US2038594A - Pulverizing apparatus - Google Patents

Description

April 1936- I R. D. NICHOLS 2,038,594

PULVERIZING APPARATUS v 2 Sheets-Sheet 2 Filed May 22, 1933 /NVENTOR:

26 Richard D. Nichols my. '7 m- ATT'Y 1 air created by the blower. creased by the removal of the pulverized material Patented Apr. 28, 1936 PULVERIZING APPARATUS Richard D. Nichols, Columbus, Ohio, assignor to The Jeffrey Manufacturing Company, acorporation of Ohio Application May 22, 1933, Serial No. 672,093

1 Claim. (01. 83-11).

The improved pulverizing apparatus represented by the present invention is designed to effect a very substantial increase in efliciency of the forms of apparatus of this general type heretofore employed, through increasing the rate of feed of material to the pulverizing devices utilized in the machine, and imparting to the material an effective preliminary breaking up prior to the complete pulverization of the said material.

The present invention relates to a type of grinding or pulverizing apparatus in which the material to be pulverized is fed, in suitably small fragments, to rotary pulverizers operating in opposite directions, to the exterior of which pulverizers the material is fed, and from the interior of which the pulverized material is removed. The removal of the pulverized material is accomplished by a flow of air traversing the pulverizers in opposition to the centrifugal force of the pulverizers acting on the said materials. Machines of this general type include, therefore,

a casing forming a single pulverizing zone in which the above-indicated pulverizers are rotated at high speed. The casing has an inner cylindrical wall provided with a hard, abrasive surface or liner, against which the material to be pulverized is impacted by the action of the rotary pulverizing elements. The material to be pulverized is fed to the interior of the cooperating rotatable'elements, and the pulverized material is .discharged substantially radially therefrom by a blower associated with one of the elements. In

the operation of a machine of this design can-- trifugal force acts in conjunction with the flow of The efliciency is inwhich is effected by creating a flow of air through the unit in opposition to centrifugal force acting on the material.

' It has now been discovered that a further substantial increase in the efllciency of the machine may be obtained by providing the rotary pulverizing element positioned adjacent the intake side of the pulverizing chamber, with a pluralityoi flanges arranged to act with a shearing force on the incoming material and to impact such ma-Q, terial against the aforesaid lining of the crushing zone to effect a more thorough preliminary breaking up of the material than has heretofore been the case.

It will be understood that the apparatus is designed to operate on any kind or class of material which it is desired to pulverize, and which is of the requisite degree of softness and friability.

The air flow through the pulverizing zone is established by means of a suction fan located at 7 one side of thepulverizing zone, the fan being positioned adjacent the rotary grinding device on the discharge side of the casing, but separated therefrom by an auxiliary wall having an air passage through the center thereof in substantial registry with the air passage through the center of the rotor.

The invention will be more readily understood by reference to the accompanying drawings, in

which:

Fig. 1 is a vertical section through a pulverizing apparatus constructed in accordance with the present invention, driving motors for the rotary pulverizers being shown in elevation;

Fig. 2 is a sectional view taken generally on the line 2-2 of Fig. 1;

Figs. 3 and 4 are perspective views of opposite faces of the fan side rotor element of the pulverizer shown in section in Fig. 1;

Figs. 5 and 6 are perspective views of opposi faces of the intake side rotor element of the pulverizer of. Fig. 1; and

Fig. 7 is a side view showing the driving means for the feedmechanism.

The, pulverizer includes pulverizing apparatus, feeding mechanism therefor, and cooperating fan elements adjacent the intake and outlet passages, the pulverizing apparatus being located intermediate the fans.

As shown in Fig. 1, a hopper I is provided to receive the material to be pulverized, which, for

purposes of illustration, may be specifically coal.

of the pulverizer I.

The feeder 2 comprises a rotary element l3 mounted on the shaft H. A plate l5, pivoted at l6, rests loosely on top of the rotary element l3. Another plate I'I pivoted at II is located below the rotary element It. The plate I! is yieldingly supported by the roller l9 pivoted to the inner upper end of the slide rod 20. The rod 20 slides through a wall of the throat l and also through a strap 2| secured to the bracket plate 22. A nut '23 screw-threaded onto the rod 20 acts as an adjustable abutment to limit the inward movement of the roller IS. A spring 24 between the nut 20 and stationary strap II is compressed when fed below the feed roll l3 and depresses the plate H.

