US2667158A - Coal burning magazine space heater - Google Patents

Description

COAL BURNING MAGAZINE SPACE HEATER Filed Sept. 16, 1948 3 Sheets-Sheet l a MA) on iM Jan. 26, 1954 DE WlTT H. WYATT COAL BURNING MAGAZINE SPACE HEATER 3 Sheets-Sheet 2 Filed Sept. 16, 1948 gwuonfotz DE W177 H W547? arty/v.05

Jan. 26, 1954 DE wrr-r H. WYATT COAL BURNING MAGAZINE SPACE HEATER 3 Sheets-Sheet 3 Filed Sept. 16, 1948 HG. f.

Patented Jan. 26, 1954 UNITED STATES PATENT OFFICE 2,667,158 COAL BURNING MAGAZINE SPACEHEATER De Witt H, Wyatt, Columbus, Ohio Application September 16, 1948, Serial No. 49,607

2 Claims. 1

This invention relates tospace heaters and, more particularly, to heaters or stoves of the solid fuel burning type, having special reference to room or residence heatersor stoves employin vertical magazine in which coal, or other solid fuels, is introduced and fed gravitationally to combustion grates or zones disposed in the lower portions of such heaters.

It is an object of the invention to provide a coal-burning space heater with improved means for supplying combustion air under regulable iiow to the grate structure and fuel combustion zone of the heater, whereby to var automatically and control the rate-offuel combustion in accordance with fluctuations in room temperature adjacentto the heater.

Another object of the invention is to provide a space heater of the magazine type in which the hot gases of combustion, following'their generation and release from'burning fuel, are caused to flow in intimate contact and heat-exchanging relationship with the heat-conducting walls of a multiplicity of vertically extending channels provided in a radiator disposed within and spaced from an outer casing of the heater, room air being introduced into the bottom of the casing and directed, While traveling upwardly, over the outer surfaces of the radiator, whereby the room air is heated and discharged through outlets provided in the top .of the heater casing.

Other objects are to provide a magazine type heater utilizing solid fuels which is efficient and economical inoperation; one which requires infrequent manual servicing in introducing fuel or removing ash; a heater which does not produce smoke when in operation in the room in which it is positioned; a heater of thecharacter set forth in which automatic draft controls are provided responsive to floor temperatures for regulating the admittance of primary air into the combustion zone of the heater in volumes proportioned to the temperature of the air adpacent to the floor or other base surface on which the heater :is positioned, said controls, further, being responsive to the temperatur of gases passing to the chimney r stack outlet of the heater, whereby to vary th rate of fuel combustion in a manner proportionate to the temperature of the outletgases, and in the provision of a heater generally which may be economically manufactured and sold and which, in use, is

characterized by its freedom from mechanical disorders and thesmallamcunt of manual care- 2 required in maintaining the same in active operation.

This application constitutes a continuationin-part of my prior application, Serial No. 628,443 filed November 14, 1945, now Pat. No. 2,545,680, ranted March 20, 1951.

For a further understanding of the invention, reference is to be had to the following description and the accompanying drawings, wherein:

Fig. 1 is a vertical longitudinal sectional view taken through the heater;

Fig. 2 is a similar view on the plane indicated by the line 22 of Fig. 1;

Fig. 3 is a horizontal sectional view on the plane indicated by the line 33 of Fig. 1

Fig. 4 is a detail vertical sectional view on the line 4-4 of Fig. 1;

Fig. 5 is a diagrammatic view disclosing the automatic damper and valve controls governing the paths of air and gas flow through the heater.

In the specific embodiment of my invention selected for illustration in the accompanying drawings, my improved heater comprises a substantially cubical outer casing l. The casing includes a base structure 2 having united angle members 3 and a horizontally disposed plate v t which defines the bottom of an ash pit 5. The casing I includes a vertical front wall 6, spaced side walls 7 and a rear wall 8, the rear wall having formed therewith a rearwardly projecting draft casing 9, the latter, as shown particularly in Figs. 1 and 3, being of reduced width as compared with that of the casing I. The upper part of the casing supports a hingedl movable top 10, at the sidesof whichare provided stationary grills H for the escape of heated air.

