US1657463A - Radiator core - Google Patents

Radiator core Download PDF

Info

Publication number
US1657463A
US1657463A US120608A US12060826A US1657463A US 1657463 A US1657463 A US 1657463A US 120608 A US120608 A US 120608A US 12060826 A US12060826 A US 12060826A US 1657463 A US1657463 A US 1657463A
Authority
US
United States
Prior art keywords
strip
air
strips
tubes
air tubes
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US120608A
Inventor
John M Fedders
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fedders Manufacturing Co Inc
Original Assignee
Fedders Manufacturing Co Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fedders Manufacturing Co Inc filed Critical Fedders Manufacturing Co Inc
Priority to US120608A priority Critical patent/US1657463A/en
Application granted granted Critical
Publication of US1657463A publication Critical patent/US1657463A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28HEAT EXCHANGE IN GENERAL
    • F28DHEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D1/00Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators
    • F28D1/02Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid
    • F28D1/03Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with plate-like or laminated conduits
    • F28D1/0358Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with plate-like or laminated conduits the conduits being formed by bent plates
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28HEAT EXCHANGE IN GENERAL
    • F28DHEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D1/00Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators
    • F28D1/02Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid
    • F28D1/03Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with plate-like or laminated conduits
    • F28D1/0308Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with plate-like or laminated conduits the conduits being formed by paired plates touching each other
    • F28D1/0316Assemblies of conduits in parallel
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S165/00Heat exchange
    • Y10S165/355Heat exchange having separate flow passage for two distinct fluids
    • Y10S165/356Plural plates forming a stack providing flow passages therein
    • Y10S165/373Adjacent heat exchange plates having joined bent edge flanges for forming flow channels therebetween
    • Y10S165/374Liquid to air heat exchanger having liquid passage formed by joined sheets
    • Y10S165/376Air passages defined by spacing projections of sheets
    • Y10S165/377Spacing projections formed by folded sheet portions

