US2639125A - Fluid to fluid heat exchanger - Google Patents

Description

May 19, 1953 G. B. R. FEILDEN ETAL. 2,639,125

FLUID TO FLUID HEAT EXCHANGER Filed April 10, 1950 4 5 Sheets-Sheet l ffQ a. a. e. Fmoav 1 Tron/Er;

y 1953 s. B. R. FEILDEN EI'AL 2,639,125

' FLUID TO FLUID HEAT EXCHANGER Filed April 10, 1950 '5 Sheets-Sheet 2 y 1953 G. B. R. FEILDEN EI'AL 2,639,125

FLUID TO FLUID HEAT EXCHANGER Filed April 10, 1950 5 Sheets-Sheet 3 wriwan! 1 rrausr:

y 1953 s. B. R. FE|LDEN ETA1 2,639,125

FLUID TO FLUID HEAT EXCHANGER Filed April 10, 1950 5 Sheets-Sheet 4 e}- 5 1 2 I o o o o 0 INDIA/[73' M y 9, 1953 G. B. R. FEILDEN arm. 2,639,125 FLUID To "FLUID HEAT EXCHANGER v 5 Sheets-Sheet 5 Filed April 10, 1950 Mil/70E;

a. 5.2. FE/LDEN Patented May 19, 1953 UNITED STATES PATENT OFF l-CE FLUID TO FLUID HEAT EXCHANGER Geofirey Bertram Robert "Feilden, Lincoln, and

Raymond Ernest Wigg, Ealing 'Common, London, England, assignors to Ruston & Honnshy Limited, Lincoln, England, a British company Application April 10, 1950, Seria'LLNo. 155,032 In Great Britain April 14, 1949 7 Claims. I

This invention relates to heat exchangers for transferring heat from .one moving body of fluid to another, without admixture and preferably recuperatively by counterflow of the fluids in their respective passages. More particularly, the invention refers to tubular heat-exchangers in which one fluid is passed through :a number of parallel tubes enclosed in a casing or casings through which the other fluid circulates in contact with the outer surfaces of the tubes.

The invention is applicable to heat-exchangers for incorporation in gas-turbine power-plants for utilising otherwise Waste exhaust-"heat to heat the compressed charge before combustion, thereby improving the thermal efficiency of the cycle. However, the improvements comprised in the present invention are not confined "to .this particular application but may find application in heat-exchangers for other purposes, nor are they confined to heat-exchangers in which both the fluids participating in the "heat-transfer are gaseous, but may find application in heatexchangers in which one or both of the fluids are liquid or in evaporators or condensers in which at least one of the fluids changes from theliquid to the vapour phase or vice versa.

In a large tubular heat-exchanger having a great number of tubes, acute problems are set by differential expansion effects and from this aspect large mono-bloc structures present great constructional difficulties. Such structures also present difiicult problems in connection with assembly and maintenance-including cleaning, repair and replacement of components-end their size usually prohibits any possibility of rigtesting for checking performance.

The solution of these problems and others as may hereinafter be discused forms the object of the present invention which makes use of a multi-bloc type of construction in which the individual tube-blocks are reduced to a manageable size, are mounted so that they can expand difierentially without imposing stresses on their mountings or on each other and can each be easily removed and i e-assembled without interference with the other tube blocks for cleaning, repair, testing or replacement. Reliable indications of the performance of the whole heatexchanger can be obtained from rig-tests carried out on a single tube-block.

A tubular heat-exchanger according to this invention is primarily characterised by a number of independent parallel blocks of tubes, in each of which the tubes are fixed at each end in a header plate, that at one end being secured to a "2 collector member over an opening therein, the joint between the *header-plateand "the collector member being fluid-tight, and that at theother endbeing provided with a funnel-shaped tubular extensionor cowl, which is supported in anopening in another=colledtor member by means of a fluid-tight expansion joint; and each block of tubes is encased for a considerable part of its length in a closely fitting casing leaving the tubes exposed at both ends, "the "fluid which circulates in contact with the outer surfaces of the tubes being compelled to pass through these tubebloc'k casings by a bulkhead subdividing the interior of the external casing of 'the exchanger into two compartments and having openings receiving'thc tubebl'ock casings, the joints between the bulkhead openings and tube-block casings being sealed any convenient manner. The arrangement is such that one fluid is passed through the tubes from thecollector having the sliding glands to the other in which the tube-blocks are located (or in the reverse direction), while the other fluid, admitted into the compartment of the outer casing on one-side of "the "bulkhead, circulates through the spaces between the tubes within "the casings of the individual tube-blocks in theopposite direction to that in which the first mentioned -fluid circulates within the tubes and emerges into the compartment of the outer casing on the opposite side of the bulkhead, whence it is exhausted.

