US Patent 7467814 Flange

A flange for connecting pipes. The flange includes a fixing flange and a connecting flange and a joint fastening member. Each of the fixing flange and the connecting flange has a bolt facing groove on a peripheral edge of each flange and a nut fixing groove formed adjacent to the bolt facing groove. The joint fastening member includes a screw bolt, a first fixing nut screwed to a first end of the screw bolt, and a second fixing nut screwed to a second end of the screw bolt. The first fixing nut has a joint protrusion that is inserted into the nut fixing groove of the fixing flange, and the second fixing nut has a joint protrusion that is inserted into the nut fixing groove of the connecting flange.