A permanent magnet 25 attached to a removable cover 26 is placed in the path of the descending material to remove tramp iron from the latter. Such permanent magnet and the feeding apparatus adjacent the same as shown in Fig. 1, may be the same in construction and operation as that disclosed in the patent to Austin A. Holbeck, No. 1,855,171, granted April 19, 1932. If desired, of course, an electromagnet may be substituted for the permanent magnet and arranged to be energized whenever the feeding mechanism 2 is operated.

A hollow circular closure 21 for the feed side of casing 6 is provided with a platform 26 on which is mounted the motor 29 The shaft 30 of the latter extends inwardly and carries at its inner end the feed side rotor element 3 I, which is shown in section in Fig. 1 and in perspective in Figs. 5 and 6. When the motor 29 is operated, the rotor 3| is rotated relatively to the casing 6 and the closure 21 in a direction opposite to the direction of rotation of the fan side rotor element I2 which is driven by motor l0. The fan side rotor element |2 is shown in perspective in Figs. 3 and 4.

The feed side rotor element 3| together with the closure 21 and the motor 29 may be moved axially of the shaft 30 and then swung laterally on vertical hinges 32 so that both rotors will be freely accessible for inspection, repair or replacement. The complete supporting structure, and operation thereof, is shownand described in the aforementioned Holbeck Patent No. 1,855,171. a

It will be seen from Figs. 1 and 5 that the feed side rotor element 3| is provided with a plurality of radially extending blades 33, illustrated as being three in number, although not necessarily so limited. The rotor 3| is mounted on shaft 33 with the blades 33 adjacent the intake 34 and act as suction fan blades in conjunction with fan 8, to draw material through intake 34 into the pulverizing zone, and to impart to the material a preliminary fracture.

By referring to Fig. 1,. it will be seen that the closure 21 when in the position shown provides a feed chamber 35 for the material dropped from the feed mechanism 2.

A partition 36 located in the casing 6 is provided with an opening 31 which registers with the openings 36 through the central portion of the fan side rotor element II. A removable cylindrical liner 39 is provided with circumferentially spaced projections 40 which extend transversely parallel to the axis of the shafts H and 30. The inner cylindrical wall of the liner 39 is provided with a multiplicity of transverse grooves to form a serrated inner cylindrical grinding wall 4| closely adjacent to which the radial grinding lugs 42 and 43 on the rotors travel along circumferential paths. Circular shoulders or supporting surfaces are provided on the annular flanges 44 and 45 for engagement by the radial projections 40 to center the liner or hold the same concentric with the axis of the shafts II and 30. The circumferentially distributed points of support at 46, 40 lessen the frictional contact to facilitate removal of the liner when desired, but nevertheless the frictional mounting for the liner is sufficient to hold the same in adjusted position against the partition 36 at its rear edge and against the inner edge of the closure 21 at its front edge, and to maintain the opening 46 on its lowermost side in communication with the tramp pocket 41 in the base 9 as shown in Fig. 1.

When the material, such as coal, to be pulverized falls to the bottom of the chamber 35, it will tend to accumulate therein, at least to a-certain extent, but the suction action of the fan blades 33, acting in conjunction with the fan 8 to draw the material into the pulverizing rotors, prevents any material amount of accumulation. Angle member 48, extending across the chamber 35, is designed to catch pieces of tramp iron, preventing the same from contacting with the rotor 3|. If, however, pieces of such tramp iron do come into contact with the rotor 3|, the larger pieces will be ejected by the rotor and remain in the bottom of the chamber 21. Smaller pieces of tramp material that may pass by the crusher lugs 43 will escape through the openings 49, 49, normally closed by the cover plates 50, 50.

Inasmuch as the rotor disc 3| is closed, the material to be pulverized must find its way peripherally of thedisc 3| between the grinding lugs 43 into the pulverizing zone. This action is greatly facilitated by the suction created by the fan blades 33 which act in conjunction with the fan 8 to draw the material from chamber 35 into the pulverizing zone and which preliminarily pulverize the material by impacting it against the grinding surface .of the liner 39. As the material is thus sucked, peripherally of the disc 3|, and between the grinding lugs 43 into the pulverizing zone, it is ground by impact against the leading sides of the lugs 43 and against the serrated cylindrical wall of the liner 39.

