Tube exchange device for holding and replacing an exchangeable pouring nozzle for casting molten metal out of a vessel, said tube exchange device comprising a frame with a casting opening, said frame being suitable for being fixed to the lower side of a metal casting vessel and comprising a first, upper portion and a second, lower portion, joining at a middle section plane defining the plane where an inner nozzle and an exchangeable pouring nozzle form a sliding contact, the upper side portion of the frame comprising: (a) means for receiving and clamping (50a, 50b, 50c) in place at its pouring position a bearing surface of an inner nozzle against a support portion of the upper side portion of the frame, such that the through bore of the inner nozzle is in fluid communication with the casting opening, and the lower side portion of the frame comprising, (b) a passage extending along a first axis of first direction between an inlet opening and an outlet opening suitable for receiving and moving an exchangeable pouring nozzle from said inlet to said outlet, passing by a casting position in registry with the casting opening of the frame, (c) means for displacing and means for guiding said exchangeable pouring nozzle from a standby position to a casting position in registry with the casting opening of the frame, and optionally for guiding it to the outlet, said guiding means running substantially parallel to the first direction, (d) pressing means aligned with the guiding means and extending substantially parallel to the first direction at the level of the pouring nozzle casting position for pressing up said exchangeable pouring nozzle at its casting position in the direction of the upper portion of the frame, characterised in that the clamping means comprise three clamping elements (50a, 50b, 50c), wherein the respective centroids of the orthogonal projections onto the middle section plane of the clamping elements in their clamped position form the vertices of a triangle and in that the clamping means (50a, 50b, 50c) are arranged transverse to said first direction. (a) means for receiving and clamping (50a, 50b, 50c) in place at its pouring position a bearing surface of an inner nozzle against a support portion of the upper side portion of the frame, such that the through bore of the inner nozzle is in fluid communication with the casting opening, and the lower side portion of the frame comprising, (b) a passage extending along a first axis of first direction between an inlet opening and an outlet opening suitable for receiving and moving an exchangeable pouring nozzle from said inlet to said outlet, passing by a casting position in registry with the casting opening of the frame, (c) means for displacing and means for guiding said exchangeable pouring nozzle from a standby position to a casting position in registry with the casting opening of the frame, and optionally for guiding it to the outlet, said guiding means running substantially parallel to the first direction, (d) pressing means aligned with the guiding means and extending substantially parallel to the first direction at the level of the pouring nozzle casting position for pressing up said exchangeable pouring nozzle at its casting position in the direction of the upper portion of the frame,