Ice Maker Refrigerant Control Using Scraper Current Feedback

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Solution Overview

Problem

In ice-making systems, an excessive ice packing factor leads to pipe clogging and reduced efficiency, and existing control methods based on tank sensors are prone to abnormal communications, degrading the reliability of operation control.

Innovation Solution

A method for controlling the ice-making machine by adjusting the evaporation temperature of the refrigerant based on the drive current or pressure difference, including stopping and restarting the compressor operation to manage ice production and prevent pipe clogging, thereby improving reliability and reducing ice production stepwise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the ice packing factor in the tank is increased to improve refrigeration efficiency, then the refrigeration effect is enhanced, but the pipes in the ice-making system become clogged and ice making efficiency is degraded

Engineering Contradiction:
Improverefrigeration efficiencyVSAvoidpipe clogging
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system uses a current detector to monitor the drive current of the ice scraper motor. When the current exceeds a predetermined threshold, it indicates that ice accumulation is increasing and the ice packing factor is approaching dangerous levels. The control unit receives this feedback and automatically adjusts the refrigerant supply or stops the compressor to prevent pipe clogging, thus maintaining optimal refrigeration efficiency without harmful effects.

Inventive Principle:
Principle #23Feedback

2Reliability

If tank sensors (water-level sensor, ultrasonic sensor) are used to estimate ice amount and control the ice-making machine, then the ice packing factor can be managed, but abnormal communications with the facility side may cause degradation in reliability of operation control

Engineering Contradiction:
Improveoperation control reliabilityVSAvoidabnormal communications
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The system uses the ice scraper motor's own drive current as a self-diagnostic parameter to monitor ice accumulation. Instead of relying on external tank sensors that may have communication issues, the system leverages information already available from the ice scraper's operation. The drive current naturally increases as ice accumulation increases, providing a reliable, self-contained feedback mechanism that eliminates communication reliability problems with external sensors.

Inventive Principle:
Principle #25Self-service

3Object-affected harmful factors

If the evaporation temperature of the refrigerant is increased to reduce ice production and prevent pipe clogging, then the ice packing factor is controlled, but the refrigeration efficiency is reduced

Engineering Contradiction:
Improvepipe clogging preventionVSAvoidice making efficiency
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The system dynamically adjusts the evaporation temperature based on real-time monitoring of the ice scraper drive current. When the current is within the normal range, the system maintains optimal refrigeration efficiency. When the current exceeds the threshold indicating excessive ice accumulation, the system increases the evaporation temperature to reduce ice production. This dynamic adjustment allows the system to prevent pipe clogging only when necessary, maintaining high efficiency during normal operation.

Inventive Principle:
Principle #15Dynamics

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 enhances the reliability of operation control by preventing pipe clogging and reducing ice production efficiently, minimizing the risk of equipment damage and improving system reliability.

Implementation Method 1

ice by cooling a medium to be cooled, through heat exchange with a refrigerant in a refrigerant circuit

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

drive current for an ice scraper of the ice-making machine

Methodology Applied
Scientific EffectMechanical scraping: Mechanical Force

Data Source

PatentEP3904789B1Operation control method for ice maker
Publication Date: 2023.04.26 DAIKIN INDUSTRIES LTD
  • EP3904789B1 patent drawingFigure 1
  • EP3904789B1 patent drawingFigure 2
  • EP3904789B1 patent drawingFigure 3

AI summary

A method for controlling an operation of an ice-making machine 1 configured to make ice by cooling a medium to be cooled, through heat exchange with a refrigerant. The method includes increasing an evaporation temperature of the refrigerant to be supplied to the ice-making machine 1 when a drive current for an ice scraper 15 of the ice-making machine 1 is more than a first current value.