US2880973A - Drum attemperator - Google Patents

Description

April 7, 1959 I. L. LANGVAND 2,880,973

, DRUM ATTEMPERATOR Original Filed March 12, 1946 v 3 Sheets-Sheet 1 INVENTQR JVQrZLaHgVaHd ATTORNEY' April 1959 LANGVAND 2,880,973

DRUM ATTEMPERATOR Original Filed March 12, 1946 3 Shee ts-Shee't 2 Fig.2

INVENTOR [Varli lanyl and W ATTORNEY April7, 1959 LANGVAND 2,880,973

DRUM ATTEMPERATOR Original Filed March 12, 1946 3 Sheets-Sheet 3 INVENTOR [Var IZL anyvand ATTO R N EY DRUM ATTEMPERATOR Ivar L. lLangvand, Barberton, Ohio, assignor to The Babcock & Wilcox Company, Rockleigh, N.J., a corporation of New Jersey Original application March 12, 1946, Serial No. 653,843,

now Patent No. 2,633,831, dated April 7, 1953. Divided and this application April 3, 1953, Serial No.

4 Claims. 01. 257-239 The present invention relates in general to heat exchange apparatus of a class known as attemperators in which fluids of different temperatures are brought into heat transfer relation with each other for the purpose of reducing the temperature of one of the fluids. More specifically, the invention relates to the construction and operation of an attemperator in which a superheated vapor such as steam, at relatively high temperature, is directed through conduits submerged in liquid of substantially lower temperature.

The present application is a division of the prior copending application Serial No. 653,843, filed March 12, 1946, and now Patent No. 2,633,831, granted April 7, 1953.

The invention is especially adapted for use in a vapor generating unit or boiler wherein superheated vapor is directed through an attemperator having vapor conducting elements which are disposed in the path of liquid flowing through a drum or other pressure vessel of the boiler and/or furnace wall cooling means associated therewith.

In a specific embodiment of the invention, the attemperator is desirably installed within a lower submerged drum of a fuel-fired vapor generating unit arranged for natural circulation of liquid therethrough. For convenience of identification, the attemperator as thus arranged is suitably termed a drum attemperator and consists of one or more bundles of tubes connected to inlet and outlet headers. The tube bundles are suitably proportioned so as to permit installation and removal through a manhole in an end wall of the drum. Inlet and outlet connections are made through openings in the circumferential wall of the drum where specially formed fluid tight joints are provided to allow for differential expansion of the connected components.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated and described.

Of the drawings:

Fig. 1 illustrates, in sectional front elevation, a form of vapor generator or boiler particularly adapted for use of my invention;

Fig. 2 is a sectional plan view of the boiler illustrated in Fig. 1, taken along line 2--2;

Fig. 3 is a fragmentary rear elevation, partly broken away, illustrating connections between a superheater and an attemperator, both associated with the boiler;

nited dtates Patent Q Fig. 4 is a longitudinal section through the lower boiler drum, taken along line 44 of Fig. 3, showing the attemperator; and

Fig. 5 is a transverse section through the lower drum, taken along line 55 of Fig. 4.

In more detail, the vapor generating unit illustrated in Figs. 1 and 2 is formed as an integral furnace boiler ice having a setting of substantially rectangular horizontal cross section generally defined by upright front and rear Walls 10 and 11, respectively, together with opposing upright side walls 12 and 13, the space within the setting being partitioned as by an upright interior partition wall 14 to provide a boiler tube space 15 laterally adjoining the upper portion of a furnace or combustion chamber 16, the side wall 13 being extended over the combustion chamber to form an upper enclosing wall or roof 17. The combustion chamber extends downwardly below the level of boiler space 15 where its lower end is suitably formed as an ash hopper 18 having inclined side wall or floor portions 19 and 21 converging downwardly toward a rectangular throat passage 23 for discharging ash or other solids into an ash pit 24 positioned therebelow. In the construction disclosed, the inclined hopper walls 19 and 21 are essentially lower extensions of the upright setting wall 13 and partition wall 14 respectively which thus constitute the side walls of combustion chamber 16. One or more burners 25 of a type suitable for the fuel to be burned are installed in association with the front Wall 10, for example, to provide a source of heating gases. Air for combustion is supplied to the burners through a windbox 26 to which air under pressure is supplied by the customary forced draft fan.

