US1532647A - Method of and apparatus for preparing, feeding, and burning pulverized fuel - Google Patents

Description

L. H. BERGMAN METHOD OF AND APPARATUS FOR PREPARING, FEEDING, AND BURNING PULVERIZED FUEL April 1925.

Filed AprQl 14 1924s a in the claims.

Patented Apr. 7, 1925.

UNITED STATES PATENT OFFICE.

LABS H. BERG-MAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO RAYMOND BROS. ENGINEER- ING CO., OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

METHOD OF AND APPARATUS FOR PREPARING, FEEDING, AND BURNING PULVER- IZED FUEL.

Application filed April 14, 1924. Serial No. 706,415.

To all whom it may concern:

Be it known that I, LABS H. BERGMAN, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Methods of and Apparatus for Preparing, Feeding, and Burning Pulverized Fuel, of which the following is a specification.

My invention relates to a new and improved method of and apparatus for preparing, feeding and burning pulverized fuel, and ithas for its object the improvement of the method and apparatus now in use. It is one of the principal objects of my invention to provide new and improved methods and apparatus whereby the coal or other fuel may be dried to a suitable extent while passing through the pulverizing mill and may be delivered to the furnace in such a condition that it will be completely consumed inv the combustion chamber of the furnace so" as to utilize fully the heat element of the fuel. To this end, it is the object of my invention to provide an arrangement of parts by which hot gases from the flue, preferably with the addition of air, shall be used for floating the pulverized particles from the pulverizing mill in lieu of the use of atmospheric air alone for this purpose.

The preferred means by which I have accomplished my objects are illustratedin the drawing and are hereinafter specifically described- That which I believe to be new and desire to cover by Letters Patent is set forth The drawing illustrates a mill connected up for feeding directly .to a furnace, with means for supplying the flue ases to the .mill, all shown more or less diagrammati- Cally. a

I ed therein, and

In the drawing, 10 indicates a furnace with a boiler 11 of any suitable type mountprovided with a flue 12 in an desired position with respect to the boiler 11 and the firebox of the furnace.

' In the drawing, I have indicated a mill of the impactior beater t e, but it will be understood that I do not esire to limit myself to this particular form of mill, except)- so far as such specific form may be claimed. In the construction illustrated, coal or other fuel to be pulverized is fed by any suitable means to a hopper 13 from which it is fed by feeding means 14 of any suitable type into the beater chamber 154 An air inlet 16 opens into the mill on the feed side of the chamber 15, the air inlet being provided with a damper 17. Within the beater chamher 15 are mounted a plurality of heaters 18 of any suitable type adapted to be operated by a shaft 19 passing through the beater chamber and driven by a motor 20. In the construction shown, the shaft 19 is supported by bearings 21, the beaters 18 being mounted upon and supported by the shaft 19. In the construction shown, the feeding device 14 is also driven from the shaft 19 by suitable connecting means of any approved type which it is believed to be unnecessary to describe in detail herein. The mill as illustrated comprises a conical extension 22 at the delivery side of the chamber 15, a beating and regulating device 23 being mounted upon the shaft 19 within the extension 22, as is usual in the mill of this type. The conical extension 22 communicates at its delivery end with a fan chamber 24, within which is mounted a fan 25 of any approved type. The fan chamber 24 is connected by a conduit 26'With a burner 27 opening into the firebox of the furnace 10.

It has been found in practice, in the use of a mill of this type, that under certain circumstances it is difficult to burn pulverized coal of a high moisture content.

The presence of the moisture within the firebox of the furnace is not itself a disadvantage, -and does not serve to prevent the full and complete consumption of the pulverized fuel, except in the case where such moisture is contained in the particles of the fuel. On the contrary, under certain conditions the presence of the moisture within the combustion chamber of the furnace is a distinct advantage, inasmuch as it has a tendency to assist in preventing the formation of slag. p

For the purpoe of separating the molsture from the particles of the pulverized coal, or

other fuel,,but without any attempt to remove the moisturefrom the stream of fuel as it is fed to the furnace, I have provided a connection between the flueportion of the furnace and the pulverizing mill for causing a current of hot flue gases'to flow from the fine to the beater chamber of the mill. This connection in the construction shown is in the form of a conduit 28 connected at one end with the flue 12 of the furnace and at the other end with the air inlet 16 of the mill, a damper 29 being provided in the conduit 28 for controlling the amount of gas permitted to enter therethrough.

