US2974889A - Relief inserts for metallic lining - Google Patents

Description

March 14, 1961 w, ANDERSON ETAL 2,974,889

RELIEF INSERTS FOR METALLIC LINING Filed May 7, 1959 7 I ,(Z t A 25 Ii 23 "I 22 29 30 L 3 i ll gm Fiji IN V EN TORS EA YM 0ND A/VDAPSON & CLARE/v66 KA M200 BY 1 i W/ fizz/$0,, A21 MM A TTOE/VEVS United States Patent RELIEF INSERTS FOR METALLIC LINING Raymond W. Anderson and Clarence F. Kamrud, Babbitt, Minn., assignors to Reserve Mining Company, Silver Bay, Minn., a corporation of Minnesota Filed May 7, 1959, Ser. No. 811,716

Claims. (Cl. 241-295) The invention relates to an improvement in mechanical crushing devices, and particularly to a novel and improved lining means disposed between a crusher element and its support. The invention will be described in one useful adaptation comprising an ore crusher utilized in the breaking to a predetermined size of hard rock fragments, for example fragments of the low grade iron ore known as taconite.

Present day methods of producing commercially useful quantities of iron from taconite ore sources call for what is known in the art as beneficiation of the minerun ore. One successful process of beneficiation of said ore comprises generally the initial steps of coarse and fine crushing, whereby the ore, as removed from the mine is broken up into successively smaller particles or lumps; secondly, concentration, wherein the ferrous material from said ore is comminuted and separated from the gangue material or tailings; and thirdly, pelletizing, wherein the concentrated ferrous material may be combined with binder and coating materials such as bentonite and pulverized coal and then formed into pellets in a manner known in the art.

The crushers which normally perform the coarse and fine crushing of the mine-run ore are preferably controlled so that a predetermined size of particle or lump is obtained. In one specific operation to be hereinafter referred to as an exemplification of the use of the invention, a coarse crusher is controlled to deliver particles or lumps having at least one dimension less than seven inches, and one type of subsequent fine crusher is normally controlled to deliver particles or lumps having at least one dimension of less than four inches. The particle sizes as above referred to may be changed if desired in order to facilitate the crushing process in particular circumstances, and also if it is determined that other suitable sizes are more readily adaptable to the remaining process steps in the beneficiation of said ore material.

One type of coarse crusher which may perform this operation is known as a gyratory crusher and comprises generally a stationary shell of substantial cylindrical configuration having a plurality of plates or concaves, as referred to in the art, rigidly fastened to and lining the interior wall thereof to define a fixed substantially annular crushing surface having a reduced waist portion.

A mantle generally conically shaped in external configuration, is mounted on a shaft, the latter being disposed vertically and supported on its lower end such that the mantle extends upwardly within the shell. The mantle is spaced radially inwardly of the concaves to provide a downwardly converging annular space therebetween defining an ore crushing zone. The mantlecarrying shaft is normally gyratably driven from its lower end such that the mantle alternately approaches and recedes from the concaves to a limited extent at any point, except at the center of gyration, and hence, as the particles of ore material fall into the crushing zone, the same are nipped or crushed. The mantle is usually formed of a wear resistant material such as manganese ice steel of a predetermined thickness, as are the concaves, so that the crusher may be operative over prolonged periods of time before excessive wear requires replacement of said crushing members, The shaft is usually constructed and attached to its drive in a manner permitting limited endwise movement and it may be raised and/ or lowered to any desired position within the shell by any suitable means so as to provide a predetermined spacing between the crushing members and hence to regulate the clearance aperture of the annular throat for the crusher. This throat is defined as the annular opening between the adjacent lower ends of the mantle and concaves and this opening determines the ultimate size of particle or lump output from the crusher.

Since the greatest mantle wear is encountered in the region of the throat it is considered economically desirable to cast the mantle in two sections, of which a lower section takes the heaviest working impacts and a higher section sustains the abrasive action of the descending rock fragments. In one preferred embodiment the upper mantle section covers the upper third of the mantle support (sometimes termed a head center) and can be used at least several times with replacement lower portions.

The mantle sections are cast from manganese steel. As the lower section is subjected to continuous grinding it grows, just as a. metal ring increases in diameter if it is placed around an anvil nose and hammered. In current practice a lining of zinc or other lower melting point metal is interposed between the mantle sections and the head center to fill in depressions or compensate for nonmatching irregularities in the adjacent surfaces of the head center and the mantle, As the lower mantle section grows it slides downwardly on the zinc liner. The upper mantle section, receiving the pounding and wear to a lesser extent, grows more slowly than the lower section and consequently does not keep pace with the lower section. As a result there develops an interstitial space between the upper face of the lower mantle section and the lower face of the upper section. Rock dust and fragments, which are abrasive in character, work into this space and enlarge it unevenly. This also tends to permit loosening of the upper section and head-clamping nut.