In connection with this outer casing, which is composed mainly of sheet metal plates or members rigidly maintained in their required relative order, the heater embodies an inner casing structure I2, the Walls of the latter being spaced from those of the outer casing to provide spaces S for the travel of air upwardly from the base of the heater to the outlets provided in the grills l 3. During such upward ftravelthe temperature of the air 'israised by contact with heated surfaces ofthe inner casing structure in a manner to be more fully explained hereinafter.

Conveniently, the inner casing structure may be formed to provide vertical ash pit defining Wall members 13 which, at their lower edges, are secured to the base structure 2. As shown in Fig. 2, themembers 13 disposed at the sides of the ash pit 5 term ateat their upper .ends'in inwardly andhorizontally directed flanges Ill. and

downwardly and vertically directed flange l5. Positioned on and secured to the flanges I4 is the metal outer lining 16 of a ceramic fire bowl l1, and in the opening provided in the bottom of this fire bowl, there is positioned an oscillatory grate l8.

Secured to the upper portion of the vertical side members 13 are substantially rectangularly disposed heat-radiating plates l9. Each of these plates, advantageously, may be formed with substantially V-shaped heat-radiating fins 20, which project into the air circulating spaces S to provide greater surface area for contact of the air undergoing heating with the heat-liberating surfaces of the inner casing structure. At their longitudinal ends, as in Fig. 5, the plates [9 include adjoining radially extending flanges 2| which are engaged with vertical stay rods 22 and with which the rounded outer ends of the flanges 2! are held in clamping engagement by means of the threaded fastening elements 23, the upper and lower ends of the rods 22 being secured to bars 24 rigidly attached to flanges provided at the upper and lower flanged edges of the walls of the outer casing.

By reference to Fig. 2, it will be noted that the side and back walls 1 and 8 of the outer casing at their lower edges terminate in a horizontal plane above that of the base structure 2, so that air may be drawn from the floor level and advanced upwardly through the spaces S for heating contact with the walls of the inner casing structure. The base structure along the sides and. back thereof is formed to provide channels 25, and in these channels, there are seated ceramic water Vaporizers 26.

Below the grate iii, the ash pit receives a removable ash pan 21. The front wall of the outer casing, in registration with the ash pit, is provided with an opening for the reception of a removable panel 28, by which access is provided to the ash pit for the purpose of removing or inserting the ash pan. The panel may be formed with inwardly facing gaskets 29 to seal the edges of the opening therefor when the panel is operatively positioned, as shown in Fig. 3.

The plates I9, adjacent to the upper edges of the fire bowl ll are shaped to provide grooves 30. In these grooves, metallic frame bars 3| are seated, the bars resting on the upper of the ceramic bowl [1 and its outer lining. Positioned on bars 3! are the lower and outer surfaces of a plurality of substantially rectangular duct-forming blocks 32 of ceramic composition, these blocks having their inner and side surfaces formed with ribs and grooves 33 which interfit where adjacent blocks meet, as in Fig. 5.

By reference to Figs. 1 and 2, it will be noted that the lower surfaces of these refractory blocks overhang the fire bowl area, and since each block is formed to include a plurality of vertically extending combustion gas passages 34 and combustion air-supplying passages 35, the

lower ends of these passages will be disposed in open communication with the fire bowl, the latter forming the fuel combustion zone of the heater. It will be noted. that the blocks 32 are so arranged as to constitute a vertical fuel magazine with fuel storage capacity. Solid fuels are introduced into the top of this magazine and are fed gravitationally in a downward direction therethrough into the fire bowl with the burning fuel supported on the grate l8. The outer walls of this grate are spaced as at 36 from the adjacent inner walls of the fire bowl l1, so that surfaces primary air for fuel combustion purposes may be drawn from the ash pit, in a manner hereinafter described, and supplied to the burning fuel.

