It is rotatable about an axis which is parallel to its longitudinal axis. In order to protect the wall of the vessel from the attack of the liquid crude iron and to minimize the heat losses, a lining is provided as is usual in industrial furnaces. Before putting the mixer into operation by charging it, the lining is heated with gas burners to the operating temperature to be expected, e.g., to about 1200 to 1300 C. This causes the heated bricks to expand more than the surrounding shell of sheet metal.

In the known screwed joint between the cover and bottom parts and the annular flanges of the vessel, the screws have only such a size that they will break in any case before a breakage of any other portion of the shell in order to prevent a formation of cracks owing to the thermal expansion of the bricks. The annular flanges have been attached to the shell either with their inner end, i.e., in L-shape, or with their central portion, i.e., in T-shape. The first method has the disadvantage that the flange will bend under the influence of the eccentrically acting screw forces so that bending stresses in addition to tensile forces are introduced into the vessel. The second method has the disadvantage that the thrust of the expanding brick structure acts on the inner part of the flange before it reaches the cover so that breakage of the flange will result while the screws are not loaded.

It is an object of the present invention to avoid the described disadvantages by the provision of a joint between the cylindrical shell and the bottom part or the cover whereby a cracking of the sheet metal parts adjacent to the flanges due to expansion stresses is reliably avoided. The invention resides in that the shell portion which carries the annular flange is of conical shape in respect of a decrease of thediameter of the vessel and the inclination towards the axis of the vessel is preferably such that the resultant of the forces taken up by the flange lies in the system line of the cylindrical shell. The design of the shell part according to the invention causes part of the longitudinal thrsut forces of the bricks to be converted into peripheral forces, which do no longer load the cover, the screwed joints and the flange.

The invention is explained more fully in the drawing. FIGS. 1 and 2 show screwed flange joints of known type. FIG. 3 shows a mixerfor crude iron according to the invention in a vertical longitudinal sectional view. FIG. 4 is an enlarged View showing the joint according to the invention.

In the known joint shown in FIG. 1 between a cover ate m M 3,043,470 Egfi Patented July 10, i962 and a cylindrical shell, the annular flange 2 is joined at its inside edge to the shell 1, e.g., by welding, so that an L-shaped cross-section is obtained. The flange has one or more series of screw holes 3. The cover 4 is placed on the flange and connected with screws. The resultant of the forces taken up by the flanges lies in this case before the system line A of the cylindrical shell 1. This gives rise to undesired bending stresses.

FIG. 2 is a similar showing of a known joint, in which the middle portion of the flange 2 is joined to the shell 1 so that a T-shaped cross-section is obtained. Whereas the resultant of the forces taken up by the flange does lie in this case in the system line A of the cylindrical shell, an expansion of the brick lining 5 in the longitudinal direction of the vessel will cause pressure to be exerted on the inwardly protruding portion 2' of the flange so that this portion breaks whereas the screws have not been loaded at all.

FIG. 3 shows a mixer for crude iron according to the invention. The end portions 6, 6' of the shell 1 are conical and the annular flanges 2 are joined at their inside edge to the

portions

6, 6. This results in an acuteangled section (half Z-section) (FIG. 4). The flanges 2 are formed with two series of screw holes 3. The cover 4 is secured with screws to the flange. It is apparent that the inclination of the portions 6, 6' toward the axis 7 of the mixer is such that the resultant of the forces taken up by the flanges 2 lies in the system line A of the cylindrical shell.

After a break-age of the screws the same are easily accessible and can be readily replaced. The thrust forces of the brick lining 5 undergoing thermal expansion are partly converted in the

conical portions

6, 6" into peripheral forces, which do not load the annular flanges 2. The expansion forces acting on the cover are transmitted to the screws. Under high stresses the screws may break whereas a rupture of the flanges, the cover or the cylindrical shell will be reliably avoided. The flanges cannot introduce bending forces into the vessel, particularly if they are supported with ribs 8 against the

conical portions

6, 6 in a preferred embodiment (FIG. 4).

What I claim is:

1. A refractory-lined vessel comprising a cylindrical shell carrying at each end an annular flange, a cover part being secured to the annular flange characterized in that a shell portion adjacent to each end of said shell and carrying the flange is of conical shape in respect to a decrease of the diameter of the shell.

2. A vessel according to claim 1 in which each flange has two series of screw holes the centre line of which lies in the system line of the cylindrical shell.

3. A refractory lined vessel according to claim 1 in which the inclination of the conical shape is such that it forms an acute angle with the flange.

4. A vessel comprising a cylindrical shell carrying at each end an annular flange to one of which a bottom part and to the other of which a cover part is secured with screws, the cylindrical shell and the cover and bottom parts being lined with refractory bricks, the shell portions carrying the flanges being of conical shape in respect to a decrease of the diameter of the shell and the inclination of these conical portions being of such an amount that the resultant of the forces taken up by the flanges lie in the system line of the cylindrical shape.

5. A refractory-lined vessel for treating molten iron comprising a cylindrical shell carrying at each end an annular flange to one of which a bottom part and to the other of which a cover part is secured with screws, the shell portions carrying the flanges being of conical shape 3,043,470 3 in respect to a decrease of the diameter of the shell and References Cited in the file of this patent the inclination of these conical portions being of such an amount that the resultant of the forces taken up by UNITED STATES PATENTS the flanges lie in the system line of the cylindrical shape 87,231 Yates Feb- 23, 1869 each flange being supported with ribs against the conical 5 2,392,267 salkpver 1946 portion of the vessel adjacent to it. 2, 29, 77 D vlS Apr. 8, 1958