US2396252A - Self-stoking water heater - Google Patents

Description

March 12, 1946. R. c. CROSS SELF-STOKING WATER HEATER Filed May 22, 1944 2 Sheets-Sheet 1 atzbaweg i March 12, 1946. R. c. CROSS SELF-STOKING WATER HEATER Filed May 22, 1944 2 Sheets-Sheet 2 Mere/4 Patented Mar. 12, 1946 SELF STOKING WATER HEATER Robert 0. Cross, Riverside, IIL, assignor to Sears, Roebuck and 00., Chicago',.lll., a corporation of New York Application May 22, 1944; Serial No. 536,707

(or. I22158) 6 Claims.

The present invention relates to domestic hot water heaters and is concerned in particular with solid fuel burning heater construction therefor characterized by a self-stoking fuel supply feature.

In conventional coal burning domestic hot water heaters, fuel is supplied through a side door which leads directly to a combustion chamber, or is deposited downwardly from a top supply door, and the burning of the fuel is performed in the principal fire chamber with the result that liberated products of combustion are wasted. Water jacketing which surrounds the combustion chamber is not always exposed so as to operate as an efficient heat exchange medium because of its location remote from the maximum heat concentrations.

In the present invention there is utilized a downwardly fed fuel suppl construction in which the liberated gaseous combustibles which are freed as a result of the primary combustion process become exposed to a secondary oxygen supply in close proximity to the water jacketed parts of the boiler, so that during their combustion in which maximum heat liberation is achieved, these products are fully consumed as the liberated heat is directed in an enicient manner to the heat exchange water jacketing which forms an outer enclosure of the principal structure.

Accordingly, as its principal object the present invention contemplates the provision of a domestic hot water heater that is magazine fed in its fuel supply and which directs its liberated combustibles resulting from a preliminar burning into a secondary stream of oxygen supply for completion of combustion thereof.

In the attainment of this and other objects the invention is illustrated in a principal embodiment consisting of a cylindrical heater dome that is throughout water jacketed and is p'rovided with a central cylindrical core forminga magazine hopper. This element lies directly'over a rotatable circular grate provided with suitable openings for air admission and ash disposal and provided with conventional oscillating and agitating equipment.

The magazine hopper is preferably lined with refractory material and its lowermost extremity extendsjust beneath a cylindrical fire brick lining in which openings are provided to admit air for secondary oxygen supply; The magazine hopper is sealed by a hinged cover at its upper extremity and except for vent openings forms a closed chamber'for confiningtth'erproductsof combustion that are induced in the? fuel supply directing them downwardly and? outwardly beyond the refractory material lining and into the stream of secondary oxygen supply. An exhaust flue in communication with a circumferential chamber between the hopper and the heater dome draws the gaseous products of combustion as the heat generated thereby is communicated to the heater dome and therethrough to the jacket contained water.

For a more comprehensive understanding of the present invention, reference will now be had to the accompanying drawings and to the following detailed specification, in which like numerical designations identify corresponding parts throughout, and in which:

Fig. 1 is a front elevation of a boiler construction having incorporated therein certain features of the present invention;

Fig. 2 is a plan View of the device illustrated in Fig. 1;

Fig. 3 isa vertical sectional view of the same device taken approximately on line 3--3 of Fig. 2;

Fig. 4 is a plan sectional detail view taken approximately on line 4-4 of Fig. 3 and featuring the construction of the circumferential fire brick wall; and

Fig. 5' is a detailed elevational view of one of the fire brick of which several are used contiguously in forming the circumferential fire wall featured in Fig. 4.

Referring now more particularly'to the draw ings reference character ll designates a base casting which provides an ash chamber l2 accessible from one side through a pivoted ash door 83, Figs. 1 and 3, of customary construction and a draft control door M through which the primary' supply of oxygen is obtained for supporting combustion of the fuel that descends upon the supporting grate IS;

The base casting H is substantially cylindrical in external conformation and affords a turret shoulder as at 1B with a supporting flange l! to receive and confine a water-jacketed dome I 8. An opening is just above the ash clean-out door is admits the secondary oxygen supply into a circumferential distribution chamber 2|, see also Fig. 4, provided between the wall of the base casting l i that extends upwardly from the grate sup porting ledge 22 and a cylindrical fire brick formation consisting of the segmented brick elements 23 that may be cemented together and which are held spaced from the castingwall by reason of their specially provided spacer lugs 24 located at the tops and" bottoms of each brick extremity.

