GB2190155A - Metallic sealing rings - Google Patents

Metallic sealing rings Download PDF

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Publication number
GB2190155A
GB2190155A GB08710127A GB8710127A GB2190155A GB 2190155 A GB2190155 A GB 2190155A GB 08710127 A GB08710127 A GB 08710127A GB 8710127 A GB8710127 A GB 8710127A GB 2190155 A GB2190155 A GB 2190155A
Authority
GB
United Kingdom
Prior art keywords
sealing ring
loop
metallic sealing
hollow metallic
limbs
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08710127A
Other versions
GB8710127D0 (en
GB2190155B (en
Inventor
Michael John Caswell Tozer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Heat Transfer Technology Ltd
Original Assignee
Heat Transfer Technology Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB08610771A external-priority patent/GB2189850A/en
Application filed by Heat Transfer Technology Ltd filed Critical Heat Transfer Technology Ltd
Priority to GB8710127A priority Critical patent/GB2190155B/en
Publication of GB8710127D0 publication Critical patent/GB8710127D0/en
Publication of GB2190155A publication Critical patent/GB2190155A/en
Application granted granted Critical
Publication of GB2190155B publication Critical patent/GB2190155B/en
Expired legal-status Critical Current

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16JPISTONS; CYLINDERS; SEALINGS
    • F16J15/00Sealings
    • F16J15/02Sealings between relatively-stationary surfaces
    • F16J15/06Sealings between relatively-stationary surfaces with solid packing compressed between sealing surfaces
    • F16J15/08Sealings between relatively-stationary surfaces with solid packing compressed between sealing surfaces with exclusively metal packing
    • F16J15/0887Sealings between relatively-stationary surfaces with solid packing compressed between sealing surfaces with exclusively metal packing the sealing effect being obtained by elastic deformation of the packing

Abstract

A hollow metallic sealing ring comprises in radial cross-section of a pair of outwardly convex limbs (1) contiguous with a loop formation (3, 3a) having at least one straight sided loop, the limbs (1), from their junctions with the ends of the loop formation (3, 3a) being of increasing radius (T>S) towards their free ends (1a) which are straight and substantially parallel. <IMAGE>

