US2701554A - External flue water heater - Google Patents

Description

Feb..8, 1955 R s, RHEEM ETAL 2,701,554

EXTERNAL FLUE WATER HEATER Filed Sept. 11, 1950 5 Sheets-Sheet 2 ICHAPD s. RHEEM a STANTON 1.. mRa/wuaH,

- INVENTORS. HUEB/VER, BEE'HLER, WORREL,

HERZ/G 8 CALDWELL, By ATTORNEYS.

Feb. 8, 1955 s. RHEEM VET AL. 2,701,554

EXTERNAL FLUE WATER HEATER Filed Sept. 11, 1950 5 Shets-Sheet 3 STANTON L. V4 RBROUGH,

IN V EN TORS.

HUEBNER. BEEHLER, WORREL,

HERZ/G 8 CALDWELL ATTORNEYS.

nited States Patent EXTERNAL FLUE WATER HEATER Richard S. Rheem, New York, N. Y., and Stanton L. Yarbrough, East Pasadena, Calif., assignors to Rheem Manufacturing Company, Richmond, Calif., 21 corporation of California Application September 11, 1950, Serial No. 184,218

2 Claims. (Cl. 122-19) This invention relates to water heaters and more particularly to water heaters of the outside flue type, having a burner at the bottom of the water tank and a series of fiues spaced around the tank up which the hot gases pass, transferring heat into the water in the tank.

The principal object of this invention is to improve and simplify the construction of such heaters so as to enhance efiiciency and increase durability for a given cost of construction.

It is a more particular object of this invention to improve the design and configuration of the water tank of an exteral fiue heater so as to simplify and strengthen its fabrication.

It is another object of this invention to design a heater of the outside flue type in which special problems in the construction of the water tank are obviated through suitable configuration of the heater.

Other and further objects and advantages will be more apparent from the drawings and specifications relative thereto.

In prior art heaters of the outside flue type, it has been necessary, in the past, to design a special fluted end plate for the water tank in order to accommodate the corrugations in the cylindrical tank. Such corrugations, in conjunction with the housing wall of the heater, constituted the external flues. Not only is the fabrication of such an end plate expensive, but adequate sealing of the plate to the tank introduces complicating problems.

In accordance with the instant invention, fluting of the end plate is obviated by the employment of either one of two alternative constructions. In the first type of construction, the water tank is of conventional cylindrical form and is not deformed, embossed or recessed in any way. The channeling required to create the outside fines is effected, instead, in the housing of the heater circumjacent the water tank, generally by outwardly deforming or corrugating the inner wall of the housing. In the second type of construction, the tank itself is deformed by being either embossed or recessed, but the deformed portions do not extend the full height of the tank. That is to say, they stop short of the top and bottom edges of the tank, so that a conventional end plate, generally circular, may be employed, thereby obviating the attendant construction and welding difiiculties inherent in prior art devices.

By the instant constructionobviating the fluted end plate which constitutes the weak point of prior art water tanks-a hotter burner may be used beneath the water tank. Such a burner, however, causes undue heating of the walls of the burner chamber. This problem is met in the instant invention by a unique design of inlet passages through which combustion air is fed in such a manner that the air serves as a constantly changing insulation or buffer between the hot burner and the chamber wall.

Several species of the instant invention will now be described in connection with the accompanying drawings wherein:

Figures 1, 2 and 3 are views of a preferred species of the instant invention, Figure 1 being a sectional elevation of the heater; Figure 2, a cross-sectional view taken on line 22 of Figure 1; and Figure 3, an enlargement of a portion of the Figure 2 section.

Figures 4 and 5 illustrate the second species of the instant invention, Figure 4 being a sectional elevation and Figure 5, a cross-section taken on line 55 of Figure 4.

Figures 6 and 7 illustrate a third species of the invention, Figure 6 being a sectional elevation, and Figure 7 being a cross-section taken on line 77 of Figure 6. The embodiment illustrated in Figure 6 bears a marked similarity to that of Figure 4 and may therefore be regarded as a sub-species of the Figure 4 embodiment.

Figures 8 and 9 illustrate a fourth species of the invention, Figure 8 being a sectional elevation and Figure 9, a cross-section taken on line 99 of Figure 8.

Figures 10 and 11 illustrate a fifth species of the invention, Figure 10 being a sectional elevation and Figure 11, a cross-section taken on line 1111 of Figure 10. The Figure 10 embodiment bears a marked resemblance to that of Figure 8 and may therefore be properly regarded as a sub-species of the Figure 8 embodiment.

In the preferred embodiment of the invention illustrated in Figures 1, 2 and 3, the numeral 16 designates a generally cylindrical water tank composed of two identical halves 17 and 18 fitted together With a vertical seam 19. While this method of construction is preferred for this species, it will be readily appreciated that the essence of the tank 16 is a substantially cylindrical vertical wall portion 21 closed at top and bottom by the respective end wall portions 22 and 23.

