US1320963A - Method and apparatus tor eeedito pulvebized fuel - Google Patents

Description

C. H. BALDWIN.

METHOD AND APPARATUS roa FEEDING PULVERIZ'ED FUEL.-

- APPLICATION FILED JAN.26'| 1918.

3 SHEETS-SHEET 1.

C. H. BALDWIN. METHOD AND APPARATUS FOR FEEDINGPULVERIZED FUEL. APPLICATION FILED mus, 19m.

1,32Q,963, A Patented Nov. 4, 1919.

3 SHEETS-SHEET 2- C. H-BHLDWIN c. H. BALDWIN. METHOD AND APPARATUS FOR FEEDING PULVERIZED FUEL.

APPLICATION FILED JAN. 26. [918.

1,320,963. Patented Nov. 4, 1919.

3 SHEETS-SHEET 3.

,. glmavuiux CH .BHLDVWN CLOISE H. BALDWIN, OF CHERRYVALE, KANSAS.

METHOD AND APPARATUS FOR FEEDING PULVERIZED FUEL.

Specification of Letters Patent.

Application filed January 26, 1918. Serial No. 214,006.

To all whom it may concern:

Be it known that I, Cnorsn H. BALDWIN, a citizen of the United States, residing at Cherryvale, in the county of Montgomery and State of Kansas, have invented certain .new and useful Improvements 1n Methodsratus for feeding pulverized fuel to fur-' naces.

Apparatus of various types have heretofore been provided or contemplated for the feeding of pulverized fuelto furnaces and certain types of these feeders consisted in the employment of a suitable character of conveyer which is arranged in a casing or housing and operative in such manner as to carry the pulverized fuel above an outlet and discharge this pulverized material in a shower across an outlet from the casing through which a draft of air is forced by pressure admitted to the casing, usually the draft being projected from a blast nozzle disposed on the side of the casing opposite the feeder outlet so that the air from the blast would'cross the shower of fuel in the casing and the lighter particles ofthe fuel would be carried by the air as a vehicle into and through the discharge outlet of the feeder to a furnace connected to the feeder outlet. These types of pulverized fuel feeders involving the utilization of 'a blast of air caused to cross the flowing pulverized fuel are subject to certain objections, among which may be mentioned a loss of efficiency owing to the discharge of the air from the blast nozzle in the enlarged chamber of the.

casing so that the air was caused to move at a comparatively-low rate and with less carrying efficiency through the feeder outlet. Another objection to the blast type of apparatus is that the compressed air has such a large per cent. of moisture t a 0n the expansion of the air in the feederfihtrmber or casing, the moisture was condensed and would collect on the coal particles and these becoming moistened, would adhere to the walls of the chamber and conveying mechanism and thus materially interfere with the discharge of the ,fuel. .Again, in this type of apparatus, when it is necessary to interrupt the supply of fuel to a given furnace, this cannot readily beaccomplished without entirely cutting off the blast of air and therefore, the destruction of the feeder nozzle where it remains projecting in the interior ofthe furnace and is subjected to the high temperatures which would result in the destruction of the feeder nozzle in the event that the current of air is lowered beyond' such a quantity as will be necessary to keep the discharge nozzle at such a temperature as to resist attack by the heat. In the blast type of feeder, where the air is caused to pass from the discharge nozzle across the shower of fuel, air which must necessarily pass to the feeder outlet, cannot be cut off to the desired degree and so will carry with it, if only partly cut off, a quantlty of fuel to the furnace. Again these types of apparatus do not afiord a ready means for controlling the uantity of fuel or regulating the mixture 0 fuel and air to obtain the best results in operation.

In view of the well-known limitations and objections to pulverized air feeders of the type involving a blast of air being directed across a shower of coal dust, it is one of the objects of the present invention to provide a method and improved means for the eflicient feeding of pulverized fuel to a ser es of furnaces by the employment of a suction or injector principle in which a controllable volume of air is discharged into a feeder outlet leading to a furnace so that a suction isproduced in a conveyer housing or casing and by which suction a controllable quantity of the powdered fuel is drawn from the feed chamber or mechanism into the injector or feeder nozzle and thence delivered into the furnace.

JAnother object is to provide in a pulverized fuel feeding system for the reduction or elimination of the feed of fuel from the conveyer to any one of a series of furnaces when desired without endangering the fuel feeder nozzle to destruction by the heat by.

supplying a sufiicient quantity of air to the nozzle without the conveyance of fuel through the nozzle which it is desired to temporarily out out. Another object of the invention is to provide for the control of the tendency of the suction blast to create a vacuum within the apparatus and to provide for the entrance Patented Nov. 4, 1919.

i not shown, whereby of the necessary quantity of air into the ap- Earatus in the event that the structure may.

e of such tight construction as not to in here'ntly admit of a flow of air into and through the conveyer and feeder housing.

