Coupling for multi-walled lines

A coupling for connecting a first and a second multi-walled line each one having at least two concentric pipes, which are separated by a space, said coupling comprising:

• a female coupling part comprising at least two concentric tubes including an inner and an outer tube each connected at one end with one of the concentric pipes of the first multi-walled line, wherein the other ends of the at least two concentric tubes are joined in a fluid tight manner, wherein the inner tube is provided with a sealing surface;
• and
• a male coupling part comprising at least two concentric tubes including an inner and an outer tube each connected at one end with one of the concentric pipes of the second multi-walled line, wherein the other ends of the at least two concentric tubes are joined in a fluid tight manner,
• wherein the at least two concentric tubes of the female and/or male coupling parts are compressible and/or expandable in an axial direction,
• wherein the coupling comprises a seal that is arranged between the sealing surface of the female coupling part and a front end of the male coupling part, and
• wherein the sealing surface of the female coupling part is provided with a collar.