Pressure build-up mandrel for securing a tube in a tube plate or the like

摘要

In the case of a pressure build-up mandrel (5) for fixing a tube (2) in a tube plate (1) or the like, having an elongate core (6), two clamping cones (10,11) bounding an expansion region (9) and a spacer sleeve (12) arranged between the clamping cones (10,11), in which the clamping cones (10,11) have oblique surfaces (14, 15) facing the spacer sleeve (12) and form two encircling seal-receiving grooves (16, 17), a seal (18, 19) is arranged in each of the seal-receiving grooves (16, 17) and preferably in each case one radially expandable back-up ring (20, 21) sliding on the oblique surface (14, 15) of the corresponding clamping cone (10, 11) is provided and in which presealing of the expansion region (9) can be achieved mechanically, tearing apart can be reliably prevented, even where the diameter of the pressure build-up mandrel is small, and difficulties in the withdrawal of the pressure build-up mandrel from the end of the tube no longer occur since both clamping cones (10, 11) are arranged in a fixed location on the core (6), a prestressing cone (22) is arranged at a fixed location on the core (6) in the expansion region (9), immediately adjoining the clamping cone (11) near the connection end (8) of the core (6), the oblique surface (23) of the prestressing cone (22) faces the adjoining clamping cone (11) and helps to form the corresponding seal-receiving groove (17) and, to achieve the presealing of the expansion region (9) the spacer sleeve (12) [...] the seals (18, 19) and, if present, the ... Original abstract incomplete. <IMAGE>