Gas Shutoff Device Valve Timing for Ultrasonic Sensor Errors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gas shutoff devices can incorrectly determine flow rate or sensor abnormalities due to non-uniform gas layers caused by mixing different gases or changes in gas distribution during installation or replacement, leading to unnecessary valve closure and unavailability of gas.
Innovation Solution
A valve-closing timer section is introduced to allow for a predetermined time to accept a release input, enabling the valve to reopen if the closure was due to erroneous determination, ensuring gas availability during construction and maintaining safety by preventing false releases after the set time has passed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If abnormal flow rate determination and sensor abnormality determination are performed continuously to ensure safety, then gas safety is improved, but false valve closure occurs during gas mixing or installation leading to gas unavailability
Solution Approach 1:
The system dynamically changes the response to abnormality determination based on timing. Within a predetermined time period after installation or gas type change, the valve can be reopened by operation input even if abnormality is detected. After this period, normal strict determination is applied. This dynamic time-based policy resolves the contradiction by being lenient when false abnormalities are likely (improving availability) while maintaining strict safety checks after stabilization.
Solution Approach 2:
The system performs preliminary abnormality determination immediately after installation or gas type change, recognizing that non-uniform gas layers may cause false positives. By anticipating the likelihood of false abnormalities during this initial period, the system allows for operational override within a set time window, preventing unnecessary gas unavailability while still monitoring for true abnormalities.
2Reliability
If the valve remains closed during abnormality determination to ensure safety, then gas leakage prevention is improved, but construction work must be stopped causing loss of time
Solution Approach 1:
The valve closure policy is made dynamic based on the time elapsed since installation or gas type change. Within the predetermined time period, the valve can be reopened by operation input despite abnormality determination, allowing construction to continue. After this period, the valve remains closed upon abnormality detection to prevent leakage. This resolves the contradiction by allowing time-dependent flexibility in safety enforcement.
Solution Approach 2:
The predetermined time period acts as an intermediary buffer between immediate safety closure and long-term safety enforcement. During this intermediate period, the system accepts operation input to reopen the valve, serving as a mediator that allows construction continuity while still maintaining abnormality monitoring, thus balancing safety with construction time requirements.
3Reliability
If strict abnormality determination is applied immediately after gas type change or installation, then false abnormalities are prevented, but measurement precision is reduced due to non-uniform gas layer
Solution Approach 1:
The determination policy dynamically adapts to the gas layer uniformity status. Immediately after gas type change or installation when non-uniformity is expected, the system allows operation input to override abnormality determination within a predetermined time window. After this period, when gas distribution is assumed uniform, strict determination is applied. This dynamic approach prevents false abnormalities during measurement instability while maintaining precision after stabilization.
Solution Approach 2:
The system performs preliminary monitoring without strict enforcement during the initial period after installation or gas change, anticipating that measurement precision will be reduced due to non-uniform gas layers. By delaying strict abnormality determination until the gas layer stabilizes, the system avoids false positives caused by temporary measurement inaccuracies.
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 allows for the gas to be made available again by releasing erroneous determinations within a given time, ensuring construction can continue while maintaining safety by preventing false releases after the set time, thus securing the gas shutoff device's safety.
Implementation Method 1
an unexpected flow rate from the measuring condition may be detected due to the propagation of the ultrasonic waves differently from that when the gas is distributed uniformly
Data Source
AI summary
With a conventional gas shutoff device, a non-uniform gas layer can be produced by a shift in the amount of heat or by mixing of a gas of a different type from the gas currently in use during installation or replacement, and an unexpected flow volume may be detected due to a disruption in the propagation of ultrasonic waves, resulting in an erroneous judgment of a flow volume abnormality or a sensor abnormality. With the invented gas shutoff device, a closing timing unit (14) begins timing based on a valve-close signal which is output with a flow volume abnormality or a sensor abnormality, and outputs a valve-open signal to a valve drive unit (12) if a cancellation input is received from outside within a set time. Thus, even when a non-uniform gas layer is produced by a shift in the amount of heat or by mixing of a gas of a different type from the gas currently in use during installation or replacement, an unexpected flow volume is detected due to a disruption in the propagation of ultrasonic waves, resulting in an erroneous judgment of a flow volume abnormality or a sensor abnormality, and the valve is closed, the erroneous judgment is resolved and reuse of the gas is enabled if within a prescribed time.