US2149571A - Hammer mill - Google Patents

Description

W. A. BATTEY March 7, 1939.

HAMMER MILL 3 Sheets-Sheet l Filed Oct. 30, 1956 Y INVE TOR Q.

W. A. BATTEY March 7, 1939.

HAMMER M I LL Filed OGL 30, 1936 3 Sheets-Sheet 2 /V/r/r lNvEN OR www 6,?.

BY LMI E y? R ,NWO

W. A. BATTEY arch 7, 1939.

HAMMER MILL Filed Oct. 30, 1956 3 Sheets-Sheet 3 INVEN R K WM Q. BY

@WM Pw@ ATTORNEYS Patented Mar. 7, 1939 .UNITED STATES PATENT OFFICE HAMMER MILL William A. Battey, Haverford, Pa., assignor to Pennsylvania Crusher Company, Philadelphia, Pa., a corporation of New York Application October 30, 1936, Serial No. 108,317

Claims. (Cl. 83-11) This invention relates to crushing equipment, the hammer circle about vthe duplex cage. A and more particularly to that class of equipment feed chute or hopper 23, through which material known as hammermills, adapted for crushing or is fed into the chamber, is positioned centrally at breaking coal, stone and the like. the top between breaker plates II and I2 which The principal objects of this invention are to slope upwardly to meet the feed chute in a man- 5 secure greater capacity or fineness of crushing, ner to form the upper portion of the primary or both, and lower maintenance and power costs. zone.

Related objects are to increase the, length of The breaker plate I3 is pivoted by a mechanism service of the crushing elements, to reduce the comprising a handwheel 29 mounted on a shaft 10 frequency of replacements, and to provide uni- 30 to which is attached a worm 3|. The worm 10 formity of Wear, automatic resharpening of engages with a wormwheel 32 mounted in pivot crushing members and ability to wear out the pin I5 to swing the breaker plate' I3 when the hammers without removal from the mill for handwheel is turned. A similar handwheel turning. mechanism is provided for lthe opposite breaker There have previously been in use hammerplate I4. It is intended that during operation of 15 mills comprising a rotating' hammer system the machine one of the pivoted breaker plates withina rigid or unsymmetrically adjustable pershall be closed and the other open. This relaforate cage, but these hammermills have been tionship is shown in Fig. 2 wherein the combinasubject to the disadvantages of uneven wear of tion breaker plate and tramp iron deflecto-r I3 is crushing members, resulting in widely varying shown closed down and plate I4 raised outwardly 20 cage and hammer circle concentricity, entailing to form a tramp iron deiiector 33 which with a wide variations in size and character of product. bottom plate 34 and the outer wall of the frame These disadvantages are overcome and the fOIm a tramp irOIl Docket. The PiVO-t Operating above objects attained by means of this invenmechanisms for plates I3 and I4 are mechanition by a symmetrical construction of the prlcally interconnected by a sprocket and chain 25 mary and secondary crushing chambers and mechanism 9 to maintain the relationship. Inhammer mechanism, and the reversible operation stead of the interconnecting mechanism 9, there thereof. The crushing chambers are arranged may be used if desired, an individual handwheel relative to the hammers so as to perform both mechanism for plate I4 such as is shown for primary and secondary reductions of the mateplate I3. 30 rial and means is provided for maintaining ac- The cages or screening sections are formedl by curate concentricity of cage and hammer circles. a frame of arcuate members shown at 20 and 2|,

The invention will be better understood from to which are fastened longitudinally extending the following detailed description of a specific screen bars or plates 22 providing screening 35 embodiment with reference to the accompanying spaces therebetween. The two cages o-r screen- 35 drawings of which: ing sections are supported at the' bottom on the Fig. 1 is a side sectional View, taken at line I--I, pivot shaft I9 and at their upper ends by racks of Fig. 2, of a machine embodying the invention; 35 and 36 attached respectively to pivot pins 31 Fig. 2 is a section of a front elevation taken at and 38. The racks 35 and 36 are raised or low- I40 line 2-2 of Fig. l; ered by a suitable mechanism operated by hand- 40 Fig. 3 illustrates a detail of an adjustable Wheels 39 and' 40, respectively. For illustration, screening cage; the mechanism associated with rack 35 will be Fig. 4 is an elevation view in section, showing described: The handwheel 39 is keyed to a handle the essential elements of another machine emshaft 4I having near its inner end a worm 42.

