US3195626A - Heat exchanger - Google Patents

Description

July 20, 1965 F. DRUsElKxs ETAL 3,195,626

HEAT EXCHANGER 3 Sheets-Sheet 1 Filed July 9, 1962 M 0 om; WEEE S/ E www w@ .6 MT RRR ff DBI. 60M mi.

ATTU/PA/Ey July 20, 1955 F. DRusElKls ETAL. 3,195,626

HEAT EXCHANGER (E n INVENTORJ N FREDE/P/CK DRl/sE/K/s E IMBERT W AL TTOFNEV July 20, 1965 F. nRusElKls ETAL, 3,195,626

HEAT EXCHANGER 3 Sheets-Sheet Z5 Filed July 9, 1962 INVENTORS FEEDER/cfr RusE//f/s R spr m HALEY PA aL fa A60/vaak@ A TTORNEV United States Patent O eration of Delaware p Filed .luly 9, 1962, Ser. No. 203,316

7 Claims. (Cl. 16S-179) This invention pertains to heat exchangers, and particularly to a heat exchanger having internal and external extended surfaces.

Heretofore, sheet metal heat exchangers having internal and external extended surface portions, in the form of tins, have been made from strip stock having laterally otlset edges, which strip stock is spirally wound with adiacent convolutions overlapping and rigidly united. to form a tube. This type of heat exchanger tube has spiral internal and external tins which lfacilitate the exchange of heat between fluids inside and outside thereof. The pres-V ent invention relates to a heat exchanger comprising a plurality of rings arranged in stacked relation, each ring having an external annular iin and a plurality of spiral, or helical internal iin segments. When the rings are assembled in stacked relation and rigidly secured together, they form a tube having spaced, external annular ns and internal spiral fins which deiine a plurality of helical passages therethrough.

Accordingly, among our objects are the provision of an improved extended surface tubular heat exchanger; the further provision of a tubular heat exchanger having equidistantly spaced, parallel, external annular tins and segmental helical internal fins which define a plurality of helical internal passages therebetween with a central opening therethrough; the further provision of a heat exchanger of the aforesaid type having core means for the central opening defined by the inner edges of the segmental internal helical fins; and the still further provision of an improved heat exchanger section, or ring, having an annular external tin, an annular body with multiple otlset portions, and a plurality or" internal helical n segments.

The aforementioned and other objects are accomplished in the present invention by nesting, or intertting, the annular body portions of a plurality of heat exchanger sections to orm a tubular stack with the radial ends of the internal helical segmental fin portions or" adjacent sections abutting, and thereafter rigidly securing the plurality of sections together by copper brazing or Welding. Specilically, as disclosed, the annular body of each heat exchanger section is formed with multiple oitset portions between its ends to provide spaced, intermediate annular stop shoulders. One edge of each section is outwardly flanged at right angles to the annular body to form an annular external lin, and the other edge is formed with four inwardly extending helical iin segments, the inner peripheral edges of which denne a circular central hole. The internal helical lin segments of the stacked heat exchanger sections define four spiral passages therethrough. The tubular heat exchanger can be used with or without a central core which, if used, completely closes the central hole through the stacked sections.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein preferred embodiments of the present invention are clearly shown, and wherein similar numerals depict similar parts throughout the several views.

and partly in elevation, ot a forced warm air furnace ldh Patented .lilly 2t), i955 embodying the heat exchanger of the present invention, taken generally along line l-ll of FIGURE 2.

FIGURE 2 is a fragmentary view, partly in section and partly in elevation, with certain parts broken away, taken along line 2-2 of FIGURE 1. s

FIGURE 3 is an enlarged fragmentary sectional view taken along line 3 3 of FIGURE 1.

FIGURE 4 is an enlarged perspective view of one end of thc improved heat exchanger section.

FIGURE 5 is an enlarged perspective view o' the other end of the improved heat exchanger section.

FIGURE 6 is a fragmentary View, partly in section and partly in elevation, or" a modified form of the heat exchanger.

