US2646258A

US2646258A - Automobile heater

Info

Publication number: US2646258A
Application number: US123841A
Authority: US
Inventors: Phelps M Freer
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-10-27
Filing date: 1949-10-27
Publication date: 1953-07-21
Anticipated expiration: 1970-07-21

Description

July 21, 1953 FR 2,646,258

AUTOMOBILE HEATER Filed Oct. 27, 1949 2 Sheet s-Sheet 1 INVENTOR. l/ M nee/1' P. M. FREER AUTOMOBILE HEATER Jl lly 21, 1953 2 Sheets-Sheet 2 Filed Oct. 27, 1949 i7 INVENTOR.

7%22): vAZ' 7766/? yfi irra/m f Patented July 21, 1953 UNITED STATES PATENT OFFICE V Phelps M. Freer, Detroit, Mich. Application October 27, 1949, Serial No. 123,841-

6 Claims. (Cl. 257137) This invention relates to heat exchange devices and, in particular, to heaters cf the type that may be used in automobiles and the like.

It is an object of the invention to increase the heat transfer efficiency of heaters of the type described and thus reduce the size-capacity ratio and the cost of the heater unit.

Another object is to provide a heater that may be economically made from sheet metal parts.

These and other objects of the invention are accomplished by means of a heater construction in which the conduit or coil for the fluid heating medium is of sinuous shape and preferably made from originally flat, spaced, superposed sheets of metal secured together at theirside edges. The sinuous coil is placed in a sheet metal box that has bulges in the sides upon which the curved portions of the coil rest whereby the coil is fitted into and supported by the sides of the box. A

cover is yieldably attached to the box to-close the opening through which the coil is inserted and serves as a side thereof. Each of the sides of the box which is normal to the sides that support the coil is formed with bulges that are staggered with respect to the bulges in the opposite side and serve to direct air back and forth in sinuous passage from one loop to another of the coil. The coil is formed with projections and fins that serve to create turbulent air low and this may be further promoted by the use of irregularly surfaced divider plates between adjacent sections of the coil. The core formed by the box and coil may be encased at opposite walls by inlet and outlet manifolds and, if desired, a flow impeller may be secured to one of the manifolds to form a selfcontained heater unit. l

By virtue of the foregoing construction, the heater is endowed with an extremely large area of heat-conducting contact between air and coil. The use of fins on the coil serves also to transfer heat to the air by radiation. The turbulence provoking projections" and the fins tend to cause air flow thatremoves the boundary layer andrthe divider plate tends to prevent stratification, thus providing optimum conditions for the transfer of 1 heat from the heating liquid to the air. The turbulence' projections also increase the surface area of the coil and serve to create some turbulence in the heating liquid flowing therein. The net result of these and 'otherfeatures is to provide a 1 high rate of heat transfer in a small-size unitr Other objects and features of the invention will become apparent upon consideration of the ac-.

2 Fig. '4 is a section taken on line 4 4 of Fig. 2; Fig. 5 is an enlarged view of the structure contained with the circle 5 of Fig. 2; and Fig. 6 is a sectional view of a plug valve that may be used informing the'sinuous coil'of the invention.

The automobile heater of this invention has a sinuous thin-walled'heat exchange coil l for the passage of heating liquid from the radiator. It comprises a plurality of straight sections 3 (Fig. 4), each of which is joined at its ends to an adjacent straight section by a recurved section 5. The internal sinuous passage for fluid is designated by the reference numeral i. This coil is designedto give a high ratio of surface area to volume and therefore itswidth and its loop length (distance between oppositely disposed recurvatures 5) are substantially larger than its thickness. While the coil surfaces are illustrated as flat, they may be undulated or corrugated to increase the surface area and desirably affect fiuid flow. The coil is made of suitable corrosionresistant material, copper being the conventional material for this purpose. The coil may be formed from different types of raw stock, and it is not intended to limit the invention, in its broad aspects, to the history of manufacture of the coil. For example, the coil may be bent from tubing that is originally formed to the desired cross sectional shape. Again, it may be formed by flattening round tubing and then bending the product into sinuous shape Advantage is more read- I ily taken of certain detail features of the invention, however, .when'the' coil is formed from originally fiat sheet metal. It is possible to make the coil tubeflfr'om sheet metal in either of two ways, the-second of which is preferred and illustrated'herein, via. (1) by forming and folding a single sheet of metal and then securing its edges as bestindicated in Fig. 5. It will be recognized that generically the coil formed by either of these 'two methods may be described as one comprised of a pair of spaced superposed sheets having their side edges sealinglyinterconnected or secured together) The opposite faces or pieces I I of the coil each "have 'a multiplicity of outwardly extending. projections or bosses l3 pressed therein which are generally round in cross section. They serve to create turbulence in the air flowing by and thus to. cause some scrubbing of the boundary layer, and also increase the surface areaand cause turbulence in the heating fluid flowing through the coil. The coil pieces I I also have generally round inward projections iii that serve to maintain the y proper spacing between the pieces and which may thus engage similar projections on opposite coil pieces, as illustrated, or be of a length equal to the width of the passage so as to engage the flat face of the opposite piece. The projections I are sufficiently few in number so that they do not appreciably interfere with the flow of water through the passage 7, though it is desirable that they create some turbulence in liquid flowing through the coil. The upper open end of the coil I (Fig. 4) forms the outlet for water and is adapted to discharge it into a suitable hose by a length of pipe or tubing II that has a slot I9 therein registering with the end opening of the coil. The ends of the pieces II may be flanged at ZI and soldered to the surface of the tubin I'i, a indicated, to effectuate the desired watertight connection. The lower open end of the coil Iforms the inlet for water from the radiator and is provided in a similar manner with a pipe or tube 23.

