US2086621A

US2086621A - Apparatus for burning solid fuel

Info

Publication number: US2086621A
Application number: US704288A
Authority: US
Inventors: Rutherford H Hunter
Original assignee: Individual
Current assignee: Individual
Priority date: 1933-12-28
Filing date: 1933-12-28
Publication date: 1937-07-13
Anticipated expiration: 1954-07-13

Description

July 13, 1937. R Q TE 2,086,621

APPARATUS FOR BURNING SOLID FUEL Filed Dec. 28, 1953 5 Sheets-Sheet 1 j" 1 M MM I s IN VENT A TTORNEY July 13, 1937. v R, H, HUNTER 2,086,621 7 APPARATUS FOR BURNING SOLID 'FUEL Filed 'Dec. 223, 1953 5 Sheets-Sheet 2 R H HUNTER IN VEN TOR A TTORNEY July 13, 1937. R, H, H NTER 2,086,621

APPARATUS FOR BL IRNING SOLID FUEL Filed Dec. 28, 1935 5 Sheets-Sheet 3 as 35 a m RHHUNTER IN VEN TOR A TTORNE Y July 13, 1937. HUNTER 2,086,621

APPARATUS FOR BURNING SOLID FUEL Filed Dec. 28, 1933 5 Sheets-Sheet-4 a 10 R H HUNTER IE INVENTOR iii/44W A TTORNEY July 13, 1937. R. H. HUNTER APPARATUS FOR BURNING SOLID FUEL Filed Dec. 28,. 1933 5 Sheets-Sheet 5 IN VEN TOR A TTORNEY i atentecl July 1?, 1 937 UNITED STATES PATENT OFFICE 20 Claims.

This invention relates to improvements in apparatus for burning solid fuel, and while intended for use generally wherever it may be advantageously employed, it is particularly adapted for embodiment in a hot air furnace in which connection it will be illustrated in drawings and hereafter described:

Objects of the invention which may be considered collectively and independently are:

To provide a solid fuel burning apparatus of simple, durable construction which will be extremely economical in operation and very efficient in use; to provide a furnace havinga chamber adapted to hold a supply of solid fuel; to provide efficient means for progressively feeding the fuel to a retort or combustion chamber; to

provide efiicient means for cooling said hopper and maintaining the same at a relatively low temperature; to provide highly eflicient radiatingmeans for heat generated in said combustion chamber, and to provide a combustion chamber which will effect a maximum consumption of gases generated by combustion and will reduce to a minimum the smoke emitted therefrom.

Other objects and advantages of the invention will be understood from the following description taken in connection with the accompanying drawings in, which there is shown an illustrated embodiment thereof, it being understood that the invention is not confined to the particular adaptation illustrated, and that changes and modifications may be made or resort had to substitu- .tiOns which come within the scope of the claims l'hereinto appended.

In the drawings like characters of reference are employed to designate like elements as the same appear in the several views.

Figure l is a front elevational View of a hot :air furnace constructed in accordance with this invention;

Figure 2 is a horizontal sectional View taken as indicated by the line 2-2 of Figure 1;

Figure 3 is a vertical sectional view taken as indicated by the line 3-3 of Figure 1;

Figure 4 is a vertical, sectional view taken as indicated by the line 4.i of Figure 2;

Figure 5 is a horizontal, sectional view taken as :i-ndicatedby the line 55 of Figure 4;

Figure 6 is a fragmentary view showing in vertical section certain portions of the device herein disclosed;

.Figure 7 is a fragmentary view taken in horizontal section as indicated ,by the lines 1-! of Figure 3,

Figure 8 is a plan view of the feeding cam eni-' ployed in reducing the invention to practice,

Figure 9 is a bottom view of same,

Figure 10 is a plan view showing part of the operating mechanism employed in carrying out the invention;

Figure 11 is a front, elevational View of the centriiugally operating clutch collar employed in the draft operating mechanism herein described.

In the particular embodiment of the invention shown in the drawings, there is illustrated a base section comprising a bottom plate H] having parallel upstanding flanges H and 52, forming a groove 13 therebetween for receiving the lower edge of the ash pit section M. The rearwardly l presented portion of the ash pit section I 4 corresponds in shape to approximately one-half of a hollow frustum of a cone, positioned with its smaller diameter at the upper end thereof.

