Rotating Electrode Sampling for Slip Ring Interruption Detection
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Solution Overview
Problem
Conventional measuring devices for chlorine concentration in water face challenges in accurately detecting fluctuations in current magnitude due to variations in contact states between the slip ring and brush, leading to difficulties in understanding the device's state and increased computational burden.
Innovation Solution
The measuring device employs a dual-sampling period approach using a first and second sampling period to detect voltage fluctuations and interruptions, allowing for efficient detection of short-duration voltage fluctuations while reducing computational burden, and includes features like variable rotational velocity and direction of the electrode to extend component life and maintain device stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single sampling period is used to measure current magnitude, then the measurement process is simple, but short-duration voltage fluctuations due to slip ring contact changes cannot be detected
Solution Approach 1:
The sampling process is divided into two distinct sampling periods: a first sampling period for high-frequency detection of voltage fluctuations and slip ring contact state, and a second sampling period for lower-frequency measurement of current magnitude for concentration calculation. This segmentation allows each sampling period to be optimized for its specific purpose, enabling detection of short-duration fluctuations without requiring the entire system to operate at high frequency.
Solution Approach 2:
The system employs periodic sampling with two different periods alternating or operating in conjunction. The first sampling period operates at a higher frequency to periodically check for interruptions and contact changes, while the second sampling period operates at a lower frequency for routine measurements. This periodic multi-rate sampling enables the system to adapt to different measurement needs at different times.
2Measurement precision
If high-frequency sampling is used to detect short-duration voltage fluctuations, then detection capability improves, but computational burden increases
Solution Approach 1:
Computational tasks are segmented and assigned to different sampling periods. The first sampling period performs only interruption detection and contact state monitoring, which requires minimal computation. The second sampling period performs the full concentration calculation using the average current magnitude. This segmentation prevents the computationally intensive concentration calculation from running at every high-frequency sampling point.
Solution Approach 2:
The first sampling period performs only partial measurement (interruption detection) rather than full concentration calculation. This partial action at high frequency is sufficient to detect contact issues, while the full measurement is performed less frequently at the second sampling period, reducing overall computational burden while maintaining detection capability.
3Ease of operation
If the electrode rotates at constant speed, then operation is simple, but component abrasion increases and device life decreases
Solution Approach 1:
The electrode rotation speed is changed from constant to variable, dynamically adjusted based on operational conditions. The controller varies the rotation speed within a predetermined range to optimize between measurement accuracy (requiring sufficient rotation) and component life (benefiting from reduced rotation). This dynamic adjustment allows the system to adapt rotation speed to current needs rather than maintaining fixed high-speed rotation.
Solution Approach 2:
The rotation speed parameter is changed from a fixed value to a variable parameter with a predetermined range. The controller modifies this parameter based on operational requirements, allowing the system to reduce rotation speed during periods when high measurement frequency is not needed, thereby reducing mechanical stress and extending the life of rotating components while maintaining measurement capability when required.
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 enables precise detection of chlorine concentration with reduced computational load, facilitates timely maintenance, extends component life, and improves operational convenience by stabilizing the diffusion current and reducing abrasion.
Implementation Method 1
a first electrode (21) configured to be immersed in a sample water (402) containing a measurement target and stored in a measuring tank (40)
Implementation Method 2
a voltage converter configured to convert the current flowing through the sample water into a voltage
Data Source
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AI summary
A measuring device (1) includes: a first rotating electrode (21) configured to be immersed in sample water stored in a measuring tank (40); a second electrode (22) configured to be immersed in the sample water; and a controller (10) configured to: cause a power source (20) to flow a current through the sample water between the first electrode (21) and the second electrode (22); detect, based on a first digital signal, an interruption, the interruption can occur due to degradation of a slip ring (25) or brush (24) that connect a measuring unit and the rotating electrode (21), whereby an analog signal fluctuates by no less than a predetermined value; and calculate, based on a second digital signal, a concentration of a measurement target in the sample water. The first digital signal is acquired by sampling the analog signal with a first sampling period. The analog signal is based on the current flowing through the sample water. The second digital signal is acquired by sampling the analog signal with a second sampling period that is longer than the first sampling period.