US2176824A - Fuel conditioning and burning apparatus - Google Patents

Description

3 w. I. SALLEE 2,176,824

FUEL CONDITIONING AND BURNING APPARATUS Filed Oct. 10, 1935 5 Sheets-Sheet 1 IN VENT OR h/Easnsd: 504455; Y

QATTORNEY 0d. 17, 1939. w 1, SALLEE 2,176,824

FUEL CONDITIONING AND BURNING AIPARATUS BY h essrsz I 604155,

w. l. SALLEE 2,176,824

FUEL CONDITIONING AND BURNING APPARATUS Oct. 17; 1939.

Filed Oct. 10, 1935 5 Sheets-Sheet 3 f INVENTOR. WEBSTER I. SALLEE ATTORNEY.

Oct. 17, 1939.;

w. SALLEE 2,176,824

FUEL ONDITIONING AND BURNING APPARATUS Filed Oct. 10, 1935 5 Sheets-Sheet 4 INVENTOR. WEBSTER I. SALJLEE H I 5 ATTORNEY.

Oct. 17, 1939. w, SALLEE 2,176,824

FUEL CONDITIONING AND BURNING APPARATUS Filed Oct. 10, 1935 5 Sheets-Sheet 5 INVENTOR. WEBSTER I. SALLEE 6 HIS A I TTORNEY.

Patented Oct. 17, 1939 UNlTED STATES PATENT OFFECE FUEL CONDITIONING AND BURNING APPARATUS 4 Claims.

This invention relates to a system of and apparatus for burning pulverized, gaseous and liquid fuels selectively or in predetermined combinations with each other and for automatically proportioning the correct amount of air for combustion of each fuel or each combination of fuels, and automatically creating the necessary turbulence for proper combustion and application of the resultant heat.

More particularly the invention relates to an apparatus in which the selective combinations of said fuels and efficient utilization of the resultant mixtures can be obtained without interruption of the operation of the apparatus.

The principal objects of the present invention are to continuously transport solid carbonaceous fuels, to separate tramp iron, magnetically responsive foreign material and oversize pieces of fuel therefrom during transportation, to continuously feed the fuel into a pulverizing mill and pulverize it in the presence of preheated air and discharge the resultant mixture of preheated air and pulverized fuel with proper turbulence through a plurality of fuel burners in desired adjusted proportions of fuel to each burner concurrently, and to provide secondary air to the burners automatically in fixed proportional relationship to the feed of the pulverized fuel thereto.

Another object is to accomplish each of these results in a more efficient manner with an apparatus which is simple in construction, compact and highly efiicient in operation.

Other objects and advantages will become apparent from the following specification wherein reference is made to the drawings in which Fig. 1 is a top plan View of an apparatus embodying the principles of the present invention;

Fig. 2 is a side elevation of the apparatus illustrated in Fig. 1;

Fig. 3 is a right end elevation of the apparatus illustrated in Figs. 1 and 2; and

Fig. 4 is an enlarged plan view of the air inlet control valve of the present apparatus.

1 Fig. 5 is a side elevation of the fuel gun and secondary air housing, part thereof being shown in section for clearness in illustration;

Fig. 6 is an end elevation of the gun and housing illustrated in Fig. 5;

Fig. 7 is a top plan view of the V-belt driving mechanism, attrition mill, and chain feed separator;

Fig. 8 is a fragmentary end elevation of the upper portion of the structure illustrated in Fig.

7, part thereof being shown in section for clearness in illustration;

Fig. 9 is a fragmentary side elevation of the upper portion of the structure illustrated in Fig. '7.

Referring to the drawings, the apparatus includes a plurality of precombustion chambers 1 arranged to discharge into the combustion chambers of respective boilers with which associated, any number of precombustion chambers and boilers being utilized. For the purpose of illustrating the present invention, however, four such precombustion chambers are shown. Each of the precombustion chambers is provided with secondary air housing 2 at its inlet end, each of which housings 2 receives a fuel gun 3 which discharges centrally and axially of the precombustion chamber with which associated.

As set forth generally in the above objects, each fuel gun mechanism, as more fully de scribed hereinafter, is operable to discharge liquid fuel, gaseous fuel and powdered fuel separately or in combinations with each other, While properly aerating the fuel and creating the necessary turbulence. If powdered fuel is to be used it is preferably pulverized, mixed with preheated air and discharged through the fuel guns 3 continuously.

In order to continuously supply the pulverized fuel, a magnetic chain feed and separator, such as more fully described hereinafter, is utilized.

