Cryocooler Flexible Hose Braid Design to Reduce Gas Flow Noise
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Solution Overview
Problem
The existing flexible hoses for cryocoolers, designed to reduce noise by smoothing the inner surface with a flexible pipe, face issues with noise deterioration due to braid design and working gas pressure, and also incur higher manufacturing costs and reliability concerns due to the additional flexible pipe.
Innovation Solution
A cryocooler system with a flexible hose that includes a conduit with a corrugated inner surface and an inter-corrugation gap of 1 mm or less, and a braid externally mounted on the conduit with a braided wire woven into a tubular shape, configured to maintain a tensile stress of 85 N/mm² or less on the braided wire at nominal pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a flexible pipe is mounted on the inner surface of the bellows-shaped flexible hose to smooth the inner surface, then noise caused by gas flow is reduced, but manufacturing cost increases and long-term reliability deteriorates due to additional parts and abrasion
Solution Approach 1:
The invention removes the flexible pipe component from the flexible hose structure, retaining only the bellows-shaped conduit with optimized geometric parameters. This extraction eliminates the need for additional parts while maintaining noise reduction functionality through the corrugation design itself
Solution Approach 2:
The invention changes the geometric parameters of the bellows-shaped conduit, specifically setting the inter-corrugation gap to 1 mm or less and optimizing the corrugation depth and width ratios. These parameter changes enable the conduit's own structure to smooth gas flow and reduce noise without requiring additional components
2Object-generated harmful factors
If a flexible pipe is mounted on the inner surface of the bellows-shaped flexible hose, then noise caused by gas flow is reduced, but manufacturing cost increases due to additional parts
Solution Approach 1:
The invention removes the flexible pipe component from the flexible hose structure, retaining only the bellows-shaped conduit with optimized geometric parameters. This extraction eliminates the need for additional parts while maintaining noise reduction functionality through the corrugation design itself
Solution Approach 2:
The bellows-shaped conduit is designed to perform multiple functions: it provides flexibility for movement, structural support, and noise reduction through its optimized corrugation geometry. This multi-functionality eliminates the need for separate flexible pipe components
3Strength
If a braid with high tensile stress is used to cover the conduit, then structural strength is improved, but noise level deteriorates
Solution Approach 1:
The invention optimizes the tensile stress parameter of the braid to be 85 N/mm² or less, finding the optimal balance between providing sufficient structural strength and minimizing noise generation from the braid structure during gas flow operations
Data Source
Figure 1
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Figure 3A~3C
AI summary
The task is to reduce noise generated from a flexible hose (63, 64, 70) during an operation of a cryocooler (10). A cryocooler (10) includes a compressor (12), a cold head (14), and a first flexible hose (63) that connects the compressor (12) to the cold head (14). The first flexible hose (63) includes a conduit (72) through which a working gas of the cryocooler (10) flows and a braid (74) externally mounted on the conduit (72). The braid (74) includes a braided wire (76) woven into a tubular shape to cover the conduit (72), and is configured such that a tensile stress that acts on the braided wire (76) when the working gas flows through the conduit (72) at a nominal pressure is 85 N/mm2 or less.