An object of the present invention is to provide novel and improved means which permits the upper mantle section to maintain contact with the lower mantle section as they mutually wear, though the upper section is subjected to a lesser degree of pounding and wear.

A further object of the invention is to provide yieldably collapsible insert means in the lining of the upper mantle section which facilitates a predetermined amount of shrinkage in lining volume, and thereby permits the upper mantle section to more readily follow and maintain contact with the lower mantle section.

Other objects and advantages will be apparent from a study of the following description of one embodiment of the invention, in conjunction with the accompanying drawings, in which- Fig. 1 is a view, partially in side elevation, with parts roken away to show internal structure, and other parts in vertical section, showing a rock crusher with a mantle arrangement in accordance with the present invention.

Fig. 2 is a horizontal sectional View taken on the line 2-2 of Fig. 1.

Referring now to the drawings, the novel and improved features of the present invention are herein illustrated by way of example, and not as indicative of its scope of utility, for use with a gyratory vertical type ore crusher which is used to perform a coarse crushing operation. The disclosed form of crusher, as viewed in Fig. 1 includes an elongated vertically upstanding barrel or shell 3 comprising a lower part 4 and an upper part 5. The lower end of said latter part is mounted and securely fastened to the upper end of said lower part 4 in substantial axial prolongation such as to provide such shell with a continuous interior cavity 7. A plurality of ring shaped concaves 9 are constructed of a; suitable hard metallic material, each concave having abacking or support member (not shown) usually formed of a concrete base material and shaped to conform to the interior configuration of each of said concaves. Said concaves are rigidly fastened to the interior wall of the upper part of the shell 3 in such manner as to provide a substantially continuous annular crushing surface 12.

The present embodiment of crusher also includes a movable crusher head 14 carrying mantle portions 15a and 15b of frusto conical contour and rigidly mounted over a similarly shaped base 16. The crushing head 14 is firmly fixed upon a drive shaft 17, the latter having a medial tapered portion 13 extending centrally through the base 16 and engaging the latter in a press fit relation. The mantle portions 15a and 15b are also constructed of a suitable hard metallic material.

The crusher shell 3 is normally mounted on a base such as indicated at 21 in Fig. l and rigidly secured thereto by any suitable fastening means such as bolts 22 and nuts 23 in threaded engagement with the latter such that the lower part 4 and upper part 5 of said shell extend substantially vertically upwardly. The crushing head 14 is disposed centrally within the shell, the conical shaped mantle being spaced inwardly of the concaves so as to form therebetween a downwardly converging annular crushing zone, as is indicated by the reference character A.

The shaft 17 extends downwardly below the bottom of the shell 3and at its lower end is adapted to be eccentrically driven by means now to be described.

An elongated sleeve 25 is placed over the lower end of the shaft 17, in such manner as to permit the latter to be freely rotatable and also to allow said shaft to be adjustably moved in a longitudinal direction by means to be presently described. An elongated eccentric bushing 26' embraces the outer surface of the sleeve 25, being securely fastened thereto by suitable means such as dowel pins 27. A bevel gear 28 is firmly attached to the lower end of the eccentric bushing 26, and is rotatably driven by means such as pinion gear 29. As shown in Fig. 1, the pinion gear 29 is mounted on the inner end of drive shaft 30, the latter being rotatably supported adjacent its ends by bearing supports 30a mounted in the lower part of the shell 3. Any suitable drive means such as an electric motor '(not shown) may be adapted to rotatably drive the pinion shaft 30 and thereby rotatably actuate the bevel gear 28 and connected eccentric 26.

Iln this manner the shaft 17 and attached mantle 14 are gyratably driven such that the mantle is alternately carried toward and away from successive peripheral points or areas on the crushing surfaces 1 2 formed by the concaves 9 thereby orbitally varying the crushing zone so that as the ore material moves downwardly into and through said zone it is successively crushed to smaller sizes and finally is discharged from the crushing zone through the crusher throat 31, namely the annular opening between the adjacent lower ends of the stationary crushing surface 12 and the lower mantle portion 15b. The crushed particles fall into the lower part 4 of the shell 3 wherein they are picked up and transported by suitable means such as an endless conveyor (not shown) and deposited into storage bins or the like in readiness for further steps in the beneficiation process.

In assembling the mantle portions on their associated supporting elements, including shaft 17 and crusher head 16, the head is given a press fit on the shaft. The shaft is then disposed in an upright position, supported from its bottom end, and the mantle parts 15a and 151: are lowered around head 16, the mantle being supported from underneath on a peripheral series of adjustable supporting bolts 34. There is an annular clearance space between the mantle and head 16, and, in the described embodiment, molten zinc is poured into the annular space.