Also, as hereinafter defined, secondary air for fuel combustion purposes passes downwardly through the ducts of the blocks 32 and is combined with the burning fuel to sustain active combustion thereof. Under the normal draft of the heater, these burning gases pass upwardly through the combustion passages 34, heating the walls of the passages and, in turn, the adjoining heat-radiating plates 19 and their fins 20, so that the heat generated by the burning fuel will be transmitted to the room air passing upwardly through the spaces S.

The grate structure It, in this instance, has been shown ascomprising a metallic casting 31 which contains and supports a body 38 of a ceramic refractory, the body being formed with reversely inclined upper surfaces 39, which are adapted to direct ash toward the sides of the grate, so that when the latter is rocked, fine ash may be deposited in the pan 2?. At its front and rear ends, the casting 31 is formed with trunnions rockably supported in bearings 41 carried by the inner casing structure. The front trunnion 40 may have its outer end engaged with the slotted lower end of a link 42 which, at its upper end, is pivotally attached as at 43 to a grate-rocking handle 44. Normally, and as shown in Fig. 3, this handle occupies a downwardly inclined position to the rearof a removable panel 45 positioned in an opening formed in the front Wall of the outer casing I above the ash pit panel 28. When the panel 45 is removed, the handle 44 may be swung upwardly to an operating position.

When in a substantially horizontal position, the bifurcated end 46 of the handle will be removed from engagement with a stationary stop lug 4'! formed with the metallic lining of the fire bowl, thus permitting the handle to be manually actuated to rock the grate on its trunnions 40 and thereby remove ash from the combustion zone. It will be noted that when the handle 44 occupies its lower position, the engagement of the bifurcated end 45 thereof with the lug 41 will retain positively the grate against rocking movement.

The upper portions of the plates l9, adjacent the plane of the upper edges of the blocks 32, are recessed to receive the shouldered and offset lower edges 48 of a plenum ring 49. This ring defines a plenum chamber 58 for receiving the gaseous products of combustion issuing from the upper ends of the ducts 34. The chamber 50 is spaced from the fuel magazine M by a plurality of spaced inwardly disposed divisional plates 5| and 52, the lower edges of the latter resting on upper edge surfaces of the blocks 32, while the upper edges of the plates 5i and 52 engage with inwardly and downwardly directed flanges 53 formed with the plenum ring 49. The flanges 53, as shown in Figs. 1 and 2, terminate in a downwardly directed spout 54 having downwardly and inwardly inclined walls, and by means of which spout, fuels are directed into the upper part of the magazine M. By reason of the inclination of the walls of the spout and the extent to which they project into the top of the magazine, suincient spacing exists between said spout and the walls 52 to form a smoke trap T.

The top It comprises a hollow sheet metal structure, having a finger-gripping recess 55 formed in the front thereof. At its rear, the top is provided'witha'hinge pintle 5B which is received in bearings formed withthe top of the plenum ring 49,- so that by gripping the top with the aid of the recess 55, the same may be raised and lowered, by swinging movement in a vertical plane. The bottom of the top is provided with a lid 51 which seats on a shoulder 58 provided by the walls of the spout 54, so that when the top is lowered, the openable upper end of the magazine will be closed thereby. The lid 57 is connected with the top by means of the fastening screws and nuts shown at 59.

As shown more particularly in Figs. 4 and primary air for fuel combustion purposes enters the lower part of the draft casing 9 by way of an opening 60 in one of the walls thereof. The amount of air passing through this opening is controlled by means of a weight-balanced damper valve 6i suspended from a fixed pivot 62. When the valve Si is open, as in Fig. 4, atmospheric air passes into the lower portion of the draft casing 9 and passes over a baille Wall 63 disposed at the rear of the ash pit 5. By the provision of the walls shown at 64 and 65, a primary air chamber 66 is formed in the bottom of the draft casing 9. The walls 63 and 65 are spaced so that primary air flows from the chamber 66 into the ash pit and thence upwardly around the grate structure into the fuel bed present in the fire bowl I1.

