US2786653A - Heat exchanger attachment for hot water heaters - Google Patents

Description

March 26, 1957 J. A. MARTIN 2,785,653

HEAT EXCHANGER ATTACHMENT FOR HOT WATER HEATERS Filed Feb. 4, 1953 IN V EN TOR.

8 2/ J5/m A. MART/N ATTORNEYS 2,786,653 1C3 Patented Mar. 26, 1

HEAT EXCHANGER ATTACHMENT FOR HOT WATER HEATERS John A. Martin, Minneapolis, Minn.

Application February 4, 1953, Serial No. 335,095

4 Claims. (Cl. 257-137) This invention relates generally to an attachment for converting conventional hot water heaters to efiicient space heaters for small farm buildings and the like and is an improvement on my co-pending application, Serial No. 294,825, filed June 21, 1952, and entitled, Combination Hot Water and Space Heating Unit.

While the attachment for converting hot water heaters to efiicient space heaters disclosed in my above identified co-pending application has proved very successful and efficient, the attachment conversion device disclosed in the instant application has proved to be considerably more eflicient and is more universally applicable to a wide variety of different styled conventional hot water heaters.

It is an object of my present invention to provide a novel and highly efiicient heat exchanger attachment for conventional hot water heaters particularly constructed to maintain close heat transfer association between the air traveling through the heat exchange chamber and the heat exchange surface of the hot water tank.

It is another object to provide an attachment for conventional hot water heater tops to convert the same to an efficient heat exchanger and space heating unit which provides a heat exchange chamber overlying the top of the tank in direct contact therewith and confined to the area of the upper portion of the tank surface while providing a tortuous path particularly constructed to maintain close heat transfer association between the circulating air and the heat exchange surface of the tank exposed thereto.

More specifically, it is an object to provide a plurality of substantially concentric bafiles having circulating openings formed in the lower edge portions thereof adjacent the tank top to permit air to travel from one passage to another adjacent the top surface of the hot water heater tank.

These and other objects and advantages of this invention will more fully appear from the following description made in connection with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views, and in which:

Fig. l is an exploded side elevational view of my new heat exchanger;

Fig. 2 is a bottom perspective view of the heat exchanger attachment;

Fig. 3 is a central vertical sectional view showing the heat exchanger mounted in operative position on a hot water heater tank top; and

Fig. 4 is a schematic view showing diagrammatically the heat exchange passages and by directional arrows the air flow circulation paths therethrough.

As illustrated in the accompanying drawings, I show a conventional hot water heater tank 6 surrounded on the sides by an annular insulation jacket 7 and an outside protective casing 8. The tank 6 has a central upstanding conduit 9 and is of generally conventional design.

An annular casing member 10 is mounted at the top of the protective casing 8 and has an abutment collar 11 fixed thereto in upwardly spaced relation to the lower edge thereof. The lower depending edge portion disposed below the collar 11 is of slightly smaller diameter than the upper portion of easing 8 and is received within said upper casing portion 8 with the collar abutting the top peripheral edge thereof. A pair of openings 12 and 13 are formed on opposite sides of the annular casing member 10 and a deflector hood 13a is disposed outside the discharge opening 13. A shell 14 having a depending annular skirt 14a of substantially the same diameter as the upper portion of the tank 6 to fit therearound, as best shown in Fig. 3, is provided and is positioned within the annular casing member 10 and defines a heat exchanger chamber under said shell 14. Inlet and outlet openings are formed in the upper dome-shaped top of shell 14 and conduits 15 and 16 are respectively connected therewith to interconnect said openings with the respective openings 12 and 13 formed through the easing 10. Suitable sealing pads 15a and 16a are respectively provided on the outer ends of conduits 15 and 16 to sealingly engage the portions of the casing 10 respectively surrounding openings 12 and 13.

The chamber defined within the shell 14 is subdivided by a pair of concentrically disposed bafiles in the form of cylindrical segments 17 and 18 providing an annular passage therebetween with the inner segment 18 defining a central discharge chamber therewithin. The lower edges of the baflles 17 and 18 have serrated portions, as best shown in Figs. 2 and 3, and the lower edges of said batlles are positioned relative to each other and to the skirt 14a of shell 14 to engage the outside surface of the top of tank 6, as best shown in Fig. 3. The portion of baffle 17 disposed in inwardly opposed relation to the inlet conduit 15 has a straight lower edge which remains in substantially sealed contact throughout its length with the tank top and divides the air flowing in through said conduit 15, as indicated by the arrows in Fig. 4. The air travels around the outer annular passage in contact with the tank top and passes inwardly therefrom through the serrated side portions of said baffle 17. The inner baffle 18 is serrated around the entire lower periperal edge thereof and maintains contact between the flowing air and the top surface of the tank as said air flows through the openings between the teeth of the serrations into the central discharge chamber. The air is forced to flow back behind the imperforate portion of bafile 17 since the circumference of thebafile 18 is substantially shorter than the circumference of the bafile 17 and the air flowing through the side ser' rated portions of bafiie 17 has a greater volume than can pass through only the lateral side portions of the inner baffle 18.

