OCR Text |
Show SYSTEMATIC PREPARATION OF MINERALIZED ORES BY DRY CRfSHISG AXD COXCEXTRA-TIO COXCEXTRA-TIO V. IV. -Ul":LUNG ROLIjt-. The device popularly known as the Cornih crukiii!; rolls has never been surpassed ia the ib'Iowin essential features: compactness, simplicity of construction, durability of the tised parts, facility of repair of the parts ,-ub-ject to wear, economy oi' work per ton. and the low ratio of lir.-t cost rated by the ton of capacity. When fiiat introduced, intro-duced, the fincle stamp head, or rude combination; of scw-ral heads in battery bat-tery form, were the only com pel inc de. vices for ctushine; tliee Wug iuUT-mittent iuUT-mittent in exeuuLion, s-iciueJ to oiler but a feeble opposition to a preference for continuous action of rapidly revolving revolv-ing surface-", so arm aged as to impince upon the feed unintcnipiedly. But in practice the stamp-mili proved the possession pos-session of one feature tuleiently impor- tant to give that mode of cruohinp superiority su-periority over the roils, viz: the automatic auto-matic or natural adjust tuent of the wearing parts, so that production continued con-tinued the same in rpir.lity and nuantity from lirit to last, untii the war-ted parts had to be replaced. The stamps were, thcrelbre, successfully improved and brought to a hi eh state ni' efficiency, whilst the Cornish rolls have remained almost as ihpy were ori;inally constructed. construc-ted. The former have been pressed into almost universal mtvk-c and frequently fre-quently compelled to do a duly fur Vjhieh they are nut adapted. a::d oftentimes often-times whoIljMneonsisU'iit with the purposes pur-poses to which the crushed material was subsequently de.-tiut'd, whilst the latter has been mdilL rcntly as.-icneu (o special work, as if there w,is a radical defect, irremediat, aij, ilierel'jre, destructive de-structive to all the oilier features, which, had they not be n ihu-; impaired, nuuiu IhlR-gaLMI LU lliL V"l Iil.-ll TOlIS a precedence over every other d vice for crushing ores rcquiriitcr a -vc'iM tuutiip-ulation tuutiip-ulation for metalluraieal pnrpo es. The positive clement-, oi' Mipi-riority possessed by the (Jorni.-h rolls, have hitherto been f-tranccy undervalued until recently, when Mr, Krem undertook under-took to complete a systematic preparation prepara-tion of ores which should cmbraco the best devices, each especially adaj)ted to the particular duly devolved upon it, and all adapted to work in a combination, combi-nation, comprehending every feature essential to unvarying results in quality and certainty in quantity, at a minimum mini-mum of cost in plant, as well a a miu-iruum miu-iruum of cost in production. The stamp-mill was not suited for litis combination. com-bination. Two objections, both insurmountable, insur-mountable, prevent its adaptation, viz: excessive cost in dry work and excessive ex-cessive product of line stull', unsuited to the work of concentration, whereas ihe rolls produced only dry work, and that cheaply, while making also a minimum min-imum percentage of line stuff. Ilad the defect, already referred to, been irretnedial, such a system ruiht have been impracticable. A study of the rolls proved that all attempts heretofore hereto-fore made to overcome the difficulty were neither in tho right direction nor sufficiently complete to reach the end desired. Briefly described, this difficulty diffi-culty resided first, in the speedy wear of tho impinging surfaces of the rolls, productive of uneven work, increasing in quantity as the wear went on. Secondly, Sec-ondly, in employing a material for the face of the roils subject to great inequality in-equality of wear, and when worn into ridges incapable of readjustment. Gearing had been adopted for meeting tho wear of crni surfaces, which wholly failed to meet the wants when tho wear was uneven forming many cavities, grooves and ridges on the surfuco of the rolls. Chilled faces had been employed to lessen this wear, but with d iTere&t success, suc-cess, inasmuch as tho chilling was superficial su-perficial and subject to great inequality in hardness. For the same purpose Franklinite iron wis substituted with greater advantage, but still unsatisfactory. unsatisfac-tory. In neither ease could there be provided any means of lining up the worn surface on account of the hardness hard-ness of the material. Wrought iron wna substituted with greater advantage advan-tage in regard to evenness of wear, but involving too frequent changes of new for old. During this while little or no improvement was sucgeoUd in the detail of construction. Rigidity had to be compensated for by the adoption of levers, springs, weight and rubber, originating auoiher defect while overcoming over-coming an existing evil. No means were taken to prevent waste of oil, reduce re-duce attendance, supply Iced regularly, in line, to produce a machine which embodied these essential rrquisites : 1st. Positive adjustability to the wear, thcrelbre continuous equality in results. 