US3047243A

US3047243A - Disintegrating mill

Info

Publication number: US3047243A
Application number: US841849A
Authority: US
Inventors: Alfred F Meger; Arthur L Hawthorne
Original assignee: J M J IND Inc
Current assignee: J M J IND Inc
Priority date: 1959-09-23
Filing date: 1959-09-23
Publication date: 1962-07-31
Anticipated expiration: 1979-07-31
Also published as: DE1184075B

Description

July 31, 1962 A. F. MEGER ETAL DISINTEGRATING MILL 2 Sheets-Sheet 1 Filed Sept. 23, 1959 INVENTORS F. ME GE R ALFRED BY ARTHUR L. HAWTHORNE ON MS my 3 21 ATTORNEYSp July 31, 1962 A. F. MEGER ETAL DISINTEGRATING MILL 2 Sheets-Sheet 2 Filed Sept. 25, 1959 INVENTORS ALFRED E MEGER BY ARTHUR L. HAWTHORNE M ATTORNEYS United States Patent 3,047,243 DISINTEGRATING MILL Alfred F. Meger and Arthur L. Hawthorne, St. Clairsville, Ohio, assignors to J.M.J. Industries, Inc., Belleville, 111., a corporation of Illinois Filed Sept. 23, 1959, Ser. No. 841,849 1 Claim. (Cl. 241-188) The present invention relates to a new and novel disintegrating mill, and more particularly to the type generaly designated an internally fed impact cage mill or crusher.

Disintegrating mills are generally employed :for reducing solid granular material to a finer particle size, the treated material being stone, ore, or other similar types of materials. The material is forced to travel outwardly by centrifugal force due to rotation of the cages of the mill, and as the particles of material move radially outwardly, they are struck by suitable impact means formed on the cages which shatters or disintegrates the material to reduce it to smaller size.

It has been found that the most etlicient type of cage mill is that which employs a pair of rotors which rotate in opposite directions. Each of these rotors may be provided with annular rows of impact means which are so mounted as to be in alternate relationship with the rows n the other rotor. This arrangement has proved to be superior to the old type of cage mill or crusher wherein alternating rows are provided with stationary impact means which cooperate with rotating impact means mounted on a single rotor. The multiple type cage mills of the type employed in the present invention provide almost double the impact force possible with a single cage mill which operates at the same peripheral velocity.

Prior art cage mills of the type according to the present invention have incorporated structures which have proved to be disadvantageous for a number of reasons. The structure and disadvantages of such prior art structures have produced excessive wear and have required a large amount of power to operate. In addition, all particles treated by the apparatus have not received uniform or maximum impact forces during treatment. Furthermore, so-called by-pass leakage has been a major problem with such arrangements. Known structures have also created a problem in attempting to properly balance the cages since this is very difficult when attempting to repair or replace used parts of such structures. The present invention incorporates a novel arrangement wherein the outer end portions of the impact means of each rotor are connected with members which are mounted within groove means in the opposite rotor. The impact means of the two rotors are substantially coex tensive in a longitudinal direction such that the objectionable by-pass leakage present in prior art structures is substantially eliminated.

The present invention also incorporates a novel impact means including cage bars and wear members removably supported by the cage bars. The cage bars are so constructed and arranged as to occupy an area which does not interfere with the free passage of the treated particles in the designed paths of movement to properly process the particles. The wear members are provided with wear surfaces which are substantially flat and which are disposed in a plane within the range of a plane tilted 30 degrees forwardly in the direction of rotation of the rotor with respect to a radius of the rotor to a plane tilted 15 degrees rearwardly in the direction of rotation of the rotor with respect to a radius of the rotor.

The removable wear members provide a means whereby wear surfaces may be quickly and easily replaced, and furthermore the wear members are of substantially uniform construction such that when they are mounted in place on the rotors, there is no serious problem as to balancing the rotor since the rotor itself can be effectively balanced at the factory, and the uniform wear members may be replaced when desired in the field.

In order to insure that the particles passing radially outwardly from one row of impact means to the next row are enabled to travel in the proper lines so as to uniformly treat the particles, an arrangement is provided wherein the radially inward trailing edge of the wear members may be cut away at a predetermined angle. The dimension of the radially inward surface of the wear member may also be such that it is less than one half the total circumferential dimension of the wear member and its associated cage bar to obtain the desired result.

