US2868180A - Heat exchange apparatus - Google Patents

Description

Jan. 13, 1959 J. F. THuNsTRoM 2,868,180

HEAT EXCHANGE APPARATUS Filed Aug. 11, 1955 4 Sheets-Sheet 1 INVENTOR JEH/v F'HuA/Sr/MM BE uw ATTORNEY Jan. 13, 1959 J. F. THUNSTROM y 2,868,180

HEAT EXCHANGE APPARATUS Filed'Aug. 11, 1955v l 4 Sheets-Sheet 2 INVENTOR .fof/N F Tf/u/vsrfPoM BYU. Aww/8 ATTO R N EY Jan. 13, 1959 k.1. F. THUNSTROM Filed Aug. l1, 1955 HEAT EXCHANGE APPARATUS l /Z l /214 L o jm je Y x f//l Il /4 50 A .l 19 emr@ INVENTOR fa/wv E MwST/mu BY C. 67.

ATTORNEY Jan. 13, 1959 J. F. THUNSTROM HEAT EXCHANGE APPARATUS 4 Sheets-Sheet 4 Filed Aug. ll, 1955 INVENToR Ja//v F.' THU/vs T/Pa/v o ww ATTORNEY metallic member to the tube wall..

ltubes.

HEAT GE APPARATUS John F. Thunstrom, 'N ew York, N. Y., assigner to Foster Wheeler Corporation, New York, N. Y., a corporation of New York Application August 11, 1955, Serial No. 527,678

4 Claims.v (Cl. 122-478) This invention relates to iluid heat exchange apparatus and more particularly to'tubular support arrangements for such apparatus. 1n liuid heat exchange apparatus, as for example, vapor` generators, supports for uid conducting tubular members have always presented considerable p maintenance problems, one of the reasons beingthe poor grade of present day fuels. This is especially true in the case of superheaters. Numerous types of supports have been proposed but the majority depend upon sometype of metallic member other than the tubing to support the superheater elements. The supports have corroded and` failed repeatedly after only short service because the cooling of thermembers in the hot gas zone is limited to the low heat transfer atiorded by conduction through the The problems due to the corrosion of the members have been accentuated by the extreme difhculty experienced in the complicated and tedious procedure of replacing the members.

` The present invention contemplates a novel supportfo lluid conducting tubular members in fluid heat exchange apparatus and particularly to superheaterstherein. The support is achieved by using only the boiler and superheater tubes, and a portion of the boiler tubes and the superheater tubes are shaped to provide the sole means of supporting and spacing the superheater tubes. Spacing of the superheater tubes is accomplished byalternating a row of superheater tubes between specially bent boiler The specially bent rows of boiler tubes immediately precede and follow the superheater in the direction of gas flow. A minimum clearance transverse of the direction of gas flow is provided between the superheater United States Patent O y 2,868,180 Patented Jain. 13, 1959 ICC Referring now to the drawings and more particularly toFig. 1 thereof wherein one embodiment of the present invention is clearly illustrated, the numeral 11 generally designates a vapor generator which comprises a setting 12 and 'a roof portion 12A. The vapor generator 11 is illustrated for purposes of explanation as a marine vapor generator but it is to be understood that: the subject invention is readily applicable to other types of vapor generators. A furnace, or combustion chamber 13, is provided in setting 12 and the Walls of the combustion chamber are lined with boiler tubes 14. The upper ends of boiler tubes 14, along a rear wall 15, are connected to an inclined header 16 (shown in broken lines) adjacent roof portion 12A, which header in turn communicates `with a vapor and liquid vessel 17 in the upper portion of the setting by means (not shown); the boiler tubes 14, along a side wall 18, thence extending parallel to roof portion 12A and being directly connected to vessel 17. The `lower ends of boiler tubes 14 along rear wall 15 p are connected to a header 19 disposed at the bottom of setting 12 and the header, in turn, is connectedto a water header 19A by oor tubes (not shown) to receive liquid therefrom. A header A20, also connected by the floor tubes (not shown) to header 19A, is disposed at the bottom of side wall 18 and is connected to the boiler tubes along said wall.

elements and boiler tubes to hold theelements in proper `location and the clearance is such that it will permit the superheater elements to expand at a rate other than that of the boiler spacer tubes.

