530 



BEICK 



architect or builder than for the brick-maker. Perforated bricks are a fifth less in 

 weight than solid ones, which is a matter of some importance in transit; but it takes 

 considerably more power to force the clay through those dies than for solid brick- 

 making. In the manufacture of perforated bricks, there is also a royalty or patent- 

 right to be paid to Mr. Beart.' 



Mr. Chamberlain's own machine is in principle as follows (fig. 260) : The clay is 

 fed into a pug-mill, placed horizontally, which works and amalgamates it, and then 

 forces it off through a mouth-piece or die of about 65 square inches, or about half an 

 inch deeper and half and inch longer than is required for the brick, of a form similar 

 to a brick on edge, but with corners well rounded off, each corner forming a quarter of 

 a 3-inch circle, for clay will pass smoothly through an aperture thus formed, but not 

 through a keen angle. After the clay has escaped from the mill it is seized by four 

 rollers, covered with a porous fabric (moleskin), driven at a like surface speed from 

 connection with the pug-mill. These rollers are two horizontal and two vertical ones, 

 having a space of 45 inches between them; they take this larger stream of rough 

 clay, and press or roll it into a squared block, of the exact size and shape of a brick 

 edgeways, with beautiful sharp edges, for the clay has no friction, being drawn through 

 by the rollers instead of forcing itself through, and is delivered in one unbroken 

 stream. The rollers in this machine, perform the functions of the die in one class of 

 machinery, and of the mould in the other. They are, in fact, a die with rotating 

 surfaces. By hanging a series of mandrels or cores between these rollers, or by 



merely changing the mouth-piece, we make hollow and perforated bricks, without any 

 alteration in the machine. 



Messrs. Bradley and Craven, of Wakefield, have invented a very ingenious brick- 

 making (fig. 261) machine : 



It consists of a vertical pug-mill of a peculiar form, and greatly improved construc- 

 tion, into the upper part of which the clay is fed. In this part of the apparatus the 

 clay undergoes the most perfect tempering and mixing, and on reaching the bottom of 

 the mill, thoroughly amalgamated, is forcibly pressed into the moulds of the form 

 and size of bricks required, which are arranged in the form of a circular revolving 

 table. 



As this table revolves, the piston-rods of the moulds ascend an incline plane, and 

 gradually lift the bricks out of the moulds, whence they are taken from the machine 

 by a boy, and placed on an endless band which carries the bricks direct to the waller, 

 thus effecting the saving of the floor room. 



The speed of the several parts of the machine is so judiciously arranged, that the 

 operations of pugging, moulding, and delivering proceed simultaneously in due order, 

 the whole being easily driven by a steam-engine of about six-horse power, which, at 

 the ordinary rate of working, will make 12,000 bricks per day ; or, with eight-horse 

 power, from 15,000 to 18,000. 



In consequence of the perfect amalgamation of tho clay, and the great pressure to 

 which it is subjected in the moulds, tho bricks produced by this machine are perfect ; 



