US3732849A

US3732849A - Miniature heat exchanger

Info

Publication number: US3732849A
Application number: US00167763A
Authority: US
Inventors: E Coley; J Dutfield
Original assignee: American Standard Inc
Current assignee: Trane US Inc
Priority date: 1971-07-30
Filing date: 1971-07-30
Publication date: 1973-05-15
Anticipated expiration: 1990-05-15

Abstract

Covers a heat exchange element for use in a boiler for central heating systems or the like. The heat exchange element includes a boiler section having a passage for water or for any other fluid medium, the passage extending longitudinally and horizontally through the section. The water passage section has a plurality of closely arranged laterally protruding fins formed integrally with the walls of the water passage and they are positioned above horizontally disposed burners which may be supplied with gas.

Description

United States atent 1 Coley et al.

[ 1 3,732,49 51 May 15,1973

[54] MINIATURE HEAT EXCHANGER [75] Inventors: Eric Harry: Coley, Skidby, England;

James Dutfield, Brussels, Belgium [73] Assignee: American Standard Inc., New York,

[22] Filed: July 30, 1971 [21] App]. No.: 167,763

[52] U.S. Cl. ..122/367 C, 165/181 [51] Int. Cl ..F22b 37/12 [58] Field of Search ..165/130, 131,181;

[56] References Cited UNITED STATES PATENTS 10/1944 Wolfetal ..122/367 3/1945 Morrow ..122/367 2,739,576 3/1956 Ricardo ..122/233 FOREIGN PATENTS OR APPLICATIONS 512,994 10/1939 Great Britain ..122/367 Primary ExaminerKenneth W. Sprague Attorney'.lefferson Ehrlich et a1.

[57] ABSTRACT Covers a heat exchange element for use in a boiler for central heating systems or the like. The heat exchange element includes a boiler section having a passage for water or for any other fluid medium, the passage extending longitudinally and horizontally through the section. The water passage section has a plurality of closely arranged laterally protruding fins formed integrally with the walls of the water passage and they are positioned above horizontally disposed burners which may be supplied with gas.

7 Claims, 4 Drawing Figures PATENTED RAY I 51975 SHEET 1 OF 3 IN VliN'IOA S,

COLEY ERIC H y JAMES DUTFIELD WW4 ATTORNEY Ila :DLLJQD IN VENTORS,

COLEY DUTFIELD ATTORNEY ERIC H. BY JAMES PATEMEUHAYISIQYS 3 732,849

SHEET 3 0F 3 F G INVENTORS,

ERIC H. COLEY BY JAMES DUTFIELD ATTORNEY MINIATURE HEAT EXCHANGER This invention relates to boilers such as are employed in central heating systems, and, more particularly, to heat exchange elements for such boilers. Still more particularly, this invention relates 'to miniature boilers and also to miniature heat exchange elements for such miniature boilers.

In accordance with this invention, there is provided, in or for a boiler, a heat exchange element comprising a horizontal section having a passage extending longitudinally of the section between end plates formed integrally with the passage walls, said passage being vertically elongated throughout the length of the section and having closely spaced laterally protruding fins externally thereof. Such fins, in the assembled boiler or heat exchange element, will be located above horizontally disposed gas burners of the composite boiler.

For a better and clearer understanding of the invention, an embodiment thereof will now be described by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a side view of a heat exchange element shown partly in vertical section along the line 1-1 of FIG. 2;

FIG. 2 is an end view of the heat exchange element corresponding to FIG. 1, the element being viewed from the left of FIG. 1;

FIG. 3 is plan view, partly in section, along the line III-III of FIG. I; and

FIG. 4 is a front elevational view, partly in section, of a boiler incorporating a heat exchange element substantially in accordance with the embodiment of FIGS. 1 to 3.

Throughout the drawing the same or similar reference characters will be employed to designate the same or similar parts wherever they may occur throughout the drawing.

In order to present a more comprehensive view and understanding of the miniaturized components characteristically employed in this invention, some of the possible dimensions of the components of an exemplary boiler section will b indicated merely for illustration and explanation. Notwithstanding the reference to the dimensions of such components, the more important parameters will necessarily be the ratios of the several sizes of the several components.

