Impeller Speed Control via Motor Load Current Threshold

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Solution Overview

Problem

In desulfurization processes, impellers are often rotated at unnecessary high speeds due to overload reserve and empirically estimated abrasion states, leading to excessive wear and reduced cycle life.

Innovation Solution

A method to control the rotational speed of an impeller by reading the load current value of the motor and increasing the speed when it falls below a predetermined threshold, ensuring the load current value reaches or exceeds this threshold, thus preventing unnecessary abrasion and optimizing the impeller's operational speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the impeller is rotated at the maximum rotational speed to prevent motor overload, then the motor overload risk is reduced, but the impeller experiences unnecessary abrasion and its cycle life is degraded

Engineering Contradiction:
Improvemotor overload preventionVSAvoidimpeller cycle life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The impeller rotational speed is made dynamic rather than fixed at maximum. The control device adjusts the rotational speed based on real-time motor load current measurements, allowing the speed to vary between a lower limit value (for preventing overload) and an upper limit value (for reducing abrasion). This dynamic adjustment resolves the contradiction by optimizing speed based on actual operational conditions rather than consistently operating at maximum speed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The rotational speed parameter is changed from a constant maximum value to a variable parameter with adjustable limits. By setting both a lower limit (to prevent motor overload) and an upper limit (to reduce impeller abrasion), the system optimizes the rotational speed parameter based on motor load conditions, thereby resolving the contradiction between preventing overload and reducing wear.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the impeller rotational speed is set to a large value to prevent defective desulfurization, then desulfurization quality is improved, but the impeller is unnecessarily abraded

Engineering Contradiction:
Improvedesulfurization qualityVSAvoidimpeller abrasion
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The rotational speed is dynamically adjusted based on motor load conditions rather than being set at a constantly high value. The control device monitors load current and adjusts speed within optimized limits, ensuring sufficient speed for proper desulfurization while minimizing excessive speed that causes unnecessary abrasion.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control device uses feedback from motor load current measurements to adjust the impeller rotational speed. By continuously monitoring the load current and comparing it against predetermined thresholds, the system provides feedback control that maintains appropriate rotational speed for desulfurization quality while preventing excessive speed that would increase abrasion.

Inventive Principle:
Principle #23Feedback

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 prevents impeller abrasion and extends its cycle life by maintaining appropriate rotational speeds, improving desulfurization efficiency and reducing the need for frequent replacements.

Implementation Method 1

a motor rotationally driving the impeller

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2684966B1Impeller rotation speed control method
Publication Date: 2018.05.23 NISSHIN STEEL CO LTD
  • EP2684966B1 patent drawingFigure 1~3
  • EP2684966B1 patent drawingFigure 2

AI summary

A load current value I of a motor (4) rotationally driving an impeller (3) is read out when the impeller (3) is rotated at a predetermined set rotational speed X0, and the rotational speed of the impeller (3) is increased so that the load current value I becomes equal to or larger than a threshold value I0 when it is determined that the load current value I is smaller than the predetermined threshold value I0.