The coil I may be manufactured by several methods, features of which obviously may be used in constructing the coil from various of the types of raw stock mentioned above. In one method straight dished pieces II with the projections formed therein of the developed length of the coil are separately bent into sinuous form, placed together, and the edges clamped and soldered. In another method, straight pieces of the developed length are joined together by soldering of the flanges 9 after the projections I3 and I5 have been formed therein but prior to bending into sinuous shape. The outlet and inlet tubes ii and 23 are preferably attached to the ends before bending. The sections of the pieces 5 I which are to form the outside of the curved sections 5 are desirably provided before soldering with outward- 1y pressed arcuate ribs 25 (Fig. 4) that extend the full width of the coil. The diameters or chords of these ribs expand during bending of the pieces into the curved section 5 to prevent flattening at those sections. As a further precaution against flattening and undesired restriction of passage I, the straight flat tube is preferably filled with water (or other substantially incompressible liquid) prior to bending into the sinuous form. This may be done by plugging both of the pipes I1 and 23. It is desirable that at least one of these plugs be in the form of a pressure relief cap 21, such as shown in Fig. 6. The cap 21 comprises a plug body 29 that is adapted to sealingly fit in the end of a pipe, as pipe II. The body has an aperture 3| which is enlarged to form a valve seat 33 and a spring chamber 35. The body is threaded to receive an apertured retainer 31 to bear upon a spring 39 that holds the ball II on the seat 33 with a desired and adjustable force. It is obvious that if at any time during the bending of the flat soldered pieces II excessive diminuation of volume of the passage I takes place, the ball II will be forced off its seat to relieve pressure in the passage and indicate that the bending process is proceeding in an improper manner. Before this takes place, however, the liquid in the coil, being substan tially incompressible, will serve to prevent restriction of the passage I.

7 Instead of forming the coil I by bending continuous developed lengths of the pieces II, a build-up procedure may be employed. In this method flat sections of a length that accommodates less than all of the curved sections 5 are bent and then joined with other sections to form the complete coil. For example, the coil may be built up from U-shaped sections that are provided at their ends with flanges, as indicated at A3 in Fig. 3. The flanges of enough sections are then soldered together to form the sinuous coil 2. In this method the spaced superposed sheets may be soldered together first and then bent, or Ibent first and then soldered together.

The coil i fits in a sheet metal box 35 and these two elements form the heater core. The box has five integral sides and the sixth and open side is closed by a cover :3? that has a flange that fits inside the box, as indicated at 49. The side walls 5| and 53 of the box that define the open side of the box have bulges or curved sections 55 therein that correspond to the curved sections 5 of the coil I. They, and also the top and bottom 5'! and 59 of the box, also have cylindrical enlargements III to receive the pipes I? and 23 on the coil I. If the cover 41 is removed from the box 45, the coil 5 can then be slipped into it, and the curved sections 5 nt in and on the bulges 55 which therefore serve to support the coil. The curved sections 55 may have inwardly pressed projections 63 therein to engage the coil I and facilitate this assembly.

Air is allowed to flow in a sinuous path through the coil I by outwardly curved sections 65 and 66 that are formed in the front wall 61 of the box and in the cover i? thatforrns the rear wall of the box. The curved sections '55 and 6B are adjacent the side flanges 9 of the coil and alternately place opposite sides of the straight coil sections 3 in communication with each other.

Air enters the core through an inlet 69 that is formed in the cover 31 and extends the width thereof and which registers with the air passage between the top two straight sections 3 of the coil. A similar opening II in the front wall 6'! adjacent the air passage between the bottom two straight sections 3 of the coil forms the outlet for air. Between the inlet and outlet, the air flows downwardly back and forth between the straight sections 3 of the coil I and between the curved front wall sections E35 and the curved rear cover sections $6. In the meantime, water or other heat-supplying medium flows upwardly from inlet pipe 23 in the coil pass-age I back and forth be tween the sides 5! and 53 of the core to the outlet pipe II.

