US2436452A

US2436452A - Water-cooled furnace supporting member

Info

Publication number: US2436452A
Application number: US488580A
Authority: US
Inventors: William E Schmidt
Original assignee: Individual
Current assignee: Individual
Priority date: 1943-05-26
Filing date: 1943-05-26
Publication date: 1948-02-24
Anticipated expiration: 1965-02-24

Description

Feb. 24; 1948;

w. 'E. SCHMIDT WAT ER-COOLED FURNACE SUPPORTING MEMBER Filed May gs, 1943 s Shets-Sheet 1 mmvron: mLLM/V E5CHM/D7;

Feb. 24, 1948.

W. E. SCHMIDT WATER-COOLED FURNACE SUPPORTING MEMBER 3 Sheets-sheaf. 2

Filqd May 26, 1945 INVENTQR.

MIL/AM E. 50/17/07;

, fro/nay.

Feb. 24, 1948. w. E. SCHMIDT WATER-CQOLJED FURRACE SUPPORTING MEMBER Filed May' 26 1943 3 Sheets-Sheet 3 IIIIIIIIIIIIIIIIIIIIIIIII'IIII'III ///M/ m m y 1 ,o fl// p E A 0 mm M M 'tice is to use bare 2,436,452 I WATER-COOLER) FURNACE SUPPORTING MEMBER William E. Schmidt, Chicago, Ill. Application May 2.6, 1943, Serial No.4ss,sso-- 21 Claims. ((31. 263-6) This invention relates to an improved watercooled furnace supporting member. When watercooled supporting members are used in the combustion chamber of a furnace, the present pracpipe as the supporting member. The bare water-cooled supports are surrounded by cold zones which chill the gases in the combustion chamber, thus causing poor flame propagation. If the support carries metal to be heated, the cold zone surrounding the pipe prevents the flame from reaching the underside of the metal and also extracts heat from the underside thereof. The cooling water in the pipes absorbs and carries ofl a great deal of heat from the metal. This heat loss occurs in the zone surrounding the point where the metal rests on the support and must practically all be replaced by conduction within the body of the steel. Since this heat must be conducted from the top surface of the steel where the heat is absorbed from the flame and is very much lower than the rate of heat absorption, there is a cold spot in the metal at the point of. its support.

It is an object of this invention to provide a water-cooled furnace supporting member in 4 which the cold zones are practically eliminated.

This and other objects will be more apparent after referring to the following description and attached drawings in which:

Fig. 1 is a. view showing the heat flow in a heating furnace having a bare water-cooled pipe therein;

Fig. 2 is a viewsimilar to Fig. 1, but showing a covering around the pipe;

Fig. 3 is a view showing the heat flow about the bare water-cooled support of a continuous heating furnace;

Fig. 4 is an end view showing the heat flow about thesupport of Fig. 8;

Fig. 5 is a view similar to Fig. 3, but showing 7 a covering around the pipe;

Fig. 6 is a view similar to Fig. 4, but showinga covering around the pipe;

Fig. 7 is a. plan view of a covering;

Fig. 8 is a sectional view on line VIIIVIII of Fig.

Figs. 9 and 10 are view ing further modifications:

Figs. 11 and 12 are sectional views showing modified forms of the skid pipe barrier of Fig. 5;

Fig. 13 is a vertical section showing the barrier applied to a vertical water-cooled pipe;

Fig.3 1c is a sectional view on line XIV-4m! of modified form of pipe similar to Fig. 8 show- Referring more particularly to the drawings. Fig. 1 shows the heat flow in a heating furnace having a bare water-cooled pipe. In the furnace flames 2 are applied both above and below the metal 5. Below the metal is a pipe ii containing cooling water 8 which interferes with the uniform heating of the metal i. The small arrows indicate heat flow from the flame by convection and radiation to the surface of the metal i and thence into the mass of metal by conduction. The heat from the flame 2 flows in the direction of the coldest object which in this case is the pipe 6. Heat also flows from the hot metal Al to the cold pipe 6 at a faster rate than it can be conducted through the metal from the top surface, This condition causes the cooling of the metal surface and creates a cold spot ill which penetrates to considerable depth. When a state of equilibrium is reached, there is a more or less definite line of demarcation which is indicated'as a line of heat equilibrium i 2.

