Fluid Machine Casing Seal to Prevent Refrigerant Convection
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Solution Overview
Problem
Fluid machines with a single casing for compression and expansion mechanisms face performance degradation and decreased power recovery due to refrigerant convection between the expansion and compression mechanisms, despite the use of heat insulators, as the existing solutions fail to prevent heat exchange through mass transfer and thermal expansion damage.
Innovation Solution
A fluid machine design that incorporates an elastically deformable seal element, such as an O-ring or flange, to seal the clearance between the heat insulator and the casing, along with a communicating channel to reduce pressure differences, effectively preventing refrigerant convection and maintaining the temperature and pressure differences between the expansion and compression spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a heat insulator is attached to the expansion mechanism to prevent heat loss, then the power recovery effect is improved, but refrigerant convection occurs between the expansion and compression mechanisms through the clearance, causing performance degradation
Solution Approach 1:
A seal member (elastically deformable sealing element) is introduced as an intermediary component between the heat insulator and the casing to prevent refrigerant convection through the clearance, while the heat insulator itself remains in place to maintain thermal isolation and power recovery effect
Solution Approach 2:
The seal member is made of elastically deformable material that forms a flexible sealing barrier, allowing it to conform to the clearance space and effectively block refrigerant convection paths without rigid structural constraints
2Loss of energy
If a heat insulator is attached to the expansion mechanism to reduce thermal conduction, then heat loss is reduced, but assembly becomes difficult and thermal expansion damage may occur
Solution Approach 1:
The heat insulator is designed with a flexible, elastically deformable seal member that can be easily installed by elastic deformation, allowing simple assembly while maintaining effective thermal insulation through the clearance
Solution Approach 2:
The seal member utilizes elastic deformation dynamics, allowing the heat insulator to be installed by temporary deformation and then maintaining a sealed position through elastic recovery, simplifying the assembly process
3Loss of energy
If a heat insulator is attached to the expansion mechanism to prevent thermal conduction, then heat loss is reduced, but the heat insulator may be damaged by thermal expansion differences
Solution Approach 1:
The elastically deformable seal member acts as a buffer that absorbs thermal expansion differences between the heat insulator and casing, preventing stress concentration and potential damage to the heat insulator while maintaining sealing effectiveness
Solution Approach 2:
The elastic deformability of the seal member provides beforehand cushioning against thermal expansion forces, preventing damage to the heat insulator before it can occur by allowing controlled deformation under thermal stress
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 prevents refrigerant convection and heat exchange due to mass transfer, thereby enhancing the performance and power recovery of the fluid machine while ensuring ease of assembly and preventing thermal expansion damage to the heat insulator.
Implementation Method 1
a heat insulator (90) disposed in the internal space of the casing (31) and passed through by the rotary shaft (40), the heat insulator (90) partitioning the internal space of the casing (31) into a first space (48) in which the expansion mechanism (60) is placed and a second space (49) in which the compression mechanism (50) is placed
Implementation Method 2
an elastically deformable seal means (92, 94) sealing a clearance between the outer periphery of the heat insulator (90) and the inner periphery of the casing (31)... prevents refrigerant convection between the first space around the expansion mechanism and the second space around the compression mechanism
Implementation Method 3
an elastically deformable seal means (92, 94) sealing a clearance between the outer periphery of the heat insulator (90) and the inner periphery of the casing (31)... prevention of thermal expansion damage to the heat insulator
Data Source
AI summary
A fluid machine includes a casing, a compression mechanism for compressing refrigerant, an expansion mechanism for expanding refrigerant, and a rotary shaft connecting the compression mechanism and the expansion mechanism. The compression mechanism, the expansion mechanism and the rotary shaft are disposed in the casing. A heat insulator partitions an internal space of the casing into a first space with the expansion mechanism disposed therein and a second space with the compression mechanism disposed therein. The rotary shaft passes through the heat insulator. An elastically deformable seal element seals a clearance between an outer periphery of the heat insulator and an inner periphery of the casing.