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A pneumatic slip ring is a mechanism used to transfer fluid (under pressure or vacuum) from a stationary inlet to a rotating outlet, preserving and isolating the fluid connection.
Pneumatic slip rings are engineered to endure a wide range of temperatures and pressures for a variety of conditions and environments. In addition, rotary unions may integrate multiple passages and handle different types of fluid simultaneously.
link:http://ja.btslipring.com/btq-02a
Hybrid Pneumatic slip ring