'In a preferred embodiment of the invention the tube-blocks are disposed horizontally and the casings of each individual tube-block is provided with longitudinal horizontal flanges, preferably at the 'top, whereby the tube-block is supported on rollers, preferably located at or near each end of the tube-block casing and optionally at an intermediate point or points as well, the rollers being mounted on frames 'or bracket structures, secured to the outer casing of the exchanger or to the transverse bulkhead.

In a preferred form of construction the collector members are subdivided vertically, each branch being connected to a bank of vertically superposed tube-blocks, and the several collector branches being interconnected by an integral common header member at the top. Further, the casings .of the individual tube-blocks are flanged near one end and these flanges abut on the margins of the openings in the bulkhead and carry .stifiening brackets extending normally from the flanges and having holes through which studs projecting from the bulkhead pass to re- =ceive nuts by which the brackets and flanges are clamped to the bulkhead to secure the blockcasings thereto and provide an effective seal. These nuts are extended beyond the end of the studs to receive threaded tie-rods which pass through holes in lugs secured to the branches of the collector member at that end of the tubeblock assembly to receive clamping nuts which carry the end loads on the collector member due to the internal fluid pressure in the tube-blocks. The tensile loads imposed on the tie-rods by the clamping nuts are transmitted back through the extended nuts and studs to the bulk-head, and are ultimately counteracted by the equal and opposite end loads, due to the internal fluid pressure, acting on the collector member at the other end of the tube-blocks, these last-mentioned end loads being transmitted back to the bulkhead through connections of the latter collector member to the outer casing, the tube-blocks themselves being connected to the last-mentioned collector member by expansion joints.

The compartment of the outer casing containing the inlet for the fluid which circulates round the outside of the tubes is made of large capacity to ensure low fluid velocity therein and even distribution of the fluid to the several tubeblocks and the bulkhead may be set back some distance beyond the entry ends of the tube-block casings from the end wall of this compartment.

The fluid inlet or outlet of each collector memher is brought out through the wall of the outer casing through any convenient type of seal.

The tube-blocks are preferably of rectangular cross-section enabling them to be compactly arranged with small clearances between them; and are preferably similar, so that they are interchangeable.

Any one or more of the tube-blocks can be removed and replaced by removing the (detachable) end wall of the outer casing, the clamping nuts, tie-rods and extended nuts, and disconnecting the collector member and withdrawing it, thus enabling the tube-blocks to be slid out, and this is facilitated by the roller method of support. When a tube-block has been slid out a certain distance, a traveling slinging tackle suspended on a gantry extending longitudinally from a position next the detachable end Wall of the outer casing and located above the level of the tube-blocks can be used to support the overhung end of the block while it is being further withdrawn, the slinging tackle comprising a yoke carrying a pair of rollers correctly spaced for slipping under the flanges of the tube-block casings.

It will be seen that each tube-block can expand lengthwise independently of the others, when the exchanger is in use, and that no racking strains are imposed on the collector members or the outer casing. Further, the fluid circulating outside the tubes is confined by the tubeblock casings to paths in close contact with the tubes throughout the greater part of their length.

A further object of the invention is an improved form of flexible joint which may be used for the fluid-inlet connection of the outer casing of a heat-exchanger as described above.

