A fluid processing device (10) for processing fluid, wherein the fluid processing device (10) comprises a first fluid drive unit (20) configured for driving a first fluid along a first flow path (85), a second fluid drive unit (20′) configured for driving a second fluid along a second flow path (86), and a fluidic switch (90) fluidically coupled to the first flow path (85) and to the second flow path (86) and configured for being switchable for transferring first fluid from the first flow path (85) into the second flow path (86) without interruption of fluid flow along at least one of the first flow path (85) and the second flow path (86).