US5037115A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Piston ring assemblies for high temperature seals
Assignee: Individual
•
Filing: 1989-09-11
•
Granted: 1991-08-06
•
Expires: 2009-09-11
Abstract
Abstract In a turbine inclusive of: a turbine shaft having a longitudinal axis, a steam pipe, a shell circumadjacent the pipe, the pipe and shell being shiftable in vertical and transverse and axial directions relative to the longitudinal axis of the shaft, and a seal assembly disposed between the pipe and shell and comprising a stack of interdigitated relatively large and small piston rings, the improvement comprising: each large ring loosely fitting inside the shell during nonoperative conditions and firmly and sealingly engaging the shell during operative conditions; and having a coefficient of thermal expansion greater than that of the shell for expanding at a rate faster than the expansion rate of the shell under a condition of increased temperature, each small ring loosely fitting around the pipe during nonoperative conditions and firmly and sealingly engaging the pipe during operative conditions; and having a coefficient of thermal expansion less than that of the pipe for expanding at a rate slower than the expansion rate of the pipe under a condition of increased temperature, with the large and small rings tightening upon the respective shell and pipe respectively under an increasing temperature condition and shrinking from the respective shell and pipe respectively under a decreasing temperature condition.
Inventors
- 👤 Ronald E. Brandon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:31
CPC Classifications
F; F01; F01D; F01D9/00; F01D9/06; F16; F16J; F16J15/00; F16J15/02; F16J15/06; F16J15/08; F16J15/0806; Y; Y10; Y10S; Y10S277/00; Y10S277/931
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
215 words
In a turbine inclusive of: a turbine shaft having a longitudinal axis, a steam pipe, a shell circumadjacent the pipe, the pipe and shell being shiftable in vertical and transverse and axial directions relative to the longitudinal axis of the shaft, and a seal assembly disposed between the pipe and shell and comprising a stack of interdigitated relatively large and small piston rings, the improvement comprising: each large ring (a) loosely fitting inside the shell during nonoperative conditions and firmly and sealingly engaging the shell during operative conditions; and (b) having a coefficient of thermal expansion greater than that of the shell for expanding at a rate faster than the expansion rate of the shell under a condition of increased temperature, each small ring (a) loosely fitting around the pipe during nonoperative conditions and firmly and sealingly engaging the pipe during operative conditions; and (b) having a coefficent of thermal expansion less than that of the pipe for expanding at a rate slower than the expansion rate of the pipe under a condition of increased temperature, with the large and small rings tightening upon the respective shell and pipe respectively under a decreasing temperature condition due to the relative coefficients of thermal expansion between the large and small rings and the respective shell and pipe.
Claim 2
Dependent Claim
215 words
In a turbine inclusive of: a turbine shaft having a longitudinal axis, a steam pipe, a shell circumadjacent the pipe, the pipe and shell being shiftable in vertical and transverse and axial directions relative to the longitudinal axis of the shaft, and a seal assembly disposed between the pipe and shell and comprising a stack of interdigitated relatively large and small piston rings, the improvement comprising: each large ring (a) loosely fitting inside the shell during nonoperative conditions and firmly and sealingly engaging the shell during operative conditions; and (b) having a coefficient of thermal expansion greater than that of the shell for expanding at a rate faster than the expansion rate of the shell under a condition of increased temperature, each small ring (a) loosely fitting around the pipe during nonoperative conditions and firmly and sealingly engaging the pipe during operative conditions; and (b) having a coefficent of thermal expansion less than that of the pipe for expanding at a rate slower than the expansion rate of the pipe under a condition of increased temperature, with the large and small rings tightening upon the respective shell and pipe respectively under a decreasing temperature condition due to the relative coefficients of thermal expansion between the large and small rings and the respective shell and pipe.
Claim 3
Dependent Claim
31 words
In a turbine as set forth in claim 1, wherein the small piston rings are fabricated from materials selected from any of the martensitic stainless steels for use at elevated temperatures.
Claim 4
Dependent Claim
35 words
In a turbine as set forth in claim 1, wherein the large piston rings are fabricated from materials selected from any of the austenitic stainless steels and precipitation hardening alloys intended for high temperature application.
Claim 5
Dependent Claim
34 words
In a turbine as set forth in claim 1, wherein the small piston rings are fabricated from low alloy steels intended for elevated temperature application with their contact surfaces overlay welded with cobalt-base alloys.
Claim 6
Dependent Claim
35 words
In a turbine as set forth in claim 1, wherein the large piston rings are fabricated from low alloy steels intended for elevated temperature application with their contact surfaces overlay welded with austenitic stainless steel.
Claim 7
Dependent Claim
33 words
In a turbine as set forth in claim 1, the further improvement of the addition of a surface lubricant to the pipe, shell and piston rings to minimize friction and oxide layer growth.
Claim 8
Dependent Claim
32 words
In a turbine as set forth in claim 6, wherein the surface lubricant to minimize friction and oxide layer growth comprises MOLYKOTE, a product of Dow Chemical Co., as a dry film.
Claim 9
Dependent Claim
29 words
In a turbine as set forth in claim 1, including spring means disposed between the piston rings and the shell for ensuring contact between piston rings at all times.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-08-05 | 1995-02-04 | 1995-08-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-08-05 | 1999-02-04 | 1999-08-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-08-05 | 2003-02-04 | 2003-08-06 | $7700.00 | Window Closed / Lapsed |