The heat exchange element illustrated in FIGS. 1 to 3 comprises a cast iron boiler section 1 (see FIG. 2) having a water passage 2 extending longitudinally and horizontally of the section between its end plates 3 and 4 (see FIG. 1), the passage 2 forming the waterway of the section. In use, the section is intended to be arranged with its water passage 2 extending horizontally and, notwithstanding the height thereof, the section is accordingly referred to herein as a horizontal section.

The waterway passage 2 is of substantially oblong and of substantially rectangular shape in its crosssection as viewed in FIG. 2, the water passage being defined by

opposite side walls

5, 6, a top wall 7 and a curved bottom wall 8. The water passage 2 is thus of vertically elongated form, the height of the passage 2 being approximately somewhere near or between eight or none times the width thereof, and the horizontal length of the passage being approximately about twice the height.

The

end plates

3, 4, which are preferably cast integrally. with the walls of the passage 2, are substantially rectangular in shape (see FIG. 2) and are each formed with upper and lower ports 9, 10 for connection to inlet and outlet pipes, respectively, of a hot water central heating installation. The upper hole or port 9 in end plate 3 is surrounded by a flat bolting-on flange face 1 1 formed with two internally screw-threaded holes or ports 12 for receiving bolts of a suitable pipe union to be secured to the boiler section 1. The lower hole or port 10 in end plate 3 is internally screw-threaded to receive an externally threaded pipe connection. In the boiler section 1 illustrated, the lower hole or port 10 in end plate 4 (see FIG. 1) has bolting-on flange 11a (shown in dotted lines in FIG. 2) and corresponding screw-threaded holes 12, while the upper hole or port 9 in end plate 4 is internally screw-threaded for the reception of an externally threaded pipe connection. It will, of course, be understood that the upper and lower holes or ports in each end plate may both be provided with bolting-on flanges such as those shown and described.

The waterway passage 2 is also provided internally with longitudinally spaced pairs of upper and lower strengthening

webs

13,14. The

side walls

5, 6 of the passage 2 are also cast integrally with a plurality of laterally outwardly extending closely spaced fins 15, these having their faces vertically disposed and corresponding substantially in shape to the end plates but being somewhat smaller in lateral extent. Moreover, the fins 15 have lower edges 16 which may preferably be inclined at an angle of approximately 45 to the vertical, as may be seen more clearly in FIG. 2. The boiler section 1 is also formed integrally, substantially mid-way along its length, with reenforcing fins 17. These reenforcing fins 17 are of substantially the same lateral width as the

end plates

3, 4 and are of a thickness substantially double that of the other fins 15 for providing additional strength and additional heat conductivity.

The boiler of this invention, as illustrated in FIG. 4, is especially suitable for use in a domestic hot water central heating installation. The boiler comprises a sheet metal back plate which is designated 18 but is not specifically shown, to which a supporting frame 19 is secured. The frame 19 includes side plates, only one of which is shown at 20, between which side plates a horizontal boiler section 21 is mounted. The boiler section.

21 is similar or substantially identical to that previously described with respect to FIGS. 1 to 3, but it may have an end plate 22 provided with upper and

lower boltingon flanges

54, 53. The lower flange 53 has connected thereto a pipe union 23 forming a water inlet and the upper flange 54 has connected to it a pipe union 24 forming a water outlet.

Below the horizontal boiler section 21 there extends, at each side, a horizontal gas-bumer 25, the burner section also being mounted between the side plates (only one of which is shown and designated 20) and being connected to a gas supply through appropriate controls indicated generally at 26.

Cover plates

27 and 28 are provided for both the boiler section 21 and the gas burners 25 respectively.

In the water pipe line to or from the boiler section 21, there is arranged pump means (not shown) for forcing and pressurizing the water to be fed through the horizontal passage of the boiler section 21 to be heated to a sufficient or predetermined temperature. In use, the pump insures a continuous flow of water under pressure through the horizontal passage. The heatexchange surfaces provided by the multiplicity of parallel fins at opposite sides of the water passage 2 serve to insure satisfactory and efficient heating of the water in the water passage by the burning gases as the water passes through the finned boiler section 21 and thereaft'er passes through the external space to be heated.

