Split pulse tube connecting line
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Solution Overview
Problem
Current GM type pulse tube refrigerators with a split Pressure Wave Generator (PWG) and cold head suffer from significant losses and vibration transmission due to the connecting line, particularly at cryogenic temperatures, which affects cooling efficiency and vibration isolation.
Innovation Solution
The connecting line is optimized by using a metal hose with reduced internal void volume through fewer corrugations, closer spacing of outer convolutions, and filling inner volumes with elastomers, along with vibration-absorbing coatings and elastomer seals to prevent metal-to-metal contact, allowing for flexible bending and improved vibration isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a connecting line is used to separate the valve mechanism from the cold head, then vibration isolation is improved, but losses in the connecting line increase
Solution Approach 1:
The patent employs a flexible connecting line with corrugated structure that allows vibration isolation through flexibility while minimizing internal void volume to reduce cooling losses. The corrugated design provides mechanical compliance for vibration damping while the optimized geometry reduces thermal and fluid dynamic losses.
Solution Approach 2:
The patent extracts and eliminates the harmful internal void volumes from the connecting line structure by reducing corrugation depth and optimizing the profile, thereby removing the source of cooling losses while preserving the external flexible structure needed for vibration isolation.
2Adaptability or versatility
If corrugated hose is used for the connecting line, then flexibility and vibration isolation are improved, but internal void volume increases causing losses
Solution Approach 1:
The patent applies different corrugation characteristics to different sections of the connecting line, with tighter corrugations in regions requiring flexibility and smoother transitions in regions where pressure drop must be minimized, optimizing both flexibility and efficiency locally.
Solution Approach 2:
The patent optimizes the corrugation parameters including depth, pitch, and cross-sectional profile to reduce internal void volume while maintaining flexibility. The connecting line is designed with controlled geometric parameters that balance mechanical compliance with fluid dynamic efficiency.
3Ease of manufacture
If the connecting line is fixed in position, then installation simplicity is improved, but vibration transmission increases
Solution Approach 1:
The patent transitions from a fixed rigid connecting line to a dynamic flexible structure that can adapt its configuration. The flexible corrugated design allows the connecting line to move and absorb vibrations while maintaining a relatively simple installed configuration, combining ease of installation with vibration isolation.
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
This configuration reduces losses and vibration transmission, enhancing cooling efficiency and maintaining vibration isolation while allowing for convenient mounting, thus improving the performance of GM type pulse tube refrigerators at cryogenic temperatures.
Implementation Method 1
filling inner volumes with elastomers, along with vibration-absorbing coatings
Implementation Method 2
filling inner volumes with elastomers
Implementation Method 3
elastomer seals to prevent metal-to-metal contact
Implementation Method 4
vibration-absorbing coatings
Data Source
AI summary
Losses in the connecting line between the Pressure Wave Generator and the cold head of a GM type pulse tube refrigerator, are reduced while maintaining or improving upon the desirable features of a standard corrugated hose connecting line including vibration isolation, separation distance, and mounting convenience. The basic means are to reduce the internal void volume of the convolutions in a corrugated hose in combination with reducing the number of corrugations, adding fillers to the void volumes, and vibration absorbing coatings.