US3003708A

US3003708A - Impact crusher

Info

Publication number: US3003708A
Application number: US22609A
Authority: US
Inventors: Joseph W Leonard
Original assignee: United States Steel Corp
Current assignee: United States Steel Corp
Priority date: 1960-04-15
Filing date: 1960-04-15
Publication date: 1961-10-10
Anticipated expiration: 1978-10-10

Description

Oct. 10, 1961 J. w. LEONARD 3,003,708

IMPACT CRUSHER Filed April 15, 1960 INVENTOR J OSEPH m LfO/VARD B! Aria/nay United States Patent Jersey Filed Apr. 15, 1960, Ser. No. 22,609 4 Claims. (Cl. 241-81) This invention relates to an improved impact-type crusher.

Although my invention is not limited to use with any specific material, it is particularly applicable to coal. Previous crushers with which I am familiar effectively reduce the size of coal particles, but have a disadvantage that they produce too many fines. A large proportion of fines is objectionable in crushed coal used for certain purposes, such as the manufacture of metallurgical coke or for sinter fuel. For example, a strong coke can be manufactured from coal crushed to minus 8-mesh, but the minus IOO-mesh fines tend to leave the coke oven with the gas. If a large proportion of such fines are present, they tend to lower the bulk density of the coke and the yield, besides creating a problem in cleaning the gas. Nevertheless it is apparent my invention can be used with other materials where similar problems arise.

An object of my invention is to provide an improved impact-type crusher which elfectively reduces the size of particles without producing any substantial quantity of fines.

A further object is to provide an improved impact-type crusher in which impact loads are obtained by throwing the particles at velocities varying with the initial particle size, that is, in which smaller particles have lower velocities to diminish the tendency to break them into fines.

A more specific object is to provide an improved impact-type crusher which includes a tapered rotor for throwing particles against impact plates at velocities varying with the initial particle size, thereby diminishing the tendency to pulverize small particles to even finer sizes.

In accomplishing these and other objects of the invention, I have provided improved details of structure, a preferred form of which is shown in the accompanying drawing, in which:

FIGURE 1 is a side elevational view, with parts broken away, of a crusher constructed in accordance with my invention along with a suitable feeding device; and

FIGURE 2 is an end elevational view, with parts broken away, of the crusher alone.

As shown in the drawing, my crusher comprises a housing 10, a rotor 12 and a plurality of impact plates 13 within said housing, and feed and

discharge hoppers

14 and 15 at the top and bottom of the housing. The rotor is fixed to a horizontal shaft 16 which is journaled in bearings 17 at opposite ends of the housing. The shaft and rotor are driven in a clockwise direction, as viewed in FIGURE 2, by any suitable means not shown. The rotor is conical, tapering from left to right as viewed in FIGURE 1. The tapered face of the rotor carries a plurality of throwing arms 18 preferably spaced 90 apart. Each impact plate 13 is individually suspended from the top wall of the housing on respective pairs of eyebolts 19 and 20, whereby its position with respect to rotor 12 can be adjusted. The impact plates are crescent-shaped and they extend opposite the rotor approximately from the one oclock position to the four oclock position. The impact plates preferably have scalloped inner faces directed toward the rotor. The feed hopper 14 is located over the rotor axis and it contains a series of transverse vertical partitions 21, which divide it into individual compartments 22 corresponding with the impact plates 13.

3,003,708 Patented Oct. 10, 1961 A feeding device 23 is situated above the feed hopper 14. The feeding device can be of any suitable construction for dividing the-feed into a plurality of size fractions corresponding with the number of compartments 22 and impact plates 13. The feeding device illustrated includes a hopper 24 in which a plurality of vibrating screens 25 are mounted. The screens have openings of diminishing size from the uppermost downwardly. A conveyor 26 or the like introduces material to the uppermost screen. Individual chutes 27 carry the material retained on each screen 25 and on the bottom of hopper 24 to the respective compartments 22 of the feed hopper I4.