bodying the invention; and The worm engages a wormwheel 43 keyed to a 45 Fig. 5 is a top view, partially in section, of the shaft 44 on which is also keyed a rack pinion 45 machine of Fig.'4. which raises or lowers the rack. In this way the The machine of Figs. 1 and 2 comprises a supcages or screening sections can be pivoted inporting and enclosing frame IIl which is suitwardly or outwardly on pivot shaft I 9, to mainably webbed to provide strength and rigidity. tain the desired concentricity between the cage Within the upper portion of the frame I0 is the and hammer circles. primary crushing chamber formed by fixed solid There is also provided a screw or hydraulic breaker plates I I andf I2 near the top, pivoted jack mechanism for raising or lowering the pivot solid breaker plates I3 and I4 hinged on pivot shaft I9. 'I'he bearings for shaft I9 rest at each pins I5 and I6, respectively, and that portion of end on a stud 5I threaded through a hollow bush- 55 ing 50 xed within a wormwheel 52 which is mounted over the stud and rested on a boss 49. The wormwheel 52 associated with each stud 5I is turned by a handwheel 53 which operates through a shaft 54 and worm 55 on a wormwheel 56 keyed to a shaft-51, to which is also keyed a pair of worms 58. The two worms 58 engage the wormwheels 52 respectively; thereby turning bushings 50, which raises or lowers the pivot shaft I9;

To close oif the space between the upper ends of screening sections I'I and I8 and the tramp iron pocket or pivoted breaker plate, and also to hold plates I3 and I4 rmly in position when they are closed down,- there are provided members 66 and 41 pivoted at the ends of the sections I1 and I8. These members rest against plates 48 and 34, respectively; and when a plate I3 or I8 is closed down the corresponding member 46 or 41 is wedged between the plate and the member, as shown at member 46.

The machine is provided with a rotor containing a hammer mechanism as follows: A shaft 24, mounted at each end in bearings, extends through the chamber, as shown; and on this shaft, within the chamber, are placed a number of discs 25 regularly spaced apart by collars 26. These discs and collars are secured to the shaft in any suitable manner. of rods 21 (10 in this case) extend longitudinally through suitable holes in the discs 25 at regularly spaced intervals within the circumference of these discs and are fastened in place in a suitable manner. Hammers 28 are pivoted on the rods 21 within the spaces between the adjacent discs 25. I'he position of the hammer mechanism is such as to divide the crushing chamber into a relatively large primary crushing zone between the hammers and breaker plates above the perforate screen sections, and a secondary crushing zone of relatively small cross sections between the hammers and the screens. The rotor is located substantially concentric with respect to the screening sections and the hammers pass close to the screens.

The cages or screening sections can be adjusted relative to the hammers by operation of the handwheels 39, 48 and 53. To move the screening member closer to the hammers, pivot shaft I9 may be moved upward by handwhe'el 53 and the upper portions of the screening members are pushed inward by handwheels 39 and 40 to maintain accurately the desired clearanceV between the two circles.

The arrangement of the racks 35 and 36 operated by handwheels 39 and 40 may be modied, if desired. An alternative arrangement is shown in Fig. 3 which shows the pivot pins 31 and 38 supported respectively in slots 10 and 1I of supporting members 12 and 13, attached to the frame. When the stud I is raised as, for example, by the same mechanism as in Fig. 1, the pins 31 and 38 are forced to slide upwardly and inwardly in their supporting slots. The arrangement of the pins and slots may, if desired, be reversed; that is, the slots placed in the screen.- ing members and the pins on the frame members.

