A comprehensive review of key technologies for the development of oil-free single screw compressors

As industries such as food, pharmaceuticals, electronics, and chemicals advance towards high-end refinement, there is an increasing demand for pure, oil-free compressed gas. This demand is driven by the need to ensure product quality, adhere to precision technology requirements, and strictly comply with production safety standards. Consequently, the trend towards using oil-free compressor is rapidly growing across various sectors. However, the majority of compressors labeled as "oil-free" are not entirely devoid of oil, as they still require bearing lubrication. Consequently, the advancement of water-lubricated oil-free compressors has emerged as a significant research focus for the future. Despite the evident performance benefits of oil-free single-screw compressors (SSCs), there is a scarcity of publicly available studies on this topic, and no comprehensive overview exists regarding the key technologies involved in the development of water-lubricated oil-free SSCs. This work aims to address this gap by synthesizing the limited public reports on the development of water-lubricated oilfree SSC technology. Additionally, it examines other relevant technologies that can inform the development of such compressors. The work provides a systematic overview of the basic performance modeling and prediction of water-lubricated oil-free SSCs, as well as the development of their key components. Finally, it offers forwardlooking perspectives on the future development of this technology.