Single-Pump Helium Circulation for Dilution Refrigerator Cooling
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Solution Overview
Problem
Existing helium gas handling systems for dilution refrigerators are limited by the need for multiple turbopumps and backing pumps, which are costly, large, and complex, posing challenges in assembly, testing, and installation, and do not scale well for increased cooling demands.
Innovation Solution
A single primary pump unit, utilizing Roots pumps, integrates helium vapor capture, circulation, and condensation, eliminating the need for separate turbopumps and compressors, and allowing for compact, efficient helium flow management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple turbopumps and backing pumps are used to improve helium circulation performance, then the cooling performance is improved, but the system size, cost, and complexity increase considerably
Solution Approach 1:
The patent combines multiple separate pump functions (turbopump for helium vapor removal, backing pump for maintaining vacuum, and compressor for helium condensation) into a single integrated pump unit. This unified design maintains the necessary cooling performance while significantly reducing system complexity, size, and cost compared to using multiple separate pump components.
Solution Approach 2:
The single pump unit is designed to perform multiple functions simultaneously: it acts as a turbopump for helium vapor removal, a backing pump for vacuum maintenance, and provides compression for helium condensation. This multi-functional design eliminates the need for separate specialized pumps while maintaining optimal performance for each function.
2Power
If additional turbopumps are added to increase cooling power, then the cooling capacity is improved, but the cost, weight, and installation difficulty increase
Solution Approach 1:
Instead of adding multiple separate turbopumps to increase cooling power, the patent integrates all pumping and compression functions into a single unified pump unit. This design achieves the required cooling power through optimized internal architecture and multi-functionality, thereby avoiding the increased weight and installation complexity that would result from adding multiple separate pump components.
3Productivity
If the size of the backing pump is increased to improve helium circulation, then the flow rate is improved, but the system size and cost increase
Solution Approach 1:
The patent integrates the backing pump function within a compact unified pump unit that also performs turbopumping and compression functions. Through optimized internal architecture and efficient space utilization, the single pump unit achieves high helium flow rates without requiring a large physical volume, thereby avoiding the increased system size and cost associated with oversized separate backing pumps.
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 solution enables higher helium flow rates and improved cooling performance, reducing system size and cost while simplifying assembly and maintenance, and supports both large and small cryostat systems with adjustable pump power.
Implementation Method 1
causing the helium vapor to be condensed for the helium input flow at the dilution refrigerator by providing the pressure for condensing the helium vapor
Implementation Method 2
maintaining a helium output flow comprising helium vapor from the dilution refrigerator and a helium input flow into the dilution refrigerator
Data Source
Figure 1
Figure 2
AI summary
Disclosed is a gas handling system (GHS) for a dilution refrigerator, the GHS comprising a primary pump unit arranged for maintaining a helium output flow comprising helium vapor from the dilution refrigerator and a helium input flow into the dilution refrigerator for maintaining a cooled operating temperature of the dilution refrigerator. The primary pump unit is arranged for facilitating initiating the helium input flow and the helium output flow for cooling the dilution refrigerator by both capturing the helium vapor from the dilution refrigerator and causing the helium vapor to be condensed for the helium input flow at the dilution refrigerator.