AThe foregoing advantages of the present invention will of the novel support means of Fig. 1;

Fig. 3 is a top plan view of the support of Fig. 2;

Fig. 4 is a sectional view taken along the line 4-4 of Y Fig. 2;

Fig. 5 is a fragmentary view, in elevation, of the vapor generator of Fig. l but discloses a second embodi- V ment of the present invention;

Fig.`6 is a fragmentary view, in elevation, of the support of Fig. 5;

Fig. 7 is a top plan view of the support of Fig. 5; and Fig. 8 is a sectional View taken along the line 8--8 of Fig. 6. r

`3f?. and a superheater outlet header 33.

A plurality of substantially vertical, but slightly inclined, boiler screen tubes 21 are arranged on the side of combustion chamber 13 opposite side wall 18 and extend from the front Wall -of setting 12 to "rear wall 15. Tubes 21 are arranged in three parallel rows 22, 23 and 24, respectively; the tubes in row 22 being closest to the furnace. The upper ends of tubes 21 are connected to the lower portion of vapor and liquid drum 17 while the lower ends of the tubes are connected `to water header 19A. Header19A receives water through conduits 2S (one shown) connected to a water drum 26 which, in turn, receives water from vapor and liquid vessel 17 by a`pluralityvof convection tubes 27 and downcomers not shown. Convection tubes 27 are spaced from tubes 21 yand substantially parallel therewith and are connected attheir upper ends with vessel 17 and at their lower ends to water drum 26. Tubes 27, as do tubes 21, extend from the front wall (not shown) to the rear wall 15. Two rows 28 and 29 of tubes 27 are bent at their upper ends differently from the remaining tubes 27, for a purpose to be brought out presently.

A` superheater 30 is disposed in the space between tubes 21 of row 24 and tubes 27 of row 28 and comprises superheater tubes or elements 31. Superheater l tubes 31 are `arranged substantially vertically but slightly inclined and the ends of each tube are arranged adjacent each other for connection to a superheater inlet header Each superheater tube 31 comprises a pair of legs 34 and 35 which are disposed substantially parallel with each other. The intermediate portion of each tube 31 extends substantially transversely of the legs and is arcuate-shaped or in the form of a loop. Leg 34 of superheater tube 31 is substantially straight throughout its entire length and merges into the arcuate intermediate portion, while leg 35 i-s Substantially straight to a point vertically below the point where leg y34 merges into the arcuate portion; leg 354 thereafter is inclined toward opposite leg 3d to merge into the arcuateportion adjacent the last vmentioned point; As indicated in Figs. 2 to 4 superheater tubes 31 are arranged in parallel planes which are horizontally spaced.` Tubes 31 are arranged in a predetermined pattern wherein the tube in one plane is rotated o from the position of the superheater tubes in the `preceding and succeeding planes (Fig. 2).

Additional `superheating tubes 31 are arranged within the space en- 4superheater tubes (Fig. 4 2).

vwater is formed which ows into'drum 17'.

leach other below the point'where'ithe vlegs are inclined. Each outermost Vs'uperheater tube 31 has Vprovided coplanar'the'rewith a tube l21 of rows 23 or 24 and a`tube n27 of rows 28 or 29. As seen in Fig. 3, "the first plane containing superheater tubes 31 has 'the outermost tube engaged by a boiler tube '21 vin row 24, which boiler vtube. then extends parallel totheinclinefd portion of the Leg 34 of the outermost superheater tube 31 in 'the last-mentioned'plane is engaged by a tube 27 in'row 29 fand by reason of the foregoing, the superheatertubes l31 in each plane are supported. In the next followingplane leg 34 of the the superheater tubes 31 to someextent, yand. on both sides of the nested tubes, toet/hereby prevent lateral lmove- .ment of the latter. In this manner, motion ofthe lsuperheater tubes 31 is constrained-in all-directions except lengthwise along the superheater tubes to permit thermal expansion of the latter. Furthermore, the superheater .tubes are bent in a manner that they bear upon the tubes 21 and 27 for a short distance to -provide for the transmission of a portion of the load to the latter.

l, A flue 38 is formed in the upper portion of the setting 12 for discharging combustion gases from the latter and an economizer 39 is disposed in ll-ue 38. y

.ln operation, combustion gasesformed in combustion chamber 13 pass over tubes 21 and inheat exchange relationship therewith thence over superheater tubes 31 and convection tubes'27. The combustion gases' then liow outot the setting through ue 38 and in heat exchange relationship with economizer 39. The water in drum 17 flows downwardly through the downcomers (not shown) and through some ofthe tubes 27 into water drum 26. From drum l26aportion of the water ows into the remaining tubes 27 where a'steam and water `mixture is formed which flows into drum 17. Water from drum 26 also flows into header 19A through conduits l25 and a portion ofthe water Vthereafter flows upwardly into tubes 21 where a mixture of steam and Water'in header v19A also flo-ws through the floor tubes (not shown) for collection in headers' 19 and 20 whence the water flows upwardly in boiler tubes 14 for entry into header 16 and drum 17vas a steam and waterl mixture. The steam collected in vessel 17 Ai-s then conducted'by means (not shown) to superheater inletheader 32, whence the steam passes through the superheater tubes 31 where the steam is superheated, and the superheated steam. is collected in outlet header 33. vFrom outlet header 33 the steam is conducted to-steam utilization apparatus (not shown).