An additional important feature of the present invention is an arrangement whereby the air problem encountered in this type of disintegrating operation is solved. Air intake must be kept to a minimum during operation of this type of apparatus to prevent excessive pressures from being built up inside the housing thereof since high pressures therein tend to force dust through the seals and out of the discharge opening of the housing creating a safety, health, and maintenance problem. In order to prevent such excessive pressure in the present invention, a bypass air passage is provided which vents the outer periphery of the rotors to the input feed chute of the apparatus thereby creating a by-pass path for the air which is pumped by the rotary action of the rotors.

A further novel and efficient method of preventing air pressure from building up at the seal between the rotating drive shaft and the casing of the apparatus is to provide a set of radially extending vanes which are utilized to create an air pumping action and a partial vacuum at this sealing area. This further insures that excessive air pressures will not be developed at the seal between the shaft and the casing which has proved to be a serious problem in prior art structures of this type.

An object of the present invention is to provide a new and novel disintegrating mill which provides a uniform and maximum impact force on the particles of material processed thereby.

Another object of the invention is the provision of a disintegrating mill which reduces the wear rate of the components thereof.

Yet another object of the invention is to provide a disintegrating mill wherein the power requirements are less than those of the prior art mills.

A still further object of the invention is the provision of a disintegrating mill which eliminates so-called bypass leakage.

Still another object of the invention is to provide a disintegrating mill which may be readily balanced when repairing or replacing worn components thereof and which incorporates an arrangement for easily replacing such worn components.

Another object of the invention is to reduce the air intake of the apparatus to a minimum and to relieve pressure built up within the housing thereof.

Other objects and many attendant advantages of the FIG. 6 illustrates one form of impact means according to the present invention;

FIG. 7 illustrates a modified form of impact according to the present invention;

FIG. 8 illustrates a modified form of impact according to the present invention;

FIG. 9 illustrates a modified form of impact according to the present invention;

FIG. 10 illustrates a modified form of impact according to the present invention;

FIG. 11 illustrates a modified form of impact according to the present invention;

FIG. 12 illustrates a modified form of impact according to the present invention;

FIG. 13 illustrates a still further modified form of impact means according to the present invention;

FIG. 14 is a side view of the impact means shown in FIG. 13; and

FIG. 15 is a diagrammatic view illustrating certain critical angular relationships according to the present invention.

Referring now to the drawings wherein like reference characters designate corresponding parts throughout the several views, there is shown in FIG. 1 a disintegrating mill of the multiple cage type, a first rotor 10 being mounted for rotation in one direction and a second rotor 11 being mounted for rotation in the opposite direction. The material to be treated is fed into the central cham ber defined between the rotor and then passes outwardly to the periphery of the apparatus as it is processed. Rotor 10 includes a first row of impacting means indicated generally by reference numeral 15 and a second row of impacting means indicated generally by reference numeral 16, each of these rows being substantially annular and including a plurality of individual cage bars substantially circular in cross-sectional configuration. Rotor 11 includes rows 17 and 18 which are also substantially annular. It is noted that the rows of the two rotors alternate with one another as seen in FIG. 1 such that particles of the material to be treated will be forced to abruptly change direction as they pass from one row outwardly to another row.

Referring again to FIG. 1, undesirable by-pass leakage may be understood. In this view, particle A as indicated by the arrow is moving between rotor 11 and the row of impact means 15 such that the particle is by-passing the impact action of'this particular row. The particle B is shown as moving as indicated by the arrow between rotor 10 and row 18 of the impact means such that particle B by-passes the impact action of bar 18. Furthermore, particles such as C are free to strike the structural rings of the cage, these particles not being subjected to the impact action of bars 15 and in addition creating a wear problem since the structural ring is weakened and worn away by such action. This bypass leakage prevents all the particles from receiving uniform treatment and provides a finished product which is not of constant quality.

Referring now to FIGS. 2 and 3 of the drawings, the apparatus according to the present invention is illustrated including a hollow housing which is mounted upon a suitable support means 36. A feed chute 37 is sealed with respect to the housing and is in communication with the central portion of the interior of the housing. The upper end of feed chute 37 is sealed with respect to a storage bin 38 and is in communication with a lower open end 39 of the storage bin, the storage bin being adapted to hold a solid granular material or the like which is to be treated. A conventional feeder assembly 40 of the vibrating or stargate type is disposed at the upper end of the feed chute, the feeder assembly extending through a sealed or skirted opening 41 to minimize the amount of air which leaks into the mill.

An auxiliary by-pass chute 45 is connected between the outer periphery of the housing and an intermediate pormeans means means means means means tion of said chute, the by-pass chute serving as a means for relieving the pressure within the housing by permitting the pumped air to follow the path indicated by the dotted lines in FIG. 4, the air circulating in the direction as shown by the arrowheads. This arrangement minimizes the amount of air which enters the mill during operation and furthermore prevents the development of excessive pressures in the apparatus during operation.