The machine of Figs. 4 and 5 is a modification of the invention useful for pulverizing material, in which the pulverized material is cleared from the machine by wind sweeping. Imperforate members 88 and 8l are provided within the frame 19 in place of the perforate screening members 20 and 2| of Fig. 2. These imperforate members are preferably provided with longi-A A number f tudinally extending corrugations 82. but the corrugations may, if desired, be omitted. The breaker plates 83 and 94 are perforated with holes 85 large enough for the finely pulverized material to pass through. Conduits 86 and 81 extend from the sides of the frame, or casing, just above the tramp iron pockets to an air box 88, adjoining the casing, which communicates with a fan casing 91 containing a fan 89 driven from the hammer shaft. These conduits can be opened or closed asdesired by valves 9| and 92, respectively. 'Ihe air exhausted by the fan is passed through a conduit 93 to a cyclone or other means for separating and collecting the pulverized material in a well-known manner, as indicated in Fig. 5. An air intake 94 is provided at each end of the hopper and is preferably provided with a damper device such as the rotary disc damper 95 to regulate the amount of air drawn into the machine.

In operation of the machine of Figs. 1 and 2, the hammer shaft 24 is rotated in either direction by an external source of power (not shown) When the shaft is to be rotated counter clockwise, as shown by the arrow A in Fig. 2, pivoted plate I3 is placed in the closed position and the plate I4 in the open position, as shown in Fig. 2, and for rotation in the clockwise direction plate I4 is closed and plate I3 is opened. The rotation of the hammer shaft causes the hammers 28 to throw out radially by centrifugal force; and the hammers strike masses of the material which have entered the relatively large primary crushing zone from the overhead feed chute, impacting them by direct blows against the breaker plates for a primary reduction. The material is then driven into the relatively narrow secondary crushing zone formed between the hammers and cages or screen sections where it is reduced to a higher degree of neness by impact and crushing pressure against the screen bar edges, or screen plate perforations. Tramp iron is centrifugally thrown into pocket 33 in the case of counter clockwise rotation, and into the pocket at plate I3 in the case of clockwise rotation. These pockets are emptied from time to time.

The breaking action produces continuous wear on the hammers and also at the screen bars, and when the hammers are rotated in only one direction the wear occurs principally at one side of the hammers and bars. The useful life of the hammers and bars can therefore be greatly prolonged by frequently reversing the direction of rotation to distribute the wear over both sides thereof. The reversibility is permitted by the symmetrical construction of the hammers and chamber and the location of the feed Chute centrally at the top of the primary crushing chamber, for by reason of this construction the breaking action of the material is the same for either direction of rotation.

Those pieces of material which are. broken small enough to pass through the spaces between the bars pass into the chamber 6I between the cage and the frame I0, from where they drop into Aa suitable. conveyor or receptacle. Those pieces of the material which are still too large to' pass through the screen remain in the chamber and are impacted and crushed by the hamrners against the nearer edges 60' of the screen bars (in the case of counter clockwise rotation).

To be most effective in producing a clean breaking these edges 60 should be maintained as sharp as possible. The effect of the continued impacts against these edges, however, is to wear them rounded or dull.

During the impacting and crushing action much of the material is driven tangentially over the surfaces of the screen bars, thus wearing down the bars and sharpening the further edges '52 of the bars at the same time that the near edges 60 are being dulled. A similar action occurs at the hammers, of which the nearer edges 65 are worn rounded by the impacts, the ends 63 are worn down by the tangential action and the further edges 64 are sharpened.

After the machine has been run in the counterclockwise direction for some time and the edges 60 and 65 have become dulled, the machine may then be rotated in the opposite direction to take advantage of the sharpened edges 52 and 64. During this direction of rotation, the edges 5I) and 65 become resharpened in the manner described above. Thus the breaking edges of the machine are self-sharpening by the tangential action of the material resulting from the close proximity of the hammers to the screen bars, or plates, and reversing the direction of rotation.

The machine described herein by reason of its symmetrical construction and overhead feed chute is adapted to reversible operation. The reversible operation introduces the advantages of wear distribution and self-sharpening, resulting in increased service, reduced frequency of replacement of hammers and screen bars and lower maintenance cost.

By this invention there are combined in one unit primary and secondary crushing zones, providing a double reduction. The primary reduction is promoted by the dropping of the large entering masses directly into the path of the hammers where they are struck by the faces and fractured and impacted through the relatively large primary crushing zone against the imperforate breaker plates. This increases primary impact crushing between the hammer and overhanging breaker plates, thereby reducing the power requirement and the wear on hammers and cage bars. The reduction in the primary zone enables the material to enter the relatively narrow tapering space of the secondary crushing zone between the hammers and the perforate or imperforate cage members. In this secondary zone the material is reduced to the desired fine size by the action between the rapidly rotating hammers and cage bar edges or corrugations. This arrangement for combined primary and secondary reductions results in greater output of a given neness or in increased neness with the same output, as compared with prior crushing machines of the hammer type, with inherently smaller cage area.