The walls of the section M extend forwardly in the form of a rectangular box-like extension l9 leading to a forward wall [6 which is provided with a door opening I! whereby access may be had to the ash pit P5. The opening H is provided with an ash pit door 18 which in turn is provided with a draft opening and a draft door 28. The

. upper wall of the box-like extension i9 and the upper edge of the rear half of the section id are provided with a groove 22 for receiving the lower portion of the section 25.

The numeral 25 denotes a retort or fire box section in the form of a hollow truncated cone which is positioned on the section [4 with the lower edge portion thereof received in the annular groove 22.

The section 25 is relatively thicker at the upper edge thereof, being provided with an outwardly projecting circumferentially extending flange 26. The section 25 is provided in the upper edge thereof with a concentrically arranged annular groove 21.

Numeral 28 denotes a middle section which is also in the shape of an inverted hollow truncated cone, having its lower edge portion entered in the groove 2? of the section 25. The upper edge portion of the section 28 is provided with an outwardly projecting circumferentially extending flange 29 which is provided in the upper edge thereof with a concentrically arranged groove 38.

The section 28 is provided at the forward side thereof with a box-like extension 3! which leads to the opening 34 in the forward wall it, thereby providing means whereby access may be had to the combustion chamber 32. A suitable door 33 is hinged to the forward walls l6 to close the opening 32.

The numeral 35 denotes a section which forms the top and the inner wall which incloses the annular combustion chamber 32.

The section 35, as shown in the drawings, 'is cast in one piece and includes the upper wall 350 in the form of a hollow truncated cone. The outer edge of the wall 35a is provided with a circumferentially extending downwardly presented flange 36 which is received in the groove 38 in the upper edge of the section 28. The section 35 also includes an inner Wall which. follows the contour of an inverted hollow truncated cone which extends downwardly and terminates in an inwardly curved portion 350 which is positioned in a horizontal plane just above the horizontal plane of upper edge of the section -,l4. The reference character 35d denotes a cylindrical portion which is continued upwardly, which meets the curved portion 350 at a sharp angle and projects upwardly therefrom, thus forming a cylindrical feed cavity 37. The cylindrical portion 3511 is offset smallerat the upper end thereof topmvide an annular shoulder 38 on the exterior surface thereof, and with a downwardly presented, annular shoulder thereof.

The portion of the section 35d extending above the shoulder 39 is solid and is provided with an axial bore 4!]. and a plurality of openings 4| which extend vertically therethrough, and are arranged in spaced relation around the bore 48. The openings 6! may be of any suitable crosssectional shape, and are preferably tapered with the smaller end of the openings presented upwardly.

The central portion of the wall 35b is enlarged hollow truncated cone 45 is positioned within the 1 conical portion 35b to inclose the space 46.. The wall 351; is provided along a horizontal plane substantially coincident with the plane of the upper edge of section 25, with the circumferentially extending series of spaced openings 41 forming passages which communicate with the enclosed space 46- and the combustion chamber 32.

The enlarged portion of the wall 35bisextended outwardly, then inwardly at a sharp angle to form the substantially annular portion 35c and to provide an enlargement of the space 46 for the purpose to be herein and after described.

The numeral 56 denotes a conical hopper, which terminates at the lower end thereof with the hollow cylindrical portion which is fitted over the reduced upper end of the cylindrical portion 35d. The conical portion 50 of the hopper terminates at the upper end thereof in a cylindrical portion 52' in which is fitted a hollow cylinder 53.

The cylindrical portion 53 is closed at the upper end thereof with a wall 54 which projects outwardly beyond the outer edge of the cylinder 53 and extends forwardly and terminates in a shelf, which is supported by the forward Wall IS.

The upper wall 54 is provided with a bore 55 which is positioned to receive a tubular shaft 56, which extends axially through the cylindrical portion 53 of the hopper 56. The shaft 56 which extends through the bore 55 and projects upwardly beyond the top'54 and is provided on the upper end thereof with a wheel 5'! which is fixedly secured thereto, a suitable anti-friction bearing 39 on the interior surface 58 being mounted between the lower face of the hub of the wheel 5'! and the top 54.

