Oil separator, filter element, and compressor for cryocooler
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Solution Overview
Problem
The existing oil separators in cryocooler compressors allow a significant outflow of oil, which leads to premature adsorbent replacement, increased operating costs, and potential deterioration of the expander and reduction in cooling capacity due to oil solidification at low temperatures.
Innovation Solution
An oil separator design incorporating a filter element with a tubular inner filter member, an outer filter layer, and a wire-like or band-like filter retaining member that reduces oil outflow by effectively separating oil from refrigerant gas and preventing its re-mixing, featuring a large refrigerant gas outlet surface area to minimize pressure loss and oil re-scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large adsorber with a large amount of adsorbent is employed to reduce oil outflow, then the frequency of replacement of the adsorbent can be reduced, but this causes an increase in the size of the compressor
Solution Approach 1:
The oil separator is divided into multiple functional zones: an inner cavity for initial separation, an outer cavity for further separation, and multiple filter layers (inner filter member, outer filter layer) with different pore sizes arranged in sequence. This segmentation allows progressive oil removal, achieving high separation efficiency without requiring a large adsorber
Solution Approach 2:
Different regions of the oil separator are designed with different properties: the inner filter member has smaller pore sizes for fine filtration, while the outer filter layer has larger pore sizes for coarse filtration. The refrigerant gas flows through zones with progressively different filtration characteristics, optimizing separation at each local region without uniformly increasing the entire device size
2Loss of substance
If the oil is not removed by the adsorber, then the operating cost is reduced, but the oil flows into an expander together with the refrigerant gas and may be solidified at a low-temperature part, causing deterioration of the expander and reduction in cooling capacity
Solution Approach 1:
The oil separator performs preliminary oil removal before the refrigerant gas enters the expander. By separating oil in advance through the filter elements and collecting it in the outer cavity, the system prevents oil from reaching the expander and causing solidification, thereby protecting expander reliability without incurring high operating costs for adsorbent replacement
3Ease of manufacture
If a simple filter structure is used to reduce manufacturing cost, then the manufacturing precision may be insufficient, but the patent employs a multi-layer filter structure with specific pore size requirements to achieve high separation efficiency
Solution Approach 1:
The patent utilizes porous filter materials with specifically controlled pore sizes: the inner filter member has pore sizes of 0.01 to 0.1 mm for fine filtration, while the outer filter layer has pore sizes of 0.1 to 1.0 mm for coarse filtration. This use of porous materials with graded pore structures achieves high separation efficiency without requiring complex manufacturing processes, balancing manufacturing ease with separation performance
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 reduces oil outflow from the oil separator, extending the life of the adsorbent, lowering replacement frequencies, reducing compressor size, and maintaining cooling capacity by minimizing oil-induced expander deterioration and re-mixing.
Implementation Method 1
a filter element that is disposed in the oil separator container, defines an outer cavity between the oil separator container and itself, includes an inner cavity into which refrigerant gas is introduced, and separates oil from the refrigerant gas flowing to the outer cavity from the inner cavity
Implementation Method 2
This oil is adsorbed by the adsorber and is removed from the refrigerant gas
Data Source
Figure 1
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AI summary
The outflow of oil from an oil separator (20) is reduced. An oil separator (20) includes: an oil separator container (44) ; and a filter element (46) that is disposed in the oil separator container (44), defines an outer cavity (48) between the oil separator container (44) and itself, includes an inner cavity (50) into which refrigerant gas is introduced, and separates oil from the refrigerant gas flowing to the outer cavity (48) from the inner cavity (50). The filter element (46) includes a tubular inner filter member (68) that surrounds the inner cavity (50), and an outer filter layer (72) that includes a refrigerant gas outlet surface (74) exposed to the outer cavity (48) and is disposed outside the inner filter member (68). A wire-like or band-like filter retaining member (60) that is in contact with the outer filter layer (72) from the outside may be provided. The refrigerant gas outlet surface (74) may occupy at least 80% of the surface area of the outer filter layer (72).