Pneumatic Fire Detector with Electronic Pressure Sensor
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Solution Overview
Problem
Conventional pneumatic fire detectors operate in only three discrete states (normal, alarm, or fault) and lack trend monitoring capabilities, which can lead to costly engine repairs and false alarms in aerospace applications.
Innovation Solution
A pneumatic sensing apparatus with a sensor tube containing pressurized gas, a pressure switch, and a signal transducer using a variable resistor and controller to detect temperature and pressure changes, providing early warnings of overheat conditions and distinguishing between normal and hazardous situations through continuous resistance measurement and trend analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional pneumatic detectors use only discrete pressure switches, then the device structure is simple, but the measurement precision and information completeness are insufficient
Solution Approach 1:
The patent replaces the traditional mechanical pressure switch system with an electronic pressure sensor and signal transducer system. The pressure sensor converts pressure changes into electrical signals, which are then processed by a controller to determine temperature conditions. This substitution enables continuous analog measurement instead of discrete switching, significantly improving measurement precision while maintaining reasonable device complexity through integrated electronic components.
Solution Approach 2:
The patent introduces a dynamic measurement approach by continuously monitoring pressure changes through the sensor and transducer system. Instead of static threshold switching, the system dynamically tracks pressure variations over time, allowing for trend analysis and early detection of temperature changes. This dynamic capability enables the system to distinguish between normal fluctuations and hazardous conditions, improving both precision and information completeness.
2Loss of information
If pneumatic detectors provide only three discrete states, then the device complexity is low, but the loss of information about temperature trends is significant
Solution Approach 1:
The patent implements a feedback mechanism where the pressure sensor continuously monitors gas pressure, the transducer converts these readings into electrical signals, and the controller processes the signals to determine temperature conditions. This closed-loop feedback system provides continuous information about temperature trends, enabling the detection of gradual heating patterns before they reach alarm thresholds. The feedback loop maintains information completeness while managing complexity through systematic signal processing.
Solution Approach 2:
The patent enables preliminary detection of temperature trends by continuously monitoring pressure changes before they reach critical alarm levels. The system can identify early signs of overheating through gradual pressure increases, allowing for preventive action before a fire condition develops. This preliminary action capability reduces information loss by providing advance warning while maintaining manageable device complexity through the use of standard sensor and controller components.
3Reliability
If early warning detection is added to detect deflection before alarm condition, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The patent replaces the mechanical alarm switch system with an electronic detection system comprising a pressure sensor, signal transducer, and controller. The pressure sensor detects subtle pressure changes corresponding to early deflection, the transducer converts these changes into electrical signals, and the controller analyzes the signals to determine whether an early warning condition exists. This electronic substitution improves reliability by enabling detection of subtle changes that mechanical switches cannot detect, while managing complexity through integrated circuitry.
Solution Approach 2:
The patent introduces dynamic monitoring capability that continuously tracks pressure changes to detect early warning conditions. The system dynamically evaluates pressure trends and can distinguish between normal operational variations and early signs of hazardous conditions. This dynamic approach improves reliability by providing early warning of developing problems while managing complexity through software-based analysis in the controller rather than additional mechanical components.
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
Enables early detection of overheat conditions, reducing the risk of fires and preventing costly repairs by providing trend monitoring and discrimination against false alarms, thus enhancing safety and reducing operational downtime.
Implementation Method 1
When the sensor tube portion of the pneumatic detector in its final form is exposed to high temperature, the pressure inside will rise
Implementation Method 2
The signal transducer can include a strain gauge
Implementation Method 3
The variable resistor is configured to measure a change in resistance wherein a change in resistance is indicative of a temperature and pressure change of the pressurized gas
Data Source
Figure 1~2
Figure 3~4
AI summary
A pneumatic sensing apparatus for use in an overheat or fire alarm system includes a sensor tube containing a pressurized gas in communication with a pressure sensor configured to sense a temperature variation based on changes of the pressurized gas. A pressure switch (100) is coupled to the pressure sensor (110). The pressure switch (100) includes a signal transducer (126) configured to provide an output indicative of an overheat or fire alarm condition.