The use of the duplex cage increases the cage area which inherently affords greater output and/or neness of crushing. Although the cages are shown as occupying somewhat less than a semicircle they can if desired be extended well above the center line of the machine to occupy more than a semicircle.

The mechanism for adjusting the height of shaft I9 and for moving in the upper ends of the screening sections provides a ready means for adjusting the duplex cage relative to the hammers, which adjustment determines the size and uniformity of the product. As the, hammers and/or screen bars or corrugations gradually wear down, increasing the space between them or making the cages eccentric with reference to the hammers or both, the cage position can be adjusted in this manner to compensate for the wear and restore the desired concentricity, and uniformity of product.

'I'he construction also provides combination breaker plates and tramp iron deflectors, which permit tramp iron pocketsgto be opened on the side opposite that on which the primary reduction is being made.

'I'he operation of the wind swept machine of Figs. 4 and 5 is very similar to that of the ma' chine shown in Figs. 1 and 2, the principal difference being the means for expelling the pulverized material. Material to be pulverized is fed in through the feed hopper and reduced by the hammers as in the machine in Figs. 1 and 2. The imperforate sections 80 and 8l act like the screening sections of Figs. 1 and 2 except that no material can be passed through, but instead the pulverized material is carried out of the machine by the wind sweeping produced by the fan. For this purpose the fan is rotated in the direction to exhaust the air from` the fan casing 91 in'the direction shown by the arrows. Consequently the incoming air drawn into the mill through the intake openings 94 becomes laden with the pulverized material as it passes through the primary and secondary reduction zones and is then exhausted through the perforations in the deector member over the open tramp iron pocket and through the conduit leading to the air box and fan. From the fan it is sent to the separator which collects the pulverized material. To permit this wind sweeping operation the valve 92 in the conduit above the trap iron pocket which is open must be opened and the other valve A9| may beclosed.

The references to abrasive action are intended to include impact, shearing, crushing and other effects of forcible contact between the hammers, the screen members and the material whereby the hammers and screen members are worn away or sharpened.

A reversible hammermill as covered by thev claims is a mill in which the hammers may be rotated in either direction, and the crushing chamber and associated crushing instrumentalities are symmetrically arranged at both sides of the Ahammer system to provide substantially similar crushing action regardless of the direction of rotation of the hammers.

I claim:

1. A hammermill comprising a reversible rotatable hammer system, a crushing chamber symmetrical with said system, receptacles for tramp material symmetrically located at opposite sides of the upper part of the chamber and breaker plates mounted adjacent the receptacles and adjustable to form closures for said receptacles or to leave said receptacles in open operative position, the construction and arrangement being such that either breaker plate may be located in closed position with the other breaker plate in open position in accordance with the direction of rotation of the hammer system.

2. A hammermill comprising a crushing chamber and a rotating hammer system in the chamber, said chamberl including screen members adjacent the hammer path, a pivotal connection between adjacent margins of the screen members, means for adjusting said connection radially relative to the hammer system, and means for adjusting the opposite margins of the screen membersv about said connection.

3. A hammermill comprising a crushing chamber and a rotating hammer system in the chamber, said chamber including a pair of oppositely located screening members, a single means for adjusting simultaneously the lower margins of the effective faces of the screening members radially toward the axis of the hammer system, and separate means for adjusting the upper margins of the screening members radially toward said axis.

4. A reversible hammermiil comprising a housing, a crushing chamber within the housing and having a substantially horizontal axis, a system of hammers in the chamber rotated as a unit around a substantially horizontal axis, means for rotating the hammer system at impact-crushing speed, a feed inlet located centrally over the hammer system, a separate breaker plate at one side of the inlet mounted in the housing and spaced from the hammer path by a distance greater than the diameter of the largest piece of material to be crushed, positioned to intercept material from the inlet impacted by the ham- -mers when rotated in one direction, a separate breaker plate at the other side of the inlet mounted in the housing and similarly spaced from the hammer path and positioned to intercept material from the inlet impacted by the hammers when rotated in the other direction, and a discharge outlet for crushed material.