As seen particularly in FIG. 3, the rotor mechanism is indicated generally by reference numeral 46, and is drivingly connected with a drive shaft 47. The drive shaft 47 extends within hollow casing 35 and is sealed with respect thereto by a conventional rotary seal 48 of well-known construction. A plurality of radially extending vanes 49 are mounted on the rotor mechanism adjacent the sealing means 48 and at the remote side of the rotor mechanism from the feed inlet to the casing. During rotation of the rotor mechanism, the vanes will produce an air flow in the direction of arrows A which tends to produce a suction adjacent the sealing area between the shaft 47 and sealing means 48. This suction produces a partial vacuum in this area and accordingly it effectively prevents air pressure from building up in this area.

Referring now to FIGS. 4 and 5 of the drawing, a pair of disc-

like rotors

50 and 51 are shown in operative relationship with respect to one another,

rotors

50 and 51 being connected to a source of power such that the two rotors are normally rotated in opposite directions in a well-known manner. As seen in FIG. 4, drive shaft 47 is of tubular construction and is drivingly connected with rotor 50. Shaft 47 is rotatably supported within housing 35 by means of a conventional bearing 54. A counter shaft 53 has one end portion thereof connected with rotor 51 and is rotatably journalled within tubular drive shaft 47 by means of a conventional bearing means 54'. It will be understood that the drive shaft 47 and counter shaft 53 will be rotatably driven in opposite directions in the conventional manner. The central space 52 defined between the rotors is adapted to receive the material to be processed which is fed into the apparatus through the feed chute 37.

Rotor 50 is provided with a first annular row of impact means indicated generally by reference numeral 55, the outer ends of impact means 55 being secured to an annular ring 56 which maintains the impact means in proper operative relationship to one another and which, of course, rotates with rotor 50. A second annular row of impact means indicated generally by reference numeral 57 is secured to rotor 50 radially outwardly of row 55, the outer ends of impact means 57 being connected to an annular ring 58.

Rotor 51 is provided with an annular groove 60 formed in the face thereof opposite rotor 50, annular ring 56 being disposed within groove 60 and spaced a small distance from the walls of the groove. Rotor 51 is of less diameter than rotor 50 such that when in assembled position, the outer periphery 61 of rotor 51 is spaced from the inner periphery of annular ring 58, the ring 58 being substantially radially aligned with rotor 51 as seen particularly in FIG. 4.

Rotor 51 is provided with a first annular row of impact means indicated generally by reference numeral 65, the outer ends of these impact means being connected to an annular ring 66. A second annular row of impact means 67 is secured to rotor 51 radially outwardly of row 65, the outer ends of impact means 67 being connected to an annular ring 68.

Rotor 50 is provided with an annular groove 70 within which ring 68 is disposed, the ring being spaced from the walls of the groove such that it is free to rotate therein. Rotor 50 is also provided with a disc-like cut-away portion 71 within which annular ring 66 is disposed, the ring being spaced from the walls of the cut-out portion such that the ring can freely rotate therein.

As seen especially in FIG. 4, the arrangement of the rotors and impact means according to the present invention may be observed which eliminates the undesirable by-pass leakage which occurs with such prior art constructions as shown in FIG. 1 of the drawings. As seen in FIG. 4, the impact means of the rotors are substantially radially aligned with one another, or in other words, they are substantially longitudinally coextensive and overlie one another such that each row of impact means has at least as great a longitudinal dimension as the row radially inwardly thereof whereby particles moving radially outwardly must come into direct contact with the succeeding row of impact means and cannot engage a structural member as occurs with particle C as shown in FIG. 1. It is apparent that the particles cannot by-pass the impact means in the arrangement shown in FIG. 4, and furthermore, cannot produce undesired wear upon the structural rings of the apparatus thereby providing a very compact and efficient arrangement for processing the desired material.

In order to obtain a uniform impact action on nearly all of the particles processed by the apparatus, so as to obtain a consistent product, and to obtain a maximum impact force and still cause the particles to be contacted only once by each row of impact means, the impact means of the present invention is of a special critical design.

Typical examples of arrangements in accordance with the design of the present invenition are shown in FIGS. 6-9, a thin plate being shown in each of these figures secured to and reinforced by a structural member abutting the trailing surface thereof. In FIG. 6, plate 90 is secured to a reinforcing member 91 having a substantially semi-circular cross-section. In FIG. 7, plate 92 is secured to a reinforcing member 93 of substantially triangular cross-section. In FIG. 8, a plate 94 is secured to a reinforcing member 95 having a substantially square crosssection. In FIG. 9, a plate 96 is secured to a reinforcing member 97 having a cross-sectional configuration similar to the cross-hatched area shown in FIG. 7. It is apparent that the constructions as shown in each of FIGS. 69 are such that the reinforcing members will not interfere with the paths of movement of the particles treated by the apparatus.

