Abstract: A structure having at least one layer (3.1), for example three layers (3.1, 3.2, 3.3), of a number of juxtaposed sheet blocks, in which the sheets are shaped so as to define between themselves a series of vertical cells for water storage, and a series of horizontal cells in the height of the blocks for water drainage. The horizontal cells communicate with the vertical cells. The structure is light, inexpensive, easy to install without requiring heavy handling means, and is especially useful in underground water reservoirs.

Abstract: A bag (1) for filtering dust-laden gas in a bag filter that extends between a perforated plate (22) having holes (23) and support and positioning structure adjacent to a far end (17) of a filter box, is in the form of a tubular bag made from a U-shaped tube (1) having a flexible filtering wall that is permeable to the gas but that retains the dust transported thereby, the gas penetrating into the bag (1) and flowing in filtered form to an end opening (1f) of the wall that opens out in a hole (23) of the plate (22). The U-shaped tube of the bag (1) is mounted in the enclosure in such a manner as to present two tubular filtering lengths (1a, 1b) that are substantially parallel, with the base (1c) thereof being pinched to form a substantially gastight joint and being disposed towards the far end (17) of the enclosure. The invention is applicable to bag filters for cleaning dusty premises, and to filtering discharges made to the outside.

Abstract: A thermoformed sheet 1 for a plate-type gas-gas heat exchanger of the type comprising a case in which are stacked parallel plates spaced from each other by lateral spacing means, these plates having at their ends pointed regions provided with elements for alternately closing one of the two sides of the point, the case further comprising walls connected in a fluidtight manner to the pointed portions of the ends of the plates so as to form distinct inlet and outlet conduits for the gases which circulate in a countercurrent manner in the alternating spaces formed by the plates, this sheet being characterized in that it comprises a series of identical rows of elongated patterns 2a, 2b, 2c, 2d having edge portions folded on one side or the other of the sheet, each pattern comprising two parallel longitudinal edge portions 3a, 4a; 3b, 4b; 3c, 4c, 3d, 4d by which it is connected to the adjacent patterns so as to form a row and terminating in two pointed end portions 8a, 9a; 8b, 9b; 8c; 9c; 8d, 9d by which the patter