In our improved flexible joint, the mating openings are provided with mutually facing metal flanges which are joined by a short flexible sleeve of asbestos-base fabric or like material clamped at its edges to the flanges by means of metal clamping strips. The asbestos may be rendered impermeable by any suitable treatment. The clamping strips may be secured by bolts passing through the flanges and the margins. of the as:

4 bestos fabric sleeve, which may be made from a strip of the fabric with a sewn, stapled or riveted seam.

If the openings are rectangular or of any other shape having corners, a protective angle piece of sheet metal may be inserted at each corner between the fabric sleeve and the ends of the clamping strips, which may be bent outwards and bolted together.

A specific embodiment of the invention is illustrated in the accompanying drawings by way of example only and without implied limitations of the scope of the invention, which is defined in the appended claims.

In the drawings,

Figure l is a perspective view, partly broken away, of a heat-exchanger;

Figure 2 is a view of the same in side elevation partly broken away;

Figure 2a is a sectioned enlargement of the part of Figure 2 ringed with a dotted line;

Figure 3 is a view in end elevation of the intake collector member of the internal fluid-circulating system of the heat-exchanger;

Figure 4 is a plan view of the discharge collector assembly of the internal fluid-circulating system with the top wall removed;

Figure 5 is a detail view in end elevation of the flexible joint connecting the inlet opening of the heat-exchanger casing with an inlet trunk;

Figure 6 is a view in section on the line 6-6 of Figure 5;

Figure 7 is a View in section on the line 1-1 of Figure 6;

Figure 8 is a view in side elevation illustrating the arrangements for extracting the tube-blocks from the heat-exchanger.

The heat-exchanger comprises a generally rectangular outer casing l0 having an internal transverse bulkhead I I, in which are rectangular openings [2. The interior of the outer casing is thereby divided into two compartments, of which the smaller, lying to the right of the bulkhead in Figure 1, has a rectangular inlet opening l3 at the top, the left-hand end of the outer casing H! (as seen in Figures 1 and 2) being open to an exhaust collector (not shown).

Within the outer casing are disposed a number of similar, rectangular-section tube-blocks I4, disposed longitudinally of the outer casing and closely spaced. Each tube-block comprises an open-ended rectangular casing l5, which passes through and fits closely into one of the openings I2 of the bulkhead and encases a bundle of closely spaced parallel tubes [6. The latter extend beyond the casing l5 and are exposed at both ends of the tube-block. The ends of the tubes l6 exposed in the compartment of the outer casing to the right of the bulkhead I l in Figure 1 are secured in a header plate 11, the opposite ends of the tubes being secured in a header plate [8, the edges of which are secured in a tubular cowl IS. The fluid-conveying connections of the tube-blocks comprise an intake collector member 20 communicating with the cowls l9 and a discharge collector assembly comprising thrce tubular collectors 2! communicating with the tubeblocks l4 through the header plates 1.

The collectors 2! are disposed vertically and each communicates with a bank of vertically superposed tube-blocks. Each collector has a number of short branches 22 of rectangular cross-section corresponding in siz and position to the tube-blocks and terminating in openings over which the header plates I1 flt. Each header plate I! has a marginal flange 23, which fits over the of the corresponding brand-1:22 ,1 the. joint beingmade fluid tighti by suitablev packing, and is:- secured to the collector 2 t by tie bolts Zfiwhich are inserted through apertured' brackets. cxtending from the collector and'carry clamps 2-6 engaging behindthe marginal flange-23;

The. discharge collectcr assembly also includes a header comprising three-elbows idsecurcda to the collectors 2 I, two outlet. pipes 23! forming continuation-s of: the" outer elbows 2:8'and branch pipes 36 connecting the: central elbow 28 withthe outlets. 29:, which are led out ofthe outer casing I-u-throughfluid-tight glands M The intake. collector member M comprises three vertical. blind-ended tubes 32 having cpen-ingsprovided. with skirts 33. which receive the open ends of the cowls l9 together with an integral header of doubleyolrexformcomprising two intake elbows 34- having branches 35, 35,. of which branches 35 con-imunicate with the outer'two collector tubes 32 and branches 36 with the central collector tube 32'. Branches 35 fidextend through a plate 3-? which is welded to the branches allroundthe margins oi the openingsthrough which'thebranches pass; and this plate forms a detachable part of. the top wall. of the i3,- being, secured in any convenient way. The lower ends of the collector tubes 32 are provided with dowels 38 which. are: received in sockets 5i onthe. base-of the outercasing Hi. The coilector' member 20 is thus positively located by the plate ill and dowels 38. The elbows 28 and 3d of the collector assembly 2|, 2? and the collector member 20 are provided. internally with flow-straightening cascades 5T.

