Device for prestressing bolts attaching covers of pressure vessels, particularly reaction pressure vessels

摘要

The present invention relates to a device for prestressing bolts attaching covers of pressure vessels, particularly reactor pressure vessels, which device comprises independent prestressing units (9) with prestressing nuts (16) screwed on bolt stems (4) arranged therein. The prestressing nuts (16) outside diameter is provided with a reduction (26) in a portion of their length, while a bulge (28) engaging with said reduction (26) is performed in corresponding pressure bridges (14) of the prestressing units (9) through hole (15) upper part. In such a way reinforcement of the pressure bridges with possibility of their very thin make is achieved.