US3829031A - Wear plate - Google Patents

Abstract

A beater mill housing liner formed of a plurality of circumferentially spaced and consecutively arranged wear plate sets cooperating with one another to protect the housing and wear plate sets connecting parts from erosion and to promote the passing of particulate matter into the beater zone.

Description

United States Patent 1191 Kron et a1. Aug. 13, 1974 [54] WEAR PLATE 2,885,156 5 1959 Fitz 241/182 1 1 Heinz Km, Oberhausem Helm-t 3113'??? 271329 11111121213113 :::::::::..?.52 3?8 g Dulsburg-Meiderlch, 3,462,090 8/1969 Landes et a1. 241 /299 0 O ermany 3,659,794 5/1972 Hemesath 241/189 R [73] Assignee: Babcock & Wilcox Limited, London,

England Primary ExaminerGranville Y. Custer, Jr. v Assistant Examiner-Howard N. Goldberg [22] Flled' Sept 1972 Attorney, Agent, or FirmJoseph M. Maguire, Esq.; [21] Appl. No.: 291,472 Robert J. Edwards, Esq.

52 us. c1. 241/182, 241/299 57 ABSTRACT [51] Int. Cl. B02c 17/22 [58 Field of Search; 241/299, 179, 182-183, A beater housmg formed ofaPlurahty of v 241/228 275 189 R cumferlentially spaced and :c} 1nsecut1ve1 ;1 arranged wear p ate sets cooperating wit one anot er to pro- [56] References Cited tect the housing and wear plate sets connecting parts from erosion and to promote the passing of particulate 74 60 i STATES PATENTS matter into the beater zone. 1,1 ,1 /1916 Jensen ..241/183 1,872,036 8/1932 Hardinge .1 241/182 X 2 Claims, 2 Drawing Figures I I3 2o WEAR PLATE BACKGROUND OF THE INVENTION This invention relates to beater mills and is particularly concerned with wear plates used in conjunction with such mills. The prior art is exemplified by German Pat. No. 1,165,975 and Great Britain Pat. No. 688,523.

The former reference shows we'ar plates connected to one another and anchored to the mill housing through a tongue and groove arrangement. The grinding surface of each wear plate is of convex crosssection and is advantageously arranged so that the complement of wear plates forms a grinding surface of alternately spaced crests and troughs which cooperate to redirect the stream of particulate matter to be crushed into the zone of the beater heads. The wear pattern of this arrangement is such that the plates erode out in a concave trough-like shape thus retaining the favorable form of the original arrangement. A disadvantage of this arrangement is the relatively short usage life of the wear plates due to vulnerablity of the plateconnecting tongue and groove arrangement to erosion by the material being crushed in the mill.

The latter reference shows an arrangement wherein wear plates of concave cross-section are interconnected through wedges which are recessed between adjac'ent plates and thereby protected from direct impingement by the stream of particulate matter. A disadvantage of this arrangement is its low milling efficiency since there is no crest and trough pattern to urge the stream of particulate matter back into the crushing zone of the beater mill.

SUMMARY OF THE INVENTION Accordingly, the present invention provides a wear plate arrangement having high milling efficiency coupled with long usage life, and is concerned with the combination of a beater mill and the means for grinding particulate matter flowing therethrough including a housing, a plurality of separate tongue members projecting inwardly from the housing and cooperating with corresponding wear plates to form a circumferential grinding surface facing the crushing devices associated with the beater mill. The wear liner is formed of a plurality of circumferentially spaced and consecutively arranged wear plate sets, each of the sets comprising a first and second element with the first element being disposed upstream particle flow-wise of the second element, each element being of generally arcuate crosssection and having an inner and outer face concentric with the mill housing. The-outer face is contiguous to the housing and includes a grooved portion cooperating with a respective one of the tongue members to detachably connect the element to the housing whereas the inner face is exposed to the flow of particulate matter and forms the grinding surface of the wear liner. Moreover, the inner face of the first element of each set includes a segment formed along a leading portion thereof and curvedly directed toward the mill housing. A wedge of tapered cross-section is recessingly interposed between each of the wear sets and cooperates with adjacent elements to urge the latter in circumferentially opposed directions so as to secure the tongue and groove connection between these elements and the mill housing.

The effectiveness of the present invention can only be achieved through the use of a plurality of consecutively arranged wear plate sets, since the formation of a wear trough on the elements of a given wear plate set is influenced by the next adjacent set located upstream particle flow-wise thereof. Accordingly, the portion of particle stream, flowing along a trajectory tangential to the circular periphery of the beater heads, strikes the second element whereupon it is partially crushed and thereafter tangentially redirected to the crushing zone of the beater heads. Thus, the particle stream is kept from inpinging on the wedge and the thinner portions ofthe first element disposed immediately downstream particle flow-wise of the aforementioned second element; the result being that both the wedge and the tongue and groove connection are protected from the erosive effect of the coarse particulate matter flowing through the beater mill. The direction followed by the particle stream gradually forms a wear trough having a cross-sectional contour which promotes the deflection of impinging particles toward the crushing zone of the beater heads. The trough being formed on each of the elements is along that portion of the surface which is backed by sufficient metal thickness to insure an adequate wear life.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an axial cross-section taken through a beater mill embodying the invention.

