US1564542A - Method of maintaining combustion in furnaces - Google Patents

Description

Dec. 8, 1925. 1,564,542

w. M. DUNCAN METHOD OF MAINTAINING COMBUSTION IN FURNACES Filed Jan. 17. 1924 4 Sheets-Sheet 1 HOT WATER #07 AIR AIR com WATER A 7' TOR/YE y:

Dec. 8 1925- 1,564,542

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UNlTED STATE VIILLIAIii Ili. DUNCAN, OE ALTON, ILLINGIfi METHOD OF MAINTAINING COMBUSTION IN FURNACES.

Application filed January 17, 1924. Serial No. 686,?63.

To all whom 2'0 may concern.-

Be it known that I, Wnmnmr M. DUNCAN, a citizen of the United States of An'1erica, a resident. of Alton, in the county of lrfadison, State of Illinois, have invented certain new and useful Improvements in Methods of iiiiaintaining Combustion in Furnaces, of which the following is a full, clear, and exact description, reference being had to the accompanying drawing, fori'ning a part of this specification.

This invention relates to improvements in methods of maintaining combustion in furnaces, and the new method is preferably carried out in a furnace wherein the fuel and ashes, or other residual matter, are confined by the walls of the con'lbustiou chamher.

One of the objects is to provide a method wherein ashes, or the like, may be continually fed away from the confined fuel. Another object is to continually add fresh fuel to the bed of fuel confined by the combustion chamber.

A. further object is to produce a draft for efficient combustion in a furnace of this kind.

To illustrate the invention 1 have shown a cylindrical combustion chamber surrounding and confining a bed of ashes with the fuel supported thereon. Instead of using a grate for the admission of draft to the fuel, the bed of ashes seals the bottom of the combustion chamber, and a forced draft may be admitted between the ashes and the fuel. Additional draft is preferably admitted above the bed of fuel. While the ash seal is maintained at the bottom of the coml'mstion chamber, ashes may be continually fed away from the bottom of the seal, and fresh fuel may be continually fed onto the top of the confined fuel bed. The coinbustion chamber may have a hollow wall wherein water is confined to be heated and at the same time prevent overheating of the wall. The draft is preferably heated by passing through a portion of this hollow wall.

This method has many advantages not present in the ordinary mechanical stoker consisting of an endless chain grate on which fuel and ashes are conveyed from the front to the rear of a combustion chamber. The new method can be carried out in an inexpensive furnace having a relatively high fuel capacity. The fuel can be rapidly consumed by regulating the forced drafts above the ash seal, so as to generate a very intense heat in a small and inexpensive furnace. The desired conditions'can be easily obtained by regulating the admission of fuel, the discharge of ashes, and the admission of draft. The ash discharge can be controlled independently of the mechanical stoker whereby the fuel is admitted, and the body of ashes does not interfere with the admission of draft which can be regulated independently of the fuel and ashes.

The new method can be followed in the heating of boilers and various other apparatus, or in the manufacture of gas or coke.

Fig. I is a side elevation, partly in section illustrating a furnace adapted for use in carrying out the new method.

Fig. II. is an enlarged vertical section of the furnace.

Fig. III is a horizontal section on the line IIIIII in Fig. II.

Fig. 1V is a section on the line IVTV in Fig. II.

The cylindrical combustion chamber herein shown comprises hollow lower sections 1, 2 and 3, hollow intermediate sections 4.: made of refractory material resting upon the lower sections, and upper sections 5 and 6 supported on the sections 4t. The hot gases may pass from the top of the combustion chamber to a boiler (Fig. I) comprising a shell 7, headers 8 and tubes 9 connecting the headers.

In Fig. 11, A designates a bed of fuel confined by the surrounding walls of the combustion chamber and resting upon a bed of ashes B, or other residual matter, which is likewise confined by the combustion chamber. This chamber is open at the bottom and the residual matter rests upon a feeder 9, preferably an endless conveyor located below the combustion chamber and mounted on sprocket wheels 10. One side of the combustion chamber is provided with an outlet at 11 (Fig. II) for the discharge of ashes, and the like, and the conveyor 9 travels across the open bottom of the combustion chamber in the direction indicated by arrows to continually feed the ashes through said outlet and thence to a pit 12.

