A device for filtration with a set of at least one filter cassette (2; 102; 202) comprising: - a manifold (3; 103; 203) providing fluid connection and mechanical connection comprising at least one flow inlet for a fluid to treat, at least one flow outlet for a treated fluid and a network for conveying said fluid to treat and said treated fluid, said manifold (3; 103; 203) having a bearing surface (22; 222) for a said filter cassette (2; 102; 202), through which bearing surface (22; 222) emerge cassette feed ports and cassette return ports communicating with said conveying network, which cassette feed ports and cassette return ports are configured to communicate with conduits (11, 12, 13) formed in a said filter cassette (2; 102; 202) bearing against said bearing surface (22; 222); - a clamping plate (4, 34; 204, 234) distinct to said manifold (3; 103; 203); and - means for driving and guiding said clamping plate (4, 34; 204, 234) parallel to and facing said bearing surface (22; 222), that are formed by at least one rod (6, 36; 106; 206, 266) which extends between said manifold (3; 103; 203) and said clamping plate (4, 34; 204, 234) and by at least one actuator (10; 210), which is provided with a body (52; 252) and a member (53; 253) moveable relative to said body (52; 252), which moveable member (53; 253) has an extended position and a retracted position in which said moveable member (53; 253) has been moved through a predetermined travel relative to its extended position, by virtue of which the clamping plate (4, 34; 204, 234) has a starting position in which said plate (4, 34; 204, 234) is away from said set of at least one filter cassette (2; 102; 202) and a clamped position in which said plate (4, 34; 204, 234) is approached and compresses said set of at least one filter cassette (2; 102; 202) against said manifold (3; 103; 203); wherein that said body (52; 252) is carried by said manifold (3; 103; 203); said moveable member (53; 253) carries said rod (6, 36; 106; 206, 266); and said actuator (10; 210), said rod (6, 36; 106; 206, 266) and said clamping plate (4, 34; 204, 234) are configured such that said actuator (10; 210) drives said clamping plate (4, 34; 204, 234) via said rod (6, 36; 106; 206, 266) to its clamped position in which said moveable member (53; 253) is in an intermediate retracted position in which said moveable member (53; 253) has moved through a shorter travel than said predetermined travel relative to its extended position; the rod (6, 36; 106; 206, 266) being fixed to the moveable member (53; 253) so that said rod is also moveable and the clamping plate (4, 34; 204, 234) being mounted on and borne by said rod such that on moving of the moveable member of the actuator, the rod and the clamping plate move all together; characterized in that said device comprises at least one third rod (8, 38; 108) for supporting said clamping plate (4, 34; 204, 234) which is carried by said manifold (3; 103; 203) and in that the device comprises means (9, 39) for mounting said clamping plate (4, 34) on said supporting third rod (8, 38; 108) comprising a slide and a hinge, by virtue of which said clamping plate (4, 34; 204, 234) is slidingly moveable along the supporting third rod (8, 38; 108) and has a working configuration in which it is raised parallel to and facing said bearing surface (22; 222) and a stored configuration in which it is folded down and clear of said rod (6, 36; 106; 206, 266). - a manifold (3; 103; 203) providing fluid connection and mechanical connection comprising at least one flow inlet for a fluid to treat, at least one flow outlet for a treated fluid and a network for conveying said fluid to treat and said treated fluid, said manifold (3; 103; 203) having a bearing surface (22; 222) for a said filter cassette (2; 102; 202), through which bearing surface (22; 222) emerge cassette feed ports and cassette return ports communicating with said conveying network, which cassette feed ports and cassette return ports are configured to communicate with conduits (11, 12, 13) formed in a said filter cassette (2; 102; 202) bearing against said bearing surface (22; 222); - a clamping plate (4, 34; 204, 234) distinct to said manifold (3; 103; 203); and - means for driving and guiding said clamping plate (4, 34; 204, 234) parallel to and facing said bearing surface (22; 222), that are formed by at least one rod (6, 36; 106; 206, 266) which extends between said manifold (3; 103; 203) and said clamping plate (4, 34; 204, 234) and by at least one actuator (10; 210), which is provided with a body (52; 252) and a member (53; 253) moveable relative to said body (52; 252), which moveable member (53; 253) has an extended position and a retracted position in which said moveable member (53; 253) has been moved through a predetermined travel relative to its extended position, by virtue of which the clamping plate (4, 34; 204, 234) has a starting position in which said plate (4, 34; 204, 234) is away from said set of at least one filter cassette (2; 102; 202) and a clamped position in which said plate (4, 34; 204, 234) is approached and compresses said set of at least one filter cassette (2; 102; 202) against said manifold (3; 103; 203);