Off-Time Detector for Stand-Alone Ice Maker Compressor Restart Control

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Solution Overview

Problem

Stand-alone ice makers face challenges with compressor overheating due to pressure differentials when restarted after being powered down, leading to delayed ice production and consumer frustration, and are often costly.

Innovation Solution

Incorporating an off-time detector using a parallel connected resistor and capacitor to determine if the compressor has been unpowered long enough to prevent overheating, allowing for quick start-ups and reducing the time to first ice production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the compressor is restarted immediately after being powered down, then the time to first ice production is reduced, but the compressor may overheat due to pressure differential

Engineering Contradiction:

Improvetime to first ice productionVSAvoidcompressor overheating prevention

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The off-time detector performs preliminary detection of the compressor's operational state before allowing restart. By detecting whether the compressor has been off for a sufficient time period, the system determines whether it is safe to restart, thus preventing overheating while enabling quick restart when conditions permit

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The off-time detector provides feedback about the compressor's recent operational history to the control system. This feedback mechanism allows the controller to make informed decisions about restart timing, balancing the need for quick ice production with compressor protection

Inventive Principle:

Principle #23Feedback

2Reliability

If a delay is implemented before starting the compressor after powering up, then compressor overheating is prevented, but the time to first ice production increases

Engineering Contradiction:

Improvecompressor overheating preventionVSAvoidtime to first ice production

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system dynamically adjusts the restart timing based on actual compressor conditions rather than using a fixed delay. The off-time detector continuously monitors the compressor state, and the controller adapts the restart decision in real-time, allowing immediate restart when safe and implementing delays only when necessary to prevent overheating

Inventive Principle:

Principle #15Dynamics

3Reliability

If traditional overheating protection methods are used, then compressor safety is ensured, but the system becomes more expensive and complex

Engineering Contradiction:

Improvecompressor safetyVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The off-time detector serves as an intermediary component between the power supply and the compressor control system. It provides a simple time-based detection mechanism that bridges the gap between power state changes and compressor operation decisions, enabling safe operation without complex monitoring systems

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The off-time detector uses simple, inexpensive electronic components (timers and sensors) rather than complex expensive protection systems. This approach provides adequate protection for the application while keeping the system cost-effective and accessible to typical consumers

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 decreases the time to first ice production while preventing compressor overheating, reducing consumer frustration and increasing ice production efficiency, and is cost-effective compared to traditional solutions.

Implementation Method 1

an off-time detector configured to provide a signal indicative of whether the ice maker has been unpowered for a time period sufficient to begin ice production without overheating

Methodology Applied

Scientific EffectElectrical timing:

Implementation Method 2

a pump in fluid communication with the second storage volume for actively flowing water from the water tank

Methodology Applied

Scientific EffectMechanical pumping: Pump

Implementation Method 3

the compressor has previously built up an appropriate operating pressure differential

Methodology Applied

Scientific EffectCompression: Compression

Data Source

PatentUS10520236B2Off-time detector for stand-alone ice making appliances

Publication Date: 2019.12.31 HAIER US APPLIANCE SOLUTIONS INC

AI summary

Stand-alone ice making appliances and methods of controlling stand-alone ice making appliances are provided. An appliance includes a container defining a first storage volume for receipt of ice, a water tank defining a second storage volume for receipt of water, and a pump in fluid communication with the second storage volume. The appliance further includes an ice maker which is in fluid communication with the pump for receiving water from the pump. The appliance further includes an off-time detector configured to provide a signal indicative of whether the ice maker has been unpowered for a time period sufficient to begin ice production without overheating.