Briefly, the magnetic chain feed and separator comprises two parallel spaced chains 4, each of which is provided with prongs 5 extending toward the opposite chain, the prongs cooperating to form a suitable grill. The chains are mounted for movement together so as to pass beneath a supply hopper 6 from which solid fuel to be pulverized is fed onto the chain. Further along the path of movement is a receiving hopper l, which, through a suitable duct 8, discharges into the pulverizing mill 9. Along the portion of the path of travel of the chains coextensive with the feed hopper l is a magnetic field created by electromagnets I0 arranged to magnetize the prongs of one chain at one polarity and the prongs of the other chain at the opposite polarity so that adjacent prongs along the path of travel constitute opposite magnetic poles. As better illustrated in Figs. 1 and 2, the prongs of one chain are mechanically disassociated and out of contact from the prongs of the other chain. The electro-magnets ID are supported on upright flux conducting standards which terminate at their lower ends, as illustrated, in close proximity to the chains respectively. The coils are arranged with the north poles connected to one standard which lies closely alongside one of the chains and the south poles connected to the other standard which lies closely'alongside the other chain 4. Thus one chain is subjected to the north poles of the magnets only and the other chain to the south poles only of the magnets and, since the prongs of the chains do not contact with each other, the prongs of one chain are magnetized. at one polarity and the prongs of the other chain at the opposite polarity. The hopper I is ar-..

ranged beneath the chains so that material deposited on the chains falls between the prongs into the hopper and is thus screened by the prongs of the chain. Thus fuel to be pulverized is continuously discharged from the hopper 8, screened to the proper size as it travels along with the chains 4 and discharged into the hopper 1. During this operation tramp iron or other magnetically responsive material is retained on the chain until the chain passes beyond the limits of the feed hopper l whereupon it is out of the magnetic field and the iron is discharged from the chain.

As explained above, the solid material thus graded and separated passes through the feed conduit 8 into the pulverizing mill 9. The pulverizing mill is preferably of the air swept attrition type, the air current therethrough being maintained by an exhaust fan ll. The pulverizing mill preferably is provided with a plurality of pulverizing compartments, the air flow through each compartment being separately controlled by means of suitable external hand operated wheels [2 so that the desired fineness of grind for the particular grade of fuel being supplied to the mill can be maintained accurately.

In some instances, a certain amount of moislture is retained in the fuel bed to the mill and this deleteriously affects the pulverizing operation. In order toremove any excess moisture from the fuel during the grinding operation, the air inlet to the mill is placed in communication with an air conduit l3 which, by virtue of branches !3a and Hit), receives the preheated air so that the grinding operation is carried on while the bed of attrition is continuously swept by an ever changing stream of preheated air. Consequently, not only is the grinding operation more eflicient and also the fuelis more finely pulverized but the fuel is more uniformly distributed in the air stream issuing from the mill.

For supplying the preheated air, the precombustion chambers l are provided with housings I4 forming with the chamber walls, compartments which are in communication with the conduits I30: and 93b respectively and which are open remote from the conduits to the outside air. Therefore, all air supplied to the mill is drawn from around the exterior of the precombusticn chambers and is thereby preheated and at the same time recuperates some of the heat which would otherwise be lost from the precombustion chambers. The specific arrangement of the chamber and compartments is disclosed in United States Letters Patent No. 1,923,330, issued to me on August 22, 1933.

Secondary air is supplied to. the secondary air housings 2 from a suitable power driven blower type fan 55. Since it is desirable that the secondary air be free from eddy currents and swirling as it enters the secondary air housings 2, an even pressure chamber is provided which operates, in effect, as the even pressure chamber in Letters Patent No. 1,923,330, issued to me on August 22, 1933. By eliminating such currents, the shape of the air streams discharged from the secondary air housings 2 can be more accurately controlled by suitable directional vanes'mounted Within the housings 2. In the present instance, the even pressure chamber is supplied, in effect, by the air conduit l6 and branch conduits I60 and itb, the capacity of which is so large that the initial swirling of the air as it leaves the fan is is overcome and the air discharged into the secondary air housings is discharged by virtue of the pressure head with the initial velocity head createdat the fan so translated as to cause no deleterious effect in the control of the discharged stream. 7

For compactness and for accurate relation between the rate of driving of the mill and secondary air fan, the same are preferably driven from a single motor ll which drives at constant speed.

