Fluid rotary joint assembly suitable for high rotational speed

A fluid rotary joint assembly capable of high rotational speed exceeding a maximum rotational speed of a single rotary joint is disclosed herein. For example, the fluid rotary joint may be capable of exceeding rotational speeds greater than 1500 RPM. The fluid rotary joint assembly may have several single-stage fluid rotary joints and multiple gear devices wherein a relative speed between the first and second rotary parts of each single stage fluid rotary joint does not exceed a maximum rotary speed (e.g., 500 rpm). The fluid rotary joint assembly incorporates speed reduction within each stage through the gear device. By controlling the relative speed between the first and second parts of each of the fluid rotary joints to be less than or equal to a maximum allowable rotational speed (e.g., less than or equal to 500 RPM), the fluid rotary joint assembly provides for reliable operation at high rotational speeds between the first stage and the last stage.