Abstract: This invention relates to a trapping tube characterized in that it is constituted by a shaped tube comprising:a first section or zone of condensation of the separated gaseous phase delivered by the outlet of the chromatograph,a second section or zone of confinement of the condensate of the separated gaseous phase,and a third section or zone of evacuation of the vector gas of the separated gaseous phase. The invention is more particularly applicable to the obtaining of condensates in a small, even infinite quantity.

Abstract: Elongated steel tubes are grouped together and bound into bundles with bing sufficiently tight that there is no clearance or play between the tubes during heat treatment. Such binding provides a rigid mechanical assembly which prevents any lateral deformation of the tubes with respect to each other. Heat treatment is carried out while the tubes are tightly bound in bundles, and each bundle is supported in the furnace at least at several locations along its length to prevent deformation. The bundles are preferably of hexagon shape in section but can be of other geometric shapes. This technique results in heat treated tubes which are perfectly straight.