The numeral 66 denotes a disk which is fitted on the shaft 56 and which covers the reduced upper end of the cylindrical portion 35d. The disk 60.

frictionally secured to the shaft 56 by means of bolts 63 which are mounted in suitable openings in the radial wings 62a whereby the collar 62 will 7 The collar 62 is pro:

turn with the shaft 56. vided on the lower edge thereof with a downwardly projecting lug 64 which is entered in a suitable notch 85 in the plate 66 whereby the plate 66 will turn with the shaft 56.

The shaft 56 is provided with a similar disk 66 which is positioned against the shoulder 39 on the reduced portion 35d to cover the lower ends of the openings 4|. provided with an opening 6'! which may be of any suitable shape and through which fuel. will be successively released from the'lower ends .of the openings at. The opening 61 in the plate 66 is positioned diametrically opposite-the openings 6! in the plate 60. V

The shaft 56 is provided at the lower end thereof with a cam feed wheel 10' having a hub II. The numeral 12 denotes a collar which is similar to the collar 62 and which extends between the plate 66 and the hub ll. The collar 12 is split and is provided with radial flanges T3 for receiving the bolts Hi, which are employed to frictionally secure the collar 12 to the hollow shaft 56.

The plate 66 is also The collar T2 is provided at'the upper end' thereof with a lug 15, which'is received in a notch 68 in the plate 66 to provide a'positive driving connection between the plate 66 and the shaft 56. The collar lZis likewise provided. on the lower edge thereof with downwardly projecting lugs, which are received in seats 11 in the cavity. Each arm on said cam feed wheel 16 is provided on the force exciting side thereof with a downwardly depending flange 10bwhich extends between the top wall of'each arm and the grate to be hereinafter described. The inner end portions of the flanges 16b are disposed in concentric relation to the hub H thereby forming an annular cavity 160. i

The numeral 86 denotes a hollow shaft which is rotatably nested in. the bore of the shaft 56 and which projects from each end thereof. The shaft 86 is provided on the upwardly projecting ehd thereof with a wheel 8i, a suitable antifriction bearing 82 being employed between the hub thereof and the wheel 51. v

A circular grate 83 issecured to the lower en of the shaft 86. While any suitable circular grate may be employed, in the drawings there'is shown a grate 83 having a central portion 84 which is secured to the'shaft 88 by means-of the pin 65. or other suitable means.v The central portion of the grate 83 is preferably'solidand is provided with a downwardly offset marginal portion 86. The numeral 8! denotes the annular outer portion of the grate 83. The annular portion 81 is provided with a downwardly inclined inner marginal edge which is supported on the marginal portion 86 of the portion 83 a layer of fire clay or suitable fire resistant cement 88 being employed to firmly hold the portion 81 on the portion 84. The annular portion 81 is provided with suitable radial slots 89 forming bars therebetween.

The top wall 350. is provided at the rearwardly presented side thereof with an upwardly presented nipple 90 having a bore 9| communicating with the combustion chamber 32. The numeral 92 denotes an elbow which is operatively connected to the upper portion of an outlet box 93. The outlet box is provided at each lateral side thereof with an extension in the form of a rectangular box 94 which conforms to the shape of the casing 95. In the particular adaptation of the invention the casing 95 is of hexagonal shape and the boxes 94 extend forwardly, in parallel relation to the lateral sides thereof, terminating in the closed ends 94a. The numeral 95 denotes a horizontal partition which extends through the outlet box 93 and is continued through the extension boxes 94 to a point adjacent the forward ends thereof thereby forming an upper chamber 91 and a lower chamber 98 which communicate at the forwardly presented ends thereof thereby forming two continuous smoke passages. The outlet box 93 is provided on the rear side thereof with two smoke flues 99 and I00. The flue 99 communicates with the upper chamber 91 and is positioned directly opposite the discharge end of the elbow 92. The flue I00 is positioned below the flue 99 and communicates with the lower chamber 98.

The upper flue 99 is provided with a suitable damper IOI and both of the flues 99 and I00 are operatively connected to a chimney or to a smoke pipe leading thereto.

It will be seen that when the damper IOI is operated to an open position that the smoke and unburned gases generated by combustion will escape directly through the flue 99. When the damper I05 is operated to close the outlet flue 99 the smoke will travel through the chamber 91 to the forwardly presented ends of the boxes 94 and through the chamber 98 through which it will travel and escape through the flue I00.

