| 摘要 |
<p>The appts includes a porous member with through porosity. The porous member fills a second section of a duct adjacent to a honeycomb member (30) oppositely from the working surface. A plenum (36) is delimited in a duct (26) adjacent to the porous member (34) oppositely from the honeycomb member. A gas device is connected to supply the plenum with a dry gas at a gas pressure selected co- operatively with the porosity. The spacing, the cross section and the aspect ratio effect a flow of gas through the porous member and the honeycomb member with a gas velocity such that a laminar curtain of the gas is effected across the cryogenic working surface (18). The honeycomb is formed of the multiplicity of cells (32) each having a through channel (52) in the longitudinal direction. The cells are identical. A material for the honeycomb is not critical, but should be corrosion resistant, for example a stainless steel. The length of the honeycomb cells through the duct may be, for example, 1.6 cm.</p> |
