Solid bucket elevators

The Bollman-type extractor shown in Fig. 18-76 is a bucket-elevator unit designed to handle about 2000 to 20,000 kg/h (50 to 500 U.S. tons/day) of flaky solids (e.g., soybeans). Buckets with perforated... 

Where a vertical lift is required, the most widely used equipment is the bucket elevator, consisting of buckets fitted to a chain or belt which passes over a driven roller or sprocket at the top end. Bucket elevators can handle a wide range of solids from heavy lumps to fine powders and are suitable for use with wet solids and slurries. 

There are many other different types of solids-handling devices, ranging from dumpsters to screw and belt conveyors and bucket elevators. The range and variety of equipment make this subject too large to be adequately covered by this book. The reader is referred to the voluminous literature on the subject. For sizing equipment the most helpful source is often the manufacturers manuals. 

The rubber belt of a bucket elevator, fitted with aluminium buckets and used for transporting solid chlorate, jammed during use. Friction from the rotating drive pulley heated and powdered the jammed belt. A violent explosion consumed all the rubber belt and most of the 90 aluminium buckets. Bronze and steel equipment is now installed. 

The cattle manure with about 25 p.c. dry matter content and the litter is transported by trailer to the reception hopper for manure and solid organic wastes. From here manure will be delivered by a bucket elevator, with the help of feed screw conveyor into the digester tower made of anticorrosive steel. The slurry and the sewage water mixed with faeces will be pumped into the digester. 

Fig. 21. Production diagram of silicon tetrachloride by ferrosilicon chlorination 1 - jaw crasher 2 - bucket elevator 3 - grate 4 - shaft hoist 5 -bin 6 - chlorinating furnace 7 - condenser 8 - scrubber 9 - boiler 10, 14 - condensers 11 - distillation tank 12 - rectification tower 13 - refluxer 15 -collector 16- apparatus for the destruction of solid chlorides 17- hydrolysis chamber 18- absorption column.

Materials-handling equipment is logically divided into continuous and batch types, and into classes for the handling of liquids, solids, and gases. Liquids and gases are handled by means of pumps and blowers in pipes, flumes, and ducts and in containers such as drums, cylinders, and tank cars. Solids may be handled by conveyors, bucket elevators, chutes, lift trucks, and pneumatic systems. The selection of materials-handling equipment depends upon the cost and the work to be done. Factors that must be considered in selecting such equipment include ... 

Bucket elevators, skip hoists, and cranes are used for top feeding of the furnace. Retention and downward flow are controlled by timing of the bottom discharge. Gases are propelled by a blower or by induced draft from a stack or discharge fan. In normal operation, the downward flow of solids and upward flow of gas are constant with time, maintaining ideal steady-state conditions. 

Continuous Percolators Coarse solids are also leached by percolation in moving-bed equipment, including single-deck and multideck rake classifiers, bucket-elevator contactors, and horizontal-belt conveyors. 

HANDLING OF BULK SOLIDS AND PACKAGING OF SOLIDS AND LIQUIDS TABLE 21-9 Bucket-Elevator Specifications for Continuous Buckets on Chain ... 

The Bollman-type extractor shown in Fig. 18-85 is a bucket-elevator unit designed to handle about 2000 to 20,000 kg/h (50 to 500 U.S. tons/day) of flaky solids (e.g., soybeans). Buckets with perforated bottoms are held on an endless moving belt. Dry flakes, fed into the descending buckets, are sprayed with partially enriched solvent ( half miscella ) pumped from the bottom of the column of ascending buckets. As the buckets rise on the other side of the unit, the solids are sprayed with a countercurrent stream of pure solvent. Exhausted flakes are dumped from the buckets at the top of the unit into a pad-... 

Most nuclear wastes are in liquid or solid form. If the waste is solid, it may be transported by various methods in drums using forklifts, on conveyor belts, suspended in gases in pneumatic conveyors, suspended in liquids as slurries, in screw conveyors, in bucket elevators, etc. 

Although waste is considered as a material, in fact it is a mixture of materials, each one having its own handling characteristics, somehmes entirely different than those of the other components. There are several handling systems used to convey solid waste. The most widely used are steel plate, belt and vibrating conveyors, bucket elevators, and pneumatic systems. 

CONVEYORS. Pneumatic conveyors for solids are described in Chap. 7. Other common devices for transportation include belt conveyors and bucket elevators, closed-belt conveyors with zipperlike fasteners, and various kinds of drag and flight conveyors. These all include a return leg that carries the empty belt or chain back from the discharge to the loading point. Vibrating conveyors and screw conveyors have no return leg but only operate over relatively short distances. Pneumatic conveyors also have no return leg and are not so limited as to distance of travel. Conveyors for solids are discussed in Ref. 9a. 

Solids (belt conveyor— bulk or discrete flow, pneumatic conveyor—bulk or discrete flow, screw conveyor—bulk or discrete flow, bucket elevator—bulk or discrete flow)... 

Heuristic 48 If the solid particles are small in size, low in particle density, and ore not sticky or abrasive, use pneumatic conveying with air at 1 to 7 jf/ff of solids and 35 to 120 ft/s air velocity for distances up to 400ft. Otherwise, for sticky and/or abrasive solids of any size and density, use a screw conveyer and/or bucket elevator for distances up to 150 ft. For solid particles of any size and shape, and not sticky, use a belt... 

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