The tubular shaft 80 is provided at the top thereof with a closure disk I04 having spaced, spring prongs I05 which are entered in the upper end of the bore of said shaft whereby the disk I04 may be operated to entirely close the upper end of said tubular shaft 80 or adjusted to regulate the amount of air admitted thereto. The shaft 80 is open at the lower end thereof thereby providing a trickle draft which may be accurately regulated by manipulating the disk I04.

The wall of the tube 80 is provided with open.- ings I06 through which air will be admitted to the hub cavity 100 of the cam 10.

The wall of the upper portion 53 of the hopper 50 is provided at the forwardly presented side thereof with a box-like extension which leads to the door opening I08 in the wall I8 through which coal or other solid fuel is admitted to the hopper 59. The opening I08 is provided with a suitable door I09 which is hingedly mounted on the wall I6.

One side wall of the extension I01 is provided with a screened opening H0 and a tube II I is operatively secured in said opening. The tube III leads to the wall of the truncated cone 45 and is operatively secured thereto so as to communicate with the cavity 46. The door I 09 is provided with an elongated opening II2 for admitting air to the tube III whereby air will be drawn through the openings 4! to assist in the burning of unconsumed gases in the combustion chamber 32. The numeral 1 I3 denotes a damper or .valve which is operatively mounted in the tube H I and the numeral H4 denotes a damper shaft which projects through a suitable bore in the forward wall I6 and is provided with a knob H5 which may be operated to regulate the opening in the tube III.

The numeral I It denotes a shell which is substantially larger than the cylindrical portion 53 and is secured to the top wall 54 to extend downwardly therefrom in spaced parallel relation to the walls of the portion 53 and in spaced relation to the hopper 50 thus providing a space In. The top wall 54 is provided with a slot I I8 which communicates with the space Ill. The lower end of the shell I IS terminates in spaced relation to the rounded portion 350 and forms a space I89 which communicates with the space II'I thereby forming a continuous passage through which air will be drawn downwardly through the opening M8 to the bottom of the cavity of the section 35 whereupon it will be heated by confact with the wall of the section 35 and will travel upwardly through the space H9. Means is thus provided for maintaining fuel in the hopper 50 at a relatively low temperature and for o preventing the overheating of the portions of the wall of the section 35 which are subjected to high temperature. The wheel 51 is provided with a suitable clutch band I20 which is held in place thereon by means of the clips I2I or other suitable means. The band I20 is provided on one end thereof with a suitable eye I22 which is secured to one end of a lever I23. The other end of the band I20 is provided with an outwardly projecting arm I24. The arm I24 is provided with an ear 425 which projects over the lever I23 and is pivotally secured thereto at a point intermediate the length of the lever I23.

The numeral I26 denotes an electrically operated motor and the numeral I27 2. suitable reduction gear unit. The reduction unit I2! is provided with an eccentrically mounted wheel I28 which is driven by the motor 26. The wheel I28 is provided with a collar I29 and the collar I29 is provided with an outwardly projecting pitman I30. The outer end of the pitman I30 is pivotally secured to the lever I23 by means of the pin I3I whereby the motor H8, when operated, will cause rocking the lever It will be seen that when the pitman I30 is operated to exert a pulling force on the outer end of the lever I23 that the band I20 will be contracted and that the wheel 51 will be given a short clockwise rotary movement. As the wheel 51 is thus intermittently moved by the operation of the motor I26, the movement is communicated through the shaft 56 to the feed cam 10. The disks 69 and 65 are likewise driven by said shaft through the operation of the motor I26.

The wheel 3! is provided with a similar band I 32 which is held in place thereon by the clips I33 or other suitable means. The band I 32 is provided at one end thereof with an ear I 34 to which is pivotally secured a lever I35. The other end I 32 of the band is provided with an outwardly projecting ear I 35 which is pivotally secured to the lever member I35. The numeral I31 denotes a brake operating rod which when a pull is exerted thereon moves the -member I35 to contract the band I32 and move the wheel 8| in a direction opposite the described movement of the wheel 51.

