US3236226A - Combined air and water heaters - Google Patents

Description

Feb. 22, 1966 J. H. EUBANKS COMBINED AIR AND WATER HEATERS 4 Sheets-Sheet 1 Filed May 28, 1963 INVENTOR Joseph H. Eubanks ATTORNEYJ Feb; 22, 1966 J, EUBANKS 3,236,226

COMBINED AIR AND WATER HEATERS Filed May 28, 1963 4 Sheets-Sheet 2 INVENTOR Joseph H. E ubanks ATTORNEYS J. H. EUBANKS 3,236,226

COMBINED AIR AND WATER HEATERS 4 Sheets-Sheet 5 Feb. 22, 1966 Filed May 28, 1963 INVENTOR Joseph H. Eubanks BY M? y% ATTORNEYS Feb. 22, 1966 J. H. EUBANKS COMBINED AIR AND WATER HEATERS 4 Sheets-Sheet 4 Filed May 28, 1963 INVENTOR Joseph h. Eubanks M%6w4 ATTORNEYS United States Patent 3,236,226 COMBINED AIR AND WATER HEATERS Joseph H. Eubanlrs, Schuylkill Haven, Pa., assignor to Thermodynamics, Schuylkill Haven, Pa., a corporation of Pennsylvania Filed May 28, 1963, Ser. No. 283,762 3 Claims. (Cl. 126101) This invention relates to heating systems and more particularly to combined heating systems for supplying from a single source the warm air or water required for space heating and the hot water required for the usual domestic purposes.

While the advantages of combining a furnace and a domestic hot water heater have long been recognized, separate units continue to dominate the market because of the failure of prior proposals to provide an efficient, compact, flexible and inexpensive combined unit.

In many cases the cost of the combined unit has exceeded the total cost of the conventional separate units. Also, in most cases the combined units were not able to supply efficiently the widely varying requirements for warm air and hot water and to accommodate the change in requirements between summer and winter operation.

It is, accordingly, a principal purpose and object of the present invention to provide improved combined air and water heaters which overcome these deficiencies of prior units and which olfer increased efficiency and flexibility of operation and yet which are compact and of simplified, durable construction and which can be manufacture d, sold and operated at reduced cost.

It is a further object of the present invention to provide improved combined air and water heaters which because of their unique construction eliminate extreme temperature diiferentials throughout the system thus increasing their service life and increasing their efliciency.

It is also an object of the present invention to provide improved combined air and water heating units which are unusually compact and may thus be installed in a variety of locations within a dwelling.

It is a further object of the present invention'to provide improved combined air and water heaters which have an unusual degree of flexibility of operation and which accordingly can be utilized to satisfy all of the requirements for heating systems having widely differing configurations. For example, the novel units herein disclosed may be used in a system in which a portion of the dwelling is heated by forced hot air and the remainder is heated by hot water supplied to conventional radiators or to baseboard heaters or the like.

Additional objects and advantages will become apparent as the description proceeds in connection with the accompanying drawings in which:

FIGURE 1 is a side view of the combined air and water heater unit of the present invention with parts broken away to show interior details;

FIGURE 2 is a top plan view of the unit;

v FIGURE 3 is a front view of the unit of FIGURE 1;

FIGURE 4 is a rear view with parts broken away to show interior details; and

FIGURE 5 is an enlarged fragmentary section of one of the combined heat exchanger assemblies employed in the unit.

Referring now more particularly to the drawings, the main heat exchange portion of the combined air-water heater of the present invention is enclosed in a housing 20 of sheet metal construction formed by a bottom wall 21, and side walls 23 and 24 welded or otherwise suitably secured together.

The ends of the housing 20 are formed by a pair of headers, 25 and 26 which extend over the full width and ice height of the housing and are welded to the bottom wall 21. The header 25 comprises inner and outer walls 27 and 28, top wall 29 and side walls 30 and 31 which form extensions of the housing side walls 23 and 24, the walls preferably being welded to form a water tight structure. The header 26 is of similar construction and includes inner and outer walls 32 and 33, a top wall 34 and side walls 35 and 36.

Secured to the lower port-ion of end wall 33 of the header 26 is a combustion unit 37 which, in the present. instance is an oil burner. A flue collector 38 leading to a smoke pipe 39 is also mounted on the wall 33 above the oil burner 37. The side wall 24 of the housing has a lower shrouded opening 40 for connection to the outlet scroll of a fan 42 driven by -a motor 43, the fan and motor being mounted in a housing 44 extending vertically in side-by-side relation with the housing 20. The upper end of the fan housing is connected to the conventional return air ducts (not shown) through an opening 46. The usual replaceable filter 48 is positioned in the housing 44 in the path of the incoming air. The top of the main housing 20 is provided with a central open-ing 50 for connection to the warm air delivery ducts (not shown) which lead to the several rooms of the dwelling. The air delivered by the fan 42 passes through the opening 40 and around a combustion tube 52 then upwardly across the heat exchange apparatus to be described, through a rectangular passage formed by the side walls 23 and 24 and inner walls of the headers 25 and 26.

