Heating Circuit Fault Discrimination in Household Appliances
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing heating circuit monitoring arrangements in household appliances cannot effectively discriminate between different types of faults in the heating circuit, leading to unnecessary appliance halts and increased power consumption.
Innovation Solution
A monitoring circuit arrangement with a resistive network and current sensor is used to assess faults in the heating circuit, allowing for precise discrimination between fault types and reducing power consumption by disconnecting the heating resistor when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a monitoring arrangement is implemented to detect faults in the heating circuit, then safety and reliability are improved, but power consumption increases even when the appliance is not operated
Solution Approach 1:
The monitoring arrangement is activated periodically or on-demand rather than continuously. The control unit enables the monitoring arrangement only when the appliance is operated or when fault detection is required, thereby eliminating continuous power consumption while maintaining reliability when needed
Solution Approach 2:
The monitoring system transitions from a static continuous monitoring state to a dynamic state where it can be enabled or disabled by the control unit based on operational conditions, optimizing the balance between reliability and power consumption
2Reliability
If monitoring arrangements are used to detect all possible faults, then safety is improved, but the ability to discriminate between dangerous and non-dangerous faults is lost, leading to unnecessary appliance halts
Solution Approach 1:
The monitoring arrangement is divided into multiple independent monitoring circuits, each dedicated to detecting specific types of faults (heating resistor faults, switch element faults, power supply faults). This segmentation enables the control unit to identify the exact nature and location of faults, discriminating between dangerous faults requiring appliance halt and non-dangerous faults allowing continued operation
Solution Approach 2:
The monitoring circuits provide feedback signals to the control unit indicating the specific type of fault detected. This feedback mechanism enables the control unit to make informed decisions about whether to halt the appliance or allow continued operation with reduced performance, thereby maintaining appliance availability when safe to do so
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
The solution enables accurate fault detection and discrimination, preventing unnecessary appliance halts and reducing power consumption by ensuring only necessary components are active when the appliance is not in use.
Implementation Method 1
a current sensor arranged to measure a current flowing through the resistive network and to feed an indication of the measured current to the control unit
Implementation Method 2
a heating circuit for heating a washing liquid and/or a drying air flow, the heating circuit being connected to (AC) voltage distribution lines distributing (AC) power inside the appliance and comprising at least one heating resistor
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A washing and/or drying appliance, comprising a heating circuit (140) for heating a washing liquid and/or a drying air flow, the heating circuit being connected to voltage distribution lines (105a,105b) distributing power inside the appliance and comprising at least one heating resistor (205) in series to switch means (210a,210b) controlled by an appliance control unit (125) for selectively energizing the heating resistor when required. The switch means of the heating circuit comprise a first and a second switches (210a,210b) in series to the heating resistor, the heating resistor being interposed between the first and second switch. A monitoring circuit arrangement is associated with the heating circuit, said monitoring circuit arrangement comprising a resistive network including a first resistor (R1) connected to the heating circuit so as to be bypassed when the first switch is closed, the heating resistor, and a second resistor (R2) connected to the heating circuit so as to be bypassed when the second switch is closed, the monitoring circuit arrangement further comprising a current sensor (240) arranged to measure a current flowing through the resistive network and to feed an indication of the measured current to the control unit. The monitoring unit is configured for assessing possible faults of the heating circuit based on the indication of the measured current.