Sedimentation Hood With Fill Structure Prevents Bridging
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Solution Overview
Problem
Existing solids removal methods in sedimentation tanks face challenges with lightweight flocculants, which are susceptible to resuspension due to turbulence, and require continuous operation to prevent bridging, leading to increased hydraulic load and reduced system capacity.
Innovation Solution
The implementation of an elongated hood with converging sidewalls and a fill structure within the sedimentation tank, featuring inlet and outlet openings, and upright outlet pipes that create a restricted flow path to maintain solids in suspension and prevent bridging, allowing for efficient removal of solids without disturbing settled materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If physical scraping devices are used to remove solids from the bottom of the sedimentation tank, then solids removal efficiency is improved, but lightweight flocculants are resuspended into the clarified liquid
Solution Approach 1:
The invention extracts the solids removal function from mechanical scraping devices and relocates it to the bottom outlet region where solids naturally concentrate. By positioning the outlet at the lowest point and using gravitational settling, solids are removed passively without physical contact that would cause resuspension of lightweight materials.
Solution Approach 2:
The invention replaces the mechanical scraping system with a gravitational settling system. Instead of using motorized scrapers or plows to physically move solids, the system relies on gravity to cause solids to settle to the bottom outlet where they are continuously withdrawn, eliminating mechanical disturbance that resuspends flocculants.
2Productivity
If continuous solids removal is implemented in flow-through sedimentation tanks, then solids accumulation is prevented, but turbulence is generated that resuspends settled solids
Solution Approach 1:
The invention enables the sedimentation tank to self-remove solids through gravitational settling and natural concentration at the bottom outlet. The continuous withdrawal of solids occurs passively without external mechanical intervention, allowing the bulk of the tank to remain quiescent while solids are automatically removed at the bottom.
Solution Approach 2:
The invention creates a localized solids removal zone at the bottom outlet where continuous withdrawal occurs, while the rest of the tank maintains quiescent conditions. The converging sidewalls and fill structure concentrate solids flow locally at the outlet, separating the solids removal function from the bulk sedimentation zone.
3Productivity
If hopper structures with steep slopes are used to collect solids, then solids collection efficiency is improved, but the hopper extends upward into the sedimentation tank creating turbulence
Solution Approach 1:
The invention resolves the spatial conflict by extending the hopper structure horizontally along the bottom of the tank rather than vertically upward. The converging sidewalls create a horizontal flow path that collects solids along the tank length, keeping the collection structure confined to the bottom zone and preventing intrusion into the vertical sedimentation space.
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 enables effective removal of solids of varying densities, including lightweight flocculants, while minimizing resuspension and hydraulic disturbances, maintaining system capacity by ensuring solids are kept in suspension and preventing bridging, thus optimizing the solids removal process.
Implementation Method 1
causing at least a part of the solids to first descend within the tank and pass through a restricted opening
Implementation Method 2
The waste water-solids suspension moves at a velocity of at least 1.5 feet per second (fps) through the restricted opening, and then moves at a velocity of at least 1 fps during the upward movement thereof along the restricted flow path
Data Source
AI summary
Solids removal assemblies (14) adapted for use in flow-through or batch-type sedimentation tanks (12) are provided which increase the efficiency of solids removal and eliminate physical scraping devices common with such sedimentation tanks. The preferred removal assemblies (14) include an elongated hood (34) disposed over a cooperating and complementally configured fill structure (26,28), which fills the majority of the internal volume of the hood (34). The hood (34) includes converging sidewalls (44, 46) having lower most inlet openings (54) and spaced, tubular outlets (56) adjacent the apex thereof. Outlet pipes (64) are operably coupled with each of the hood outlets (56) for suction withdrawal of waste water-solids suspensions which are then conveyed for downstream processing. The hood (34) and fill structure (26, 28) cooperatively define restricted flow paths for the waste water-solids suspensions, and assist in the creation of relatively high velocity movement of the suspensions to prevent bridging or clogging by collective solids adjacent the bottom of the tanks (12).