The invention is directed to a flexible pipe connecting unit which includes a
part made of elastic workable material. The pipe connecting unit includes a wave-shaped
or hose-shaped bellows (4) made of elastomeric material. The bellows (4)
has respective projecting flange collars (14; 14 a, 14b)
at its respective ends. The flange collars (14; 14a, 14b)
preferably are provided with a reinforcement insert (16; 16a,
16b) and annularly-shaped pipe connecting pieces (flanges 18; 18a,
16b) are disposed behind corresponding ones of the flange collars. The
pipe connecting unit (2) coacts directly with weld-on flanges as counter
flanges (20; 20a, 20b) without additional seals or
corresponding joining locations. For this purpose, the end sealing faces of the
flange collars (14; 14a, 14b) are partitioned in the
radial direction by a peripherally extending slot (28; 28a, 28b).
In this way, at least two coaxial concentric annularly-shaped sealing surfaces
(14-I, 14-II) are formed. With outer weld-on or slip-on flanges (20;
20a, 20b), only corresponding ones of the outer annular
sealing Surfaces (14-I) are in contact engagement and, when the counter
flange (20; 20a, 20b) is a welding-neck flange, at
least the outer sealing annular surface (14-I) comes into contact engagement.
A stabilization ring (32) can be implanted in the slot (28; 28a,
28b) of the flange collar (14; 14a, 14b)
between the outer annular sealing surface (14-I) and the inner annular sealing
surface (14-II).