The present invention relates to a multiple-bed downflow reactor comprising vertically spaced beds of solid contact material and a mixing device positioned in an inter bed space between adjacent beds. The mixing device comprises a loop of first nozzles distributed around a vertical axis and arranged for ejecting a fluid in a first ejection direction into said inter bed space, on the one hand, and a loop of second nozzles distributed around the vertical axis and arranged for ejecting a fluid in a second ejection direction into said inter bed space, on the other hand. The first ejection direction is directed inwardly with respect to the loop of first nozzles. The second ejection direction is directed outwardly with respect to the loop of second nozzles.