System and method for determining an abnormal condition of a water heater

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Solution Overview

Problem

Water heater systems often shut down due to false detection of abnormal conditions, leading to unnecessary shutdowns and potential operational inefficiencies.

Innovation Solution

Implementing a method that uses temperature sensors and controllers to filter temperature data with different time constants, determining if temperatures cross specific thresholds and assessing the rate of change to accurately identify abnormal conditions before initiating a shutdown procedure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If temperature thresholds are used to detect abnormal conditions, then safety is improved, but false shutdowns increase

Engineering Contradiction:

ImprovesafetyVSAvoidoperational continuity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies dynamics by making the filtering characteristics adaptive rather than static. The controller dynamically adjusts the time constant based on the operational state of the water heater, using a first time constant during normal operation and a second time constant during abnormal conditions. This dynamic adjustment allows the system to respond appropriately to different operational states, reducing false shutdowns while maintaining safety.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of the filtering system by using different time constants depending on the operational state. During normal operation, a first time constant is used for standard filtering, while during abnormal conditions, a second time constant is applied. This parameter change allows the system to optimize its detection accuracy for different states, reducing false positives while maintaining reliable abnormal condition detection.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If filtering with a single time constant is used, then processing is simplified, but detection accuracy under varying conditions deteriorates

Engineering Contradiction:

Improvefiltering processVSAvoidtemperature detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The filtering process is made dynamic by switching between different time constants based on operational state. The controller monitors the water heater's operation and automatically adjusts the filtering characteristics, using a first time constant for normal conditions and a second time constant for abnormal conditions. This dynamic approach maintains relatively simple processing while significantly improving detection accuracy across varying operational conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the filtering parameter (time constant) based on the operational state of the water heater. By using a first time constant during normal operation and a second time constant during abnormal conditions, the system adapts its filtering characteristics to match the current state, thereby improving temperature detection accuracy without requiring a completely complex filtering system.

Inventive Principle:

Principle #35Parameter changes

3Speed

If rapid response to temperature changes is implemented, then safety response is improved, but false detection of normal fluctuations increases

Engineering Contradiction:

Improveresponse speedVSAvoiddetection accuracy

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The system dynamically adjusts its response characteristics by using different time constants for different operational states. During normal operation, the first time constant provides standard filtering that allows legitimate temperature changes to pass through. During abnormal conditions, the second time constant provides enhanced filtering that distinguishes between normal fluctuations and genuine abnormal conditions, maintaining reliable detection while reducing false positives.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the response parameter (time constant) based on operational state to balance speed and accuracy. By using a first time constant for normal conditions and a second time constant for abnormal conditions, the system adjusts its sensitivity to temperature changes, ensuring rapid response to genuine abnormalities while filtering out normal operational fluctuations that would otherwise trigger false detections.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10465945B2System and method for determining an abnormal condition of a water heater

Publication Date: 2019.11.05 A O SMITH

AI summary

A method of determining an abnormal condition in a water heater. The method including sensing, via a temperature sensor, a plurality of temperatures and filtering, using a first time constant, the plurality of temperatures to produce a first plurality of filtered temperatures. The method further including determining, via a controller, if at least one temperature of the first plurality of filtered temperatures crosses a first temperature threshold, and when at least one temperature of the first plurality of filtered temperatures crosses a second temperature threshold, filtering, using a second time constant, the plurality of temperatures to produce a second plurality of filtered temperatures. The method further including initiating, via the controller, a shutdown procedure when at least one temperature of the second plurality of filtered temperatures, crosses a third temperature threshold.