It will be noted that each of the

plates

90, 92, 94, and 96 as shown in FIGS. 6-9 are cut away at the radially inward trailing surface thereof to provide a sloping surface through which a dotted line passes. This dotted line represents the path of the particles passing closely adjacent the plate, the plate being cut away to accommodate such movement. This angle at which the plate is cut away may be defined as a relief angle since the plate is relieved at the trailing edge. This relief angle position required for minimum interference with the paths of the treated particles will vary due to various conditions such as the diameter of the rotors, the speed at which they are rotated and the types of material being processed. However, regardless of these different conditions, the optimum relief angle is considered to be one of approximately 135 degrees as seen in FIG. 15 with respect to a radius of the associated rotor. At any rate, the relief angle must be greater than a 90 degree angle as indicated in FIG. 15 with respect to a radius. According to the present invention the relief angle should range from greater than a 90 angle to substantially a -'l35 angle with respect to a radius. The ideal arrangement would be to provide a plate having a knife edge formed at the inner leading edge thereof such that the relief angle would be approximately 135 degrees and the relieved surface would define an angle of 45 degrees with the leading face of the plate as indicated in FIG. 15 of the drawings. This construction, however, is impractical, and a struturally practical configuration is illustrated in FIG. 11.

Referring now to FIG. 11, plate 100 is relieved to provide a surface 101 at the inner trailing edge thereof extending at an angle of substantially 135 degrees with respect to a radius, and a reinforcing member 102 is 6 welded as indicated at 103 to the trailing surface of plate 100.

A construction may also be provided as shown in FIG. 10 wherein a plate 105 is secured to a reinforcing member 106, and there would be no relief portion at the trailing edge of plate 105. This construction represents a compromise, and will provide satisfactory results providing that in this construction as well as in the construction shown in FIG. 13, the dimension X of the radially inward surface of the plate is less than one half the dimension Y which represents the total circumferential dimension of the plate and the reinforcing member combined.

An important improved results of the construction according to the present invention is the fact that the leading surfaces of the various plates will wear substantially evenly during operation of the apparatus so that the particles are uniformly treated throughout the useful life of the plates and furthermore regardless of the wear there will be no interference with the normal paths of travel of the treated particles.

Worn cage bars have usually been replaced in prior art structures by either replacing the entire cage or cages or replacing the individual bars. Another possible solution has been the building up of the worn area with weld metal or hard facing metal or some combination thereof. This, of course, is an expensive and time-consuming operation which is eliminated according to the present invention. It is a particular object of this invention to provide an arrangement whereby the impact means includes a replaceable component. This is accomplished preferably by providing an arrangement wherein the aforementioned structural members are permanently secured between an associated rotor and one of the annular ring members whereas the relatively thin plates may comprise wear members which are removably secured to and supported by the reinforcing structural members such that the wear members may be readily replaced at will. The manner in which the wear members are secured to the cage bars or structural members is relatively unimportant as long as the wear members can be readily removed when desired. For example, the wear members may be secured in place by bolting, wedging, welding, or by the use of adhesives or the like.

The utilization of such replaceable wear sections which are uniform in weight and uniformly positioned and attached to each cage bar is additionally important in balancing the cage construction. It is evident that unbalance of the cages will produce an undue load on the supporting members and bearings. Such unbalance is not likely to occur with the construction of the present invention since when the wear members are replaced, they are replaced in such a manner as to provide an automatically balanced construction. As a result, the disintegrating mill of the present invention requires practically no additional balancing procedures after repairs have been conducted in the form of replacing worn or damaged impact means.

Referring now to FIG. 12, one form of construction employing a removable wear member is illustrated. In this construction, a conventional angle member 105' is employed as the reinforcing member and is, of course, secured between the associated rotor and one of the annular ring members. The replaceable wear member 106 comprises a relatively thin plate similar to those previously described, this plate having a threaded opening 107 formed in the trailing surface thereof. Leg 108 of angle member 105' is provided with an opening 109 therethrough, a threaded stud 110 extending through opening 109 and being threaded into opening 107. A nut 111 is threaded on the outer end of stud 110 and in conjunction with a washer 1.12 serves to clamp the plate 106' to the angle member 105'. It is evident that the wearing member 106' may be readily removed whenever desired.

