US2920874A - Steam generator construction - Google Patents

Description

Jani K. A. GARDNER STEAM GENERATOR CONSTRUCTION 5 Sheets-Sheet 1 Filed June 22, 1955 IN VEN TOR. K wrL- Gardner BY ATTRNE YS JMJ Jan. 12, 1960 K. AIGARDNER 2,920,874

STEAM GENERATOR CONSTRUCTION I Filed June 22. 1955 3 Sheets-Sheet 2 IN VEN TOR.

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ATTUR/VEYS United States Patent O 2,920,814 STEAM GENERATOR coNsTRUcnoN Karl A. Gardner, Canton, Ohio, assgnorrto The Griscom- Russell Company, Massillon, Ohio, a corporation of Delaware Application June `22, 1955, Serial No. 517,125

3 Claims. (Cl. 257-239) extending from opposite heads at either end of the heat exchanger.

In any heat exchanger it is desirable to keep the Size of the shell and tube fluid heads as small as possible,

in order to keep the weight and 'the costV of the parts l which do not contribute to heat transfer, at a minimum. In certain applications there are further reasons for reducing the Vsize of the equipment, such as equipment within the shield area of a nuclearfreactor, or an aircraft, or in seagoing vessels. In such instances, the size and mass of otherA equipment external to the heat exchanger may be determined by factors preventing reduction of size or mass so that any minimizing of the size and mass of an associated heat exchanger may constitute the only important reduction in size or mass of the equipment as a whole that can be made.

In many processes using heat exchangers the process can continue at decreased efficiency with the heat exchanger entirely out of the circuit in the event of leakage or failure of the heat exchanger. In other processes this is not possible and a failure of the heat exchanger will interrupt the entire process unless a standby heat exchanger is provided for such emergency. Where, however, a heat exchanger is a vmajor item of equipment, considerations of economy do not permit the provision of a standby Aheat exchanger for emergency use. Likewise, where space is at a premium, such as in sea-going vessels or in a shielded area, the provision of a standby heat exchanger for emergency purposes is not practicable.

One alternative to the provision of a standby heat exchanger for emergency use is the ,compartmentation of the heat exchanger fluid'streams directed through the heat exchanger. In many cases, compartmentation of uid streams may make it possible to continue operation of the process in event of a local failure by detecting the location of the failure and shutting down the particular fluid stream affected while continuing all others in operation. In el'r'ect, compartmentation amounts to a multiplicity of standby heat exchangers in one major piece of apparatus, no one of which is capable of handling more than a small part of the total duty.

Thus, a compartmentalized heat exchanger is an answer to considerations of space and weight `limitations anda process of critical nature which does not permit the continuation of the process with the heat exchanger entirely out of the circuit. Both of the foregoing considerations of space and weight limitation and the critical nature of the process apply to the steam generator of a power plant, and particularly to a steam generator for a mobile power plant in a ship or submarine.

The steam generator construction of the present invention satisfies the requirements of space and weight limitation and critical processing. Ordinarily a compartrrnentalized heat exchanger occupies a certain minimum 2,920,874 Patented Jan. 12, 1960 Fice amount of space for a given application. Heretofore, compartmentation has been achieved with the `sacrilce of space within,the heat exchanger due to partitions between each compartment with which a given set of heat exchange tubes communicates; or with an increase in diameter of the unit to accommodate compartment partitions or connections. The present invention overcomes these disadvantages and improves the overall design of conventional compartmentalized Yheat exchangers and at the same time uses most efficiently the space within a heat exchanger of minimum lateral dimension.

It is av general object of this invention to provide a heat exchanger having a size which is as small as possible in order to not only minimize the space occupied therebyl and the overall weight of the heat exchanger but also to minimizev the cost of parts which do noteontribute directly -to heat transfer. v

It is another object ,of this invention to provide a compartmentalizedv heat exchanger having a reduced size in order to conserve space for other purposes.

It is another object of this 'invention to provide a compartmentalized heat exchanger which maybe operated at reduced efficiency in the eventof failure of a particular part thereof without interrupting operation of the entire process in 'which the heat exchanger is used.