Figs. to 8 illustrate a second embodiment of the V present invention and differs from the irst embodiment yin that the second embodiment provides'for twosetsof `nested su-perheater tubes in each'parallel plane. Vthe screen boiler tubes 21 and convection tubes 27 of Since "prises superheater tubes'43 and which"`are coplanar nd' pairs of the'latter are arrangedein'horizontally spaced arallelfplanes. In the tirstpla'riecontaining'bothj super- 4. tube 43 includes a pair of substantially parallel legs 45 and '46 vwhil'e 'superhe'ater tube 44 includes a pair 'of substantially parallel legs 1,47 and 48. The end of leg 45 of superheater tubes 43 is secured to a superheater inlet header 49 while the end of leg 46 is secured to an intermediate superheater header 50 arranged above header 49 is shown in-Fig 5. The end of leg 47 of superheater tube 44 is 4secured to intermediate superheater header 50, while Vthe end`of Lleg 48 is secured to an outlet superheater 'header 51. The intermediate .portions -of vsuperheater tubes '43 and "44 -are substantially in the form of loops, or arcuate shaped, which extend substantially transversely of their respective legs. Legs 45 and 46 of superheater tubes "43 are substantially straight throughout their 'respective 'lengths except adjacent the intermediate portion where leg 45 is bent into engagement with tube 21 of row 23 (Figs. 5 and 6). Legs 47 and 48 of superheater tubes 44 are substantially straight to a point vertically below the point where leg 4S isbentinto engagement with the tube l21. Legs 47 and 48 of superheater tubes 44 are inclined 'from the first-mentioned point toward superheater tube 43 and in engagement with thellatter as `seen in Fig. 6. In the first-mentioned plane superheater tube "43 is Aprovided with an inner nested tube which is similarly shaped and in engagement withv tube 43adjacent the point'where the latter engages'tube 21. A portion of leg A48 of superheater tube 44 engages convection tube 27 of row 28 adjacent the second mentioned point. `An inner `superheater tube is arranged within the lspace encompassed by superheater tube 44 and is shaped in substantially the same manner as the latter. The legsof theinner superhe'ater tubes engage and bear on the legs 447 and 48 of the outer superheate-r tube 44 adjacent the point where tube 44 engages lconvectiontube 27 of row28. Tube'27 of row 28 is inclined from the mentioned point of engagement to extend substantially parallel to the upper portions oflegs 47 and 48 for a short distance and then substantially vertically for connection with vessel 17. Tubes 43 and 44rare `arranged in a pattern wherein the tubes in one plane, other than' the iirst'mentioned plane, are rotated from the positions in the preceding and succeeding planes so as to provide a substantially criss cross pattern. Thus, in the next succeeding plane the ends of leg 45fot superheatertubes 43 are connected to outlet header 51 and the ends of leg 46 are connected to intermediate header 50. ln'likemanner, the ends of leg 47 are connected to intermediate header 50 and the ends of leg 48 are connected to inlet header 49. 'In `order to restrain lateral movement of the superheater tubes 43 and 44 a pair of ltubes 21 and 27 of rows 24 vand 28, respectively, are arrangedon each side of planes containing the superheater tubes 43 and 44.

In the foregoing construction a portion of 'theloadof superheater tubes v43 and 44 isitransmitted to tubes, 21`

and 27 and in addition'aportion of the load 'of the inner nested tubular members is transmitted through tubes 43 and 44 to the tubes 21 and 27.

The operation of the second embodiment of the present invention in a vapor generator is identical with that of the rst embodiment andthe combustion gasesv from the combustion chamber pass first in contact with tubes '21 of rows 23 and 24, thence in contact with superheater tubes 43 and 44, whence the gases pass in contact with have beenillustratedand 'described in detail,i it is to be "expressly understood that the invention isnotfli'rnited thereto. Various changes can be made in the design' and arrangement of the parts without departing from the spirit and scope of the invention as the same will now be under stood-by those skilled in the art.