In the first embodiment here under description, the tank 16 may be substantially any cylindrical type water storage tank. It is preferred, however, to use a tank of the type disclosed in the copending application of Llewellyn Evans, Serial No. 180,571, filed August 21, 1950, now abandoned, wherein the tank 16 is of steel and contains a copper tank 20 immediately therewithin which c0nstitutes a liner therefor.

Tank 16 is supported by and contained within a double-walled housing 24, consisting essentially of an upright cylindrical inner wall 26 and a similar outer wall 27, the interspace between the two walls containing insulation 28. As best seen in Figure 3, the tank 16 is secured as by welding to the circumferentially contiguous inner wall 26 of the housing 24.

The outside flue construction is effected in the instant species by outwardly deforming the inner wall 26 of the housing 24 to form a plurality of elongated recesses 31 spaced around and facing the cylindrical wall of the tank 16. These recesses extend at top and bottom beyond the corresponding ends of the cylindrical portion 21 of the tank 16, thereby constituting, in conjunction with the cylindrical portion 21, flue means for the passage of hot gases from the burner chamber 32 upwardly past the tank 16 and into an upper chamber 33, formed by the end wall portion 22 and a cover plate 34 constituting the top of the heater. An axial chimney stub 36 is provided in the cover plate 34 for the venting of the hot gases. The upper edges of the housing walls 26 and 27 are secured to the cover plate 34. It is preferred to stop the recesses 31 short of the top and bottom edges of the wall 26. This feature, at the bottom, serves to smoothly deflect the gases up the flues, and at the top, to deflect the gases inwardly toward the chimney 36, thereby minimizing hot spots around the edge of the cover plate 34.

A water inlet pipe 37 and a Water outlet pipe 38 are provided, passing through the housing and tank wall into the interior of the tank 16. A temperature sensitive element 39 is inserted into the tank to permit temperature control of the water.

The improved construction described immediately above, in which the tank 16 is permitted to retain its strong and rugged cylindrical configuration While still obtaining the advantages of outside flue heating, makes possible the employment of a burner 41 of higher heat emission properties than could otherwise be used. Such a burner, however, brings with it the problem of abnormal heating of the interior 42 of the chamber walls immediately adjacent the periphery of the burner. To allevlate excessive heating of the wall interior 42, the instant invention contemplates that combustion air for the burner 41 shall be admitted in such fashion as to continuously wipe the surface 42 with a blanket of cool incoming air, thereby cooling the said surface from the intense heat of the burner 41 and the immediately adjacent portion of the burner housing. To this end a horizontal annular partition 43, spanning the interspace between the inner wall 26 and the outer wall 27 of the housing 24, is secured near the bottom of the housing so as to provide an air inlet chamber 44 therebeneath and support the insulation 28 thereabove. Air is admitted to the annular chamber 44 through a plurality of inlet passages 46 provided in the bottom plate 47, which closes the bottom portion of the heater and secures the walls 26 and 27 of the housing 24 in place.

Near the bottom of the inner wall 26, which constitutes the vertical housing for the burner chamber 32, and below the partition 43, the wall 26 is perforated to provide a plurality of air inlets 48. Within the chamber 32 and secured to the interior surface 42 is an annular horizontal baffle 49 circumjacent the burner 41 and approximately level with the upper surface thereof. Combustion air is drawn in continuously through the passageways 46, into the annular interspace 44, through the inlets 48, and through the annular gap between the inner edge of the baffle 49 and the periphery of the burner 41 into the chamber 32. This relatively cool air thus serves to continuously wipe the hot surfaces in the interior of the burner housing and thus provides a blanketing layer of cool air against the heat of the burner 41.

Turning now to the species illustrated in Figure 4, the water tank is shown comprised of a vertical cylinder 51, closed at top and bottom by end plates 52 and 53, respectively, which are welded to the cylinder 51 in conventional manner to constitute a water-tight tank. The wall of cylinder 51 is deformed outwardly to form a plurality of elongate, generally vertical bosses 54, spaced around the cylinder 51. These bosses may be slightly inclined, as illustrated, if desired. It is to be noted that the bosses 54 do not extend the full length of the cylinder 51, but stop short of the edges thereof so that securing of the end plates 52 and 53 is unaffected by the embossing. That is to say, if the cylinder 51 is circular, as is generally the case, the end plates 52 and 53 may constitute simple circular caps, there being no necessity for altering this construction to accommodate the bosses 54.

As with the first species, the Figure 4 embodiment includes a double-walled housing 56, the inner wall 57 of which is immediately circumjacent the embossed portion of the cylinder 51, thereby supporting the Water tank and forming, in conjunction with the bosses 54, flue means 58 for the upward passage of hot gases from the burner to the chimney. in the Figure 4 embodiment the inner cylindrical wall 57 may be formed with undisturbed cylindrical contour, since the bosses 54 of the tank provide the necessary flue means 58.

