Conveyor flights

Ks dependent on composition, 377 Flight conveyors, 81 Flocculants, 309 Flocculation, 351... 

Table 9.—Economic Speeds for Flight Conveyors Handling Various Materials...

Formulas for ascertaining the capacity of flight conveyors with rectangular flights equally spaced and the conveyors economically and continuously loaded are ... 

Power Requirements,— The consumption of power in operating flight conveyors is materially affected by whether the flights are mounted on sliding shoe or roller flights. Formula (12) by the use of the proper constant permits the calculation of power requirements in either event. 

Depreciation varies greatly in the case of flight conveyors as both the flights and the trough are subject to severe abrasive action by the material with which they are in contact in operation. Virtually every material varies in its destructive action. With Formula (14), depreciation factors for some of the materials commonly handled by flight conveyors are given. 

Fixed charges for flight conveyors may be taken, as in the case of belt conveyors, at 8.5 per cent per year, but in addition there is an annual renewal charge amounting to about 20 per cent of the initial cost. 

The respective net costs of operating the two types of flight conveyors differ to some extent, as will be noted in the following example. 

Speeds for bucket carriers with rigid buckets may run as high as those employed for flight conveyors, but carriers with pivoted buckets should rarely be run at a speed greater than from 50 to 75 ft. per minute on account of the shock developed when dumping the buckets. Advisable speeds for pivoted bucket carriers when handling various materials are given in Table 12. 

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. 

The main variables for selection and design of scraper conveyors are the capacity and the power. The capacity of horizontal scraper conveyors loaded with materials of approximately 800 kg/m bulk density, has been calculated and is presented in Table 3.8. The theoretical horsepower requirement P for flight conveyors can be determined from the following equation ... 

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