US2833526A - Steam generator head construction - Google Patents

Description

May 6 1958 P. s. OTTEN ETAT. 2,833,526

' STEAM GENERATOR READ CONSTRUCTION Filed June '22. 1955 4 sheets-sheet 1 1N VEN TORS By Dewey R'osI/ey f2 ATTORNEYS Pkwy s. 0mm

May 6,1958 P. s. o-rTEN ETAL 2,833,526

STEAM GENERATOR HEAD CONSTRUCTION Filed June 22, 1955 4 Sheets-Sheet 3 E25- mmm 1N VENToRs A5'. 0MM gi BY Dewegkosbe'y d ATTORNEYS May 6, 1958 P. s. o'rTEN Erm. 2,833,526

STEM GENERATOR HEAD CONSTRUCTION I Filed June I22, 1955 4 Sheets-Sheet 4 nd nc E INVENToRs Az'mRNEYs STEAM GENERATR HEAD lCONS'IRUCTIN Philip S. Otten, Canton, and Dewey R.

hio, assgnors to The @risconti-Russell Company, Massillon, Ohio, a corporation of Delaware Application June 22, 1955, 'Serial No. 517,124

3 Claims. (Cl. 257-221) Bosley, Massillon,

The present invention relates to heat exchangers. More particularly, it pertains to a steam generator heat exchanger having a compartmentalized tube sheet annularly disposed about the shell of the heat exchanger.

In any heat exchanger it is desirable to keep the size of the shell and tube iiuid heads .as small as possible, in order to keep the weight and the costof the parts which do not contribute -to heat transfer, at a minimum. In certain :applications there are further reasons for reducing vthe size of the equipment, such as lequipment within the shield area of a nuclear reactor, or in aircraft, or in seagoing vessels. In such instances, the size and mass ofotherequipment external to the heat exchanger may be determined by 'factors preventing Vreduction of size or mass so that any minimizing of the size and mass, of an associated iheat exchanger may constitute `Vthe vonly important reduction in size or mass of the equipment as a whole that can be made. l

In many processes using heat exchangers the `process can continue at decreased eiciency with the heat exchanger entirely out of the circuit in the event of leakage or failurefof the vheat exchanger. 'In other processes this is not possible and a failure of the heat exchanger Will interrupt the entire process unless a .stand-by heat exchanger is vprovided for such emergency. Where, however, a heat exchanger is a major item of equipment, considerations of economydo not permit kthe provision of a stand-by heat 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 stand-by exchanger for emergency purposes is not practicable.

One alternative to the provision of a .stand-by heat exchanger for emergency use is the compartmentation of the heat exchanger fluid streams directed through the heat exchanger. In many cases, compartmentation of lluid 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 effect, the compartmentation amounts to a multiplicity of stand-by 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 and a 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 Ilimitation 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 satises the requirements of space and weight limitation and critical processing. Ordinarily a compartmentalized heat exchanger occupies a certain minimum Vamount of space 4for a given application. Heretofore, compartmentation has been achieved with the l2,833,526 Patented May 6, 1958 sacrifice 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 theserdisadvantages and improves the overalldesign of conventional compartmentalized heat exchangers, and at the same time uses most eciently the space within a heat exchanger of minimum lateral dimension.

Further, in view of the foregoing, the present inven tion provides a tube sheet Aand a head portion associated therewith, which are adapted to cooperate withthe limited space requirements of the heat `exchanger itself as well as conlining the `inlet and outlet conduits of'theheat exchanger within the width vor diameter limitations of the heatexchanger.

Moreover, as a result ofthe 'new conguration ofthe tube sheet in order to maintain the overall diameter of the head portion ofthe heat exchanger at a minimum, the shape of lthehead portion and configuration of the 'heat exchange tubes havebeenimproved The head portion of the'present invention includes a plurality of compartments in order to facilitate continued operation of the -process where local failure occurs as was set forth above.

It is a primary object 'of 'this `invention to provide a lheat exchanger which meets certainy vdimensional requirements of diameters'or width without sacrificing operational and maintenance requirements.