Definitions

  • Figure 3 is a top plan view of a portion of the radiator core containing; my improvements, as shown in Figs. 1 and 2.
  • Figure l is a horizontal section. taken on line lfl Fig. 2.
  • Figures 5 and 6 are perspective views of one section of a radiator unit made in cordance with the construction shown in Figs. 1 to d. i
  • Figure 7 is a tragnientary front elevation at a radiator core containing my invention but slightly modified as con'ipared with the construction shown in Figs. 1 to 6.
  • this radiator core as shown in Figs. 1 to 6 comprises a plurality of water pas s instant case are arranged vertically,and a plurality of air tubes ll, 12 which are arranged between said water passages.
  • Each of the water passages 10 is formed hat-ween the opposi sides of two sheet metal strips so thatthis passage is arranged vertically.
  • Each of these sheet metal strips nreiterably made of very thin copper. or similar metal site and provided at its oppoical edges with laterally oil-set hanges 13; ot a companion 10 which in the a head, the opposite ends which are adapted to engage with.
  • the oft-set flanges 18, 13 at opposite longitudinal edges ot' the two cooperating strips of metal are securely connected with each other by soldering; or otherwise to form. a lealt-ti 'ht joint between the same for preventing the escape of water from the core.
  • each of the sheet metal strips is provided with laterally projecting; loops which are so constructed that the metal of the same is integrally connected with the walls of the water passages, and form a plurality of air tubes between adjacent water p ages, whereby the heat which is conducted :lrom the walls of the water passages to these air tubes is absorbed by the air passing through the same, and thereby operates to reduce the temperature of the water which passing through the water passages.
  • these air tubes may be of various terms in cross section the same are preterably ot' hexagonal iormas shown in Figs. 1 and 2.
  • each of these laterally projecting loopsof a metal strip is bent to term one complete air tube 11 ot' hexagonal form which has two of its opposing; flat sides arrangedv horizontally at the top and bottom of each tube thereof. (in that longitudinal side of each air tube 11. next to the companion wall 14 and flanges 13 ot the respective air tube, the loop torming a complete airtube 11 is connected by means of two webs 1515, with the wall 1% and flanges 13 0t the-respective metal strip so as to be connected integrally therewith, as shown in Figs. 1 and 2. On the opposite longitudinal side of each complete air tube 11.
  • the air tubes of one strip are intercalated with the air tubes of an opposing strip of an adjacent water tube and the air tubes of these two strips engage each other at their upper and lower flat sides or facets; and the longitudinal head of each of these strips engages with the wall and off-set flanges of the other strip.
  • the complete air tubes 11 are arranged in a vertical row and these in connection with the opposing walls of two adjacent strips, form two vertical rows of half tubes 12, adjacent to the outer sides of the water tube walls.
  • the half air tubes on opposite sides of each water tube present the appearance of complete air tubes, so that a radiator core when viewed from the front, as shown in Fig. 1, presents a honey-comb appearance in which each of the cells is of hexagonal form.
  • each of the air tubes only engages the opposite ends of its upper and lower sides with the corresponding parts of adjacent air tubes, as shown at 18, but the intermediate parts 19 of the upper and lower sides of the air tubes are recessed or offset inwardly relative to the end portions thereof, as shown in Figs. 2, 3, t and 5, whereby horizontal transverse air conduits are formed between adjacent air tubes of both strips, which provide a free circulation of the air cross-wise through the radiator core, and thus aid in equalizing the cooling; effect and obtaining the maximum efiioiency of the core,
  • the loops which project laterally from each sheet metal strip at intervals in. its length may be so constructed that they produce more than one vertical row of air tubes in cooperation with similar loops formed on the opposing strip of an adjacent water passage wall.
  • the loops on the opposing metal strips of their adjacent water tubes are so constructed that they produce three vertical tiers or columns of complete air tubes 20, 21,
  • each of these tubes being of hexagoiuil form in moss-section.
  • each of the sheet metal strips has its water passage wall 22 and the oli-sct flanges "i l at opposite ends thereof made of zig-zug form,
  • each of the heads is composed ol two plies ill the outer edges of which are connected with each other while the inner edges are connected respectively with the sections of the sheet metal strip on opposite sides of its summit.
  • each of these built-up air tubes being, made up by two facets of our of the strips, the adjacent web and head associated with the respective facets of the strip, one of the inner facets of the complete air tube fill on the respective strip, and one of the outer facets of the complete tube formed on an opposing strip of an adjacent water passage.
  • a plurality of such strips are as integratd, as shown in Fig. 7. the some are united with each other at their front and rear edges by means of solder as to close the joints between the pairs of strips forming water tubes, also the webs which connect the complete air tubes with the walls and flanges of the strips and also the connection between the several air tubes with each other and with the heads on the walls and flanges, so as to form a rigid structure, the several parts of which will not: become displaced under severe usage.
  • a radiator core having a plurality of water passages and a plurality of air tubes arranged between said water passages, each of said water passages having opposing walls formed by two strips of sheet metal which have their opposite longitudinal edges engaging one another and their walls intermediate of said edges spaced from each other, and each of said strips being provided at intervals with laterally projecting loops forming air tubes, and the air tubes of one of said strips being arranged in the space between similar air tubes of an adjacent strip.
  • a radiator core comprising a plurality of water passages and a plurality of air passages arranged between the water passages, each of said water passages being formed between two sheet metal strips provided with ofii-set flanges at their longitudinal edges which engage each other while their said edges are spaced apart, and each of said strips being provided at intervals with laterally projecting loops forming air tubes, each tube being integrally connected by webs on one of its longitudinal sides with one strip and provided on its opposite longitudinal side with a head, the ends of each head being provided with lugs, and the intermediate part thereof being provided with a recess, said lugs and recess engaging with the offset flanges and the wall of an adjacent strip.
  • a radiator core comprising a plurality of water passages and a plurality of air passages arranged between the water passages, each of said water passages being formed between two sheet metal strips provided with oil-set flanges at their longitudinal edges which engage each other while their walls intermediate of said edges are spaced apart, and each of said strips being provided at intervals with laterally projecting loops forming air tubes, the tubes of each strip being complete and arranged between similar tubes of an adjacent strip and forming therewith partial air tubes which alternate with the complete tubes.
  • a radiator core comprising a plurality of water passages and a plurality of air passages arranged between the water passages, each of said water passages being formed between two sheet metal strips provided with offset flanges at their longitudinal edges which engage each other while their walls intermediate of said edges are spaced apart, and each of said strips being i vided at intervals with laterally projecting loops forming air tubes, and the air tubes of one strip being arranged between the air tubes of an adjacent strip, and the air tubes of one strip having its end portion engaging with the corresponding end portube of an adjacent strip,

