Abstract: The invention relates to an apparatus comprising a reactor, elongated along one axis, preferably of square or rectangular cross section. The reactor has, at one extremity, at least one supply line for at least one reactant and at least one evacuation outlet at the other extremity for removal of produced effluents. In a first zone (near the first extremity of the reactor), a plurality of heat exchangers, substantially parallel to each other, are disposed in substantially parallel layers perpendicular to the reactor axis, thereby defining spaces or passages for circulation of reactant(s) and/or effluents between the heat exchangers and/or layers formed by the heat exchanger. The heat exchangers are adapted to exchange heat in the passages through successive transverse sections, which are independent and substantially perpendicular to the reactor axis.

Abstract: A burner system comprising a central hearth tube defining a combustion chamber for a mixture of gas and air and made from thermomechanical ceramic, a tubular element comprising at its end located towards the gas outlet a radial restriction forming an axial and radial positioning stop for the hearth tube whereas the assembly of the latter to the other component parts of the burner is effected by a spring adapted to produce an axial pressure force under the impact of which the hearth tube is bearing upon said stop through a radial shoulder provided in its reduced portion, the burner providing a high velocity of outflow of the burnt gases.

Abstract: An inner tube for a radiant tube for recirculating burnt gases supplied by a burner, consisting of a plurality of axially aligned assembled tube sections arranged end to end whereas the assembling means consist each one of a sleeve coaxially surrounding the ends of said sections to be interconnected and the radially inner surface of which comprises in the middle of its length an annular collar projecting radially inwards and fitting between both tube sections to be connected together, the inner surface portions which are located on either side of the collar widening gradually towards the sleeve ends.

Abstract: A method and device for the numerical coding of an image, more particularly a television image, made up of pixels (elementary points) which are regularly distributed in the plane of the image, and to which one or more radiometric qualities denoted as components C.sub.i are allotted. In the image, windows (f) are determined which have a predetermined geometrical shape and comprise a certain number of pixels (p); for each window regroupings are carried out into classes (R1,R2 . . . ) of radiometries (spectral or spatial) of the ends of the vectors representing the pixels or combinations of pixels of the image in space of N dimensions, in accordance with a criterion of proximity; for each class (R1,R2 . . . ) from the individual values of the pixels forming the class, N typical radiometries are defined which will be stored or transmitted to be used in the reconstruction of the image; to define each pixel, a characteristic code of the class (R1,R2 . . .

Abstract: An image represented by samples N.sub.o,o, N.sub.2,o, . . . , N.sub.2p,o, . . . , N.sub.o,2, . . . , N.sub.o,2q, . . . , N.sub.2p,2q, . . . , distributed over a two-dimensional pattern and each represented by a quantified signal, generally at two levels, is restored. From samples such as N.sub.2p,2q, are reconstituted samples such as m.sub.2p,2q, m.sub.2p+1,2q, m.sub.2p,2q+1, m.sub.2p+1,2q+1, quadruple in number. The values of the four samples are generated according to the expansion relationships: ##EQU1## The samples N are typically obtained by a compression process.