US2395580A - Steam generator - Google Patents

Description

Feb, 26, 1946. N. G. QvARFoRDT 2,395,580

STEAM GENERATOR Filed Dec. 22. 1942 2 Sheets-Sheet 1 IN VEN TOR. BY Ni/S Qvaryfd A TQ'ORNE Y Feb. 26, 1946. N. G. QVARFQRDT STEAM GENERATOR Filed DBG. 22, 1942 2 Sheets-Sheet 2 I N VEN TOR.

OOOOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOOOOOOOOO O OOOOOOOOOOOOOOOOOOOOOO OD A TTORNE Y Patented Feb. 26, 1946 UNIT-ED STATE STEAM GENERATOR Nils G. Qvarforat, Wadsworth, ohio, 'assigner to The Babcock & Wilcox Company, Rockleigh, N. J., a corporation of New Jersey Application December 22, 1942, Serial No. 469,803

v'V7 Claims.

This invention relates to the construction of the setting walls of a fluid heater which are exposed to high temperature conditions in operation, and more particularly, tovsuch portions of a setting wall through which fluid heating tubes pass for connection tov external headers and the The main object of my invention is the provision of an improved fluid heater setting Wall construction which is capable of withstanding exposure to high temperature heating gasesfor prolonged periods of operation without buckling or distortion while permitting relative expansion and contraction of adjacent wall portions. A more specific object is the provision of an irnproved wall construction for the portion of a steam boiler setting opposite a group of fluid heating tubes of relatively low heat absorption capacity', such as steam superheater tubes.

The variousv features of novelty which characterize my invention are pointed `out withv particularity in the claims annexed to and forming a part of this specication. For a better understanding of the invention, its operating` advantages and specific objects attained by its use, reff erence should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of my invention.

Of the drawings:

Fig. 1 is a sectional elevation of a three-drum separately fired superheater single uptake steam boiler incorporating my invention;

Fig. 2 is a vertical section taken on the line 2-2 of Fig. 3;

Fig. 3 is a partial ,horizontal section taken on the line 3 3 of Fig. 2;

Fig. 4 is a broken enlarged View of a portion of Fig. 3; and

Fig. 5 is a vertical section taken on the line 5 5 of Fig. 4.

In the drawings, I have illustrated my invention as embodiedin a three-drum separately red superheater single uptake steam boiler of the type disclosed in a copending application of E. J. Rooney, Serial No. 228,734, filed Sept. 7, 1938.

The steam generating unit illustrated comprises a setting ID of substantially rectangular transversely elongated cross-section, a horizontallyarranged steam and water drum II extending longitudinally thereof, a laterally oiset lower water drum I2 arranged along one side thereof and connected to the drum I I by a relatively wide inclined bank of bent steam generating tubes I3. The tube bank I3 extends the full depth-of the setting, the front and rear walls I4 ofwhich are mainly formed by refractory. 'At the outer side of the tube bank I3 is a vertical side wall I6 which unites with the walls I4 and roof I 1 to form a gasoutlet flue It! at the Aouter side of the tube bank. Abank of economizer or air heater tubes I9 can be advantageously located in the outlet flue I8. Y

