Drain pipe arrangement and gas turbine engine comprising a drain pipe arrangement

1. A pipe arrangement for a turbomachine for drainage of lube oil from bearings, comprising:

a fluid pipe for guiding fluids, the fluids being the lube oil, from the bearings of the turbomachine and a coupling element for coupling the fluid pipe to an outer casing of the turbomachine, wherein

the coupling element is configured to provide a first connection between the coupling element and the outer casing of the turbomachine by a first end of the coupling element that is secured to the outer casing of the turbomachine in a manner effective to prevent movement of the coupling element relative to the outer casing of the turbomachine,

the coupling element provides a second connection between the coupling element and a first surface section of the fluid pipe by a second end of the coupling element, wherein

the fluid pipe comprises an area of reduced outer diameter that forms the first surface section, wherein the coupling element abuts a step in the fluid pipe adjacent the first surface section, effective as a stop to prevent movement of the first surface section toward the first end of the coupling element

the coupling element comprises a sleeve portion surrounding a second surface section of the fluid pipe and being spaced apart to the second surface section of the fluid pipe,

wherein the sleeve portion extends from the first end of the coupling element to the second end of the coupling element and comprises an inner diameter that does not vary along an entire axial length of the sleeve portion, wherein an area of contact between the coupling element and the fluid pipe is limited to the second connection, and

wherein the fluid pipe comprises a first pipe section that fully pierces the outer casing of the turbomachine and a second pipe section projecting from the outer casing of the turbomachine, the first pipe section being contact-less where piercing the outer casing of the turbomachine, and

wherein the second end of the coupling element comprises a mating surface facing an axis of symmetry of the coupling element for mating the first surface section of the fluid pipe, the first surface section facing away from an axis of symmetry of the fluid pipe.

2. The pipe arrangement according to claim 1 ,

wherein the sleeve portion is spaced apart to the second surface section of the fluid pipe to form a cavity following a shape of a side face of a cylinder or a side face of an elliptic cylinder or a side face of a truncated cone, or

wherein the cavity has a rectangular or triangular or square cross section.

3. The pipe arrangement according to claim 2 , wherein

the cavity is built such that the fluid pipe has an unvaried cross section or wall thickness or diameter over an axial expanse of the second surface section and the coupling element comprises a section of increased cross section or wall thickness or diameter, or

the cavity is built such that the fluid pipe comprises a section of reduced cross section or wall thickness or diameter and the coupling element has an unvaried cross section over an axial expanse of the coupling element, or

the cavity is built such that the fluid pipe comprises the section of reduced cross section or wall thickness or diameter and the coupling element comprises the section of increased cross section or wall thickness or diameter.

4. The pipe arrangement according to claim 2 ,

wherein the sleeve portion is free of passages to the cavity.

5. The pipe arrangement according to claim 1 ,

wherein the sleeve portion is spaced apart to the second surface section of the fluid pipe to form a cavity with opposing surfaces having an identical distance to each other.

6. The pipe arrangement according to claim 1 ,

wherein the sleeve portion of the coupling element is continuously spaced apart to the second surface section without any struts or means for stabilizing.

7. The pipe arrangement according to claim 1 ,

wherein the first end of the coupling element is spaced apart from the second surface section of the fluid pipe and the first end of the coupling element is not in physical contact with the fluid pipe at the first end of the coupling element.

8. The pipe arrangement according to claim 1 ,

wherein the sleeve portion is spaced apart from the second surface section of the fluid pipe to form a cavity and the cavity extends over the sleeve portion and the first end.

9. The pipe arrangement according to claim 1 ,

wherein the first end of the coupling element is arranged as a flange, collar, or shroud.

10. The pipe arrangement according to claim 9 , wherein the first end of the coupling element is arranged as a flange oriented perpendicular to the axis of symmetry of the coupling element.

11. The pipe arrangement according to claim 1 , wherein

the fluid pipe and the coupling element are built monolithic, or

the fluid pipe and the coupling element are separate parts and the second connection is provided by welding, brazing, shrink fitting, threading, or clamping on.

12. A fluid inlet or outlet arrangement comprising the pipe arrangement according to claim 1 , and

the outer casing of the turbomachine to which the pipe arrangement is connected via the first connection between the coupling element and the outer casing of the turbomachine by the first end of the coupling element.

13. The fluid inlet or outlet arrangement according to claim 12 ,

wherein the first end of the coupling element is configured as a flange, and the first connection between the coupling element and the outer casing of the turbomachine by the first end of the coupling element is provided by at least one connecting member inserted into a bore hole through the flange of the first end.

14. The fluid inlet or outlet arrangement according to claim 13 ,

wherein the at least one connecting member comprises a bolt or a stud or a screw.

15. The fluid inlet or outlet arrangement according to claim 12 ,

wherein the fluid pipe is oriented in a 20° to 50° angle in regards to a vertical axis.

16. The fluid inlet or outlet arrangement according to claim 15 ,

wherein the fluid pipe is oriented in a 30° to 45° angle, in regards to the vertical axis.

17. A gas turbine engine, comprising

a compressor, a combustor, a turbine, and

the fluid inlet or outlet arrangement according to claim 12 , wherein the fluid pipe is located upstream of a compressor inlet or downstream of a compressor exit, a location downstream of the compressor exit being in a turbine section of the gas turbine engine or a transition section between a compressor section and the turbine section of the gas turbine engine.

18. A pipe arrangement for a gas turbine engine for drainage of lube oil from bearings, comprising:

a fluid pipe for guiding fluids, the fluids being the lube oil, and a coupling element for coupling the fluid pipe to an outer casing of the gas turbine engine, wherein

the fluid pipe is located upstream of a compressor inlet or downstream of a compressor exit,

a location downstream of the compressor exit being in a turbine section of the gas turbine engine or a transition section between a compressor section and the turbine section of the gas turbine engine, wherein

the coupling element is configured to provide a first connection between the coupling element and the outer casing of the gas turbine engine by a first end of the coupling element,

the coupling element provides a second connection between the coupling element and a first surface section of the fluid pipe by a second end of the coupling element, wherein the first surface section of the fluid pipe comprises an outer surface of reduced outer diameter facing radially outward with respect to an axis of symmetry of the fluid pipe, and wherein a radially inward facing surface of the coupling element contacts the first surface section and the coupling element abuts a step in the fluid pipe adjacent the first surface section, effective as a stop to prevent movement of the first surface section toward the first end of the coupling element,

the coupling element comprises a sleeve portion surrounding a second surface section of the fluid pipe and being spaced apart to the second surface section of the fluid pipe, wherein the sleeve portion extends from the first end of the coupling element to the second end of the coupling element and comprises an inner diameter that does not vary along an entire axial length of the sleeve portion, wherein an area of contact between the coupling element and the fluid pipe is limited to the second connection,

wherein the fluid pipe comprises a first pipe section that pierces the outer casing of the gas turbine engine and a second pipe section projecting from the outer casing of the gas turbine engine, the first pipe section being contact-less where piercing the outer casing of the gas turbine engine and

wherein the fluid pipe and the coupling element are formed from a monolithic body or are immovably secured to each other.