Abstract: A union joint capable of perfectly hermetically connecting pipes so that a gas passing the pipes never leaks from the junction of the pipes even if the pressure of the gas is as high as 150 kg/cm.sup.2. The union joint comprises a first sleeve hermetically joined to a pipe, a second sleeve hermetically joined to another pipe to be connected to the pipe joined to the first sleeve, one or a plurality of metallic gaskets placed between the respective sealing surfaces of the first and second sleeves so as to be compressed between the sealing surfaces of the first and second sleeves when the first and second sleeves are drawn axially toward each other, a coupling nut for drawing the first and second sleeves axially toward each other, and a thrust bearing interposed between the first sleeve and the coupling nut to allow the coupling nut to be rotated relative to the first sleeve.

Abstract: A union joint capable of connecting two pipes in a perfectly sealed joint. The union joint comprises a first sleeve hermetically joined to a first pipe, a second sleeve hermetically joined to a second pipe, a metallic gasket interposed between the first and second sleeves so as to be compressed between the respective pressing surfaces of the first and second sleeves when the first and second sleeves are drawn axially toward each other and a coupling nut combined with the first sleeve so as to be screwed on the second sleeve to draw the first and second sleeves axially toward each other.

Abstract: A superfine finish piping joint has a metal C ring disposed between a couple of joint pieces, the piping joints being capable of properly tightening the metal C ring for thereby being usuable for piping to a clean room. The superfine finish piping joint includes, besides a couple of the first and second joint pieces, a box nut, a thrust bearing disposed between a base portion of second joint piece facing to the internal end surface of an box nut, and a cup-shaped retainer serving to mount balls and rings, etc., of the thrust bearing as a whole on the second joint piece, etc., at prescribed positions.