Abstract: Improved methods and apparatus for providing a fluid flow and mounting system comprised a mounting nipple, a coupling for threaded engagement with a valve assembly, and a rigid flow line having preselected dimensions. The system of the present invention is particularly adapted for supporting a sampling pump from a pipe line, with the sampling pump including a manifold block having a pair of fluid ports for passing fluid in a hot-loop between the flow line and a sampling pump, and with the valve assembly being mounted to the flow line and including a pair of through passageways. The mounting nipple has a stop surface at each end thereof for engaging the manifold block and valve assembly, respectively, to fix the axial position of the manifold block with respect to the valve assembly. The coupling is rotatable about the mounting nipple for threaded engagement with mating threads on the valve body.