Nested Tray Separator for Grit Resuspension and Blockage Control
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Solution Overview
Problem
Existing separators for removing grit from wastewater are prone to resuspension of settled solids, leading to reduced efficiency and potential blockages due to insufficient spacing between tray units.
Innovation Solution
A separator design with nested tray units featuring a specific offset ratio and concavity ratio in the settling portion, along with controlled inlet positioning and minimum gaps, to minimize resuspension and blockages while enhancing collection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the trays are spaced closely together to increase separation capacity, then productivity is improved, but the risk of blockages increases due to insufficient spacing
Solution Approach 1:
The patent employs nested tray units where one tray is positioned inside another, creating a compact stacked arrangement. This nesting configuration allows multiple trays to be closely spaced vertically without requiring excessive horizontal clearance, thereby increasing separation capacity while maintaining adequate spacing to prevent blockages between adjacent trays
Solution Approach 2:
The invention transitions from a horizontal arrangement of trays to a vertical stacked configuration. By arranging trays in the vertical dimension rather than horizontally, the system achieves higher separation capacity within the same footprint while maintaining sufficient spacing between trays to avoid blockages
2Manufacturing precision
If the inlet opening is positioned closer to the separator axis to improve flow distribution, then manufacturing precision is improved, but resuspension of settled solids increases
Solution Approach 1:
The patent positions the inlet opening asymmetrically relative to the separator axis, specifically offsetting it from the central axis. This asymmetric positioning creates a controlled flow pattern that distributes wastewater uniformly across the tray surface while directing flow away from the settled solids region, thereby preventing resuspension while maintaining flow distribution uniformity
Solution Approach 2:
The invention creates different flow conditions in different regions of the tray. The inlet opening is positioned to generate a specific flow trajectory that provides gentle, uniform distribution over the settling surface while avoiding direct impingement on settled solids. This localized flow quality control prevents resuspension in the settling zone while maintaining good distribution
3Productivity
If the settling portion has a steep taper to improve settling efficiency, then productivity is improved, but the cross-sectional area becomes insufficient leading to blockages
Solution Approach 1:
The patent employs a curved, concave settling portion rather than a straight taper. The curved surface provides adequate cross-sectional area throughout the settling zone, preventing blockages, while still maintaining sufficient slope to enable efficient particle settling. The curvature allows the surface to taper gradually without creating narrow constrictions
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 reduces resuspension of solids and minimizes blockages, improving the underflow and total collection efficiencies by optimizing the flow dynamics within the separator.
Implementation Method 1
the low energy vortex allows grit particles entrained by the flow to settle on the sloping inner surface of each tray whereupon the particles gravitate towards and pass through the openings in the trays
Implementation Method 2
The inlet opening is arranged to provide a tangential inlet such that a low energy vortex flow is established between adjacent trays
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
There is described a separator 202, 302 for separating solids from a solid-liquid mixture, the separator 202, 302 having a separator axis 208, 308 and comprising a tray assembly 204, 304, the tray assembly 204, 304 comprising a plurality of nested tray units 210, 310, wherein each tray unit 210, 310 comprises: an outlet edge 214, 314 defining an outlet opening 234, 334, the outlet opening 234, 334 having a centroid 236, 336 through which the separator axis 208, 308 extends; an overflow edge 212, 312 defining an overflow opening 232, 332; and a surface 216, 316 extending between the outlet edge 214, 314 and the overflow edge 212, 312, the surface 216, 316 defining an internal volume 215, 315 of the tray unit 210, 310 and an inlet opening 230, 330 for receiving a respective portion of the solid-liquid mixture into the internal volume 215, 315, the surface 216, 316 having a settling portion 226, 326, wherein the settling portion 226, 326 faces the separator axis 208, 308 and tapers inwardly toward the separator axis 208, 308 in a direction 235, 335 toward the outlet edge 214, 314, wherein a cross-sectional area bounded by the settling portion 226, 326 and defined perpendicular to the separator axis 208, 308 is at a maximum on a first plane 238, 338 of the tray unit 210, 310, wherein a cross-sectional profile 241, 341 of the settling portion 226, 326 on the first plane 238, 338 has a centroid 240, 340, wherein a first distance d1 between the inlet opening 230, 330 and the centroid 240, 340 of the cross-sectional profile 241, 341 is greater than a second distance d2 between the inlet opening 230, 330 and the separator axis 208, 308.