The partition wall 14 extends from the front wall it to a location spaced from the rear wall 11 whereby a passage 27 is provided for heating gases flowing from the combustion chamber 16 into the boiler space 15. Transverse bafiles 28 and 29 extending partially across boiler space 15 provide serially connected gas passes 31, 32 and 33 through which a substantially horizontal flow of heating gases is maintained from the combustion chamber 16. A soot hopper 34 is formed at the bottom of boiler space 15 adjacent the side wall 12, and a dis charge opening 35 provided below each of the gas passes 31, 32 and 33, the lower end of bafiie 29 extending across soot hopper 34 to prevent the bypassing of heating gases around tubes in passes 32 and 33. If desired, a separate wall member may be utilized for the same purpose. The spent gases are discharged from the boiler space 15 through a gas outlet, not shown, suitably from an upper portion of the final pass 33 as disclosed in the aforesaid copending application.

The boiler includes upper and lower drums 38 and 39, respectively, having their longitudinal axes in a common substantially vertical plane, the drums being connected by a bank of upright boiler tubes 41 disposed within the boiler tube space 15 between front and rear walls 10 and 11. In the embodiment disclosed, the boiler bank tubes 41 have the major portions of their lengths straight and vertically disposed with their upper and lower end portions bent to enter the respective drum walls radially, such tubes being suitably arranged in parallel rows extending longitudinally of drums 38 and 39, preferably with the tubes 41a in the first pass 31 larger in diameter and more widely spaced than tubes 41b in either of the succeeding passes 32 and 33. The tubes of bank 41 include tubes contiguous to both sides of each baflle 28 and 29, such tubes serving to cool and support the battles and comprising tubes 41c and 41d in transverse rows along opposite sides of bafile 28, and tubes 41m and 4111 in other transverse rows along opposite sides of baflie 29.

Each of the setting walls 10, 11, 12, 13 and partition wall 14 comprises at least one row of fluid cooling tubes 10a, 11a, 12a, 13a and 140, respectively, suitably connected to drums 38 and 39 to provide natural circulation flow paths in parallel with the boiler bank 41. In the front and rear walls 10 and 11, the tubes 10a or 11a, as the case may be, have their lower ends connected to a. header 43 and their upper ends to a header 45, each lower header 43 being connected to the lower boiler drum 39 through make-up connections 46, and each upper header 45 being connected to the upper boiler drum 38 through riser connections 47. Other tubes b and 11b adjoining portions of front and rear walls 10 and 11, and tubes 12a adjoining side wall 12, have their upper and lower ends connected to drums 38 and 39 as in the case of boiler tubes 41.

In wall 13 which defines the outer boundary of combustion chamber 16, the tubes 13a have their lower ends connected to a side wall header 48 having make-up connections 49 from the lower boiler drum 39, the upper ends of tubes 13a being connected to the upper boiler drum 38 in rows circumferentially spaced from the upper end connections of boiler bank tubes 41.

In wall 14 which defines the inner boundary of combustion chamber 16, the tubes 140 have their lower ends connected to a side wall header 51 to which make-up connections 52 are provided from the lower boiler drum 39, the upper ends of tubes 140 being connected to the upper boiler drum 38 in rows intermediate the upper end connections of tubes 41 and 13a. In the inclined hopper wall 21 the tubes 140 are arranged in a single row at center-to-center spacings substantially equal to their diameters, the same as indicated for rear wall tubes 11a and side wall tubes 13a. Above hopper wall 21, the tubes 140 may be regarded as comprising three groups 14a, 14b and 140, as determined by their form and arrangement. In group 14a the tubes are extended upwardly in a single row to form the upper portion of wall 14 which partitions the boiler space from the furnace chamber 16, the spacing of tubes 14a being the same as tubes 140 in hopper wall 21, and certain tubes 14a being bent out from the longitudinal plane of the partition to form a relatively narrow extension bafiie 53 to further the redistribution of heating gases before entering the first pass 31. In groups 14b and 140 the tubes extend upwardly across the entrance to gas pass 31 in rows paralleling the rows of boiler tubes 41, the tubes 14b being arranged in a single row at center-to-center spacings of twice their diameters, while tubes 140 are arranged in two rows, and staggered, at center-to-center spacings of four times their diameters in each row, thereby forming a slag screen.

A superheater 56 is positioned in the first pass 31 rearwardly of the slag screen and between spaced rows of boiler tubes 41a, the superheater comprising upwardly extending loops formed as U-tubes 57 and 58 connected to inlet, intermediate and outlet headers 59, 61 and 62, the inlet connections 63 for conducting steam or other vapor to inlet header 59 extending downwardly along side wall 12 between spaced tubes 12a. A bafile 64 extends upwardly from drum 39 and across the superheater loops to protect headers 59, 61, 62 from the hot gases entering the first pass 31, the bafile 64 also defining the lower boundary of the passage available for gas flow over the superheater tubes. A baflle 65 supported on a row of boiler tubes 41a extends downwardly from upper drum 38 to partially close ofi the space between the drum and the upper ends of the superheater loops, thereby confining heating gas flow substantially to the space occupied by superheater tubes and promoting greater uniformity of gas distribution thereover. Bafile 65 is suitably made in removable sections to permit adjustment of the space through which gases may bypass superheater surface.

