Underdrain Lateral with Dual Outer Chambers for Uniform Backwash Distribution
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Solution Overview
Problem
Existing underdrain systems in water and wastewater filter systems often suffer from uneven distribution of washing fluids, leading to incomplete cleaning of filter media, shorter filtration cycles, and increased maintenance needs due to mal-distribution and uplift forces that can cause underdrain laterals to separate from the filter floor.
Innovation Solution
The design includes a novel underdrain lateral with dual outer chambers and inner chambers that ensure uniform distribution of washing fluids through mal-distribution members and a support assembly to prevent relative movement between inner and outer liners, along with a fluid pressure tap member to monitor fluid pressure and prevent mal-distribution, effectively anchoring the underdrain laterals to the filter floor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional lateral underdrain system is used, then the structure is simple and easy to manufacture, but the washing fluid distribution becomes uneven leading to incomplete filter media cleaning
Solution Approach 1:
The underdrain lateral is divided into multiple separate chambers (first outer chamber, second outer chamber, inner chamber) that are arranged in sequence. Each chamber has specific openings and mal-distribution members that work together to segment and control fluid flow paths, ensuring uniform distribution across the filter media width while maintaining manageable structural complexity
Solution Approach 2:
Different chambers and regions of the underdrain lateral are designed with different properties - the outer chambers have openings for fluid entry, the inner chamber has mal-distribution members for flow control, and specific regions have elevated portions for anchoring. This local differentiation optimizes fluid distribution uniformity without requiring complete redesign of the entire structure
2Reliability
If the underdrain laterals are not anchored to the filter floor, then the installation is simpler, but uplift forces from water and air flow cause the laterals to separate from the filter floor making the filter inoperable
Solution Approach 1:
The underdrain lateral includes pre-formed elevated portions with openings designed to receive anchors before the filter media is installed. The anchors are inserted through these pre-positioned openings and secured to the filter floor, creating a reliable anchoring system that prevents uplift separation while maintaining straightforward installation procedures
Solution Approach 2:
An anchor assembly acts as an intermediary element between the underdrain lateral and the filter floor. The anchor receives the elevated portion of the underdrain lateral and secures it to the filter floor, transferring uplift forces from the water and air flow to the stable filter floor structure without requiring complex direct attachment methods
3Reliability
If washing cycles are performed frequently to maintain filter performance, then the filtration quality is maintained, but the operational time in filtration cycle is reduced
Solution Approach 1:
The underdrain lateral incorporates mal-distribution members and specifically designed chamber configurations that automatically ensure uniform washing fluid distribution across the filter media during backwash cycles. This self-correcting design thoroughly cleans the filter media without requiring extended washing times, allowing the system to maintain high filtration quality while maximizing productive filtration cycle duration
Data Source
AI summary
An apparatus for use in a filter system for filtering water or wastewater. The apparatus preferably includes at least one underdrain lateral having at least an inner chamber, a first outer chamber and a second outer chamber. The first outer chamber and the second outer chamber are preferably in fluid communication with the inner chamber. The inner chamber, the first outer chamber and the second outer chamber are preferably formed by an inner liner and an outer liner. The outer liner is a separate piece from the inner liner and surrounds the inner liner. The inner chamber is preferably configured to simultaneously receive a liquid and a gas during a washing procedure including simultaneous use of a liquid and gas to clean a filter bed to create a liquid and gas interface in the inner chamber.