The application of reducers in chemical pipeline systems mainly includes the following scenarios: Reducers are required when the flow rate of the fluid in the pipeline changes, such as increasing or decreasing, while the required flow velocity remains relatively constant. Reducers are also needed at pump inlets to prevent cavitation. Furthermore, reducers are required at connections with instruments such as flow meters and regulating valves to ensure proper fit.
Eccentric reducers are classified into top-flat and bottom-flat installations based on their installation direction. Top-flat installation (tangent point upwards) is generally used at pump inlets to facilitate venting; bottom-flat installation (tangent point downwards) is generally used for regulating valve installations to facilitate drainage. According to GB 50316-2000, the Code for Design of Industrial Metal Piping, horizontal eccentric reducers at centrifugal pump inlets generally use a top-flat arrangement. However, a bottom-flat arrangement can be used when the reducer is directly connected to an upward-bending elbow. The principle for selecting the installation method is to avoid the formation of air pockets or liquid accumulation in the pipeline, generally following the rule of "top inlet, bottom flat; bottom inlet, top flat."