The gas burners are spaced below the base of the boiler section 21 to permit an efficient heating of the finned surfaces by the upward movement of the flue gases, the spacing in the present embodiment being equivalent to almost one-half of the overall height of the heat exchange element of FIGS. 1 to 3. The arrangement incorporating the relatively narrow but elongated waterway passage 2 and the construction of fins 15 at both sides of the waterway passage 2 develop a high heating output to the water of the passageway 2 of the boiler section notwithstanding its relatively small or miniaturized dimensions.

In the use of the boiler sections 1 or 21, there is a relatively high temperature difference between the laterally outer tips of the fins l5 and the roots thereof nearest the walls of the water passage 2. With a view to counteracting or reducing the stresses that may result from this high temperature difference, substantially horizontal saw-cuts or gaps or other slots in the fins 15 may be provided along each side of the section. These saw-cuts or gaps or other slots 30 may extend transversely of the fins 15, as shown in FIG. 2, and such slots may extend to a depth of, for example, approximately two-thirds the width of the fins 15, as also shown in FIG. 2.

It will be appreciated that the arrangement shown in FIG. 4 constitutes only one example of the mode of use of the horizontal heat exchange section of this invention. A plurality of similar horizontal sections may be arranged in series or in parallel, as desired, to increase the overall heating capacity by any amount. Moreover, the multiplicity of horizontal heat exchange sections, whether arranged in series or in parallel, may readily be incorporated in wall-mounted boilers and other boiler constructions and such boilers and constructions may embody, as a composite unit, both a boiler proper and a water reservoir tank for providing a domestic hot water supply.

The fins 15 at each side of the water passage 2 of the heat exchange element are relatively closely spaced and extend outwardly over sufficient distances so as to provide relatively large heat conducting surfaces. Moreover, the fins 15 extend over substantially the whole height of the internal passageway. At each side, each of the fins 15 has a lateral extend or dimension of almost double the internal width of the water passage 2. Thus, in a heat exchange element of about cm. in length, with

end plates

3 and 4 of approximately l7.5cm. in height and l l.5cm. in width, positioned as indicated in the drawing, the internal dimensions of the waterway passage 2 may be about 16cm. in height and 2cm. in width. Also, the fins 15 corresponding in height to the

end plates

3, 4 may have, at each side, a lateral extent or dimension of about 3.8cm., a mean thickness of about 0.3cm., and a mean spacing of about 0.5cm. The heat exchange element may be made longer or shorter than that shown in the drawings or described above. Moreover, the section may be cast in spheroidal graphite iron which is of greater ductility and strength than normal cast iron.

The boiler of this invention, when equipped with one or more heat exchange elements or sections designated 1 or 21, constitutes an efficient, low cost, gas fired, natural draft, balanced flue boiler. Such a boiler is especially adaptable for wall-hung installations on an outside wall. In one form of construction, the overall cabinet dimensions may be, for example, about 600 mm. (23 5/8) in height, 500 mm. (21 5/8") in width, and 300 mm. (11 13/16") in depth.

While this invention has been shown and described in certain particular arrangements merely for illustration and explanation and while certain particular dimensions and proportions have been recited for aiding in understanding the significant parameters of the miniatun'zed heat exchange element of this invention and of the boiler in which such element is embodied, it should be clearly understood that this invention may be embodied in other and widely varied organizations without departing from the spirit and scope of this invention.

What is claimed is:

l. A heat exchange element for a boiler having two side walls and front and rear walls, comprising a single substantially horizontal walled water passage extending substantially-throughout the horizontal length between the side walls of the element and extending substantially over the height of the element but of a width substantially equal to about one eighth of the height of the element, the water passage having a substantially rectangular cross-section, the side walls of which are substantially uniform throughout its horizontal length, a plurality of substantially flat relatively thin parallel closely spaced fins integrally formed with, and extending outwardly from, and perpendicular to, each of the side walls of the water passage substantially over a distance reaching substantially to the outer side walls of the element, and a parallel re-inforcing fin having a means thickness about twice that of each of the first mentioned fins and located substantially midway between the side walls of the element.

