Manifolds, Rotating and Stationary

Pipe manifolds with unsteady flow are frequent occurrences in civil engineering design. Rotating manifolds are used on trickling filters with rotary distributors, and stationary manifolds are used in filter underdrains, tank and reservoir blending pipes, and sewer outfalls plus other applications. The hydraulic design of manifolds is developed in a straightforward theoretical manner; then a practical means of handling manifold design is suggested. Manifolds behave in an unorthodox manner and unless understood, they will not function as expected. A pertinent characteristic of I manifolds is that the hydraulic gradient can actually go up in the direction of flow. This is a fact that can be used to good advantage by the designer. A suggested application for optimum distribution of wash water through a sand filter underdrain is shown.