Another object: ofthis invention is to provide 'a heat exchanger whichmay be used in the operation of processes that are critical in nature and which may not be continuously operated without a heat exchanger, such as a steam generator.

Finally, vit is an object of this invention to provide an improved heat exchanger which incorporatesthe foregoing desiderata in an inexpensive manner and with simplified maintenance and operation.H Y

These and otherfobjectsv andadvantages apparent to lthose skilled in the art from the following description and claims may be obtained, the stated results achieved and describeddifliculties overcome by the discoveries, principles, apparatus,v parts, combinations, subcombinations and elements which comprise the present invention, the nature of which is set forth in the following statement, preferred embodiments of which--illustrative of the best modes in which applicant has contemplated applying the'principles-are set forth in the following description, and which are particularly and distinctly pointed out and set forth in the appended claims forming part hereof. Y

Generally, the nature of the improved apparatus of the present invention may be stated in general terms as including, a cylindrical shell, tube sheets at opposite ends thereof, the sides of` eachtube sheet remote from the shell having a vnumber of parallel compartments separatred by partition lands, at least one partition extending centrally across the tube sheet perpendicular to the remaining partitions and providing parallel compartments Von either side of thecentral partition, at least one row of the tube-receiving openings communicating with each compartment, at least. one row of openings in one tube sheet being aligned with the lands on the other tube sheet, a U-shaped tube extending from each opening in a compartment on one side yof said central partition to an opening in a corresponding compartment on the other side of said centralpartition, the tubes extending from the openings of a particular compartment being disposed in the same plane and said plane being oiset from the plane of tubesy extending from openings in the corresponding compartment in the opposite tube sheet.

In the accompanying drawings which are illustrative of preferred embodiments of the invention, by way vof example, and in which similar numerals refer to similar parts thereof:

Fig, 5 is a fragmentary vertical sectional view 0f another embodiment of the invention .showing a modified form of construction;

Fig. 6 isa fragmentary vertical sectional view of a further modifiedA form construction having `ports communicating with the compartments extending Ain an Vyarial direction from the end ofthe head;

Fig. 7 is a fragmentary end view of the construction, shown in Fig. 6;

- Fig- 8 is a fragmentary vertical sectional view of a further modied form of construction;

Fig- 9 is a fragmentary plan sectional View on the line :9V-9, Fig. l0 of Aa further modied forni of construction; and

Fig. 10 vis an end view with parts broken away .of the construction shown in'Fig. 9.

The Vheat exchanger shown in Figs. l, 2 and 3 includes atcylindrical ,shell 1 provided with inlet Ports Zand outlet ports 3 and tube sheets 4 and 441 at either end of the shell, A plurality of dividers, 'lands or partition walls 5, spaced apart and parallel with each other, are provided on the outer side of each tube sheet 4 and 4a, `shown in Figs. l, 2 and 3 as extending preferably vertically, A central partition member 6 is also p rovided on the outer side of tube sheet 4 and located perpendicularly with respect to the spaced parallel parti- .tion members .5 and forming therewith a series of upper 4compartments 7 and lower compartments 8 (Figs. 1

and'3). Eachcompartment 7 orV 8 forms a head Compartment for one end ,of a group of U-tubes to be l later described.

The outer end of each compartment 7 or 8 is closed by a .cover lplate 9, which may be welded at 10 to the lpartition members 5 and 6 and at 10a to the circumscribing ,cylindrical wall 11 forming a projection of the A,Shell .beyond each tube sheet 4 and 4a.

Thus, ueach cover .plate 9 has a generally trapezoidal shape with one end welded .to the central partition `member 6, one orrnore Vsides welded to the spaced parallel partition walls v5 and en varcuate end oran arcuate side and end welded to the cylindrical wall 11, thereby forming a fluid-tight closure fQreach compartment 7 and 8.