The numeral I38 denotes a bracket which is secured to the top wall and which projects over the rim of the wheel 51. A short lever I39 is fulcrumed to the lower side of the bracket I38 for movement in a horizontal plane. The rod I31 is connected to one end of the lever I391 The other end of the lover I39 projects over the rim of the wheel 51 and is provided with an inclined face which is adapted to be engaged by a pm I49 which is inserted in a suitable 'bore in the rim of the wheel 51. It will be seen that the wheel 51 when intermittently operated as here inbefore described will, upon each rotation, bring the pin I49 into contact with the inclined face of the lever I39, and cause a quick movement of said lever on the bracket I38. This movement will operate to contract the brake I32 and move the wheel H in a direction opposite the direction of movement of the wheel 51. The wheel 9I, being thus moved at each rotation of the wheel 51, causes a similar rotatable movement of The drive shaft I4I of the motor I25 projects from the forward side thereof and is provided with a hub I42 on which is rotatably mounted acollar I43. The collar I43 projects forwardly from the forward face of the hub I42 to expose the inner circumferential edge of the collar I43. Two flat members I44 and I45 which are spaced apart and fulcrumed at opposite ends thereof to the forward face of the hub I42. Each of the members I 44 and M5 is provided with a rounded face adapted to fit against the inner circumferential edge of the collar I43. The members I44 and I45 are normally held out of contact with the collar I43 by a spring I46 which is secured to each of said members. A draft operating device I41 is provided with a drive wheel I48 which is operatively connected to the collar I43 by the drive belt 549. It will be seen that the operation of the motor I26 will cause the members I44 and I45 to be forced outwardly by centrifugal force into engagement with the collar I43, thus rotating the collar with the hub I42 and operating the draft operating device I41. The draft operating device I41 shown consists of a reel on which is wound a chain I59, which is operatively attached to the draft door 20. When the draft door has been raised to its limit the members I44 and I45 will slip in the collar thereby hold- 'ing the draft door 20 in an open position as long as the motor I26 is operated. When the motor I26 is not in operation the spring I46 will move the members I44 and I45 toward each other releasing the collar I43 and permitting the draft door 29 to fall to a closed, position.

The outer casing or jacket may be of any suitable shape or design and may be formed of any suitable material. In the drawings there is shown a hexagonal jacket 95 consisting of the front wall I 6 and five panels I6a of approximately the same size, which are supported at the corners by the posts I53 preferably in the form of angle bars as shown in the drawings. The panels I6a, extend upwardly to the horizontal plane of the top wall 54 and are provided at the upper edge thereof with an inwardly projecting flange I54.

The numeral I 55 denotes suitable cold air inlet openings which are formed in one or more of the panels I6a of the jacket 95 adjacent the lower edges thereof.

The numeral I56 denotes a manifold in the form of a box having'an outer wall I51 supported on the flanges I54; a. relatively shorter inner wall 7 I58 supported on the marginal portion of the top.

wall 54 and an inclined top wall I59. .The main portion of the inner wall I58 is of cylindrical contour and is disposed in alignment with the casing II6'. Each end'ofthe manifold I56 terminates in an end wall I66 which walls are parallel and are disposed in the extended plane of the side walls of the extension I01. The numeral I69a denotes the front wall of the manifold I56 which is positioned in parallel, spaced relation to the plane of the front wall I6. The outer wall I51 of the manifold|56 is provided with suitable distributing openings to which suitable pipes I6! may be connected to operatively connect the furnace to a heating system. Coal or other solid fuel of suitable fineness is placed in the hopper 59 through the door opening I98.

The motor I 26 is operatively connected to a source of electrical energy, thusimparting a series of regularly recurring rotary movements 'to the wheel 51. and causing a like movement of the plate 66. As the opening 6| in the plate 69 passes over each chamber 4I'the chamber is filled with fuel. As the opening 61 in the plate 66 is diametrically opposed the opening 6| the contents of each chamber 4| will be discharged when the opening 61 registers therewith.

The fuel falls downwardly and is deposited on the solid central portion 84 of the grate 83. As I the cam'19 is fixed to the shaft 56, it is likewise rotated thus forcing the fuel outwardly on to the grate 83. When a suificient quantity of fuel has been thus fed to the combustion chamber 32, access is had thereto through the door 33 and the fuel is ignited. As the central portion of the grate is solid the area of combustion will be substantially confined to the vicinity of the annular portion of the grate containing the radial slots 89. With each rotation of the shaft 56 the pin I49 engages the lever E39 and contracts the brake band I32 thus imparting a sudden opposite rotary movement to the shaft 89 and to the grate 83 whereby ashes will be sifted through the slots 89 and will fall to the ash pit I5. 4

It will be seen that while the motor I26 is operating that the draft door 29 is held' in an open position as hereinbefore described. Obviously, the motor I26 may be controlled by a thermostatic apparatus positioned in the area to be heated and operatively connected in an electric circuit with the motor I 26.