Supported below the bottom wall of the primary air chamber in a position to be responsive to floor temperatures exteriorly of the heater is a bellows-type thermostatic element 61, which expands and contracts in the usual manner in response to temperature variations. The element 6! includes an upstanding rod 68, which engages with a bearing socket provided in one end of a lever arm 69. This arm intermediately of its length is connected with a pivot shaft Hi which, as shown in Fig. 4, is rotatably supported at its ends in bearings H carried by the side Walls of the chamber 66. Adjacent to one of its ends, the shaft 10 carries a crank lever 72 which engages with an offset flange 13 formed with the damper valve Bl, so that as the rock shaft l8 oscillates, in response to the action of the thermostatic element 61, the damper valve 6| will be moved to positions opening or closing the primary air inlet 60. When the air temperature surrounding the thermostatic element 67 is below a predetermined value, the pivot shaft 10 and its crank lever 12 assume positions providing for the automatic opening of the damper valve e: and the flow of combustion air into the heater under the draft flow of the heater. When the room temperature ambient to the thermostatic element exceeds the predetermined value, the element expands to move the valve 61 toward or into a position obstructing the inflow of air into the heater through the opening 60.

Arranged within the draft casing 9 above the walls 64 and 55 is an inclined bafiie 14 which forms a check air receiving chamber 15, the baifle 7d being formed with an opening- 16 providing for the flow ofair from the chamber into a flue chamber 11 provided in the upper portions of the casing 9, the flue chamber being in open communication with the plenum chamber 50 at the rear of the heater. The top of the flue chamber 1! is formed with a waste gas outlet 18, leading to an associated outlet flue or chimney, not shown. The gaseous products of combustion, after traveling through the combustion passages 34 of the blocks 32, enter the plenum chamber and thence travel into the flue chamber 11, leaving the heater by Way of the waste gas outlet 18.

As the waste gases travel through the flue chamber, and before entering the outlet 18, the same pass over a thermostatic element 19. This element includes a manual control in the form of the externally positioned knob, indicated at 86, so that the element 19 may be adjusted for obtaining heater response to different operating temperatures. The movable part of the element '9 includes a depending rod 8| which, at its lower end, has a pivotal connection with one end of the lever arm 69 opposite to that with which the rod 68 is associated. By the adjustment of the knob 80, the draft controls of the heater may be manually regulated to maintain substantially uniform any desired temperature within the working range of the heater. The thermostat I9 is of the bellows type, specifically disclosed in my aforesaid prior copending application, involving an expanding bellows element. The floor thermostat 61 is also of the bellows type, the two thermostats, 61 and E9, operating conjointly in response to temperature conditions prevailing adjacent the floor of the heater and in the flue chamber 71 to regulate the operation of the various Valves of the heater, shown at 6!, 84, 90 and 96', in obtaining a regulated delivery of heat in response to changing room temperatures. 7 7

Thus, if the temperature of the gases passing over the thermostatic element 79 should exceed a predetermined value, said element responds to depress the rod 8|, which rocks the lever arm E9 and the pivot shaft 10 in adirect causing the crank lever 12 to elevate a rod 82 connected therewith. This rod is engaged with an ofiset flange or lip 83 provided on a pivot check airregulating valve 84. This valve 'normally closes an opening 85 provided one of the side walls of the chamber 15. The elevation of the rod 82 rocks the check air valve about its pivot 85, thereby permitting air to be drawn from the atmosphere into the chamber 15 and thence into the flue chamber 11.

At the same time, the oscillation of the lever arm closes or partiallycloses the opening 65 through the associated operation of the damper valve 6|, causing a lower rate of fuel combustion in the fire bowl of the heater. If desired, the lever arm 69 may have the weight thereon counter-balanced by a coil spring 87, so that it soperation takes place freely and easily and in ready response to the controls provided by the thermostatic elements 6? and I9 and their respective parts.

Secondary combustion air isadmitted into the chamber 38 formed between the walls 5! and 52 by means of an air inlet '89 provided in the top of the plenum ring 49. This inlet is opened and closed by a valve shutter 9-9 which turns about a pivotal mounting Si. in order to provide for automatic control over the operating positions of the shutter 90, there is connected with its pivotal mounting a depending crank arm 92'. The lower end of this crank arm, as shown in Fig. 5, is pivotally joined at one end of a link 93, the other end of said link being pivotallyconnected with the longer arm of a b'ell'cranl-z lever 95. The shorter arm of this lever in confined between spool-forming collars 55 on the rod 81 of the thermostatic elements 19, so that the valve shutter Siiwill assume open or closed positions with respect to the air inlet '89 in "accordance with the opening and closingof the primary air-valve 6|.

