This invention pertains to a segmented insert installed within the horizontal conduit of a non-mechanical means (such as an L-valve) for controlling the external flow of particulate material recycled to a fluidized bed combustor. The segmented insert is insulated to protect the horizontal conduit and the individual segments are joined together by a combination of a collar and hinge means. This method of coupling retains the co-axial alignment of the individual segments for leak-free operations while also enabling them to move or pivot independent of each other while still being connected together. Such independent movement is necessary for stress release purposes during high temperature operation.