The base casting It rests upon three longitudinally extending feet 25 and, in addition to a floor 26, this element is integrally formed with the aforementioned ledge 22 that terminates with a concentric inner fiange 2? giving support to the ring casting 28 of the grate I 5. The grate is provided with a central opening defined by an inner concentric ring 29 from which there extend the supporting lugs 3|, two on each side of a shaker and draw center 32 that may be of conventional design including a handle 33 to be engaged by a convenience extension member (not shown).

Ledge 22 together with fire grate l divide the space within the base casting H into a fire box or combustion chamber above and an ash chamber l2 below. The primary combustion takes place in the fire box and is supported by the principal source of oxygen admitted through the draft control l4. The products of combustion, together with any partially consumed gases are drawn around the skirt extremity 43 into the space 49 about which more will be said later in connection with secondary combustion thereat.

Each one of t e fire brick 23 is radially fluted as at 34. permitting the admission of the secondary air in numerous small streams to the combustion chamber 49, and the height of the brick coinc des with the distance between the ledge 22 and the s oulder l6 so that the bottom wall of the jacket l8 rests upon said shoulder l6 and is contiguous with the circular ledge formed b the array of brick 23.

The dome I8 is cast with an internal water jacketing chamber 35 coextensive with the entire periphery of t e wall excepting t e flue opening 36 where a thimble 3! is formed for supporting the exhaust pipe 38 through which the products of combustion are drawn off under impetus of the c imney draft a ter the conventional manner. The dome [8 includes a central cover sleeve 39 whose cylindrical inner surface conforms in 44 is preferably beveled at 45 so that fuel may not rest upon the ledge, but instead wi l be directed downwardly into the internal chamber of the hopper.

The sheet metal hopper is also provided with a row of vent openings 46 that communicate between the enclosed chamber of the hopper and a space which surrounds the inner wall 41 of the dome I8 for the purpose of continuousl removing by this direct draft passage, any gaseous products of combustion that may accumulate above the fuel bed. At intervals in a horizontal plane the inner wall 41 of the dome is provided with spacer lugs 48 that help to centralize the hopper by butting against the lowermost extremity of member 4i so as to assure the concentricity of the cylindrical space 49 which may be termed a combustion chamber as will later be explained.

In order to make the apparatus universally adaptab e, the cast dome I8 is provided with two riser bosses 5| and 52 and two return bosses 53 and 54. For efficient operation one of the riser bosses 5i and 52 may be emnoyed with its diagonally opposite return boss 53 or 54 as illustrated in Fig. 1 and the domestic water pipe connections 55 and 56 threaded thereto while pipe plugs 51 may be employed to seal the unused communication bosses according to individual requirements.

The magazine hopper is sealed at its upper end by a sheet metal circular cover 58 which may be engaged by a control handle 59 and pivoted about the pivot stud 6i that extends through the cover hinge bracket 62 and a pair of pivot yokes 63 integral with the dome casting I8, see Figs. 2 and 3. The hinge 52 is cast with a stop lug projection 64 that is designed to rest against the dome as indicated in dotted outline in Fig, 3 when the cover is open.

The cover58. is preferably a sheet metal hollow structure as has been said and is provided in its lower walls with bleeder openings 65 and in its upper wall with additional bleeder openings 65 that may be covered by an adjustable ornamentation button 5'! slightly spaced therefrom so that excessive gas accumulations of combustible material in the chamber of the hopper above the fuel bed may be supplied with an excess of oxygen beyond an explosive mixture thus avoiding the occurrence of local explosive effects in the maga zine.

The operation of the unit which has already been designated in a general sense contemplates a supply of fuel contained within the hopper beneath the cover '58 which is permitted to descend toward the grate 15 as it is consumed and reduced to ash, affording a variable space within the hopper chamber complimentary to the fuel reserve therein contained.

