Submersible Pump Bypass Flow Path to Prevent Impeller Rotation
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Solution Overview
Problem
When performing drying-up, cooling-down, and hot-up operations on submersible pumps used for liquefied gases, the introduction of purge, liquefied, or warming gases can unintentionally rotate the impellers, leading to damage to sliding parts such as bearings, especially when multiple pumps are coupled in series.
Innovation Solution
The implementation of flow-path switching devices that allow gases to bypass the submersible pumps during these operations, using a configuration with pump-side, container-side, and outlet flow passages, and a valve element to control communication between these passages, ensuring gases flow around the impellers when the pumps are not in operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If purge gas is introduced into the suction container to perform drying-up operation, then air is removed from the suction container, but the impeller rotates unintentionally causing damage to sliding parts
Solution Approach 1:
A flow-path switching device is introduced as an intermediary component between the suction container and the pump. This device includes a bypass passage that allows purge gas to flow around the impeller rather than through it. The switching device directs the gas flow along a predetermined path that excludes the impeller, thereby preventing unintended rotation while still achieving the drying-up function of removing air from the suction container.
2Temperature
If liquefied gas is introduced into the suction container to perform cooling-down operation, then the pump is cooled to ultra-low temperature, but the impeller rotates unintentionally causing damage to sliding parts
Solution Approach 1:
The flow-path switching device serves as a mediator that separates the cooling function from the impeller. By providing a bypass passage, it allows liquefied gas to flow through the suction container and cool the pump body without passing through the impeller. This prevents the impeller from rotating due to gas flow while still achieving the necessary ultra-low temperature cooling for proper pump operation.
3Reliability
If purge gas flows through multiple pump apparatuses coupled in series, then drying-up operation is performed on all pumps, but impellers of non-operating pumps rotate causing damage to sliding parts
Solution Approach 1:
The flow-path switching device segments the gas flow path for each pump apparatus in the series configuration. Each pump has its own switching device with a bypass passage, allowing independent control of gas flow through each pump. This segmentation ensures that when purge gas flows through multiple pumps, only the operating pump receives gas through its impeller, while non-operating pumps have their impellers protected by closed bypass passages, preventing rotation damage in each segment of the system.
Data Source
AI summary
The drying-up method includes introducing a purge gas into a suction container of a pump apparatus, passing the purge gas through a flow-path switching device in the suction container while the purge gas bypasses a submersible pump in the suction container, introducing the purge gas that has passed through the flow-path switching device into a suction container of a pump apparatus, and passing the purge gas through the flow-path switching device in the suction container while the purge gas bypasses a submersible pump in the suction container.