The practice so far described represents the prior art arrangement. In our own procedure, however, we supply a plurality of yieldable members in the annular space between the upper mantle part and the crusher head. These are inserted in circumferentially spaced relationship before pouring the zinc, and the zinc is then poured so as to trap the yieldable members when the zinc solidifies. In the present instance we insert four lengths of thin-walled tubing 35, each length beingbent over at its top end 35a so as to hang from the top end of mantle portion 15a. The tubing hangs downwardly two-thirds of the length of mantle part 15a and is sealed or closed at the bottom to prevent the molten zinc from flowing into the tubes. We therefore have relief ports in the zinc lining 36 which collapse rather readily if the lining 36 tends to deformor expand.

As a result, although the upper mantle part 15a and its underlying zinc layer are not subject to such severe working stresses as are the lower mantle part 15b and its respective zinc underlay, the upper zinc lining exerts axial pressure on the yieldable inserts 35 which collapse, and give the upper zinc lining more elbow room so to speak, so that the upper mantle part is permitted by gravity to slip downwardly sufiiciently to maintain contact with the upper edge of lower mantle part 15b. As a consequence no space develops between the two mantle parts. It is of interest to note that if the upper mantle section, when equipped with relief zones as hereinabove described, is removed by melting out the intermediate zinc layer, and later again assembled and used for a second time the number of tubing sections may be reduced, for example to three instead of the four shown in Fig. 2, because the used mantle section has been worn thinner and grows faster, and consequently does not require so many relief zonesp What is claimed is:

1. In a gyratory crusher, a crushing cone, a central member on which said cone is supported, and a metallic low-melting-point liner between said cone and said central member, said liner having integrally cast therein a pluralityof relief members ada ted to yield under external pressure and permit axial displacement of said cone.

2. Ina crusher, a central gyratory shaft, a conical mantlecarried by said shaft, and 'a metallic low-meltingpoint liner between said shaftand said mantle, said liner having integrally cast therein a plurality of elongated, hollow, thin walled relief members adapted to collapsibly yield under pressure whereby to permit limited axial slip of said mantle.

3. A crusher of the type defined in claim 2 wherein said relief members are relatively evenly spaced circumferentially around and within said liner.

4. A crusher of the type defined in claim 2 wherein said relief members consist of lengths of relatively thinwalled tubing extending longitudinally within said liner.

5. In a crusher of the type having a central supporting means and an oversize hollow, conical mantle carried on said central supporting means, said mantle being formed from a metal adapted to increase in diametrical extent under impacts sustained during crushing, a liner filling the space between said mantle and said supporting means, said liner having integrally cast therein a plurality of circumferentially spaced, hollow, thin, walled relief members adapted to yield under pressure whereby to permit axial displacement of the mantle.

6. A crusher liner of the type defined in claim 5 wherein said relief members consist of lengths of relatively thin-walled tubing extending longitudinally within said liner.

7. In a gyratory crusher a central shaft constituting a mantle support, a hollow mantle carried on said support and split transversely to the shaft axis to provide an upper mantle portion and a lower mantle portion, said mantle being oversize with respect to its support to provide a space therebetween, a low-melting-point metal cast in place in said space, the liner part inwardly between said upper mantle portion and its support having therein a plurality of relief members adapted to yield under external pressure and permit axial displacement of said upper mantle portion.

8. A crusher of the type defined in claim 7 wherein said relief members consist of lengths of relatively thinwalled tubing extending longitudinally within said liner.

9. In a gyratory crusher a central shaft having a conically tapered mantle support therein, a hollow mantle carried on the outer tapered surface of said support, said mantle being transversely split on a plane normal to the shaft axis to provide an upper mantle portion and a lower mantle portion in adjacent end contact, said mantle being oversized with respect to said support to pro- 20 1,459,305

vide a space therebetween for the reception of a cast in-place liner of a relatively low melting point metal, a plurality of circumferentiall' -spaced thin-walled hollow relief members imbedded in said liner within said upper mantle portion, said relief members being adapted to be collapsible under externally applied pressure whereby to permit downwardly following movement of said upper mantle portion under severe crushing impacts whenever said lower mantle portion moves downwardly under more severe crushing impacts.

10. A crusher of the type defined in claim 9 wherein said relief members consist of downwardly extending lengths of thin-walled tubing spaced substantially evenly around the liner circumference.

References Cited in the file of this patent UNITED STATES PATENTS Hunter July 1, 1913 Kennedy June 19, 1923

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