During the operation of the apparatus herein described, air will'pass downwardly through the openingI I8'to the space I I 1 and will pass around the lower edge of the casing .I I6 to the space II9 where it will be heated and will flow upwardly to Air will pass chamber 32. The air thus drawn into the combustion chamber is preheated and will readily ignite the unconsumed gases of combustion, rendering combustion so complete that visible smoke is practically eliminated.

It will be noted that the collar 62 is provided with a radial flange 62a and the collar '12 with a like flange 13 which will prevent fuel from clogging in the cavity 31 of the feed section 35d.

With the damper IDI set to close the pipe 99, the heated gases of combustion will travel the full length of the passages 91 and 98 of the boxlike extensions 95 and through the flue E00 to the chimney, thus providing highly efiicient radiating means for heat generated within the combustion chamber 32.

In the specifications and claims, the word hopper is intended to include any form of fuel holding device, the words annular combustion chamber are intended to include a chamber having similarly arranged walls of any suitable shape.

Having thus illustrated my invention and described the same in detail, what I claim as new and desire to secure by Letters Patent is:

1. In apparatus for burning solid fuel, an outer wall of inverted, frustro-conical shape, a top wall and an inner wall of frustro-conical shape said walls connected to form an annular combustion chamber, a grate at the bottom of said chamber, a tube formed integrally with said inner wall and projecting upwardly from the lower edge thereof, means for feeding fuel through said tube'to the central portion of said grateand means to force the same outwardly intosaid combustion chamber.

2. In apparatus for burning solid fuel, a suit -able'shell having an inverted frustro-conical inner wall said shell having walls enclosing an annular combustion chamber, an annular grate at the bottom of said chamber, said grate including a solid plate positioned directly under the conical cavity of said inner'wall, a tube for feeding fuel to said grate, said tube extending downwardly through said cavity in spaced relation to said inner wall and a rotary feeding cam for progressively forcing said fuel outwardly from said plate into said combustion chamber.

3. In an apparatus for burning solid fuel, an upright outer wall, a top wall and an inner wall enclosing an annular combustion chamber, a circular grate at the bottom of said chamber,

means to impart an intermittent rotary move- 'ment to said grate, a rotary cam for moving fuel in an outwardly progressing band from the central portion of said grate to said combustion chamber and means to impart an intermittent rotary movement to said cam in a direction opposite the direction of rotation of said grate.

4. In an apparatus for burning solid fuel, walls enclosing an annular combustion chamber, a circular grate at the bottom of said chamber, means from the central portion of said grate to said combustion chamber and means to impart a rotary movement to said rotary member in a direction opposite the movement of said grate.

5. In apparatus for burning solid fuel, walls enclosing an annular combustion chamber, a rotary grate at the bottom of said chamber, said grate having a solid, central portion; means to feed solid fuel to said central portion rotatable, feedingmeans for progressively moving fuel from said central portion outwardly into said combustion chamber and means to rotate said grate and feeding means in opposite directions.

6. An apparatus for burning solid fuel, walls enclosing an annular combustion chamber, an annular grate rotatably mounted at the bottom of said chamber, said grate including a solid center plate supporting said grate, means to feed solid fuel to said center plate, a rotatable cam for progressively moving fuel from said center plate outwardly into said combustion chamber and means to rotate said grate and cam in opposite directions.

7. An apparatus for burning solid fuel, an outer wall, an upper wall and an inner wall said walls connected to form an annular combustion chamber, a circular grate at the bottom of said chamber, the inner wall of said chamber extending downwardly to a plane in close, spaced relation to said grate; a hopper mounted within said inner wall for feeding fuel to the central portion of said grate the wall of said hopper spaced inwardly from said inner wall and a cam feeding wheel mounted between the lower edge of said inner wall and the central portion of the grate; means to intermittently release a predetermined quantity of fuel from said hopper to the central portion of said grate and means to provide a relative rotary movement of said feeding wheel and grate to move the fuel thus deposited on said central portion outwardly on said grate.