The combustion tube 52, which is cylindrical, is welded at one end to the header wall 32 in surrounding relation with an intermediate tube 55 which extends through header 26 and connects the burner 37 to the interior of the combustion tube 52 and is welded to the header walls 32 and 33. The opposite end of the combustion tube 52 extends through header 25 and is welded to the header walls 27 and 28.

The combustion tube 52 opens into a collector chamber or gas reversal chamber 58 formed by a rectangular sheet metal structure 59 welded to the outer header wall 28. The gas reversal chamber is closed by a cover 60 detachably secured by clamps 62 to the sheet metal annulus 59. The cover 60 is preferably lined or filled with an insulating refractory material.

The principal heat exchange area within the heater of the present invention is provided by a series of identical fire tube, water tube assemblies, each of which is indicated generally at 64. As best shown in FIGURE 5, each of these assemblies comprises an inner fire tube 66, the opposite ends of which are supported by and welded to the header walls 28 and 33, respectively. Thus, these fire tubes 66 connect the gas reversal chamber 58 with the collector 38 to provide a path for the hot combustion products produced by the burner 37. The fire tubes 66 are surrounded by water tubes 68, the opposite ends of which are supported by and welded to the inner header walls 27 and 32. Thus, the annular spaces between the water tubes 68 and the fire tubes 66 provide a series of paths for connecting the two water filled headers 25 and 26. It will be noted that the heat exchanger assemblies 64 are each inclined slightly to promote convection flow from right to left as viewed in FIGURE 1. The headers 25 and 26 are also connected by lower and upper conduits 69 and 71.

To increase the heat exchange capacity of the units 64, they are provided with a series of thin sheet metal rectangular fins 70 which are press fitted onto the outer periphery of the water tubes 68. The fins are of rectangular configuration and are so dimensioned that they occupy substantially the entire air passage above the combustion tube 52.

The supply of domestic hot water is obtained by an immersion coil 72 which extends substantially entirely across the header 26. The immersion coil is provided with the usual inlet and outlet connections 74 and 76, respectively, for connection to the hot water lines of the dwelling. While the immersion heater is shown positioned at the upper end of the header 26, it may also be mounted between the tube 55 and the lowermost of the heat exchanger assemblies 64 or may be mounted below the tube 55, depending on the requirements of the particular installation involved.

To assure maximum efficiency of operation and to provide sufiicient hot water or suificient hot air without excessive heating of the air or of the water, separate controls are provided for the burner 37 and the fan 42. More specifically, the burner 37 is controlled solely in response to the temperature of the water, preferably sensed by an aquastat which is positioned in the header 26 adjacent the immersion coil 72. The operation of the fan 42, on the other hand, is controlled by a room thermostat positioned in the usual location in the dwelling. Accordingly, the volume of water filling both the headers and the heat exchange unit 64 is constantly maintained at or very close to a predetermined temperature which is sufiicient to satisfy the demand for hot water or for hot air up to the rated capacity of the unit. When the room thermostat calls for additional heat the fan 42 is put into operation to cause the air to circulate over the fins 70, the water tubes 68, and the inner surfaces of the headers 25 and 26. The total area of these heat exchange surfaces is more than adequate to heat the air thus circulated to the required temperature. The temperature of the water required to produce the desired air temperature is entirely compatible with the temperature required to satisfy the needs for domestic hot water.

The temperature of the heated reservoir of the water will be reduced whenever the fan 42 operates or when domestic water is used. Under these circumstances the burner will operate to restore the heat level of the water in the two headers.

Because of the substantially constant temperature of the components, the deterioration which occurs in the usual warm air furnace in summer is entirely eliminated. Also extreme temperature differentials, which are unavoidably encountered in the usual warm air furnace, are eliminated because of the water backing of the surfaces which are exposed to the highest temperatures.

The entire unit is unusually compact. For example, a unit having a 100,000 B.t.u. capacity, which is suflicient for the normal three bedroom house, is only 30 inches high and about 40 inches long. Within this relatively small envelope the capacity can be varied as desired by adding or deleting one or more of the heat exchange assemblies 64.

