Sorting feed system

All the systems must have a means of bringing the solids and the gas stream together. Since the gas is under either vacuum or pressure, some sort of airlock is needed in order to prevent air either from being sucked into the system or from being blown into and through the feeding system. The most common solution is a rotary valve (see Fig. 8-9) driven by a motor. 

The product feeding system in a sorting machine should provide three basic functions ... 

To detect small blemishes on frait and vegetables reliably, it is necessary to inspect the product from two sides. The traditional architecture of an optical sorting machine is to feed the product along a horizontal conveyor and then observe the product from top and bottom views as the product flies off the end of the conveyor. The drawback with this approach is that the bottom camera is soon covered in product. The Sortex Niagara machine overcomes this problem with the PowerShde feed system (Fig. 6.14). The belt conveyor on the Niagara is inclined at 60° to the horizontal, such that the cameras can view the product from either side, and remain clean. This novel feed mechanism is known as the PowerSlide and is patented by Sortex. 

Sorting and feeding devices are tm important component in the automated assembly of products. Their task is to sort out the often unsorted supplied workpieces and to deliver the tight amount to the assembly station at the tight time. The most commonly used feeding systems are vibratory bowl feeders, capable of sorting nearly 90% of all components automatically. 

A commonly made mistake in these two-reactant feed systems is to assume that a control structure with one feed ratioed to the other will provide effective control. This scheme does not work because of inaccuracies in flow measurements and changes in feed compositions. Remember in neat operation the reactants must be balanced down to the last molecule. This can only be achieved by using some sort of feedback information from the process that indicates a buildup or depletion of reactant. 

As a final example of fitting SCAT data, Fig. 16 shows experimental data and SCAT model prediction for a more complicated gas mixture including CO, C3H6, NO and 02. Once this sort of fit is achieved for a series of different feed compositions, the kinetics are ready to be added to the model of a monolith reactor and tested against data for a real system. 

The various feeding and sorting systems are depicted in Figure 29. 

Another example is a system made by National Recovery Technologies (NRT) Inc. (Nashville, TN) [72]. This apparatus incorporates a proprietary electromagnetic screening process that also detects the presence of chlorine as found in PVC bottles. Once detected, PVC bottles are pneumatically jettisoned from the commingled bottle feed stream by a microprocessor-based air-blast system. The NRT technology permits bottles to be delivered to the unit in a mass sort concept in either crushed or whole form. This system does not require any special positioning or orientation of the bottles in order to achieve high efficiency rates. 

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