US1771306A - Flue structure for regenerative stoves - Google Patents

Description

` 2 sheets-sheet 1 July 22, 1930. A. c. NELSON FLUE STRUCTURE FOR REGENERATIVE STOVS Filed Aug. 1o, 1928 July 22, 1930.

A. c. NELSON FLUE STRUCTURE FOR REGENERATIVE STOVES 2 Sheets-Sheet 2 Filed Aug. 10, 1928 6' Naso/v Arme/VHS AU'e-o P| 9 WM www lm 50 Among the objects of Patented y July 22, 1930 UNITEDSTATES vALFRED c. Nansen, or 'Lnrrrzvvoon OHIO `FLUE STRUCTURE FOR nEGnivEnATivE S'rlovEs f Application led VAugust 10, 19283. Serial 110,298,790. y

My invention relatesto the type of regenerative heatjeXchange apparatus of which blast furnace hot blast Vstoves and openhearth furnace regenerators are common y forms.. In'apparatus of this type gases are burned and passed over or throu h some refractory material, such `as fire brick. A Zhen this refractory material is suiliciently heated the flow of hot gas is shut off and cool airis 10 forced `through inthe opposite direction. Ihe air is heatedby contact as it passes by the hot refractory `material and continues to flow until a certain amount of the heat left in the refractory material vbythe hot gases is ab isorbed. `The cycle `is then repeated,`the hot gases heating the refractory material and e the cool air absorbing the heat, the refractory material being alternately heated by the hot gases and cooled by the air or gas whose temperaturefis to be increased.

In this specification and in the drawings I have shown and described my invention as applied toa common form of'hot blast stove nsedin connection with blast furnaces for reducing iron ore to iron.v In this type of `stove the gases from the top of the blast furnace are conducted to the stove where they are'burne d,the Vhot burning gases passing by the refractory brick for a certain length of Sotime. The gaskis then shut off and air is forced through the heated checker-work of brick andrinto the blast furnace, furnishing the heated airrequired for the reduction of the ore. In this way the gas` resulting from the operation of the blast furnace is utilized to pre-heat the air'. 'Several separate hotblast stoves are used` inxconnection with one blast furnace so that while one is furnishing heated air to thefurnace the Others are being 40 heated by'burning waste gas from thef blast furnace in `the combustion chamber ofthe stove. In' thisway a continuous supply'of pre-heatedair is obtained. In case ofan open hearth' regenerator the waste heat Vfrom the furnace heats the regenerators directly (the open hearth furnace vitself acting as a comv bustion chamber for-the waste gases) and the e reversals occurmorefrequently than ine-blast furnace practice.

i tically.' adjacent courses of brick separatedto my invention are :f

The *provision of an improved method `of laying up brick for `the flue structure Of re-` generative stoves by` virtue of which 'each brick in the flue structurecan expand without disturbing its neighbor; the provision of alflue structure made of rectangular brickin which the individual flueshave a much greater surface area in proportion to theircrosssection area thanV other forms which have been heretofore proposed the provision of a checkerwork structure made `of `rectangular Y Y brick whichmay be easily and quickl laid upand in which all joints betweenbric s are bonded by the bricks in the'adjacent courses; the provision ofl a checker-brick structure in which there is no Waste' or inactive brick. the brick being'so laid that the walls between all the nues are of uniform thickness, and the provisionV of a flue structure having flues a cross-shaped on a plane erpendicular to their longitudinal axes. ther advantages of my invention over other types ofiue struc` tures will be evident from the drawings and specification. e

I do not limit my invention to the specific form shown in this specification as it -willbe clear to those skilled in the art that it may be adapted to other types of regenerative heat exchange apparatus and embodiedin structures other than that shown.`

Referringto the drawings y f,

Fig. 1 is a vertical section through acommon type of hot blast stove, the lues of which are built in accordance with my invention.

Fig." 2 isan enlarged view taken'between lines 2A, 2A and 2B, 2B in Figi `1,sh"o\` ving stove shownin Fig. 1.

Fig. 3 is a plan sectionl ofmyimproved stove taken on line 3 3 of Figs. 1 and 2.