To prevent the escape of smoke from the upper portion of the fuel magazine and its release into the room atmosphere, particularly under conditions where a fire is being freshly started in the heater and while the outlet fiue or chimney may be at a low temperature and not properly warmed, I provide a by-pass valve 96 which is pivotally mounted as at 91 to open or close an opening 98 formed in the wall 52 adjacent to the top of the fuel magazine. Normally, the by-pass valve 96 is closed but under conditions which produce the presence of smoke in the upper part of the fuel magazine, the lever 94 is rocked so that a link 99 connected with the longer arm of said lever is moved to assume a position opening the by-pass valve and providing for the convenient escape of smoke into the plenum chamber and thence to the waste gas outlet of the heater. When normal draft conditions obtain with accompanying fuel combustion rates and draft pull through the heater, the by-pass valve is closed.

Consideration of these features of construction and operation will make it clear that the present invention provides a coal-burning room or space heater which may be maintained in operation over relatively prolonged periods of time without requiring manual attention. The usual coalburning heater of thi category requires frequent manual attention in the matter of replenishing the coal supply and in adjusting draft controls to secure desired rates of fuel combustion and room temperatures.

In the present heater, the magazine M, after a fire has been initiated in the combustion bowl, may be filled to the limit of its storage capacity. As the fuel is consumed, through combustion, the same gradually settles in the hopper toward the fire bowl, maintaining in the latter at all times a proper amount of fuel for combustion-sustaining purposes. As the coal or other fuel thus settles, its temperature is gradually increased. The freely removable volatiles contained therein are first distilled off in the form of gases 01' vapors, and under draft pull of the furnace pass along the grooved surfaces 33 of the blocks 32 and, upon ignition, enter the combustion passages 34, burning actively in these passages.

The solid fuel in the combustion zone, provided by the fire bowl, is substantially in the form of coke and burns freely with a minimum of coarse ash or clinker formation. The walls of the blocks 32 become highly heated by fuel combustion taking place in the passages 34, and this heat is transmitted by conduction, convection and radiation to the air drawn from the floor of the room and passing upwardly through the spaces S around the heat radiating plates 19, their fins and the walls of the plenum ring 49.

If desired, the hollow fins 20 may be filled, as indicated at I09, with a heat-conducting material. Usually thermal circulation of the air undergoing heating is all that is required in the average installation, although it is within the scope of the invention to employ conventional forced circulation of the air if such should be desired. It will also be noted that air for combustion regulating and modifying purposes is introduced into the heater at three different levels.

First: the primary air for fuel combustion purposes enters the heater from about the fioor level thereof, as provided by the opening second, the check fuel combustion air enters the casing by way of the opening 85, which is disposed at a higher level in the flue casing than the primary air opening, and, third, secondary air for fuel combustion purposes enters the casing through the air inlet 89 at the top thereof. By locating the thermostatic control element 61 adjacent the floor level, the operation of the heater is rendered more satisfactory to room occupants. Under normal draft pull, smoke or volatile fuel particles contained in the bowl of the magazine is drawn downwardly and prevented from passing in an upward direction. It is only when abnormal draft conditions are present that the by-pass valve 96 need be opened.

