The invention concerns a device comprising a base; a circuit comprising a bag comprising two flexible films and conveying network connectors, and a press (9) comprising a first shell (16) disposed upright on a front face (5) of said base (2) and a second shell (17) mounted on said first shell (16), said first shell (16) and second shell (17) clamping said bag to form conduits; said bag comprising first through apertures on one side and said first shell (16) comprising hooking studs (106) on an upper part, which studs (106) pass through said first apertures.