With the above and other objects in v ew as will be rendered manifest in the following specification and which will be clearly comprehended by those skilled in the art, the present invention consists in the method of and means for feeding pulverized fuel to furnaces by the utilization of a suction of air and 'a device to provide for the suction effect and further consists in the whole, the construction, the combination, the elements and in details and parts more fully hereinafter described, one embodiment of the apparatus andembodiments of details of modified form being illustrated in the accompanying drawings, in which,

Figure 1 is a vertical transverse section through a system in which thepresent inform of valve for controlling the nozzles,

Fig. 7 is a modified form of nozzle con- 7 struction,

Fig. 8 is a sectional detail view of'a modified form of the feeder head and f Fig. 9 is a detail view inside elevation of a modified form of fuel carrier.

While the present invention may be utilized in a system of any suitable construction for feeding a pulverized fuel to a furnace or furnaces, it is illustrated diagrammatically in Fig. 3 as involved in an organization comprising a fuel bin B from the bottom of which leads a conveyer housing 0 in which there is rotated any suitable form of conveyer, as forinstance, a screw, the pulverized fuel is carried from the bin to one or more feeder units F of suitable construction disposed in the conveyer line C and from each of which units there is extended a feeder head H, Fig. 1, from which. leads a nozzle N to a respective furnace of a boiler, for instance, A.

Within each of-the feeders F- is arranged any suitable device for carrying the coal dust upwardly and discharging it in av showeracrossthe outlet 0 of each feeder, this device being illustrated in Fig. 1 as a section through the conveyer system comprising an endless chain of buckets 2 mounted in any suitable manner on a sprocket wheel 3 which is secured on the, worm or screw shaft 4 which is extended through the conveyer housing (J, the endless conveyer 2 being arranged in a casing which'forms the unit F and comprises in one form a head member 4 cover ing an upper sprocket 5 over which the conveyer or bucket belt.2 runs, the head being detachably connected to an intermediate section of the housing 6 which has a removable bottom 7 the latter being provided with a tap-hole. 8 at the bottom to provide for the removal of any obstacle or accumulated debris at the bottom of the casing of the feeder unit. Amodified form of device for discharging the coal in a shower within the feeder across the outlet 0 therefrom, is shown in Fig. 9, as comprising a substantially circular bucket wheel 2' which is concentrically fitted upon the conveyer screw S in the housing and is adapted to pickup the coal dust from the bottom thereof and carry it upwardly and discharge it at one side on a level apprgxitnatly'the same as the center of the out- The 0 eration of the device thus far described is rendered substantially continuous in that pulverized fuel is led from the bin 'B' and carried by the conveyer devlce 1n the casing section C to each of the feeder units therein, the excess material or that portion not passing into the outlet from the feeder unit being advanced by the conveyer to one end thereof where it is elevated by any suitable elevated or other conveying device illustrated at E, and thence returned by an .upper conveyer G to thebin: s

The present invention resides more particularly inthe provision of means and in the method of causing the transference of the pulverized fuel from the conveying and feeding device to the furnace or furnaces at the boilers A and the mechanism for let 0 thereof, and this suction 0 air in the head H therefore inducts a quantity of the pulverized material which is showered across the outlet from the feed unit into the nozzle head H and thence through the nozzle to its associated furnace.

One. form of device. for securin this induction effect and the injection 0 the fuel dust from the nozzle into the furnace is accomplishing this is illustrated as compris- -is'provid ed with a series of apertures, one

each for the air pipes 10, the base plate being detachably mounted against a seat on the head H and secured there by a clamp- I ing disk 12 threaded into a threaded portion 13' of the head H. To control the passage of air from the disk or base plate 11 to each of the air tubes or pipes 10, I provide any suitable form of valve or gate here shown as comprising a short tubular member 17 having a flange 15 the shoulder of which is engaged by a gland 16 which threads to the threaded part 13 of the head to hold the valve member 17 with its upper end bearing snugly against the lower surface of the pipe base 10, this valve'member having its upper end rabbeted through an arc of approximately 180 degrees or co-extensive with the arc of apertures to which the ends of the pipes 10 are connected in the base 11 so that by turning the valve member 17 as for instance, by a lever 18 connected thereto, each .of the apertures in the base 11 for the pipes 10 may successively be cut off to control the discharge of air through the pipes, the supply of air coming from a pipe 20 extending upwardly from a T-connection 21, the upper end of which pipe 20 is fitted within the turnable valve member 17, the lower end of which is provided with a gland .22 fitting the pipe 20. There is shown in Fig. 7 a slightly modified form of air pipe construction in which 10 represents a series of concentric air pipes through which air may pass from the source of supply into the head H an nozzle N of the injector.