The magnetic chain feed and separator, however, is driven at variable speed from a different source of power, for example, the motor E8. The desired changes in the rate of drive of the magnetic chain feed and separator are effected through a variable speed transmission, such, for example, the V-belt reduction mechanism 29 shown by way of illustration. As is well known, in such mechanisms a driving pulley 2i and driven pulley 22 carry a belt of V-shaped cross The driving pulley 2! is arranged 50" section. that the end flanges thereof may be moved toward and away from each other, these flanges being flared complementary to the belt. Thus as they are moved together the belt rides nearer the circumference and consequently is driven at is provided, the motor 23, in turn, being responsive to a suitable boiler pressure operated electrical control 23b or temperature operated electrical control 230, shown diagrammatically in Figs. 7 and 9. The pilot motor 23 can eifect variations in the speed relationship between the pulleys 2| and 22, as shown more or less diagrammatically in Fig. 7. A lever 29 pivoted intermediately of its ends has conventional sliding ring-and-pin connections as at 2| and 22' with a flange of each pulley, and the lever extends beyond the connection 2| to a nut 23" on a shaft 23' which is driven by the motor 23. The nut is maintained against rotation on a threadedportion of the shaft so that turning of the shaft in one direction increases the speed of the driven pulley, and movement in the opposite direction decreases such speed. It is desirable, however, that the admission of air to the grinding mill and the admission of secondary air to the air housings 2 'be maintained in predetermined fixed relations to the rate of drive of the chain feed separator. Suitable valves i312 and 55v, therefore, are provided in the conduits l3 and Hi for varying the flow of air therethrough. These valves are driven through a suitable gear, cam, and toggle arrangement, designated generally at 2d and better illustrated in Fig. 4, the mechanism 24 being driven in turn from the pilot motor 23 which drives a worm shaft 23s. This mechanism is so arranged as to open the valve I312 in the conduit l3 to a ill) greater degree as the speed of the magnetic chain feed is increased. Correspondingly, the valve I611 in the conduit I 6 is operated by the same mechanism 24 through the medium of the link 25. Thus the valves in the air inlet conduit l3 and the secondary air conduit i6 are operated in predetermined fixed relation with respect to each other as Well as in relation to the rate of feed of fuel by the chain.

Referring to Fig. 4, it will be noted that the cam 24a of the mechanism 24 may be adjusted circumferentially relative to its driving gear 241) by loosening the bolt 24c and the driving gear 24b is driven by the worm shaft 23a. Thus the position of the valves [30 and i611 and consequently the amount of air for a given delivered speed of the variable speed transmission, may be provided. A linkage 24d is engaged by the cam 24a. and is operatively connected to the rock shaft 242 of the valve i312 for swinging the valve in response to the seating of the cam Ma by the gear 24b. Additionally, if desired for any reason, the relative setting of the valves i312 and 16o with respect to each other may beobtained by changing the length of the rod 25. Since the mechanism 2d may be thus adjusted the proportion of air for the particular fuel or combination of fuels to be used may be provided and once this setting has been made the proportion is maintained regardless of the rate of feed of the particular fuel.

As explained above, liquid fuel is also utilized in the fuel gun and for maintaining the desired pressure head thereon, a suitable fuel pump 26,

I driven by a pulley 27 from a variable speed shaft of the V-belt mechanism, is provided. The pump is connected to a suitable feed conduit 28 leadin to a suitable storage reservoir, the flow therethrough, in turn, being controlled by a valve 29. Leadingfrom the pump is a discharge conduit 35 which, by a suitable T-connection, is in communication with the feed line 3| and lead line 32 which lead to the storage reservoir. A valve 33 is provided in the lead line for regulating the pressure head maintained by the pump at any given speed by means of by-passing part of the fuel back to the reservoir. The line 3! is also provided with suitable valves 34 and 35 for controlling the flow of fuel therethrough to the fuel guns 3. The feed line 3!, in turn, communicates through branches Sid and 31b with preheating coils 3?, each preheatedlcoil being arranged on the outside of the combustion chamber into which the gun with which it is associated discharges. The rate of flow of fuel through each of the coils 3'! and consequently the degree of preheating, is effected by means of valve 38, one such valve being provided on each preheating coil. The fuel oil issuing from the coils 3! passes through the respective valves 38 and feed lines 39 leading to the respective guns.

The preheating coils 3'! and valves 38 and other valve arrangements suitable for effecting these results are more fully described in United States Letters Patent No. 2,064,417, issued to me January 12, 1937, and relating to Apparatus for preheating fluids.

