| 摘要 |
A roller having a multiplicity of open moulding cavities on its surface, the roller being hollow with its cavity being partially filled with liquid nitrogen, characterised in that: A vacuum insulation compartment is located on each side of the roller; The vacuum insulation compartment, in radial cross section, presenting an outside generally plane and circular wall in the form of an annular disc, joint to a roller side wall by two portions having: a general sigmoid cross section for the portion at the peripheral part of the vacuum panel; a general sigmoid cross section for the portion at the central part of the vacuum panel. |
