2018 年 53 巻 1 号 p. 69-84
High-efficiency continuous processes combining compaction and extrusion for snow disposal using a rectangular cross-section container were investigated for continuous production of large dense cuboid ice blocks from shavings and ice pieces with cube edges of Lice = 8 mm. During compaction, we investigated the ice density and formation pressure and compared them with circular cross-section cubes. Compaction formation pressure Pcomp. obtained using a rectangular cross-section device requires more than 3.50 MPa pressure to produce compacted cuboid ice blocks with ρ = 0.8 g∙cm-3 density. That value is 280% greater than products of a circular cross-section device. Then large ice solids underwent direct extrusion using rectangular cross-section dies for extrusion ratios of R = 1.12–1.30 with α = 90° die angles. The extrusion ratio is the initial cross-section area / final cross-section area of the extrusion container. During extrusion, some relations among extrusion formation pressure and the punch stroke position for each R were investigated to avoid pressure vessel breakage caused by compaction and extrusion. Results show that the proposed extrusion, having strain rate έ ≈ 10-1 S-1, can produce the large cuboid ice blocks. Furthermore, extruded ice blocks of L = 100 mm length, w = 50 mm width, and H = 50–60 mm height were obtained for R = 1.20–1.30.
