The practical draughtsman's book of industrial design and machinist's and engineer's companion : forming a complete course of mechanical, engineering and architectural drawing . the stones run empty, no contactcan take place, therefore there is no firing, nor does a variation inthe feed or speed cause any difference in the relative position ofthe stones, on account of the firm and steady revolution on thecurved pivots. Tho antifrictional qualities of these pivots arepretty well elucidated by the fact of the very minute consumptionof oil upon them. The Ring Millstone, invented byMr. Mullin of G
The practical draughtsman's book of industrial design and machinist's and engineer's companion : forming a complete course of mechanical, engineering and architectural drawing . the stones run empty, no contactcan take place, therefore there is no firing, nor does a variation inthe feed or speed cause any difference in the relative position ofthe stones, on account of the firm and steady revolution on thecurved pivots. Tho antifrictional qualities of these pivots arepretty well elucidated by the fact of the very minute consumptionof oil upon them. The Ring Millstone, invented byMr. Mullin of Gilford, Ireland, is pro-posed as the means of securing fourspecial advantages—economy in ma-nufacture, simplicity and effective ven-tilation, increased production of meal,and a saving of labour in repairs. is a vertical section of the stone, andfig. 5 is a corresponding plan. The eye, a, is made excessively large inproportion to the stones diameter, ex-ceeding, indeed, half the latter dimen-sion. This increased area admits a greater volume of air than is usual, and this air, coming in contactwith the more rapidly revolving portion of the stone, is passed Fig. 166 THE PRACTICAL DRAUGHTSMANS between the working surfaces by the action of the centrifugalforce. Besides, the increased circumferential length of the eyeadmits of the formation of three or four times the ordinary numberof leading furrows, for the distribution of the air over the grindingsurfaces, and thus more grain is ground, without any risk of over-heating by friction. Finally, by getting rid of the great area ofsuperabundant stone at the centre, the operation of dressing is ob-viously simplified very considerably. Mr. Barnett of Hull has ingeniously enough contrived a per-meable millstone, capable of dressing a great portion of the flourduring the actual grinding process. Fig. 6 is a sketch of thisstone. As soon as the grinding has commenced, the fine flourwhich is liberated passes over a set of radial wi
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Keywords: ., bookcentury1800, booksubjectarchitecturaldrawing, booksubjectmec
