Solid vibrating conveyors

Vibrating-conveyor dryers are suitable for free-flowing solids containing mainly surface moisture. Retention is limited by conveying speeds which range from 0.02 to 0.12 m/s. Bed depth rarely exceeds 7 cm, although units are fabricated to carry 30- to 46-cm-deep beds these also employ plate and pipe coils suspended in the bed to provide additional heat-transfer area. Vibrating dryers are not suit le for fibrous materials which mat or for sticky sohds which may ball or adhere to the deck. 

Vibrating conveyors employing direct contacting of solids with hot, humid air have also been employed for the agglomeration of fine powders, chiefly for the pr aration of agglomerated water-dispersible food products. Control ofinlet-air temperature and dew point permits the uniform addition of small quantities of liquids to solids by con-... 

The vibrating conveyor dryer is a modification of the fluid bed free-flowing solids greater than 100 mesh having surface moisture ... 

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. 

For conveyor dryers, the wet feed is carried on a belt or a vibrating conveyor that is made to pass slowly through a heating chamber. Depending upon the design, hot air may or may not pass through the bed of solids on the conveyor. 

Vibrator type — a tray in which the bottom and one end curves up gently to be level with the top edges of the sides. An attached vibrator breaks up the solid and shakes it over die curved end of the tray to a discharge conveyor. Cakes may be up to 3 inches thick... 

For instance, the glass tube must always be full of solids with a constant flow. To ensure this, the end of each tube was squeezed and the bottom of these tubes were placed at a short distance from a conveyor belt operating at constant speed (5 m min-1), thus gently deposing the mixture as a layer onto the belt. This set up also allows a validation of the method by comparing the sample compositions in the belt to the compositions given by the closest sensor. With this special set up, all particle flow rates become quickly equal from the vibrating channel to the conveyor belt (in fact, the amplitude of the vibrations can be adjusted for this task). 

Equipment can handle nonfluidizable solids fractions. Although these fractions may drop through the bed to the screen, directional-throw vibration will cause them to be conveyed to the discharge end of the conveyor. Prescreening or sizing of the feed is less critical than in a stationary fluidized bed. 

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