Abstract: The invention relates to a blood-treatment device including hollow fibers which are suitable for conveying a fluid and are in a plurality of superposed layers arranged in directions which are offset from layer to layer so as to create a uniform flow of blood from an inlet chamber adjacent one end layer of the plurality of superposed layers to an outlet chamber adjacent the other end layer, the blood passing through the layers in a direction substantially perpendicular thereto and bathing the external surfaces of the hollow fibers.

Abstract: The technical field dealt with is that of fluid conveyance, and the invention relates to a device for selectively sampling fluid from two sections of a line which ensures great operating practicality and minimal dimensions. The solution consists of a device comprising a selecting element with a cavity associable with a syringe and comprising an appendix suitable for rotating in a seat of a fixed element to which converge three conduits, the two end conduits being connectable with the two parts of the line and the central conduit being connectable with a drain, said selecting element having two passages, each of which is suitable for establishing a communication between one of the end conduits and the central conduit, and a third intermediate passage suitable for establishing a communication selectively between the two end conduits and said cavity.