8. A furnace having an annular combustion chamber, a grate at the bottom of said chamber, an inner wall in the form of an inverted, truncated cone extending downwardly to a plane in close spaced relation to said grate, a fuel supply tube formed integrally with and extending upwardly from the lower edge of said inner wall with the main body of the tube spaced inwardly from said inner wall and means to intermittently feed fuel to said fuel supply tube.

9. A furnace having an annular combustion chamber, a grate at the bottom of said chamber, said chamber having an inner wall in the form of a hollow inverted truncated cone which extends downwardly to a plane adjacent said grate; a tubular extension extending upwardly from the lower edge of said inner wall; said extension terminating at the upper end thereof in a solid end portion; a hopper mounted on said solid portion, a plurality of openings forming circumferentially spaced pockets extending through said upper end portion, means to successively release the fuel from said pockets into said tubular extension and deposit the same on the central portion of said grate and means to force the fuel thus deposited in an outwardly expanding band on said grate.

10. In an apparatus for burning solid fuel, a suitable shell enclosing an annular combination chamber, the inner wall of said shell projecting downwardly in the formv of an inverted, hollow truncated cone to a plane adjacent the bottom of said chamber; tubular feed portions projecting upwardly from the lower edge of said inner wall; said feed portions having a solid upper end portion provided with a plurality of chambers spaced around the center thereof and extending vertically therethrough; a hopper supported on said feed portions, a vertical shaft projecting through said hopper and feed portions;

'means associated with said hopper for rotatably supporting said shaft; a solid plate secured to said shaft in a plane directly below the discharge end of said feed section; an annular grate at the bottom of said combustion chamber, said grate operatively mounted on said plate; means on the top of said hopper to impart a rotary movement to said shaft and cause a corresponding movement of said grate.

11. In an apparatus. for burning solid fuel, a suitable shell enclosing an annular combustion chamber, the inner wall of said shell being substantially of frustro-conical shape with the truncated end thereof directed downwardly and terminating in a plane adjacent the bottom of said chamber, a tubular feed portion projecting upwardly from the truncated edges of said inner wall, said feed portion having a solid upper end portion provided with an axial bore'and having a plurality of circumferentially spaced chambers which extend vertically therethrough; a hopper supported on said feed portion, an upper wall on said hopper, a shaft rotatably supported by said upper wall; said shaft projecting through said hopper and through the axial bore in said feed portion to a point below the bottom of said annular chamber; a solid plate fixed to said shaft directly below the discharge end of said feed portion; an annular grate at the bottom of said combustion chamber, said grate mounted on said plate; a second shaft telescoped over the first named shaft, said second shaft supported by the upper wall of said hopper; valve plates fixed to said second shaft, said plates arranged when rotated to alternately close the upper and lower ends of each of the chambers in said feed portion, a cam feed wheel fixed to the lower end of said second shaft, said cam feed wheel. positioned between the delivery end of said feed portion and said plate and means'to intermittently rotate said shafts in opposite directions.

12. In apparatusfor burning solid fuel, a suit able shell enclosing an annular combustion chamber, the inner wall of said shell having the lower end thereof terminating in a plane adjacent the bottom of said chamber, a tubular feed portion projectingupwardly from the lower edges of said inner wall; said feed portion having a solid upper end portionprovided with an axial bore and a plurality of circumferentially spaced chambers which extend vertically therethrough,

a hopper supported on said feed portion; an

upper wall on said hoppena shaft rotatably supported by said upper wall, said shaft projecting through said hopper and through the axial bore in'said feed portion to a point below the bottom of said annular chamber, a grate" at thebottom of said combustion chamber, said grate mounted on said shaft; a second shaft telescoped over the first named shaft, said second shaft supported by the upper wall of said hopper; valve plates fixed to said second shaft, said plates arranged when rotated to alternately close the upper and cated'end thereof directed downwardly and terminating in a plane adjacent the bottom of said chamber, a tubular feed portion projecting upwardly from the truncated edges of said inner.

wall, a hopper supported on said feed portion; an upper wall on said hopper, a space enclosing casing'secured to the upper wall of said hopper and extending downwardly around the hopper in V spaced relationthereto and .in spaced relation to wall of said hopper provided with an opening leading to the space between the hopper andsaid casing and a grate at the bottom of said chamber.