5. A reversible hammermiil comprising a housing, a crushing chamber within the housing and having a substantially horizontal axis, a system of swinging hammers in the chamber maintained in operative position by centrifugal force and rotated as a unit around a substantially horizontal axis, a primary crushing compartment in the chamber surrounding the upper portion of the hammer system and located above the level of the axis of the system, an inlet in the compartment located over the hammer system, a separate breaker plate mounted in the housing at one side of the inlet in horizontal alignment with the upper part of the hammer path and positioned to intercept material from the inlet impacted by the hammers when rotated in one direction, a separate breaker plate mounted in the housing at the opposite side of the inlet positioned to intercept material from the inlet impacted by the hammers when rotated in the other direction, and an outlet for crushed material.

6. A reversible hammermiil comprising a housing, a crushing chamber, a system of swinging hammers in the chamber maintained in operative position by centrifugal force and rotated as a unit, a feed inlet located centrally over the hammer system, a separate breaker'plate at one side of the inlet mounted in the housing and spaced from the hammer path by a distance greater than the diameter ofthe largest piece of material to be crushed and positioned to intercept material from the inlet impacted by the hammers when rotated in one direction, a separate breaker plate at the other side of the inlet mounted in the housing, similarly spaced from the hammer path and positioned to intercept material from the inlet impacted by the hammers when rotated in the other direction, and a screen located below the hammer system having edges extending transversely to the direction of travel of the hammers and positioned to support oversize in the hammer path.

7. A reversible hammermill comprising a housing, a crushing chamber, a system of swinging hammers in the chamber maintained in operative position by centrifugal force and rotated as a unit, a feed inlet located centrally over the hammer system, a separate breaker plate at one side of the inlet mounted in the housing, spaced from the hammer path by a distance greater than the diameter of the largest piece of material to be crushed and positioned to intercept material from the inlet impacted by the hammers when rotated in one direction, a separate breaker plate at the other side of the inlet mounted in the housing, similarly spaced from the hammer path and positioned to intercept material from the inlet impacted by the hammers when rotated in the other direction, a screen located below the hammer system having edges extending transversely to the direction of travel of the hammers and positioned to support oversize' in the hammer path, and means for radially adjusting the screen toward the axis of rotation of the hammer system to compensate for wear.

8. A hammermiil comprising a crushing chamber, a rotating hammer system in the chamber, a pair of contiguous screen sections adjacent to the path of the hammers, pivot means located parallel to the axis of the hammer system connecting the adjacent margins of the screen sections to form a hinge joint, and means for adjusting the pivotal means radially relative to the hammer system Xwhile maintaining said means parallel to the axis of the system.

9. A reversible hammermill comprising a housing, a crushing chamber within the housing and having a substantially horizontal axis, said crushing chamber having its' opposite sides symmetrical with relation to a longitudinal vertical plane containing the chamber axis, a system of pivoted hammers in the chamber rotated as a unit around a substantially horizontal axis paralle] with the axis of said chamber, inlet means opening through the upper portion of the chamber wall and symmetrically arranged with reference to said vertical plane containing said axis fo-r introducing the material to be crushed into the chamber over said hammer system, means for rotating the hammer system at impact crushing speed in either direction to initially fracture the material being crushed, a breaker plate forming a wall of said chamber at one side of said lplane and mounted in the housing and spaced from the hammer path by a distance greater than the diameter of the largest piece of material to be crushed and acting to intercept material from the feed means impacted by the hammers when rotated in one direction, another breaker plate forming an opposite wall of said chamber and symmetrically mounted at the other side of said plane with respect to the first mentioned breaker plate and similarly spaced from the hammer nath and acting to intercept material from the feed means yimpacted by the hammers when rotated in the other direction, and a discharge outlet for the crushed material through the lowerportion of the chamber below both of said breaker plates.

10. A reversible hammermiil as set forth in claim 9 having a primary crushing zone in which the separate symmetrical breaker plates are mounted and a secondary crushing zone having crushing screens provided with discharge opening edges generally parallel to said axis of the hammer system and located symmetrically adjacent the lower portion of the hammer path in position to provide abrasiveaction between the hammers, bars and interposed material.

WILLIAM A. BATI'EY.

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