Abstract: A metallurgical vessel such as a tundish fitted with a slide gate at its underside for discharging its contents has the slide gate controlled by a drive that can be removed to another vessel when required. The drive comprises a hydraulic cylinder with a drive rod projecting from it and carrying a coupling releasably engageable with the slide gate. The cylinder and drive rod are clamped non-rotatably in use but when attaching or removing the drive they can be rotated about a common longitudinal axis to alternative angular positions in which the slide gate is coupled or uncoupled thereto. Changeover of the drive can be made quickly thereby. A double-ended drive constructed in this manner can be used with vessels having two controllable outflow devices and provides for an equally quick changeover.