Rotary joint

Abstract

A mechanical seal rotary joint of the end-face contact type which permits slurry fluids, such as polishing solution, to pass through a fluid passage without leaking out of the relatively rotating contact area therein. The rotary joint of the present invention comprises: a first joint body ( ); a second joint body ( ) connected rotatably to the first joint body ( ); a prime seal unit ( ) provided between the opposed end portions ( ) of the two joint bodies ( ); and a continuous line of prime fluid passage ( ). The prime seal unit ( ) is a mechanical seal comprising: a stationary seal ring ( ) fixed on the end portion ( ) of the second joint body ( ) concentrically with the axis of rotation as its center; a movable seal ring ( ) held on the end portion ( ) of the first joint body ( ) and concentric with and opposite to the stationary seal ring ( ); a rotation stopper ( ) provided on the outer circumferential side of the movable seal ring ( ) for preventing the relative rotation of the seal ring ( ) while allowing the seal ring ( ) to move in the axial direction; and springs ( ) to thrust and press the movable seal ring ( ) against the stationary seal ring ( ). Thus, the prime seal unit ( ) is constructed so as to provide a seal between the inner circumferential region ( ) and the outer circumferential region ( ) of the two seal rings ( ). The prime fluid passage ( ) is made up of the inner circumferential regions ( ) of the two seal ring ( ), a first primary passage section ( ) passing through the first joint body ( ) and leading into the inner circumferential region ( ) and a second prime fluid passage section ( ) passing through the second joint body ( ) and leading into the inner circumferential region ( ). A slurry fluid ( ), such as a polishing solution, flows through the prime fluid passage ( ) without leaking out of the relatively rotating section of the joint bodies ( ).