. The practical draughtsman's book of industrial design, and machinist's and engineer's drawing companion: forming a complete course of mechanical, engineering, and architectural drawing . e two feed-pipes passvertically through a pair of holes made directly through theupper stone, and set diametrically, one on each side the eye ofthe stone. An annular portion of the under surface of this stone,extending far enough to reach the feed apertures opening throughit, is bevilled slightly upwards from the outer side of these holestowards the eye, so as to leave a narrow space between the twostones at
. The practical draughtsman's book of industrial design, and machinist's and engineer's drawing companion: forming a complete course of mechanical, engineering, and architectural drawing . e two feed-pipes passvertically through a pair of holes made directly through theupper stone, and set diametrically, one on each side the eye ofthe stone. An annular portion of the under surface of this stone,extending far enough to reach the feed apertures opening throughit, is bevilled slightly upwards from the outer side of these holestowards the eye, so as to leave a narrow space between the twostones at this part, for the free entry of the grain and air, andprecluding the chance of the commencement of the grindingaction, before the air has fully reached the acting surfaces. Theeye of the upper fixed stone, between the two feed-pipes, iscovered over with a metal disc, G, passed over the feed-spindle,and capable of adjustment at any required height above the eye BOOK OP INDUSTRIAL DESIGN. 167 as a valve. The grinding surface of the lower running stone, H,is perfectly flat throughout, and its eye at the grinding level iscovered over by a metal plate, F, with a central aperture round. the feed-spindle, G, for the passage through of a portion of theair. In this way, part of the air may be discharged at the eye ofthe upper stone, and part down through the eye of the runnerbeneath, whilst the main body of the air goes along with thegrain, and is discharged with the grained material at the peripheryof the stones. By this contrivance, the entire surface of bothstones is kept encircled by a constantly changing air-bath orcurrent, for the air, escaping at the eye of the upper stone, isdirected by the valve disc over its entire surface, whilst that fromthe bottom of the lower eye passes over the whole bottom surfaceof the runner, between it and the bottom base plate, I. This hasa ventilating effect; for on the upper edge of the iron casing, j,which surrounds the lower running stone, and
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Keywords: ., bookcentury1800, booksubjectdecorativearts, booksubjectdrawing
