The invention concerns a propagator with a skeletal structure consisting of floor (5), roof (3), side (1) and door elements (1′) which can each be separately and variably joined together and each have a light- and airtight covering (7) and guides (9) for stabilization and also connecting elements (11, 17). The covering (7) consists of several layers and has a highly reflective inner layer.The stabilizing elements are made of round steel tubes. The connectors are flaps (11) which are connected to one another with hook-and-loop fastenings (13). A further connector element is a three-arm connector (17) for connecting side elements (1, 1′) to one another.The invention also involves a flange for connecting an interior compartment to an exterior framework, with a threaded connector (23) which can be guided precisely through an opening (21) in the border between the interior and the outside, and a threaded ring (25) which works together with the thread on the connector (23) to form the flange.
