US1542945A - Fluent pulverized fuel - Google Patents

Description

Patented June 23,' 1925.

UNITED STATES PATENTOFFICE.

ALONZO G. KINYON, OF ALLENTOWN, PENNSYLVANIA, ASSIGNOR TO FULLER-LE- HIGH COMPANY, A CORPORATION OF PENNSYLVANIA..

FLUENT PULVERIZD FUEL.

Application-"med*November 23, 1920. Serial No. 426,016.

To all whom t may concem;

Be it known that I, ALONZO G. KINYON, a citizen of the,l United States, residing at Allentown, in the county of Lehigh, State of Pennsylvania, have invented certain new and useful Improvements in Fluent Pulverized Fuel; and I do hereby declare the following to be a full,` clear, and exact description of the invent-ion, vsuch as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to a new fuel consisting primarily of coal in a state of fine sub-division and a relatively small amount of air intimately mixed therewith. This novel fuel is distinctive in that it is sluggishly fluent and in that va mass of the fuel at rest in a container will settle gradually, giving up its air content to the surrounding atmosphere slowly. Such a fuel is of great value by reason of the ease, simplicity, and economy with which it may be coni veyed from a supply point to one or more points of use; furthermore, under certain conditions of use, the presence of the air in the fuel and its intimate mixture with the fuelparticles may be utilized to advantage,

in effecting quick and complete combustion ofthe. fuel.

Such a fuel is produced by 'injecting air' under pressure into a body of pulverized l coal under suchv conditions that the air becomes finely i sub-divided and intimately mixed with the coal particles. The total volume of the air so injected into the pulverized coal may be several times the volume of the coal; experience indicates that the injection of six or eight units of volume of air to each unit of volume of pul' verized coal produces very ood results. vThe fuel thus produced is in a s uggishly fluent, or semi-fluid state, so that itofers relatively little frictional resistance to flow 1n a conduit and therefore maybe made to flow through a long conduit by the appli-V cation of mechanical pressure on the matcrial at one end of the conduit. The presence of the air which is entrapped under pressure within the interstices of the mass, reduces the normal frictionbetween the particles to such a degree that a mass of the material when unconned possesses substantially no angle of repose and will flow freely over any surface upon which it may be poured. Ifthe fuel be poured into a barrel or other container and the barrel be tilted slightly on its edge, back and-forth. The end of a bar of 'a piece of woodmay be inserted into the fuel 1n the container and moved back and forth 'therein with but little resistance to its movement on account of the fluid character of the fuel. In this state of rest of the fuel in the barrel, there would be slow settling of the fuel as the air particles in the fuel rose to and escaped from the surface of the fuel, but this settling is not rapid enough to have `any substantial detrimental effect in the utilization of the fuel, particularly as it occurs only when the fuel is exposed to atmospheric pressure.

the fuel will surge By reason of this semi-fluid condition and the fact that a body Aof the new fuel at rest will settle but slowly, the new fuel is sharply distinguished ,from those 'mixtures of air and pulverized coal which have been commonly employed heretofore in which the volume of the air is many times the volume of coal and the coal particles are in sus-` pension in the air. Such kmixtures are usually formed to permitof conveying the coal bymeans of a moving current of air, and

when such mixtures are brought to rest, the coal particles drop by gravity practically immediately and collect in a mass at the bottom of the receptacle intowhich the mixture is brought vto rest.

\A mixture in which' the particles of coal are held in suspension in a relatively large volume of air is explosive in its nature, and care must be exercisd` that it is not accidentally ignited. The present fuel is not an explosive mixture and may be handled with safety under all conditions. Furthermore, since .the fuel contains a relatively small amount of entrapped air as compared with the amount present in mixtures in which the coal particles are conveyed in suspension, it may be discharged from distributing conduits directly without requiringthe use of apparatus such as cyclone'separators to remove the air. The fuel is also free from dust and is therefore clean to handleexcept for the adherence of particles of material upon surfaces with which they may come in Contact. p

The new fuel, by reason of its sluggishly fluent condition, can be transported from place to place with simple apparatus, and

-cident to obtaining quick and complete combustion. When pulverized coal is fed into a furnace and ignited, it is essential to produce an intimate mixture of the coal particles and the air needed to supply the oxygen for combustion. Under some conditions the new fuel may be utilized in such a way that this operation is simplied by the fact that the fuel itself carries a substantial amount of air in intimate admiXture with the coal particles.

As an illustration of the manner'in which 4the new fuel may be produced, there is i shown in the accompanying drawing in sectional elevation a preferred form of apparatus for this purpose. This apparatus includes a cylindrical Vcasing 10 provided at one end with a supporting foot 11 and connected at the other end to a standard 12,

having a cylindrical bore of the same diameter as the interior of the casing. Abovethe bore is a hopper 13 of any suitable shape and capacity provided with a damper or other form of controlling device 14 by which the discharge of pulverizedcoal from the hopper may be regulated. Extending through the casing 10 and the bore of the standard 12 is a screw conveyor 15, the shaft 16 of which projects through a suitable bushing 17 which also serves as a closure for the outer end of the bore. The shaft is continued through a bearing 18 which constitutes the main support for the shaft, and its end is connected to an electric motor 19 or other source of power, thel connection preferably being in the form of a flexible coupling 20 of any suitable type.

