Venturi Purging of an Isolated Subsystem to Prevent Explosive Gas Mix
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Solution Overview
Problem
Existing methods for preparing systems for maintenance operations involving flammable fluids under super-atmospheric pressure pose a risk of explosion due to the potential mixture of flammable gas and oxygen, especially when ambient air enters the system.
Innovation Solution
The method involves using a venturi-pump driven by an anoxic gas to create a sub-atmospheric pressure in the second subsystem, which removes flammable gas through a bleed conduit while preventing oxygen ingress, thus reducing the risk of explosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sub-atmospheric pressure is applied to remove flammable gas from the second subsystem, then the effectiveness of gas removal is improved, but the risk of oxygen ingress and explosion hazard increases
Solution Approach 1:
A venturi pump is introduced as an intermediary device to remove flammable gas from the second subsystem. The venturi pump creates sub-atmospheric pressure through its operation, enabling effective gas removal while controlling the pressure differential to prevent excessive oxygen ingress that would create explosion hazards
Solution Approach 2:
The pressure parameter in the second subsystem is changed to sub-atmospheric levels during the gas removal phase, then restored to atmospheric pressure before maintenance begins. This dynamic parameter change allows effective gas removal while ensuring safety conditions are met for maintenance personnel
2Object-generated harmful factors
If sealing blocks are used to block gas flow, then the prevention of gas leakage is improved, but the ability to perform maintenance on the third subsystem is hindered
Solution Approach 1:
The system is segmented into multiple subsystems (first, second, and third subsystems) separated by sealing blocks. This segmentation allows the third subsystem to be isolated for maintenance while the first subsystem continues to contain flammable fluid under pressure, enabling maintenance access without compromising gas leakage prevention
Solution Approach 2:
The second subsystem acts as an intermediary zone between the pressurized first subsystem and the maintenance area (third subsystem). By controlling the pressure and composition of gas in this intermediate zone, the system prevents flammable gas from reaching the maintenance area while still allowing the maintenance to proceed
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
This approach allows for safer maintenance operations by ensuring that the concentrations of oxygen and flammable gas in the exhaust mixture are never within the flammable range, thereby minimizing the risk of explosions and ensuring personnel safety.
Implementation Method 1
The method involves using a venturi-pump driven by an anoxic gas to create a sub-atmospheric pressure in the second subsystem, which removes flammable gas through a bleed conduit
Data Source
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AI summary
A method of preparing a system for a maintenance operation, said system comprising a first subsystem, a second subsystem, a third subsystem separated by sealing blocks. To reduce the hazard risk, the step of removing gas from the second subsystem via a bleed conduit comprises applying the sub-atmospheric pressure using a venturi-pump into which an anoxic gas to drive said venturi-pump is introduced to mix with and remove gas from the second subsystem, said venturi-pump having a maximum venturi ratio Mvr.