What is claimed is:

1. In a tubular arrangement for fluid heat exchangers, a substantially vertical first fluid conducting tubular member having iixed ends adjacent to one another and hav ing a pair of coplanar legs substantially parallel with each other, one of said legs being substantially straight and merging into an upper loop and intermediate portion while the second leg is substantially straight and to a point vertically below the point on said one leg where the latter merges into the loop portion, said second leg being inclined toward said one leg from the first-mentioned point and merging into the other side of the loop portion, a second vertical iiuid conducting tubular member disposed along each leg of said iirst tubular member and coplanar therewith, the second tubular member along said one leg being spaced from the latter except adjacent the secondmentioned point where it extends toward and in engagement with said one leg, the second tubular member along said second leg being spaced from the latter except adjacent the first-mentioned point where it engages said second leg, said last-mentioned second tubular member thereafter being inclined and arranged parallel to the inclined portion of said second leg, and a pair of substantially vertical third fluid conducting tubular members arranged in parallel planes, one of said third tubular members being on one side of the plane containing the first and the second uid conducting tubular members and the other third tubular member being on the other side of said plane for preventing lateral movement of said first fluid conducting tubular member transversely of said third fluid conducting tubular members.

2. In a tubular arrangement for fluid heat exchange apparatus, a plurality of horizontally spaced and substantially vertical first fluid conducting tubular members each of which have xed ends adjacent to one another, each of said tirst tubular members having a pair of coplanar legs substantially parallel with each other, one of said legs being substantially straight and merging into an upper loop and intermediate portion while the second leg is substantially straight to a point vertically below the point on said one leg where the latter merges into the loop portion, said second leg being inclined toward said one leg from the first-mentioned point and merging into the other side of the loop portion, said iirst tubular members being arranged so that successive tubular members are rotated 180 from the preceding tubular members, and a second vertical uid conducting tubular member disposed along each leg of said rst tubular member and coplanar therewith, the second tubular member along said one leg of the iirst tubular member being spaced from the latter except adjacent the second mentioned point where it extends toward and in engagement with said one leg, the second tubular member along said second leg being spaced from the latter except adjacent the tirst-mentioned point where it engages said second leg, said last-mentioned second tubular member thereafter being inclined and arranged parallel to the inclined portion of said second leg and positioned adjacent the loop portions of the preceding and succeeding lirst tubular members to prevent lateral movement of the latter transversely of the inclined portion of the second tubular member.

3. The tubular arrangement set forth in claim 2 wherein additional vertical first fluid conducting tubular members are disposed coplanar with the iirst vertical tubular members and in the space encompassed by the latter as to be nested therein, said additional tubular members having portions corresponding to the first and the second mentioned points on said legs engaging each other, and the outermost additional first tubular member engaging the first tubular member at the portions Where the latter engage the second tubular members.

4. .ln a tubular arrangement for Huid heat exchange apparatus, a plurality of pairs of substantially vertical tirst tluid conducting tubular members, each pair, of tubular members being arranged in horizontally spaced and parallel planes, each of said tubular members having fixed ends adjacent to each other and including a pair of substantially parallel legs, one of said pair of tubular members having the legs thereof substantially straight throughout their lengths except at the upper part where the legs merge into a loop portion, the other of said pair of tubular members having legs substantially straight to a point vertically below the point where the legs of said one tubular member merges into the loop portion, the legs of said other tubular member being bent from the irst-mentioned point and inclined toward said one tubular member to merge into a loop portion, the portion ofthe tubular member adjacent said last-mentioned loop portion engaging said one tubular member adjacent the loop portion of the latter, said pairs of tubular members being arranged so that successive pairs of tubular members are rotated from the preceding tubular member, and a second Vertical liuid conducting tubular member disposed along one leg of each of the pairs of first tubular members and coplanar therewithJ the second tubular member along said one leg of said one lirst tubular member being spaced from the latter except adjacent the second mentioned point Where the second tubular member engages said one leg of said one iirst tubular member, the second tubular members along the one leg of said other iirst tubular member being spaced from the latter except adjacent the iirst mentioned point where they engage the last-mentioned leg, said last-mentioned tubular members thereafter being inclined and arranged parallel to the inclined leg portions of said other iirst tubular member and preventing lateral movement of the preceding and succeeding one iirst tubular member.

References Cited in the file of this patent UNITED STATES PATENTS 2,415,068 Andrew Feb. 4, 1947 2,685,279 Caracristi Aug. 3, 1951 FOREIGN PATENTS 121,581 Sweden May 4, 1948

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