US2127726A - Stoker - Google Patents

Description

Patented Aug. 23, 1938 UNITED STATES PATENT OFFICE STOKER John Goats, Wanwatosa, Wis. Application October 3, 1936, Serial No. 103,8801i 11 Claims. (01. 198-64) My present invention relates generally to improvements in the art of feeding pulverulent fuel into combustion chambers, and relates more specifically to improvements in stokers for delivering.

regulated quantities of coal or the like to furnaces or boilers.

Generally defined, an object of my present invention is to provide an improved stoker which is simple, compact and durable in construction, and

m which is moreover highly efllcient in use.

Many types of stokers have heretofore been proposed andplaced upon the market, but all of these prior devices are relatively objectionable either because of their unsightly appearance, or

II due to the inconvenience encountered in supplying fuel to the hopper, or on account of the inefiiciency of the mechanical feed structure, or because of the escaping dust and fumes. Since stokers are rapidly becoming more popular for 90 residential use, it is important that suchdevices present an attractive appearance and that they be readily accessible for the delivery of fuel thereto at least to the same extent as the furnace or boiler firing door was accessible. It is also 25 desirable that these mechanical stokers be dependable in operation, and foolproof against excessive damage in case the feed mechanism becomes obstructed by tramp iron or other abnormal objects which may frequently appear in low 30 grade fuel such as is ordinarily supplied to a stoker. It is moreover desirable to have the stoker bin and other casings effectively sealed against possible escape of gases and dust, and none of the prior commercial fuel stokers have 35 embodied all of these important and desirable features. i 7 It is therefore anmore specific object of .the present invention to provide an improved stoker assembly which obviates all of the objectionable 40 features or the prior devices of this type, and which is dependable in operation in that the fuel supply is automatically and positively delivered from the hopper to the grate.

5 Another specific object of my present invention is the provision of a stoker unit which is extremely attractive in appearance, and wherein the. fuel may be most conveniently supplied to a hopper which is adapted to be set for loading from the 5 rear of the unit or from either side thereof.

A further sp ific object of this invention is to provide an improved hopper and feed screw assemblage wherein the fuel is effectively delivered by gravity to the zone of action of the screw,

55 and the latter is adapted to most efiectively withdraw the descending fuel charge from the bottom of the hopper.

Still another specific object ofmy present invention is the provision of improved instrumentalities for positively preventing choking of the fuel feed ducts of a stoker, and for protecting the apparatus against excessive damage due to abnormal conditions of operation.

An additional specific object of the invention is to provide improved closures for a stoker supply. m bin or hopper, which while permitting ready access to all portions of the normally concealed storage space and feed mechanism, will also effectively guard against possible escape of gases, soot and dust.

My present invention also contemplates provision of an improved stoker unit which can be manufactured and sold at moderate cost, which may be quickly installed, and which is extremely economical in normal operation.

The above as well as other specific objects and advantages of this invention will be apparent from the following detailed description.

A clear conception of embodiments of the several features constituting the present invention, and of the mode of constructing and of operating stoker units embodying these features, may be had by referring to the drawing accompanying and forming a part of this specification, wherein like reference characters designate the same or similar parts in the various views:

Fig. 1 is a combined rear and side perspective view of a complete stoker unit especially adapted for industrial or residential service;

Fig. 2 is an enlarged central vertical l'ongitudinal section through the fuel supply structure, showing the improvedhopperpositioned for loading from the rear; t

Fig. 3 is a similarly enlarged central vertical transverse section through the lower portion of 40 the improved fuel supply assemblage; and

Fig. 4 is a somewhat diagrammatic top view of thehopper assemblage, showing the hopper in solid lines positioned for rear loading, and in dotand-dash lines positioned for alternative side loading.

While my invention has been illustrated and described herein as being specifically applied to a relatively small stoker unit for coal especially adapted for domestic service, it is not the intent to thereby unnecessarily restrict the scope, since some of the improved features may obviously be more generally applied.

