US1457339A - Kiln and burner therefor - Google Patents

Description

June 5, 1923.

E. M. BASSLER KILN AND BURNER THEREFOR Filed March 22. 1920 Patented June 1923.

UNITED STATES- ame "Par-agar orrics. '7

EDWIN M. BASSLER, OF MILWAUKEE; WISCONSIN.

xnm AND BURNER THEREFOR.

Application filed. March 222, 1920. Serial No. 867,624.

/ To all whom it may concern Be it known that I, EDWIN M. BABSLER, a

citizen of the United States, and resident of Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented a new and useful Improvement in Kilns and Burners Therefor, of which the following-is a specification.

This invention relates to kilns and relates particularly to burners therefor, in which pulverized coal is used for fuel.

Heretofore, in accordance with the common standard practice, the pulverized coal is discharged into the kiln through a fuel supply pipe by means of an air blast of relatively high pressure and velocity, the.

pulverized coal being discharged into said uel supply pipe from a bin or other source of supply by means of a screw conveyor or other sultable means.

The volume and velocity of the air used for injecting the coal is varied to suit local conditions, the amount of air introduced being approximately only twenty-five per centof the volume of air necessary for complete combustion of the coal used. The additional air necessary to producecomplete combustion of the coal introduced into the kiln is supplied by induced stack draft and enters the kiln through various openings. This method of introducing what may be referred to as the secondary air supply is at best haphazard, being subgect to all changes of draft produced by atmospheric conditions, direction of the wind, etc., and cannot be controlled with any degree of accuracy. Such control as is possible is effected by regulation of the air blast in the fuel supply pipe and the stack draft, by means of valves or dampers.

The use of too much air tends to reduce the temperature in the kiln and requires the use of an excess of fuel to produce the desired temperature therein, while the use of too little air causes the generation of gases which are not consumed until after they reach the stack, where they combine fect oxidation, the reducing actionthereof afiecting the iron and sulphur content of the clinker, and impairing the'colonand the soundness of the finished product.

- The object of the present invention is to overcome the foregoing-"objectionable features by eliminating, so far as possible, all openings in the kilnthrough which leakage of air may be induced by the stack draft and provlding means for supplying air tow the kiln, which may be controlled and adjusted so as to supply a volume of air to the kiln proportioned to efiectcomplete combus ion of the fuel coal supplied thereto.

In accordance with what I now consider to be the referable embodiment of my invention, t e pulverized coal used for fuel pipe b means of a, current of air of relatively igh pressure. As previously stated, the volume of high pressure air thus admitted to the kiln is much less than is reis controlled by a valve or damper whereby the quantity of air admitted therethrough may be separately adjusted and regulated. Preferably, also, the pipe through which air is su plied to the header with which said air supp y plpes communicate, is also provided with a gate or valve by means of which the volume of air supplied to said header may be regulated to meet varyin conditions of atmosphere, direction and ve ocity of wind, e c.

My invention also comprises the various other features, combinationsof features and details of construction hereinafter described and claimed. a

In the accompanying drawings, in which my invention is fully illustrated,

Figure 1 is aside view of a kiln equipped with a burner of my invention.

Figure 2 is a sectional end view thereof on the line 2+2 of Fig. 1

Figure 3 is a sectional view of the discharge end of the fuel supply pipe'on the line 33 of Figure 2, on an enlarged scale.

Fi re 4 is a sectional view of the fuel supp y pipe on the line 4- 1 of Fig. 3;. and

Figure 5 is a sectional view of one of -is supplied to the kiln through a fuel supply I the secondary air supply pipes on the line of Fig 1.

In the accompanying drawings, I have shown my invention and improvements as applied in useto a usual form of cement kiln comprising a shell indicated at 1, which is rotatably mounted at a small angle to the horizontal, the inclination thereof being downwardly towards its discharge end; a closure 2 for the discharge end of the shell 1, said closure being stationary and being made of suitable refractory material, as firebrick or the like; a fuel supply pipe 3, through which pulverized coal is adapted to be delivered into the kiln by a current of air of sufficiently high pressure and velocity to form a vehicle for said pulverized coal; a

blower 4 adapted for supplying air under pressure to said fuel supply pipe; a bin 5 for containing the powdered coal to be used I as fuel; and a screw conveyor 6 connected to the lower end of the hopper shaped bottom of the bin 5, adapted to discharge the pulverized coal from said bin into the fuel supply pipe 3, said screw conveyor being driven from a suitable source of power, not shown, by a belt applied to a pulley 7 secured to the projecting end of the shaft of the conveyor screw, or other means.

All of the foregoing features are old and well known in the art, and, excepting as hereinafter particularly described, may be of any usual or approved construction and will readily be understood by persons familiar with the art without .a description thereof in detail.

As stated, the air entering the kiln through the fuel supply pipe 3 is only about twentyfive per cent of the total volume of air nec-.

essary for effecting complete combustion of the fuel supplied to the kiln, and to provide the additional air necessary to effect complete combustion of the fuel and for regulating the quantity of air as nearlyas practicable, to the exact amount necessary to produce complete combustion, I provide what may be referred to as a secondary air supply, preferably of relatively low pressure and velocity. As shown, the means for supplying such secondary air consists of a header 8 supported adjacent to the closure 2 of the kiln and connectedwith a blower by means of a pipe 9.

