The proposed invention is a catheter's system that can be used for concurrentfluid infusion and aspiration in humans, animals and biological material, ata wide range of flow rates, without any blockage problems. The proposed systemhas devices that control the infused liquid's pressure changes accordinglyto the aspirated liquid's pressure changes, in order to allow accurateand safe fluid exchange flow control and create changes of pressures at the catheter'stip that do not allow the catheter's blockage.
