Multistage Oil Separator for Cryogenic Helium Purity

The patent divides the filtration function into multiple stages by arranging several filter elements (first filter element, second filter element, third filter element) in series within the housing. Each filter element handles a portion of the oil separation task, with the first filter element capturing larger oil droplets, the second filter element refining the separation, and the third filter element providing final polishing. This segmentation approach achieves reliable oil separation while keeping each individual filter element relatively simple in design.

The patent merges multiple filter elements into a single integrated housing structure rather than using separate housings for each filter element. The housing contains all filter elements (first, second, and third filter elements) arranged in cascade, sharing common inlet and outlet passages. This merging approach reduces the total number of housing components, simplifies manufacturing, and lowers costs while maintaining the multi-stage filtration capability needed for effective oil separation.

The patent implements oil passages that utilize gravity to automatically return separated oil to the compressor without requiring external pumps or complex mechanical systems. The housing is oriented and configured so that oil, after being separated by the filter elements, flows down through gravity into collection areas and then through oil passages back to the compressor. This self-service approach leverages the natural gravitational field to achieve efficient oil return while keeping the device structure relatively simple.