Fig. 2 shows how this condition is corrected by surrounding the pipe 6 with a refractory barrier it which acts as a barrier between the hot flames 2 on one side and the water-cooled pipe 6 on the other, thus slowing down the rate of heat transfer from the flame 2 to the water-cooled pipe 8 to such an extent that the line of heat equilibrium i2 is established somewhere, in the body of the refractory it. Under these conditions the flame side of the refractory becomes luminous and refiects back part of the heat while the water 3 r; absorbs enough heat from the refractori to protect it from overheating. The small arrows indicate heat flow in the furnace and it is clear that there is a much improved condition of heat application with practically uniform heat conduction from the top and bottom surfaces of the metal.

Figs. 3 and 4 show the heat flow about the bare water-cooled support of a continuous heating furnace. The billets to be heated pass from the charging end to the delivery end of the furnace in a continuous stream. The burners are located at the delivery endand flames pass over the topand beneath the billets. The supporting means for the billets in the furnace are of three types, each extending about one-third the lengthof the furnace. The supporting means on the charging end of the furnace-consists of two bridge walls having skid pipes embedded therein for supporting the billets. The supporting means of the middle third consists of a wearing strip I6 mounted on a watercooled skid pipe i8. Skid pipes are supported above the bottom combustion chamber on several pipe cross beams 20 which are also water-cooled.

' the billet 22.

' cooled pip from the The cold zone 24, the wearing strip l6 and the skid pipe l8 combine to cause a cold spot 26 in The water-cooled support pipe 20 creates a cold zone spot 30 in the billet. The

cold spots

28 and 30 must be soaked out during the period in which the steel passes over the hearth. The soaking heat comes from the top combustion chamber and must pass entirely through the steel by conduction. Since there is not sufficient time to completely soak out the cold spots during the passage of the steel over the hearth of the soaking zone, there is a temperature differential in the mass of steel when it reaches the rolling mill. Rolling stresses vary with the temperature and variation in stresses will cause rupture of the steel, breakage of rolls. spindles, etc.. and increase the power requirements. The

steel. For example, a temperature differential of 100 F. around rolling temperature means the difference of 1,000 pounds per square inch in tensile strength of a .30 carbon steel. With-a differential of 300 F. the strength difference is 2,800 pounds per square inch.

Figs. and 6 show how the cold spots are greatly reduced by using a refractory barrier. By covering the skid pipe and skid pipe support with a refractory tile or barrier the cold zones 24 and 28 will be eliminated, thus eliminating cold spots 30 and reducing the cold spot 26 to that caused by the wearing strip It. By eliminating the cold zones 2!. and 28 there will be no screening effect between the flame and the bottom surface of the steel to' prevent-heat transfer. This improves the heating efliciency of the bottom combustion chamber and permits a maximum heat application to the bottom side of the billet as it moves into the hearth. In addition to increasing the efliciency of the flame and reducing the cold spots in the metal being heated, the use of the refractory barrier decreases the heat loss to the cooling water, thus reducing the amount of cooling water required. The size of the supporting member can be decreased without sacrificin strength. The refractory also protects the waterscouring effect of the flame. especiallywhen fuel-oil is used. Substantial fuel savings results from the improved combustion and the reduction in heat losses.

The barrier is made of any suitable refractory material. It is desirable to use a refractory having good insulating qualities, but it is not always possible to use such refractories since they commonly lack the structural strength which may be necessary. The barrier preferablyis made in sections for ease of installation. Many different forms may be used. The barrier shown in Fig. 2 is made in half sections each section having a lug 82 on the upper half thereof. Welded to the pipe 5 are two lugs 34. The lugs 32 are supported on the lugs 34 and since the center of gravity of each section is outside the supporting surface of lug M, the two sections swing together with the bottom lugs 38 in contact. The

lugs

32 and 30 also 28 which in turn causes a cold difference in temperature need not be great to cause a substantial difference in the strength of the provide a dead air space 01 therebetween. This dead air space acts as additional insulation and is of special value-when'the refractory has poor insulating qualities. If desired, space 31 may be filled with a good insulator. The adjoining edges of the two sections are serrated or roughened to provide a good bond when fastened together with high temperature cement.

Fig. 6 discloses a type of tile which is quite similar to that shown in Fig. 2. Instead of having a bar lug welded to the pipe, pipe nipples 38 are welded thereto and the tile has lugs 40 which fit therein. Otherwise tiles are the same.