With reference to FGURES l and 2, the improved heat exchanger is shown in combination with a forced warm air furnace having a casing Il@ comprising front, rear and side walls, with a top wall l?. suitably secured thereto and a bottom wall, not shown. In addition, the casing lil has an intermediate substantially horizontal partition wall i4: dividing the casing into an upper compartment lo and a lower compartment t8. A conventional motor driven blower 2t? is located in the lower compartment ld, the blower, when operating, discharging air to be heated into the upper compartment le for delivery through an opening 22 in the top Wall l2. The upper chamber ld has a vertical partition 2d attached to the top wall 12 and the horizontal partition lid, the partition 2d constituting a mounting plate for a lue gas collector box 26 and an integral combustion shell and heat exchanger assembly 2S, the collector box 2d and the assembly 2S being disposed on opposite sides of the partition panel 24. The interior or the tlue gas collector box communicates with a stack 3d through an opening in the top wall l2 of the casing.

The integral heat exchanger and combustion shell assembly 23 is shrouded by a pair of side battles 31 which coniine air flow from the blower to a path contiguous to the extended surface portions of the heat exchanger. The assembly 2S comprises a header 32 which is supported by a bracket 354, and has a plurality of substantially vertically extending, laterally spaced U-shaped tins 36 welded, or brazed, to its end wall. The integral cornbustion shell and heat exchanger assembly 23 also comprises a multiple section, externally inned combustion shell 3d, and a pair of multiple section, externally iinned heat exchanger tubes (lil. A fuel burner ft2 is supported by the partition panel 2d and extends into the tubular combustion shell 3b.

Referring to FIGURE 3, the combustion shell 38 comprises a plurality of nested, or interlitting, rings dil. Each ring di has an annular body with an outwardly extending annular iiange 4d along one edge and an inwardly extending annular lange ed at its other edge, with an otlset in its annular body intermediate its edges to forni an annular stop shoulder Thestop shoulders Sti on the rings 44 enable the plurality of rings dil to be assembled in stacked, nested relation to form a double thickness wall, which nested, or intertted, rings are rigidly secured together such as by welding, or brazing. The inwardly extending annular llanges define a central circular opening 52 for accommodating the burner ft2. A cornbustion shell mounting ring 54 has a neck portion 56 suitably secured to the periphery of an opening in the partition panel 24, and supports a transfer ring 53. Both the mounting ring 54 and the transfer ring 5S have outwardly extending annular ianges do, the llanges lo on the several sections constituting integral extended surface portions, or tins.

The header 32, as seen in FIGURE 3, comprises a junction plate at) and a dishshaped cover 62, the cover 62 having a flanged edge d4 over which the edge 66 of the aisance tion 63 adapted to interfit with the end ring 44 of the combustion shell.

Thus, the ring portion 68 is offset intermediate its edges to form an annular stop shoulder 7 y for the end ring 44, and likewise has an inwardly extending annular flange portion 72 at its outer edge. It is to be understood that the end ring 44 is welded or otherwise suitably connected to the ring portion 68.

. Referring to FIGURES 4 and 5, each heat exchanger tube 4% comprises a plurality of nested, or interfitted, ring, or cup, sections 74. The rings 74 are preferably formed of sheet metal which is stamped and drawn to the desired form. Each ring 74 has an annular body 76 with a pair of odsets between its ends to provide axially spaced annular shoulders 78 and 80 of different diameter. In

' the assembly of the rings only one of the shoulders 78 or @il is used as a stop. One end of each ring 74 is formed with an outwardly extending annular flange 82, and the other end of each ring is formed with four inwardly extending segmental helical fins S4. Each segmental helical n S4 has axially offset, substantially radial ends S6 and 8S, with the ends adjacent the fins being in substantial alignment with each other although axially spacedN apart. The inner peripheral edges Siti of the segmental fin 84 are arcuatey such that when a plurality of rings '74 are interfittedwith each other, ,the radial ends of the helical fin segments of adjacent rings abut each other, and the inner peripheral arcuate edges 90 define a substantially circular hole 92 throughfthe tubular heat'exchanger 4t) as seen in FIGURES l and 3.

