Suspended ceiling for cleanrooms

Suspended ceiling structure for cleanroom comprising a pressurized plenum, a lower face thereof defined by filter plates supported by a metallic structure having the shape of a horizontal grid, comprising extrusions (P1, P2, P3) crossing at a right angle, said extrusions (P1, P2, P3) having upper channels (15, 15') associated in such a manner that they form a continuous channel around each mesh of the grid and they form a support for a filter plate (13, 13'), said channels (15, 15') being filled with a material in which is received the lower end of a peripheral skin (14, 14') surrounding said filter plates (13, 13') to assure the sealing between the plenum and the volume beneath the ceiling structure, wherein each extrusion (P1, P2, P3) comprises at least one horizontal lateral groove (3) located in one of the vertical sides thereof, upon its full length and having the shape of a slide (2) and having at each end housings (4) opening to said lateral vertical sides to cooperate with fixation means (5, 6, 7) for affixing each of said extrusions to a perpendicular extrusion, said fixation means (5, 6, 7) also cooperating with a slide (2) of said perpendicular extrusion, which results in the continuous character of the upper channels (15, 15') of each mesh.