US2205451A - Furnace construction - Google Patents

Description

June 25, 1940. I WQQLER'Y 2,205,451

FURNACE CONSTRUCTION Filed May 31, 1938 2 Sheets-Sheet 2 Patented June 25,1940.

' 3 UNITED STATES PATENT OFFICE a 1 i t 2,205,451

- summon coNsraUc'rroN Horace E. Woolcry, St. Paul, Minn.

Application May 31, 1938, Serial No. 210,903

3 Claims.

This invention relates generally to improvements in heating devices or furnaces, and more particularly to improvements in central heating units of the oil burning type and in which air from the heated enclosure is forcibly circulated through the heating unit and recirculated in the enclosure.

Units of this type, with which I am now familiar, generally employ a fan for circulating and recirculating the air and employ a separate fan for supplying the air needed for the oil burner. This assembly entails a needless duplication of parts, in thattwo separate fans, and operating motors therefor; are used, and in addition, since the air for the burner is generally taken from the room or space'in which the unit is located, there results a.depletion ;of. pure air therein. In respect to the latter fault of the previous installations, it hasbeen noted that the use of the airfrom: the=basement wherein the unit is ordinarily located has often necessitated an unreasonable amount of ventilation therein in order to supply adequate fresh air for the burner. Since the basement is ordinarily used but very little, this admission of outdoor air, in excess of the normal requirementsior ventilation, represents added heating load and a loss in. heating efiiciency of the plant as a whole. My invention, therefore, has as its "primary object the provision of a heating unit or plant in which the air required for the burner is taken entirely from within the heated enclosure instead of from some external source, such as the basement; Inasmuch as adequate ventilation of the heated enclosure must be provided in any event, for the sake of the health of the occupants thereof, this air taken from theenclosure for the burner represents no added'load to the heater.

Another andequally important object of my invention is to provide a heating unit wherein the air for the burner is not only taken from the heated enclosure, but is also circulated and carried to the burner by the same fan which circulates the air through the heating unit as a whole. In this manner, then, a single fan and motor are caused to perform two distinct functions, that of circulating the air and feeding air to the burner, and one complete fan' and motor assembly is eliminated from the cost and upkeep of the heating unit.

Another object is to provide a heating unit or assembly of-this kind wherein the circulated air taken from the heated enclosure, after a small fraction thereof has been diverted to the burner, is blowni-through a heating or radiator-element line 33 in Fig. 1.

to be heated thereby, and is then recirculated through the room. The said heating element is designed to provide amaximum of heating surface in a relatively small space, and is so designed that all of said surface is exposed to the heat 5 and to the air currents circulated by the fan or blower to thus obtain the maximum possible efficiency in the heat transfer to the air.

Another object is to provide, in a heating plant of the kind described, a novel and extremely ef- 10 fective and simple assembly of air circulating fan, motor, and oil pump, all arranged in compact form and in such manner that a single motor operates both the fan and pump for supplying air and oil to the burner and for cir- 15 culating the air from the heated enclosure I through the plant.

A further object is to provide an assembly of this kind wherein the air for the burner is tapped or taken from the main air stream circulated'by the fan, and is carried to the burner through a passageway or duct of relatively small cross sectional area so that the air enters the burner at relatively highvelocity. This feature has been found to completely eliminate-what is generally termed flutter of the burner flame, and which is actually a pulsating action of the flame due to lack of air and proper combustion. To further regulate the velocity of the air a Venturi tube may be arranged to feed the air from the circulating fan to the burner.

Still a further object is to provide a heating unit or assembly having the foregoing desirable features, but which is extremely compact in size and inexpensive in both initial cost and upkeep.

The foregoing and other objects, together with means whereby the same may be carried into effect will best be understood from the following detailed specification, reference being had therein to the accompanying drawings, in which:

Fig. l is a vertical and longitudinal sectional view through a heating unit or plant constructed in accordance with my invention.

Fig. 2 is a. fragmentary cross section, along the 45 line 2-2 in Fig. 1, showing only the upper portion of the fire box and lower portion of the heating element.

Fig. 3 is a horizontal cross section along the Fig. 4 is a fragmentary cross section through the upper portion of the unit, taken along the line 44 in Fig. 1.

Referring now with more particularity to the drawings, the essential elements of my invention ll are shown as assembled within a suitable housing A to form what is known as a central, or unit, heater designed to be located in the basement or other out of the way room of the building and having air inlet and outlet openings B and C which are connected by suitable ducts, piping or fioor grills with the enclosure to be heated. These openings B and d are, accordingly, formed in the top of the housing A, and a central partition D in the housing is located between these openings to divide the housing into two large separate chambers'E and F, hereinafter known as the fan and heating chambers, respectively.