An additional modification is shown in FIGS. 13 and 14 wherein a structural member is provided having a pair of spaced openings 121 formed therein. The removable wear member comprises a relatively thin plate 125 having a pair of pins 126 formed on the trailing surface thereof which extend within openings 121 formed in member 120. A key 127 is provided for maintaining the struc ture in operative relationship as shown until it is desired to remove the Wear member.

While the disposition of the leading surfaces of the impact means has been disclosed as being substantially radial heretofore, it has been found that this angle may be varied within certain critical limitations in order to obtain the desired results. Although the radial disposition is considered preferable, it has been found that the impact surfaces operate satisfactorily within the limits as illustrated in FIG. 15. The range within which the impact surface operates satisfactorily is between a forward tilt of the impact surface of 30 degrees with respect to a radius to a rearward tilt of the impact surface of degrees with respect to a radius. If the leading surface is tilted forwardly more than degrees, a great reduction in efficiency is realized, and if the leading surface of the impact means is tilted rearwardly more than 15 degrees from the radius, bad wear and operating characteristics result. It should be realized that the expressions forwardly and rearwardly as used above are with reference to the direction of rotation of the associated rotor.

It will be noted from an inspection of the various figures and as particularly in FIGS. 6-9, that the trailing edges of the various bars lie in planes, and that in each instance the bars are dimensioned and configured such that no portion of the bar extends radially inwardly of a radially adjacent point lying in a plane passing through the trailing edge of the associated wear member. This construction ensures that any treated particle which passes by the trailing edge of the wear member will not intersect a portion of the associated bar.

It will also be noted that the innermost edge of each of the wear members has a circumferential dimension which is substantially less than the circumferential dimension of the main body portion of the wear member, and as will be noted from an inspection of FIGS. 6-9, 11 and 14, the circumferential dimension of the innermost edge of each of the wear members is approximately one half the circumferential dimension of the main body portion of the wear member.

It is apparent from the foregoing that there is provided a new and novel disintegrating mill which provides a maximum and uniform impact force on the particles of material processed thereby. The wear rate of the impact means is substantially reduced with this construction, and in addition, the power required to operate the apparatus is also substantially reduced. This construction in addition eliminates the by-pass leakage which occurs with prior art constructions and prevents excessive wear on the structural rings thereof. Removable wear members are provided such that worn or damaged impact means may be quickly and easily replaced and in addition the wear members are of uniform size and are uniformly mounted so as to facilitate balancing of the cage structure. An arrangement is also provided which reduces the air intake within the structure to a minimum and which prevents the build-up of excess pressure within the housing of the apparatus.

As this invention may be embodied in several forms Without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, and since the scope of the invention is defined by the appended claim, all changes that fall within the metes and bounds of the claim or that form their functional as well as conjointly cooperative equivalents are therefore intended to be embraced by the claim.

We claim:

A disintegrating mill comprising at least a pair of can centrically disposed and spaced ring-like rotors, each of said rotors including substantially flat opposed facing ringlike sides with a pair of radially spaced annular rows of laterally disposed impact means fixedly supported between the said sides, the rows of impact means of one rotor alternating with the rows of impact means of the other rotor, each of said impact means including a bar having a leading face portion, a wear member only on the face portion of each of said bars and having a radial dimension greater than that of the leading face portion of the associated bar, said wear members being removably attached to said bars, said wear members each having a radially inward leading edge and a relieved clearance angle ranging from greater than a angle to substantially a angle with respect to a radius, said clearance angle forming the radially inward trailing edge of each of said wear members to provide a minimum of interference with the path of movement of the particles passing through the mill, said trailing edges lying in planes, the bar associated with each of said wear members being disposed such that no portion thereof extends radially inwardly of a radially adjacent point lying in the associated plane, the innermost edge of each of said wear members having a circumferential dimension of the main body portion of the wear member.

References Cited in the file of this patent UNITED STATES PATENTS 181,924 Ducsh Sept. 5, 1876 250,125 Bennett Nov. 29, 1881 335,827 Mead Feb. 9, 1886 967,042 Ogden et al Aug. 9, 1910 2,016,496 Holbeck Oct. 8, 1935 2,033,757 Crites Mar. 10, 1936 2,155,150 Schacht Apr. 18, 1939 2,623,700 Scherer Dec. 30, 1952 FOREIGN PATENTS 8,066 Great Britain of 1904 322,519 Germany July 1, 1920 372,428 Germany Mar. 27, 1923 379,761 Great Britain Sept. 5, 1932 625,873 Germany Feb. 17, 1936 689,936 Great Britain Apr. 8, 1953 1,056,774 France Oct. 28, 1953