- Fig. '1 is a plan view of a somewhat different type of tile, the top edges being formed with interlocking dove-tails 42. A single row of pipe nipples M is welded to the top of the watercooled pipe and lugs 46 on each half section of tile engage alternate nipples 44.

The modification of Fig. 9 diflers from that of Figs. 7 and 8 in that a single row of solid lugs 48 are welded to the top of the water-cooled pipe and alternate lugs 18 fit into openings 50 in each half section of tile.

The embodiment of Fig. 10 is like that of Fig. 9, except that the holes in the tile have bottoms 52 in order' to space the tile more uniformly from the pipe.

Fig. 5 discloses a tiiewhich surrounds the water-cooled skid pipe. This differs from the barrier shown in Fig. 2 in that the two half sections are cut away at the top and are bonded together only at the bottom. i

Fig. 11 discloses a second modification of a tile for the skid pipe. An L-shaped lug Bl is welded to each side of the pipe at its horizontal diameter. A corresponding L-shaped lug 56 on the tile engages lug i4 and the top'portion of the tile is straight as shown at $8.

The tile of Fig. 12 has openings 60 in each half thereof which fit over lugs 82 welded to the upper part of the water-cooled skid pipe. Bottom lugs 63 have serrated edges and are bonded together withhigh temperature cement. It will be understood that the bottom lugs may be omitted and that reinforcing ribs maybeformed on the inside of the tile to give additional strength.

Figs. 13 and 14 disclose the invention as applied to vertical lintel piping. Water passes down through pipe 84 and back up through pipe 68 to be discharged into a drain (not shown). These pipes are slightly spaced from the refractory 10 of the furnace wall. welded to the pipe 66 are four lugs 12. Surrounding the pipe is a two part refractory barrier 10 which may be made from a good insulating material. Each half section of tile has a flat portion 10 which is. aced slightly from the wall 10. A counterbore I in each half of the tile forms an air space between the tile and pipe 86 and also in combination with lugs 12 prevents the tile from rotating on the pipe.

While several embodiments of. the invention have been shown and described, it will be -appar- 7 function to space the barrier from the pipe to ent to one skilled in the art that other adaptations and modifications may be made without departing from the scope of the attached claims.

I claim:

1. An improved water-cooled furnace supporting member comprising a barrier surrounding said water-cooled member, said barrier being spaced from said member a substantial distance throughout the majority of the periphery of said member to provide a dead air space therebetween.

improved water-cooled furnace support-- said water-cooled member,

of lugs on the upper half fastened to the upper part of said ing member comprising a refractory barrier surrounding said water-cooled member, and a, good insulating material between said member and said barrier.

3. An improved water-cooled furnace supporting member comprising a barrier surrounding said water-cooled member and spacing lugs on said barrier for spacing said barrier from said member to provide an air space therebetween.

4. An improved water-cooled furnace supporting member comprising a. barrier surrounding spacing lugs on said barrier for spacing said barrier from said member to provide an air space therebetween and lugs on said member for engaging at least one of said lugs on said barrier for supporting said barrier.

5. A substantially horizontal water-cooled furnace supporting member comprising a plurality of lugs on the upper half of said member, a two part refractory barrier suspended from said lugs and surrounding said member and at least one lug on each half of said barrier being in engagement with one of said first named lugs, the center of gravity of each half of said barrier being outside the point of suspension.

6. A substantially horizontal water-cooled furnace supporting member comprising a plurality of lugs on the upper half of said member, a two part refractory barrier suspended from said lugs and surrounding said member and top and bottom lugs on each half of said barrier for spacing said barrier from said member, said barrier being suspended from said first named lugs by means of said top lugs, the center Of gravity of each half of said barrier being outside the point of suspension.

7. A substantially horizontal water-cooled furnace supporting member comprising a plurality of lugs on the upper half of said member, a two part refractory barrier suspended from said lugs and surrounding said member an top and b ttom lugs on each half of said barrier for spacing said barrier from said member. said barrier being suspended from said first named lugs by means of said top lugs, the center of gravity of each half of said barrier being outside the point of suspension and the adjoining edges of said sections being serrated to provide for better bond therebetween. r

8. A substantially horizontal water-cooled furnace supporting member comprising a plurality of said member, a two part refractory barrier suspended from said lugs and surrounding said member, top and bottom lugs on each half of said barrier for spacing said barrier from said member, said barrier being suspended from said first named lugs by means of said top lugs, the center of gravity of each half of said barrier being outside the point of suspension, the sections of said barrier being held together by a dove-tailed seam at the top thereof and the adjoining edges of said sections being serrated to provide for better bond therebetween.

