Apparatus for cleaning the inner side of a tank

An apparatus for cleaning the inner side of a tank, the apparatus comprising:

• a frame which is mounted or mountable to a tank,
• a nozzle support which is rotatably mounted to the frame and drivable with respect to the frame about a first axis of rotation,
• a nozzle which is rotatably mounted to the nozzle support and drivable with respect to the nozzle support about a second axis of rotation extending transversely to the first axis of rotation, wherein the nozzle has a spraying direction facing away from the second axis, and
• a controller configured to drive the nozzle support and the nozzle, wherein the controller is configured such that, under operating conditions, the nozzle is rotated about the second axis alternatingly (i) from a cleaning start position to a cleaning stop position by a predefined cleaning angle and (ii) from the cleaning stop position to the cleaning start position, which cleaning angle is smaller than one revolution, and an angular velocity of the nozzle with respect to the nozzle support during the movement of the nozzle from the cleaning start position to the cleaning stop position within the cleaning angle is (i) smaller than an angular velocity of the nozzle support with respect to the frame and (ii) smaller than an angular velocity of the nozzle with respect to the nozzle support during the movement of the nozzle from the cleaning stop position to the cleaning start position.