Abstract: The cable C to be stripped is wound with non-touching coils and crossed layers of cable onto a drum 6 having a perforated core 10 rotatively mounted in a thermally insulated container 1. By injecting into the container liquid nitrogen under the control of a temperature sensor and by circulating the gases contained in the container through the core of the drum and the cable coils, the whole of the cable is cooled down to a temperature at which the plastics coating and, as the case may be, the outer steel sheath of the cable become brittle. The cable is then unwound and, when it has left the container, it is subjected to various mechanical stresses. The stripped cable is finally wound onto a take-up reel 3. Application in the recovery of scrap in the manufacture of power cables of large diameter and recovery of used electric cables.

Abstract: The region 1 to be cooled contains the evaporator of a heat pipe 2 which contains a diphase fluid adapted to the desired temperature between about 0.degree. and -100.degree. C. The condenser 7 of the heat pipe is cooled to a set temperature by a copper ring 8 which is cooled by a regulated liquid nitrogen current. Applications in the freeze trapping of solvents contained in a gaseous current.

Abstract: The invention relates to a method of producing sand castings in which a set of castings incorporating the casting runners and risers is formed.The castings, which are cast in pairs to form compact members, are placed in baskets and are subjected to refrigeration firstly in a precooling zone and then in a dipping zone in a liquid nitrogen tunnel. After this the compact members are placed on a breaking-up table where they are subjected to mechanical shocks to enable the castings to be separated from their casting risers and runners.Applicable exclusively to "as cast" ductile cast iron.