A fire box 5 is located in the lower portion of the chamber F and comprises the metal pot 6 lined with fire brick I and having a cover plate 8. An oil burner 9 of any conventional type is located in the air and draft tube assembly I8 and which in turn is inserted into the fire box 5 through openings II in the partition D and the fire brick lining I so that the fiame end of the burner enters the fire box while the inlet end projects into the lower portion of chamber E.

The heating or radiator element, designated generally at 12, is made up primarily of a long sheet of metal which is reversely folded back upon itself a great number of times to provide a plurality of oppositely opening fiat channels or fiues separated by intervening folds in the metal sheet. The radiator thus formed is set on end on the cover plate 8 of the fire box 5, and a back plate 13 is welded to the vertical back side of the assembly to close all of the channels thereat, except as will presently appear. The cover plate 8 has an opening l4 coextensive with the bottom area of the radiator l2, and over which the radiator is mounted and secured by welding around its lower edge. or flues formed by this folding of the sheet metal for the radiator l2 are designated at [5 and I5 and are respectively termed the fire and air channels, as indicated by their respective uses. These channels are vertically extended, and the air channels I5 open at their upper ends and at the side opposite the back plate 13, while the fire channels l5 are closed all around except over the opening l4 in the fire box cover plate 8. The intervening folds I'I defining these channels l5 and IE, or course, isolate each air channel from the adjacent fire channels. The folds or walls I! at their lower ends are spread or flared apart angularly at the lower end of each fire channel l5, and meet at their extremities where they are welded together at l8vto isolate and completely close off the lower end of each air channel l5. Also secured between these walls I! and in the lower ends of the air channels ii are the heat radiating fins or bars l9 welded in place at the junction lines l8 and being coextensive therewith. The backplate i3 has openings 28 which communicate with the angular lower end portions of the channels l6 and extend upwardly to about the level of the upper edges of the fins A smoke pipe 2| extends transversely across the upper end of the radiator l2, and is welded thereto at 22. The upper ends of the fire chan-- nels l5 are closed at each side of this pipe 2|, as designated at 23, but communicate with the pipe through openings 24. On' the other hand, the air channels l5 are open at each side of the pipe 2| but are closed adjacent the pipe by walls 25 and the arrangement, therefore, is such that fumes or smoke traveling upwardly through the fire channels l5 may enter the smoke pipe while The channels air moving upwardly through the air channels 15 may flow past, but cannot enter, the pipe. One end of the pipe extends outwardly through the housing A for connection to the chimney (not shown), while the other end may be closed as at 28 in order to positively seal the chamber F from any gases or smoke which may arise from the burner 9.

A circulating fan or blower assembly, designated generally at 21, is provided in the chamber E, and comprises a housing 28 which is secured at 29 to the partition D so that the outlet opening 30 of the housing communicates with the chamber F through an opening 3| cut in the partition just above the level of the fire box 5. The fan rotor 32 is journaled in the housing 28 by an axle 33, and this fan preferably, though not necessarily, is of the type embodying a great number of transversely arcuated, angularly set blades or paddles 34 which are spaced around the end rims 35. Air from the chamber E enters the housing 28 through openings 35 in each end thereof, and flows into the fan rotor 32 which. when rotated rapidly in the direction indicated by the arrow, discharges the air at high velocity through the opening 3| and into the chamber F. This air, in discharging as described, flows along the lower wall 31 of the housing, as designated by the arrows.

The fan rotor axle 33 is journaled in bearings 38, and at one end carries a pulley 39 over which is trained a drive belt 40. This belt also engages the pulley 4| of an electric motor 42 which is mounted atop the fan housing 28 to drive the fan. This motor also serves, in accordance with one of the objects of my invention, to drive the fuel pump 43 to which it is connected and assembled as a unit, and this pump forces the oil or fuel to the burner 9 through the pipe 44.

In further carrying out my invention, and as one of the most important objects thereof, I provide means at 45 by which a small part or quantity of the air moved by the fan 32 is tapped off from the main air stream and caused to enter the burner housing ID. This tap line or duct 45 comprises a tubular member of any suitable kind which extends from an opening 46 formed in the lower wall 31 of the fan housing 28 near the outlet of the fan and to another opening 41 formed in the burner housing or tube I0. As here shown, and for the purposes of facilitating installation of the parts, the member 45 comprises tubular couplings or collars 48 which are secured by flanges 49 (or by welding) around the openings 45 and 41, and which are joined by a coupling sleeve or tube 50 telescopically assembled. A butterfly valve 5|, or equivalent means, may be located in the member 45 to control the amount of air flowing therethrough.

