Work was done in the 1970s with developments such as the zero
metering screw in an effort to improve on the standard model.
The extruder had an L/D = 22 and was equipped with a conventional feeding and
metering screw with a channel depth at the metering end of 2 mm.
The vibrator conditions and tends to force feed the bulk material into flights of the
metering screw where a close trough radius makes it self-cleaning.
The remainder of this article will cover the precision
metering screw insertion method.
A 4.5-in., square-pitch
metering screw with a channel depth of 0.3 in.
The plant already has three lime presses and Robsons are installing a further two, complete with structural works and
metering screw conveyors to transfer the dewatered lime cake on to the main conveying system.
A single screw extruder was used to study the effect of the
metering screw section geometry i.e., the shearing on the pulverization.
4 as melt temperature versus output rates--demonstrate a temperature advantage for the double
metering screw. This screw was used to determine the influence of extruder size on melt temperature.
Two screws were employed: (a) a Davis-Standard
metering screw without a Maddock mixing head and (b) a Davis-Standard barrier screw with a Maddock mixing head.
For the same blend, using a
metering screw, 1.0 mm die exit gap, and 270 [degrees] C temperature results in lamellar morphology.
It is then fed by a
metering screw into the two-stage Munchy recycling extruder.
An objective of this paper is to report the findings on the effect of a single stage
metering screw and the melt temperature and pressure variations on the thermal and rheological properties of nylon 66 and acetal materials.