2. A heat exchange element for a boiler having two side walls and front and rear walls, comprising a horizontal, walled water passage extending substantially throughout the horizontal length between the side walls of the element but of a width substantially equal to about one eighth of the height of the element, a plurality of substantially flat parallel closely spaced fins integrally formed with, and extending outwardly from, and perpendicularto, each of the side walls of the water passage substantially over a distance reaching to the outer side walls of the element, and reenforcing fins paralleling the first mentioned fins and having a mean thickness about twice that of each of the first mentioned fins.

3. A heat exchange element for a boiler according to claim 2 in which each of the fins is provided with a horizontal slot extending laterally for about two thirds of the width of each fin, each slot being provided about midway between the top and bottom of the element.

4. A heat exchange element according to claim 3 in which each of the fins has its bottom end tapered along a line about 45 with respect to the vertical dimension of the water passageway.

5. A heat exchange element according to claim 4 in which each side wall of the water passage is provided with a plurality of horizontal webs integrally formed with the respective walls for reenforcing said walls.

-- mitted, the height of the walled water passage heft-rig about one half of the length of the element, the width of the water passage being about one-eighth of the height of the heat exchange element, the heat exchange element including a plurality of flat parallel closely spaced fins integrally fonned with the walls of the water passage and extending outwardly and perpendicularly from both sides of the walls of the water passage substantially to the walls of the heat exchange element, the heat exchange element also including reenforcing fins paralleling the other fins and of greater thickness than the other fins, each of the fins being provided with a horizontal slot extending over about two-thirds of the width of each of the fins and positioned vertically about midway between the top and bottom of the element, the inner walls of the water passage being provided with a series of horizontal webs integrally formed with the walls of the water passage for reenforcing said walls.

7. A boiler for a central heating system or the like according to claim 6, which includes a plurality of heat exchange elements combined for increasing the capacity for heating the water flowing through the water passages of the heat exchange elements.

Claims

1. A heat exchange element for a boiler having two side walls and front and rear walls, comprising a single substantially horizontal walled water passage extending substantially throughout the horizontal length between the side walls of the element and extending substantially over the height of the element but of a width substantially equal to about one eighth of the height of the element, the water passage having a substantially rectangular cross-section, the side walls of which are substantially uniform throughout its horizontal length, a plurality of substantially flat relatively thin parallel closely spaced fins integrally formed with, and extending outwardly from, and perpendicular to, each of the side walls of the water passage substantially over a distance reaching substantially to the outer side walls of the element, and a parallel re-inforcing fin having a means thickness about twice that of each of the first mentioned fins and located substantially midway between the side walls of the element.

2. A heat exchange element for a boiler having two side walls and front and rear walls, comprising a horizontal, walled water passage extending substantially throughout the horizontal length between the side walls of the element but of a width substantially equal to about one eighth of the height of the element, a plurality of substantially flat parallel closely spaced fins integrally formed with, and extending outwardly from, and perpendicular to, each of the side walls of the water passage substantially over a distance reaching to the outer side walls of the element, and reenforcing fins paralleling the first mentioned fins and having a mean thickness about twice that of each of the first mentioned fins.

4. A heat exchange element according to claim 3 in which each of the fins has its bottom end tapered along a line about 45* with respect to the vertical dimension of the water passageway.

6. A boiler for a central heating system or the like, comprising a horizontal heat exchange element, a gas burner spaced below the heat exchange element and positioned substantially parallel with the heat exchange element, means for supplying to the heat exchange element pressurized water to be heated, the heat exchange element extending substantially throughout the length of the boiler and including a water passage having walls between which the supplied pressurized water is transmitted, the height of the walled water passage being about one half of the length of the element, the width of the water passage being about one-eighth of the height of the heat exchange element, the heat exchange element including a plurality of flat parallel closely spaced fins integrally formed with the walls of the water passage and extending outwardly and perpendicularly from both sides of the walls of the water passage substantially to the walls of the heat exchange element, the heat exchange element also including reenforcing fins paralleling the other fins and of greater thickness than the other fins, each of the fins being provided with a horizontal slot extending over about two-thirds of the width of each of the fins and positioned vertically about midway between the top and bottom of the element, the inner walls of the water passage being provided with a series of horizontal webs integrally formed with the walls of the water passage for reenforcing said walls.