Itis another objectof this invention to provide aheat 'exchangerhaving accessories attached thereto which are designed within the limits of the diameter of .the heat exchanger.

It is another object of this invention to provide aheat exchanger having-modified U-tube construction, the ends 'of which tubes are turned outwardly for connection with a tube sheet having a 'surface inclined tothe raxis of the heat exchanger. 4

It is another object of this invention .to provide a heat exchanger 'having a plurality of triangular shaped .head chambers or compartments which are disposed annnlarly around fthe yaxis `of Athe heat exchanger.

`It is anotherobject of thisinventionto provide a heat exchangerhaving a -plurality "of 'separate chambers or compartments whichare separatelyconnected to a plurality of bundles of heat exchangetubes and which compartments are separatelyconnectedto heat exchangeuid inlets. f

Itis another object of this invention to provide a heat exchanger having ahead portion which is annularly disposed thereto.

Itis another object ofthis Ainvention to provide a heat exchanger having a head portion 4annularly disposed .at one end thereof, the head portion l'having a .diameter slightly kgreater 'than that of ,the shell `of the heat exchanger. y

It is another objectof thislinvention itoprovide a heat exchanger having a verticalshe'll with a compartmentalized head portion `at one `end thereof.

Finally, itis an object of this invention to provide an improved heat exchange construction which obtains the foregoing desiderata @in 'a simple and leffective manner.

These and otherobjects and advantages vapparent to thoseskilledin the art fromrthefollowing*description and claims may ibe obtained, the :stated kresults achieved, and the described diculties fovercome, bythe zdiscoveries, principles, apparatus, parts, combinations, `subcombinations,rand.elements, which-comprise the present invention, the naturevof which is `settorth in :the .following general statement, vpreferred `embodiments of Which-illustrative of .the .best .modes .in which applicants have contemplated applying the principles-are set .forth in the following description, and which is particularly and distinctly pointed out and set forth in the appended claims forming part hereof.

The nature of the improved apparatus of the present invention may be stated in general terms as including, an elongated cylindrical shell portion having a plurality of U-shaped heat exchange tubes extending therethrough, the tubes having opposite ends connected to a tube sheet at one end of the shell portion, the tube sheet having the surface of a truncated cone, an even number of radial partitions extending outwardly from the tube sheet, a

cover member surrounding the outer extremities ofthe partitions, the tube sheet, the partitions, and the cylindrical member forming a plurality of triangularly shaped compartments therebetween, the tube sheet having a plurality of rows of `tube-receiving openings, each row of openings communicating with one of the compartments, the compartments having uid inlet ports extending therefrom, a uid conduit extending from each inlet port to `a uid source, the conduits extending from the compartments being confined between opposite limits `of the width of the heat exchanger, the U-shaped tubes having one end connected to the tubefreceiving openings of one compartment and having the other ends connected to tube-receiving openings of `a compartment opposite thereto, and the tubes being in parallel planes.

By way of example, the preferred embodiments of the apparatus of the present invention are illustrated in the accompanying drawings forming part hereof,` and in which similar numerals refer to similar parts throughout the various figures of the drawings:

Fig. 1 is an elevational view of the heat exchanger having` cut away portions showing the configuration of the heat exchange tubes, the tube sheet and the head portion;

Fig. 2 is a bottom view taken on the line 2-2 of Fig. 1;

Fig. 3 is a horizontal sectional view taken on line 3-3 of Fig. 1;

Fig. 4 is an enlarged, fragmentary, vertical sectional view, partly in elevation, showing another embodiment of the invention;

Fig. 5 is a horizontal sectional view taken online 5--5 of Fig. 4; and

Fig.` 6 is a horizontal view, taken on the line 6-6 of Fig. 1, showing a portion of the tubes in the plan view and another portion in sectional view.

In Fig. 1 a heat exchanger is generally indicated at 1.

It consists of a shell portion 2, a plurality of heat exchange tubes 3, a tube sheet 4 and a head portion 5.