It will be noted that the air undergoing heating, passes upwardly throughout substantially the complete height of the heater, thus having ample opportunity to contact the heat-releasing surfaces thereof to provide for efiicient heat interchange. Through the operation of the automatic draft controls, the heater will maintain uniform room temperatures which are in marked contrast with the highly fluctuating temperatures provided by ordinary heaters having manually regulated draft controls. The mechanical structure of my improved heater is essentially simple and readily assembled, so that the same may be economically manufactured and sold. Materials have been selected, such as the employment of the refractories provided in the construction of the grate 18, the fire bowl I! and the blocks 32 which highly resist deterioration from high temperatures. Otherwise, sheet metal is largely used in the construction of the heater for reasons of manufacturing economy. Over the opening it in the baflle M, a shield 0| may be placed to prevent light ash contained in the flue gases from depositing in the checking air chamber. The removable panel doors are provided in the front opening of the ash pit and the grate shaker for the purpose of normally closing the front of the outer casing and enhance its appearance. Similarly, the lid for the fuel inlet of the magazine is pivotally mounted on the swinging top, adding symmetry to the external lines of the outer casing. Adjacent to the primary air inlet, the draft casing 9 may be provided with an access door I92 so that convenience may be had in adjusting the thermostatic controls present in the primary air chamber. Usually these adjustments are factory or service mens adjustments and ordinarily it is only necessary for the user of the heater to provide desired temperature ranges through adjustments of the knob 90 of the thermostatic element l9.

Iclaim:

1. In a coal-burning heater, a main casing structure formed internally to provide in vertical superposed order an ash pit, a grate, a fire bowl and a fuel magazine; said magazine having a refractory lining formed with a plurality of open-ended passages for the transmission of burning and heated combustion gases and with a plurality of open-ended adjacent passages for the transmission of combustion air to said fire bowl; spaced inner and outer divisional plates mounted on said refractory lining and defining between them an air chamber in the top of said heater which is'in open communication with the passages of said lining employed for the transmission of combustion air; said chamber having an air inlet, a valve member for said air inlet which when open provides for the passage of air from the atmosphere downwardly through said air chamber and. through the air-conducting passages of the refractory lining to the fuel contained in said fire bowl; a plenum chamber having a flue outlet formed in the top of said heater casing around the outer of said divisional plates, said plenum chamber being in communication with the open upper ends of the flame and combustion gas passages of said lining, and thermostatic means disposed in heat-exchange relation to flue gases present in said plenum chamber and responsive to predetermined increase or decrease in the temperature of said gases for decreasing or increasing the quantity of air admitted by said valve member into said air chamber.

2. In a coal-burning heater, a main casing structure formed internally to provide in vertical superposed order an ash pit, a grate, a fire bowl and a fuel magazine; said magazine having a refractory lining formed with a plurality of open-ended passages for the transmission of burning and heated combustion gases and with a plurality of open-ended adjacent passages for the transmission of combustion air to said fire bowl; spaced inner and outer divisional plates mounted on said refractory lining and defining between them an air chamber in the top of said heater which is in open communication with the upper ends of the combustion air passages of the lining; said chamber having an air inlet, a valve member for said air inlet which when open provides for the passage of air from the atmosphere downwardly through said air chamber and through the air-conducting passages of the refractory lining to the fuel contained in said fire bowl; a plenum chamber having a flue outlet formed in the top of said heater casing around the outer of said divisional plates, said plenum chamber being in communication with the open upper ends of the flame and combustion gas passages of said lining; thermostatically operated means responsive to the temperature of gases present in said plenum chamber and the outlet thereof for operating said air inlet valve member to increase or decrease the amount of combustion air entering the air chamber and delivered by said combustion air passages to the fire bowl; means forming a smoke outlet leading from said inner divisional plate to said plenum chamber, a second movable valve member for closing said smoke outlet, and link devices actuated by said thermostatic means for operating the valve member of said smoke outlet.

DE WI'IT H. WYATT.

References Cited in the file of this patent UNITED STATES PA'IENTS Number Name Date 888,109 Moon May 19, 1908 1,16 ,672 Hill Nov. 23, 1915 1, 08,432 Wiley Dec. 12, 1916 1,732,167 Pence Oct. 15, 1929 2,151,5 2 Hagen Mar. 21, 1939 2,302,197 Edwards Nov. 17, 19% 2,329,993 Kriner Sept. 21, 1943 2,345,519 Wingert Mar. 28, 1944 2,367,165 Astradsson Jan. 9, 1945 FOREIGN PATENTS Number Country Date 660,540 Germany Feb. 12, 1936

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