Monitor Control Valve Closure for Natural Gas Backflow Prevention
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Solution Overview
Problem
Current natural gas line control systems fail to prevent backflow effectively, especially during significant upstream pressure drops, requiring costly and maintenance-intensive check valves, and lack a failsafe mechanism to address both over-pressure and reverse flow scenarios.
Innovation Solution
A control system incorporating an upstream pressure sensor and trigger valve to automatically close the control valve when upstream pressure falls below a predetermined threshold, eliminating the need for separate check valves and ensuring rapid flow reversal prevention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a check valve is installed upstream of the control valve to prevent backflow, then backflow prevention capability is improved, but installation cost and maintenance cost increase
Solution Approach 1:
The patent combines the backflow prevention function with the existing monitor control valve by adding a pressure sensor and control logic. Instead of installing a separate check valve, the system uses the monitor valve's actuator and control system to detect upstream pressure drops and close the valve automatically, merging multiple functions into a single integrated system.
Solution Approach 2:
The patent replaces the mechanical check valve system with a controlled valve system that uses electronic pressure sensing and control logic. The pressure sensor continuously monitors upstream pressure, and when a drop is detected, the control system actuates the monitor valve to close, substituting passive mechanical backflow prevention with active electronic control.
2Reliability
If a check valve is used to prevent backflow, then backflow prevention is achieved, but the response time is delayed until pressure equalization occurs
Solution Approach 1:
The patent implements a feedback control system where a pressure sensor continuously monitors upstream pressure and provides real-time data to the control logic. When the sensor detects a pressure drop below the setpoint, the control system immediately responds by actuating the monitor valve to close, creating a closed-loop feedback mechanism that enables rapid detection and response to backflow conditions.
Solution Approach 2:
The system performs preliminary action by continuously monitoring upstream pressure before backflow actually occurs. The pressure sensor detects pressure drops in real-time, and the control system closes the monitor valve proactively before reverse flow can establish, preventing backflow rather than merely responding to it after pressure equalization.
3Loss of substance
If a check valve is installed to prevent reverse flow, then product loss is reduced, but the system complexity and cost increase
Solution Approach 1:
The patent makes the monitor control valve multi-functional by enabling it to perform both its original over-pressure protection function and the new backflow prevention function. The same valve, actuator, and control system handle both scenarios, eliminating the need for separate dedicated components for each function and reducing overall system complexity.
Solution Approach 2:
The patent merges the backflow prevention function with the existing monitor control valve system. By integrating pressure sensing, control logic, and valve actuation into a single unified system, the patent reduces device complexity compared to installing separate check valves, while effectively preventing gas loss through either over-pressure or backflow scenarios.
4Object-affected harmful factors
If traditional check valves are used for backflow prevention, then safety is improved, but annual maintenance and certification requirements increase operational burden
Solution Approach 1:
The patent implements a self-monitoring system where the pressure sensor continuously tracks upstream pressure and automatically triggers valve closure when backflow conditions are detected. The system serves itself by using its own sensing and control capabilities to prevent backflow, eliminating the need for external maintenance and certification of separate check valves while maintaining continuous safety monitoring.
Data Source
AI summary
A gas supply line control system and method for preventing flow reversal due to an upstream pressure drop in a natural gas supply line, the system and method include setting a threshold low pressure for the upstream gas flow, continually sensing the upstream pressure, activating a trigger valve when the upstream pressure falls below the threshold low pressure, and closing a control valve in response to the trigger valve to prevent reversal of flow in the gas supply line.