As will be readily understood, in the use of the mechanism asillustrated, by closing the damper 17 completely" and opening the damper 29, the flue gases may be utilized alone for the flotation of the pulverized particles of fuel intothefurnace 10. In such case, it would be necessary that the air necessary for combustion be admitted to the furnace from some other source. It will be understood also that by .closing the damper 29 completely and opening the damper 17, the apparatus can be used without the admission of any flue gases, the fuel being carried to the furnace *by the air alone. In practice, the dampers 17 and 29 can be regulated with respect to each other for Varying in any desired way the proportion of air and hot flue gases, depending upon the construction of the furnace, the moisture content of the coal or other fuel as delivered to the hopper 13, and upon other conditions in any particular case. In the preferred operation of the furnace, a sufficient supply of hot flue gases is to be admitted through the pipe 28 for attaining the desired drying effect upon the fuel during its movement through the pulv'erizing mill and through the conduit 26.

In some instances, I have found that by the. use of a suitable supply of hot flue gases leaving the flue at a temperature of about 500 degrees Fahrenheit the moisture content of coal has been reduced from about fourteen percent to three or four percent, the fuel being changed from a cond1tion.in

which it was difficult to burn to a condition in which it burned readilyand was completely consumed Within the combustion chamber of the furnace.

It will be understood that while I prefer to employ the combination of par-ts as illus trated in the drawing, I do not desire to limit myself to the use of this particular arrangement and construction, except so far as the same is specifically rclaimed, since it is evident that changes might well be made in the arrangement and constructioriwithoutdeparting from the spirit of my invention.

I claim: i

1. The method of preparing, feeding and burning fuel, which comprises feeding the fuel to a puiverizing mill, causing a current of hot gases from the flue of the furnace to pass through the mill, admi the hot gases to the mill, controlling the amount of air admitted in relation to the amount of hot gases, and feeding the fuel tting air with by flotation on the current of air and gases from the mill to the furnace. i

2. The method of preparing,'feeding and burning fuel, which comprises feeding the fuel to a pulverizing mill, drying the particles of fuel during the movement through the mill by the introduction into the mill of hot gases from the flue portion pf the furnace, admitting air with the hot gases to the mill, controlling the amount of air admitted in relation to the amount of hot gases, and feeding the fuel to the furnace with the air, the partially cooled gases, and the moisture liberated from the particles of the fuel.

3. An apparatus for preparing, feeding and burning fuel, comprising a furnace, a pulverizing chamber, means for feeding fuel to said chamber, adjustable means for admitting air to said chamber, and means for causing a draft of'hot flue gases from the furnace to mix with the air and flow through with the air and flow through the chamber for carrying the puh'erized fuel, into the furnace, and means for controlling the amount of air with relation to the amount of hot gases in said current.

5. An apparatus for preparing, feeding and burning fuel, comprising a furnace, a pulverizing chamber, means for feeding fuel to the chamber, means for admitting air and hot gases to the chamber comprising an air inlet, and a conduit leading from the flue portion of the furnace, a damper in the air inlet, a damper in the conduit, a conduit connecting the chamber withthe fire box of the furnace, and means for causing a current of-air and hot gases to flow through the chamber and the latter conduit for carrying the pulverized fuel to the furnace.

6. An apparatus for preparing, feeding and burning fuel, comprising a furnace, a pulverizing chamber, means for feeding fuel to the chamber, means for admitting air and hot gases to the chamber comprising an air inlet, and a conduit leading from the flue portion of the furnace, a conduit connecting the chamber with the fire box of the furnace, means for causing a current of air and air inlet and in the first mentioned' conduit for regulating the relative proportions of the air and hot gases admitted to the chamber.

LABS H. BERGMAN.

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