Description

SPECIFICATION Hollow metallic sealing ring This invention relates to hollow metallic sealing rings of the so-called low-load self-energising static kind as used for instance in pumps, motors and other apparatus to form leakproof seals between opposed, usually plane, parallel surfaces.
Conventional metallic sealing rings for this purpose are of 'C' or 'O' shaped radial crosssection but these have a major disadvantage in that they have a high spring rate and for many applications when the seal must have a large diameter the resultant compressive loads required are extremely high and not suited to the relatively weak flanges such as are used, for example, on aero engines.
Difficulties also arise when the gap to be sealed between surfaces or flanges is relatively large as happens with certain engines because of the need to cater for the manufacturing tolerances in assembly of the various parts of the engine which determine the relative position of the flanges. Further, this accumulated tolerance is compounded by differential expansion of the flanges both longitudinaliy and radially. There is therefore constant movement as the engine temperature varies from cold to hot and sealing contact points are not of constant diameter. The sealing ring must accordingly be sufficiently resilient to cope with large amounts of radial and axial expansion and contraction.
To this end, various forms of sealing ring which, in radial section, are of concertina or bellows-shaped profile have been proposed and comprise two outer limbs, intended to engage the surfaces or flanges to be seated connected by one or more contiguous loops.
Typical examples of such metallic sealing rings are those which are disclosed in U.S.A. Patent Specifications 3575432, 3797836 and 4121843. In each of those examples the outer limbs are of sinuous configuration with curved extremities which make line contact with the surfaces or flanges to be sealed.
The present invention has been devised with the object of providing a sealing ring which has a superior performance compared with the sealing rings which have been hitherto proposed and/or used.
In accordance with the present invention a hollow metallic sealing ring is comprised in radial cross-section of a pair of outwardly convex limbs which extend from the ends of a loop formation having at least one contiguous straight sided loop, the limbs, from their junctions with the ends of the loop formation, being of increasing radius towards their free ends which are straight and substantially parallel. Preferably the radius of the curved end of the loop is considerably less than the minimum radius of the aforesaid outwardly convex limbs. Also where there is more than one loop, individual loops may be of different width.
Some particular and at present preferred embodiments of the invention are illustrated in the accompanying drawings, in which: Fig. 1 is a plan view of a single loop sealing ring; and Fig. 2 is an enlarged scale radial cross-section on line A-A of Fig. 1; Figs. 3, 3A, 3B and 3C are diagrammatic views to illustrate four stages in the formation of a particular sealing ring; Figs. 4, 4A, 4B and 4C similarly illustrate stages in the formation of a sealing ring with alternative limb and central loop radii; Figs. 5, 5A, 5B, 5C and 5D similarly illustrate changes in the loop length and straight limb part length of a sealing ring; and Figs. 6, 7, 8 and 9 are cross-sections of four different plural loop embodiments of the invention.
Referring firstly to Figs. 1 and 2 of the drawings, the hollow metallic sealing ring therein shown is intended for a turbine gas path aircraft engine and is made of a metal alloy known as NIMONIC 80A 8pecification BS 2HR 201 of thickness .008 + .001 inches which is formed as a circular arc with it's two ends subsequently welded together. The ring is heat treated firstly for 1 hour at 925"C + 10 C in a vacuum, then force cooled, and finally heat treated for 4 hours at 750"C + 10 in vacuum.
As shown in Fig. 2 the ring in radial crosssection is of somewhat W-shape with two outwardly convex limbs 1 connected to a central loop 3 of which the sides 3a are parallel and relatively close together. The radius R of the central part of the loop is significantly less than the transition radius 8 between the sides 3a and the limbs 1, whiist the free ends 1 a of the limbs 1 which engage the surfaces or flanges to be sealed are straight, substantially parallel, and lightly lapped and polished.
Typically the outside diameter of the ring is 10.478 inches, the axial length is 0.248 inches, the inside radius S is .023 inches and the inside radius R is .009 inches. The length of the straight free ends 1 a is .020 inches, the inside diameter at the free ends is 10.2 inches, the inside diameter at the loop 3 is 10. 150 inches and the distance between the centres of radius S is .088 inches. The nominal radius T is .126 inches.
In the stages of ring formation illustrated in Figs. 3 to 3C inclusive, D is equivalent to the width of the space to be filled by a sealing ring which in this instance is made of metal such as steel, stainless steel, or an alloy with a high nickel content using appropriate heat treatments. The thickness T of the metal may in this instance be .3 mm (.012 inches). Fig.
3A shows the width D notionally divided into four equal parts D/4 defining centres of radius lines 0, K and L. Fig. 3A shows respective radii R3 and R4 where: R3 = D/2 - T and R4 = D/8 - T/2 Fig. 3B shows an added radius R1 where: R1 = R4 = D/8 - T/2 In Fig. 3C, J is a line drawn tangential to the centre of the central loop perpendicular to lines 0, K and L and 3D shows the addition of straight sections to the limbs as far as this line J.
Due to large variations in the size and shape of the recesses which are to be occupied by these ring, it is necessary on occasions to vary the relative dimensions of their constituent parts.
Stages in variation of the limb and loop radii are for example shown in Figs. 4 to 4C.
Firstly radius R4 is reduced in order to reduce the loop width Z. Then the radius R1 is reduced and the centre is positioned so that the part formed by radius R1 joins the reduced width loop and also still joins the part formed by radius R3. Finally, the straight part of the limb is reduced to the line J.
The mode of achieving variations in loop and straight limb part is shown in Figs. 5 to 5D.
Firstly the centre for radius R4 is moved from line B to line E (Fig. 5A), a distance which is equal to twice the metal thickness i.e. 2T. Also the straight part of each limb can be extended from line F (Fig. 5) to line G (Fig. 5B) that is to say by an amount of 2T.
The transition from Fig. 5 to Fig. 5C shows how the centre for radius R4 can be moved from line B to line F where the distance between lines B and F is 2T.
Finally the transition from Fig. 5 to Fig. 5D shows how the length of the flat part of the links can be reduced from line F to line H a decrease of T (the material thickness).
It is to be understood that any of the changes depicted between Figs. 3 to 5 inclusive can be made independently of the others or a combination of such changes can be made.
Fig. 6 shows a plural loop version of the sealing ring illustrated in Fig. 5 by the addition of an extra convolution to provide two loops of equal width with two radii R1, two radii R3, two radii R4 and one radius R5, the distance between the two loops being the same as the internal width of each loop. The loops have the same length as the outer limbs.
Fig. 7 shows a plural loop sealing ring similar to that which is shown in Fig. 7 except that, as a result of a change in the position of radius R4, the loops are elongated beyond the outer limbs.
Fig. 8 shows a variation of the sealing ring shdwn in Fig. 6 wherein by an increase in radius R5 there is an increased bridging dimension Z between the loops which in this embodiment also are the same length as the outer limbs.
Finally, Fig. 5 shows a two loop sealing ring wherein, as a result of the movement of the centres of radii, R1, R4 and R5 the loops or convolutions have non-parallel sides.