2d. Rigidity in centers oi' revolution revolu-tion with a means of positive safely in cases of accidental emergencies, therefore there-fore non-liability to a separation of the impinging surfaces when not required. re-quired. 3d. Regularity in feed, thereby preserving pre-serving evenness of comminution and lessening the return of insufficiently crushed matter. 1th. Provision for saving oil waste, thereby preserving the machine from tilth as well as a needless expense. 5th. Facility for replacement of parts worn to the minimum of waste, thereby saving time, labor and cost of repairs. i th. Combining strenzth of parts with the minimum of weight, thereby lessening the first cost and the cost of transportation, while giving to the machine ma-chine a compactness and a finish which, in connection with the other improvements mentioned, must entitle it to be considered first-class m every essential feature. The methods by which thce improvements im-provements have been reached arc the followinc: (n). The suh-titution of steel dics, rines or faces for the wearing surfaces, sufficiently hard to resist exces.-ivi wear, yet soft enough to allow re-adjustment by being trued up, in place, by means provided for that purpose. Both chilled and Frankimite iron are condemned for the reasons named, and steel sub-tituted for wrought iron, be-caue be-caue of its liner texture, greater rc d--tcoce, eventicss of wear and the existence ex-istence of present facilities procuring steel fur this purpo-e at no excessive' advance in ol. The linal wane of steel when worn is red tic. d to a minimum mini-mum quantity. J inch in d-'pth on the ' circumference of the roil, and this in ; a condition to brins almost the fir--l cost of the raw materia!. I (-'. The rultituiinn of "breaking cups" to rep. ace cumbrous levers, irregularly irre-gularly acting springs and rubber eaf-ety eaf-ety devices. T.ic.-e etips are so p;aced that any aecidtntai ob--iruclion between the imjTicgirg turlac-a cm be paed through at tue expen.-e of the cups, easily duplicated, wh:.st the rigt iity ol the center? ut revolution is main-laincl main-laincl d'lrtsg tho rc,-'j.ir opratin of the lunch ;ne. The provMlnc a re j-ilar fei-dinc device to prevent ov'M-rrovs.iir..-. he tec a sepajiUvn of the imr.iCkiDt surfaces, thereby allowing uncnished ore to pas-5 unnecessarily, iccuring loss in time and power in re-working what should have been finished on its first passage. (i). Providing oil cups for feeding the oi!, and "oil drips" for securing the overplus, thereby preventing a useless waste, while protecting the parts exposed ex-posed from the accumulation of a deposit de-posit of matter objectionable in many respects. r). Providing a new method of securing se-curing thejliscs or rings of steel which, while affording positive security against misplacement, allows of easy adjustment in putting on new or in taking off worn-out rings. I (. j. Remodelling the heavy parts of the machine, providing rigid steel journa!s instead of flexible " wrought iron, doing away with many cumbrous contrivances and inconvenient devices which have heretofore escaped the notice of mechanics engaged in following follow-ing the beaten tracks when producing thia machine. The crushing rolls, as now furnished by Mr. Krom, are manufactured with the utmost care, every part made to a standard gauge in order that any portion por-tion can be duplicated and interchanged. inter-changed. The general result is a machine combining the requisites first mentioned as distinctively belonging to the Cornish crushing rolls, but he realization of which has been hitherto so inadequately obtained. As now placed before the mining public, they possess compactness, simplicity of con-strueiion, con-strueiion, durability of the fixed parts, facility of repair of parts subject to wear, economy of work per ton, and a low ratio of first cost rated by the ton of capacity. G. V. Baker. |