Blending Unit Control During Resin Tank Regeneration
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Solution Overview
Problem
Existing water softening systems face challenges in maintaining a consistent water hardness during regeneration, leading to operational interruptions and increased salt consumption due to the complexity of controlling partial flows and pressure changes in the system.
Innovation Solution
A method that modifies the dependency of partial flow ratios in the control device with a correction function during regeneration, allowing for automatic adjustment of the blending device to maintain desired water hardness without experimental feedback, using a system-specific dependency stored in the control device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the blending device is adjusted based on stored system-specific dependency, then the control effort is reduced, but pressure changes during regeneration cause deviations in blended water hardness from the desired value
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing correction values in a lookup table that compensate for pressure changes during regeneration. Instead of reacting to hardness deviations after they occur, the system proactively adjusts the blending ratio based on the regeneration state, preventing hardness deviations before they affect water quality.
Solution Approach 2:
The patent implements feedback by monitoring the regeneration state of filter elements and using this information to dynamically adjust the blending device. The control device receives feedback about which filter elements are being regenerated and automatically modifies the blending ratio to maintain consistent blended water hardness throughout the regeneration cycle.
2Reliability
If multiple filter elements are regenerated sequentially to maintain continuous soft water supply, then operational interruptions are avoided, but the control system becomes more complex due to need to track multiple regeneration states
Solution Approach 1:
The patent applies segmentation by dividing the filter system into multiple independently regenerable filter elements. This allows the system to regenerate one element at a time while others continue to provide softened water, ensuring continuous supply. The control device tracks the regeneration state of each segment separately and adjusts blending accordingly.
Solution Approach 2:
The patent implements periodic action through oscillating operation, where filter elements are regenerated in alternating sequences. While one element undergoes regeneration, another is in service, and they switch roles periodically. This rhythmic alternation maintains continuous soft water supply while simplifying the control logic compared to tracking arbitrary multiple regeneration states.
3Measurement precision
If experimental determination of partial flows with feedback is used, then precise maintenance of target water hardness is achieved, but the apparatus and control become very laborious and complex
Solution Approach 1:
The patent applies this principle by replacing complex continuous measurement and feedback systems with a simpler lookup table approach. Instead of using expensive and complex experimental determination of partial flows with real-time feedback, the system uses pre-calculated correction values stored in memory that provide sufficient accuracy without the need for complex measurement apparatus or continuous computational feedback.
Solution Approach 2:
The patent changes the control parameter from continuous experimental determination of partial flows to discrete lookup table indices based on regeneration state. By transforming the control approach from continuous measurement to discrete pre-calculated values, the system achieves adequate precision while dramatically reducing apparatus and control complexity.
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 approach ensures precise control of blended water hardness, reducing operational interruptions and salt consumption by accounting for pressure changes and flow conditions, maintaining the desired water hardness with reduced equipment and computational complexity.
Implementation Method 1
The hardeners contained in the water (calcium and magnesium ions) are exchanged for sodium ions in an ion exchange resin.
Data Source
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AI summary
The invention relates to a method for operating a water softening system (1) wherein the water softening system (1) comprises a water softening device (5), a sensor (4) for measuring a raw water hardness or an agent for entering a raw water hardness, an automatically adjustable blending unit for mixing a blending water flow V(t)blend from a first, softened partial flow V(t)partsoft and a second partial flow V(t)part2raw carrying raw water, and an electronic controller (13) for controlling the adjustment position of the blending unit so that the water hardness in the blending water flow V(t)blend is adjusted to a predefined target value (SW), wherein the measured or entered raw water hardness is analyzed for controlling the adjustment position and is subordinate to a dependency, stored in the controller (13), of the ratios of the partial flows V(t)partsoft and V(t)part2raw on the adjustment position of the blending device, said dependency specific to the water softening system (1), characterized in that the water softening device (5) comprises a plurality of tanks (7a, 7b) having ion exchange resin (8), and that the specific dependency of the ratios of the partial flows V(t)partsoft and V(t)part2raw on the adjustment position of the blending device is modified by a correction function stored in the controller (13) when a part of the tank (7a, 7b) is subjected to regeneration. By means of the method according to the invention, a desired target value of water hardness in a blending water flow is maintained with low effort in all operating situations.