Claims (9)

1. A hollow metallic sealing ring comprised in radial cross-section of a pair of outwardly convex limbs which are contiguous with a loop formation having at least one straight sided loop, the limbs, from their junctions with the ends of the loop formation, being of increasing radius towards their free ends which are straight and substantially parallel.
2. A hollow metallic sealing ring as claimed in Claim 1, in which the radius of the curved end of the loop is less than the minimum radius of the said outwardly convex limbs.
3. A hollow metallic sealing ring as claimed in claim 1 or claim 2 in which the length of at least one loop is co-extensive with the length of the limbs.
4. A hollow metallic sealing ring as claimed in claim 1 or 2 in which the length of at least one loop is greater than the length of the limbs.
5. A hollow metallic sealing ring as claimed in any of claims 1 to 4 in which the distance between adjacent loops is substantially the same as the inside width of those loops.
6. A hollow metallic sealing ring as claimed in any of claims 1 to 4 in which the distance between adjacent loops exceeds the inside width of those loops.
7. A hollow metallic sealing ring as claimed in any of claims 1 to 6 in which one or more loops have parallel sides.
8. A hollow metallic sealing ring as claimed in any of claims 1 to 6 in which one or more loops have divergent sides.
9. A hollow metallic sealing ring which is shaped substantially as hereinbefore described with reference to, and as shown in, any of the figures of the accompanying drawings.
GB8710127A 1986-05-02 1987-04-29 Hollow metallic sealing ring Expired GB2190155B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8710127A GB2190155B (en) 1986-05-02 1987-04-29 Hollow metallic sealing ring

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB08610771A GB2189850A (en) 1986-05-02 1986-05-02 Metallic sealing rings
GB8710127A GB2190155B (en) 1986-05-02 1987-04-29 Hollow metallic sealing ring

Publications (3)

Publication Number Publication Date
GB8710127D0 GB8710127D0 (en) 1987-06-03
GB2190155A true GB2190155A (en) 1987-11-11
GB2190155B GB2190155B (en) 1989-12-06

Family

ID=26290710

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8710127A Expired GB2190155B (en) 1986-05-02 1987-04-29 Hollow metallic sealing ring

Country Status (1)

Country Link
GB (1) GB2190155B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0348569A1 (en) * 1988-06-29 1990-01-03 Specialist Sealing Limited Improvements relating to ring seals
US8162327B2 (en) * 2009-01-16 2012-04-24 Seal Science And Technology, Llc Metal seals for weld-deformed high temperature pneumatic ducting joints
CN102537350A (en) * 2012-02-14 2012-07-04 中国航空动力机械研究所 Sealing ring and aircraft engine with same

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1299173A (en) * 1968-10-23 1972-12-06 Corrugated Packing Sheet Metal Sealing means
GB1600966A (en) * 1977-10-04 1981-10-21 Pressure Science Inc Multiple convolution sealing ring
US4602795A (en) * 1985-12-06 1986-07-29 United Technologies Corporation Thermally expansive slip joint for formed sheet metal seals

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1299173A (en) * 1968-10-23 1972-12-06 Corrugated Packing Sheet Metal Sealing means
GB1600966A (en) * 1977-10-04 1981-10-21 Pressure Science Inc Multiple convolution sealing ring
US4602795A (en) * 1985-12-06 1986-07-29 United Technologies Corporation Thermally expansive slip joint for formed sheet metal seals

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0348569A1 (en) * 1988-06-29 1990-01-03 Specialist Sealing Limited Improvements relating to ring seals
US8162327B2 (en) * 2009-01-16 2012-04-24 Seal Science And Technology, Llc Metal seals for weld-deformed high temperature pneumatic ducting joints
CN102537350A (en) * 2012-02-14 2012-07-04 中国航空动力机械研究所 Sealing ring and aircraft engine with same
CN102537350B (en) * 2012-02-14 2015-05-06 中国航空动力机械研究所 Sealing ring and aircraft engine with same

Also Published As

Publication number Publication date
GB8710127D0 (en) 1987-06-03
GB2190155B (en) 1989-12-06

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Legal Events

Date Code Title Description
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
PE20 Patent expired after termination of 20 years

Effective date: 20070428