9. A substantially horizontal water-cooled supporting member comprising a plurality of lugs member, a refractory barrier surrounding said member, said barrier being divided into two sections, the upperedges of each of said sections having dovetails therein to form an interlocking joint, and means on each of said sections engaging at least one of said lugs for support thereon, the center of gravity of each of said sections being outside the point of suspension.

' with limited 10. An improved water-cooled furnace supporting member comprising a barrier surrounding said water-cooled member and means for spacing said barrier from said member a substantial' distance throughout the majority of the periphery of said-member to provide an air space therebetween.

11. Work-supporting structure comprising a work-supporting member having a work-engag ing portion and preformed protective means disposed generally about and supported entirely by the work-supporting member to protect the same but with the work-engaging portion exposed to engage work supported by said structure.

12. Work-supporting structure comprising a work-supporting member having a protruding work-engaging portion and preformed protective means carried entirely by the work-supporting member and protecting the same but with the work-engaging portion protruding to engage work supported by said structure.

13. Work-supporting structure comprising a work-supporting member having a work-engaging portion and having a cooling fluid passage therein and preformed protective means disposed generally about and supported entirely by the work-supporting member to protect the same but with the work-engaging portion exposed to engage work supported by said structure.

14. Work-supporting structure comprising an elongated work-supporting member disposed to support work resting thereon and having a longitudinally extending work-engaging portion at its upper part and preformed protective means disposed generally about and supported entirely by the work-supporting member to protect the same but with the work-engaging portion exposed to engage work supported by said structure.

15. Work-supporting structure comprising an elongated work-supporting member having a work-engaging portion and preformed protective means applicable laterally to the work-supporting member as distinguished from having to be applied endwise thereof and protecting the worksupporting member but with the work-engaging portion exposed to engage work supported by said structure.

16. Work-supporting structure comprising a work-supporting member having a work-engaging portion and preformed protective means disposed generally about the work-supporting member to protect the same but with the work-engaging portion exposed to engage work supported by said structure, the protective means being carried entirely and loosely by the work-supporting member and being free to shift relatively thereto.

17. Work-supporting structure comprising an elongated work-supporting member disposed to support work resting thereon and having a. longitudinally extending work-engaging portion at its upper part and preformed protective means disposed generally about the work-supporting member to protect the same but with the work-engaging portion exposed to engage work supported by said structure, the protective means substantially surrounding the work-supporting member except for the work-engaging portion and being carried by the work-supporting member by engagement surface portions thereof at opposite sides of the work-engaging portion.

18. Work-supporting structure comprising an elongated work-supporting member disposed to support work resting thereon and having a longitudinally extending work-engaging portion at its upper part and protective means assuming generally the form of a split ring surrounding the major portion of the work-supporting member and supported entirely thereby but with the work-engaging portion exposed through the split therein to engage work supported by said structure.

19. Work-supporting structure comprising an elongated work-supporting member disposed to support work resting thereon and having a longitudinally extending work-engaging portion at its upper part and protective means assuming generally the form of a split ring surrounding the major portion of the work-supporting member but with the work-engaging portion exposed through the split therein to engage work supported by said structure, the cross-sectional area of the space within the protective means being substantially greater than the outside crosssectional area of the portion of,the work-supporting member about which the protective means is disposed.

20. Protective means comprising a plurality of cooperating members adapted to be applied by 2 Number lateral movement to an elongated work support or the like to form a self-contained hollow pro-' tectzve member disposed generally about the suppor v 21. Protective means comprising preformed shapes adapted to be assembled to form a hollow split protective member adapted to hang on a work support with a portion of the work support exposed through the split therein, the inner surface of the protective member having generally inwardly projecting portions at opposite sides of the split.

WILLIAM E. SCHMIDT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Van Zile Oct. 28, 1902 Harrington July 4, 1911 Corriston Dec. 3, 1935