The sucking action above referred to is produced by cooperation of fan blades 33 and fan 8, the latter producing a current of air from the feed side of the disc 3|, which feed side carries the blades 33 into the hollow chamber between the rotor elements l2 and 3|. Whatever-material passes to the peripheral space surrounding the rotor |2 will be further crushed by impact against the radial spaced-apart lugs 5|, and by being thrown by the latter against the serrated cylindrical wall 4|.

While the suction of the air through the opening 31 tends to draw the crushed material through the peripheral space between the lugs 5| and the serrated wall 4| and radially to the left of the rotor l2 as'viewed in Fig. 1, this tendency is counteracted by the radial fins 53, 53

which are formed in radial continuation of spi- 4 der arms 54, 54 and by the auxiliary radial fins 55, 55, intermediate the fins 53, 53, as shown in Fig. 3. The faces of the fins 53 and 55 adjacent to the inner wall of the partition 36 are approximately in the same vertical plane which is closely adjacent to such inner wall. Consequent- 1y, an effective seal will be produced to prevent the passage of coarse material between the back of the rotor I2 and the adjacent wall of the partition 36.

The rotor 3| is provided with parallel spacedapart pulverizing lugs 56, which may be integral with the grinding-lugs 43,'but the spacing between the latter is shorter than the spacing between the grinding lugs 43. The rotor I2 is provided with similarly spaced pulverizing lugs 5|, which overlap the lugs 56 so as to leave only a small cylindrical space 58 between the paths of travel of the adjacent faces. It is preferred to arrange the. parallel lugs 5 6 and 5| so that the path of travel of the feed side rotor pulverizing lugs 56 will be of smaller diameter than the tendency of the material to pass between the back of the rotor l2 and the adjacent wall of the partition 36.

It should be particualrlyunderstood that the rotors when operating are driven at high speed in opposite directions and therefore the lugs 56.

and |-act as ejectors to prevent coarse particles from passing between the same into the hollow chamber 1, which action is further enhanced by the preliminary pulverization effected by the blades 33. The centrifugal forces acting on the material, moreover, are in opposition to the inward air current produced by the blades 33 and fan 8. The oppositely rotating rotors therefore act to separate automatically the fine particles from the coarse, the coarse particles being continually thrown outwardly against the serrated wall 4| while only the finest or pulverized material'flows with the air through the opening 31 into the fan chamber 59.

The coarser particles continue to be pulverized by impact and attrition around the circumferences of the rotors until they are so fine that the centrifugal forces of the rotors no longer eject them outwardly. Only the extremely fine material is pulled through the 'ring space 58 by the air current produced by the fan 8 into the fan chamber 53. Pulverization is completed in the ring space 53 or between the overlapping adjacent faces of the pulverizing lugs 56 and 5| because actual tests show that the maximum wear takes place at such adjacent faces, and at the leading corners as illustrated at 60. 60 in Fig. 2, the direction of rotation of the rotor I2 being in the direction of the arrow. The same is true with respect to the wear on the lugs 56 of the feed side rotor 3 In brder to drive the feeding mechanism 2 from the shaft H, a pulley 6| on the latter is connected by a. belt 62 to a pulley 63 which is loosely mounted on the shaft 64 of the speed reducer 65. The shaft 66 of the latter is connected to a disc 61. On the shaft l4 of the feed roll I3 is mounted an arm 68 which is pivotally connected to a link 69. The latter is adjustably connected to a diametrical slot 10 on the disc 61. A clutch H, which is adapted to be spring released, is associated with the pulley 63, the

outer clutch element 12 being splined on the shaft 64. An electromagnet 13 mounted on the bracket 14 secured to the hopper I may be employed topull the rod 15 to the right as viewed in Fig. 1, thereby swinging the lever 16 on its pivot 11 to apply the clutch H and thus connect the shaft II to the speed reducer 65. The lower end of lever 16 is pivotally supported on bracket 18secured to the fan housing 6. A shipper I9 connects the lever I6 to the clutch element 12. Although the shaft rotates at a high speed, the speed reducer 65 will effect relatively very slow operation of the feeding mechanism 2.

