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The Carey-Latham machine consists essentially of an arrangement of elevator or dredger buckets, a cement hopper, and a mixing cylinder, The sand and ballast are gathered by the buckets and delivered to the mixing cylinder--the proportion of sand to ballast being regulated by the number or capacity of the buckets employed. The cement or lime is fed from the hopper by an archimedean screw, the pitch or speed of which can be adjusted to suit the quantity required to be delivered in proportion to the sand and ballast. The cement is delivered, says Engineering, in a continuous stream, and together with the load and ballast, which are fed in by the dredger buckets, is passed to the revolving cylinders, where the whole becomes intimately mixed ill the dry state. By the time the materials have arrived at about the middle of the mixing cylinder they have become thoroughly amalgamated, and water is then admitted ill the requisite quantity' by .42 means of a perforated hollow J? I'haft, around which the cylinder \ ,J nsvo)ves. The operation of wet mixing is then performed, and the complete concrete is deliv- ftf!-"sS ered continuously from the open end of the cylinder. An import- JBIfiSM ant feature of the machine is the MKjaSsil arrangement of mixing blades, v?Sf which revolve in the same direction as the cylinder, but at a pafJL slightly different speed; this has ?timPlf!i the effect of increasing the stirring or mixing action, and over- wW'MM comes a difficulty which was SsSfl found to exist by the setting of the cement when fixed blades 1 were employed. The blades in ESzlllbsirTfr:;:::::: moving at a quicker speed con- lCr'"--drsll'"i stantly change their position TzfJSr: ? with respect to the inside of the cylinder, so that no cement can accumulate and set upon them. The cylinder is horizontal, but as the blades are of a cu rved or screw-like form, the materials are lifted and tumbled over and over, and at the same time forced toward the open end of the cylinder, At the Newhaven Harbor Works, two of Carey&Latham's machines have been employed in making over one million tons of concrete; but numerous improvements have since been effected in them, and the machine we illustrate differs in several material points from the former pattern. It. is now constructed in various sizes suitable for making five to seventy cubic yards per hour, and we understand Messrs. Ingrey, Poore&Latham, London, have supplied several of 20 yards and 70 yards capacity to some of our large contractors.
