Patent US3736751A successfully refreshed from Google Patents.
US3736751A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gap control apparatus
Assignee: UK Secretary of State for Defence
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Filing: 1971-05-26
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Granted: 1973-06-05
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Expires: 1991-05-26
Abstract
Abstract In order to maintain a substantially constant clearance between static and rotating sealing elements of a gas turbine engine, one of the elements is connected to a thermally expansible control tube which is fed with hot gas from the engine in direct proportion to the size of the sealing clearance e.g. by using fluid which has leaked through the seal. The control tube is additionally fed with cold air and vented to a low pressure via a restrictor. When the seal clearance is set to the desired value the pressures of hot and cold fluid are such that there is no flow along the control tube. Enlargement of the clearance gives an increase in pressure to the hot fluid which flows along the tube heating the tube and the resulting expansion reduces the sealing clearance. Reduction in sealing clearance reduces the pressure of the hot fluid so that the colder fluid flows along the tube and the resulting contraction enlarges the sealing clearance.
Inventors
- 👤 J Rodney
- 👤 D Fuller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:19
CPC Classifications
F; F01; F01D; F01D11/00; F01D11/08; F01D11/14; F01D11/16; F01D11/18; F16; F16J; F16J15/00; F16J15/44; Y; Y10; Y10S; Y10S277/00; Y10S277/931
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
95 words
A self-adjusting clearance control mechanism for maintaining a clearance substantially constant at a desired value, comprising two members spaced apart to define the clearance, a temperature responsive control member which is arranged to expand or contract so as to act to produce relative movement between the two members in response to variations in its temperature, and means controlled by the size of the clearance for varying the temperature of the control member when the size of the clearance changes from said desired value so that the control member acts to oppose any variation in clearance.
Claim 2
Dependent Claim
95 words
A self-adjusting clearance control mechanism for maintaining a clearance substantially constant at a desired value, comprising two members spaced apart to define the clearance, a temperature responsive control member which is arranged to expand or contract so as to act to produce relative movement between the two members in response to variations in its temperature, and means controlled by the size of the clearance for varying the temperature of the control member when the size of the clearance changes from said desired value so that the control member acts to oppose any variation in clearance.
Claim 3
Dependent Claim
47 words
A clearance control mechanism according to claim 1 in which the temperature responsive control member is a metal tube and means are provided for connecting the tube at one end to one of the members defining the clearance and at the other end to a static structure.
Claim 4
Dependent Claim
31 words
A clearance control mechanism according to claim 2 in which the two members defining the clearance form parts of a seal between rotating and static parts of a gas turbine engine.
Claim 5
Dependent Claim
36 words
A clearance control mechanism according to claim 3 in which the seal comprises a non-rotating sealing ring, and a plurality of provided control tubes are provided connected to the ring at equal angularly spaced apart intervals.
Claim 6
Dependent Claim
41 words
A clearance control mechanism according to claim 4 in which the means for varying the temperature of the control member comprises a supply of hot control fluid from the engine, said supply varying directly with the size of the sealing clearance.
Claim 7
Dependent Claim
23 words
A clearance control mechanism according to claim 5 in which the hot control fluid is fluid which has leaked through the sealing clearance.
Claim 8
Dependent Claim
54 words
A clearance control mechanism according to claim 5 in which the control tube is supplied with hot control fluid at one end and with a relatively colder control fluid at the other end, and a vent being provided between the ends of the tube, said vent including a restriction to flow of fluid therethrough.
Claim 9
Dependent Claim
40 words
A clearance control mechanism accOrding to claim 7 in which the supply of said relatively colder control fluid originates from an environment in the engine which varies in pressure in proportion to the pressure conditions of the hot control fluid.
Claim 10
Dependent Claim
43 words
A clearance control mechanism according to claim 8 in which the engine is a by-pass gas turbine engine, air from a by-pass duct being used for the supply of said relatively colder air, and the control tube is vented to the by-pass duct.
Claim 11
Dependent Claim
135 words
A clearance control mechanism according to claim 8 in which the engine is a by-pass engine, the control tube is disposed in the by-pass passage of the engine and is surrounded by two further concentric tubes to define two annular flow passages around the tube, the hot control fluid being supplied to the control tube, at one end, the relatively colder control fluid being obtained from a source of hot fluid adjacent the seal and being passed down the outer of said two flow passages in contact with the outer tube so as to be cooled before being fed to the other end of the control tube, and vent means including flow restrictors being provided for venting both the control tube and the outer flow passages to the by-pass passage to maintain intermediate pressures therein.
Claim 12
Dependent Claim
52 words
A clearance control mechanism according to claim 10 in which the control tube is vented to the by pass passage via the inner of the flow passages surrounding the control tube so that at least part of the outer surface of the control tube is contacted by the high temperature control fluid.
Claim 13
Dependent Claim
119 words
A self adjusting clearance control mechanism for maintaining a clearance substantially constant at a desired value comprising two members spaced apart to define the clearance, a temperature responsive control member connected at one end to one of the members defining the clearance, and at the other end to a static structure, said control member being arranged to expand or contract so as to act to produce relative movement between the two members in response to variations in its temperature, and means controlled by the size of the clearance for varying the temperature of the control member when the size of the clearance changes from said desired value so that the control member acts to oppose any variation in clearance.
Claim 14
Dependent Claim
119 words
A self adjusting clearance control mechanism for maintaining a clearance substantially constant at a desired value comprising two members spaced apart to define the clearance, a temperature responsive control member connected at one end to one of the members defining the clearance, and at the other end to a static structure, said control member being arranged to expand or contract so as to act to produce relative movement between the two members in response to variations in its temperature, and means controlled by the size of the clearance for varying the temperature of the control member when the size of the clearance changes from said desired value so that the control member acts to oppose any variation in clearance.
References Cited (Backward Citations)
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US3146992A
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US3623736A
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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) | 1976-06-04 | 1976-12-04 | 1977-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-04 | 1980-12-04 | 1981-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-04 | 1984-12-04 | 1985-06-05 | $7700.00 | Window Closed / Lapsed |