14. In a furnace having an annular comb-ustion chamber; a grate at the bottom of said chamber, said chamber having an inner wall in. the form of a hollow inverted truncated cone which extends downwardly to a plane adjacent said grate; a tubular extension projecting upwardly from the lower edge of said inner wall; said extension terminating at the upper end thereof'in a solid end portion; a hopper mountedon said solid portion, a plurality of openings forming circumferentially spaced chambers extending through said upper end portion, a rotatable valve plate on the upper side of said solid portion, said valve plate having an opening adapted to be successively brought into register with eachof said chambers tofill the chamber with fuel from said hopper and a like valve plate onthe lower side of said solid end portion to successively release the fuel from said chambers into said tubular extension and deposit the same on the 0611-, tral portion of said grate and means to force the fuel thus deposited outwardly on said grate.

15.1n a furnace walls forming an annular combustion chamber, a grate. at the bottom of said chamber; the inner wall of said furnace extending downwardly and terminating, in. close spaced relation to said grate, a feeding tube leading downwardly through the) cavity of said inner wall, means to intermittently feed solid fuel through said cavity to said grate, said means including a valve positioned above the lower end of said feeding tube, said valve provided with a plurality of chambers, means to successively fill each of said chambers with fuel and means to successively release the fuel from' each of said chambers. a

16. In a furnace of the character describedan outer wall, an upper, wall and an inner wall,

said walls partially enclosing a combustion chamcumferentially extending bulged area forminga channel on the inner side thereof, a lining on the inner side of said inner wall, said lining covering said channel to providean air space betweenthe inner wall and the lining, said inner wall having a circumferentially arranged series'of bores which extend therethrough and communicate withsaid air space and a tube communicating with the air outside said casing and leading to said airspace.

17. In an apparatus for burning solid -an outer wall, an upper wall and an inner wall connected to partially enclose an annular combustion chamber; a circular grate at the bottom ofsaid chamber; the inner wall of said chamber extending downwardly in close spaced relation to said grate; a hopper mounted within said inner wallfor feeding fuel to the central portion of said grate, an upper wall on said hopper, a tubular shaft rotatably supported by the upperwall of said hopper and a cam feeding wheel mounted on said shaft in a horizontal plane between the lower edge of said inner wall and said grate; a second shaft rotatably mounted in the first named shaft and projecting fromeach endithereof, said grate fixed to'the second named shaft and means to provide a relative rotary movement of said shafts.

, 18. In an apparatus for burningsolidfuel, .ar

suitable shell having inner and outer walls enclosing a combustion chamber, the inner wall of said shell projecting downwardly to a plane adjacent the bottom of said chamber, a feed portion projecting upwardly from the lower edge of said inner. wall, fuel supplying means operatively connected to said feed portion; said feed portion having a portion provided with a plurality of fuel chambers spaced around the center thereof and extending vertically therethrough; a shaft rotatably supported on said fuel supplying means, said shaft projecting through said feed portion, a valve plate fixed to close the lower ends of said fuel chambers, an opening in said valve plate, said opening adapted to be successively registered with said chambers when rotated with said shaft, a second shaft rotatably mounted within the first named shaft, a grate fixed to the second named shaft, means to impart an intermittent rotary movement to said first named shaft and means to impart an opposite rotary movement to the second named shaft.

19. In an apparatus for burning solid fuel, a shell enclosing an annular combustion chamber, a fuel feeding tube leading downwardly through the cavity of the inner wall of said shell, a fuel feeding structure operatively mounted on said tube, a tubular shaft rotatably mounted in said structure and leading downwardly through said fuel feeding tube, and extending from the upper side of said structure to a plane below said combustion chamber, and a grate forming the bottom of said combustion chamber, said grate mounted on the lower end of said shaft, the bore of said tubular shaft adapted to provide a draft passage leading from the top of said apparatus to the space below said grate.

20. In an apparatus for burning solid fuel, a shell enclosing an annular combustion chamber; a fuel feeding tube leading downwardly through the cavity of the inner wall of said shell, a fuel feeding structure operatively mounted on said fuel feeding tube, a tubular shaft leading downwardly through said structure and feeding tube and extending from the upper side of said structure to a plane below said combustion chamber; a grate forming the bottom of said combustion chamber, said grate mounted on the lower end of said shaft, the bore of said shaft adapted to provide a draft passage leading from the top of said apparatus to the space below said grate and adjustable means for controlling the flow of air through the bore of said shaft.

RUTHERFORD H. HUNTER.