Methods and systems for preventing lube oil leakage in gas turbines

Patent metadata

Field	Value
Publication number	US-10082041-B2
Application number	US-201414783602-A
Country	US
Kind code	B2
Filing date	Apr 9, 2014
Priority date	Apr 10, 2013
Publication date	Sep 25, 2018
Grant date	Sep 25, 2018

Abstract

A sump pressurization system comprising an off-board source of pressurized air is provided to supplement pressurized air to a bearing sump arrangement when the operating conditions of the gas turbine engine are such that the on-board pressurized air source, e.g. the compressor of the gas generator, are such that the air pressure generated thereby is insufficient to pressurize a sump pressurization cavity. A gas turbine engine comprising such a sump pressurization system is also provided, as is a corresponding method for operating a gas turbine engine to facilitate reducing leakage of lubrication oil.

First claim

What is claimed is:

1. A method for operating a gas turbine engine to facilitate reducing leakage of lubrication oil, the gas turbine engine comprising: at least one bearing assembly arranged in a sump oil cavity, and a sump pressurization cavity at least partly encasing the sump oil cavity and in fluid communication therewith; the method comprising the steps of: supplying sump pressurization air to the sump pressurization cavity from an air source on-board of said gas turbine engine, to maintain in said sump pressurization cavity an operating pressure higher than a pressure in said sump oil cavity; when air pressure from the air source on-board of the gas turbine engine is insufficient to maintain said operating pressure in the sump pressurization cavity, supplying supplemental sump pressurization air to said sump pressurization cavity from at least one auxiliary pressurized-air source external to and independent of the gas turbine engine.

2. The method of claim 1 , wherein the step of supplying supplemental sump pressurization air comprises operating an air blower.

3. The method of claim 2 , wherein the step of supplying supplemental sump pressurization air comprises operating the air blower at a variable rotation speed to maintain the operating pressure in the sump pressurization cavity.

4. The method of claim 1 , wherein the sump pressurization cavity comprises first sealing members for sealing first shaft passageways between the sump oil cavity and the sump pressurization cavity, and second sealing members for sealing second shaft passageways between the sump pressurization cavity and a surrounding environment; and
wherein the operating pressure in the sump pressurization cavity is maintained at a level sufficient to prevent air from penetrating through the second sealing members inside the sump pressurization cavity.

5. The method of claim 1 , further comprising the steps of detecting a pressure which is indicative of a pressure inside the sump pressurization cavity; if the detected pressure is below a minimum sump pressure threshold, fluidly connecting the sump pressurization cavity with a supplemental pressurized-air delivery line and delivery supplemental sump pressurization air through said supplemental air delivery line to the sump pressurization cavity.

6. The method of claim 1 , wherein: the sump pressurization cavity is in fluid communication with a pressurized air duct, said pressurized air duct being in fluid communication selectively with an on-engine source of pressurized air on the gas turbine engine and with an off-engine supplemental air delivery line;
wherein a first valve arrangement is provided between the gas turbine engine and the pressurized air duct and a second valve arrangement is provided between the supplemental air delivery line and said at least one auxiliary pressurized-air source; and
wherein said method comprises the step of closing the first valve arrangement and opening the second valve arrangement when the air pressure from the on-engine source of pressurized air is insufficient to maintain said operating pressure in the sump pressurization cavity.

7. A sump pressurization system for a gas turbine engine, comprising: a sump oil cavity housing a bearing assembly; a sump pressurization cavity at least partly encasing said sump oil cavity and in flow communication therewith; a supplemental pressurized-air delivery line for flow connection between the sump pressurization cavity and at least one auxiliary pressurized-air source external to and independent of the gas turbine engine; a pressurized-air line for flow connection between the sump pressurization cavity and the gas turbine engine; and a valve arrangement for connecting the sump pressurization cavity selectively with the pressurized-air line, or with the supplemental pressurized-air delivery line.

8. The sump pressurization system of claim 7 , wherein the supplemental pressurized-air delivery line is configured for flow connection with said at least one auxiliary pressurized-air source and a further auxiliary pressurized-air source.

9. The sump pressurization system of claim 7 , wherein said at least one auxiliary pressurized-air source comprises a blower.

10. The sump pressurization system of claim 8 , wherein said further auxiliary pressurized-air source comprises a blower.

11. The sump pressurization system of claim 9 , wherein said blower is driven by a variable-speed driver.

12. The sump pressurization system of claim 7 , further comprising a scavenge pump in fluid communication with the sump oil cavity.

13. A gas turbine engine comprising:
at least one bearing assembly; and
a sump pressurization system configured to supply lubrication oil to the bearing assembly, the sump pressurization system being in accordance with claim 7 , said bearing assembly being arranged in the sump oil cavity.

14. A gas turbine engine comprising: at least one bearing assembly; a sump pressurization system comprised of: a sump oil cavity encasing said bearing assembly, and a sump pressurization cavity, wherein the sump oil cavity is at least partly encased within the sump pressurization cavity and in flow communication therewith; a pressurized-air connection line fluidly connecting said sump pressurization cavity and an air source of said gas turbine engine; a supplemental pressurized-air connection line fluidly connecting the sump pressurization cavity with at least one auxiliary pressurized-air source external to and independent of the gas turbine engine; and a valve arrangement for fluidly connecting the sump pressurization cavity selectively with the pressurized-air connection line and with the supplemental pressurized-air connection line.

15. The gas turbine engine of claim 14 , wherein the air source of the gas turbine engine comprises said at least one air compressor of the gas turbine engine.

16. The gas turbine engine of claim 15 , wherein said valve arrangement is arranged and controlled to connect the sump pressurization cavity with the supplemental pressurized-air source when the pressurized air delivered by the gas turbine is insufficient to maintain an operating pressure value in the sump pressurization cavity.

17. The gas turbine engine of claim 14 , further comprising a second auxiliary pressurized-air source.

18. The gas turbine engine of claim 17 , wherein said valve arrangement comprises:
first valve members to establish a fluid connection between the sump pressurization cavity and the pressurized-air connection line;
second valve members to establish a fluid connection between the sump pressurization cavity and said at least one auxiliary pressurized-air source; and
third valve members to establish a fluid connection between the sump pressurization cavity and said second auxiliary pressurized-air source.

19. The gas turbine engine of claim 14 , wherein said at least one auxiliary pressurized-air source comprises a blower.

20. The gas turbine engine of claim 14 , wherein said valve arrangement is arranged and controlled to alternatively establish a fluid connection between the sump pressurization cavity and the pressurized-air connection line and close the supplemental pressurized-air connection line; or close the pressurized-air connection line and establish a fluid connection between the sump pressurization cavity and the supplemental pressurized-air connection line.

Assignees

• Nuovo Pignone Srl

Inventors

• Bei Simone
• Marcucci Daniele
• Hofman Maciej
• Lazzeri Marco

Classifications

• F01D25/16

  Arrangement of bearings; Supporting or mounting bearings in casings (bearings per se F16C) · CPC title

• F01D11/06 Primary

  Control thereof · CPC title

• F01D25/183

  Sealing means · CPC title

• F04D19/002

  Axial flow fans · CPC title

• F01D25/20 Primary

  using lubrication pumps · CPC title