In addition to the benefits of height gains and dismantling ease, the innovative design allows dust extraction to be provided by a continuous circular channel
on the spiral's outside circumference with a compressed air in-feed from the center channel.
This circular channel
was attached to a control gate and a discharge tank through another direct channel which was 5.
The working volume of the loading unit was simplified assuming it as a parallelepiped with a cross-section corresponding the size of moving plate in hydraulic loading unit (55x60 mm), and consisting of two 100 mm length chambers, separated by the diaphragm having a changeable diameter circular channel
(from 3 to 12 mm).
Figure 8 shows a cross-section cut of polystyrene taken near the end of the circular channel
To avoid discretization of the circular channel
along the circumference, which would require a lot of small triangular shell elements, and thus save a substantial amount of computer memory, the so-called line source (sink) approach first developed by Barone and Caulk  and further extended by Rezayat and Burton  for cooling channel simplification in three-dimensional parts was implemented.
Five different die channel geometries were used in this study; a square channel, a rectangular channel, a teardrop shaped channel, a circular channel, and a rectangular manifold channel.
Since the circular channel is radially symmetric, very little layer rearrangement was expected to occur.
Approximately 930 m circular channel
, about 190 pcs.
Extrudate swell from the square channel approaches its limit much more rapidly with increasing surface tension than does that from the circular channel
This range includes: trenchless renovation of circular channels
with a diameter of dn 300 - 600 mm and channels eggshaped with dimensions 200/300 - 400/600 mm with a total approximate length l = 1641.