GB2191825A

GB2191825A - Brush seals

Info

Publication number: GB2191825A
Application number: GB08614785A
Authority: GB
Inventors: Douglas William Daniels
Original assignee: Rolls Royce PLC
Current assignee: Rolls Royce PLC
Priority date: 1986-06-18
Filing date: 1986-06-18
Publication date: 1987-12-23
Also published as: GB2191825B; FR2600381A1; FR2600381B1; GB8614785D0; JPS62298627A; DE3720069A1

Description

1 GB2191825A 1

SPECIFICATION

Means for retaining a body in a housing 0 1 This invention relates to a means for retaining a body in a housing, and is particularly relevant to preventing one or more brush seals rotating relative to each other or relative to the housing in which they are situated.

Brush seals, as described in our British Patent No 1450553 are well known for sealing between relatively rotating members. They comprise a plurality of bristle elements sandwiched between a pair of side-plates. The side-plates are generally annular in form and are conventionally housed in one of the members between which a seal is required.

The bristles are positioned to project a predetermined distance from the side plates, such that their ends act on the second member to effect the seal.

One major problem with brush seals is how to prevent them rotating relative to the member in which they are housed when in use.

One possible method is to provide the brush seal with a peg on one of its side plates and the housing with a corresponding hole, the seal is then positioned with the peg in the hole to prevent rotation thereof. This method, whilst working adequately necessitates both the seal and the housing being modified, a clearly expensive and undesirable requirement. Further to this, any seal which is inadvertently positioned with the wrong side- plate facing the hole will not be prevented from rotating relative to its housing.

A second method makes use of a ring which is loaded onto the side-face of the brush seal sufficiently to prevent the seal ro- tating in the housing and then securely fastened to the housing by screws or rivets. One problem with this method is that removal of the seal necessitates removal of the screws or rivets. Further to this, if the seal is replaced with one having a different thickness then new holes have to be provided in the ring or housing to ensure the same load factor. Both these tasks are time consuming and expensive.

It is an object of the present invention to provide a means for retaining a body in a housing which reduces and possibly eliminates the above mentioned disadvantages.

Accordingly, the present invention provides a retaining means for retaining a body, said means comprising a capsule having a first portion against which the body is positioned, a first deformable flange and a loading means, said loading means being positioned between the body and the first deformable flange, said first deformable flange being deformable onto said loading means such that the loading means is compressed and the body gripped between said loading means and the first end face by a force created by compression of the loading means.

A further object of the present invention is to provide a means for preventing the capsule rotating relative to a housing in which it is situated, said means comprising a second deformable flange provided on the capsule which is deformed into one or more recesses formed in the housing.

The present invention will now be more par- ticularly described by way of example only with reference to the accompanying drawings in which:

Figure 1 is a cross sectional view of the present invention and two brush seals.

figure 2 is a cross sectional view of the present invention installed in a housing.

Figure 3 and 4 are cross sectional views of alternative arrangement of the present invention.

Referring to Figure 1, a capsule (10) formed from sheet material rolled around the seals (12) or from a tube, is provided with a gener ally radially inwardly facing portion (14) and two deformable end portions (16 and 18).

The brush seals (12) are situated inside the capsule (10) such that they abutt the radially inwardly facing portion (14). A packing ring (17) is positioned adjacent the short sideplate (18) of the outermost brush seal (12) and acts as a loading surface against which a spring shown generally at (20) acts. The spring (20) comprises a ring of resilient material having a generally -U- shaped cross sectional form. The base of the spring (22) is slidably located on the inside of the capsule (10) whilst the sides (24, 26) extend generally radially inwards diverging at an angle to the radial plane W - The brush seals (12) are secured in position by deforming the end portion (16) of the capsule (10) inwardly such that it acts on one side of the spring (20) to deform it into its compressed shape as shown in Figure 2.

The retaining force which the spring (20) exerts on the brush seals (12) is dependent upon the angle at which the sides (24, 26) of the spring are set. One method of ensuring that the same retaining force is exerted by the spring (20) each time is to insert a segmented disk (not shown) inside a V section of the spring (20) during deformation of the end portion (16). This ensures that the spring (20) is not over compressed. The angle required for any given retaining force will depend on the shape and material properties of the spring (20).

Referring now particularly to Figure 2, the capsule (10) is installed in a housing (28) and retained therein by deforming the otherwise free end of the capsule (18) such that it comes into contact with the housing (28) and portions of it are deformed into recesses (30) formed therein to prevent rotation of the capsule (18) relative to said housing (28).

The inner diameter (d,) of the brush seal 2 GB2191825A 2 (12) is sized such that the bristle element ends (32) act on a member such as for example a shaft (34) to effect a seal therebetween.

Referring now to Figure 3, an alternative arrangement of the present invention might be to replace the 'Ll' shaped spring (20) with a substantially non-deformable packing ring (36) and to replace the packing ring (17) with a simple wave spring, shown at (38). The method of assembling the seals (12) in the capsule (10) and securing them therein remains substantially as already described and is therefore not described again.

Referring now to Figure 4, yet another arrangement of the present invention is shown. The 'Ll' shaped spring (20) shown in figures 1 and 2 has been replaced with a ring (40) having a generally 'L' shaped cross sectional form. A first portion of the ring (42) extends in a generally axial direction and the second portion (44) extends generally radially inwardly. The second portion (44) is angled relative to the radial plane (z) when not deflected (not shown) in a similar manner to that described for the spring (20). The magnitude of the angle depends on the material properties and the required spring force. The ring (40) is loaded onto the sidefaces of the seals (12) as previously described and retained therein by deforming the flange (16) of the capsule (10) over onto the first portion (42) of the ring (40).

It will be appreciated that the spring (20) may take any one of a number of forms as long as it is capable of providing the required retaining force on the seals (12).

Claims

1. A retaining means for retaining a body, said means comprising a capsule having a first portion against which the body is positioned, a first deformable flange and a loading means, said loading means being positioned between said body and said first deformable flange, said first deformable flange being deformable onto said loading means such that the loading means is compressed and the body gripped between said loading means and said first portion by a force created by the compression the loading means.

2. A retaining means according to claim 1 in which the capsule is situated in a housing and is provided with a second deformable flange which is deformable into one or more recesses formed in the housing.

3. A retaining means according to claim 1 or claim 2 in which the loading means comprises a ring of resilient material having a base and at least one generally radially inwardly extending side which diverges at an angle (e) to the radial plane (z).

4. A retaining means according to claim 1 or claim 2 in which the loading means corn- prised a wave spring.

5. A retaining means according to any one of claims 1 to 3 in which a packing ring is placed between the body and the loading means.

6. A retaining means according to any one of the preceding claims substantially as herebefore described with reference to Figures 1 to 3.

Printed for Her Majesty's Stationery Office by Burgess & Son (Abingdon) Ltd, Dd 8991685, 1987. Published at The Patent Office, 25 Southampton Buildings, London, WC2A 1 AY, from which copies may be obtained.

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