At the inner side of and below the tubebank I3-is a main furnace chamber 20 redbya plu-v rality of uid fuelburners 2I in the front wall I4. The remaining portion of thesetting is utilized for the location of steam superheating surface and an independently redv auxiliary furnace chamber Afor regulably heating the superheating surface. As shown; a small diameter waterdrum or header 25 is arranged at the opposite side of the main furnace chamber and directly below the steam and water drum I I, being connected to the drum II by transversely spaced groups of vertically extending water tubes 26,21, and 28. The tube rows 26 areA arranged adjacent the main combustion chamber. The lower portions of these tubes are provided withprojecting studs` and refractory to form` a "closed tube baille or partition 2lia extending from the drum 25 to the upper level of the burners 2 I. The tubes 21 are of larger diameter than the tubes 26 or'28 and arranged in pairs. The tubes 21 act as columns supporting the steam and water drum II and also serve as supports for horizontally arranged superheater tubes 29 and y3i) positioned between the - tube groups 28 and 26. f y Y Y l The superheater tubes 23 are of the multilooped type and'arranged with their tube legs in vertical alignment and extending throughv supporting plates 3l carried bygthe water tubes 21 therebetween. The ytubes 29- have their looped portions adjacent the side walls I4 and their end tube legs connectedto a-,pair/ of external vertically arranged headers 32 and 33 adjacentwthe same side wall I4. The superheater tubes30 are of U'shaped form and arranged in nestedrcws supported by tubes 2 between the legs thereof as describedV and with theirends connected to the header 33 and a similarly arranged headerY 34 adjacent thereto. steam inlet header, theheader 33 as the intermediate header, and the header 34 as the steam outlet header. The superheatertubes 29 `and 30 do not extend the full distance between the drums II and 25. The space between the upper end of the superheater and Vthedrum II is closed by a baffle 3S formed on the tubesv 28,while the space between the lower end and the 'drum 25v is closed by asimilar baille 31. Y y The rows of tubes 28 are arranged in staggered relation at the-opposite-side of the superheater from the main furnaceand serve asa kwater tube screenA between the superheater tubesand an auxiliary furnace chamber kIll) occupying the remaining portion of the setting. y 'The chamber I0 extends the full width of the setting with its remaining sides defined by thetube rows'28, refractory bottom 23, a vertical .ollter'slde-wall 24,;

The header 32 serves as the' fractory covered construction, while the tubes in A the remaining portion of the side wall, roof and baille are of partly studded construction, th-us providing a refractory-faced construction inthe forward portion of the auxiliary furnace and alternately cold surface and refractory in the rear portion. The auxiliary furnace chamber is iired by fluid fuel burners 43 in the front wall I4. The setting also includes an outer casing 50 spaced `from the refractorywalls 'and roof to provide-a space -`I A"through'Ywhich 'combustion air is supplied under pressure to the fuel burner ports in the front walllrl'lf'4. AThe casing 150 also serves to enclose Watersupply or downcomer connectionsfrom-'the 'drum II to `the several generating sections o'f the i the described construction the 'steam genera-ting unit is started -up with only main furnace chamber burners 2l in'use. The heating gases generated -b'y the fuel burning in suspension therein flow transversely' of the tube bank I3 and the gas outlet flue fI-B passing rover the heat exchanger I-19 before leaving the unit. The huid-cooled partition Z6 and tubes r26 'form -an effective radiant heat shield 'between the 'mainffurnace chamber andthe superheater tubes 29 eand 3U. When suf-- cients'team is Yflowing through-superheater tubes 29 and '30 the iauxiliary 'furnace chamber burners 43ers started up `and regulably operated to control the -superheat temperature. The heating gases'generated the auxiliary furnace chamber new `substantially 'horizontally lacross the -rows of screen tubes 28 and superheater tubes 29 and 30 throughout their length. After leaving the superheater' tubes these gases flow across the tubes 26 and over the upper end `of the partition 26' through the extreme upper portion 'of the main iur-nace chamber '20. The gases then pass acrossthe 'upper end of the tube bank I3 tothe gasoutletue I8. Y l 1 The superheaterfheaders', 33 and r34 areex-` ternally arranged to protect the same from direct furnace hea't mid Contact with the highten'iperature heating lga'seslfrom the auxiliary .furnace chamber f40. Ordinarily 'such headers 'are separatedffrom theheatng gas now path by fa metal protection plate perforated for the passage ltherethrough fof ithe'superheater tubes for connection to the headers, ;.Eve`n when the protection plate is of "a high heat resistant alloy, vthe 'plate portions Snot 'immediately adjacent to a 'superheater tube seas to benent-Irom its cooling effect will tend 'fto disintegrate. Where the superheater tubesare of the-inulti-'looped type, thereby eX- posin'g considerable plate sur-face between adjacent headers through 'which no superheater tubes project, fthe 4disintegration of 'the protection plate is rapid and severe. 'Y In accordance withmy invention, the vportion of the setting wall I4 at the header end of the superhe'ater tubes-29 iis `constr-u'c'ted'to withstand the :severe 'temperature `conditions present, without requiring anyehange in position of theheaders 321ior 133 -or substantial increase in thickness oriWe-g'litof'thsfwall `portion. As vshown in 3; the-sidewalls I4 are formed of` dense rebrick Ill'l backed v`up insulating 'brick' I4", vexcept in the `wall areaoppositexthe header end of the suf perh'eater tubes *'33 and BU. The wall portion at header 33 extends beyond the tubes 29 connected to that header and terminates in a vertical out- Wardly extending flange 58. In view of the substantial cool'ihg'effect'of the tubes 3|) in contact VVwitlrtlie plate 55, 4the described construction is g adequate for the temperature conditions to which it 'is normally exposed.

