Screw connection to fasten fittings to pipe elements consists of union nut screwed on and projecting with one end over outer thread of tube element, and securing ring to prevent unscrewing

摘要

The connection unit comprises of a tube element (20) with outer thread (21), and a union nut (10) with inner thread (11). When screwed onto the tube element, the nut projects with one end (12) axially over the outer thread of the element. A securing device (30) acts with the projecting end to prevent the union nut from being unscrewed from the tube element. The projecting end has a second inner thread (13) with a core diameter (d), which is larger than the outer diameter (D) of the outer thread of the tube element, and has a different pitch and/or direction from the first inner diameter. The securing device is a ring pref. a half ring, and has shoulders (32) for a special tool.