BOLTING MACHINE. A part of the machinery of a flour mill, by which the flour is separated from the meal, which operation is termed dressing the flour. It usually consists of an hexagonal reel, over which is drawn a sack, called the bolting cloth, of considerably larger diameter than the reel, and composed of a peculiar species of duck made for the purpose. The reel is placcd in an inclined position, and made to revolve rapidly within six bars of wood, called beaters, fixed to a case or box, within which the reel revolves. The reel being turned with great velocity, the centrifugal force would throw out the bolting cloth to its utmost extent were it not intercepted by the beaters; the repeated blows from these first force the flour through the interstices of the cloth, and subsequently, at the tail end of the reel, the offal consisting of bran, pollard, and sharps. The above engraving represents Ayton's improved Flour Bolting Mills, constructed upon the principle just described, but provided with the means of more easily and effectually regulating the tension and elas ticity of the bolting cloth, so as to produce in it a uniform and powerfid tion, which is effected by secured loops at one end of the cloth to six elastic steel arms or springs, instead of the stiff arms of the common construction.
Fig. 1 is a plan or front view of the steel arms a a, and Fig. 2 a side view of the same in section. These arms are rivetted to a ring of metal c, and at their outer extremities are formed into broad flat hooks to receive the loops of the bolting cloth, for which purpose they are nicely rounded and smoothed. The ring c is secured by two conical pointed screws to another ring d, placed within c, sufficient space being left between the two rings to allow a small degree of play. The ring d is in like manner secured to the central socket e by means of two other conical pointed screws, with a similar allowance for play; the two rings c and d forming a kind of universal joint. The socket e is put over the square part of the spindle of the reel, and fixed at any part of its length by means of a tightening screw. Fig. 3 represents the improved bolting machine,
with the front pannels of the case in which it is inclosed in order; the beaters hA h/i are fixed, the two which are in front of the machine being shown in dotted lines ; i is the revolving axis or spindle, to which is fixed a light hemi spherical frame in, over which the bolting cloth is drawn, and made fast to the circular ring or curb ri, by means of a string running in a band of leather sewed to the head of the cloth to strengthen it; the loops to the " tail leather" at the other end of the machine are fixed to the spring arms a a, already described and shewn in their place upon the axis i, by which means the most perfect and equal tension of the bolting cloth is obtained, and the beaters being adjusted to a proper distance, the operation of bolting is very effectually per formed. Another improvement, although not claimed in the patent, is the sub stitution of four cloth fanners for the wooden rails, which compose the reel in the ordinary machine. The fanners are constructed as follows: upon the spindle i are fixed two " maces " or bosses k k, from each of which radiate four arms ; from each of the arms on the mace, a piece of duck, about six inches broad, is stretched to the arms of the other mace as shewn at I I. When a rapid motion is given to the reels, the pieces of duck 11 set the air in brisk motion, by which much of the flour is forced through the bolting cloth, the tension and tremulous motion of which, by the elasticity of the springs, tend to prevent the clogging up the interstices of the cloth, and the operation of bolting proceeds with great regularity and expedition. Accompanying the description of the machine in the patentee's circular, are several certificates from respectable millers of its superior efficacy, which state that nearly double the quantity of meal is bolted in a given time. There is another description of dressing machine, in which a cylinder composed of wire gauze of various degrees of fineness is employed to sift the meal instead of a bolting cloth.