The cover 47 has suitable apertures for the passage of pipes I? and 23. It is yieldably held in place on the box 45 by several pins 12 that extend through the box and may shoulder on the outside of the front wall 6? and have a weak coil spring I3 thereon that is pressed against the outside of the cover 4? by insertion of a cotter pin I4 through a suitable aperture in the pin. Inward movement of the cover i'I is prevented by the coil flanges 9. Alternate straight sections 3 that are staggered in opposite sides of the coil have the flanges 9 squared off or cut off on a straight edge. These straight edges bear against flat surfaces on the front wall 5? and cover 41 between the curved sections 65 and Ed to determine the minimum overall front-to-rear dimension of the core which is ieldably maintained by the springs I3.

The front and rear of the core are enclosed by headers or manifolds 1-5 and I7, respectively. These, like the box 55 and cover M, are preferably pressed from sheet steel and are adapted to receive the pipes II and 23. They shoulder on the box and cover as indicated at iii and are generically similar to covers and thus fit snugly on the box. The rear or inlet manifold 11 has a length of arched spring: wireiillsecuredibya pin or rivetj 83"to'the inside of its rear wall which bears upon the-cover t? "and stresses the parts of the heater so as to prevent relative movement and rattling. Whenspring 83 is used, the pins '12 and coilisprings 13 may be eliminated. The

manifolds are forced on their shouldered seats 19 .by bolts 85 that extend through the entire assemblyof manifoldsand core. ir'I-he :rear manifold is apertured at..8'i=to allowaircto flow to the inlet 69. The front manifoldhas anv opening 89 to allow air to flow fromthe outletfl i.

:.An impeller may .beiused to "induce air flow through the present heater and-may be placed on theinlet side to floweirthrough, but prefer- .abl is placed on the outlet side' thereof-to estab- .lish.a negative air pressure which results-in more effective air flow, by the coil I. This maybeaccomplished by providingthe outlet manifoldit with a collar Sisurrountiing the opening 89 and suspending therein a suitable flow-inducing fan 93. a

.It'is evident from .the structure already described that by providing a counter sinuous flow of-"air 'and-h'eatingwater in conjunction with a T" fiat surfaced sinuous coila maximum surface for heat conduction is achieved. The efficiency is increased further by providing the flanges 9 i the coil I which fit'in the curved sectionsCb and 66 with fins, as'best illustrated in Fig'l'b. The

fins not'only furnishheat by radiation, but also fs'erve'to' increasejthe emcie'ncy of heat transfer I 1. heat exchanger comprising spaced super- -posed sheets xsealingly secured together at their side-ledges and of sinuous .form providing a sinu-' ous coil for heating fluid, said sheets having out- .ward. turbulence-provoking bosses thereon, said Isheetshaving inward Jbossesthereon, portions of the side edges :of said sheets being. inclined to theplane of the sheets to form radiation and turbulence-provoking; fins, an inlet pipe for the .coillcommunicatively secured to one end of the sheets, an outletpipe-for the coil communica- :tiv.el-y secured to, the other end of the sheets a box having-outward bulgesina pair of opposite ;sides that-conform to, and receive and support -the.redurvitiesgot-the sinuous coil, said box sides having inwardprojections therein engaging the Surfaceof the coil, said box having an opening in. aside normal to the sideswhich sup-port the sinuous coil wherebythe coil may be insertedin the box, a cover for said opening, .meansyieldably {pressing the cover against the secured side edges of the "sheets" and forcing opposite secured side edges ofithe sheets against the side of thebox opposite the. cover, -said -,cov er,-; box, and coil definingya core, means providing inlet and outlet openings inthe walls of the core,- bulges in the cover and the side opposite the cover for directingfiuid: to be'l eatBdi-r-Q theinlet to the outlet by conduction 'bypromoting turbulent flow of] the air. Thefinsrareillustratedas being formed in twodifierent ways. In one,th e double thickness of metal forming the soldered or brazed flange 9 is extended-beyondthepreviously mentioned straight edge flanges and then slit and bent alternatelyijn opposite directions to form the fins 95 that are radial with respect to the curved section-'6 but spaced therefrom so as to attached alternately to the side walls 5! and 53- of the box by means offianges [0! at positions midway between straight sections of the coil l. The plates have corrugations or ribs I63 transverse to the air flow pressed therein, which extend out opposite sides thereofto provide rigidity and by varying the size of the air passage create an aspirator effect that produces turbulence in the air flowing through the core. It is to be noted that'the plates 93 provide these beneficial effects without materially reducing the size of the passage through which the air fiows. Obviously, the aspirator effect can also be produced by making the coil surfaces of undulatory form.

