Heater Control via Dual-Threshold Temperature Detection
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Solution Overview
Problem
Existing heating devices cannot accurately distinguish between the presence and absence of a heating medium in the passage, leading to potential accidental heating and increased risk of smoke or fire when the medium is absent, as they lack the capability to detect empty passages effectively.
Innovation Solution
Incorporating a temperature detection system that differentiates between the presence and absence of a heating medium by using a temperature sensor to detect both the medium's temperature and the heater's surface temperature, with specific threshold-based energization control to prevent overheating and automatically switch off the heater when an empty passage is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a temperature sensor is used to detect temperature in the passage, then the temperature of the heating medium can be controlled within a proper range, but the system cannot distinguish between a state when heating medium exists and a state when no or little heating medium exists
Solution Approach 1:
The temperature detection function is segmented into two distinct detection modes: one for detecting heating medium temperature when medium is present, and another for detecting heater surface temperature when medium is absent. This segmentation allows the system to distinguish between the two states by selecting appropriate detection targets based on temperature characteristics.
Solution Approach 2:
The detection target parameter is changed dynamically based on temperature thresholds. When temperature exceeds a first threshold, the system switches from detecting heating medium temperature to detecting heater surface temperature, thereby changing the measurement parameter to identify the absence of heating medium.
2Ease of operation
If the energization controlling means only turns on/off heater energization based on heating medium temperature, then normal temperature control is achieved, but the system cannot detect accidental heating of an empty passage leading to smoke or fire
Solution Approach 1:
The system performs preliminary detection of heater surface temperature before allowing normal operation to proceed. By continuously monitoring heater surface temperature and comparing it with the first threshold, the system proactively identifies empty passage conditions before they lead to dangerous overheating, smoke, or fire.
Solution Approach 2:
A dual-feedback control mechanism is implemented: one feedback loop controls heater energization based on heating medium temperature, while another feedback loop monitors heater surface temperature to detect empty passage conditions. The second feedback loop provides safety feedback that overrides the first when dangerous conditions are detected.
3Productivity
If the temperature detection means only detects heating medium temperature, then normal heating operation is maintained, but the system lacks the capability to distinguish accidental heating conditions
Solution Approach 1:
The temperature detection means is designed with multi-functionality: it can detect both heating medium temperature (for normal operation control) and heater surface temperature (for empty passage detection). This universal detection capability allows a single sensor system to serve multiple detection purposes without compromising heating operation efficiency.
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 enhances the reliability of heating devices by accurately detecting accidental heating of empty passages and preventing fires by maintaining the heater in a standby or complete stop state when no medium is present, while ensuring normal operation when the medium is present.
Implementation Method 1
a heater (2) having a heating portion (6) that generates heat by energization
Implementation Method 2
a temperature sensor (26) for detecting temperature
Data Source
AI summary
Heating device includes: heater (2) with heating portion (6) generating heat by energization; housing (4) contains the heating portion and forms passage (18) for a heating medium between the housing and the heating portion; temperature detection means (26) detects, in the passage, temperature (T) inside the housing due to heat of the heating medium and the heating portion; and energization controlling means (40) for turning energization of the heater on/off depending on the temperature detected inside the housing. Energization of the heater is turned off to put the heater in an energization standby state if temperature detected inside the housing is equal to or greater than a first specified threshold (TS1), and is turned off to put the heater in an energization complete stop state if the temperature detected inside the housing in the energization standby state is equal to or greater than a second specified threshold (TS2).