Because of the relatively large reservoir of heated water, this water can be used for space heating as well as for heating water for domestic requirements. For example, in one level houses of the ranch type, the runs of the warm air ducts are so long that it is difiicult to insure an adequate supply of warm air to rooms which are remote from the heating unit. In such a case these difficult to heat rooms can be served by a hot water system, for example, radiant baseboard heating or a full radiant system. Thus the unit can be tailored exactly to meet unusual as well as conventional requirements with little or no added cost.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

l. A combined air and Water heater comprising a housing having essentially vertical side walls and end walls and an essentially horizontal top Wall, means forming Water filled headers extending the full Width and height of said end walls inwardly thereof, the inner walls of said headers and said side walls forming an air passage connecting an opening in one of said side walls and an opening in said top wall, a burner carried by one of said end walls for supplying heated combustion products, means forming a gas reversal chamber adjacent the opposite end wall, a combustion tube assembly extending through each of said headers and across said air passage connecting said burner and said gas reversal chamber, a fan for forcing air through said passage and over a portion of said combustion tube assembly, a plurality of heat exchangers extending across said air passage between said headers, said heat exchangers each having a water tube connecting the interior of one header to the interior of the other header, and each heat exchanger having a fire tube extending through said headers through which the combustion products pass from said gas reversal chamber to a smoke pipe.

2. A combined air and water heater comprising a housing having essentially vertical side walls and end walls and an essentially horizontal top wall, means forming water filled headers extending the full width and height of said end walls inwardly thereof, the inner walls of said headers and said side walls forming an air passage connecting an opening in one of said side Walls and an opening in said top wall, a burner carried by one of said end walls for supplying heated combustion products, means forming a gas reversal chamber adjacent the opposite end wall, a combustion tube assembly extending through said headers and across said air passage connecting said burner and said gas reversal chamber, a fan for forcing air through said passage and over a portion of said combustion tube assembly, a plurality of heat exchangers extending across said air passage between said headers, said heat exchangers having a water tube connecting the interior of one header to the interior of the other header and each heat exchanger having a fire tube extending through said Water tube concentrically thereof and extending through said headers into said gas reversal chamber, the combustion products passing through said fire tube from said gas reversal chamber to a smoke pipe, and a plurality of fins carried by the outer surface of each of the said water tubes and substantially filling said air passage.

3. A combined air and water heater comprising a hous ing having side walls, water filled headers extending the full width and height of said housing and forming the ends thereof, the inner walls of said headers and said side Walls forming an air passage, means forming a gas reversal chamber at the outer side of one of said heaters, a plurality of heat exchangers extending across said air passage between said headers, said heat exchangers each having a water tube connecting the interior of one header to the interior of the other header, and each heat exchanger having a fire tube positioned within and extending through said Water tube and through said headers, one end of said fire tubes communicating with said gas reversal chamber and the other end of said fire tubes communicating with a smoke pipe, a burner for supplying heated combustion products, a combustion tube assembly extending through each of said headers and into said gas reversal chamber and connecting said burner to said gas reversal chamber, a plurality of heat exchanger fins carried by said water tubes externally thereof, a fan for forcing air through said air passage over a portion of said combustion tube assembly and over said heat exchanger fins and said water tubes.

(References 011 following page) 5 6 References Cited by the Examiner 2,216,175 10/ 1940 Helbing.

2,533,508 12/1950 Riu 126101 UNITED STATES PATENTS 2,573,364 10/1951 Scharif 1261()1 1,532,506 4/1925 McGregor 23718 2,786,634 3 1957 w n 12 10 X 1,607,458 11/1926 Hocher 126101 2,006,849 7/ 1935 Warren 5 JAMES W. WESTHAVER, Primary Examiner.

2,026,031 12/1935 Gerspacher 126-101

Claims (1)

1. A COMBINED AIR AND WATER HEATER COMPRISING A HOUSING HAVING ESSENTIALLY VERTICAL SIDE WALLS AND END WALLS AND AN ESSENTIALLY HORIZONTAL TOP WALL, MEANS FORMING WATER FILLED HEADERS EXTENDING THE FULL WIDTH AND HEIGHT OF SAID END WALLS INWARDLY THEREOF, THE INNER WALLS OF SAID HEADERS AND SAID SIDE WALLS FORMING AN AIR PASSAGE CONNECTING AN OPENING IN ONE OF SAID SIDE WALLS AND AN OPENING IN SAID TOP WALL, A BURNER CARRIED BY ONE OF SAID END WALLS FOR SUPPLYING HEATED COMBUSTION PRODUCTS, MEANS FORMING A GAS REVERSAL CHAMBER ADJACENT THE OPPOSITE END WALL, A COMBUSTION TUBE ASSEMBLY EXTENDING THROUGH EACH OF SAID HEADERS AND ACROSS SAID AIR PASSAGE CONNECTING SAID BURNER AND SAID GAS REVERSAL CHAMBER, A FAN FOR FORCING AIR THROUGH SAID PASSAGE AND OVER A PORTION OF SAID COMBUSTION TUBE ASSEMBLY, A PLURALITY OF HEAT EXCHANGERS EXTENDING ACROSS SAID AIR PASSAGE BETWEEN SAID HEADERS, SAID HEAT EXCHANGERS EACH HAVING A WATER TUBE CONNECTING THE INTERIOR OF ONE HEADER TO THE INTERIOR OF

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