We originally introduce a device to achieve monitored flows of Langmuir monolayers on predesigned wet circuits imprinted on a solid support. The hydrophilic track is first engraved in contact with a hydrophobically coated metallic plate that is fitted into a three-compartment Langmuir trough. Two different designs are tested to confirm flow stability and control. In particular and as a first utility, we measure the diffusion coefficient of a fluorescent probe using Y-junction geometry.