Tube inlet yports 12 communicate through the cylind rical head extension Wall 11 with each upper compartment 7; and -tube outlet ports 13 communicate through cylindrical wall-1 1 with the lower compartments 8. The upper inlet ports A 1 2 at each end of the heat exchanger are ,Preferably connected together by a manifold (not shown) and the inlet port manifolds in turn are preferably connected together and communicate with a main coolant inlet :(not shown). Similarly the `outlet ports `13, may "be connected together by suitable manifolds at veach end Vof the heat exchanger, which manifolds may "the openings 14 communicating with the upper compartment of the tube sheet 4. The other ends of the U- tubes m such group are secured in the openings 14 communicating with the corresponding lower compartment 8 as best shown in Figs. 1 and 3. Similarly, other groups of U-tubes are secured in openings 14 in the tube sheet 4a communicating with the upper and lower compartments 7 and 8 of the tube sheet 4a. As shown in Fig. 2, the spaced parallel tube sheet partition walls 5 in the tube sheet 4 are offset laterally with respect to the spaced parallel partition walls 5 in the tube'sheet 4a so that planes passing through the center lines of the partition walls 5 in tube sheet "4 lie generally in the planes o'f the center lines of each group of U-tubes 15 connected to tube sheet 4a and vice versa. In this manner, the groups of U-tubes connected with the tube sheets 4 and 4a are interleaved without loss of space on the face of the tube sheets because of the provision of the partition ribs or members 5, as would be the case if all U-tubes entered a single. tube .Sheet Provided with partition ribs for obtaining@oorrmartrueotatiou- A' :E clarity of illustration, the tubes, .tube Snaciug tube size, etc .are shown Somewhat diasra'raruaticahy iul Fies- 1, 2 and 3, it being understood that the tubes may be .of ylarger relative diameter than shown and more closely Slledito provide agreater number of tubes so `as to locate a maximum amount of tube surface within the shell 1.

In operation, coolant flowing from .the main coolant inlet will enter the tube inlet ports-12 at each end of the heat exchanger and ow tothe .upper compartments 7 of the tube sheets 4 and 4a, thence through the 1-tubes 15, thence -to the lower compartments 8 in each tube sheet 4 anden, thence out through the tube outlet norte 13 to ,the main -coolant outlet. At the same time, shell rliuid may fentertthe shell inlet ports 2 and pass within the shell around ,the surfaces of the lJ-.tubes 15 and out through the shell outlet ports 3 in performing the heat exchange operation- The arrangement lof zthe imprzoved construction by which our nested group of tubes communicates with its own upper and .lower head compartments 7 and 8, which .particular compartments 7 and 8 are separated from all .other compartments 7 and 8 in veach tube sheet 4 and 4a provides c 'ompartrnentation ,for vthe tubes so that in event of failure of any particular tube, it is only necessary to cut off Huid ilow to the `group ,of tubes and compartments 7 and 8 with which the failed .tube communicates7 permitting continued operation .of the heat exchanger- Meariiyhile, theiailef'i ruhe may he. repaired by oucuiuu up .the cover platee 9 ou .the compartments 'l aud 8 which communicate withthe tube failure.

.At the saine time there .has beca no Sacrifice iu Space, or :substantial increase iu .weight hy achieving compart- -mentation because VY of the interleaved arrangement of the groups ,of tubes and the connection o f vone series of tube V'groups with one tube sheet 4 ,and the connection of the otherseries .of groupsof ,tubes with Ithe tube sheet 4a. As indicated, this v,c o mpartmentation without sacrificing space isachieyed by locating vthe compartments 7 aud 3 andthe spacedparallel partition walls 5 forming the same in Vone tube sheet 4 offset withrespecttothe compartments 7 and 8 and partition walls in the tube sheet 4a at the other en d of the heatenohangen so that the U-bends of one `group `of nested LJ-tubes connected with one tube `sheet are Opposite .a partition wall 5 inthe other tube malconce ntr ation o f tubes .throughout most of the length `of the heat exchanger is hrofired- Fig- 4 ,illustrates a .moritied Y'forno `of construction iu which `tytogroupa of .nested tubeseomrhuncate with each upper compartment 7 end=-corrcenonding lower compartmeutt .Iu .thismodihed arr. gement, tworoWS of tube sheet. In this mannena compact tube bundle with nor- '.onenings vv.14a aud 1.4i arenrovidediu each ,compartment 7 `and 1.8 .with ,the .ceutersof ,the ,tubes-,ih one row of the `.tube openings ,14a located iu ,a plane Parailel to the tubo openings 14b in the other row. y-In order to accommodate interleaving of ,the groups of tubes in the construction shown in Fig. 4, the group of tubes connected with th tube 'openings 14a all lie' in the same plane, but the groups of tubes connected with the openings 14h are bent at 16 to laterally offset the plane of the tube portions within the shell 1 of any group of nested tubes from the plane of the tube openings 14b therefor; Thus `a space is provided between the pair of two groups of tubes communicating with one set of upper and lower compartments 7 and 8 in which a group of tubes connected with the opposite tube sheet may be interleaved.