The shell portion 2 is a vertical cylindrical member having a dome-shaped cap or cover 6 at the top and a cap 6a at the bottom of the heat exchanger. The caps or covers 6 and 6a are secured in a liqudtight manner, preferably by welds at 7 and 7a. At the top of the domeshaped cap or cover 6 is a pair of fluid ports 8 and 9 which serve as steam outlets inasmuch as the particular heat exchanger 1 shown is a steam generator.

Near the top of the shell portion 2 and below the cover 6 is a pair of downcomers 10 and 11 which serve as liquid inlets for the shell lportion 2. Associated with the down comers 10 and 11, which are oppositely disposed with respect to each other, is a cylindrical sleeve 12 within the shell portion 2 having an outer diameter slightly less than the inner diameter of the shell portion, thereby providing an annular space 13 therebetween. y'I'he sleeve 12 extends through the greater part of the length of the shell portion 2 and is secured thereto at its upper end in a liquid-tight manner, preferably by an annular we1d 14 situated slightly below the weld 7. The lower end of the sleeve 12 is open at 15 so that liquid entering the shell portion 2 through the downcomers `10 and 11 lls the annular space 13. In this manner the interior of the shell portion is encased within an ambient layer of uid adjacent the inner surface of the shell portion 2 which layer moves downwardly to the` lower end of the sleeve where it escapes into the shell portion proper at 15 and where it comes into intimate contact with the heat exchange tubes 3 within the shell portion 2. As a result of the heat exchange which occurs between tubes 3 and said iluid, the fluid is converted into steam under higher pressure than the pressure of the fluid entering the downcomers 10 and 11. Thus, thev sleeve 12 serves the purpose of preventing the steam from interfering with the inflow ofthe iiuid through the downcomers 10 and 11 and directs the steam upwardly to the uid outlets 8 and 9.

The tubes 3 are substantially U-shaped and are disposed in bundles or nested groups generally indicated at 3a in l, 4 and 6. Each bundle 3a of tubes 3 is disposed in a piane passing through a chord of a circle deiined by the shell 2 of the heat exchanger. All of the bundles 3a are parallel to each other, as shown in Fig. 6.

The bundles 3a of tubes 3 consist of a plurality of tubes in varying numbers depending upon the distance of a particular bundle from the shell 2. Each tube 3 has an upper bent portion 16 (Fig. l) which is concentrically disposed with respect to similar portions of other tubes in the same bundle. The innermost tubes 3 have bent portions 16 with smaller bent portions than the outer tubes. Lower ends 17 of each tube 3 are connected to tube-receiving openings 18 in the tube sheet 4 in u liquidtight manner and extend radially therefrom. It is understood that the opposite ends of each tube 3 are similar, as shown for the ends 17 in Fig. l. The tube-receiving openings 18 are aligned and extend through the tube sheet 4 to the head portion 5.

The tube sheet 4 has the shape of a truncated cone. As shown in Figs. l and 4, it is an inverted cone. The upper end of the structure comprising the'tube sheet 4 and the head portion 5 is secured to the lower end of the shell 2 by a weld 19 and the lower end of the same structure is welded to the lower dome-shaped cap 6a by the weld 7a. The inner surface of the tube sheet 4 is inclined to the axis of the shell 2 and the lower ends 17 of the tubes 3 extend perpendicular from their respective openings 18 in the tube sheet. The diameter of the tube sheet 4 yat the upper end is greater than that at the lower end near the dome-shaped cap 6a.

Surroundingthe outer surface of the tube sheet 4 is the head portion 5 of the heat exchanger. The head portion 5 is compartmentalized and includes a number of compartments or chambers 20 with which the tube open-4 ings 18 communicate. The compartments 20 are separated by radially extending partitions or lands Z1 (Fig. 3) which extend from the upper end of the tube sheet 4 to the lower end thereof and which are triangular in vertical cross section, whereby each compartment 2l) is likewise triangular in vertical cross section. Thus, the lower ends of the compartments 20 have a larger volume than the upper ends.