In operation, I introduce minus 3-inch material, such as coal, to the feeding device 23, which separates the material into size fractions corresponding in number to the compartments 22. The coarsest size fraction feeds to the compartment at the left, while fractions of successively diminishing particle size feed to other compartments in order. Rotor 12 turns at about 300 to 600 rpm. The linear velocity of the throwing arms 18 is of course greatest at the left end of the rotor and progressively diminishes toward the right end. Coarser size fractions feed to portions of the rotor where the linear velocity is greater, and size fractions of diminishing particle size feed where the linear velocity diminishes. Thus the throwing arms 18 throw particles against the impact plates 13 at velocities which vary with the initial particle size. Coarser particles have greater velocity, and thus receive greater impact loads when they strike the plates 13. Smaller particles have less velocity and receive smaller impact loads, whereby there is less tendency to pulverize them even finer.

From the foregoing description it is seen that my invention affords a simple and effective crusher for reducing the size of particles, such as coal, without producing excessive fines. Since the impact load on particles varies directly with their weight and with the square of their velocity, the impact load applied to smaller particles is greatly diminished over that applied to larger particles.

While I have shown and described only a single embodiment of my invention, it is apparent that modifications may arise. Therefore, I do not wish to be limited to the disclosure set forth but only by the scope of the appended claims.

I claim:

1. A crusher comprising a housing, a rotor journaled in said housing, at least one impact plate mounted in said housing opposite said rotor, throwing arms mounted on said rotor to travel at varying linear velocities along their length on rotation of the rotor, and means for feeding to said rotor material separated into size fractions with coarser particles in the material going to the portions of the arms which travel at greater linear velocities, said arms being adapted to throw particles against said plate at velocities which vary with the initial particle size.

2. A crusher comprising a housing, a tapered rotor journaled in said housing, at least one impact plate mounted in said housing opposite said rotor, throwing arms fixed to the tapered face of said rotor to travel at varying linear velocities along their length on rotation of the rotor, and a feed hopper at the top of said housing for feeding to said rotor material separated into size fractions with coarser particles in the material going to portions of the rotor of greater diameter where the arms travel at greater linear velocities, said arms being adapted to throw particles against said plate at velocities which vary with the initial particle size.

3. A crusher comprising a housing, a tapered rotor journaled in said housing, a plurality of impacted plates within said housing suspended from the top thereof opposite said rotor for individual adjustment, a plurality of circumferentially spaced throwing arms fixed to the tapered face of said rotor to travel at varying linear velocities along their lengthen rotation of the rotor, and a feed hopper at the top of said housing for feeding to saidrotor material separated into size fractions with coarser particles in the material going to portions of the rotor of greater diameter where the arms travel at greater linear velocities, said arms being adapted to throw particles against said plates at velocities which vary with the initial particle size. 7

4. A crusher comprising a housing,ya tapered rotor journaled in said housing, a plurality of impact plates within said housing, individually adjustable means suspending said plates from the top of said housing, said plates being located opposite said rotor and extending approximately from the one oclock position to the four oclock position with respect thereto, a plurality of circumferentially spaced throwing arms fixed to the tapered face of said rotor to travel at varying linear velocities along their length on rotation of the rotor, a feed hopper at the top of said housing for feeding material to said rotor, and transverse partitions in said hopper dividing the hopper into compartments corresponding with said plates, said compartments being adapted to receive different size fractions of the material and to direct coarser particles to the portions of the rotor of greater diameter where the arms travel at greater linear velocities, said arms being adapted to throw particles against said plates at velocities which vary with the initial particle size.

References Cited in the tile of this patent UNITED STATES PATENTS 2,032,827 Andrews Mar. 3; 1936 2,110,851 Symons Mar. 8, 1938 2,362,351 Bur-meister Nov. 7, 1944 2,468,321 Bland Apr. 26, 1949