Underdrain Filter Block Grout Chamber Design for Uplift Resistance

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Solution Overview

Problem

Conventional underdrain filter blocks are susceptible to uplift failure due to internal pressure caused by headloss, leading to deformation and detachment from the filter floor.

Innovation Solution

The underdrain filter block design incorporates a grout chamber and openings in the bottom and side walls that allow grout to fill and secure the block in place, providing structural support and preventing uplift failure by stiffening the bottom wall against internal pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional underdrain filter blocks are used, then the structure is simple, but the block is susceptible to uplift failure due to internal pressure

Engineering Contradiction:
Improveblock structureVSAvoidresistance to uplift failure
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The block is segmented into multiple grout chambers separated by internal walls, with each chamber containing ribs that create multiple grout pockets. This segmentation allows grout to be distributed throughout the block structure, providing multiple anchoring points that collectively resist uplift forces while maintaining overall structural integrity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a simple flat bottom wall design to a three-dimensional grout chamber system with vertical ribs and internal walls. This dimensional change creates multiple levels of grout engagement (top surface, bottom surface, and internal chamber walls), significantly increasing the surface area for grout adhesion and uplift resistance

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Strength

If the bottom wall is made thicker to resist internal pressure, then uplift resistance improves, but manufacturing complexity and material usage increase

Engineering Contradiction:
Improvebottom wall strengthVSAvoidblock construction
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

Instead of using a single thick bottom wall, the structure is segmented into multiple thinner walls forming grout chambers and ribs. These segmented walls work together with grout infill to achieve the required strength, distributing the load across multiple elements rather than concentrating it in one thick component

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention creates a composite structure combining the block material (plastic or concrete) with grout infill. The grout acts as a reinforcing material that fills the chambers and bonds to the ribs and walls, creating a composite system where the combination of materials provides superior strength-to-weight ratio compared to a solid thick wall

Inventive Principle:
Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design effectively secures the filter block to the filter floor, preventing uplift failure and maintaining stability under internal pressure conditions.

Implementation Method 1

The plurality of grout chambers are positioned below the bottom wall. Each one of the plurality of wall segments defines a plurality of openings. The underdrain filter block may further include a primary chamber and at least one second chamber defined by an arched wall.

Methodology Applied
Scientific EffectGrouting: Adhesive

Data Source

PatentEP3868454B1Apparatus for securing underdrain filter block
Publication Date: 2026.04.01 XYLEM WATER SOLUTIONS ZELIENOPLE LLC
  • EP3868454B1 patent drawingFigure 1~2
  • EP3868454B1 patent drawingFigure 3~4
  • EP3868454B1 patent drawingFigure 5

AI summary

An underdrain filter block for use in draining and backwashing a filtering media in a filter bed includes a top wall, a pair of side walls extending from the top wall, a bottom wall extending between the pair of side walls, and a transverse wall extending from one of the pair of side walls to the other of the pair of side walls. The top wall, the pair of side walls, and the bottom wall define an upper portion and a lower portion. The lower portion includes a grout chamber positioned between the bottom wall and the transverse wall and at least one of the bottom wall and said side walls contains an opening.