Hinged Separating Screen with Cut-Outs for Wastewater Back-Flushing
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Solution Overview
Problem
Wastewater lifting stations face operational disruptions due to clogging of separating screens caused by increasing amounts of short and long fibrous materials and fats, leading to incomplete release of solids during flushing, which results in undesirable stoppage times.
Innovation Solution
The separating screen in the wastewater lifting station is designed with a hinge-remote peripheral region featuring cut-outs open towards the outside, configured in a comb-type manner, allowing for effective removal of fibrous and elongate solids during back-flushing by creating a passage for the flushing stream to strip away adhering materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the separating screen is configured as a solid structure to effectively separate bulky materials, then separation efficiency is improved, but the screen becomes clogged by fibrous materials and fats, leading to operational disruptions
Solution Approach 1:
The separating screen is segmented with cut-outs in the hinge-remote peripheral region, dividing the screen surface into multiple sections. This segmentation prevents fibrous materials from accumulating across the entire screen surface, allowing the flushing stream to access and remove solids more effectively through the cut-outs, thereby maintaining operational continuity while preserving separation efficiency.
Solution Approach 2:
The screen structure has non-uniform properties: the hinge-remote peripheral region contains cut-outs while other regions remain solid. This local variation in quality allows the screen to maintain high separation efficiency in solid regions while enabling effective flushing and preventing clogging in the cut-out regions, resolving the contradiction between separation performance and operational continuity.
2Reliability
If the separating screen is designed with a solid surface to retain all solids, then separation completeness is improved, but solids cannot be completely released during flushing, causing stoppage times
Solution Approach 1:
The cut-outs in the screen are designed in advance to provide pathways for the flushing stream. This preliminary structural arrangement ensures that when flushing occurs, the stream can immediately access and remove solids without obstruction, preventing the need for operational stoppages while maintaining complete separation during normal operation.
Solution Approach 2:
The cut-outs act as intermediaries between the flushing stream and the solids retained on the screen. These openings provide a mediating pathway that allows the flushing stream to reach and remove solids that would otherwise be trapped against the solid screen surface, enabling complete solid release without operational stoppages.
3Strength
If the separating screen is made with fewer openings to improve structural strength, then screen durability is improved, but fibrous materials clog the screen more easily, increasing maintenance needs
Solution Approach 1:
Rather than reducing the overall number of openings or making the screen more porous, the invention segments the screen by adding cut-outs in specific regions. This maintains the structural strength of the main screen body while creating localized flushing pathways that prevent fibrous material accumulation, reducing maintenance frequency without compromising strength.
Solution Approach 2:
The screen maintains high structural strength in the majority of its area while introducing cut-outs only in the hinge-remote peripheral region. This local modification provides sufficient flushing capability to prevent clogging by fibrous materials without requiring a reduction in overall screen strength or structural integrity.
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 design prevents clogging of the separating screen and ensures complete removal of solids, reducing maintenance needs and extending the service life of the wastewater lifting station by allowing fibrous materials to be released during flushing, thus minimizing operational disruptions.
Implementation Method 1
the separating screen subdivides the bulky-material collection container into a bulky-material loaded region and a bulky-material free region
Implementation Method 2
cleaning of the separating screen by back-flushing, in particular using pre-cleaned wastewater, is performed in a manner which is flawless and as complete as possible
Data Source
AI summary
A wastewater lifting station is provided, in which at least one solids collection tank contains at least one screen for guiding wastewater therethrough and retain solids. The screen divides the solids collection tank into a region containing solids and a region free of solids, and is connected in a pivotable manner by at least one hinge to a flange of the solids collection tank. The screen in an edge region away from the hinge has a rake of comb-type webs and holes that are open on one side in the screen plane. The wastewater containing solids flows through a feed into the collection tank, is filtered through the screen, and the wastewater that is free of solids is collected in a tank downstream. When the wastewater lifting station pumps, the wastewater that is free of solids is pumped by a pump in counterflow through the screen into a pressurized line while the feed is shut off by a check valve, and the screen pivots about the hinge and is back-flushed during the process. Reliable cleaning of the screen, even of fibers, is achieved during pumping owing the rake shape and the pivoting of the screen.