Each heat exchanger tube 40 comprises a stack of interfitted rings 74, each shoulder Sti forming a seat, or stop, for each adjacent ring so as to equidistantly space the annular external flanges, or fins, 82 which lie in spaced parallel planes. The offset portions of the annular bodies 76 of adjacent rings form a continuous double thick-V ness side wall for each heat exchanger tube 40, adjacent rings being rigidly secured together such as bywelding, or brazing, the offset annular body portions thereof. In addition, during assembly of the rings 74 to form the heat exchanger tube 40, the axially outward offset radial ends 83 of the four segmental helical fins l84 of each ring 74 are arranged to abut the axially inward offset radial ends 86 of the segmental helical fins of the'next succeeding ring 74 from theheader 32 to the partition panel 24. By so interfitting the rings 74 four separate and distinct spiral, or helical, passages 94, 95, 96 and 97 are formed by the segmental internal helical fins of the several rings 74 throughout the length of each heat exchanger tube 4t). Each helical passage 94, 95, 96 and 97 makes a complete turn through the axial distance of four rings 74. Moreover, as alluded to hereinbefore, the interfitted rings 74 define a substantially circular central through passage 92.

.The junction plate 60 is formed with a pair of integral ring portions 9g adapted to interfit with the end ring 74 of each tubular heat exchangerV 40.V Each ring portion Sie has two intermediate offsets forming an annular stop shoulder lili), the end ring 74 being welded or otherwise suitably connected to the ring portion'98.

At the other end of each heat exchanger tube, the shoulder 3i) o end ring 74 seats against a complementary oset portion of a mounting ring 1tl6 having a shoulder we. The mounting ring 106 has its inner edge 110 clinched over the peripheral edge 114 defining an opening in the partition panel 24.V A transfer ring 116 seats against the shoulder 103 of the mounting ring 106, both the transfer ring 116 and the mounting ring 106 having outwardly extending annular tins 82.

In a modified embodiment as Ashown in FIGURE 6, the heat exchanger tube 4@ has a central tapered core 126 with an imperforate end cap 122, the core 126 extending through the circular opening 92 formed through the nested vring sections 74 so aslto 'substantially close the same.

In this embodiment the flow of fluid internallyV of the heat exchanger tube 40 is substantially confined to the four helical passages 94, 95, 96 and 97 formed by the internal'segmental helical fins of the ring sections 74. While the Vcore 12@ increases the restriction to flow through the heat exchanger tube, it also increases the efficiency of heat transfer between the internal and external fluids, be they gaseous or liquids, since substantially all of the internal fluid must flow in multiple spiral paths and is thus in intimate contact with the internal cxtended surface portion-s of the heat exchanger tube throughout its length. The core can be of different lengths, as shown in phantom in FIGURE 6, to obtain the desired heat transfer eiciency.

In both embodiments of the improved tubular heat exchangers disclosed herein, thegnumber of internal helical passages formed'by the segmental helical fins can be changed by varying the number of regimental helical Vfins on each ring section. The extent of the axial flow required for a complete turn, or revolution of the fluid through the helicalpassages is directly proportional to'the number of segmental helical fins on each section. Thus, with the specifically disclosed ring sections, the fluid traverses an axial distance of four'ring sections while making a complete turn.' The multiple helical passages greatly increase the efiiciency of heat transfer between the internal and external tiuids.

While the embodiments of the invention as herein disclosed constitute preferred forms, it is to be understood that other forms might be adopted.

We claim: l

1. A tubular heat exchanger including,- a plurality of interiitting rings, each Vring comprising an annular body having an outwardly extending, annular fin at one end and a' plurality of inwardly extending, segmental helical fins at Vits other end, stop means on said annular body engageable with the adjacent ring Vto space the annular fins equidistantly apart, the ends of the segmental helical fins of adjacent rings abutting each other and defining a plurality of internal helical passages in the heat exchanger equal to the number of `segmental helical tins on each ring.

