Gas Delivery Line Pressure Triggering for Early Backflow Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current natural gas line control systems face issues with backflow due to upstream pressure drops, which are costly to address with check valves and require frequent maintenance, and fail to prevent reverse flow effectively.
Innovation Solution
A monitor control valve system with integrated upstream pressure sensing and a trigger valve to prevent flow reversal by closing the control valve when upstream pressure drops below a setpoint, eliminating the need for separate check valves.
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 device complexity 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. The monitor valve, which normally regulates downstream pressure, is enhanced to also detect upstream pressure drops and close automatically to prevent backflow. This merging eliminates the need for a separate check valve while maintaining both pressure regulation and backflow prevention functions in a single integrated system.
Solution Approach 2:
The monitor control valve is designed to perform multiple functions: normal downstream pressure regulation and upstream backflow prevention. By equipping the monitor valve with pressure sensing capabilities and automated control logic, it becomes a multi-functional device that can respond to both over-pressure conditions (normal function) and under-pressure conditions (backflow prevention), replacing what previously required separate specialized valves.
2Reliability
If a check valve is installed to prevent backflow, then backflow prevention is improved, but maintenance cost and operational burden increase
Solution Approach 1:
The enhanced monitor control valve system operates autonomously by continuously monitoring upstream pressure through the pressure sensor. When a pressure drop indicating potential backflow is detected, the system automatically closes the valve without requiring manual intervention. This self-monitoring and self-actuating capability eliminates the need for annual maintenance and certification that check valves require, as the system serves itself by detecting and responding to backflow conditions in real-time.
3Reliability
If a check valve is used for backflow prevention, then reverse flow blocking is improved, but response time to pressure drop increases
Solution Approach 1:
The system employs continuous feedback through the pressure sensor that monitors upstream pressure in real-time. When the sensor detects a pressure drop below a predetermined threshold, it immediately signals the control logic to close the monitor valve. This closed-loop feedback mechanism ensures the valve responds instantly to pressure changes, whereas a check valve can only close after pressure equalization occurs, which takes time after a rupture.
Solution Approach 2:
The pressure sensor is set to trigger valve closure at a predetermined pressure threshold that is higher than the downstream pressure. This preliminary action allows the valve to close before complete pressure equalization between upstream and downstream sides occurs. By acting in advance at an earlier stage of pressure drop, the system prevents backflow from establishing, rather than responding after equalization has already happened.
4Reliability
If a check valve is installed upstream, then backflow prevention is improved, but gas loss before valve closure increases
Solution Approach 1:
The pressure sensor triggers the monitor valve to close when upstream pressure drops below a predetermined setpoint that is maintained above downstream pressure. This preliminary closure action occurs before pressure equalization can happen, thereby preventing the window of opportunity for backflow to occur. By acting in advance at an earlier pressure threshold, the system minimizes the volume of gas that can escape to the atmosphere during a rupture event.
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 system effectively prevents backflow earlier than traditional check valves, reducing gas loss and maintenance costs while ensuring safety and reliable pressure regulation.
Implementation Method 1
an upstream pressure sensor that triggers the trigger valve to close the control valve in the event of an upstream pressure drop
Implementation Method 2
When the pressure at P1 falls below pressure at P2, a reverse flow scenario is created
Data Source
AI summary
A method for preventing flow reversal due to an upstream pressure drop in a natural gas supply line. The method, using a unique system configuration, includes 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.