In this manner more than one group of tubes 15 per compartment may be used without increasing the circumferential size of the head portions of the heat exchanger while at the same time achieving compartmentation.

Tube spacer means 17 may be provided in each of the heat exchangers shown in Figs. 1, 2, 3 and 4 in the usual manner within the shell 1 to maintain the proper or desired-spacing between'tubes and groups of` tubes nested and interleaved within the shell 1.

" A modified form of construction is shown in Fig. S and includes a shell 18, U-tubes 19, a tube sheet member 20, spaced parallel vertical partition walls 21, a central partition wall or member 22 and upper and lower cover plates 23 and 24 for the upper and lower compartments 25 and 26; The compartments 25 and 26 may be provided with tubeinlet and outlet ports similar to those in the heat exchangerillustrated in Figs. l, 2 and 3, a tube inlet port 27 being indicated in Fig. 5. 'In the construction shown in Fig. 5, the tube sheet 20 is curved in cross section in any direction so that the upper and lower compartments and 26 formed between the tube sheet 20 and cover plates 23 and 24 and the partition members 21 and 22 define chambers which are generally triangular in cross section as shown in Fig. 5.

A further modied form of construction is illustrated in Figs. 6 and 7 including a shell member 28, U-tubes 29, Va tube sheet 30, a shell extensionwall portion 31, and a head wall 32. Vertical partition walls 33 and a central partition wall 34 extend between the tube sheet 30 and head wall 32 generally in the same manner as the partition walls 5 and 6 in the construction shown in Figs. 1, 2 and 3. However, the modified construction enables the tube inlet and outlet ports, such -as the tube inlet port 35 shown in Fig. 6, to extend in a direction axially of the heat exchanger thereby conserving space laterally of the heat exchanger where the conditions of installation require'such space conservation.

The upper compartments 36 and lower compartments 37 formed between the tube sheet 30 and head wall 32 by vthe partition walls 33 and 34 may be individually closed by welding a diaphragm plate` 38 at the inner end of the opening 39 communicating with each of the upper and lower compartments 36 and 37 to provide a liquid-tight closure for the compartments. Back-up plates 40 may be mounted within the openings 39 and secured therein by bolts 41 which may be threaded into threaded openings cach lying half in-the head wall 32 and along the perimeter of the opening 39 and half in the outer surface of each back-up plate 40. The arrangement of the back-up plates 40 supports the loads imparted to the diaphragm plates 38 from the pressure contained within each compartment 36 and 37 and furnish a means of obtaining quicker access to the compartments for repairs in event of tube failure. -In the construction shown in Figs. 6 and 7, the bolts 41 and back-up plate 40 for any particular compartment may be quickly removed and the diaphragm plate 38 cut out to gain access to any particular compartment. A new diaphragm plate may be welded in place after the repairs are made. Such repairs are quicker than those required for cutting out and removing any of the cover plates 9 illustrated in Figs. 1, 2 and 3.

The construction illustrated in Fig. 8 is a modification of that shown in Figs. l, 2 and 3 and uses diaphragms and back-up plates for each upper and lower compartment rather than the welded cover plates 9 as shown in Figs. l, 2 and 3. In Fig. 8, individual diaphragm-plates 42 may be weldedin place, to close in a liquid-tight manner each of the upper or lower compartments such as the lower compartments 43, in a manner similar to the construction shown in Fig. 6. The back-up plates 44 may be bolted as at 45 and 45a to the vertical partition walls 46 and the shell extension wall 47. The bolts 45a secure the outer edges of the outer back-up plates to the shell extension wall 47, and the bolts 45 are threaded into halfthreaded openings provided in the abutted edges of adjacent back-up plates and secure the same to a common partition wall.