The :portion of the inner wall I4 opposite the ylooped portions at the header end of the tubes 29 is 'given a 'special construction l'to enable it to withstand the higher lhamperattire vconditions to which it is normally exposed :in operation, yet without ifeouiring any change 1in locationvor construction of the associated headers 32 and 33. This wall sectionis 'formed by a row -of spaced vertical ,water tubes 60 having their upper `and lower "ends 'bent rearwardly and 'connected to the upper and lower drums I'I and 2'5 respectively. The tubes u are 'of the partially studded "type, having metallic vstuds 61 projecting from z'opposite sides thereof into 'the fintertube'spaces. Each tube falso has one or two vertical yrows of verticallyelongatedmetallic plates 62 preferably'welded to the tubes and Istuds at the inner side of the wall and extending falongthe inner studs to a point substantially in contact with the plates from the adjacent water tubes Itill. The plates 62 'form a retaining 'wall for a lsuitable high temperature V resistantll'er material o3, :such 'as plastic chrome ore, positioned in theintertube spaces. .'Ihe tubes 60, studs 6I, retainer plates '62., and .filler material 63 thus cooperate to .form 'a water cooled panel wall section of high heat :absorbing 'capacity .adjacent the .looped portions of the 'superheater tubes 29 for the full length of 'the superheater headers 32 and 33..

The provision `of 'a 'Water cooled -panel wall isection in this location creates a differential expansion condition between the water cooled Wall section and the adjacent superheater headers and tubeends. To pei-mitsuch relative vertical expansion and contraction Ahanged plates G5 'are Welded to the outer row of fstu'ds 'adiacent the protection plate flange 58 and the flanges bolted together through vertically elongated slots :as indicated at 66 to permit relative vertical 'movement of the flanges.

At the opposite side of the water cooled wall section a metallic plate 6:1 is secured -to the adjacent wall portion and header 32 and carries a finger plate 68 which fits around the iirst 'water 'tube f'll with .its flanged 'end `in sliding contact with iinger plates B5 mounted on the rear portion of the .iirst `tube 6u.' The .plates 61 and `68 are'fur'th'er protected by a brick' ledge I0 which projects inwardly vfrom the wall I4 and a Vstud tube baffle 'II :extending between the two :adjacent tubes 28 for the full height of the superheater. The heating fgas :dow vis thus deec'ted suiilciently to minimize 'direct nipingement of 'thegases on these plates. '.l'hefspaces between the hea/ders 32., 33 'and 34 :and between the headers 32 and 34 and vthe 'adjoining Vrefractory portions of the wall I-d are 'sealed by packing 13 and suit ablefsliding :seals '14 to separate the space occupied by the panel 'wall :section from 'the air space 5I..

The 'described wall 'construction v.for v'the superhe'at'er `section *ofthe unit provides an Ieffective closure for this section without necessitating relocation or modification of the superheater headers or any substantial increase in weight of the wall. The amount of steam generating surface is increased Without increasing the space requirements of the unit. Diierential thermal expansion and contraction of the associated p-arts is facilitated with the described wall construction.

While in accordance with the provisions of the statutes I have illustrated and described herein the best form of the invention now known to me, those skilled in the art will understand that changes may be made in the form of the apparatus disclosed without departing from the spirit of the invention covered by my claims, and that certain features of my invention may sometimes be used to advantage without a corresponding use of other features.

I claim:

l. In a iiuid heater having a setting wall, a pair of horizontally spaced vertical headers positioned at the outer side of said wall, and a bank of horizontally arranged multi-looped tubes having horizontally spaced tube legs projecting through said wall for connection to said headers, the improvement which comprises a wall section between said projecting tube legs having a row of spaced vertical tubes, means closing the intertube spaces in said row including metallic studs on said vertical tubes projecting into said intertube spaces, refractory material surrounding said studs, and retainer plates secured to the inner sides of said tubes and arranged to hold said reiractory material in position, and relatively movable connecting means forming a slidable joint between said wall section and the adjacent setting wall portions.

