Abstract: The cover for a swimming pool has a side facing the water and an opposite side facing away. The cover defines an elongated cavity having a single flooding opening facing the water and arranged at one end of the cavity for flooding the pool, the cavity having a venting port at an end thereof opposite to the one end having the flooding opening. A vent valve in the port can close the port and a connection to a source of gas under pressure leads to the cavity for supplying the gas under pressure to the cavity to displace the water in the cavity. The mass of the cover exceeds that of the displaced water in case the cavity or cavities are flooded.

Abstract: Continuous casting plant rollers or rolls of small diameter are provided great longitudinal extension, which longitudinal extension exceeds the width of the continuously cast strand. The rollers or rolls have annular recesses distributed over their longitudinal extension, thus forming substantially cylindrical bearing pins to be received in bearings, preferably slide bearings, whose bearing height, measured from the bearing center toward the strand skin, is smaller than the radius of the rollers or rolls. The rollers or rolls may advantageously be composed of a plurality of individual roller or roll bodies held together by at least one bracing anchor. Preferably, the rollers or rolls are provided with internal cooling.