Rotating Electrode Control for Chlorine Sensor Wear Reduction
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Solution Overview
Problem
Conventional measuring devices for chlorine concentration in sample water have limitations in convenience, particularly in terms of electrode wear, slip ring abrasion, and operational efficiency, leading to reduced device lifespan and accuracy.
Innovation Solution
The measuring device incorporates a motor that can rotate in both clockwise and counterclockwise directions, with alternating velocity changes, and a control unit that adjusts rotational velocity based on operational modes to minimize electrode and slip ring wear, and includes granular members for cleaning and stabilization, thereby extending device lifespan and improving convenience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor rotates the first electrode continuously in one direction during standby mode, then the electrode remains positioned for measurement, but the slip ring is readily abraded and part life is reduced
Solution Approach 1:
The control unit controls the motor to rotate the first electrode periodically during standby mode rather than continuously, reducing slip ring abrasion while maintaining measurement readiness. The electrode is rotated at specific intervals to prevent fouling while minimizing wear on the slip ring connection.
2Reliability
If the motor rotates the first electrode at high speed continuously, then cleaning effectiveness is improved, but the electrode is readily stretched and life is reduced
Solution Approach 1:
The control unit controls the motor to rotate the first electrode at high speed periodically during cleaning mode rather than continuously, effectively removing fouling while minimizing cumulative stress on the electrode. The high-speed rotation is activated only when cleaning is required, preventing electrode stretching while maintaining cleaning effectiveness.
Solution Approach 2:
The control unit dynamically adjusts the rotational speed of the first electrode based on operational requirements. During cleaning mode, the electrode rotates at high speed to effectively remove fouling, while during normal operation, the speed is reduced or stopped to prevent electrode stretching and extend its life.
3Loss of time
If the motor rotates the first electrode at high speed during breaking in mode, then stabilization time after granular member replacement is shortened, but electrode and slip ring wear increases
Solution Approach 1:
The control unit controls the motor to rotate the first electrode at high speed periodically during breaking in mode after granular member replacement, rapidly stabilizing the system while limiting cumulative wear. The high-speed rotation is applied in controlled intervals rather than continuously, achieving quick stabilization while preserving electrode and slip ring life.
Solution Approach 2:
The control unit applies high-speed rotation during breaking in mode as a preliminary stabilization process after granular member replacement. This preliminary action quickly establishes optimal operating conditions, reducing the need for extended low-speed operation and thereby minimizing overall wear while achieving rapid stabilization.
4Reliability
If the motor rotates the first electrode in fixed direction only, then the operation is simple, but the electrode is stretched in one direction and life is reduced
Solution Approach 1:
The control unit controls the motor to rotate the first electrode in alternating directions during cleaning and breaking in modes rather than in a fixed direction. This reverse rotation approach prevents the electrode from being stretched consistently in one direction, extending its life while adding minimal complexity to the rotation control system.
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 solution prolongs the life of electrodes and slip rings, enhances operational convenience, and reduces calculation errors by stabilizing the diffusion current and surface state of electrodes, improving the overall efficiency and accuracy of chlorine concentration measurement.
Implementation Method 1
The motor may rotate either clockwise or counterclockwise as a forward direction when the rotational velocity is a positive value and rotate in a direction opposite to the forward direction when the rotational velocity is a negative value. The control unit may control the rotation of the motor so as to alternately change the rotational velocity between a positive value and a negative value.
Implementation Method 2
a slip ring electrically connected to the first electrode or the rotating first electrode
Implementation Method 3
the control unit may control the rotation of the motor such that the absolute value of the rotational velocity when operating in a standby mode where the concentration of a measurement target in the sample water is not calculated is made smaller than the absolute value of the rotational velocity when operating in the measuring mode. Thus, a slip ring electrically connected to the first electrode or the rotating first electrode is less readily abraded.
Implementation Method 4
measures a current flowing in the sample water by controlling a power source and an ammeter, and calculates a concentration of a measurement target in the sample water based on a magnitude of the measured value of the current
Data Source
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AI summary
A measuring device includes: a first electrode (21) and a second electrode (22) immersed in sample water stored in a measuring tank (40); a motor (30) configured to rotate the first electrode (21); and a controller (10) configured to operate, based on measurement results of current flowing through the sample water, in a measuring mode. In the measuring mode, the controller (10) is configured to calculate a concentration of a measurement target in the sample water. The motor (30) is configured to change a rotational velocity of the motor (30).