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)

Description

Jan. 31, 1928.
J. M. FEDDERS RADIATOR CORE Filed July 6. 1926 2 Sheets-Sheet 1 UGW'FOI" 791 A 914414004 y QM, 174
Jan. 31, 1928.
1,657,463 J. M. FEDDERS I RADIATOR CORE Filed July 6. 1926 2 Sheets-Sneet 2 Ill) Pat
JOHN M. FEDDERES, OF BUFFALO,
IEilV YORK, ASFJ'IGNOE I EDDEFLS 4G CUM'EAIWL IITQ, UTE BUF 110, NEW] "55013 11, .61 GOBPORATIQN OE MANUFACTUR- NEW YORK.
RADIATQB CORE.
Application filed Juy 6,
in connection with vide a core for such radiators which will yield a greater radiating efficiency for a given amount of metal, which be manufactured expeditiously and economically and which is strong and d bio and not l kely to get out of order when subjected to the vibrations of the car on which the same is mounted.
in the accompanying drawingsz- Figure 1. is a fragmentary front elevation of a radiator core embodying one form of my invention.
Figure eorrespondiagly a vertical section talten on the numbered line in Figure 4.
Figure 3 is a top plan view of a portion of the radiator core containing; my improvements, as shown in Figs. 1 and 2.
Figure l is a horizontal section. taken on line lfl Fig. 2.
Figures 5 and 6 are perspective views of one section of a radiator unit made in cordance with the construction shown in Figs. 1 to d. i
Figure 7 is a tragnientary front elevation at a radiator core containing my invention but slightly modified as con'ipared with the construction shown in Figs. 1 to 6.
tiimilar characters of reference indicate lilce parts in the several figures ot the drawinns;
In its general organization, this radiator core as shown in Figs. 1 to 6 comprises a plurality of water pas s instant case are arranged vertically,and a plurality of air tubes ll, 12 which are arranged between said water passages.
Each of the water passages 10 is formed hat-ween the opposi sides of two sheet metal strips so thatthis passage is arranged vertically. Each of these sheet metal strips nreiterably made of very thin copper. or similar metal site and provided at its oppoical edges with laterally oil-set hanges 13; ot a companion 10 which in the a head, the opposite ends which are adapted to engage with.
1926. serial No. 120,608.
strip, while the intermediate part or body of his strip recedes and terms an upright wall it which is spaced apart from the coinpanion wall 14: of an adjacent metal strip and forms with the same an upright water passage conduit, or pipe, which is flattened and extends with its length tore-andatt ot the rad ator core.
The oft-set flanges 18, 13 at opposite longitudinal edges ot' the two cooperating strips of metal are securely connected with each other by soldering; or otherwise to form. a lealt-ti 'ht joint between the same for preventing the escape of water from the core.
At intervals, each of the sheet metal strips is provided with laterally projecting; loops which are so constructed that the metal of the same is integrally connected with the walls of the water passages, and form a plurality of air tubes between adjacent water p ages, whereby the heat which is conducted :lrom the walls of the water passages to these air tubes is absorbed by the air passing through the same, and thereby operates to reduce the temperature of the water which passing through the water passages. lthough these air tubes may be of various terms in cross section the same are preterably ot' hexagonal iormas shown in Figs. 1 and 2.
Each of these laterally projecting loopsof a metal strip is bent to term one complete air tube 11 ot' hexagonal form which has two of its opposing; flat sides arrangedv horizontally at the top and bottom of each tube thereof. (in that longitudinal side of each air tube 11. next to the companion wall 14 and flanges 13 ot the respective air tube, the loop torming a complete airtube 11 is connected by means of two webs 1515, with the wall 1% and flanges 13 0t the-respective metal strip so as to be connected integrally therewith, as shown in Figs. 1 and 2. On the opposite longitudinal side of each complete air tube 11. the same is provided with V of which are .pro- 'vided with laterally projecting lugs 16 which engage with the oil -set flanges 13 on the opposing wall of an adjacent water tube; while the intermediate edge portion of this head is provided with a longitudinal recess 17 which receivesthe laterall bulging receding wall 14; et this last Mi l In the assembled position of a plurality of units of this character, the air tubes of one strip are intercalated with the air tubes of an opposing strip of an adjacent water tube and the air tubes of these two strips engage each other at their upper and lower flat sides or facets; and the longitudinal head of each of these strips engages with the wall and off-set flanges of the other strip.
The oint between the webs l.515 of each loop is closed by solder so as to form a leaktight joint there-between, and the beads of the air titbes on one strip are connected with the wall of an opposing strip, and the several air tubes of two adjacent units are con-- nected with each other by solder, thereby securely connecting the several parts of the radiator core and not only preventing the same from leaking, but also forming a very rigid structure which is not likely to give way and cause leakage wider severe strains.
lVhen two units are thus assembled, the complete air tubes 11 are arranged in a vertical row and these in connection with the opposing walls of two adjacent strips, form two vertical rows of half tubes 12, adjacent to the outer sides of the water tube walls. lVhen, however, a plurality of such units are assembled, the half air tubes on opposite sides of each water tube present the appearance of complete air tubes, so that a radiator core when viewed from the front, as shown in Fig. 1, presents a honey-comb appearance in which each of the cells is of hexagonal form.
In order to preserve the hexagonal appearance of the several cells of the radiator core and still permit cross circulation of air between the several airtubes for promoting the cooling effect" of the same, each of the air tubes only engages the opposite ends of its upper and lower sides with the corresponding parts of adjacent air tubes, as shown at 18, but the intermediate parts 19 of the upper and lower sides of the air tubes are recessed or offset inwardly relative to the end portions thereof, as shown in Figs. 2, 3, t and 5, whereby horizontal transverse air conduits are formed between adjacent air tubes of both strips, which provide a free circulation of the air cross-wise through the radiator core, and thus aid in equalizing the cooling; effect and obtaining the maximum efiioiency of the core,