A pair of spaced delivery guiding plates 19 are fixed between the spaced end extremities of the baffles 17 and 18 with the inner ends thereof disposed adjacent the ends of said inner cylindrical segment 18, as best shown in Fig. 2, to form a discharge passage communicating with the discharge conduit 16 and forcing the air to flow through the desired tortuous path in contact with the top surface of tank 6 to remove heat therefrom with a high degree of eificiency.

A blower 20 is mounted'on the outside of easing section 10 and delivers air into the heat exchanger chamber in contact with the top of tank 6, and said air is discharged through the outlet conduit 16 after being warmed by contact with said top of tank 6. Suitable insulation is provided above the shell 14 and is designated by the numeral 21. A casing cover 22 may be provided in overlying relation to said insulation and, in the form shown, this casing cover is the same cover normally used on the conventional hot water heaters and has a depending attachment flange portion adapted to receive the upper 3 marginal portion of the annular casing member 10, as best shown in Fig. 3.

The following is a description of the operation of my improved heat exchanger attachment for converting hot Water heaters to space heating units. After the conventional cover 22 and insulation has been removed from the hot water heater, the entire shell with the cylindrical baflles fixed therein is placed on the top of tank 6 in direct contact therewith, with the depending skirt 14a engaging the outer peripheral portion of said tank top, and forming a heat exchanging chamber thereabove. The blower 20 draws air from the room and delivers the same into said chamber through inlet conduit 15. The air initially is directed against the imperfonate section of the outer cylindrical baffle 17 and the flow is divided and passes around the sides of the top of tank 6 within the area confined by the depending skirt portion 14a and is forced through the openings of the serrated lower edge of the side portions of said bafile 17 into the intermediate annular heat exchanging chamber between the two substantially cylindrical bafiies 17 and 13. Due to the fact that the periphery of the inner bafile 13 is substantially shorter than the periphery of the outer baffle 17 and therefore the open area through which the air must of necessity pass, through the serrations formed in the lower edge of said inner bafile 13, is substantially less adjacent the sideportions thereof, the air is thus caused to circulate around the entire outer periphery of said inner bafile 18 and finally pass into the discharge chamber in contact with the tank top and out through the discharge conduit 16 and is deflected downwardly by the deflector plate 13a.

It will be seen that l have provided a relatively simple, yet highly eflicient, attachment for conventional hot water heaters to convert the same into a heat exchanger for efficiently heating a room such as a milk house or the like. The communication openings formed by the serrations around the side portions of the outer baflle 17 and the serrations formed in the lower edge portion of the inner baffle 18 cause the air to fiow from one chamber to another in contact with the tank top to more effectively remove the heat therefrom.

It will, of course, be understood that various changes may be made in the form, details, arrangement, and proportions of the parts without departing from the scope of this invention which, generally stated, consists in the matter shown and described herein and set forth in the appended claims.

What I claim is:

l. A heater exchanger attachment for a hot water portions with the upper edges thereof in substantially sealed contact relation with the inside surface of the cover shell and positioned relative to each other in a manner to provide a plurality of heat transfer passages in heat exchange contact with the tank top, the lower marginal edge portions of said baflie members having a plurality of: openings formed therein to permit circulation of the air between said passages and maintain contact between the circulating air and the heat exchange surface of the hot water heater tank top, said cover shell having inlet and outlet means formed therein in communication with said chamber, and means for causing circulation of air through the passages in said chamber.

2. A heat exchanger unit comprising a generally domeshuped heat exchange surface with a cover shell disposed in spaced relation to the heat exchange surface with the outer portion thereof sealingly interconnected with said surface to form a heat exchange chamber between said shell and said surface, a plurality of generally concentric baffles of segmental cylindrical shape disposed in substantially sealed contact at their upper edges with said shell and extending downwardly therefrom to engage portions of the heat exchange surface and form a plurality of heat exchange passages in contact with said heat exchange surface, said bafiles extending the full distance between shell and said surface but having openings only in the lower marginal edge portions thereof to afford communication between said passages whereby turbulence of the flowing air is produced by the openings in said baffles extending only a part of the distance 'between the shell and the heat exchange surface, said shell having laterally disposed inlet and outlet openings communicating with said passages but communicating with each other only through said passages, and means for causing circu lation of air through said openings and said passages.

3. The structure set forth in claim 2 and the edges of said battles in contact with said heat exchange surface being serrated to provide the intercommunication openings between said passages adjacent the heat exchange surface.

4. The structure set forth in claim 2 and said serrated openings being of greater dimension adjacent said heat exchange surface than they are remote therefrom to increase the heat exchange contact of the flowing air with said surface.

References Cited in the file of this patent UNITED STATES PATENTS 163,443 Barrows May 18, 1875 282,567 Richardson Aug. 7, 1883 312,678 Vaughan Feb. 24, 1885 336,392 Converse Feb. 16, 1886 l,0l3,050 Orr Dec. 26, 1911 2,175,307 Peck Oct. 10, 1939 2,244,831 Drichta et a1. June 10, 1941

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