The outer side of each compartment 20 is covered with a cover member 22 extending between adjacent partitions 21 to which the vertical edges of the cover members 22 are secured in a liquid-tight manner, such asby welds 23, as shown in Fig. 3. Across the lower end of the cornpartment 20 is a closure member 24, as shown in Fig. l, which member is likewise secured to the lower end of the tube sheet 4 and the cover members 22 in a liquidtight manner, such as by welds 25 and 26, respectively.

The upper portion of Fig. 6 shows the tubes 3 in plan view with only the bent portion 16 of the uppermost tube shown. Below each bent portion 16 are a number of concentrically disposed bent portions of similar tubes 3, as shown in Fig. l.

In addition, the upper portion of Fig. 6 shows the opposite lower ends 17 of the tubes 3 extending radially from their respective openings 18 in the tube sheet 4 (Figs. l and 3). As shown more particularly in Fig. 3, there is a pair of tubes 3 extending from each compartasaasae ment through the tube sheet 4. Thus, for eachacompartment 20 there are two rows of tube-receiving `openings 18. For 'this reason, 'the bent portions '17 of the tubes 3 extend from the shell in pairs. However, it is understood that any other number of rows of openings 18 may be provided for each compartment 20 in the tube sheet 4, such as one or three rows.

In the lower 'half of Fig. 6, the tubes are shown in cross section in a plane 'below the bent portions 16. `The vertical portions of the tubes 3 have axes disposed on intersections of parallel lines, such as the grid shown on the left side of the lower half of Fig. 6. It is understood that the left side is occupied by tubes 3 similar to those shown in the right side of Fig. 6. That is, each tube 3 in the lower right side of Fig. -6 extends .to a similarly disposed portion ,of the tube in the lower left side.

With the axes of the tubes 3 disposed in alignment both horizontally and vertically, as shown by the grid, tube bundles 3a are formed in parallel planes. A particular bundle may be composed of tubes extending from two or more rows of openings 18 in the tube ,sheet 4. Moreover, the tubes 3 in a .given bundle may extend from a number 4of .compartments 20, .the tubes being bent at their lower .ends to enter-a particular bundle 3a. -Like the tubes 3 in the upper portion .of Fig. 6, the tubes in the lower portion have bent portions A16 which are concentrically disposed with respect to each other at the upper portion of the shell 2.

Generally, the tubes 3 nearer the shell 2 `have bent portions 16 of greater radii `than the tubes nearer the center of the shell 2. For example, the particular tube ends .17a and `17h (Fig. 6) are opposite ends of the same tube 3. Likewise, the particular tube ends 17a and y17a' are opposite ends of another tube 3.

As was set forth above, the compartments 20 are equally disposed around the tube sheet 4 which is shaped like an inverted truncated cone, the upper end of the tube sheet having a greater diameter than the lower end. The compartments 20 on the right half side ofthe heat exchanger 1, as shown in the drawings, constitute the entry side of the heat exchange liquid flowing through the tubes 3, and the compartments 20 on vthe left half of the drawing constitute the outgoing side ofthe liquid. In Figs. l, 2 and 3, each compartment 20 is provided with a liquid conduit 27 having one end communicating with the compartment, and having .another end communicating with a liquid header or manifold 2S. Similar members on Ythe opposite side of the heat exchanger are identified as conduits `27a' and header 28a. 27 on the right side of the heat exchanger 1 deliver `the liquid to the tubes 3, while the 'conduits 27a lcarry the liquid away from the tubes to a similar header 28a.v

In Fig. 2, the general configuration of the conduits 27 and 27a is shown. All of the conduits 27 and 27a are confined within two opposite sides of the heat exchanger 1. Likewise, the length .of the headers 2S and 28a are limited within the same opposite sides. The conduits 27 and 27a extend from two rows of openings 29 and 29a in the lower side of the headers 28 and 28a, respectively, and are bent in such a manner that the conduits from the outer rows 29 and 29a are connected to compartments 20 at a lower level than the conduits extending from the inner row 29 and 29a. That is, the conduits 27 and 27a enter their respective compartments 20 at different levels, as shown in Fig. l. Each level is near the lower larger end of the compartments. Further, in order to provide conduits to six compartments 20 nearest the two opposite sides within which the conduits and headers are confined, the conduits 27 and 27a, are connected to their respective compartments 20 through the closure member 24, as indicated at 30 and 30a in Fig. 3 on opposite sides of the heat exchanger 1.

