Abstract: The present invention relates to external combustion engines and more precisely to motors using the Stirling cycle designed to directly convert thermal energy into electrical energy.In accordance with the invention, this transformation is carried out inside a machine which is completely sealed, without a mechanical connection with the outside, in which the power piston drives the moveable part of an electrical generator. In accordance with one preferred embodiment, this electrical generator is a linear alternator. In accordance with a further original feature of the invention, control of the coupling between the displacing piston and the power piston is carried out by using electronic regulation.

Abstract: A solar collector is designed for converting solar radiation into heat and transferring the heat thus collected, by means of a chamber formed of a window exposed to the sun and allowing passage of solar radiation, and of a bottom or opposite end-face. This radiation is absorbed by adequate means fitted inside this chamber, and the heat it entails is carried off outside the latter. Both the window and the bottom which form the chamber, are made of glass elements hermetically sealed to one another along their periphery by low-melt glass welding.

Abstract: A solar energy collector having concave mirrors shaped as troughs of parabolic cross-section with a longitudinal pivotal axis enabling them to be aimed at the sun and having, at intervals, connecting members for maintaining at the mirror focus a heat receiving tube of small diameter by comparison with the mirror aperture. A dusttight and moisturetight transparent chamber isolates both the receiving tube and the surface of the mirror from the surrounding atmosphere.

Abstract: The concrete vault roof of a liquid metal cooled fast reactor is provided with a heat-insulating lining plate and has a central passage for rotating shield plugs surrounded by passages for heat exchangers and pumps. An annular plate of relatively small thickness is placed horizontally beneath the vault roof and its external edge is joined to the lining plate by means of shaped members having a long radius of curvature so as to form closed spaces for trapping an inert gas. The free edges formed by the openings in the annular plate are joined to the lining plate by means of a sealing shell.