Pressurized Gas Gap Heat Transfer Without Contact Wear
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Solution Overview
Problem
Existing devices with movable units housed in gas-filled spaces between the inner and outer surfaces, where the surfaces are closely spaced to maintain high gas pressure and minimize leakage, face challenges in efficiently dissipating heat without causing wear or contamination due to potential contact during thermal expansion.
Innovation Solution
The restriction surfaces between the housing and the movable unit are configured to maintain a constant distance during thermal expansion, with a thermal center alignment that prevents relative movement, ensuring consistent gas pressure and heat transfer without contact, using a gas with high thermal conductivity like helium in a slit-like space for enhanced heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the distance between the restriction surfaces is minimized to maintain high gas pressure and reduce leakage, then gas sealing performance is improved, but heat transfer efficiency deteriorates due to insufficient thermal contact
Solution Approach 1:
The patent changes the geometric parameters of the restriction surfaces by introducing a specific orientation angle (α) relative to the thermal expansion direction. This angular parameter allows the surfaces to maintain optimal spacing for heat transfer while the thermal expansion occurs primarily in the direction perpendicular to the surfaces, preserving gas sealing performance.
Solution Approach 2:
The restriction surfaces are configured asymmetrically with respect to the thermal expansion axes of the housing and movable unit. By orienting the surfaces at an angle rather than parallel to the expansion direction, the design creates an asymmetric geometry that decouples the thermal expansion movement from the gap distance, allowing independent optimization of sealing and heat transfer.
2Temperature
If the distance between the movable unit and housing is reduced to improve heat transfer, then thermal conductivity is enhanced, but the risk of contact and wear increases during thermal expansion
Solution Approach 1:
The patent optimizes the spacing parameter by configuring the restriction surfaces at a specific angle to the thermal expansion direction. This angular configuration allows the gap to be minimized for heat transfer while the thermal expansion occurs in a direction that does not reduce the gap further, preventing contact and wear.
Solution Approach 2:
The angled restriction surface configuration acts as a geometric counterbalance to thermal expansion forces. By orienting the surfaces at an angle, the design compensates for the tendency of thermal expansion to close the gap, maintaining a consistent spacing that prevents contact while allowing efficient heat transfer.
3Ease of manufacture
If conventional restriction surfaces are used, then manufacturing is simplified, but thermal expansion causes varying distances that reduce heat transfer efficiency
Solution Approach 1:
The patent introduces a specific angular parameter (α) as a design variable that can be optimized for heat transfer performance. By treating the orientation angle as a controllable parameter, the design achieves improved thermal contact while maintaining manufacturing feasibility through standard machining operations at defined angles.
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 allows for effective heat transfer from the movable unit to the housing without wear or contamination, maintaining the service life of the bearings and ensuring minimal leakage, while maintaining high gas pressure within the space.
Implementation Method 1
Due to the pressurized gas in the space between the housing and the movable unit, better heat transfer occurs than if a lower pressure gas or no gas is present in the space
Implementation Method 2
At thermal expansion of the housing and the movable unit the distance between the restriction surfaces remains the same
Data Source
Figure 1
AI summary
A device 31 is provided with a housing 33 and a movable unit 35 present therein. The space 7 between the inside 33b of the housing and the outside 35b of the movable unit is filled with gas having a pressure higher than the ambient pressure. By increasing the gas pressure in the space, more heat is transferred from the movable unit to the housing via the gas. In order to maintain this higher gas pressure in this space without the movable unit coming into contact with the housing, which entails friction and thus undesirable heat development, a contactless restriction 37 is arranged between the movable unit 35 and the housing 33. This restriction 37 is formed by two closely spaced restriction surfaces 33c and 35c of the inside of the housing and the outside of the movable unit.