In Fig. 4 another embodiment of the heat exchanger is shown. In this embodiment liquid conduits 31 extend- The conduits y ing between a header 28 (not shown in Fig. 4, but similar to that of Fig. l) and the compartments 20 (similar to conduits 27 in Fig. l) are connected to their respective compartments 20 through a `closure member 32 similar to closure member 24 in Fig. l. This construction leaves youter edges of the partitions or lands 21 by means of a number of bolts 34 (Fig. 5). Each cover member 33 includes a diaphragm member 35 adjacent the inner side of the members 33. The diaphragms 35 `are ,secured in place by means of Vperipheral welds 36. In this manner, each diaphragm 35 after being secured in place is covered with V.the cover member 33 which serves asa back-up member for the assembly.

The purpose of the construction in the second embodiment is -to provide a more .easily removable cover 33 for each compartment 29 whereby separate entry may be had thereto and to the individual tubes .3 when necessary for repair and maintenance purposes. It is .easier to remove and replace the cover member 33, the bolts 34 and the diaphragm 35 with the relatively small weld 35, than it is to remove the cover `22 (Fig. 1) having a relatively heavy -weld 26 and having the tubes 27 secured thereto. In both embodiments of this invention the conduits 27, 27a and 31 are connected to the compartments 2t) of the head portion at the lower end thereof where the compartments have the greater volume to accommodate the iiow of the uid upon entering and leaving the tubes 3.

In operation the liquid to be cooled enters the header 2S and moves through the conduits 27 into the liquid in let compartments 20 from which the liquid passes through the heat exchange tubes 3 in which the liquid passes through the shell 2 of the yheat exchanger 1. From the tubes 3 the liquid exits through outlet compartment 20 similar to inlet compartments 2.0 on the opposite side of the heat exchanger, and then through the outgoing conduits 27a to the header 28a. At the same time the liquid to be heated, namely water, enters the heat exchanger 1 through the downcomers 10 and 11, and passes downwardly between the shell 2 and the sleeve 12 to the lower end of the sleeve where it enters the interior of the heat exchanger and tlls the space between the tube bundles 3a. As the water absorbs heat from the tubes 3, it rises to the top of the shell and is converted to steam in which form it leaves the heat exchanger 1 through the fluid outlets 8 and 9.

The foregoing description provides a heat exchanger having an optimum size lwithout sacrificing operational and maintenance requirements. The maximum diameter of the .heat exchanger is that portion which includes the tube sheet and the compartmentalized head portion around the tube sheet. By providing a conically-shaped tube sheet, the compartments of the head portion yhave triangular shape with the fluid inlet and outlet conduits to auxiliary equipment being connected at the larger ends of each compartment. Thus, the triangularl shape of the compartments makes possible not only the accommodation of the ambient fluids without a reduction of etiiciency, but also provides a tube sheet together with a head portion which is annularly disposed with regard to the longitudinal axis of the heat exchanger. Each head compartment is thereby accessible for local repairs. At the same time, the combined tube sheet and head portion occupy only a relatively small increased diameter over that of the shell portion.

The foregoing construction of the tube sheet and com partmentalized head portion affords the opportunity of using prescribed floor space of minimum dimensions in which auxiliary conduits leading to and extending from the heat exchanger are confined within two opposite parallel planes spaced by a distance equal to the maximum diameter of the heat exchanger. These features solve probindicated.

In the foregoing description, certain terms have been used for brevity, clearness, and understanding, but no unnecessary limitations are to be implied therefrom beyondthe requirements of the prior art; because such words are used for descriptive purposes herein and not for the purpose of limitation and are intended to be broadly construed.

Moreover, the embodiments of the improved construction illustrated and described herein are by way of example, and the scope of the present inventionis not limited to the exact details of construction shown.

