230 REPORT— 1871. 



numerous, do not reach to the centre of the machine ; this part is unoccupied by studs, 

 and acts as an " eye " to receive the feed. The first two or three rings ot studs, 

 heginning- at the centre, are fixed to one of the disks only, viz. the one opposite to 

 that through which the feed enters, and they serve to distribute that feed equably 

 throughout the machine. So soon as the material has, however, passed by cen- 

 trifugal force beyond the limit of the outermost of these central or " eye "- 

 rings, it is met by the first of the rings moving in the opposite direction. The 

 studs of this ring find the material while in mid air and moving in a direction 

 opposite to their own motion, and with a velocity due to the circumferential speed 

 of the ring of studs the material has just qmtted. The result of this meeting ia 

 clearly, first a violent blow, and then a reversal of motion, by which the whole of 

 the material is sent flying through the air in a "direction contrary to that which it 

 last had, and with a velocity increased by the increased circumference of the ring 

 of studs which has just put it into motion, a velocity and a direction, however, to 

 be aU but instantly arrested and reversed by the action of the next ring of studs, 

 and so the material proceeds from ring to ring until it is delivered, completely pul- 

 verized, at the circumference of the machine. It will have been gathered from 

 this description tliat a Carr's Disintegi-ator acts to reduce material upon a prin- 

 ciple wholly different to those principles upon- which millstones, edge-ruuners, 

 crushing-rolls, rumblers, and stampers act ; in fact, so far as the writer of this 

 paper is aware, upon a principle which had never been applied to a similar or even 

 to an analogous purpose, and that principle is the breakmg up of the material by 

 the action of a force which has no other abutment, if the term may be used, than 

 the momentum of the material itself. In fact the material is treated as a shuttle- 

 cock, to be bandied backwards and forwards between mechanical battledores, 

 Suffering breakage at each blow until it is reduced to the required condition of 

 pulverization. 



The proportions of the machine and the size of the spikes or studs are varied to 

 suit the material to be operated upon. 



The particidar machine upon which the experiments (the subject of this paper) 

 were made is used for converting wheat into flour. It is about 7 feet diameter, 

 and has a space of 10 inches between the faces of the two disks. The disk 

 on the feed side carries six concentric rings of studs, which work between 

 six concentric rings on the opposite disk. This opposite disk has also three 

 " eye "-rings. The studs are circular, half au inch in diameter, and made of 

 crucible steel. The distance fi-om centre to centre of the studs is 2^ inches, 

 and from ceuti-e to centre of the rings also 2^ inches, so that there is a clear 

 space both circimiferentially and radially of 2 inches between the studs. The re- 

 volving disks are enclosed in a casing, at the bottom of which there is an ordinary 

 creeper or screw to convey away the meal produced ; and as now very commonly 

 appUed to the cases of millstones, there is an exhaust-pipe connected with an 

 exhaust-fan, to remove the dust and convey it to a depositing chamber, the " stive " 

 room. The machine is driven from a counter shaft by means of two sh-aps, one 

 open, the other crossed, so as to give motion in opposite du-ections to the two 

 disks. Their ordinary working speed is about 400 revolutions per minute. 



By the gi-eat courtesy of Messrs, Gibson and Walker, and with the able assist- 

 ance of theii- engineer, Mr. Watson, the ^^liter and Mi: Edward Easton wci-e 

 enabled to make the following experiments to test the power required to drive this 

 machme imder varying circimistances. In arranging the programme of these ex- 

 periments, the writer was particulaiiv desirous of ascertaining whether or not a 

 siispicion he entertained as to a source of consumption of power in the working of 

 the machine was justified by the facts. Frotn a consideration of tJie number of 

 times the disks revolve in a minute, and of the number of rings of studs, it is clear 

 there must be many thousand settings into motion, and reversals of those motions, 

 per mmute of any material within the action of the disks ; and it occurred to the 

 writer that although the air within the zone of action of the machine weighed only 

 between 30 and 40 omices, yet even that trifling weight could not be subjected to 

 such treatment without the consumption of a very considerable amount of power. 

 He therefore determined to ascertain the power requii-ed, not onlv when the 

 machine was working in its normal manner, both with and without ieed, but also 