The superheater 56 in first pass 31 is of the multipass type having each of its headers 59, 61 and 62 transversely divided as by a partition wall 91, as indicated in Fig. 2, to provide primary sections 59a, 61a, 62a adjacent bathe 28, and secondary sections 59b, 61b, 62b, adjacent rear wall 11. Vapor delivered to primary inlet section 59a flows through the associated loops 57 into primary intermediate section 61a and thence through associated loops 58 into primary outlet section 62a, thus completing a primary stage of superheating.

The initially superheater vapor is discharged from the bottom of the last named section through pipe 92 to regulating valve 93 from which a portion of the vapor may be directed through pipe 94, T 95 and pipe 96 to the secondary inlet section 5912 for further superheating. Any remaining portion of the vapor from valve 93 is directed through pipe 97 to an attemperator 98 submerged within lower boiler drum 39. Desuperheated vapor is discharged from the attemperator through pipe 101 leading to T 95 in which desuperheated and initially superheated vapor portions are mingled for combined flow through pipe 96 into the end of secondary inlet section 5%.

Regulating valve 93 as shown is formed with a diaphragm 102 diametrically disposed above the level of pipe connection 97 and curved downwardly into contact with the housing below connection 97. A damper 103 generally of the butterfly type is mounted adjacent the upper end of diaphragm 102 with its spindle 104 at right angles thereto, the damper comprising semicircular blades at right angles to each other at opposite sides of the diaphragm, the spindle having a handle 105 secured thereto and being supported in bearings at opposite ends, both bearings having suitable structures associated therewith to prevent leakage of vapor.

The attemperator inlet and outlet pipes 97 and 101 enter drum 39 through a specially formed drum section 107 which is circumferentially welded along opposite edges as at 108 to the main drum length 109 and drum head 110, respectively, the insert section 107 having oppositely disposed aligned integral push-out portions 112 ofiset from the central longitudinal drum axis and of the required internal cross section to provide clearances about pipes 97 and 101. Relatively thin metal cylinders or sleeves 113 are peripherally welded at their inner ends 114 to the respective push-outs 112, and at their outer ends 115 to the respective pipes 97 and 101, each sleeve at its inner end having an internal circular cross section substantially equal to that of a push-out 112, and at its outer end, an internal circular cross section corresponding to the outer cross section of a pipe 97 or 101. By this construction, fluid tight joints are maintained between pipes 97 and 101 and drum 39 under the severe conditions imposed during service, due for example to temperature difierentials between the superheated vapor and the boiler liquid, and the wide variations in vapor temperatures which may accompany the desuperheating process.

The attemperator 98 comprises circumferentially spaced bundles of horizontally disposed U-tubes 116 connected in parallel between inlet pipe 97 and outlet pipe 101, the tube bundles 116 extending, for example, beneath the first and second gas passes 31 and 32, and preferably to the exclusion of the last pass 33 in the region of downfiow boiler tubes. Superheated vapor entering through pipe 97 is conducted through inlet tubes 117 and 118 to inlet boxes or headers 119, thence through the respective U-tube bundles 116 to outlet boxes 120, and thence through outlet tubes 123 and 124- to outlet pipe 101. Each tube seat face 125 of junction boxes 119 and is of hexagonal formation providing space for tubes 116 in three rows parallel to its longest straight margin 126, two rows having four tubes each and the third row, two tubes. Such a construction permits compact assembly of the inlet and outlet boxes 119 and 120 of each bundle, and enables the entire attemperator assembly to be positioned, as shown, so as to minimize obstruction to liquid fiow to and from tubes connected to the drum. The provision of the non-radial push-out nozzles 112 for the inlet and outlet steam connections of the attemperator, when positioned at the bottom of the drum as shown, results in a clear space above the horizontally extending attemperator tube loops affording a Working access to the lower ends of the boiler tubes. An access man-hole 111 of adequate size in the adjacent drum head is also an advantageous feature of the arrangem'ent.

While in accordance with the provisions of the statutes the inventor has illustrated and described herein the best form of the invention now known to him, 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 the claims, and that certain features of the invention may sometimes be used to advantage without a corresponding use of other features.

