Abstract: This paper introduces the design principles of pump inlet pipe, takes the inlet pipes of several hot-oil pumps in the CDU/VDU and light hydrocarbon complex of a refinery as an example, discusses the optimization schemes of piping layout based on the CASERII stress analysis results, and focuses on the solutions to the problems emerged during the flexibility design of pump inlet pipe, i.e. how to meet the requirements of pump nozzle stress by optimizing the piping layout, changing the pipe-wall thickness and taking some other measures.

Key words: hot-oil pump, inlet pipe, nozzle stress