US1751525A - Apparatus for pulverizing coal or other fuel - Google Patents

Description

MarchZS, 1930. J MULLIN 5 APPARATUS For: PULVERIZING COAL OR OTHER FUEL Filed March so, 1929 :5 Sheets-Sheet 1 J mam.

March 25, 1930. J. MULLIN 1,751,525

APPARATUS FOR PULJERIZING COAL OR OTHER FUEL Filed March 50, 1929 5 Sheets-Sheet 2 I [AWE/V708 S y'- MaZZin J. MULLIN March 25, 1 930.

APPARATUS FOR PULVERIZING. COAL OR OTHER FUEL Filed March 50, 1929 3 SheetsShet 3 7G, is

Patented Mar. 25,- 1930 UNITED sr-A come mm, or nus-mm, ENGLAND Arum-rue iron runvnmzine con. on ornna rum.

Application fled March so, 1929, Serial no.

This invention relates to apparatus forulverizing coal or other fuel into powdered orm for use more particularly in connection with thefiring of furnaces and the like, the chief object being to provide a simple-and more eflicient constructional form of apparatus of this character.

According to this invention, thereis provided apparatus comprising a rotatable drum adapted to'receive the fuel and havin internal means to effect the ulverization t ereof, and also having circum erential slots or openings in its periphery intermediate its ends to permit the discharge of the pulverized fuel. Other features of the invention will appear from the following description and appended claims.

In order that the invention may be clearly understood and readily carried into effect, the same will now be described more fully, by way of example, with reference to the accompanying drawing, in which Figure 1; and

Figure 1 is a longitudinal vertical sectional view of apparatus embodying the in- 2 vention;

Figure 2 is a plan view corresponding to Figure 3 is an elevation taken at right angles to Figure 1.

Referring to the drawings, the apparatus comprises a longitudinal rotatable drum (1 havin conical ends 6 and an intermediate cylin rical portion 0 connected to the said ends and provided with circumferential discharge slots or openings d. Such discharge slots or openings (1 conveniently are formed by spacedrings c. The drum is filled partly with balls e or the like of steel or other hard material and is; fitted with a preferably detachable lining f of chilled cast iron, steel, hard rubberor other appropriate material having spherical or'other projections. g to impart to the said balls a risingand falling motion in conjunction with similar projections on the intermediate portion 0, during rotationof the drum and thereby effect the pulverization of the fuel, the said lining being secured to the cylinder by means of bolts or other suitable fastening means. The cylinder a is supported axially at each end theressnsvo, and in Great Britain April 2, 1928,

of by preferably water-cooled pedestal'bearings h on a bed-plate 11, but the drum may be provided with circumferential tracks and be supported on rollers, according to requirements. The drum may be rotated, as by means of toothed gearing j, 70 and shafting Z-operated by a preferably variable speed electric motor m, but any other form of prime mover may be employed. In the example shown, the shafting Z is operated from the motor b a chain drive n. Coal or other fuel in t e form of relatively small cubes or lumps is fed into a relatively fixed hopper 0 associated with the drum at one end thereof, suitable feeder gear p being adapted to act on the fuel to feed the same into the drum so as to be pulverized, the fine fuel falling through the aforesaid openings at in the drum into the lower portion of an annular chambergsufroundingthe intermediate portion 0 of the drum, the said lower portion of the chamber 9 being provided with an automatic valve 1-. The said valve, which is shown pivotally mounted at s, is so adapted as to permit the weight of fine fuel to force it open and fall into an air supply pipe or conduit tleading to one end of the drum (1, the said valve being also so adapted as to provide against any reverse flow of the air, passing through the said conduit, entering the chamber 9. Such discharged fine fuel is caught by the current of air passing through the said conduit which is connected to a fan u disposed exterior-1y of the drum and driven by the aforesaid variable speed electric motor or other prime mover as by means of a chain drive 1),, or driven by a separate electric motor or other prime mover if desired. The disposition of the fan exteriorly of the cylinder and its arrangement so that it only forces .the air through the machine, serves to ensure less, wear and-tear thereof than in the case of the existing type of fan which, although exterticles of requisite fineness may be carried forward through a classifier eduction pipe w and outlet pipe in to the furnace, storage bunker or other suitable place. If desired, the air forced through the machine may be heated in order to dry the fuel and increase the rate of pulverization. In order to'provide against the leakage of powdered fuel at the trunnions or journals of the drum air may be led from the fan discharge pipe to annular chambers y afforded, for instance, around the relatively fixed inlet and discharge pipesassociated with the ends of the drum, so that any leakage will be into the .drum from the said annular chambers owing to the slightly higher pressure therein. Leakage of powdered fuel at the joints of the annular chamber 9 with the drum is also prevented by air at fan discharge pressure being admitted to annular chambers 2 arranged around the said joints, the pressure in the said chambers being greater than the pressure in the chamber 9. The feeder gear ;0 arranged with respect to the hopper 0 may be operated in any appropriate manner, such as, for instance, by means of a chain a driven by worm reduction gear at b from an extension of the main driving shaft Z of the apparatus, the chain drive in the example shown including a spring clutch device C. 1

It will be obvious that the output of the machine may be varied by altering the speed of the motor or other prime mover and also by controlling a slide d associated with the fuel supply hopper. Further, the secondary air for complete combustion of the fuel in the furnace, when direct firing is resorted to, may be taken from the discharge pipe of the fan at a point, such as at 6, between the fan u and the valve 1', the supply being'regulated as by a damper or dampers in the said pipe. The fineness of the fuel may be controlled by regulating the air to the drum.

I claim 1. ,A ball and drum pulverizing mill comprising a rotatable drum, balls therein, and means for delivering material into one end of the drum, the drum having imperforate conical end portions and an intermediate cylindrical portion which is in free communication with the end portions and is provided with openings through which pulverized material is discharged.

2. A ball and drum pulverizing mill comprising a rotatable drum, balls therein, and means for delivering material to the drum, the drum having imperforate conical end portions and an intermediate cylindrical portion consisting of axially spaced rings providing circumferential discharge openings.

3. A drum and ball pulverizing mill comprising a rotatable drum, balls therein, and means for delivering material to one end of the'drum, the drum having imperforate conical end portions and an intermediate cylindrical portion provided with discharge openings and provided upon the inner surface of the conical end portions, with a lurality of projections whereby to cause the alls to rise and fall as the drum rotates.

4. A ball and drum pulverizing mill comchamber, a conduit extending past said annu-,

lar chamber and arranged to receive material discharged past said valve, the conduit being connected at one end to one end of the drum, and means for delivering an air blast through the conduit.

5. A ball and drum pulverizing mill comprising a rotatable drum, balls therein, means for delivering material into one end of the drum, the drum having circumferential discharge openings between its ends, an annular chamber surrounding the discharge portion of the drum and provided with a non-return valve permitting discharge ofmaterial from the chamber, a conduit extending past the annular chamber and arranged to receive material discharging past the valve, the conduit having one end connected to one end of the drum, means for delivering an air blast through the conduit, and means at the dischar e end of the conduit for receiving material t erefrom and classifying the same, permitting the larger pieces of material to return to the drum and the smaller pieces to be carried to a point of dischar e.

6. A all and drum pulverizing mill comprising a rotatable drum, balls therein, means for delivering material into one end of the drum, the drum being provided between its ends with circumferential discharge openings, an annular chamber surrounding the discharge openings to receive the material passing therethrough, annular recesses around said annular chamber at the joint between the same and the drum, annular recesses around the bearings of the drum, and means for supplying air under pressure to said recesses to prevent leakage of material.

JOHN MULLIN.

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