Axial pressure profiles

Figure 1.6 Axial pressure profiles for a) Example 2 where the extruder is operating properly (all channels are full and pressurized), and b) Example 3 where the extruder is operating improperly. For Example 3, the channel is not pressurized between diameters 12 and 22, indicating that the channels are partially filled at these locations...

Figure 6.5 Axial pressure profiles measured for the screws used to make the cross sectional photographs in Fig. 6.4... 

Figure 6.7 Axial pressure profiles measured for a 63.5 mm diameter extruder running an ABS resin at 60 rpm for screws with a 8.89 mm deep feed channel, 6 diameters of feed section, and a metering channel depth of 3.18 mm (C = 2.8) for the photographs of Fig. 6.6...

Figure 6.8 Axial pressure profiles for the screw with a compression ratio of 2.4 running ABS resin as a function of screw speed... 

Figure 6.19 Simulated axial pressure profile for a 63.5 mm diameter screw. The pressure at the entry to the transition section was assumed to be 3 MPa. Melting was completed by diameter 13.7...

Figure 6.38 Axial pressure profiles for a 63.5 mm diameter instrumented extruder running two different pellet geometries at a screw speed of 90 rpm...

Figure 7.16 Simulated axial pressure profile for a 500 mm diameter extruder running 11,800 kg/h at 46 rpm for the 0.8 Ml LDPE resin. The experimentally determined pressure at 5.6 diameters was 6.4 MPa...

Figure 10.15 Axial pressure profiles for the EIDPE resin at Zone 1 (Z1) temperatures of 170 and 230 °C...

Diagnosing and eliminating a problem that occurs due to an improperly operating extruder can be difficult and time consuming. This section contains several case studies where improperly designed processes created contamination defects in the final articles. The axial pressure profiles of the metering channels for these case studies and other studies in the next chapters were calculated using the method described in Section 9.2.1. The simulated axial pressure profiles are shown with solid lines while the estimated pressure profiles are shown by dashed lines. 

Figure 11.21 Axial pressure profile for the barrier screw after the screw modification. All sections of the screw are filled and operating under pressure. The solid line in this figure was calculated using the methods described previously, and the dashed line represents the expected pressure profile and was not calculated...

Figure 11.24 Simulated axial pressure profile for the 152.4 mm diameter screw running HOPE resin in a high-speed blow-molding application...

Figure 11.31 Axial pressure profile for the injection-molding screw described in Table 11.11 at a rate of 340 kg/h, a screw speed of 99 rpm, and a discharge pressure of 25 MPa...

Figure 13.5 Axial pressure profile for the original screw operating at 204 kg/h, 32 rpm, and a discharge pressure of 18 MPa. The dotted line was estimated and the solid line was calculated...

Figure 13.13 Simulated axial pressure profile for the 203.2 mm diameter reclaim extruder discharging PS resin at a rate of 410 kg/h at a screw speed of 37 rpm...

In using this friction factor for a tubular reactor, the Reynolds number is evaluated at Borne estimated average condition, and then the corresponding friction factor is used for the whole bed. In calculating the axial pressure profile, the average composition and temperature in a cross section are used to estimate the density of the fluid, and this density is used with the average superficial mass velocity to estimate the axial derivative of pressure. 

Figure 10. Axial pressure profiles observed at steady state for initial drainage experiment (no prior imbibition) and final drainage experiment (after a number of successive drainage and imbibition experiments).

Accepting this concept, the present problem is conveniently formulated as one of laminar flow through a circular tube. The axial pressure profile and flow rate are identified as the key macroscopic variables. 

Data on the time-dependent flow of foam through the test section (c.f. Fig. 1) consists of continuous records of the axial pressure profile, and of foam rise in the overhead reservoir. (An example is given in Fig. 2.)... 

The fact that the axial pressure profile is linear over a relatively broad time interval is extremely important. Most probably, it indicates that under the present experimental conditions ... 

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