Solids conveying device

Two solids conveying devices were built at the Clarkson Polymer Extrusion Consortium. The first device was used to visualize the flow in the section without a discharge pressure. The second device was built such that a relatively high discharge pressure could be applied to the process. 

Figure 5.4 Polymer pellet motion in a single screw. The zero pressure solids conveying device at Clarkson was used for these experiments...

Figure 5.6 Schematic of the solids conveying device at Clarkson with the capability of applying a pressure at the discharge end of the device...

Figure 5.7 Photograph of the Clarkson solids conveying device. The device is sho A/n schematically in Fig. 5.6...

The barrel floats" on the screw, rather than being permanently affixed to the frame of the device itself. This facillitates the measurements of barrel torques and thrusts as a function of operating conditions and the type of polymer being conveyed. Fig. 5.9 schematically details the extruder section of the solids conveying device and the instrumentation location [10]. Dark red arrows indicate force measurements, and light yellow rectangles represent temperature and heat flux measurements. A total of five force devices allowed the measurement of the screw... 

Figure 5.11 Solids conveying as a function of discharge pressure for HDPE and PS resins using the Clarkson solids conveying device. The data were collected at a screw speed of 50 rpm and barrel temperatures of 24 and 35 °C for the HDPE and PS resins, respectively. The temperature of the screw was maintained at the temperature of the barrel...

Figure 5.17 Photographs of sintered PS resin masses a) from the discharge end of the solids conveying device, and b) mass removed from the screw...

The solids conveying device at Dow was built from a standard 63.5 mm diameter extruder. It was built by replacing the standard barrel with a short barrel, providing an L/D ratio of 4.5. The feed hopper casing had an effective barrel length of 1.9 diameters and was water cooled. The feed opening was 1.5 diameters in length ... 

Figure 5.20 Photographs of the solids conveying device at Dow a) full view of the device, and b) the pressure discharge unit. Pellets were discharged through an annular opening between the discharge (matched) plate and the torpedo...

Table 5.1 Experimental Solids Conveying Rates (Fig 5.24) as a Function of Discharge Pressure at a Screw Speed of 50 rpm and Barrel and Screw Temperatures of 75 °C for the LDPE Resin. Data were Collected Using the Shallow Screw for the Dow Solids Conveying Device...

Figure 12.29 Schematic of the laboratory solids-conveying device with the ledge plate installed...

Table 12.7 Ledge Sizes and Flight Clearances in the Feed Casing for the 63.5 mm Diameter Laboratory Solids-Conveying Device...

Figure 12.30 Modification to remove the ledge for both a) the solids-conveying device and b) a commercial extruder...

Table A5.1 Channel Dimensions for the Shallow and Deep Screws for the 63.5 mm Diameter, 4.5 L/D Solids Conveying Device at Dow...

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