Expanding elastomer/plug device for sealing bore hole and pipelines

A downhole plug with an expandable elastomeric packer (1) having two ends, extending around a main section (25), for use in sealing wellbores and tubulars (4),

• characterized by:
• at least one expansion ring (13) adjoining at least one of said two ends of the elastomeric packer (1) provided with a split groove (17) that can be opened to allow the ring (13) to expand in a radial direction, wherein at the end of the split groove, there is a frangible piece (18) including a small portion of material keeping expansion rings (13) together during assembly and until an axial force (16) is applied, wherein said split groove (17) is slanted at the point at which the gap opens;
• at least one guide ring (14) having tapered surfaces conducive to the expansion of the elastomeric packer (1) and the at least one expansion ring (13);
• at least one support ring (15) for exerting an axial force (16) in a longitudinal direction of the downhole plug;
• at least one of said two ends of the elastomeric packer (1) being provided with a tapered surface;
• and
• wherein the at least one expansion ring (13) being provided with a tapered surface configured in such a manner that the application of the axial force (16) in the longitudinal direction of the downhole plug results in the simultaneous expansion of the elastomeric packer (1) and the at least one expansion ring (13).