The embodiment shown in Figures 6 and 7 is similar to that shown in Figures 4 and 5, except for the readily evident difference in the shape of the lands 54. This difference is best seen by comparison of Figures and 7. The construction of this embodiment results in generally semi-cylindrical flue passages 58 formed between the cylinder 51' and the inner wall 57 of the housing 56'.

The species illustrated in Figures 8 and 9 is characterized by the fact that the cylindrical portion 61 of the water tank is deformed inwardly to form the elongate, generally vertical channels 62 spaced around the tank. Like the Figure 4 species, that of Figure 8 is closed by top and bottom end plates 63 and 64 to form the water tank. Since the channels 62 stop short of the top and bottom edges of the cylinder 61, the end plates 63 and 64, like their counterparts 52 and 53, raged not be specially fluted to accommodate the bosses It is necessary in this species, however, to form an annular recess 66 in the inner wall 67 of the housing 68 at the level of the top edge 69 of the cylinder 61, and an annular recess 71 at the level of the bottom edge 72 of the cylinder 61, to create a gas passage past the respective edges of the cylinder, which would otherwise block the flue passages formed by the channels 62. It will be noted, however, that this deforming or channeling does not disturb the unbroken cylindrical contour of the outer housing wall 73; the only effect to the housing being merely a narrowing of the thickness of the insulating interspace 74 immediately circurnjacent the recesses 66 and 71. As in the other embodimfints, the interspace 74 is filled with insulation 76.

The modification illustrated in-Figures l0 and 11 is similar to that of Figures 8 and 9 except that the inwardly deformed portions 81 are somewhat serpentine in character, thereby providing greater passage distance for the flue gases and causing them to remain in contafct with the tank wall 82 for a somewhat longer period 0 time.

From the foregoing description it will be readily appreciated that the instant improvement in water heaters of the external flue type greatly simplifies the construction of the water tank and renders it much easier to obtain well sealed end plates at top and bottom of the tank. If desired, the type of rounded-end cylinder illustrated in Figure 1 may be employed. Either type obviates the requirement for specially fluted end plates with the attendant disadvantages and weakness of weld to the cylindrical tank wall.

It will be further appreciated that the enlarged burner made possible by this simplification in water tank construction may be now readily accommodated through the use of the special air inlet means which serves to wipe the hot portion of the burner chamber walls with a stratum of cool incoming air.

While we have herein shown and described our invention in what we have conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of our invention, which is not to be limited to the details disclosed herein, but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices.

Having described our invention, what We claim as new and desire to secure by Letters Patent is:

1. A water heater comprising in combination a substantially cylindrical water tank closed at top and bottom by substantially hemispherical walls, a housing enclosing said tank and having a generally cylindrical inner wall circumferentially contiguous to said tank, said inner wall of said housing being deformed outwardly to form a channel for the passage of flue gases extending upwardly the full height of said tank, said housing having an open space above said tank communicating with said channel, said housing including a cover plate having a flue opening in the center thereof for evacuation of flue gases, and a burner centrally located in the bottom portion of said housing directly beneath said tank, gases from said burner rising directly upward to the hemispherical bottom of said tank and being deflected smoothly outward into said channel, thence rising in said channel to said space and out said flue opening.

2. A water heater comprising in combination a substantially cylindrical water tank closed at top and bottom by substantially hemispherical walls, a substantially cylindrical housing enclosing said tank and having a generally cylindrical inner wall circumferentially contiguous to said tank, said inner wall of said housing being deformed outwardly to form a channel for the passage of flue gases extending upwardly the full height of said tank, the area of said inner wall in contact with said tank being appreciably greater than the area of said inner wall which is deformed outwardly to form said channel, whereby the heat transferring wiping action of flue gases in the channel is limited by the wiping area available on the tank, said housing having an open space above said tank communicating with said channel, said housing including a cover plate having a flue opening in the center thereof for evacuation of flue gases, and a burner centrally located in the bottom portion of said housing directly beneath said tank, gases from said burner rising directly upward to the hemispherical bottom of said tank and being deflected smoothly outward into said channel, thence rising in said channel to said space and out said flue opening.

References Cited in the file of this patent UNITED STATES PATENTS 62,308 Barden Feb. 26, 1867 1,583,680 Fowles May 4, 1926 1,691,334 Braden Nov. 13, 1928 1,752,536 Mitchell Apr. 1, 1930 1,776,984 Sinton et al. Sept. 30, 1930 (Other references on following page) Schnepp Apr. 28, 1931 Lum July 30, 1935 Strong Oct. 13, 1936 5 Breese Jan. 22, 1946 Breese Mar. 19, 1946 6 Miller July 30, 1946 Kittrell Nov. 9, 1948 Jensen Dec. 28, 1948 Mustee Dec. 20, 1949 Anderson et a1 Jan. 16, 1951

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