On account ot-the high speed of rotation of the shaft II and the parts connected thereto including the armature of the motor l0, there will be considerable momentum tending to continue motor I has been cut on. It is desirable to stop the feeding mechanism as soon as the current to the motor in is shut off, and therefore the electromagnet I3 is arranged to be deenergized so that the clutch II will .be released and the. feed mechanism 2 stopped as soon as the motor current is interrupted.

Where the present apparatus is installed in connection with a'heating system, or where the installation is such that the quantity of air mixed with'the pulverized material is of importance, in order to assure an ample supply of air, there is preferably provided an air intake opening at '66 regulated by a shutter 8| operable by the handle 82. The mixture of air and pulverized material, such as coal, is forced by the blower fan 8 into any suitable conduit or receiver, not shown.

Reverting to the operation of the pulverizer comprising the oppositely rotating elements l2 and 3|, it should'be noted that the construction is such as to maintain the same entirely open at all times for free and uniform flow of air during pulverization. The coal or other material to be pulverized is fed gradually into the chamber 35, whence it passes into engagement with the blades 33 on the feed side rotor 3|. These blades 33, rotating at high speed, project the entering material against the surface 4| where it is initially pulverized. It will be further observed that the blades 33 and the grindingvlugs 43 are arranged in staggered relation relatively to each other, so that the material, as

it is initially pulverized and fed into the space between'the grinding lugs 43 and grinding surface 4|, through the action of the blades 33, will be picked up by lugs 43 and further pulverized before passing into the ring space 58. The feed side lugs 43 and 56 keep the material from accumulating at any portion of the wall 4| of the liner 39, so as to permit free passage of the air and coal into the ring space 58 between the lugs 56 and 5|. The outer ends of the lugs 43 are closely adjacent the serrated wall 4| and this, together with the initial pulverization produced by the action of the blades 33, substantially advances the pulverizing action before the material reaches the oppositely moving lugs 56 and 5|.

The radially projecting lugs 5| closely adjacent the serrated wall 4| act to keep the space surounding the lugs 56 open for free access of air through these lugs into the chamber 1 between the rotor elements. Air may pass through the spaces between the lugs 51 as well as between the spaces between the lugs 56 into the chamber 1, drawing the finely pulverized material therewith, coarse particles being ejected outwardly against the wall 4|. When the particles enter the space 58 they are pulverized by impact and attrition effected by the rapidly rotating lugs 56 and 5| passing each other in opposite directions.

The radial ribs or fins 53, 55 in addition to strengthening the fan side rotor element l2, also seal the space between the back of the rotor element and the adjacent wall of the partition 36 against the passage of any coarse particles through such space to the opening 31. Such ribs or fins set up a fan action counteracting the tendency of the fan 3 to produce a currentv of of parts without departing from the spirit and scope of the invention as defined by the claim hereto appended, and I wish therefore not to be restricted to the precise construction herein disclosed.

Having thus described and shown an embodiment of my invention, what I desire to secure by Letters Patent of the United States is:

A pulverizing apparatus comprising the combination with a casing, of two overlapping concentric rotor elements comprising spaced-apart series of pulverizing lugs parallel to the axis of rotation of the said rotor elements, separate motors one of which is connected to each of said rotor elements to rotate the same in opposite directions, means aflording an entry opening into the said casing for the material to be pulverized, a plurality of blades on the rotor element adjacent the said entry opening, and adapted to engage material passing into the entry opening and to project the said material against the casing for effecting preliminary fracture of the said material, peripheral spaced-apart preliminary grinding devices on the said rotor element adjacent to the said entry opening, a cylindrical grinding wall adjacent to the path of the said preliminary grinding devices, the rotor element adjacent the entry opening comprising a closing disk carrying the said blades, the blades producing a fan action impelling the preliminarily fractured material to rotate peripherally of the lastnamed rotor element to the pulverizing lugs, spaced-apart peripheral grinding devices adjacent the grinding wall and mounted on the rotor element spaced from the entry opening, the lastnamed rotor element having an exit opening in the central portion thereof, the said grinding de-' vices being positioned intermediate the blades and said exit opening so as to act upon the ma.- terial as it is projected between the said device and the grinding wall by the said blades.

RICHARD D. NICHOLS.

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