US2666625A - Heat exchange apparatus - Google Patents

Description

Jan. 19, 1954 w. M. BYERLEY HEAT EXCHANGE APPARATUS Filed Sept. 20, 1951 ahw INVENTOR Wilbur" M. Byerley BY WY YM ATTORN EY Patented ljan. 19, 1954 2,666,625 HEAT EXCHANGE APBARATUS Wilbur M. Byerley, Crum`Lynne, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Applicatian' september 2o, 1951,'seria1No. 247,512

1 vThisinvention relates toA heat exchangers such as feedwater heaters -employinghairpin `tubes forming first and second passes, and more particularly, toa heater of thetype provided With horizontal and enveloping' baffles joined to outer and inner tube plates forisolating a portion of the first pass to form an Aintegral drain cooler, the length `of which is substantially less than that of the first pass.V Y

In constructing -a feedwater heater with f which it is desired to .provide integral drain cooler apparatus, there may be a decided thermal advantage in enclosing va section which includes all of the tubes inthe rst pass throughouta portionfof the full pass length, :to constituteA the desired 4 Claims. (Cl. 257-32) drain cooler apparatus.` It'. has Vbeen propose/da to achieve this advantage by utilizing sealing means or packing around each tube in vthe end baiiie of the cooler section.. In order to minirnizeleakage,l howevenit is desirableto expand the tubes intothe baie at the end'ofthe cooler section,' through vthe" medium ofiV a suitable, ex-V exchanger or feedwater heater having a .drain cooler section constructed in accordance with the invention;

Fig. 2 is a sectional view taken along the line II-II of Fig. 1;

Fig. 3 is an enlarged detail sectional view of the drain cooler seal structure shown in Fig. 1; and

Fig. 4 is a sectional view taken along the line IV-IV of Fig. 3.

In the drawing, there is. shown a feedwater heater including a shell I 0, a header I I having an inlet compartment I2 and an outlet compartnent I4, and a plurality of "hairpin or U tubes I5, the opposite open ends of which are'rolled into the usual tube sheet I6 of the header for communication with the inlet and outlet compartments thereof, respectively. Water to be heated is supplied to the inlet compartment I2, flows through the rst and second passes a and b of tubetfand heated water is discharged from l vA horizontaifarrd/e-/Arwelmnbame structure 23 .M /tended tube-expanding device. With-this cone e Y rrhaving one end secured to the tube sheetv I6 surstruction the paiilevismequired to move. W'Ithe Y tubesasthey expanda-nd contract. It isetlierelY L lfore, an objectof the inventiony to Yprovide an expansion jointstructure having improved sealing characteristics suitable` for use.inv the drain cooler section of such a-feedmntpv h l It is' anotherhob'ject'of the invention to`provide, in feedwater heater apparatus, Yan expansion joint between the enveloping baiile and tubes of an integral drain cooler section having tubes `which are rolled solidly into a tubesheet and enclosed by the enveloping baie, which expansion Ajoint dispenses withY flexible Vdiaphragm means and is constructed and arranged tov present favorable contour Acharacteristics avoiding weak corner portions that might be `subject to highstress concentrations. l A' further object of the invention is to provide a diierential expansion joint of the foregoing ,type comprising a plurality of overlapping and encircling strips of rust-resistant 'material wrapped around thebaieand tube plate portion of the cooler apparatusr and free to slip to permit relative expansion or contraction of Ythe tubes while minimizing leakage into the drain cooler section. Y y

These and other objects are effected by the invention as will be apparent from the following description and claims taken in connection with theV accompanying drawing, forming a.partL of this application,l in which: l fFig. 1 is a `longitudinalisectional'view 'of aheat lng rounds a portion of the first pass a of the tubes I5. `An interior tube plate 25 secured to a baiile section 23a is provided adjac i l g a e structure 23 for cooperattherewith to divide the interior of the shell I0 into `feedwater heating spaces 21 and 28. The space 21 has an entryway 21a and an outlet 21h, and is adapted to serve as a drain cooler section extending for a portion of the first pass a of the tubes I5. The larger heating space 28 has an inlet 28a and is adapted to facilitate transfer of heat from steaminto the Water flowing through the tubes I5 to effect Vconsequent condensation of the water vapor. A number of laterally disposed deflector plates 38 and 3I of smaller diameter than that of theshell I0 are mounted in the space 28 for providing staggered flow ports for effecting ilow through a tortuous flow path of the steam entering the space. Heat'- ing steam thus enters the inlet 28a adjacent the header end of the space 28, is driven to and .fro as it impinges against the deectors 30, and thence ows upwardly and downwardly around the defiectors 3|, thereby being passed in heat -exchanging relation over both passes of the tubes I5.

condensate collecting at the bottom of the shellv I!) is driven by steam pressure into the drain cooler spaceY 21, throughfthe inlet 21a, Which-'isy formed at the loWer-chordal edge -of the tube plate25. To provide foralternatefback and forth flow of condensate across the portions of the tubes it within the drain cooler space 21, lateral baiiles 42 are provided therein, with staggered upper and lower chordal edges spaced at opposite sides of the space to form suitable flow port areas. Discharge flow of condensate from the drain cooler section is effected by way of the outlet 2lb.

