Backwash Filter Impeller Flow Reversal Design
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Solution Overview
Problem
Existing backwash filters face issues with high flow resistance and complex structures, leading to pressure drops and inefficiencies in the backwashing process, especially when dealing with heavily polluted water, which results in the clogging of secondary filters used for backwashing.
Innovation Solution
A backwash filter design featuring an upper filter section with a smaller diameter than the lower section, an impeller with flat nozzles that rotate due to backwash water flow, and a mechanism that allows for efficient flow reversal with minimal pressure drop, ensuring effective cleaning of both filter sections without requiring additional drives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a valve and horizontal wall are used to separate filter chambers, then the filter can be divided into upper and lower sections, but the structure becomes complicated and pressure drop increases
Solution Approach 1:
The invention extracts and eliminates the horizontal wall and valve components from the system. Instead of using a complex valve mechanism to control flow between chambers, the patent uses the impeller's rotational movement to naturally direct water flow, thereby simplifying the overall structure while maintaining the ability to separate and clean different filter sections
Solution Approach 2:
Instead of using a valve to actively control and direct water flow between chambers, the invention inverts the approach by allowing water to flow freely through the horizontal wall during operation, and using the impeller's rotation during backwashing to reverse the flow direction. This passive approach eliminates the need for complex valve mechanisms
2Productivity
If a horizontal wall and valve are used to separate filter chambers, then flow direction can be controlled, but flow resistance increases and pressure drop occurs
Solution Approach 1:
The invention removes the valve component that caused flow resistance and pressure drop. During normal operation, water flows freely through the horizontal wall without any restrictive valve mechanisms, maintaining high flow rates and low pressure loss
Solution Approach 2:
Instead of using a valve to actively control flow direction (which creates resistance), the system allows natural flow during operation and uses the impeller's rotational kinetic energy during backwashing to invert the flow direction. This approach eliminates valve-induced pressure drops while maintaining flow control capability
3Productivity
If the impeller body diameter is larger than the upper filter section, then water flow is concentrated for better cleaning, but the impeller may interfere with filter element movement
Solution Approach 1:
The impeller body is designed with a diameter that is larger than the upper filter section to concentrate water flow and enhance cleaning efficiency in that specific local area. This localized enlargement of the impeller body creates a focused spray pattern that improves cleaning without requiring the entire impeller structure to be oversized
Solution Approach 2:
The patent specifies that the impeller is fixed to the housing in the axial direction, which prevents it from interfering with the axial movement of the filter element. This preliminary positioning constraint ensures that the enlarged impeller body can effectively concentrate water flow for cleaning while maintaining compatibility with the filter element's operational movement range
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 achieves low flow resistance in the operating position and enhanced cleaning efficiency during backwashing, effectively preventing clogging of the upper filter section and maintaining water flow while ensuring thorough cleaning of both filter sections.
Implementation Method 1
an impeller rotatable about the longitudinal axis of the filter element within the filter element, through which impeller water can be guided from the inside to the outside through a reduced angular range of the lower filter section in the backwash position
Implementation Method 2
With an impeller, the water is directed through nozzles or openings that only cover a limited angular range. This concentrates the water on this angular range. The flow speed and thus the cleaning effect during backwashing is then higher
Implementation Method 3
the upper filter section has a smaller diameter than the lower filter section, so that an annular shoulder is formed between the upper and lower filter sections, and the impeller is fixed to the housing in the axial direction
Data Source
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AI summary
A backwash filter for filtering drinking or process water, which can be switched from an operating position in which water is directed from the inlet (14; 214) through the filter (44, 244) to the outlet (16; 216) to a backwash position in which water is directed from the inlet (14; 214) in the reverse direction through the filter (44, 244) to an open outlet (92; 292), comprising a filter element (44; 244) axially movably guided between an upper and a lower stop, with an upper filter section (68; 268) and a lower filter section (66; 266), and an annular space (46; 282) arranged around the filter element (44; 244) and connectable to the inlet, and means for separating the annular space (46; 282) such that the lower The filter section (66; 266) in the operating position and the upper filter section (68; 268) in the backwash position can be connected to the inlet (16; 216) and flow is through it from the outside to the inside;and an impeller (100; 300) rotatable about the longitudinal axis of the filter element (44; 244) within the filter element (44; 244), through which, in the backwash position, water can be directed from the inside to the outside through a reduced angular range of the lower filter section (66; 266); is characterized in that the upper filter section (68; 268) has a smaller diameter than the lower filter section (66; 266), so that an annular shoulder (70; 270) is formed between the upper and lower filter sections, and the impeller (100; 300) is axially fixed to the housing and has a cylindrical, open-topped body whose diameter is larger than the diameter of the upper filter section (66; 266) and smaller than the diameter of the lower filter section (68; 268).