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US-12624762-B2 - Hydraulically supported face seal

US12624762B2US 12624762 B2US12624762 B2US 12624762B2US-12624762-B2

Abstract

A hydraulically supported seal including a seal plate operatively coupled with a seal, the seal being supported by a seal carrier within a housing; a piston having a piston shaft, the piston being in operative communication with the seal opposite the seal plate, the piston shaft being disposed through the housing through a piston receiver formed in the housing; a cylinder operatively coupled to the piston opposite the seal; and wherein the piston is hydraulically biased by a hydraulic fluid within the cylinder.

Inventors

  • Jorn A. Glahn

Assignees

  • RTX CORPORATION

Dates

Publication Date
20260512
Application Date
20250725

Claims (7)

  1. 1 . A process for hydraulically supporting a seal in a gas turbine engine, the process comprising: operatively coupling a seal plate with a seal; supporting the seal with a seal carrier within a housing; providing a piston having a piston shaft, the piston being in operative communication with the seal opposite the seal plate; disposing the piston shaft through a piston receiver formed in the housing; operatively coupling a cylinder to the piston opposite the seal; fluidly coupling a hydraulic circuit containing a hydraulic fluid to the cylinder; and hydraulically biasing the piston with the hydraulic fluid within the cylinder.
  2. 2 . The process of claim 1 , further comprising: operatively coupling a controller with the hydraulic circuit; and employing the controller to maintain a hydraulic circuit pressure which maintains a seal face integrity.
  3. 3 . The process of claim 1 , further comprising: sealing the interface between the piston and the cylinder with secondary seals.
  4. 4 . The process of claim 1 , further comprising: fluidly coupling a variable restrictor to the hydraulic circuit; and employing the variable restrictor to regulate pressure in the hydraulic circuit.
  5. 5 . The process of claim 1 , further comprising: pressurizing the hydraulic circuit with a pump.
  6. 6 . The process of claim 2 , wherein the controller is in communication with a supervisory controller.
  7. 7 . The process of claim 2 , further comprising: providing engine operational conditions as control input to the hydraulic circuit to maintain sealing forces acting on a carbon seal throughout at least one engine operating cycle.

Description

This application is a divisional of U.S. patent application Ser. No. 18/061,808, filed Dec. 15, 2022. BACKGROUND The present disclosure is directed to a high pressure cylinder integrated into a housing for a face seal to improve sealing with use of a very high pressure CO2 working fluid system. Waste heat recovery systems are configured to capture the thermal energy in the engine exhaust and transfer the thermal energy to a working fluid, such as supercritical CO2 or air. The working fluid is then sent through a thermodynamic cycle to produce power in the form of electricity or mechanical motion. This power is used to supplement engine thrust. The use of supercritical CO2 as a working fluid in the waste heat recovery system requires very high pressure systems and resultant pressure differentials across sealing surfaces (1,000 psi). As seen in FIGS. 1 to 3 typical face seals include a seal plate interacting with a carbon seal supported by a carbon carrier in a housing. FIG. 1 shows a bearing compartment with a face seal highlighted. FIG. 2 and FIG. 3 show a seal plate A proximate a low pressure Plow section. A carbon seal B is adjacent the seal plate A on the high pressure Phigh section. A carbon carrier C supports the carbon seal B. A damper D is coupled to a biasing member or spring S. The carbon seal B is biased by the mechanical spring S, such as a bellows spring or coil spring. The forces mustered by the bellows spring have a fixed limited range (100-150 psi) and can degrade over time. What is needed is an improved face seal system capable of withstanding very high pressure differentials. SUMMARY In accordance with the present disclosure, there is provided a hydraulically supported seal comprising a seal plate operatively coupled with a seal, the seal being supported by a seal carrier within a housing; a piston having a piston shaft, the piston being in operative communication with the seal opposite the seal plate, the piston shaft being disposed through the housing through a piston receiver formed in the housing; a cylinder operatively coupled to the piston opposite the seal; and wherein the piston is hydraulically biased by a hydraulic fluid within the cylinder. A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the seal plate is between a high-pressure section and a low-pressure section opposite the high-pressure section. A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the seal is adjacent the seal plate on the low-pressure side of the seal plate. A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the piston shaft within the piston receiver is sealed by a non-rotating secondary seal. A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the hydraulically supported seal further comprising a hydraulic circuit fluidly coupled to the cylinder, the hydraulic circuit configured to pressurize the cylinder. A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include secondary seals seal the piston and the cylinder interface. A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the hydraulically supported seal further comprising a controller employed to maintain the hydraulic circuit pressure which maintains a seal face integrity. In accordance with the present disclosure, there is provided a system for hydraulically supporting a seal in a supercritical carbon dioxide (sCO2) turbomachine comprising a supercritical carbon dioxide turbomachine seal plate operatively coupled with a seal, the seal being supported by a seal carrier within a housing located in the supercritical carbon dioxide turbomachine; a piston having a piston shaft, the piston being in operative communication with the seal opposite the seal plate, the piston shaft being disposed through the housing through a piston receiver formed in the housing; a cylinder operatively coupled to the piston opposite the seal; and a hydraulic circuit containing a hydraulic fluid fluidly coupled to the cylinder, the hydraulic circuit configured to pressurize the cylinder, wherein the piston is hydraulically biased by the hydraulic fluid within the cylinder. A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the system for hydraulically supporting a seal in a supercritical carbon dioxide turbomachine, further comprising a controller employed to maintain the hydraulic circuit pressure which maintains a seal face integrity. A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the seal plate is between a high-pressure section and a low-pressure section. A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the hydraulic ci