Lower ground strata localised freezing system - has refrigerant gas riser within freezing pipe limiting freezing to bottom regions

摘要

The ground freezing system uses pipes which are closed at the top and bottom. Into a freezing pipe is fitted a vertical feed pipe which is open at the bottom. The feed pipe top is connected to the refrigerating gas supply. Freezing of deep ground strata can be carried out without icing of the ground layers nearer the surface. The upper part of the freezing pipe (4) has internal riser pipe (8) which encloses the feed pipe (6). The length of the riser pipe is determined by the upper freezing boundary in the ground. The freezing pipe has a relatively low thermal conductivity in the region of the length of the riser pipe.