By means of-the air supply and air control means above described, it will be seen that the amount of fuel induced to enter the feeder head H may be readily determined by. the control of the supply of air to the air pipes 10 and moreover, it will be seen that the amount of coal passing into the head H will remain substantially in constant ratio or proportion throughout the entire range of operation of the feed controller which includes the valve member 17, so that when only a small proportion of fuel is desired, it will be clear that the suction effect in thefeeder head will be reduced in proportion by the cutting off of the air feed pipes 10 and when a larger proportion of fuel is desired, the suction may 'be increased by the opening of more air pipes 10.

In the event that the system in which the feed unit or units maybe organized is constructed so as to be too tight to admit of a flow of air into the casing or housing in response to the suction produced by the injection nozzle, while discharging air there to the interior of the housing or for observation of the action of the parts during operation.

It is desirable that in the event it becomes necessary to cut off the supply of fuel to any of the furnaces connected in the system, suflicient air may be provided to pass to the nozzle projecting into a fire box of a furnace to prevent the destruction of the nozzle by the intense heat and this is readily accomplished by my invention, by the reduction of the suction created in the apparatus through means of, an auxiliary valve 25, Fig. 1, which is adapted to seat, for instance, at the edge of an aperture 11 formed centrally in the base plate 11, this valve being mounted on the upper end of a stem 26 passing down through the pipe 20 and through the connection 21 which is provided with 'a bushing 27 through which the stem 26 extends and which latter is pro vided on its ends with a hand wheel 28 whereby the stem may be turned and by reason of its threaded engagement with the bushing 27 forced to move toward or from duced and the quantity of fuel drawn into the head from the feeder will be propor-.

tionately lowered as the valve 25 is opened until, if desired, the valve may be opened to such a position as to prevent the induction ofany fuel to the head H while at the same time, air may be discharged through the pipes 10 into the feeding nozzle N of the furnace and the latter-protected by the air supplied.

While the controlling mechanism is shown in Fig. 1 as disposed in relative close position to the head H of the feeder. there may be instances in Which it would be desirable to arrange a manually operated controlling member at a position somewhat remote from the feeder unit and such an exigencvmay be system including operating means for continuously advancing the .,fuel, a feeder, for each furnace, 'coacting with the said means and operative to advance the fuel and also to shower it in a diverted path, a feeder head for each furnace and connecting it to the conveyer system andhaving its intake so disposed that the diverted fuel is showered past it, and pneumatic means disposed in each head for discharging airtherein to cause induction of fuel and air at the intake, said pneumatic means comprising individually controllable nozzles whereby the quantity and the quality of the mixture may be varied without variation of the feed by the conveyer system.

2. In an apparatusqfor feeding pulverized fuel, a c'onveyer system, a feeder head having its intake so connected as to receive fuel therefrom, and means for discharging a variable amount of air into said head to cause induction at the intake end thereof comprising, a source of air supply, a plurality of pipes connected to said supply and having their discharge ends disposed toward the discharge end of said feeder head and a valve for closing any desired number of said pipes. 3. In an apparatus for feeding pulverhaving its intake so connected as to receive fuel therefrom, and means for discharging ized fuel, a conveyer system, a feeder head a variable amount of air into said head to cause induction at the intake end thereof, comprising a source of air supply, a base plate disposed at the end of said air supply, a plurality of openings in said plate, pipes connected to said openings, and having their discharge ends disposed Within, and opening toward the discharge end of said head, and a valve on said plate adapted to close part or all of said openings.

4. In an apparatus, for feeding pulverized fuel, a conveyer system, a feeder head having its intake so connected as to receive fuel therefrom, means for discharging a variable amount of air into said head to cause induction at the intake end thereof and means for relieving the induction at the ini take end of said he'adwhile air is being discharged therein whereby the discharge end of said head may be cooled when the fuel is not "being fed. J

5. In an apparatus for feeding pulverized fuel, a conveyer system, a feeder head having its intake so connected as to receive fuel therefrom, means for discharging a variable amountrof air into said head tocause induction at the intake end thereof, and aux iliary means for discharging air into said head to counteract the induction in andfor the purpose described.

In testimony whereof I affix my signature.

CLOISE H. BALDWIN.

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