Ansi Hi 9.8 — Rotodynamic Pumps For Pump Intake Design

The ANSI/HI 9.8-2024 standard, titled Rotodynamic Pumps for Pump Intake Design, is a critical industry benchmark for designing or modifying pumping facilities to ensure uniform, swirl-free, and air-free flow. Developed by the Hydraulic Institute (HI), it bridges fluid mechanics theory with practical geometry to maximize pump efficiency and lifespan. Core Design Objectives

1. Bellmouth Inlets: Bellmouth inlets should be designed with a gradual expansion to minimize turbulence and ensure a smooth flow into the pump.
2. Elbow Inlets: Elbow inlets should be designed with a large radius to minimize turbulence and ensure a smooth flow into the pump.
3. Intake Screens: Intake screens should be designed to minimize head loss and prevent debris from entering the pump.

Some of the key provisions of ANSI HI 9.8 include: ansi hi 9.8 rotodynamic pumps for pump intake design

A. Bell Diameter (Db) vs. Pipe Diameter (Dp)

The pump bell (the flared inlet) is larger than the suction pipe. HI 9.8 defines Db as the critical dimension. All distances are ratios of Db. The ANSI/HI 9

6. Vortex Prevention

• HI 9.8 defines vortex types (1 to 6) from harmless surface swirl to damaging air-core vortices.
• Type 5 & 6 vortices (air-entraining) are unacceptable – require baffles, anti-vortex plates, or increased submergence.