Expansion joints are provided between the ccwls N! of the tube-blocks Ill the sl s 3-3 of the openings in-the collector-tubes 3 2' of the collector member 20'. The sklrts-33 cylindrical and the cowls [9' terminate in cyli a1 portions 58, which flt-sli'd ingly' in the shirts 33 and are provided with circumferential grooves holding split spring sealing-rings- 59.

The upper wall of each tube-block casing i5 is extended laterally to form longitudinal horizontal flanges 39; which are accommodated in slots 49 formed in the bulkhead openings l2, and by which the tube-blocks M are supported on rollers 4! mounted on bracket structures it secured to the bulkhead I l and to the inner faces of the walls of the outer casing I0.

The tube-block casings l5 also have collar-like flanges 43, which abut on the margins of the bulkhead openings l2, the joints being suitably packed to render them fluid-tight. The flanges 43 are stifiened by gusset plates 44 and carry stirrup brackets d5 extending normally to the plane of the flanges and away from the bulkhead H. Studs 46 secured to the bulkhead extend through holes in the brackets 45 and carry clamping nuts 4! by which the tube-block casings 15 are secured to the bulkhead.

The nuts 4'! are extended to receive threaded tie-rods 4B which pass through apertured lugs 59 extending from the collectors 2! and carry abutment nuts 50. Internal fluid pressure in the tube-blocks exerts forces on the collectors 2i tending to move them away from the bulkhead l l and these forces are unresisted by the tubes l6 which are free to slide in the tube-block casings H3. The lugs 49, abutment nuts 50, ties 4B, nuts 4i and studs 46 transmit these loads back to the bulkhead ll, while the corresponding forces on the collector tubes 32 of the collector member 20 at the opposite end of the heat-exchanger are 6 transmitted directly to the outer casing Why the 1313213931- and' dowels 38-.

The end of the outer casing I0 enclosing the collector-assembly 2|; 21 is constituted by a detachable cover 52, the. joint indicated at 53 between which and the main body of the outer casing being formed by tongue andgroove elements and the cover 52 being secured by tie-bolts- 54 whoseheads engage apertured lugs 55 extending inwardly from the wall of the main body of outer casing to and which carry external securing nuts 56.

Removal of the cover 52 gives access. to the collectors 2 lwhich are provided. with detachable manhole covers lit-giving access to their insides- By undoing the for cleaning and like purposes. joints between the collectors 21- and the header 21, removing the abutment nuts 50 and slacking off the tie-bolts 24 to release the clamps 26 from, the-marginal flanges 23 of the header plates H the collectors can be removed bodily. This gives access to the tube-blocks it which can be extracted singly by lengthwise sliding after u-nscrewing the clamping nuts 41 from the studs 46.

This operation is facilitated by the. provision, of an external gantry (see Figure 8) consisting of a bridge structure 6| supporting an I-joist 62, which extends longitudinally from the outer casing at a level above the tube-blocks and carries travelling slinging gear comprising a traveller 63 manually movable by means of a chain 64 and having. a slinging hook 65,. onv which isslung a yoke 66 carrying a pair of rollers 61,. spaced apart at the correct distance to be engaged under the flanges 3.9 of the tube-block M and take the weight of the latter as it isremoved by end-wise sliding fro-mthe support- 0f the rollers 4| mounted in the outer casing: 16.

