Device to generate a flow of cold gas

In a device to generate a flow of cold gas by means of the heat exchange of a cryogenic medium with a heat transfer medium, the improvement being in a first heat exchanger having a heat transfer medium inlet and a heat transfer medium outlet, said first heat exchanger having a liquefied cryogenic medium inlet and an evaporated cryogenic medium outlet, a second heat exchanger having an evaporated gaseous cryogenic medium inlet, a connection line communicating with said evaporated gaseous cryogenic medium outlet of said first heat exchanger and said evaporated gaseous cryogenic medium inlet of said second heat exchanger for supplying the evaporated gaseous cryogenic medium from said first heat exchanger to said second heat exchanger, said second heat exchanger having a liquefied cryogenic medium inlet for flowing liquefied cryogenic medium through said second heat exchanger to re-cool the evaporated gaseous cryogenic medium and to evaporate the liquefied cryogenic medium, a mixing site, and connection lines communicating with said mixing site to supply the re-cooled cryogenic medium and the evaporated liquefied cryogenic medium from said second heat exchanger to said mixing site for mixing said mediums at said mixing site.