In operation, the burner 9 heats the interior of the fire box 5, and this heat flows up through the fire channels l5 to heat the walls ll of the radiator-to a very high temperature. At the same time, the fan rotor 32 draws in air through the openings 35 and discharges this air into the chamber F where it enters the open frontal sides of 'the air channels l5 and flows upwardly therein in contact with the heated walls H. The air is thus heated and-rises through the opening C to the heated enclosure, and, after being circulated therein, it is drawn back through the opening B by action of the fan 32. There results, then, a continuous circulation and recirculation of the air, during the course of which it is heated by contact with the heated walls of the radiator assembly l2. It will be readily evident that, due to the great number of, and great area of, these walls ll, the heat transfer will be rapid and efficient, and a high heating efiiciency will be obtained. This is true even though the unit is relatively compact due to the novel manner of fabricating the radiator from a length of folded sheet metal so that, while it retains its effective area, it nevertheless occupies but a very nominal space in the unit.

As the air enters the chamber F it will be noted that it flows, at least in part, directly along the bottom of the air channels l6 where it comes in contact with the parts where heated to their greatest temperature, and a part of the air further flows through the, openings 20 to thus travel upwardly along the back plate l3 and contact all surfaces of the radiator element. The lower flared ends of the fire channels iii are, of course, the hottest points in the entire radiator assembly, and it is important that the air contact these parts, as stated. This is accomplished by so locating the fan rotor 32 and air outlet 30 that their lower margins lie substantially in the same horizontal plane as these parts. To prevent overheating of the welded junctions l8 of the walls I], the fins I9 are provided in order to present a greater heat radiating surface to the air. These fins may have apertures as denoted at 52, to facilitate the air circulation. I A small part of the air stream flowing from the fan rotor 32 along the bottom wall 31 of the housing is diverted through the tubular tap member 45 to the burner tube ID, to supply the air required for proper combustion.- Inasmuch as this burner air represents but a small part of the air circulated by the fan, this tapping of the burner air from the main source entails no added ventilating difliculties and permits a single fan and motor to carry out the functions heretofore assigned to two such assemblies. There results, therefore, a considerable simplification in assembly and reduction in cost. Furthermore, it has been found that, due evidently to the high velocity of the air entering the burner through the tubular member 45 of relatively small diameter, the frequently encountered fluttering action of the flame of the oil burner is completely eliminated.

In this connection it will be noted that a Venturi tube or Venturi-shaped member 53 may be used in the tubular tap member feeding the burner to further regulate the velocity of the air entering the burner, and this represents an important feature of the invention. In furtherance of the same action, the particular type of fan rotor as disclosed herein has the characteristic of expelling the air radially at a very high velocity immediately adjacent the outer edges of its blades, and'the air thus enters the tube 45 rapidly.

It is understood that suitable modifications may be made in the structure disclosed, provided that such modifications fall within the'spirit and scope of the appended claims. Having thus fully disclosed my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A heating furnace comprising a heating means, a radiator having vertically extended fire channels and air channels, the said fire channels communicating with the heating means, smoke outlet means at the upper ends of the fire channels, a back plate on. the radiator and having openings at its lower portion communicating withthe air channels, the opposite frontal side of the air channels being open, said channels having outlets at their upper ends, and means for circulating air through the open sides of the air channels and causing a part of said air to move along the lower ends of the channels and through the said openings.

2. A heating furnace comprising a heating unit, a heat exchange structure supported over the heating unit and formed of sheet material to provide a series of vertically extended fiat flues opening toward opposite vertical sides of the structure, aback plate extended across one vertical side of the structure and closing the sides of alternate flues, these flues being open at their lower ends over the heating unit to circulate heat upwardly therefrom and having smoke escape means at their upper ends, the intervening flues being closed at their lower ends and open at their upper ends for escape of the heated air, and means for blowing air through the open sides of the said intervening flues and upwardly through the upper ends thereof at opposite sides of the said smoke escape means.

3. A heating furnace comprising a heating unit, a heat exchange structure supported over the heating unit and having a series of vertically extended flat flues opening toward opposite vertical sides of the structure, means closing the sides of alternate flues, these flues being open at their lower ends over the heating unit to circulate heat upwardly therefrom and having smoke escape means at their upper ends, the intervening fiues being closed at their lower ends but open at one side and at their upper ends, a blower having air discharge means constructed and arranged to blow air inwardly over said lower closed ends of the fiues and then upwardly through their open upper ends.

- HORACE E. WOOLERY.

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