THE MECHANICAL HANDLING OF MATERIALS 323
flanged rollers. Suitable tension gear, as described on page 309, is provided for taking up any extension of the chain. A chain. of the De Brouwer type will deal with from 50,000 to 60,000 tons of coke during its working life. The speed of travel of the conveyor is low, averaging about 40 feet per minute.
A somewhat similar type of hot-coke conveyor, but one in which a different type of chain is employed, is shown in Fig. 235. Dempster’s hot-coke conveyor is another familiar pattern. As will be seen from Fig. 236, it is of the rake type, and is so arranged that only the rakes are in contact with the coke, all the moving parts being on an elevated pathway and screened from the coke by means of baffle plates. Thus the chains and sliding shoes are clear of both coke and quenching water. The trough is formed of channels and Z-steel sides with steel bottom plate. The inside of the trough is provided with cast-iron liners and steel flat-bars on the Z-sections for the chain shoes to run on. As in the otter types of conveyors the return can be arranged o ver head if so desired. The chains are entirely formed of low carbon steel to prevent corrosion by acid fumes, etc., evolved by the coke during quenching. The rakes are of malleable iron, and the sliding shoes of chilled cast-iron.
Drake’s Tray Conveyor
This hot-coke conveyor is unique in that it embraces the principle of carrying the coke and not dragging it. The general construction is shown in Fig. 237, from which it will be seen that the conveyor consists of corrugated trays mounted on
Fig. 237.— Dkake’s Tkay Hot-Coke Conveyor.
wheels, and running in a cast-iron trough. There is in reality no wearing part with the exception of the wheels. which revolve upon a fixed pin. The comiection between the trays is also by a pin, which acts as an axle when the trays are running roiind the drum, ready for the return. The trough. is fitted with curtain plates which overlap the inside of the tray and which prevent the coke from getting over the side and into the patli of the wheels.