Since the pump 26 is driven from the variable speed of the change speed mechanism, the proportion of secondary air is also automatically controlled in relation to the liquid fuel through the pilot motor 23.

As explained, it is desirable that the change over from solid to liquid fuel be made without interruption of operation. For accomplishing this purpose, the final drive between the change speed mechanism and pump is effected through a clutch 40 operated by a hand lever M. Corre-' spondingly, a clutch 42 operated by a hand lever 42a is provided between the change speed mechanism and the magnetic chain feed separator. When it is desired to change over from liquid fuel to pulverized fuel and vice versa it is only necessary to shift the clutches through the medium of the levers 4i and 42 respectively to the desired positions.

As set forth in the objects, it is desirable that the air and pulverized fuel discharged from the mill be supplied to any one or more of the fuel guns 3 and in any predetermined relation to each other. For accomplishing this purpose, the pulverized fuel and air feed conduit 84, leading from the mill, is provided with control valves 65 and 46 which are independently adjustable. In case of four burners, two such valves 45 are provided, the mixture issuing from the mill being discharged between the two valves. Leading from the valve 45 are two branch conduits i? and 48, respective to different ones of the guns 3. Correspondingly, branch conduits 49 and 5% lead from the valve 56 to different respective ones of the guns 3. Another splitter valve Si is provided between the mill discharge and the valves @5 and 46. Thus all or any portion of the mixture discharged from the mill may be directed toward the valve 55 and all or any portion toward the valve is, thereby initially proportioning the mixture to the respective valves 15 and A6. The amounts supplied to these valves, in turn, are prorated thereby to the fuel guns associated therewith. It should be noted that in each instance, each of the valves is pivoted at its trailing edge in the center of the conduit with which associated and has its edge, which is leading in the direction of travel of the mixture, passed through the conduits free to move entirely to one side or the other of the conduit with which associated. Extending in the direction of travel from the pivotal axis of each valve is an imperforate partition wall so that any sub-divisions of the stream of the mixture passing to opposite sides of the leading edge of the valve are thereafter maintained as separate streams.

It is apparent from the foregoing description that the apparatus herein described provides for the continuous transportation of the solid fuel, the sizing thereof and separation of tramp iron therefrom, followed by proper grinding to the required fineness in the presence of a continuously changing stream of preheated air by which the pulverized fuel is continuously transported to a plurality of selected burners of a group concurrently, and further, for the proportioning of the fuel laden air thereamong, accompanied by the provision of a secondary air automatically in fixed proportions to the amount of fuel discharged.

Referring next to Figs. 5 and 6, the fuel gun 3 and the secondary air housing 2 are shown in greater detail. The secondary air housing 2 com prises a hollow body having an internal sleeve 50 in which the gun 3 may be inserted axially and withdrawn when desired. Air is supplied into the secondary air housing 2 from the fan through a depending conduit M. The housing 2 opens at its forward face into an annular flange 63 which is arranged to be connected to the rear of the precombustion chamber i4. Within the flange 63 are a plurality of directional vanes 64, the vanes being mounted on shafts 65 which extend radially of the flange 53. Each of the shafts 65 is arranged to rotate about its axis to position the vanes in the desired position. The outer end portion 66 of each shaft 65 is bent at an angle to the remainder and engages a notch 51 in an operating ring 68 which is rotatably mounted on the outside of the flange 63. Thus, upon rotation of the ring, all of the vanes tit are adjusted simultaneously.

The fuel gun comprises a tubular body "it! having an interior passage it through which air and pulverized fuel are supplied through a conduit 72 which, when the gun is in operating position, is connected with the conduit is formed on the gun support It. At the forward portion of the gun is a spinner iii having radial blades it which, under the influence of the air and pulverized fuel passing through the gun, impart a rotary motion and cause the spinner to spin at high velocity.