A still further modified form of construction is shown in Figs. 9 and l0 which is similar to that shown in Figs. l, 2 and 3 excepting that a much larger number of tubes are shown, and two groups of tubes communicate with most of the compartments while three rows of tubes communicatewith the compartments at either side of Ithe* heat exchanger. t

The construction in Figs. 9 and 10 includes la'shell 48, tube sheets 49 and 50, a shell extension wall 51, spaced vertical partition walls 52, a central partition wall 53 and cover plates 54 welded to thepartition walls 52 and 53 and the circumscribing shell extension wall 51.

A series of groups of nested tubes 55 are connected to openings 56 in the tube sheet 49, and another series of groups of tubes 57 are connected to tube openings 58 in the tube sheet 50. The tubes and 56 communicate as indicated with the various upper and lower compartments 59 and 60 formed by the partition walls 52 and 53, and these compartments vmay be provided with tube inlet ports 61 andtube outlet ports 62.

With thev arrangementshown in Figs. 9 and l0, two

groups of tubes communicate with each set of upper and lower compartments 59 and 60 except the outermost compartments where three groups of tubes communicate with such compartments. This arrangement permits interleaving of the groups of tubes because one of the groups of tubes communicating with one set of compartments adjacent the tube sheet 49 lies in the plane of a partition wall 52 extending from tube sheet 50; and one of the groups of tubes communicating with the compartments adjacent tube sheet 50 lies in the plane of a partition wall 52 extending from tube sheet 49. In this manner there is no loss vof space on the face of the tube sheets n providing the partition walls to obtain compartmentation.

' In each of the embodiments of the invention shown, compartmentation in the heat exchanger is achieved on the face of the tube sheet without sacrificing space for the partitions forming the compartments which would normally occur if all the U-tubes entered'a single tube sheet. Thus, a compact bundle of tubes may be provided within the shell with normal tube concentration throughout most of the length of the shell. As shown, the compartments may be provided with any one of a number of types of closure or cover means to contain the iiuid pressure existing in the compartments in a liquid-tight manner.

Other advantages achieved by the improved construction are that compartmentation is obtained without sacritice of space and yet the tube openings in the tube sheets may be `drilled in the normal way on the face of a iiat disc; and the U-tubes used are only formed with simple bends in a usual manner with many U-tubes in the Various tube groups identical in size and shape of U-bend.

The only disadvantage inherent in the improved-construction is that the unit cannot be operated in a vertical position if complete drainage of the tubes is essential and must under such conditions always be located in a horizontal position. However, this disadvantage is far outweighed by the provision of compartmentation in a compact space for a horizontally installed heat exchanger such as a steam generator.

Accordingly, the present invention provides a new construction of heat exchanger in which compartmentation .is provided without increasing space requirements for and weight of heat exchangers which must be continuously operated Without complete shutdown in event of tube failure and without requiring stand-by units,

In the foregoing description, certain terms have been used for brevity, clearness and. understanding,l but. no unnecessary limitations arel to'- be implied therefromibeyond the requirements'. of the prior art, because: such terms are used for descriptive purposes and are intended to be broadly construed.

Moreover, the embodiments of the improved construction illustrated and described herein are by way ofv ex` ample, and the scope of the present invention is not imited to thev exactA details of construction shown.

Having now described Ithe features, construction and principles of-'the invention, thev characteristics of the' new steam generator construction, and the advantageous, new and useful results provided; the* new and: useful discoveries, principles, parts, combinations, sub-combinations, structures andl arrangements, and mechanical equivalents obvious to those skilled in the art, are set forth in the appended claims.