If desired, the loops which project laterally from each sheet metal strip at intervals in. its length, may be so constructed that they produce more than one vertical row of air tubes in cooperation with similar loops formed on the opposing strip of an adjacent water passage wall. For example, as shown in Fig. 7, the loops on the opposing metal strips of their adjacent water tubes are so constructed that they produce three vertical tiers or columns of complete air tubes 20, 21,
21, each of these tubes being of hexagoiuil form in moss-section. In this constrlgurtion, each of the sheet metal strips has its water passage wall 22 and the oli-sct flanges "i l at opposite ends thereof made of zig-zug form,
sothat the facets of this strip form some oil. the facets of the air tubes.
In the preferred constriurtirm, alternate summits of each o l those sheet metal strips are provided with loops and heads which project laterally there'l'rtuu. l luch loop has its extremity shaped to form a couuilcte air tube 20, one longitudinal side of which is connected by integral wel lwith the adjacent summit of the. wall 1.3 and flanges fi l of the respective strip, so that this loop in clfect is a continuation of the strip: and each of the heads is composed ol two plies ill the outer edges of which are connected with each other while the inner edges are connected respectively with the sections of the sheet metal strip on opposite sides of its summit.
In the assembled position of two :uljuccut strips having such alternate loops and heads, the upper and lower facets of the complete tubes E20 engage with each other. and the longitudinal side of each coni 'llele tube it) engages with the outer edge of the head on the opposingstrip, so as to form two tiers of coi'nplcte built-up air tubes ill. on opposite sides of the center row ol iutcural air tubes 90, each of these built-up air tubes being, made up by two facets of our of the strips, the adjacent web and head associated with the respective facets of the strip, one of the inner facets of the complete air tube fill on the respective strip, and one of the outer facets of the complete tube formed on an opposing strip of an adjacent water passage.
hen a plurality of such strips are as sembled, as shown in Fig. 7. the some are united with each other at their front and rear edges by means of solder as to close the joints between the pairs of strips forming water tubes, also the webs which connect the complete air tubes with the walls and flanges of the strips and also the connection between the several air tubes with each other and with the heads on the walls and flanges, so as to form a rigid structure, the several parts of which will not: become displaced under severe usage.
Both forum of my invention herein dcscribed and shown in the drawings. provide the maximum radiating surface for the amount of metal which used in the con struction of the core. The some also per mits of a very effective flow of air through the radiator core for carryinu away the heat of the water by convection, and the same is also of such a construction that the strips can be readily formed economically and expeditiously by machinery and assembled Elli lllli walls intermediate of with each other for producing complete ra diator cores without involving undue cost.
I claim as my invention:
1. A radiator core having a plurality of water passages and a plurality of air tubes arranged between said water passages, each of said water passages having opposing walls formed by two strips of sheet metal which have their opposite longitudinal edges engaging one another and their walls intermediate of said edges spaced from each other, and each of said strips being provided at intervals with laterally projecting loops forming air tubes, and the air tubes of one of said strips being arranged in the space between similar air tubes of an adjacent strip.
2. A radiator core comprising a plurality of water passages and a plurality of air passages arranged between the water passages, each of said water passages being formed between two sheet metal strips provided with ofii-set flanges at their longitudinal edges which engage each other while their said edges are spaced apart, and each of said strips being provided at intervals with laterally projecting loops forming air tubes, each tube being integrally connected by webs on one of its longitudinal sides with one strip and provided on its opposite longitudinal side with a head, the ends of each head being provided with lugs, and the intermediate part thereof being provided with a recess, said lugs and recess engaging with the offset flanges and the wall of an adjacent strip.
A radiator core comprising a plurality of water passages and a plurality of air passages arranged between the water passages, each of said water passages being formed between two sheet metal strips provided with oil-set flanges at their longitudinal edges which engage each other while their walls intermediate of said edges are spaced apart, and each of said strips being provided at intervals with laterally projecting loops forming air tubes, the tubes of each strip being complete and arranged between similar tubes of an adjacent strip and forming therewith partial air tubes which alternate with the complete tubes.
A radiator core comprising a plurality of water passages and a plurality of air passages arranged between the water passages, each of said water passages being formed between two sheet metal strips provided with offset flanges at their longitudinal edges which engage each other while their walls intermediate of said edges are spaced apart, and each of said strips being i vided at intervals with laterally projecting loops forming air tubes, and the air tubes of one strip being arranged between the air tubes of an adjacent strip, and the air tubes of one strip having its end portion engaging with the corresponding end portube of an adjacent strip,
tions of an an while the intermediate parts of said all tubes are spaced apart to form transverse air passages therebetween.
In testimony whereof I, hereby aifix my signature.
JOHN M. FEDDERS.
US120608A 1926-07-06 1926-07-06 Radiator core Expired - Lifetime US1657463A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US120608A US1657463A (en) 1926-07-06 1926-07-06 Radiator core