2. A tubular heat exchanger including, a plurality of interfitting" rings, each ring comprising an annular body having an external, annular fin at one end and a plurality of internaL'segmental helical fins at its other end, means on said annular body defining a stop for the adjacent ring to space the external fins equidistantly apart, the internal segmentalv helical fins of each ring having arcuate inner peripheral edges with the internal segmental helical tins of adjacent rings abutting each other to define a plurality of internal helical passages in said heat exchanger equal to the number of internal segmental helical fins on each ring, the arcuate inner peripheral edges of the internal segmental fins on adjacent rings defining a substantially cylindrical passage through the heat exchanger.

3. The tubular heat exchanger set forth in claim 2 including a tubular core having a closed outer end disposed Within said substantially cylindrical through passage so as to substantially close the central through passage.

4. A tubular heat exchanger including, a plurality of interfitting rings, each ring comprising an annular body having an external, annular'fin at one end and a plurality of internal, segmental helical fins at its other end, means on said annular body constituting a stop for the adjacent ring tospace the external fins equidistantly apart, adja- Y cent internal segmental helical fins of each ring having axially offset, radially aligned ends, the axially outward offset ends of the segmental helical fins on each ring abutting the axially inward offset ends of the segmental helical fins on the next adjacent ring to define a plurality of internal `helical passages Vin the heat exchanger equal to the number of segmental helical fins on each ring.

5. A tubular he'at exchanger including, a plurality of interfitting rings, each ring comprising Van annular body having an external, annular fin at one endand a plurality of internal, segmental helical fins .at its other end,

area-5.26

means on said annular body constituting a stop for the adjacent ring to space the external fins equidistantly apart, adjacent internal segmental helical tins on each ring having axially offset aligned, substantially radial ends, the radial ends of the segmental helical ns of adjacent rings abutting each other and defining a plurality of internal helical passages in the heat exchanger equal to the number of segmental helical ns on each ring with each helical passage making a complete turn throughout the axial distance of the number of intertting rings equal to the number of internal segmental helical tins on each ring.

6. The tubular heat exchanger set forth in claim 5 wherein the means on the annular body constituting a stop for the adjacent ring comprises an olset in said an- 15 nular body intermediate its ends delining an annular stop shoulder.

7. The tubular heat exchanger set forth in claim 5 wherein the inner peripheral edge of each segmental helical tin on each ring is arcuate, and wherein adjacent arcuate inner peripheral edges of the internal segmental helical tins of said plurality of interfitting rings define a substantially cylindrical passage therethrough.

References Cited by the Examiner UNITED STATES PATENTS 1,886,533 l0/32 Thomas 165-179 2,703,701 3/55 Simpelaar 165-141 2,925,830 2/ 60 Kantrowitz 165-179 3,068,905 12/ 62 Millington et al 165-179 X FOREIGN PATENTS 514,015 ll/20 France.

CHARLES SUKALO, Primary Examiner.

Claims (1)

1. A TUBULAR HEAT EXCHANGER INCLUDING, A PLURALITY OF INTERFITTING RINGS, EACH RING COMPRISING AN ANNULAR BODY HAVING AN OUTWARDLY EXTENDING, ANNULAR FIN AT ONE END AND A PLURALITY OF INWARDLY EXTENDING, SEGMENTAL HELICAL FINS AT ITS OTHER END, STOP MEANS ON SAID ANNULAR BODY ENGAGEABLE WITH THE ADJACENT RING TO SPACE THE ANNULAR FINS EQUIDISTANTLY APART, THE ENDS OF THE SEGMENTAL HELICAL FINS OF ADJACENT RINGS ABUTTING EACH OTHER AND DEFINING A PLURALITY OF INTERNAL HELICAL PASSAGES IN THE HEAT EXCHANGER EQUAL TO THE NUMBER OF SEGMENTAL HELICAL FINS ON EACH RING.

Images