Abstract: A method of cleaning a light-transmissive and/or light reflective surface in contact with a fluid flow comprising particles extracted or generated in an oil extraction installation is described. The method comprises providing a source of flushing fluid comprising ozone, providing means for flushing the surface with the flushing fluid, and operating flushing means such that the surface is flushed with the flushing fluid. Apparatus for optically monitoring characteristics of such a fluid flow, the apparatus being adapted to take advantage of the aforementioned method, is also described.

Abstract: A resilient sports floor comprising a top layer, which is designed to be a coherent sheet consisting of boards. In each board recesses are provided in the shape of mutually parallel grooves along the entire length of the board, in which grooves strips of a springy resilient material, e.g. a natural or synthetic rubber material or a porous, springy plastic material, are inserted. The thickness of strips is larger than the depth of grooves, so that the strips project below the underside of layer with their lower portion. The floor is provided with the free surface of strips directly against a rigid sub-floor. In case of extremely high loads strips will be pressed into grooves, so that the strips are relieved due to the fact that the floor is in direct contact with the sub-floor with its underside.