60 serves as an insulation for preventing high temperatures of the cylindrical wall 11 of the oxygen generator in course of the exothermic reaction of the solid oxygen source 50 fig3 and 4 show a second embodiment of the invention in the second embodiment a hollow tube 140 embedded in a solid oxygen source 150 is provided in a similar arrangement as in the first embodiment of the fig1 and 2 still further said hollow tube 140 is positioned within a housing not shown by way of ring shaped elements 114 115 the outer diameter of which corresponding to the inner surface of a cylindrical wall 111 of the housing in a similar design as shown in fig1 and 2 a starter unit 120 is arranged at a front end cover 112 and is in contact to the solid oxygen source 150 via a channel 121 in contrast to the first embodiment of fig1 and 2 the second embodiment shown in fig3 and 4 has an outlet conduct 130 which is arranged at the front end cover 112 i e at the same end like the starter unit 120 the back end cover 113 of the second embodiment is a closed cover with a slightly convex shape it defines a flow chamber 116 which is in fluid communication with a central opening 115 a in the ring shaped element 115 and a plurality of eccentric openings 115 b in said ring shaped element 115 the openings 115 a and b are oriented in an axial direction parallel to the longitudinal axial 101 of the oxygen generator the central opening 115 a is in fluid communication with the interior of.