2. In a steam generator having a setting wall, an upper steam and water drum, a lower water drum, spaced groups of vertical water tubes connec ting said drums, a pair of vertical steam superheater headers positioned at the outer side of said wall, a bank of horizontally arranged multilooped superheater tubes between said water tube groups and having horizontally spaced tube legs adapted to project through said wall for connection to said headers, a wall section between said projecting tube legs having a row of spaced vertical water tubes having their ends connected to said upper and lower drums, means closing the intertube spaces in said tube row including metallic studs on said vertical water tubes projecting into said intertube spaces, refractory material surrounding said studs, and retainer plates mounted on said vertical water tubes and arranged to hold said refractory material in position, and relatively movable connecting means forming a slidable joint between said wall section and the adjacent setting wall portions.

3. In a fluid heater having a setting wall, a pair of headers positionedat the outer side of said wall, and a bank of tubes having spaced tube legs projecting through said wall for connection to said headers, the improvement which comprises a panel wall section between said projecting tube legs having a row of spaced wall cooling tubes extending substantially parallel to said headers, means closing the intertube spaces in said row, and relatively movable connecting means forming a slidable joint between said panel wall section and the adjacent setting wall portions constructed and arranged to provide for relative thermal expansion and contraction between said panel wall section and said tube legs and headers.

4. In a huid heater having a setting wall, a

pair of headers positioned at the outer side of said wall, and a bank of horizontally arranged multi-looped tubes having horizontally spaced tube legs projecting through said wall for connection to said headers, the improvement which comprises a wall section between said projecting tube legs having a row of spaced vertical wall cooling tubes, means closing the intertube spaces in said row, and relatively movable connecting means forming a slidable joint between said wall section and the adjacent setting wall portions connected and arranged to provide for relative vertical thermal expansion and contraction between said wall section and said tube legs and headers.

5. In a steam generator having a setting wall, a pair of horizontally spaced vertical steam superheater headers positioned at the outer side of said wall, and a bank of multi-looped superheater tubes A,having horizontally spaced tube legs projecting through said wall for connection to said headers, the improvement which comprises a wall section between said projecting tube legs having a row of spaced vertical water tubes, means closing the intertube spaces in said row, and relatively movable connecting means forming a slidable joint between said wall section and the adjacent setting wall portions constructed and arranged to provide for relative vertical thermal expansion and contraction between said wall section and said superheater tube less and headers.

6. In a steam generator having a setting wall, an upper steam and water drum, a lower water drum, spaced groups of vertical water tubes connecting said drums, a pair of vertical steam superheater headers positioned at the outer side of said wall, a bank ofV multi-looped superheater tubes between said water tube groups and having horizontally spaced tube legs adapted to project through said wall for connection to said headers, a wall section between said projecting tube legs having a row of spaced vertical water tubes having their ends connected to said upper and lower drums, means closing the intertube spaces in said tube row, and relatively movable connecting means forming a slidable joint between said wall section and the adjacentI setting wall portions constructed and arranged to provide relative vertical thermal expansion and contraction between said wall section and said superheater tube legs and headers.

7. In a steam generator having a setting wall, an upper steam and water drum, a lower water drum, spaced groups of vertical water tubes connecting said drums, a pair of vertical steam superheater headers positioned at the outer side of said wall, a bank of horizontally arranged multilooped superheater tubes between said water tube groups and having horizontally spaced tube legs adapted to project through said wall for connection to said headers, a wall section between said projecting tube legs having a row of spaced vertical water tubes having their ends connected to said upper and lower drums, means closing the intertube spaces in said tube row, relatively movable connecting means forming a slidable joint between said wall section and the adjacent setting wall portions constructed and arranged to provide for relative vertical thermal expansion and contraction between said wall section and said superheater tube legs and headers, and a vertical ledge on the inner side of said setting wall arranged to deflect heating gases away from said wall section.

NILS G, QVARFORDT.

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