Apparatus for concentrating solar radiation with inflatable concentrator cushion

A device for the concentration of solar radiation in an absorber, comprising an inflatable concentrator cushion, which comprises a cover film element comprising a light-permeable entry window for coupling in solar radiation and a reflector film, which sub-divides the concentrator cushion into at least two hollow spaces, for the concentration of solar radiation in an absorber, comprising a pivoting apparatus, by which the concentrator cushion can be pivoted, in particular about its longitudinal axis, and comprising a retaining apparatus secured to the pivoting apparatus, for retaining the concentrator cushion, which retaining apparatus comprises an upper longitudinal member extending in the longitudinal direction of the concentrator cushion, for suspending the absorber, wherein the upper longitudinal member is arranged on a substantially air-tight closed upper passage opening of the concentrator cushion, wherein the upper longitudinal member comprises at least two longitudinal bars, which extend in the longitudinal direction of the concentrator cushion and which are in each case connected to a longitudinal edge of the cover film element, which longitudinal edge delimits the upper passage opening, wherein a sealing film strip is provided between the longitudinal bars, which sealing film strip bridges the upper passage opening of the concentrator cushion.