The inlet opening it of theouter casing l0 communicates with a pair of inlet trunks 69 i of a flexible joint (see Figures 5 to 7). The margin of the plate 58 is of angle section and presents a flange Ill facing the margin of opening it, while fixed to the outer casing I0 and surrounding the opening 13 is an angle section coam-ing H, whose flange 12 faces and mates with the flange 10. A flexible sleeve 13 of graphited asbestos fabric (the seam of which (not shown) may be sewn or stapled) is slipped over the mating flanges 1c, 72 and secured thereto by metal clamping strips 14 secured by bolts 15. At the corners the strips 14 are bent outwards and the adjacent bent ends are secured together by bolts l'fi, a metal angle piece 11 being inserted at each corner to hold the fabric sleeve against the flange H! or 12.

The heat-exchanger described above is de signed for incorporation in a stationary gas turbine for utilising exhaust heat to preheat the air leaving the compressor before entering the combustion chambers; Hot turbine-exhaust gas enters one compartment of the outer casing through opening l3, circulates through the tubeblock casings l5 and is exhausted from the other compartment of the outer casing, and it will be seen that it cannot pass from one compartment to the other without passing through the tubeblock casings in close contact with the tubes l6, through which air from the compressor, entering by way of the collector member 20, circulates in the opposite direction and is discharged through A the collector assembly 2|, 2! to the combustion chambers, the heat-transfer being recuperative.

We claim:

1. A multi-block tubular heat-exchanger comprising an outer casing, a transverse bulkhead having openings therein and dividing the interior of the casing into two compartments, one compartment having an inlet opening and the other compartment having an outlet opening, a collector member in each compartment extending outside the casing for admission of fluid to one collector member and discharge of fluid from the other collector member, said collector members having openings therein, a number of closely spaced parallel tube-blocks, each comprising an open-ended tubular casing inserted through one of the openings of the bulkhead and secured to the bulkhead in a substantially fluid-tight manner, a bundle of closely spaced parallel tubes housed in said open-ended casing and extending beyond both open ends thereof, and a header plate secured to the tube ends at each end of the tube-block, one of said header plates being secured in a fluid-tight manner to the collector member in one compartment of the casing so as to register with an opening thereof, a tubular cowl-like extension of the other header plate registering with an opening of the other collector member, and a fluid-tight expansion joint between the cowl-like extension and the lastnamed collectors member permitting movement of the cowl-like extension relatively to the collector member in the axial direction of the tubeblock.

2. A tubular heat-exchanger as claimed in claim 1, in which each tube-block casing has horizontal, longitudinal flanges, and the outer casing includes internal bracket structures and rollers mounted thereon, said rollers supporting the tube-blocks by engagement with the undersides of the horizontal flanges thereof.

3. A tubular heat-exchanger as claimed in claim 1, in which the tube-block casings have external flanges abutting on the margins of the openings of the bulkhead and apertured bracket 8 structures extending normally from the flanges, and the bulkhead has studs extending therefrom through the apertures of the bracket structures, together with clamping nuts screwed on to the studs and engaging the bracket-structures for clamping the flanges to the bulkhead.

4. A tubular heat-exchanger as claimed in claim 3 including threaded tie-rods screwed into the clamping nuts, which are extended for this purpose, apertured lugs extending from the collector member on the same side of the bulkhead as the tie-rods, which extend through the apertures of the lugs, and abutment nuts screwed onto the tie-rods and engaging the lugs to resist the tendency of the internal pressure in the tube-blocks to move the collector member away from the bulkhead.

5. A form of construction of heat-exchanger as claimed in claim 1, in which there are at least two banks of vertically superposed tube-blocks and each collector member comprises at least two vertical branches and a common header element interconnecting the branches at the top.

6. A form of construction of heat-exchanger as claimed in claim 1 in which the tube-blocks are of rectangular cross-section.

7. A form of construction of heat-exchanger as claimed in claim 1, in which the several tubelocks are similar and interchangeable. GEOFFREY BERTRAM ROBERT FEILDEN. RAYMOND ERNEST WIGG.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,639,225 Grace Aug. 16, 1927 1,696,435 Fraley Dec. 25, 1928 1,883,605 Davy Oct. 18, 1932 2,125,972 Wilson et al Aug. 9, 1938 2,269,619 Carpenter Jan. 13, 1942 2,285,651 Fischer June 9, 1942 FOREIGN PATENTS Number Country Date 228,297 Switzerland Nov. 1, 1943

Images