Having nowdescribed `the features, construction and principlesof invention, the characteristics of the new steam generator head construction and the advantageous, new .and useful results provided; the new and useful discoveries, principles, elements, combinations, subcombinations, `structures and arrangements and mechanical equiva- L lents obvious to those skilled in ,the art are set forth in the appended claims.

We claim:

1. Heat exchanger construction including a shell, a tube sheet at one end of the shell having the shape of a truncated cone with the larger end adjacent andconnected to the shell and the smaller end forming an end opening for the shell, `cover means for said opening at the smaller end of the truncated conical tube sheet, aplurality of partitions extending radially from the tube sheet, the parf titions forming a series of compartments generally radial- Vly enveloping the tube sheet outside of said cover means, compartment cover means for each compartment extending between the, outer edges of adjacent partitions, the tube sheet having a plurality of tube openings communieating with each compartment, each compartment having a conduit connected thereto, the compartments including a plurality of inlet compartments on one side of the heat exchanger and a plurality of outlet compartments on the other side, each inlet compartment having a corresponding outletl compartment circumferentially spaced therefrom, and a bundle of U-tubes extending into the shell and connected at opposite ends to the tube openings of corresponding inlet and outlet compartments.

2. Heat exchanger construction including a shell, a tube sheet at one end of the shell having the shape of a truncated cone with theflarger end adjacent and connected to the shell andthe smaller end forming an end opening for the shell, cover means for `said opening at the smaller end of the truncated conical tube sheet, a plurality of'partitions extending radially outwardly from the tube sheet, the partitions forming a series of compartments generally radially enveloping the tube sheet outside of said cover means, the compartments each having a triangular shape in radial cross section with the side radially outside the tube sheet parallel to the axis of the shell, compartment cover means for each compartment extending between Athe outer edges of adjacent partitions and defining said parallel side of such compartment, the tube sheet having ya plurality ofl tube openings communicating with each compartment, each compartment having a conduit connected thereto, the compartments including a plurality of` inlet .compartments on one side of the heat exchanger and a plurality of outlet compartments on the other side, each inlet compartment having a corresponding outlet compartment circumferentially spaced therefrom, and a bundle of U-tubes extending into the shell and connected at opposite `ends to the tube openings of corresponding inlet and outlet compartments.

3. Heat exchanger construction including a vertical cylindrical shell, a tube sheet at one of the shell having the shape of a truncated cone with the larger end ad'- jacent and connected to the shell and the smaller end forming the lower end opening for the shell, cover means for said opening at the smaller end of the truncated conical tube sheet, a plurality of partitions extending radially outwardly from the tube sheet, the partitions forming a series of compartments generally radially enveloping the tube sheet outside of said cover means, each compartment having a right triangular shape in radial cross section with the outer surface of the tube sheet forming the hypotenuse and the side radially outside the tube sheet longer than the third side of the triangle and parallel to the axis of the shell, compartment cover means for each compartment extending between the outer edges of adjacent partitions and defining said parallel side of such compartment, the tube sheet having a plurality of rows of tube openings, at least one row'communicating with each compartment, a conduit connected to and extending Afrom each compartment near the right angle,lthe conduits being located within a zone bounded on two sides by planes tangent to the cylindrical portion of the heat exchanger of maximum diameter, a plurality of U-tubes, the U-tubes being nested in bundles in the shell with the axes of the tubes in each bundle lying in a plane, the bundles of tubes being parallel, the opposite ends of each tube being connected radially to circumferentially spaced compartments, the compartments including a plurality of inlet compartments on one side of the heat exchanger and a plurality of outlet cornpartments on the other side, each inlet compartment having a corresponding outlet compartment circumferentially spaced therefrom, and the opposite end connections of U- tubes to spaced compartments being with corresponding inlet and outlet compartments.

References Cited in the le of this patent UNITED STATES PATENTS `244,039 Davis July 12, 1881 575,207 Brown Jan. 12, 1897 686,313 Mann Nov. 12, 1901 1,782,430 Kelly et al Nov. 25, 1930 2,643,862 -Stelling g June 30, 1953 FOREIGN PATENTS 5,391, Great Britain of 1986

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