Fig. Itis' an enlarged plan view ofia por- `several courses of brickofa portion of the ofbrick. il

` tion of the flue structure showing two courses Fig. 5 .is a perspective view of twover-V show how the bricks offene course Overlap those of theadjacent course. `f

The `hot blast stove shown in Fig." 1" is thetypeused in connection with `blast -furnaces. When thestove is in 'operation the blastfuxf nace gas enters the bottoni of the combustion chamber l through the pipe 2.V The gas burns in the chamber l and the dome 3 and passes down through the refractory brick iiues 4 and out the chimney 5. After the checkerbrick iue structure is sulhciently hea-ted the gas is shut ott and air is passed through the stove inthe opposite direction.` It ente-rs, at the bottoni and passes up through the heated flues 4, then dowli through the combustion` chamber l and out at the bottom of the com# bustion chamber. The stove has a steel shell 6 and a lining'7 of refractory material. vAs shown in Figs. Band 4the flues 4 made in accordance with my invention are vcrossshaped in horizont-al section.- gFlue structuies which have been built prior V"to my, invention havek been of square,frectangulai, or round shape iii-horizontal cross-section. Y

My invention provides Va methodfor laying up crossshaped flue structures from standard rectangular brick. As shown 'inFi`g. 3. two sizes of brickare used. Bricks` 9 may be considered to be 9X 3'. X4 and bricks yl0 to be 6 X BX 4-. `The bricks, of course,

` lower course appears on'rthc left and theA up-v pery course on ther right. On,` theright the lowercourse is shown under .the ,upper-course, in dotted lines. Aswill be 'seen from rthe drawings the lower course consists of ldouble rowsof 9 X 3 ,brick 9 laidparallel and l2 apart'. The bricks in. each single row of' these double rows are spaced aparte/admise... three inches and the three-incli-openings-are bridged by the bricks in the adj aeentgsingle row of spaced-apartY bricks. ABetween the Y' .s by .brick 1 il".

double rows of spacedfapart 95'` 3X 3:bricks 9 are laidA the 6, X8 bricks lO. These are placedwith their longitudinal ,aXesat 9,00 to the longitudinal yaXes of `the double rows of 9 X 3 bricks 9 and are staggered so that each Voverlapsfthe adjacent brick three inches. These' 6, Xl 3'( bricks l0 .form zig-zag rows between the spacedapartdouble. rowsv ofv Q X13brick egna-nd, asis elearlyshownfin Fig. 3,fcomplete the walls between the rcrossshapedflue-openings 4. '-,Th'ese cross-shaped due l(menings .4 .are all off'the ,same` size,- eachz of their angles vbeing 900 and each ofsltheir sidesfS bei-ng, three Vvinchesilo'ng. Y.. They are arranged -in diagonal -.i -ows and are so spaced apart'. that j the --center line` l-l, 1' Fig.. 4, of the bricks is always equidistantfromthesurface;v oft-,wo` adjacent nue ropienings. j 4.Thus if each flue-opening iSiconsidered toz be surrounded hck, tl1erexw11 be. eepartot the? refractory material which is so far from a flue surface that it is inefiicient in absorbing and giving off heat. This is an importaut advantage of my invention as the regenerator is much more eliicient when the bricks up in YeXactly the same way and of the saine size bricks as the course below. AHowever, inf

order that the joints between the bricks may be bondedrand each brick notl merely piled directly on top of the corresponding brick in the course below, the longitudinal double rows of 9 XfQbricks 9vare laid on top of the 6 X 3 bricks l0` of the course below and midway between the; double longitudinal rows of 9l X 8 bricks 9 ofthe course below. These double longitudinal rows of 9 X 3' bricks l() are laid .parallel in allthe courses. In this Vway the cross-shaped flue openings of the upper course correspond with those of the lower course` andeach joint in the lower course is coveredby a brick in the upper course.

Fig. 5 of the drawings shows two'adjacent courses of brick in perspective. The courses have been separated to show the individual bricks inoie clearly. The method of laying up the bricks so that each course is bonded by 1 the adjacent courses can be ,clearlyV seen.

, Several of' the bricks in the upper course have been `projecteddown to showV wherethey would be placed onv the lower course ii' the courses were not separated, for instance the Vbricks 9 wouldfcover the shaded area 9' and Vthebricks lOv-'ould cover the shaded area 'The entire flue structure of the stove is built upasabove described, as many courses y wouldnet provide a bond between4 the different courses. IThe.bonding which is very advantageous `in strengthening vthe. Aentire structure is obtained as 4above described*A and consists of merely".shifting thc'rposition of everywother.course..--.All the courses when 4 1 consideredy separately vare identical. y ,-My torni of .flueis superior toother forms. -itflias a much greater surface area ,of

in that j brick inproporti/on tothecrossesection area..

canbe shownbvassuming that the lues i s fownl Fig; Sottile .drawings are laid upv of bricksthree inches wide. y that v.each,ofthe .surfaces- Sjof the, fines are It is evident three inches long and the cross-section area v of a Hue is 45 square inches.

If the bricks are four inches deep the surface area of a Hue one brick high will be 3 x 4 x 12:1144 square inches.