Referring especially to Fig. 1 of the drawing,

the improved stoker unit shown therein comprises in general a grate assemblage 8 which is normally disposed beneath the combustion chamber of a furnace or boiler; a fan or blower Ill rotatable by means of an electric motor 9 to deliver air to the combustion chamber through the grate assembly 8; a hopper II for receiving the fuel supply through a door l2 and having an upwardly open cup-shaped supporting base IS; a normally concealed feed screw H for delivering fuel forwardly from the hopper i I to the grate assembly through a tubular casing I5; and a gear box IE forming a housing for transmission gearing adapted to transmit rotary motion from the motor 9 to the fuel feed screw H in a well known manner.

The hopper H which is preferably formed of sheet metal, is of improved construction as shown in Figs. 2, 3 and 4, and comprises a downwardly directed substantially upright portion I I, the lower end of which is disposed within and is in open communication with the interior of the cupshaped base l3; and an upwardly laterally directed and curved portion i8 of gradually diminishing cross sectional area terminating in a fuel supply opening disposed beyond the adjacent side wall of the hopper and with which the door I! ooacts. The lower portion of this hopper H is of equilateral polygonal cross-sectional shape, substantially square as shown in Fig. 4, and the confining wall for the lower hopper end is of like shape so that the hopper l I may be interchangeably positioned with its upper inlet opening either rearwardly accessible as shown in solid lines in 8. 4, or accessible from either side of the stoker as indicated in dot-and-dash lines. When the hopper II has been applied to the base lit in the desired position, it may be riveted, welded or bolted to the base so as to rigidly interconnect these parts.

The rectangular peripheral frame is of the lateral upper inlet opening, is preferably located outwardly beyond the adjacent hopper side wall and lies in a plane which is slightly inclined toward the hopper axis as shown in Figs. 1 and 2, and the fuel supply opening is preferably disposed above the floor line at a height substantially equal to that of a standard furnace or boiler firing, open- 'ing. The inlet closure door I 2 is swingably suspended by means of hinges i9 from one side of the frame l9 and has a continuous seal formed of flexible material such as rubber, which is adapted to be forced into sealing contact with the frame ridge 2| with the aid of a latch 22, see Fig. 2. The latch 22 and the door l2 are manipulable by means of a handle 23, and it will be noted that when the door I! is located rearwardly over the motor 0 as illustrated in Fig. 1, the exposed portion of the stoker assemblage has an attractive and compact streamlined appearance.

The improved cup-shaped hopper base l3 may be formed in any suitable manner and has oppositely inclined side walls 24 connected at their lower ends with a flat bottom which extends beneath the fuel feed screw it as shown in Figs. 2 and 3, thereby exposing both the top and both sides of the screw I to the fuel descending from the hopper l I upon the base. One or both of the inclined side walls 24 may be provided with an opening which is normally closed by means of a readily removable closure plate 25 coacting with guide lugs 26 as shown in Figs. 1 and 3, and the base I 3 may also be provided with suitable supports 21. The tubular casing l5 within which the 1 screw II is rotatable, may be formed in sections one of which is formed integral with the base It as indicated in Figs. 2 and 4 and has an upper opening therein extending from the forward lower wall of the hopper ll along the top of the screw M. This upper opening is normally sealed by a special closure plate 28 shown in detail in Figs. 2 and 4, this plate having a rearwardly extending portion 29 projecting along the screw beneath the hopper wall and normally being held in position by cap screws 30. The rear end of the plate 28 has its edge disposed at an angle conforming substantially with the pitch of the screw l4, and the medial lower face 3| of the plate has a sloping shape so that when the cap screws 30 are removed or broken, the plate 29 will be automatically forced forwardly by the screw I 4 and will be simultaneously lifted out of the opening to expose the adjacent portion of the feed screw.

