Fluid duct

1. Fluid duct ( 8 ) comprising a fluid duct connection end portion ( 12 ) for coupling to a component connection end portion ( 4 ), the fluid duct connection end portion ( 12 ) comprising a clamping ring seat ( 14 ) configured for receiving an adjustable clamping ring therearound, the clamping ring seat ( 14 ) extending axially (A) between an entry section ( 16 ) and a tube joining section ( 18 ), the tube joining section ( 18 ) extending into a fluid duct tube portion ( 10 ), wherein the clamping ring seat ( 14 ) comprises an expansion fold ( 20 ) configured to allow at least a portion of the clamping ring seat ( 14 ) to expand radially due to a widening of the expansion fold ( 20 ); wherein the expansion fold comprises a plurality of oblique sections ( 20 a ) extending at least partially in a circumferential direction and at least partially in a radial direction with respect to the clamping ring seat; and wherein the oblique sections comprise at least a pair of oblique sections that converge towards an apex.

2. Fluid duct according to claim 1 , wherein the expansion fold forms a continuous path circumscribing the clamping ring seat.

3. Fluid duct according to claim 1 , wherein the expansion fold comprises a wave shape section including a pair of oblique sections.

4. Fluid duct according to claim 3 , wherein the wave shape section extends over a circumferential angle of between 10° and 170° with respect to the circumference of the clamping ring seat.

5. Fluid duct according to claim 4 , wherein the wave shape section extends over a circumferential angle of between 10° and 60°, with respect to the circumference of the clamping ring seat.

6. Fluid duct according to claim 1 , wherein the expansion fold comprises a pair of wave shaped sections arranged evenly around the axis (A) of the fluid duct connection end portion.

7. Fluid duct according to claim 1 , wherein the expansion fold comprises oblique sections that extend essentially from a first edge of the clamping ring seat to an opposed second edge of the clamping ring seat, the first and second edges at opposed axial ends of the clamping ring seat.

8. Fluid duct according to claim 1 , wherein the tube joining section comprises a tapered radially outward section ( 25 ) extending from the clamping ring seat and a tapered radially inward section ( 24 ) extending to a fluid duct tube portion ( 10 ), an inner surface ( 22 ) of the tube joining section receiving a compression sealing protrusion ( 32 ) of a sealing ring ( 6 ) thereagainst.

9. Fluid duct according to claim 8 , wherein the fluid duct connection end portion couples to the component connection end portion via the sealing ring ( 6 ) configured to extend along an inner surface of the fluid duct connection end portion from the entry section to the tube joining section.

10. Fluid duct according to claim 9 , wherein the sealing ring comprises an entry flange ( 26 ) configured to abut against the entry flange of the fluid duct, a mid-section ( 28 ) extending along an inner surface of the clamping ring seat, and an end section ( 30 ) comprising a compression sealing protrusion ( 32 ) extending radially outwardly for compression against the inner surface of the tube joining section.

11. Fluid duct according to claim 10 , wherein the end section of the sealing ring comprises at least one flexible sealing lip ( 34 ) in addition to the compression sealing protrusion.

12. Fluid duct according to claim 8 , wherein the sealing ring comprises an elastomeric polymer.

13. Fluid duct according to claim 1 , wherein the fluid duct connection end portion is made of a blow molded polymer.

14. Fluid duct according to claim 1 , wherein the expansion fold is in the form of an inwardly indented groove protruding radially inwardly.

15. Fluid duct according to claim 1 , wherein the expansion fold has a width in the range of 0.25 to 3 times the wall thickness of the clamping ring seat.

16. Fluid duct according to claim 15 , wherein the expansion fold has a width in the range of 0.5 to 2 times the wall thickness of the clamping ring seat.

17. Fluid duct according to claim 1 , wherein the expansion fold comprises a groove protruding radially inwardly, a radial depth of the groove in a range of 0.25 to 2 times the thickness of a wall of the clamping ring seat.

18. Fluid duct according to claim 1 that is made of a thermoplastic resin.