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US120608A US1657463A (en) 1926-07-06 1926-07-06 Radiator core

Publications (1)

Publication Number Publication Date
US1657463A true US1657463A (en) 1928-01-31

Family

ID=22391417

Family Applications (1)

Application Number Title Priority Date Filing Date
US120608A Expired - Lifetime US1657463A (en) 1926-07-06 1926-07-06 Radiator core

Country Status (1)

Country Link
US (1) US1657463A (en)

Similar Documents

Publication Publication Date Title
EP0021651B1 (en) Louvred fins for heat exchangers
US2439208A (en) Heat exchanger
US3223153A (en) Fin and tube type heat exchanger
US2195259A (en) Condenser for mechanical refrigerators
US4789027A (en) Ribbed heat exchanger
US3397741A (en) Plate fin tube heat exchanger
CN204177261U (en) A kind of flat pipes of heat exchanger and micro-channel heat exchanger
US3380518A (en) Finned heat exchanger
JPH0263155B2 (en)
US3472316A (en) Layered heat exchanger with interlocking header plates
US3217798A (en) Heat exchanger
US3643735A (en) Fin and tube heat exchanger
US3734178A (en) Heat exchanger
JP4011694B2 (en) Plate fin type heat exchanger with knob
US1657463A (en) Radiator core
DE3760214D1 (en) Heat-exchanger, more particularly evaporator for refrigerant
US1799691A (en) Radiator construction
US1927079A (en) Heat convector
IT978955B (en) HEAT EXCHANGERS PARTICULARLY FOR VEHICLE RADIATORS
US1957703A (en) Radiator
US1675796A (en) Radiator
US2126736A (en) Radiator core structure
US1682327A (en) fedders
US2020957A (en) Radiator
US1851881A (en) Heat exchanging apparatus