A square Hue having a cross-section area of 45 square inches would be approximately 6.7 inches on a side and the surface area of a section of Hue one brick (4 inches) high would be 6.7 x 4 x 4:1072 square inches. From the above calculations it will be seen that my Hue shape gives 36.8 squaie inches more surface in four inches of Hue length than a square Hue having exactly the same cross-section area. This is an increase of 34.3% over the square Hue and is of great advantage in absorbing heat from the hot gases and allowing the cold air to absorb the heat from the brick.

Another important advantage oiE my invention over all previous Hue structures is that there are no continuous rows of bricks butting against each other and causing dis tortion of the structure and cracking of the walls when the bricks expand and contract when hea-ted and cooled.

I do not limit my invention to the specilic form shown or to any particular size of brick and it will be evident to those skilled in the art that bricks of other sizes, shapes and proportions than above described can be used to carryout my invention.

I claim: l

l. In a regenerative stove, a Hue structure having vertical Hues, the walls of said Hues being composed of rectangular brick laid up in courses one upon the other, said Hues be ing cross-shaped on a plane perpendicular to their vertical axes and extending substantially the full height of the Hue structure.

2. In a regenerative stove a Hue structure having cross-shaped Hues laid up of rectangu-` lar brick the alternate courses of which are identical and the intermediate courses oilset so that the joints between the bricks of the alternate courses are bonded by the bricks of the intermediate courses. i

3. A Hue structure having vertical Hues, said Hue structure being laid up of rectangular bricks and said Hues being cross-sliaped in horizontal cross-section, said rectangular bricks being laid in courses, said courses being so laid that the bricks of alternate courses could be exactly superimposed on each other and the bricks of the intermediate courses between saidalternate courses could also be exactly superimposed on each other, said al-V on' said iirst named lcourse,theindividual bricks saidsecond'course having. the. same positions relative to` each other tliatfthe` bricks of-said first named coursehave but the entire second ycourse being Voffset relative to saidfirst course so that the Hue openings of bothcourses will correspond and the bricks -of said second course will ibond thejoints between-the bricks of said first course; and .i

continuing laying up `alternate courses exactly corresponding toSaid-Hrst` and second coursesl until the ldesired Hue lengthV is obtained. w

5. A Hue structure having ,Huesv cross-- shaped on a plane perpendicular to their -lon-` bricks of the coursebelow, said cross-shaped Hues extending subst-antiallythe `full height-1 of the Hue structure.

6. A Hue ystructure having Hues `cross-l shaped cna plane perpendicular to `their lone. v gitudinal axes laid up of rectangular bricks nwhicheach individual Hueiis surrounded by the same thickness `of brick assurroundsw Hues laid up of rectangular bricks in which eachV brick is free from contact with other bricks on at least one end and is free from Contact with other bricks on at least one-half of its total side surface.

8. The method of laying up Hue structures p having Hues cross-shaped on a plane perpendicular to their longitudinal axes comprising spacing the bricks so that each brick can expand into a cross-shaped Hue opening.

sisting of parallel double rows of brick threel units long and one unit Wide, said parallel rows being composed of two adjacent single e y rows of brick laid end to end with one unit space between their ends and the bricksv in .each of the two single rows bridging said space between the ends of the brick in the adjacentrow, said .parallel double rows of brick being spaced apart four units, the space between said parallel double rows of brick being occupied by brick two units long and one unit wide, saidk two unit long bricks being laid so as to complete the Walls of said crossshaped Hues. A

10. VA Hue structure having vertical Hues crosseshaped in horizontal cross-section laid up of superimposed courses of two sizes of rectangular brcks,`both of said sizes of bricks being of the salme. width and depth, but `the smaller of said. sizesl of bricks being two-thirds asv long; as the larger of said Sizesl of bricks, each cou-rse being laid up of parallel, spaced 5 apart double rows of said larger bricks, the space between saidparallel double rows being occupied by zigezag rows of said smaller bricks placed with their longitudinal axesA at ninety degrees to the longitudinal axes of 10 said larger bricks, said parallel double rows of said larger bricks being composed of two single rows of said larger bricks, eachVv brick of each single row being spaced apart endwise a distance equal. to the width of a brick, said single rowsbeing'offset so that. each brick of each singlel row bridges the space between thek ends of the' adjacent bricks in the adjacent single row, and each zigzag row of smaller bricks being laid in so tlf-at a snia-lll brick butts 20 agairnstvthe center of one'side of each of saidr larger bricks whichmake up said parallel double rows and other small bricksr lie midway between said? spaced apart dou-ble rows of said larger bricks with one-'half of each otheir opposite side surfaces adjacent the side'surfacesof the adjacent smaller brickswhich* butt against saidv larger bricks;

" ALFRED O. NELSON;

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