Gas Shutoff Pressure Sensing Without Flow-Path Through-Holes
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Solution Overview
Problem
Conventional gas safety devices using differential pressure sensors require a through-hole in the flow path, which can lead to gas leakage when the temperature rises due to a fire, and are costly due to the need for heat-resistant components.
Innovation Solution
A gas safety device employing absolute pressure sensors inside and outside the flow path to measure gas and atmospheric pressure, respectively, eliminating the need for a through-hole and allowing for a simpler, cheaper design with electronic components mounted on circuit boards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a differential pressure sensor is used to measure gas pressure, then gas supply pressure can be measured, but a through-hole is required in the flow path which causes gas leakage when temperature rises due to fire
Solution Approach 1:
The patent introduces atmospheric pressure as an intermediary reference value. Instead of directly measuring differential pressure through a through-hole in the flow path, the system measures absolute gas pressure and subtracts atmospheric pressure (measured outside the flow path) to calculate gas supply pressure. This eliminates the need for a through-hole while maintaining measurement capability.
Solution Approach 2:
The patent segments the pressure measurement function into two separate sensors: one measuring absolute gas pressure inside the flow path and another measuring atmospheric pressure outside the flow path. This segmentation allows each sensor to be positioned optimally without requiring a through-hole connection, thereby preventing gas leakage while maintaining measurement accuracy.
2Reliability
If heat-resistant components are added to prevent gas leakage, then reliability under high temperature improves, but device cost increases
Solution Approach 1:
The patent extracts the through-hole from the flow path design by using absolute pressure sensors positioned separately. The differential pressure measurement is achieved through calculation rather than physical connection, eliminating the need for heat-resistant through-hole components and reducing device cost while maintaining reliability.
3Ease of operation
If a through-hole is provided in the flow path for pressure sensor connection, then pressure measurement is enabled, but gas leaks occur when temperature becomes extremely high
Solution Approach 1:
The patent uses atmospheric pressure measurement as an intermediary approach. Instead of creating a direct physical connection (through-hole) between the pressure sensor and the gas flow path, the system measures atmospheric pressure outside the flow path and uses it as a reference to calculate gas supply pressure from absolute pressure measurements, thereby eliminating gas leakage risk.
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
Prevents gas ejection during high temperatures and reduces costs by eliminating the need for a through-hole and heat-resistant components, while enhancing reliability and accuracy in pressure determination.
Implementation Method 1
a first absolute pressure sensor disposed inside the flow path to measure an absolute pressure of the gas
Implementation Method 2
a second absolute pressure sensor disposed outside the flow path to measure an absolute pressure of atmospheric pressure
Implementation Method 3
a gas pressure determination unit that measures a change in gas supply pressure from the absolute pressure of the gas and the absolute pressure of the atmospheric pressure measured by the first absolute pressure sensor and the second absolute pressure sensor, respectively
Implementation Method 4
a flow rate measurement unit for measuring a flow rate of the gas flowing through the flow path
Data Source
AI summary
A gas safety device includes: a flow path; a flow rate measurement unit for measuring a flow rate of gas in the flow path; an absolute pressure sensor inside the flow path for measuring an absolute pressure of the gas; an absolute pressure sensor outside the flow path for measuring an absolute pressure of atmospheric pressure; a gas pressure determination unit for measuring a change in gas supply pressure from the absolute pressure of the gas and the absolute pressure of atmospheric pressure measured by the absolute pressure sensor and the absolute pressure sensor, respectively; a shutoff valve for shutting off the flow path; and a control circuit for: (i) controlling the flow rate measurement unit; and (ii) causing the shutoff valve to shut off the flow path when determining an abnormality from the flow rate of the gas or the change in gas supply pressure.