The box ,5, cover 47, and manifolds and i1 may be employed as a self-contained heater and secured to the firewall of a vehicle by brackets 1 H), as illustrated in Fig, 1.

Modifications may obviously" be made in. the

specific structure herein described. without departing from the spirit of the invention.

What is claimed is:

in -a sinuous path over the coil back and forth between the cover and the side opposite, flow divider. plates having turbulence provoking ribs thereon located betweenadjacentsections of the coil, mamfold cover means f tting the box over the inlet andoutlet openings for the fluid to be heated, spring means assooiate d with the mamfold cover means applyingyieldable pressure to the cover .for the box, said manifold cover means having inlet and outletopenings incommunication with the inlet and outlet openings in the core, and impeller means for actuating flow of fluid to be heated, saidimpeller means being located at" theioutlet of. the core to establish negative pr'essure inthe core, said impeller means .being supported'upon the manifold cover means.

2. An' auto heater comprising a tube having a width substantially greater than its thickness and of sinuous form providing a sinuous coil for heatsupport the recurvities of the sinuous coil, said ing fluid, a box having outward bulges in a pair.

of opposite sides that conform to and receive and box having a removable-side normal to the sides which support the sinuous coil whereby the coil may be inserted in the box by movement transverse to the length of the coil passes, means providing inlet and outlet openings in the box, and bulges in the removable side and the side opposite the removable side communicating with the spaces between the coil passes for directing fluid-to be heated from the inlet opening to the outlet opening in a sinuous path over the coil back and forth between the removable side and a a cover for said opening and forming a side of the box, means providing inlet and outlet openings in'the box, bulges in the cover and the side opposite the cover communicating with the spaces between the coil passes for directing fluid to be heated from the inlet opening to the Outlet opening in a sinuous path over the coil back and forth between the cover and the side opposite, and manifold cover means fitting the box over the inlet and outlet openings for the fluid to be heated.

4. An auto heater comprising a tube having a width substantially greater than its thickness and of sinuous form providing a sinuous coil for heating fluid, a box having outward bulges in a pair of opposite sides that conformto and receive and support the recurvities of the sinuous coil, said box having a removable side normal to the sides which support the sinuous coil whereby the coil may be inserted in the box by movement transverse to the length of the coil passes, means providing inlet and outlet openings in the box, and bulges in the removable side and the side opposite the removable side communicating with the spaces between the coil passes for directing fluid to be heated from the inlet opening to the outlet opening in a sinuous path over the coil back and forth between the movable side and the side opposite, and impeller means for actuating flow of fluid to be heated.

5. An auto heater comprising a tube having a width substantially greater than its thickness and of sinuous form providing a sinuous coil for heating fluid, a box having outward bulges in a pair of opposite sides that conform to and'receive and support the recurvities of the sinuous coil, said box having a movable side normal to the sides which support the sinuous coil whereby the coil may be inserted in the box by movement transverse to the length of the coil passes, means providing inlet and outlet openings in the box, bulges in the movable side and the side opposite the movable side communicating with the spaces between the coil passes for directing fluid to be heated from the inlet opening to the outlet opening in a sinuous path over the coil back and forth between the movable side and the side opposite,

and impeller means for actuating flow of fluid to be heated, said impeller means being located at the outlet of the core to establish negative pressure in the core.

6. An auto heater comprising a tube having a width substantially greater than its thickness and of sinuous form providing a sinuous coil for heating fluid, a box having outward bulges in a pair of opposite sides that conform to and receive and support the recurvities of the sinuous coil, said box having a movable side normal to the sides which support the sinuous coil whereby the coil may be inserted in the box, means providing inlet and outlet openings in the box, and bulges in the removable side and the side oposite the removable side communicating with the spaces between the coil passes for directing fluid to be heated from the inlet opening to the outlet opening in a sinuous path over the coil back and forth between the removable side and the side opposite, and

resilient means for holding the removable side in place in the box.

- PHELPS M. FREE-R.

Number Name Date 154,368 Bon Aug. 25, 1874 203,842 Leland May 21, 1878 953,252 Brinkman Mar. 29-, 1910 1,578,830 Jones et al Mar. 20, 1926 1,618,279 Fedders Feb. 22, 1927 1,788,447 Buck Jan. 13, 1931 1,992,835 Newman Feb. 26, 1935 2,008,255 Larkin July 16, 1935 2,022,173 Alexander Nov. 26, 1935 2,028,456 Karmazin Jan. 21, 1936 2,107,031 Evans Feb. 1, 1938 2,211,813 Franco-Ferreira Aug. 20, 1940 2,217,799 Giesler Oct. 15, 1940 2,337,584 Baker Dec. 28, 1943 2,444,824

Hall July 6, 1948