The combustible gaseous products will follow generally the arrows 68 circling the skirt of the refractory liner 43 and coming up into the combustion chamber 49. Meanwhile, combustion supported by an air supply that is admitted through the draft upon the opening of door l4 will burn the fuel that is resting upon the grate E5. The gases, as has been said, will be drawn into the secondary chamber 49 taking on additional oxygen through the radial ports 34 and burning within the chamber 49 in proximit to the inner dome wall 4?. The products of combustion will be drawn through the flue opening 35 into the exhaust pipe 38 and thence out through conventional chimney escapeways, Accumulation of explosive gases above the fuel in the hopper is prevented by the vent openings 46 so that upon the removal of the cover 58 to replenish the fuel reserve, no danger of local explosive effects may be incurred.

While the present invention has been explained and described with reference to a particular embodiment, it is to be understood nevertheless that numerous variations and modifications may be incorporated without departing from the essential spirit or scope thereof. Accordingly it is not intended to be limited by the detailed illustrations in the accompanying drawings, nor by the specific language employed in the foregoing description, except as indicated in the hereunto appended claims.

The invention claimed is:

1. In a fuel burning boiler, a supporting base providing a fire box, a cylindrical refractory wall carried by said base spaced from a concentric cylindrical wall of said base and thus affording an air supply avenue to a combustion chamber, a double walled casting forming a water jacket carried on said base and formed with a vertical collar, a conical hopper supported within said vertical collar defining said combustion chamber between itself and said casting, said hopper being flared downwardly and extending into said fire box, and a pivoted cover for said vertical collar and hopper carried bysaid casting.

2. In a boiler, a double walled dome casting forming a water jacket of cylindrical conformation having a concentric vertical collar, a magazine hopper secured to said collar and extending downwardly into said dome in spaced relation to its cylindrical wall, a flue collar integral with said dome communicating with the space between said hopper and said dome wall for connection with an exhaust pipe, a supporting base for said dome comprising a cylindrical casting having a grate supporting ledge, a grate on said ledge defining an ash compartment and a fire box, a primary air supply opening in said base for supporting combustion on said grate, a cylindrical refractory wall surrounding said fire box having radial vents and spaced from the concentric wall of said supporting base for conducting a secondary air supply to the space between said hopper and said dome casting.

3. In a fuel burning boiler, a double walled dome casting of cylindrical conformation forming a water jacket and having a vertical collar, a truncated conical magazine hopper secured to said collar and extending downwardly into said dome in spaced relation to its cylindrical wall, an exhaust flue collar integral with said dome communicating with the space between said hopper and said dome wall, a supporting base casting for said dome having a grate supporting ledge, a grate defining an ash compartment and a fire box, a primary air supply opening in said base casting communicating with said ash compartment for supporting combustion on said grate, and a secondary air opening in said base casting in communication with said space.

4. In a water heating boiler, a dome casting comprising a cylindrical conformation of double walled wall structure forming a Water jacket, supply and return ports communicating with the intervening space between the double walls of said casting, a conical fuel magazine supported in concentric vertical alignment within said casting flaring downwardly in spaced relation to the cylindrical wall of said casting, a supporting base for said casting horizontally partitioned to afford a fire box beneath said magazine, means for supplying a primary air supply to support combustion beneath said magazine, and means for supplying a secondary air supply to support combustion of volatile combustibles in the space between said magazine and said cylindrical dome casting wall.

5. A water heating unit comprising a double walled dome casting forming a water-jacket, a refractory lined fuel hopper concentrically mounted in said casting and spaced therefrom laterally to form a combustion chamber contiguous to the inner surfaces of said casting, a base comprising a cylindrical wall section having an opening for admitting air to support combustion in said combustion chamber, a horizontal grate supporting shelf on said base, a grate on said shelf forming a primary combustion zone beneath said hopper and additional air supply means in said base for supporting combustion in said pri mary zone.

6. In a hot Water boiler, a supporting base, an annular ledge interior of said base, a fire grate supported on said ledge and partitioning said base into a fire box and an ash chamber, a cylindrical refractory wall supported on said ledge and spaced from the base wall circumferentially to provide therebetween an air chamber, a double walled heater dome which forms a water jacket nested on said base, a vertical collar on said dome, a sidewardly extending flue collar formed in said dome, a conical hopper suspended from said vertical collar having vent openings which connect the space within said hopper with the circumferential space between said dome and said hopper, said hopper being flared downwardly and extending into said fire box of said base and having an internal lining of refractory material, a cover for said vertical collar and hopper pivotally mounted on said dome, and pairs of threaded embossments integral with said dome and constituting feed and return communication ports with the water jacket of said dome.

ROBERT C. CROSS.

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