The pitch of the screw conveyor 15 may be made to decrease from the end at .which coal is supplied to the end from which it is discharged, the purpose of this arrangement being to compress the pulverized coal as it approaches the discharge end of the conveyor, so that the coal will act as a seal to prevent the air that is introduced as .the coal leaves thc conveyor' from flowing through the casing toward the hopper and aerating the coalbefore it has been discharged from the conveyor. Y C' For the purpose of introducing air into the coal, there is attached at the forward end of casing 10 an annular casting 21, thel lower lportion of which is provided with a semi-circular passage 22 substantially conposite points. One

centric with the bore of the casting and hav* ing its ends brought out to the exterior of the casting, preferably at diametrically opend of the passage may be closed by a plug, while into the other end there is screwedone end of a pipe 23 leading to a tank 24 in which the air that is to be injected into the coal maybe compressed b v a suitable compressor 25 which may be driven by the motor 19 that drives the screw conveyor, the connection between the motor and the compresso-r preferably being in the form of a flexible coupling 26 of any suitable type. The tank 24 may be provided with a pressure gauge 27, and a suitable regulating valve 28 should be inserted in the pipe 23 to clontrol the amount of air supplied to the coa For the purpose of introducing air into the pulverized of forwardly directed ports 29 between the passage 22 and the interior of the casting. Preferably the central Vports of the series should be of somewhat .greater diameter than the end ports, as it has been found in practice that better results can be obtained with such an arrangement. It has also been found that it is an advantage to introduce the air intov the bottom of the column of coal. as the material in this region has a greater density as it .is delivered from the conveyor stallation. `As the distance through which the coal is to be conveyed increases, there should be a greater packing or sealing effect coal, there is provided a series behind the jets in order that the higher pressure air which is necessary for such increased distances should be forced into the coal and be prevented from flowing through the screw conveyor' toward the hopper. This result may be obtained by locating the ports at a greater distance from the end of the screw conveyor. l

Attached to the front face of the annular casting 21 is a tapering casing or chamber 3() to thevouter end of which is connected a pipe 31 through which the fiuent fuel may be distributed to suitable branch conduits through which it may be carried to the points whe-re it is toA be utilized. The main conduit 31 may be brought back to the supy ency of the coal.

Vwhen the pressure on the air and the size such for instance as the character of material, the distance to which it is to be conveyed, its velocity and volume.

In the operation of the apparatus described above, the hopper 13-1is filled with pulverized coal and by means of the damper 14 the iiow of-coal to the screw conveyor 15 may be controlled. While the coal is being fed by the screw conveyor, the compressor 25 is in operation to maintain the air which is to be supplied to the coal under the required degree -of pressure in tank 24. The air flows from this tank and is discharged through the ports 29 where it becomes thoroughly intermingled with the pulverized coal as the latter leaves the end of the screw conveyor. Owing to the packing action pro- I duced at the discharge end of the conveyor or immediately bey-0nd it, the air will be prevented from passing through the casing to the hopper, so that the coal will not be aerated until 'after it has been discharged from the conveyor.

The quantity and pressure of the air may be regulated by means of the valve to the proper amount to reduce the required fluo-od results are obtained and number of the air ports are such that air enters `the conduit to the extent of about six or eight times, by volume, the amount .of coal passing the ports. When the fuel is discharged from the conveying conduit into a receptacle which is open to the atmosphere, much of the air escapes gradually from the fuel so that the fuel collecting in the receptacle would ulitmately consist of coal greatly in excess of air by volume.

On account of the tendency of the coal to pack when it is not aerated, the supply of air should be turned' on before the screw conveyor is started into operation; for otherwise, the coal which is fed beyond the discharge end of the screw conveyor might become sufficiently packed to prevent it from being conveyed through the system;

The air which is supplied tothe coal as the latter leaves the screw conveyor will be so thoroughly intermingled with the pulverized coal as to Aform a sluggishly fluent mass, and the screw conveyor, though of very short length compared to the length-of the conveying conduit exerts continuous mechanical pressure on the entire column of fuel throughout the length of the conduit. By reason o-f this'l continually applied mechanical pressure'and the fluent condition of the fuel, the latter will be moved along thr-ough the conveyor conduit throughout the length of the conduit even thong the conduit be of great length and have in it stretches which rise to substantial elevations. At the desired points in the conduit branch conduits' lead to the points of use of the fuel and each of these branch conduits 05 may be contr-olled by diverting or distributing valves. The semi-fluid or sluggishly fluid characterv of the fuel thus permits of the use of a conveying system which is vastly more simple than those forms of conveying apparatus lheretofore commonly employed,and this simple formlof conveying apparatus is specially desirable in that it contains no moving parts whatever beyond the point ofy application of the mechanical pressure for forwarding the column of fuel. At the points of use of the fuel where it is delivered from the conveyor system, the fuel retains its fluent condition and may be utilized the more readily forthat reason. 'If it is caught in a receptacle as it flowsv stices between the particles of coal and thus 9U giving to the mass its fluent state.

2. A fuel in a sluggishly fluent state consisting of an intimate mixture of finely divided coal and air at a pressure in excess of atmospheric, the air filling the interstices between the particlesof coal and giving the fuel its fluent state. v 3. A fuel in a sluggishly fiuent state consisting of finely dividedcoal and air filling the interstices between the'particles of coal, 1.00

the fuelbeing formed by injecting air into the body of finely divided coal.

4. A fuel in a sluggishly fluent state consisting of finely divided coal and air ,105

the interstices between the particles lof co the fuel being formed by injecting from four to ten unit volumes of air into one unit volume of finely divided coal.

5. A fuel in a sluggishly iuent state oonsisting of finely divided coal and air lling 11o the interstices between vthe particles of co'al, the fuel being formed by injecting approximately six unit volumes of air into one unit\ volume of the finely divided coal.

6. A fuel consisting of a body of finely A divided coal having the interstices between the particles filled with air at a pressure greater than atmospheric pressure. a

In testimony whereof I aiix m si ature.

v ALONZO Cr...p N ON.

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