'The fuel gun is provided with a plurality of internal ducts, such, for example, as the duct T'i, which, when the gun is in position, are connected with cooperating ducts, such as the ducts E8 in the secondary air housing 2. Suitable stop cocks are provided for each duct i3 and these are arranged With yoke handles i9. Mounted on the secondary air housing 2 is a ring. 633 having radial arms 8! respective of the stop cocks for the ducts it. Thus, upon rotation of the ring all of the stop cocks are opened and closed simultaneously. The duct 18 in Fig. 5 is controlled by a stop cec's. 32 and supplies lubricating oil to the gun. One of the ducts it is a gas supply duct (not shown) and is controlled by a corresponding stop cook 33. Liquid fuel is supplied through a corresponding duct in the gun and is controlled by a stop cook 34, this stop cock being connected, in turn, through a series of pipes to the pump 25. As heretofore described, and as better illustrated in Figs. '7 to 9, the magnetic chain feed and separator and the pump 26 are so arranged that they may be operated simultaneously or selectively at varying speeds. The chain feed and separator and the pump '26 should be arranged for driving in such timed relation to each other that with the given setting of the driving mechanism of the apparatus, either the pump or the chain feed will deliver the same amount of fuel to the guns. For eifecting this driving, the motor I3 is drivingly connected by suitable belts to to the V-belt reduction mechanism 2%). In this mechanism, the driving pulley 2! drives the pulley 22 and its shaft. Driven by a suitable shaft connected with the pulley 252 is a belt which drives a shaft 92 which, in turn, through a belt. 93, drives the pulley st. Driven by the pulley Qt is a shaft provided with a pulley as which, through the medium of a belt 9?, drives a pulley 98. The pulley so may be drivingly connected to and disconnected frem the magnetic chain feed and separator by the clutch Q2. The pump, in turn, is driven by a puiley 22a on the shaft of the V- belt drive pulley 22. The belt so, in turn, drives the pulley 2? which i arranged to be drivingiy connected to and disconnected from the pump .36 through the medium of the clutch til. Thus the rate of drive of the pump 26 and the rate of drive of the magnetic chain feed separator are both dependent upon the speed of the pulley 22, and each. is driven a fixed timed relation to the speed of the pulley Consequently, by the operation of the clutches ill and 42, either the pump or the magnetic chain feed can be operated as desired, or both may be operated simultaneously. As mentioned heretofore, it is desirable to regulate the speed of the \/-belt mechanism and consequently the rate of supply of liquid or solid fuel to the fuel guns in response to temperatures or boiler pressures and the like. The motor 23, therefore, is operated for changing the speed of the V-belt mechanism and is under the control of the temperature thermostat 230, which is capable of reversing the motor and also under the control of a boiler pressure operated switch mechanism 231), which likewise is capable of reversing the motor. In the form illustrated, the

motor 23 is operated by direct current and the control thereof is diagrammatically illustrated in Fig. 9.

Having thus described my invention, I claim:

1. In a fuel burning system, a fuel gun operable to discharge pulverized fuel and liquid fuel selec tively, a pulverizing mill, neans connecting the mill to the gun to supply pulverized fuel and air thereto, a feed mechanism for feeding solid fuel to the mill, a liquid fuel pump, means connecting the pump to the gun to supply liquid fuel thereto, and means for driving the pump and feed mechanism in predetermined speed relation with respect to each other.

2. In a fuel burning system including a combustion chamber, a fuel gun operable to discharge pulverized fuel and liquid fuel concurrently or selectively into said chamber, a. pulverizing mill, means connecting the mill to the gun, a feed mechanism for feeding solid fuel to the mill, a liquid fuel pump, means connecting the pump to the gun for supplying liquid fuel thereto,

means for driving the pump and feed mechanism in predetermined speed relation with respect to each other, and means for selectively rendering said pump and feed mechanism active and idle.

3. In a fuel burning system including a combustion chamber, a fuel gun operable to discharge pulverized fuel and liquid fuel concurrently or selectively into said chamber,-a pulverizing mill, means connecting the mill to the gun, a feed mechanism for feeding solid fuel to the mill, a liquid fuel pump, means conn cting the pump to the gun for supplying liquid fuel thereto, means for driving the pump and feed mechanism in predetermined speed relation with respect to each other, means for rendering said pump and feed mechanism alternately idle and active selectively, blower means for supplying secondary air to said chamber, and means automatically operable for varying the supply of secondary air from said blower in a predetermined proportional relation with respect to either said pump or feed mechanism.

l. In an apparatus of the character described, a fuel gun, feed mechanism operatively associated with the gun for feeding solid fuel thereto, a pump operatively associated with the gun for supplying liquid fuel thereto, said feed mechanism and pump being driven in timed relation to each other, means for rendering the pump and feed mechanism selectively active and idle with respect to the gun, and means for setting the pump deliver-y prior to operation of the pump to effect discharge therefrom to the gun of a predetermined amount of liquid fuel in relation to the amount of solid fuel supplied by the feed mechanism, whereby a transition from solid-fuelburning to liquid-fuel-burning can be made without resultant variation in the heating eifect of the gun.

WEBSTER, I. SALLEE.

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