The upper portion of the combustion chamber is provided with a peripheral fuel inlet between the sections 5 and 6, this inlet being formed around the combustion chamher to receive fuel from hoppers 13. Each hopper has an opening 14 (Fig. II) at the bottom for the discharge of fuel. Plungers 15 reciprocate in the fuel inlet to force the fuel from the openings 14 to the interior of the combustion chamber where it falls onto the bed of burning fuel A. The incoming fuel is thus distributed around the combustion chamber to form a substantially uni form fuel bed on the ashes B.

The means for reciprocating the plungers 14 comprises eccentrics 16 fixed to shafts 17, and arms 18 surrounding the eccentrics and pivoted at 19 to the respective plunge-rs.

The shafts 17 are geared together at 20, as shown in Fi III, and one of said shafts is provided with a drive pulley 21 which may be operated continuously. The mechanical stoker is thus driven to continually deliver coal to the bed of burning fuel, and the ash conveyor 9 is driven to continually carry away ashes from the confined fuel.

Draft is admitted through an annular passageway 22 (Fig. II) between the ash seal B and the bed of burning fuel.

23 designates an annular chamber surrounding the combustion chamber and communicating with the passageway 22, as shown most clearly in Fi II, and 24 is a blower whereby air'is forced through said chamber 23. The upper sections 5 and 6 may be used to preheat this air. 25 designates an inlet pipe (Figs. II and III) through which cold air is admitted to the upper section of the hollow wall, and 26 is an air conductor leading from the upper section to the sect-ion 5. The air heated in these sections is transmitted through a conductor 27 to the blower 24. Additional air may be admitted through pipes 28 extending through the combustion chamber at points above the fuel bed A.

The hollow wall of the combustion chamber can be used as a boiler, or as a means for heating the water passing to the boiler above the furnace. 29 designates a pipe through which cold water is admitted to the hollow bottom section 1, and 30 designates pipe connections whereby the water is conducted from the bottom section to the section 2 and thence to the section 3, the latter being provided with a discharge pipe 31 (Figs. I and II) leading to the shell 7 of the boiler.

Instead of being made of a single annular member, each of the hollow sections 1, 2, 3, 5 and 6 may consist of several hollow arcuate members having their ends connected by means of nipples 32, as shown in Fig. IV, to provide communication between the adjoining arcuate members.

I claim:

1. The method which comprises burning a bed of fuel on a bed of ashes, moving the lower portion of said bed of ashes away from the upper portion thereof, confining the fuel bed and maintaining an open space for combustion above the surface of the burning fuel, feeding fresh fuel into said open combustion space and distributing it over the surface of the burning fuel at the bottom of said space, and introducing air into the burning fuel.

2. The method which comprises burning a bed of fuel on a bed of ashes, moving the lower portion of said bed of ashes away from the upper portion thereof, confining the fuel bed and maintaining an open space for combustion above the surface of the burning fuel, feeding fresh fuel into said open combustion space and distributing it over the surface of the burning fuel at the bottom of said space, introducing air into said bed of fuel, and introducing air into said open combustion space above the surface of the bed of fuel.

3. The method which comprises sealing the bottom of a combustion chamber with a bed of ashes, burning a bed of fuel on the bed of ashes, maintaining an open space for combustion immediately above the fuel bed, continually dropping fresh fuel into said open space so as to distribute it over the surface of the burning fuel at the bottom of said space, introducing air between the burning fuel and the seal formed by the bed of ashes, introducing air into the open combustion-space above the fuel bed, and contin ually feeding the lower portion of the bed of. ashes away from the upper portion thereof, so as to remove the ashes and at the same time maintain the ash seal.

4. The method which comprises sealing the bottom of a combustion chamber with a bed of ashes, burning a bed of fuel on the bed of ashes, maintaining an open space for combustion immediately above the fuel bed, continually dropping fresh fuel into said open space so as to distribute it over the surface of the burning fuel at the bottom of said space, forcing air into the bed of burning fuel, introducing air into the open conibustion space over the surface of said bed, and conveying ashes away from the bottom of said bed of ashes.

In testimony that I claim the foregoing I hereunto affix my signature.

WILLIAM M. DUNCAN.

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