While the hopper H is formed downwardly diverging or enlarging in cross section in order to prevent bridging of the fuel over the conveying screw I4, I may additionally provide automatic bridging preventing mechanism such as disclosed in detail in Figs. 2 and 3. This improved mechanism comprises a central disk or wheel 32 supported for free rotation within the center of the lower hopper portion I"! by a horizontal shaft 33 which spans the hopper. The disk wheel 32 has a peripheral series of abutments 34 which are successively engageable with the constantly advancing forward face of the feed screw It, to continuously revolve the wheel; and also has laterally projecting cutters or spurs 35 extending in opposite directions therefrom. It will be apparent that as the screw I4 is rotated, the spurs 35 will be revolved within the lower hopper portion l1 and will positively prevent bridging of fuel within the hopper I I over the feed screw H. The fuel feed screw i4 is of well known construction, preferably having different pitch as it approaches the grate assembly 8, and is adapted to be driven at variable speeds through speed change gearing of usual and well known construction confined within the gear box l6.

During normal operation of the improved stoker unit, the motor 9 is operable to actuate the blower i0 and to thereby supply air to the grate assembly 8, and is simultaneously functioning to rotate the fuel feed screw l4, whenever the motor is placed in operation. The hopper Ii may be charged with bulk 'fuel when the door I 2 is opened, and the lateral inlet opening of the hopper ll obviously enables original disposition of this door l2 so as to permit most convenient loading of the hopper from the fuel supply bin. The fuel admitted to the hopper ll descends toward the cup-shaped base II and settles or slides along the inclined side walls 24 toward the exposed sides of the rotating screw ll. As the screw it rotates, the disk wheel 32 is simultaneously revolved about the axis of its supporting shaft 33, thereby causing the spurs 35 to travel through the mass of fuel within the lower portion of the hopper II and to prevent packing or bridging thereof. The fuel bed is thus caused to move downwardly and inwardly toward the screw ll both from the top and sides, and this action enables the feed screw to constantly withdraw a full charge of fuel from the hopper so long as the latter is properly supplied. This operation of the fuel feeder is obviously entirely automatic and requires no attention except the maintenance of a sufficient supply of fuel to the hopper.

In case the admitted fuel contains a large piece of tramp iron or some other hard object which cannot be broken and fed by the screw H, the object might damage the screw or casing if no prounit may be manufactured, installed and operated ing at one side thereof vision were made to prevent such damage. Such an object will be fed by the screw ll toward the conveyor tube or casing I5, and upon striking the inwardly projecting-portion 29 ofthe plate 28;will ultimately produce sufficient pressure to break the cap screws 30. After these clamping screws are broken, the plate 28 will be pushed along the casing l and will be lifted clear of the adjacent opening, by the lower inclined surface 3|. The

obstructive hard object will subsequently escape through the upper opening in the casing l5, and the closure plate 28 may thereafter be reapplied to the opening with new cap screws 30. I

The interiors of the hopper II and screw casing I! besides being freely accessible through the door I! and past the plate 28, are also accessible upon removal ofthe side closure plate 25. All portions of the fuelvfeed assemblage are thus conveniently accessible for inspection and repairs, and the mechanism is effectively protected against serious damage. Since the fuel supply door I2 is disposed similar to an ordinary firing door, the hopper H may be readily loaded, and the formation of the hopper with a symmetrical polygonal lower end which is interchangeably cooperable with the base l3 in different angular positions, permits location of the door at the most convenient place of access.

From the foregoing description it will be apparent that the present invention provides a stoker assembly which is highly dependable and automatic in operation when properly supplied with fuel, and which may be conveniently loaded. The unit besides being readily accessible, is compact and very attractive in appearance, and is also extremely durable in construction. The fuel is most eifectivcly delivered to the feed screw by the inclined base walls and stirring device cooperating with the hopper formation, thus insuring most eifective delivery of fuel to the grate. The apparatus is moreover protected against serious damage, and is also well guarded against possible escape of gases, soot and dust. The improved stoker at moderate cost and has proven highly efficient in actual commercial operation.

It should be understood that it is not desired to limit the invention to the exact details of construction, and to the precise mode of operation herein shown and described, for various modifications within the scope of the appended claims may occur to persons skilled in the art.

I claim:-

1. In a stoker, feed mechanism for delivering fuel to a place of utilization, a hopper for delivering fuel to said feed mechanism and having '9. lat-.

erally directed upper wall and a fuel inlet openmeans for interchangeably positioning said hopper to permit injection of fuel through said inlet opening either longitudinally or laterally of the direction of fuel delivery from said hopper by said mechanism.

