Patent ID: 7422031

Claim:
A rotary union, comprising: a housing having a fluid path through which a fluid can be conveyed through the housing; a rotor having a fluid path through which a fluid can be conveyed through the rotor, wherein the rotor is rotatably coupled to the housing; at least a first and a second unlubricated bearings interposed between a portion of the rotor exterior and a portion of the housing interior, wherein the first and second bearings are spaced apart and rotatably couple the rotor and the housing; a spacer member positioned between the first and second bearings, wherein an annular gap is between the spacer and the rotor, wherein the gap between the spacer and the rotor extends along the length of the spacer; a post having a fluid path through which a fluid can be conveyed through the post, said post being positioned in the rotary union in a manner effective to help fluidly couple the rotor fluid path and the housing fluid path such that a fluid can be transferred between the housing and the rotor via the post fluid path; and an annular gap surrounding at least a portion of the post, wherein the annular gap constitutes at least a portion of a drain pathway through which a portion of fluid conveyed through the housing fluid path is drained from the rotary union.