Piston ring arrangement

1. A piston ring arrangement, comprising:

a piston ring encircling a main axis (X), the piston ring having a sealing surface directed radially outward and a contact surface directed radially outward, the sealing surface being radially outside of the contact surface,

a retaining ring encircling the main axis (X) with a retaining surface directed radially inward,

the piston ring and the retaining ring being arranged such that the retaining surface and the contact surface are adjacent in the radial direction, and

wherein the retaining ring is a closed, unbroken ring.

2. The piston ring arrangement according to claim 1 , wherein the piston ring has a gap in the circumference.

3. The piston ring arrangement according to claim 1 , wherein the piston ring is pretensioned inward in the radial direction.

4. The piston ring arrangement according to claim 1 , wherein the contact surface runs oblique to the main axis (X) at an angle α≤45°.

5. The piston ring arrangement according to claim 1 , wherein the retaining surface runs oblique to the main axis (X) at an angle β≤45°.

6. The piston ring arrangement according to claim 1 , wherein the piston ring is one piece.

7. The piston ring arrangement according to claim 1 , wherein the retaining ring is one piece.

8. The piston ring arrangement according to claim 1 , wherein the retaining ring has at least one radially extending channel.

9. The piston ring arrangement according to claim 1 , wherein the piston ring consists of a first material with a modulus of elasticity E1, and the retaining ring consists of a second material with a modulus of elasticity E2, where E2>E1.

10. The piston ring arrangement according to claim 9 , wherein the first material is polytetrafluoroethylene (PTFE), a PTFE compound, or a PTFE-based composite material.

11. The piston ring arrangement according to claim 9 , wherein the second material is polyetheretherketone (PEEK), a PEEK compound, a PEEK-based composite material, or a metal.

12. A piston, comprising: a core extending along a main axis (X), encircled by at least two annular piston discs, the piston discs forming at least one groove open radially outward and encircling the main axis (X), and wherein a piston ring arrangement according to claim 1 is situated in the groove.

13. The piston according to claim 12 , wherein the piston ring arrangement is movable overall in the radial direction relative to the piston discs.

14. The piston according to claim 12 , wherein the piston discs have an L-shaped cross section.

15. The piston according to claim 12 , wherein the groove has a rectangular cross-section.

16. A reciprocating compressor having a liner extending along a main axis (X) and in which there is a piston that can move along the main axis (X) according to claim 12 .

17. The reciprocating compressor according to claim 16 , wherein the main axis (X) runs horizontally or obliquely.

18. The reciprocating compressor according to claim 16 , wherein the reciprocating compressor is single-acting and the piston ring arrangement is situated in the groove of the piston disc in such a way that the sealing section of the piston ring faces the low-pressure side (N).

19. The reciprocating compressor according to claim 16 , wherein the reciprocating compressor is double-acting and comprises a piston with several piston ring arrangements, the sealing sections of the piston rings of a part of the piston ring arrangements facing one side of the reciprocating compressor, and the sealing sections of the piston rings of the other part of the piston ring arrangements facing the other, opposite side of the reciprocating compressor.

20. A method, comprising the steps of:

obtaining the reciprocating compressor according to claim 16 , and compressing carbon monoxide (CO), oxygen (O 2 ) or hydrogen sulfide (H 2 S) with the reciprocating compressor.

21. A method, comprising the steps of: obtaining the reciprocating compressor according to claim 16 , and compressing gases to pressures above 150 bar.