The tubes of the first pass a are expanded or rolled into the openings provided in the interior tube plate 25, whereby huid-tight connections are ensured. According to the inventiomas best shown in Fig. 3, an expansion joint assembly .45

- means interposed between said main portion of the4 baiile structure and said interior tube plate is provided between the bafflestructure 2.3 and:v

baffle section 23a comprising cuter and-inner circumferential sealing plates 4t and 41 carried byy and extending coaxially ofthe baille structure and separated by a relatively narrow spacer 11S, and spaced circumferential outer and inner-circumferential sealing plates 49 and 53, which are interleavedwith the sealing plates 4,5, andi? and carried by the baiiie section 23a. A narrow spacer 5i is interposed between the sealing plate 5B' and baiiesection 23a, while ther sealing plates 49 and 5e are spaced by a similar spacer 52 to provide for coaxial alignment of the respective interleaved plates of they separate elements of the drain cooler section. It will be understood that, with the sealing plates of the joint assembly 45 slidably interengaged, and with the tube plate 25 secured to portions of the tubes I5 remote from the ends thereof which are rolled inte "js-the tube sheet I6, as shown in Fig. lfany ther- Ialexpansion and: contraction o the tubes will be effected Without undesirable concentration of stressesi in the structural portions of the heat exchanger, due to the relative slipping permitted between'the interleaved sealing plates. At the same time, an effective seal is maintained by the joint assembly 45, preventing leakage of steam or-condensate irom the spaces of the heat er;-

f en shown, in bu ha e r to which those iiuids are to-beconneg" While the invv i has t portion, said expansion joint means including a plurality of overlapped, spaced plates circumferentially mounted on said bailie structure, and a pluralityor similar plates complementary to Athe Viirst-named plates and circumferentially carried by said tube plate portion, said separate groupsoi plates being slidably interengaged to provide an expansible sealed joint.

.3. Inga. feedwater heater, a horizontally disposed shell forming a heater space, a header connected to the shell and including an outer tube plate, said headerhaving'a lower inlet compartf. ment for water to be heated and an upper outlet compartment, for heated water, horizontally disposed tubes having ends joined to said outer tube plate and forming lower and upper passes for conducting Water from said inlet compartment to said outlet compartment, horizontal and enveloping baie structure joined to the tube plate and encompassing the tubes of said lower pass for a portion of the length' thereof to constitute a drain cooler/section separate from said heater space, an interior tube plate having openings for receiving said tubes and secured thereon adjacent said baie structure, said interior tube plate having arecessed lower edge forming an entrywayfor admission of condensate to said drain ooler section, a condensate discharge outlet arranged thereabove, said shell having a steam admission opening formed in the end thereof ad- Tat'e-nt` said header f and communicatingwithmsad one. form, it will be obvious to those shined-hmm? the art that it is, not so limited, but is susceptible of J various changes and modifications without meesmacsewrgnt thereof.

What is claimed is: `l

disposed shell and header structure forming a heating space, vmeans for admitting steam thereto, Water tubes horizontally mounted therein and providing first and second passes, baille structure enveloping portions 0f said tubes in one of said passes for enclosing a drain cooler section, saidv baie structure including a horizontally disposed main portion and a relativelymovable interial tube plate portion having openings in which said tubes are secured intermediate the ends thereof, said interiorl tube vplate portion having a lower recessed edge forming an entry- Wayv for admission of condensate from said heating space to said drain cooler section, and expansion joint means interposed between said main portion o1" the baille structure and said interior tube plate portion, comprising a plurality of interleaved plate elements carried by the respective main and tube plate portions of said bafe structure, said plate elementsrbeing slidably engaged in sealing relation.

2. In a heat exchanger having a horizontal shell andi a header structure forming a heater space.. means. for admitting. steam4 thereto, water tubes: horizontally mounted therein and providing. first andsecond passes, baffle structure `ell-- amemmmwwlt means 00mprising complementary plates s 1 ablyiw between-and connecting said interior tube plate and said bafe structure in sealed relation for Mghxminimizing leakage of steam from said heater l. In a heat exchanger having a horizontally spac Mn aid. drain coolerV section.

4. In a feedwater heater, a horizonta y 1sposed shell forming a heater space, a header connected to theV shell and including an outer tube plate, said header having a lower inlet compartment for water to be heated and an upper outlet compartment for heated water, horizontally disposed tubes having ends joined to said outer tube plate and forming lower and upper passes for conducting water from said inlet compartment to said outlet compartment, horizontal and enveloping baille structure ljoined to the tube plate and encompassing the tubes of said lower pass for a portion of the length thereof to constitute a drain cooler section separate from said heater space, an interior tube plate having openings for receiving said tubes and secured thereon adjacent said baiiie structure, said drain cooler section having a condensate entryway formed by a recessed lower edge on said interior tube plate and a discharge outlet arranged thereabove, said shell having a steam admission opening formed in the end thereof adjacent said header and communicating with said heater space,v and expansion joint means interposed between and connecting said interior tube plate and said baiile structure for minimizing leakageA of steam fromsaidl heater space into said 5 drain cooler section, said expansion joint means References Cited in the file o1 this patent comprising overlapping,spaced .inner and outer UNITED STATES PATENTS concentrlcally curvedy plates carrled by sa1d bafe Y structure, and overlapping, spaced inner and Number Name Date outer concentrically curved plates carried by said 5 489,944 n Worn et al -f NOV- 291 1949 interior tube plate and interleaved in slidable 215%174 Worn Sept 19 1950 sealing engagement with the first-named plates. v FOREIGN PATENTS v WILBUR M. BYERLEY. Number Country Date 398,488 France Mar. 24, 1909

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