Submersible Pump Column Door for Zero-Purge Cryogenic Handling
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Solution Overview
Problem
The existing methods for installing and removing submersible pumps in liquefied gas storage tanks require large amounts of expensive purge gas to prevent boil-off gas release and expose workers to dangerous conditions, posing safety and cost challenges.
Innovation Solution
A pump installation apparatus with an actuator-driven door, suspension and power cables, and a crane system that allows for remote operation within an enclosed working space, minimizing purge gas use and ensuring worker safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the upper opening of the pump column is left open to allow pump installation and removal, then worker accessibility is improved, but boil-off gas is released into the atmosphere and air may enter the pump column
Solution Approach 1:
A door is introduced as an intermediary component between the pump column interior and the external environment. The door can be opened to allow pump installation and removal, then closed to prevent boil-off gas release and air contamination. This intermediary structure enables both worker accessibility and environmental protection without compromising either function.
2Reliability
If purge gas is continuously supplied to prevent air entry and boil-off gas release during pump installation and removal, then safety is improved, but the cost increases due to consumption of expensive He gas
Solution Approach 1:
Instead of continuous purge gas supply, the system uses periodic action: the door is closed during critical phases (when the pump column is open for maintenance operations), and purge gas is supplied only during these specific periods. This periodic approach maintains safety during vulnerable operations while minimizing overall gas consumption compared to continuous supply.
Solution Approach 2:
The pump column interior is maintained as an inert environment by closing the door and supplying purge gas only when necessary. This creates a controlled atmosphere that prevents air contamination and boil-off gas release during maintenance operations, while the inert environment is maintained only during critical phases rather than continuously, reducing gas consumption.
3Ease of operation
If the pump is suspended by a cable that contacts liquefied gas, then the pump can be lowered into the pump column, but the cable becomes extremely cold and dangerous to handle
Solution Approach 1:
The harmful effect of extreme cold on the cable is extracted and isolated. The cable that contacts liquefied gas and becomes extremely cold is separated from the sections that workers must handle. The door mechanism allows the cold cable to remain inside the pump column while workers operate from the outside, effectively taking out the thermal hazard from the operational zone.
Solution Approach 2:
The door acts as an intermediary thermal barrier. It allows the suspension cable to pass through while preventing direct thermal contact between the cold cable and the external environment where workers handle it. The door isolates the extreme cold zone (inside the pump column) from the safe handling zone (outside), protecting workers from thermal hazards.
Data Source
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AI summary
The pump installation apparatus includes a working chamber (1) forming a closed working space (15), an actuator-driven door (12) covering an upper opening (3a) of a pump column (3), a suspension cable (23) for suspending a submersible pump (2) in the pump column (3), a power cable (36) for supplying electric power to the submersible pump (2), and a crane (40) for raising and lowering the suspension cable (23) and the power cable (36). The upper opening (3a) of the pump column (3), the actuator-driven door (12), and the crane (40) are located in the working space (15).