What is claimed is:

1. In a boiler having a horizontally arranged lower drum normally filled with circulating boiler liquid and having spaced tube openings in the upper portion of the circumferential wall thereof for boiler liquid circu lating tubes, said drum having a pair of non-radial openings formed in the circumferential wall thereof spaced from said tube openings, a submerged steam attemperator within said drum comprising an elongated tube bundle extending longitudinally of said drum and spaced from said tube openings to provide access to said tube openings, means forming steam inlet and outlet connections extending through said circumferential wall to said tube bundle, each of said connections comprising a tubular conduit extending substantially horizontally in a non-radial chordal plane of said drum through one of said drum circumferential wall openings and having an outer crosssectional area less than the inner cross-sectional area of the corresponding drum opening, and sleeve means connecting the peripheral portions of each of said drum wall openings to the outer side of the corresponding conduit and arranged to define a horizontally extending annular space communicating with the drum interior and surrounding the portion of the conduit at and externally adjacent the drum wall opening for the circulation of boiler liquid therein.

2. In a boiler having a horizontally arranged lower drum normally filled with circulating boiler liquid and having spaced tube openings in the upper portion of the circumferential wall thereof for boiler liquid circulating tubes, said drum having an intermediate length portion adjacent its end closure in the form of a relatively narrow generally cylindrical insert section joined along its longitudinally spaced circumferential edges to the main drum length portion and to said end closure respectively, said drum insert section having outwardly extendingly non-radial push-out portions formed integrally therewith, an attemperator within said drum comprising an elongated tube bundle extending longitudinally of said drum and spaced from said tube openings to provide access to said tube openings, said attemperator having an inlet and an outlet connection thereto each extending substantially horizontally in a non-radial chordal plane of said drum and through a separate oneof said push-out portions, each of said connections having an outer cross sectional area less than the inner cross sectional area of the push-out through which it extends thereby providing a continuous clearance space therebetween, metal sleeves each surrounding one of said connections and having one end matching and adjoining the perimeter of the associated push-out, and means for securing said sleeves to the perimeters of said push-outs and connections.

3. In a boiler having a horizontally arranged lower drum normally filled with circulating boiler liquid and having spaced tube openings in the upper portion of the circumferential wall thereof for boiler liquid circulating tubes, said drum having an intermediate length portion adjacent its end closure in the form of a relatively narrow generally cylindrical insert section joined by fusion-deposited weld metal along its longitudinally spaced circumferential edges to the main drum length portion and to said end closure respectively, said drum section having outwardly extending push-out portions, of circular internal cross section, said push-out portions being formed integral with said insert section and extending from opposite sides of said drum in substantial mutual alignment adjacent the bottom of said drum, an attemperator within said drum comprising an elongated tube bundle extending longitudinally of said drum and spaced from said tube openings to provide access to said tube openings, said attemperator having an inlet and an outlet connection thereto each extending substantially horizontally in a non-radial chordal plane of'said drum and through a separate one of said push-out portions, each of said connections having an outer cross sectional area less than the inner cross sectional area of the push-out through which it extends thereby providing an annular clearance space therebetween, cylindrical metal sleeves each surrounding one of said connections and having one end matching and adjoining the perimeter of the associated push-out, and means for securing said sleeves to the perimeter of said push-outs and connections.

4. In a boiler having a horizontally arranged lower drum normally filled with boiler liquid and having spaced tube openings in the upper portion of the circumferential wall thereof for boiler liquid circulating tubes, said drum having an intermediate length portion adjacent its end closure in the form of a relatively narrow generally cylindrical insert section joined along its longitudinally spaced circumferential edges to the main drum length portion and to said end closure respectively, said drum section having oppositely disposed and aligned push-out portions of circular internal cross section displaced downwardly from the longitudinal axis of said drum, said push-out portions being integrally formed with said drum section, an attemperator within said drum comprising an elongated tube bundle extending longitudinally of said drum and spaced from said tube openings to provide access to said tube openings, said attemperator having an inlet and an outlet connection thereto each extending substantially horizontally in a non-radial chordal plane of said drum and through one of said push-out portions, each of said connections having an outer cross sectional area less than the inner cross sectional area of the push-out through which it extends thereby providing an annular clearance space therebetween, cylindrical metal sleeves each surrounding one of said connections and having one end matching and adjoining the perimeter of the associated push-out, and means for securing said sleeves to said push-outs and connections.

References Cited in the file of this patent UNITED STATES PATENTS 1,823,800 Hartmann et a1. Sept. 15, 1931 1,963,731 Armacost June 19, 1934 1,964,060 Huet June 26, 1934 2,063,441 Kerr Dec. 8, 1936 2,239,230 Hartmann Apr. 22, 1941 2,271,652 Langvand et a1. Feb. 3, 1942 2,346,104 Gunter Apr. 4, 1944

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