2. In a stoker, a feed screw for delivering fuel to a place of utilization, a hopper having a downwardly extending lower portion for depositing fuel into the zone of action of said screw and alsohaving a laterally directed upper wall and a fuel inlet opening near the top and at one side thereof beneath said wallfand means for interchangeably supporting said hopper to permit injection of fuel throughsaid opening indifferent directions.

3. In a stoker, fuel feed mechanism, a hopper for delivering'fuel to said mechanism and comprising a downwardly directed lower portion and beneath said wall, .and

a laterally curved upper portion terminating in a.

substantially horizontally directed inlet opening at the upper end and at one sideof the hopper, and a laterally opening closure door for said inlet opening.

4. In a stoker, fuel feed mechanism, a hopper for delivering fuel to saidmechanism and comprising a downwardly directed lower portion and a laterally curved upper portion terminating in a substantially horizontally directed inlet opening at the upper. end thereof,. a laterally opening closure door for said inlet opening, and a support for said hopper formed to permit interchangeable positioning of said door in different locations.

5. In a stoker, a fuel feed screw, a base having fuel supporting surfaces inclined at slight angles laterally toward and a substantially horizontal surface connecting the adjacent ends of said inclined surfaces and extending beneath said screw, a hopper supported by said base and having a downwardly directed lower portion and a laterally directed converging upper portion provided at itsend with a laterally directed side inlet opening, and a laterally swingable closure door for said opening.

6. In a stoker, a fuel feed screw, a base having fuel supporting surfaces inclined at slight angles laterally toward and extending horizontally beneath said screw, ,a hopper supported by said base and having a downwardly directed lower portion and a laterally directed converging upper portion provided at its end with a laterally directed side inlet opening, a laterally swingable closure door for said opening, and means for securing said lower hopper portion to said base in different fixed positions.

'7. In a stoker, a fuel feed screw, a base having:

fuel supporting surfaces inclined at slight angles laterally toward and extending horizontally beneath said screw, a hopper supported by said base and having a downwardly directed lower portion and a laterally directed converging upper portion provided at its end beyond the side of the hopper with a laterally directed side inlet opening, and a laterally swingable closure door for said opening, the supporting end of said lower hopper portion and the hopper receiving portion of said base having equilaterally polygonal similar transverse cross-sections.

8. In astoker, a fuel feed screw, a shallow wide base extending horizontally beneath said screw and laterally beyond the opposite sides thereof, the top and both entire sides of said screw being open to the interior of said base, and

a hopper having a vertically directed lower portion in open communication with said base interior and also having an upper laterally curved portion prpvided'at its end with a laterally directed side inlet opening located outwardly beyond the adjacent side wall of said vertical portion.

9. In a stoker, a fuel feeder, a sheet metal hopper having a downwardly directed lower portion for directing fuel in bulk toward said feeder and also havingv an integral laterally directed upper inlet portion provided with a substantially horizontally directed side inlet opening having an inclined bounding edge, and a laterally swingable door having a flexible continuous seal cooperable with said edge.

10. In a stoker, a fuel feeder, a hopper having a substantially vertical lower portion for directing fuel by gravity toward said feeder and also having a laterally directed upper inlet portion provided with a substantiallyhorizontally directed side inlet openim having substantially upright side bounding edges connected by horizontal upper and lower-bounding edges, the upper and lower bounding walls of said hopper at said opening being gradually downwardly curved receding from the opening, and a laterally swingable door having a continuous flexible sealing strip cooperable with said opening edges.

11. Ina stoker, a. fuel feeder, a. hopper having an upright lower portion for directing fuel toward said feeder and also having a laterally directed upper portion provided with curved upper and lower bounding walls merging into said lower portion and with a substantially horizontally directed inlet opening at the ends of said walls beyond a side of said lower portion, and a. laterally swingable door for sealing said inlet opening.

JOHN GOE'IZ.

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