Gas Control Valve With Inverse Pressure Sensing for Fail-Safe Control
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Solution Overview
Problem
Existing gas control valves and units are not designed to be fail-safe, leading to high costs due to the need for specialized software, hardware, and certifications, and lack effective plausibility checks for differential pressure measurements.
Innovation Solution
A gas control unit with two sensor modules that measure mutually inverse differential pressures, transmitting these values to an external receiver for plausibility checking, ensuring fail-safe operation by comparing signed pressure values with setpoint or threshold values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas control valves are designed to be fail-safe with specialized software, additional hardware, and duplicate components, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses a single differential pressure sensor whose signal is copied and processed through two different evaluation paths: a first evaluation unit for normal operation and a second evaluation unit for fail-safe monitoring. This copying approach provides redundant safety functionality without duplicating the entire sensor system, thus improving reliability while controlling complexity.
Solution Approach 2:
The single differential pressure sensor serves multiple functions: it provides pressure measurement for normal gas flow control through the first evaluation unit, and simultaneously provides safety monitoring through the second evaluation unit. This multi-functionality eliminates the need for separate sensors for each purpose, reducing device complexity while maintaining fail-safe operation.
2Device complexity
If a single differential pressure sensor is used for pressure control, then device complexity is reduced, but reliability and plausibility checking capability deteriorate
Solution Approach 1:
The evaluation process is segmented into two independent evaluation units: a first evaluation unit for normal pressure control operations and a second evaluation unit specifically for plausibility checking and fail-safe monitoring. This segmentation allows the system to maintain simplicity with a single sensor while achieving reliable plausibility verification through dedicated evaluation logic.
Solution Approach 2:
The second evaluation unit continuously monitors the differential pressure signal and provides feedback on its plausibility by comparing it against expected operational ranges and patterns. This feedback mechanism enables reliability checking without requiring additional sensors, as the same sensor signal is evaluated against multiple criteria by the second evaluation unit.
3Device complexity
If fail-safe control is implemented without plausibility checks, then device complexity is reduced, but measurement accuracy and error detection capability worsen
Solution Approach 1:
The second evaluation unit performs preliminary plausibility checks on the differential pressure signal before it is used for critical safety decisions. By evaluating the signal's合理性 in advance through the second evaluation unit, the system ensures measurement accuracy without adding complex post-detection verification systems, thus maintaining simplicity while improving measurement precision.
Data Source
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AI summary
The invention relates to a gas control unit (10) for the fail-safe control of a gas, in particular in a gas heater (1) or a gas burner, wherein the gas control unit (10) has a communication interface (15), a first sensor assembly (11) and a second sensor assembly (12), wherein the first sensor assembly (11) is designed to acquire measured values from which a signed first differential pressure (p11) between a process pressure (p1) of the gas and a reference pressure (p0) can be determined, and wherein the second sensor assembly (12) is designed to acquire measured values from which a signed second differential pressure (p12) between the reference pressure (p0) and the process pressure (p1) can be determined, such that the signed first differential pressure (p11) and the signed second differential pressure (p12) are signed, mutually inverse differential pressures (p11, p12).and wherein the communication interface (15) is designed to send the mutually inverse differential pressures (p11, p12) and/or the measured values to an external receiver.,