Abstract: The rectifier is formed by two concentric pipes which are disposed to define a counter-current flow path and a plurality of spherical calotte-shaped or similar indentations in the outer pipe. The indentations are formed simultaneously in staggered rows (1) to divide the flow path into a plurality of small parallel passages and (2) to secure and fix the mutual position of the two pipes relative to each other. The cross-sections of the formed passages have a maximum linear dimension of five millimeters (5 mm.).

Abstract: A simplified refrigeration apparatus in which the evaporator part includes a straight, generally horizontal pipe system that is connected to a linear continuation forming a gas heat exchanger. The assembly is inserted in the cooling chamber of a refrigerator through an opening in the insulated refrigerator cabinet. The gas heat exchanger is positioned within said insulation while the evaporator part is projected into the interior of the cooling chamber. The assembly permits the easy removal from the refrigerator cabinet, when desired, and is of compact construction lending itself to requirements of a small refrigerator.