Continuous circulation band

Conveyor dryers (continuous circulation band dryers) (Figure 10.26)... 

Conveyor Dryers (Continuous Circulation Band Dryers)... 

Continuous Through-Circulation Band Dryers Continuous... 

Bucket elevators. The bucket elevators lift catalyst, at 900-1000°F., about 200 ft. Each elevator consists of two chains with a continuous line of alloy-steel buckets loosely supported between them (217). The upper shaft is fixed in position but the bottom shaft can move to offset thermal expansion and wear of the chain. Chain speeds are 90 to 125 ft./minute at catalyst-circulation rates of 100 to 150 tons/hour. Power requirement is 60 to 80 horsepower (241). Differential band brakes protect against reverse rotation in case of a power failure. Sprockets with renewable teeth were used at first (217), but a traction-wheel drive was later substituted because wear is more evenly distributed and life is longer (241). Repair techniques have been developed for extending chain life (316). Graphite is used to lubricate the chains (239). The upper shaft and main bearings are water-cooled and the bearings are lubricated with oil. 

Continuous band/tunnel Particulate Tunnel Cross-circulation Moving truck/trolleys... 

Design Methods for Continuous Band Dryers In actual practice, design of a continuous through-circulation dryer is best based upon data taken in pilot-plant tests. Loading and distribution of solids on the screen are rarely as nearly uniform in commercial installations as in test dryers 50 to 100 percent may be added to the test drying time for commercial design. 

Performance and Cost Data for Continuous Band and Tunnel Dryers Experimental performance data are given in Table 12-21 for numerous common materials. Performance data from several commercial through-circulation conveyor dryers are given in Table 12-22. Labor requirements vary d ending on the time required for feed adjustments, inspection, etc. These dryers may consume as little as 1.1 kg of steam/kg of water evaporated, but 1.4 to 2 is a more common range. Thermal efficiency is a function of final moisture required and percent air recirculation. 

The microwave circuit used in this study is shown in Figure II. The Gerling-Moore variable 0-2.5 kW power generator operates at 2450 MHz. Three crystal detectors in the circuit measure forward, reflected, and transmitted power and are mounted in the S-band wave-guide (3.8 x 7.6 cm). The latter two power measurements are recorded continuously. Constant forward power and magnetron protection are ensured by the presence of a 3-port circulator. The impedance of the circuit is manually matched with the E-H field tuner. The reactor is placed through the wave guide as shown. 

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