Deformable sealing plug and process for plugging a cavity using such a sealing plug

A sealing plug configured to be arranged inside a cavity in order to plug said cavity leaktightly, the sealing plug comprising:

• an envelope configured to be deformed incompressibly, the envelope delimiting a hollow internal space and being provided with at least one orifice capable of making said hollow internal space communicate with an outside of the envelope;
• a rod which is configured to slide through the envelope and extend on either side of said envelope, the rod comprising a first end provided with a head configured to exert a compressive force on the envelope in order to deform the envelope when a second end of the rod is moved so as to pull the head against the envelope;
• a viscous seal arranged in the hollow internal space of the envelope;
• and
• a non-return part arranged on the rod, in the hollow internal space of the envelope and extending transversely with respect to the rod, the non-return part being configured to guide the viscous seal toward the at least one orifice in the envelope when said envelope is deformed, and to prevent the viscous seal from backing up into the hollow internal space, and
• wherein the sealing plug is configured such that the viscous seal is at least partially expelled from the envelope through the at least one orifice when the envelope is deformed by the head of the rod.