Series Bellows Cryogenic Pumping for High-Pressure Liquid Supply
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Solution Overview
Problem
Conventional liquid supply systems for ultracold liquids, such as liquid nitrogen, face challenges in achieving high discharge pressure over long distances and in topographically varied areas, leading to inefficient pumping and increased costs due to the limitations of centrifugal pumps and positive-displacement bellows circulators, which can buckle under high pressure and suffer from heat leakage.
Innovation Solution
A liquid supply system featuring a vessel with first and second bellows arranged in series, where the bellows are expanded and contracted by a reciprocally moved shaft to create alternating pump chambers, reducing pulsation and internal pressure on the bellows, and an evacuated outer vessel to minimize heat transfer, allowing for improved stability and higher discharge pressure without buckling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a centrifugal pump is used for liquid supply, then the device complexity is low, but the discharge pressure is insufficient for long-distance transport
Solution Approach 1:
The pump is divided into multiple bellows units (first bellows and second bellows) arranged in series, each acting as an independent pumping chamber. This segmentation allows the system to achieve higher discharge pressure through cumulative pressure generation while maintaining relatively simple individual component structures.
Solution Approach 2:
Multiple bellows units are combined in series within a single pump body, merging their pumping actions to achieve high discharge pressure. The first and second bellows work sequentially to progressively increase liquid pressure, enabling long-distance transport capability while keeping the overall device as a single integrated unit.
2Stress or pressure
If high discharge pressure is exerted on a bellows circulator, then the pumping capability is improved, but the bellows may buckle
Solution Approach 1:
The pumping function is segmented across multiple bellows units, so that high discharge pressure is achieved through cumulative effect rather than excessive pressure on a single bellows. Each bellows operates within safe pressure limits while contributing to the overall high-pressure output.
Solution Approach 2:
The bellows are designed to dynamically expand and contract in a controlled manner during the pumping cycle. The first bellows expands while the second contracts, and vice versa, creating a dynamic balance that prevents buckling while maintaining high discharge pressure capability.
3Stress or pressure
If a positive-displacement bellows circulator is used, then the discharge pressure is improved, but heat in-leak occurs from the vacuum insulated vessel
Solution Approach 1:
The bellows pumping mechanism is extracted from the vacuum insulated vessel environment. The pump body containing the bellows is positioned outside the vacuum vessel, with only the necessary inlet and outlet connections penetrating the vacuum boundary. This eliminates heat in-leak through the bellows structure and supporting members.
Solution Approach 2:
A vacuum-tight seal structure acts as an intermediary between the vacuum insulated vessel and the external bellows pump. This mediator allows liquid supply while maintaining vacuum isolation, preventing heat transfer from the external pump components to the ultracold liquid inside the vessel.
4Stress or pressure
If multiple pumps are arranged along the cable, then the discharge pressure is maintained, but the device complexity and cost increase
Solution Approach 1:
Multiple bellows units are merged into a single integrated pump body, combining the functions of what would traditionally require multiple separate pumps. The first and second bellows work together in sequence within one device, achieving the cumulative pressure effect of multiple pumps while reducing overall system complexity and cost.
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 achieves enhanced pumping efficiency with reduced pulsation and increased discharge pressure, allowing for more flexible design and reduced heat leakage, enabling efficient ultracold liquid supply over long distances and varied topographies.
Implementation Method 1
an externally evacuated outer vessel and an internally evacuated inner vessel, the inner vessel being placed in the outer vessel so as to be surrounded by a vacuum space
Data Source
AI summary
A liquid supply system includes first and second bellows 41 and 42 arranged in series in an expanding/contracting direction thereof in a vessel 12 and having first end portions respectively, which are close to each other and fixed to an inner wall of the vessel 12, and also having second end portions respectively, which are distant from each other and movable in the expanding/contracting direction. An inner space of the vessel 12 located outside the first bellows 41 serves as a first pump chamber P1. An inner space of the vessel 12 located outside the second bellows 42 serves as a second pump chamber P2. An inner space of the vessel 12 located inside the first and second bellows 41 and 42 serves as a sealed space R1. A shaft 15 to which the respective second end portions of the first and second bellows 41 and 42 are fixed is reciprocally moved to expand/contract the first and second bellows 41 and 42.