FIG. 2 is a detail view of the wear plate arrangement embodying the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2 there is shown a housing 1 defining a chamber 6 of substantially circular crosssection and including a wear liner 15 disposed along the inner periphery of the housing 1 and comprising a plurality of wear plate sets 16, each of the latter being formed of a first element 2 and a second element 3, each element being of generally arcuate cross-section and having an inner face 17 and an outer face 18. The inner face 17 fronts upon the chamber 6 and defines a grinding surfacewhereas the outer surface 18 is contiguous to the inner periphery of the housing 1 and includes a grooved portion 19 cooperating with a tongue member 4 to detachably connect the respective element to the housing 1 as hereinafter described. Each of the tongue members 4 has one end fixedly connected to the inner periphery of housing 1 and projects into chamber 6 along a plane angularly displaced from the radial plane drawn through the tongue member 4 and its point of fixation to the housing 1. The groove portion 19 includes a surface 22 lying in a plane parallel to the projection plane of the tongue member 4 associated therewith. A tapered wedge 5 is recessingly inserted between adjacent wear plate sets 16 and cooperates with the adjacent elements 2 and 3 to urge them in circumferentially opposed directions so as to have the respective groove surfaces 22 bearing hard against the associated tongue member 4 thereby locking the corresponding element onto the housing.

The wear plate sets 16 are arranged in consecutive fashion with the element 2 in each set being located upstream particle flow-wise of the element 3 of the same set. The direction of flow of coarse particulate matter to be crushed is shown by a directional arrow 8; this also being the direction of rotation of the beater heads (not shown) and which follow the circular path defined by the dotted line 7. Each of the elements 2 is formed with the leading portion of its inner surface 17 curvedly sloped in the direction of housing 1 with the remainder of the inner surface being of arcuate cross-section. The element 3 has its entire inner surface 17 formed of an arcuate cross-section and its trailing end face 14 projecting inwardly past the wedge 5, the latter being recessed between wear plate sets such that its inner face lies along a plane which is intermediate that of the inner and outer faces 17 and 18, respectively, of the element 3.

During operation of the beater mill, each wear plate set 16 influences the next adjacent wear plate set located downstream particle flow-wise thereof as shown by the sets further identified as A and B on the drawing. A portion of the stream of particles passing through the beater mill strikes the inner face 17 of the element 3, as indicated by a directional arrow 9, and is thereafter deflected in the direction of the beater circle 7 thereby avoiding striking the wedge 5. All of the particles which strike the element 2 of wear set B, as indicated by a directional arrow 11, gradually form a wear trough 12 which in turn promotes the redirection of these particles into the beater circle 7, as indicated by a directional arrow 13.

A series of test incorporating the present invention indicates that the usage life of a set of wear plates has been considerably extended and the utilization of wear material has likewise been improved by approximately percent.

What is claimed is;

l. The combination of a beater mill and means for grinding particulate matter flowing therethrough including a housing formed with arcuate wall portions, each of the wall portions having an inner periphery lined with circumferentially spaced wear plate sets, each of the sets comprising a first and second plate, said first plate being spatially disposed upstream particle flow-wise of the second plate, said first and second plates having convex base and concave wear surfaces, said surfaces being concentric with the wall portions, the first plate including a convex wear surface formed upstream particle flow-wise of the concave surface and being merged therewith, and wherein opposed end faces of adjoining wear plate sets converge toward one another in the direction of the wall means, means for securing the wear plates to said wall means including at least one groove formed in the base of each plate, tongue means anchored to said inner periphery and projecting therefrom to engage said groove, and a tapered wedge recessingly interposed between said end faces and urging the corresponding plates in circumferentially opposed direction thereby locking the respective tongue means and grooves.

2. The combination according to claim 1 wherein opposed end faces of said first and second plates extend parallel to one another and normal to said inner periphery.

v UNITED STATES CERTIFICATE OF CORRECTION Patent No. 3,829,031 Dated October 7, 97

Inventor(s) Heinz Kron andv Helmut Grommes It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column L, line 17, substitute --portions-- I for the first named "means"; line 18, substitute I n "portions" for "means"; line 2 L, "direction should.

' read; --directi0ns--.

Signed and sealed this 10th day of December 1974.

(SEAL) Attest McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents FORM PC3-1050 (10-69) v USCOMM DC eovbpu I w 0.5. GOVERNMENT manna omc: l9 o-uc-azu.

Claims (2)

1. The combination of a beater mill and means for grinding particulate matter flowing therethrough including a housing formed with arcuate wall portions, each of the wall portions having an inner periphery lined with circumferentially spaced wear plate sets, each of the sets comprising a first and second plate, said first plate being spatially disposed upstream particle flow-wise of the second plate, said first and second plates having convex base and concave wear surfaces, said surfaces being concentric with the wall portions, the first plate including a convex wear surface formed upstream particle flowwise of the concave surface and being merged therewith, and wherein opposed end faces of adjoining wear plate sets converge toward one another in the direction of the wall means, means for securing the wear plates to said wall means including at least one groove formed in the base of each plate, tongue means anchored to said inner periphery and projecting therefrom to engage said groove, and a tapered wedge recessingly interposed between said end faces and urging the corresponding plates in circumferentially opposed direction thereby locking the respective tongue means and grooves.

2. The combination according to claim 1 wherein opposed end faces of said first and second plates extend parallel to one another and normal to said inner periphery.

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