In what I now consider its preferable form, the header 8 forms a segment of an annular receptacle, and may be described in a general Way as substantially horse-shoe shaped. Air under pressure is adapted to be discharged from the header 8 into the rear or discharge end of the kiln by means of pipes 10, which are secured in the wall of said header and the outer ends of which extend into holes 11 formed in the closure 2 of the kiln. As shown, there'is a considerable number of the pipes 10 arranged in a valve or damper 12 which affords convenient means for regulating the effective size or area of the plpe opening and which, in use, is designed to be secured in fixed ad ustment by means of a set screw or other means.

The valves or dampers 12 in the pipes 10 are provided primarily for the purpose of proportioning the volume of secondary air to the volume of. high pressure ajir discharged into the kiln through. the fuelsupply pipe 3, and, in operation, their adjustment will be substantially permanent or will be changed onl at considerable intervals. The volume of air admitted to the kiln through the pipe 9 to meet varying conditions of atmosphere, wind, etc., is adapted to be controlled by a gate or valve indicated Preferable means for supplying high and low pressure air to the kiln consists of a compound blower, indicated at 4, the pipe 9 being connected to the discharge opening of the first or low pressure unit of said blower and the pipe 3 to the discharge opening of the second or high pressure unit therefore. may be purchased commercially or can be readily supplied by persons skilled in the art, and said fan is not, therefore, herein shown or described in detail.

If for any reason desired, my invention contemplates the use of separate blowers for supplying high and lower pressure air to the kiln.

It is found in practice that the pulverized fuel delivered into the fuel supply pipe-3 by the screw conveyor 6 has a tendency to settle and collect at the bottom of said fuel supply pipe adjacent to its discharge end, thereby choking said pipe and destroying the balance between the high pressure and the low pressure air. To overcome this objectionable feature, I provide for discharging jets of air upwardly through the bottom of the section of said pipe where said coal tends to. deposit, said air jets being preferably directed at an angle upwardly and towards the discharge end of said fuel supply pipe. Simple means for this purpose consists of a jacket 14: on the pipe 3, which is connected with said pipe 3 by a pipe 15, which communicates with said pipe 3 between the blower 4 and the point where the conveyor 6 discharges into said pipe. Also, to provide for directing the jets at an an angle upwardly and towards the discharge end of the pipe 3, the jacket 14 preferably comprises a plate 16 fitted to the outside of the pipe 3, said pipe 3 being cut away beneath said jacket. Said plate 16 is Fans suitable for the purpose fied in claim 1, in which the secondary air of such thickness, say one-quarter of an inch,

that jet orifices 17, inclined at a desired angle to give the air jets discharged there from a desired direction, may be formed therein.

The pipe 3 is controlled by. a "valve 18 positioned between the points at which the pipe 15 leading to the jacket 14 and the screw conveyor 6 communicate therewith, thereby providing not only for regulating the volume of air passing through said fuel supply pipe, but also providing for diverting a portion of air from the pipe 3 into the pipe 15 and thence into the jacket 14, where it is again discharged into the fuel supply pipe in the form of air jets in the manner described. Preferably, also, the pipe 15 is controlled by a valve 19.

Also, if desired, my invention contemplates the use of a lip or wing 20 on the inside of the pipe 3 for diverting air from said pipe into the pipe 15.

I claim:

1. The combination of a kiln anda burner therefor, said burner comprising a fuel supply pipe, means for creating a current of air therethroughforming a primary air supply, a header, pipes which connect said header with the interior of the kiln and are spaced radially from said fuel supply pipe, and means for supplying air under pressure to said header forming a secondary air suppl said secondary air supply being of relative ylow pressure and large volume as compared with the primary air supply, substantially as described.

2. A kiln and a burner therefor. as specisupply pipes discharge into the kiln adjacent to theshellthereof, substantially as described. A A

3. A kiln and a burner therefor as specified in claim 1,in-which the fuel supply pipe and the secondary-air supply pipes are arranged substantially centrally and adjacent to the shell of the kiln, respectively, substantially as described.

4. A kiln and a burner therefor as specified in claim 1, in which the secondary air I supply, pipes are arranged in series, the extreme pipes of :which are spaced a considerable distance above the bottom of the shell of the kiln, substantially as described.

5. A kiln and a burner therefor as specified in claim 1, comprising means for delivering pulverized fuel into the fuel supply pipe, and means for preventing the deposit of fuel therein,"comprising a jacket which encloses the under side of said fuel supply pipe, a wall separating said jacket and fuel supply pipe provided with jet openings, a pipe which connects said jacket with the fuel supply pipe between the means for supplying air under pressure to said fuel supply pipe and the point at which fuel is delivered into the same, and means for diverting a sufiicient volume of air from said fuel supply pipe into said jacket to create a differential pressure in said jacket greater than the pressure in the section of the fuel supply pipe which said jacket encloses, substantially as described.

6. A kiln and a burner therefor as specifled in claim 5, in which a valve is connected into the fuel supply pipe between the points where the pipe connecting said fuel supply pipe and jacket communicates with said fuel supply pipe and fuel is delivered thereto, substantially as described.

7.- A kilnand a burner therefor as specified in claim 6,. in which there'is a lip in the fuel supply pipe adapted to' divert air; therefrom into the pipe whichconnects said fuel supply pipe jacket, substantially as described.

In testimony that I claim the foregoing as my invention, I affix my signature this 12th dayof March, 1920.

EDWIN M. BASSLER.

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