Decanter Cover Element Buoyancy Control for Sludge Contamination
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Solution Overview
Problem
Existing clear water decanters in sewage treatment plants face contamination issues due to 'floating sludge' entering the inlet pipe and outlet pipe, leading to undesirable contamination of the clear water.
Innovation Solution
A decanter with a displacement device featuring a buoyancy element that automatically moves a cover element from a closed to an open position as the inlet pipe is lowered, ensuring the cover element is below the floating sludge layer, preventing contamination by only allowing clear water to enter the inlet pipe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the inlet pipe is lowered to extract clear water from the settling tank, then clear water can be drawn off effectively, but floating sludge enters the inlet pipe through the inlet openings causing contamination
Solution Approach 1:
The cover element is pre-positioned to close the inlet openings before the inlet pipe enters the floating sludge layer. The displacement device is pre-configured with the cover element in the closed position, which is automatically opened only when the inlet pipe reaches the clear water layer, preventing sludge contamination from the outset
Solution Approach 2:
The cover element acts as an intermediary between the inlet pipe and the floating sludge. It selectively blocks the inlet openings when positioned over them, preventing direct contact between the inlet pipe and contaminated sludge, while allowing clear water intake when opened
2Object-affected harmful factors
If a cover element is fixed to the inlet pipe to block floating sludge, then sludge entry is prevented, but clear water cannot be drawn off through the inlet openings
Solution Approach 1:
The cover element transitions from a static barrier to a dynamic component that changes position based on operational needs. It is movable between a closed position (blocking inlet openings to prevent sludge entry) and an open position (allowing clear water flow), controlled by the displacement device in response to inlet pipe depth
Solution Approach 2:
The displacement device replicates the depth-sensing function of the inlet pipe positioning system. By using the same positioning mechanism to trigger cover element opening, the system ensures synchronized operation without requiring separate control systems
3Object-affected harmful factors
If the cover element remains in the closed position to prevent sludge entry, then contamination is avoided, but clear water extraction is prevented
Solution Approach 1:
The manual or complex mechanical control system for opening/closing the cover element is replaced with a simple buoyancy-based displacement device. This passive mechanical system automatically responds to water level changes, eliminating the need for active control mechanisms while ensuring timely opening for clear water extraction
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
Effectively prevents the entry of 'floating sludge' into the clear water extraction system, ensuring the quality of extracted water by using buoyancy forces to displace the cover element into the open position once the inlet pipe reaches the clear water layer, thereby maintaining the integrity of the clear water.
Implementation Method 1
The displacement device comprises at least one buoyancy element, which, as a result of the buoyancy element being immersed, for example, in the water horizon of the clear water and thus below the floating sludge layer, moves the cover element into its inlet position
Implementation Method 2
The displacement device is designed, for example, geometrically and in terms of weight, such that the cover element is in the closed position due to gravity before being immersed in the settling tank
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3a~3b
AI summary
The invention relates to a clarified water withdrawing device (decanter 10) for a clarification facility, comprising an inlet pipe (18), which can be moved between a parked position and a removal position and through which at least one inflow opening (28) passes, via which clarified water can be withdrawn out of a clarification tank (12) and can be conducted into an outlet pipe (20), and comprising at least one cover element (26), which is arranged so as to overlap with the at least one inflow opening (28) in an inflow position, wherein the cover element (26) can be moved between a closed position and the inflow position by means of a movement device (24) that comprises at least one flotation element (34), by means of which the cover element (26) can be moved into the closed position as a result of an immersion of the flotation element (34) into the wastewater.