Process flow diagram
（重定向自Process Diagram）
![Some typical elements from process flow diagrams, as provided by the open source program, Dia. Click for image legend.](/Images/godic/202502/04/Pfd-symbols0514.png")
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A process flow diagram (PFD) is a diagram commonly used in chemical and process engineering to indicate the general flow of plant processes and equipment. The PFD displays the relationship between major equipment of a plant facility and does not show minor details such as piping details and designations. Another commonly used term for a PFD is a flowsheet.