Barrel segment

Customized and flexible screw-element and barrel segment designs, and fast and efficient melting and mixing (both dispersive and distributive) in most TSEs make such equipment very well suited and almost exclusively used for the following polymer processing operations ... 

Fig. 10.57 Typical 4 LID Co-TSE barrel segments, (a) Feed throat (b) melting (c) downstream feed section (d) mixing (e) devolatilization (f) pumping and limited pressurization. [Courtesy of P. Andersen Coperion Wemer and Pfleiderer, Ramsey, NJ.]...

Fig. 13.31 Friction stir weld process development tool at the Marshall Space Flight Center (MSFC) shown with an 8.2 m (27 ft) diameter barrel segment of the 2195 Al-Li Space Shuttle external tank LH2 tank (left). Full-scale LH2 tank (right) at the National Aeronautics and Space Administration (NASA) Michoud Assembly Facility in New Orleans. Courtesy of NASA MSFC...

Figure5.12 (a) Modularscrew typical4 L/DCO-TSE barrel segments (b) feed throat, (c) melting, (d) downstream feed section, (e) mixing, (f) devolatilization, and (g) pumping and limited pressurization. Courtesy of Coperion Werner Pfieiderer.

Tests were done on two barrel segment sizes using an array of twelve (12) thermocouples installed on the length-wise centerline of each barrel. Pairs of these thermocouples were installed at six (6) incremental depths, progressing from the outside surface to the bore. Both MICA-style and ceramie-style band-heaters were tested on each barrel size, as follows ... 

Band-heater efficiency as a function of operating temperature was assessed by computing the internal energy change of the barrel segment each time increment (simple finite difference analysis with six annular elements). Tests with the MICA-style band-heaters were first done when the barrel and heaters were new (and therefore produced minimal radiant heat losses), then repeated after about six hours once the barrel and heater surfaces had substantially discolored and darkened (after about six hours of use), and then finally after painting the barrel and heater surfaces matt-black to maximize radiant heat losses. 

The barrel-segment tests explained why control was superior with induction dining the molding machine tests. Figure 7 shows the energy inpnt to the 89 mm OD barrel was virtually immediate with induction, and when power was turned off, heat inpnt to the barrel ceased immediately. Fnrthermore, becanse heat losses to ambient were insignificant, the power inpnt was never negative. 

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