I claim:

1. Heat exchanger construction including a shell, a tube sheet at each end of the shell; the outer face of each tube sheet being provided with spaced generally vertically extending partition walls, a center laterally extending partition' Wall and a circumscribingshell wall extension; said partition walls and extensionr being integral with the tube sheet and forming a series of upper and corresponding lower. compartments, eachcompartment havingV a separate outer cover plate secured to the partition walls and to the shell wall extension. forming the compartment, there being at least one row of tube openings formed in each tube sheet communicating with each compartment, at least one row of tubev openings communicating with each compartment l in one tube sheet being aligned with a vertical partition wall in the other tube sheet, a group of nested U-tubes connected' at one end to each row of tube openings communicating with each upper compartment and connected at theA other end to the corresponding row of tube openings communicating with the corresponding lower compartment, the nested U-tubes' in any group. extending from one tube sheet being disposed in the same plane, saidplane being oisetl from the plane of a corresponding group of U-tubes extending from the; other tubes'heet, andl each group of nested; U-tubes ony one tube sheet; extending to a location near. the; opposite -tube sheet and; between two groups of nested Utubes extending from saidv other tube sheet.

2. Heat exchanger construction including ashell, tube sheets at opposite ends. of the shell, walls integral with the tube sheet and forming a plurality of inlet and outlet head compartments on each tube Sheet, .the inlet compartments on eachV tube sheet being located side by side and parallel with each other, the outlet compartments on said tube sheet being similarly located and aligned with corresponding inlet compartments, eachI compartment having a separate outer cover plate secured to the walls forming the compartment, there being at least one row of tube openings formed in each tube sheetl communicating with each compartment, the rows of openings in one tube sheet beingoffset with respect to similar rows of openings inthe other tube sheet, a plurality of nested groups of U-tubes having inlet and outlet en'ds within the shell, the inlet ends of one group of U-tubes being connected to aligned openings communicating with an inlet compartment associated with one tube sheet, the outlet ends. of said one group of U-tubes being connected to aligned openings communicating with the corresponding outletV compartment associated with said one tube sheet, there being other groups of U-tubes similarly connected to the remaining inlet and outlet compartments associated with both tube sheets, theV nested U-tubes of any group extending from one tube sheet beingdisposed in a` plane parallel and adjacent to a similar group of nested U-tubes extending from 4the other` tube sheet, and each group ot nested U-tubes on one tube sheet extending to a location near the opposite tube sheet and between two groupsof nested U-tubes extendingI from said other tube sheet. l

3.. Heat exchanger construction including a shell, a tube sheet at each end of the shell, partition walls extending from the outer face of each tube sheet including spaced parallel verticalY partition walls and a central partition wall perpendicular to the spaced parallel partition walls` and forming parallel upper' and lower compartments on either side of the central partitiomwall, said partition walls being integral with the tube sheet,` head closure means for each compartment weldedto the parti-A tion walls, inlet means communicating withr'each upper compartment, outlet Ameans communicating `with each lower compartment, there being` at least oneprow of. tube openings formed in the tube sheet communicatingwith each compartment, at least one row of openings in one tube sheet communicating with each compartment being alignedwit-h a vertical partition wall extendingfrorn .the other `tube sheet, a U-tube extending from, each opening in a tube sheet communicating with` an upper compartment toy an opening in said tube sheetl communicating with aj corresponding lower compartment, the U-tubes extending lfrom the openings of4 a particular row communicating with one compartment being disposed in the same plane, said plane being offset from the plane of tubes extending from openings communicating. with a corresponding compartment in the other tube sheet, and each group of nested U-tubeson one tubev sheet extend'- ing to a location near the opposite tube. sheetv and be'- tween two groups. of nested U-tubes extending from said other. tube sheet..

References Cited inV thele of this` patent UNITED STATES PATENTS I K 686,313 Mann Nov. 12,/I 19,01 1,802,413 Engler Apr. 28, 193,1 1,879,453 Parent Sept. 27, 1932 2,065,708 Keirle Dec. 29, 1936 2,239,685 Moack Apr; 29,1941 2,337,624 Russell Dec. 28, 194,3 2,457,022 Yula Dec. 21, 1,948 2,743,089 Gardner et al. Apr. 24, 1956 FOREIGN PATENTS- 481,998 Germany sept. 4;. 1929 672,293 France Sept. 16, 1929

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