Retrofitted Input Channel With Varying Width For Grit Removal

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Solution Overview

Problem

Grit removal systems face inefficiencies due to varying wastewater flow rates, leading to insufficient flow velocity in input channels, causing grit to settle and accumulate instead of being properly removed, which affects the operational performance of the systems.

Innovation Solution

The input channel is retrofitted with a varying width design, incorporating stepped, flat, or curved side walls and the use of baffles to maintain a consistent flow velocity across different flow rates, ensuring grit is carried to the grit removal system effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the channel width is kept constant to simplify construction, then manufacturing ease is improved, but flow velocity becomes insufficient when flow rate varies, causing grit to settle

Engineering Contradiction:
Improvechannel construction simplicityVSAvoidflow velocity
Core Design Contradiction:
Ease of manufactureVSSpeed

Solution Approach 1:

The channel width is made variable rather than constant, allowing the cross-sectional area to change dynamically with flow rate. When flow rate increases, the channel widens to accommodate higher volume while maintaining appropriate velocity; when flow rate decreases, the channel narrows to prevent velocity drop and grit settlement.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The geometric parameter of channel width is changed from a fixed value to a variable value that responds to flow rate conditions. This parameter change enables the channel to adapt its hydraulic characteristics, ensuring optimal flow velocity across varying operational conditions without requiring complex active control systems.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the channel width is increased to accommodate higher flow rates, then adaptability to varying flow rates is improved, but flow velocity decreases causing grit to settle

Engineering Contradiction:
Improveflow rate accommodationVSAvoidflow velocity
Core Design Contradiction:
Adaptability or versatilityVSSpeed

Solution Approach 1:

The channel width is made variable rather than constant, allowing the cross-sectional area to change dynamically with flow rate. When flow rate increases, the channel widens to accommodate higher volume while maintaining appropriate velocity; when flow rate decreases, the channel narrows to prevent velocity drop and grit settlement.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Different sections of the channel have different width characteristics. The channel transitions from a narrower upstream section to a wider downstream section, with the transition point positioned to optimize flow velocity distribution. This local variation in geometry ensures that each section contributes appropriately to maintaining overall flow velocity across varying flow rates.

Inventive Principle:
Principle #3Local quality

3Speed

If concrete blocks or vertical steel plates are added to narrow the channel, then flow velocity is improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improveflow velocityVSAvoidchannel modification complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The channel is designed with pre-positioned formwork or molded sections that create the varying width profile during construction. Rather than adding modification elements like blocks or plates after construction, the velocity-enhancing geometry is built into the channel structure itself from the beginning, simplifying both construction and maintenance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The transition between different channel width sections is made smooth and curved rather than abrupt and angular. This curved transition promotes streamlined flow, reduces turbulence, and maintains velocity without requiring additional flow-directing elements or modifications, thereby avoiding increased device complexity.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

This solution ensures that the flow velocity of wastewater remains within a desired range, preventing grit from settling in the input channel and ensuring efficient operation of the grit removal system, even with varying flow rates over time.

Implementation Method 1

The input channel is retrofitted with a varying width design, incorporating stepped, flat, or curved side walls to maintain a consistent flow velocity across different flow rates

Methodology Applied
Scientific EffectFlow velocity maintenance through geometric design:

Implementation Method 2

flumes for injecting and extracting liquid (e.g., waste water) tangentially relative to a round chamber, thus creating a forced vortex in the chamber

Methodology Applied
Scientific EffectForced vortex:

Implementation Method 3

Flow velocity into the round chamber facilitates operation of the grit removal system by creating a circular flow stream which causes the grit to settle near the bottom center of the round chamber

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 4

adding a baffle along one side of the input channel to restrict the cross sectional opening allowing flow of water therethrough, the baffle selectively narrowing the width of the channel to less than W T to aid in increasing the velocity of the flow

Methodology Applied
Scientific EffectFlow restriction to increase velocity:

Data Source

PatentEP2582439B1Method of making an input channel, and a retrofitted input channel
Publication Date: 2019.03.06 SMITH & LOVELESS INC
  • EP2582439B1 patent drawingFigure 1a~1i
  • EP2582439B1 patent drawingFigure 2a~2b
  • EP2582439B1 patent drawingFigure 3a~3b

AI summary

An input channel (and method of making an input channel) for the flow of waste water into a grit removal unit. The input channel has a depth D extending from the bottom to the top of the channel. One side wall of the channel is configured to vary the channel width over the depth of the channel, whereby (a) the width at the bottom of the channel is WB, (b) the width at the top of the channel is WT, and (c) the width at channel depth "d" above the bottom of the channel is Wd, wherein (i) 0 = d = D, (ii) WB T, and (iii) Wd is greater than or equal to the channel widths at substantially every channel depth less than "d". The channel profile may be integral to the channel, or defined by a separately added component, and selectively be stepped, tapered and/or curved.